Primaquine to reduce transmission of Plasmodium falciparum malaria in Mali: a single-blind, dose-ranging, adaptive randomised phase 2 trial.

PubMed

Dicko, Alassane; Brown, Joelle M; Diawara, Halimatou; Baber, Ibrahima; Mahamar, Almahamoudou; Soumare, Harouna M; Sanogo, Koualy; Koita, Fanta; Keita, Sekouba; Traore, Sekou F; Chen, Ingrid; Poirot, Eugenie; Hwang, Jimee; McCulloch, Charles; Lanke, Kjerstin; Pett, Helmi; Niemi, Mikko; Nosten, François; Bousema, Teun; Gosling, Roly

2016-06-01

Single low doses of primaquine, when added to artemisinin-based combination therapy, might prevent transmission of Plasmodium falciparum malaria to mosquitoes. We aimed to establish the activity and safety of four low doses of primaquine combined with dihydroartemisinin-piperaquine in male patients in Mali. In this phase 2, single-blind, dose-ranging, adaptive randomised trial, we enrolled boys and men with uncomplicated P falciparum malaria at the Malaria Research and Training Centre (MRTC) field site in Ouelessebougou, Mali. All participants were confirmed positive carriers of gametocytes through microscopy and had normal function of glucose-6-phosphate dehydrogenase (G6PD) on colorimetric quantification. In the first phase, participants were randomly assigned (1:1:1) to one of three primaquine doses: 0 mg/kg (control), 0·125 mg/kg, and 0·5 mg/kg. Randomisation was done with a computer-generated randomisation list (in block sizes of six) and concealed with sealed, opaque envelopes. In the second phase, different participants were sequentially assigned (1:1) to 0·25 mg/kg primaquine or 0·0625 mg/kg primaquine. Primaquine tablets were dissolved into a solution and administered orally in a single dose. Participants were also given a 3 day course of dihydroartemisinin-piperaquine, administered by weight (320 mg dihydroartemisinin and 40 mg piperaquine per tablet). Outcome assessors were masked to treatment allocation, but participants were permitted to find out group assignment. Infectivity was assessed through membrane-feeding assays, which were optimised through the beginning part of phase one. The primary efficacy endpoint was the mean within-person percentage change in mosquito infectivity 2 days after primaquine treatment in participants who completed the study after optimisation of the infectivity assay, had both a pre-treatment infectivity measurement and at least one follow-up infectivity measurement, and who were given the correct primaquine dose. The safety endpoint was the mean within-person change in haemoglobin concentration during 28 days of study follow-up in participants with at least one follow-up visit. This study is registered with ClinicalTrials.gov, number NCT01743820. Between Jan 2, 2013, and Nov 27, 2014, we enrolled 81 participants. In the primary analysis sample (n=71), participants in the 0·25 mg/kg primaquine dose group (n=15) and 0·5 mg/kg primaquine dose group (n=14) had significantly lower mean within-person reductions in infectivity at day 2-92·6% (95% CI 78·3-100; p=0·0014) for the 0·25 mg/kg group; and 75·0% (45·7-100; p=0·014) for the 0·5 mg/kg primaquine group-compared with those in the control group (n=14; 11·3% [-27·4 to 50·0]). Reductions were not significantly different from control for participants assigned to the 0·0625 mg/kg dose group (n=16; 41·9% [1·4-82·5]; p=0·16) and the 0·125 mg/kg dose group (n=12; 54·9% [13·4-96·3]; p=0·096). No clinically meaningful or statistically significant drops in haemoglobin were recorded in any individual in the haemoglobin analysis (n=70) during follow-up. No serious adverse events were reported and adverse events did not differ between treatment groups. A single dose of 0·25 mg/kg primaquine, given alongside dihydroartemisinin-piperaquine, was safe and efficacious for the prevention of P falciparum malaria transmission in boys and men who are not deficient in G6PD. Future studies should assess the safety of single-dose primaquine in G6PD-deficient individuals to define the therapeutic range of primaquine to enable the safe roll-out of community interventions with primaquine. Bill & Melinda Gates Foundation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Single Low Dose Primaquine (0.25 mg/kg) Does Not Cause Clinically Significant Haemolysis in G6PD Deficient Subjects.

PubMed

Bancone, Germana; Chowwiwat, Nongnud; Somsakchaicharoen, Raweewan; Poodpanya, Lalita; Moo, Paw Khu; Gornsawun, Gornpan; Kajeechiwa, Ladda; Thwin, May Myo; Rakthinthong, Santisuk; Nosten, Suphak; Thinraow, Suradet; Nyo, Slight Naw; Ling, Clare L; Wiladphaingern, Jacher; Kiricharoen, Naw Lily; Moore, Kerryn A; White, Nicholas J; Nosten, Francois

2016-01-01

Primaquine is the only drug consistently effective against mature gametocytes of Plasmodium falciparum. The transmission blocking dose of primaquine previously recommended was 0.75 mg/kg (adult dose 45 mg) but its deployment was limited because of concerns over haemolytic effects in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD deficiency is an inherited X-linked enzymatic defect that affects an estimated 400 million people around the world with high frequencies (15-20%) in populations living in malarious areas. To reduce transmission in low transmission settings and facilitate elimination of P. falciparum, the World Health Organization now recommends adding a single dose of 0.25 mg/kg (adult dose 15 mg) to Artemisinin-based Combination Therapies (ACTs) without G6PD testing. Direct evidence of the safety of this low dose is lacking. Adverse events and haemoglobin variations after this treatment were assessed in both G6PD normal and deficient subjects in the context of targeted malaria elimination in a malaria endemic area on the North-Western Myanmar-Thailand border where prevalence of G6PD deficiency (Mahidol variant) approximates 15%. The tolerability and safety of primaquine (single dose 0.25 mg base/kg) combined with dihydroartemisinin-piperaquine (DHA-PPQ) given three times at monthly intervals was assessed in 819 subjects. Haemoglobin concentrations were estimated over the six months preceding the ACT + primaquine rounds of mass drug administration. G6PD deficiency was assessed with a phenotypic test and genotyping was performed in male subjects with deficient phenotypes and in all females. Fractional haemoglobin changes in relation to G6PD phenotype and genotype and primaquine round were assessed using linear mixed-effects models. No adverse events related to primaquine were reported during the trial. Mean fractional haemoglobin changes after each primaquine treatment in G6PD deficient subjects (-5.0%, -4.2% and -4.7%) were greater than in G6PD normal subjects (0.3%, -0.8 and -1.7%) but were clinically insignificant. Fractional drops in haemoglobin concentration larger than 25% following single dose primaquine were observed in 1.8% of the population but were asymptomatic. The single low dose (0.25mg/kg) of primaquine is clinically well tolerated and can be used safely without prior G6PD testing in populations with high prevalence of G6PD deficiency. The present evidence supports a broader use of low dose primaquine without G6PD testing for the treatment and elimination of falciparum malaria. ClinicalTrials.gov NCT01872702.

Use of primaquine and glucose-6-phosphate dehydrogenase deficiency testing: Divergent policies and practices in malaria endemic countries

PubMed Central

Recht, Judith; Ashley, Elizabeth A.

2018-01-01

Primaquine is the only available antimalarial drug that kills dormant liver stages of Plasmodium vivax and Plasmodium ovale malarias and therefore prevents their relapse (‘radical cure’). It is also the only generally available antimalarial that rapidly sterilises mature P. falciparum gametocytes. Radical cure requires extended courses of primaquine (usually 14 days; total dose 3.5–7 mg/kg), whereas transmissibility reduction in falciparum malaria requires a single dose (formerly 0.75 mg/kg, now a single low dose [SLD] of 0.25 mg/kg is recommended). The main adverse effect of primaquine is dose-dependent haemolysis in glucose 6-phosphate dehydrogenase (G6PD) deficiency, the most common human enzymopathy. X-linked mutations conferring varying degrees of G6PD deficiency are prevalent throughout malaria-endemic regions. Phenotypic screening tests usually detect <30% of normal G6PD activity, identifying nearly all male hemizygotes and female homozygotes and some heterozygotes. Unfortunately, G6PD deficiency screening is usually unavailable at point of care, and, as a consequence, radical cure is greatly underused. Both haemolytic risk (determined by the prevalence and severity of G6PD deficiency polymorphisms) and relapse rates vary, so there has been considerable uncertainty in both policies and practices related to G6PD deficiency testing and use of primaquine for radical cure. Review of available information on the prevalence and severity of G6PD variants together with countries’ policies for the use of primaquine and G6PD deficiency testing confirms a wide range of practices. There remains lack of consensus on the requirement for G6PD deficiency testing before prescribing primaquine radical cure regimens. Despite substantially lower haemolytic risks, implementation of SLD primaquine as a P. falciparum gametocytocide also varies. In Africa, a few countries have recently adopted SLD primaquine, yet many with areas of low seasonal transmission do not use primaquine as an antimalarial at all. Most countries that recommended the higher 0.75 mg/kg single primaquine dose for falciparum malaria (e.g., most countries in the Americas) have not changed their recommendation. Some vivax malaria–endemic countries where G6PD deficiency testing is generally unavailable have adopted the once-weekly radical cure regimen (0.75 mg/kg/week for 8 weeks), known to be safer in less severe G6PD deficiency variants. There is substantial room for improvement in radical cure policies and practices. PMID:29672516

Use of primaquine and glucose-6-phosphate dehydrogenase deficiency testing: Divergent policies and practices in malaria endemic countries.

PubMed

Recht, Judith; Ashley, Elizabeth A; White, Nicholas J

2018-04-01

Primaquine is the only available antimalarial drug that kills dormant liver stages of Plasmodium vivax and Plasmodium ovale malarias and therefore prevents their relapse ('radical cure'). It is also the only generally available antimalarial that rapidly sterilises mature P. falciparum gametocytes. Radical cure requires extended courses of primaquine (usually 14 days; total dose 3.5-7 mg/kg), whereas transmissibility reduction in falciparum malaria requires a single dose (formerly 0.75 mg/kg, now a single low dose [SLD] of 0.25 mg/kg is recommended). The main adverse effect of primaquine is dose-dependent haemolysis in glucose 6-phosphate dehydrogenase (G6PD) deficiency, the most common human enzymopathy. X-linked mutations conferring varying degrees of G6PD deficiency are prevalent throughout malaria-endemic regions. Phenotypic screening tests usually detect <30% of normal G6PD activity, identifying nearly all male hemizygotes and female homozygotes and some heterozygotes. Unfortunately, G6PD deficiency screening is usually unavailable at point of care, and, as a consequence, radical cure is greatly underused. Both haemolytic risk (determined by the prevalence and severity of G6PD deficiency polymorphisms) and relapse rates vary, so there has been considerable uncertainty in both policies and practices related to G6PD deficiency testing and use of primaquine for radical cure. Review of available information on the prevalence and severity of G6PD variants together with countries' policies for the use of primaquine and G6PD deficiency testing confirms a wide range of practices. There remains lack of consensus on the requirement for G6PD deficiency testing before prescribing primaquine radical cure regimens. Despite substantially lower haemolytic risks, implementation of SLD primaquine as a P. falciparum gametocytocide also varies. In Africa, a few countries have recently adopted SLD primaquine, yet many with areas of low seasonal transmission do not use primaquine as an antimalarial at all. Most countries that recommended the higher 0.75 mg/kg single primaquine dose for falciparum malaria (e.g., most countries in the Americas) have not changed their recommendation. Some vivax malaria-endemic countries where G6PD deficiency testing is generally unavailable have adopted the once-weekly radical cure regimen (0.75 mg/kg/week for 8 weeks), known to be safer in less severe G6PD deficiency variants. There is substantial room for improvement in radical cure policies and practices.

Comparison of the Cumulative Efficacy and Safety of Chloroquine, Artesunate, and Chloroquine-Primaquine in Plasmodium vivax Malaria.

PubMed

Chu, Cindy S; Phyo, Aung Pyae; Lwin, Khin Maung; Win, Htun Htun; San, Thida; Aung, Aye Aye; Raksapraidee, Rattanaporn; Carrara, Verena I; Bancone, Germana; Watson, James; Moore, Kerryn A; Wiladphaingern, Jacher; Proux, Stéphane; Sriprawat, Kanlaya; Winterberg, Markus; Cheah, Phaik Yeong; Chue, Amy L; Tarning, Joel; Imwong, Mallika; Nosten, François; White, Nicholas J

2018-06-08

Chloroquine has been recommended for Plasmodium vivax infections for >60 years, but resistance is increasing. To guide future therapies, the cumulative benefits of using slowly eliminated (chloroquine) vs rapidly eliminated (artesunate) antimalarials, and the risks and benefits of adding radical cure (primaquine) were assessed in a 3-way randomized comparison conducted on the Thailand-Myanmar border. Patients with uncomplicated P. vivax malaria were given artesunate (2 mg/kg/day for 5 days), chloroquine (25 mg base/kg over 3 days), or chloroquine-primaquine (0.5 mg/kg/day for 14 days) and were followed for 1 year. Recurrence rates and their effects on anemia were compared. Between May 2010 and October 2012, 644 patients were enrolled. Artesunate cleared parasitemia significantly faster than chloroquine. Day 28 recurrence rates were 50% with artesunate (112/224), 8% with chloroquine (18/222; P < .001), and 0.5% with chloroquine-primaquine (1/198; P < .001). Median times to first recurrence were 28 days (interquartile range [IQR], 21-42) with artesunate, 49 days (IQR, 35-74) with chloroquine, and 195 days (IQR, 82-281) with chloroquine-primaquine. Recurrence by day 28, was associated with a mean absolute reduction in hematocrit of 1% (95% confidence interval [CI], .3%-2.0%; P = .009). Primaquine radical cure reduced the total recurrences by 92.4%. One-year recurrence rates were 4.51 (95% CI, 4.19-4.85) per person-year with artesunate, 3.45 (95% CI, 3.18-3.75) with chloroquine (P = .002), and 0.26 (95% CI, .19-.36) with chloroquine-primaquine (P < .001). Vivax malaria relapses are predominantly delayed by chloroquine but prevented by primaquine. NCT01074905.

Single Low Dose Primaquine (0.25mg/kg) Does Not Cause Clinically Significant Haemolysis in G6PD Deficient Subjects

PubMed Central

Bancone, Germana; Chowwiwat, Nongnud; Somsakchaicharoen, Raweewan; Poodpanya, Lalita; Moo, Paw Khu; Gornsawun, Gornpan; Kajeechiwa, Ladda; Thwin, May Myo; Rakthinthong, Santisuk; Nosten, Suphak; Thinraow, Suradet; Nyo, Slight Naw; Ling, Clare L.; Wiladphaingern, Jacher; Kiricharoen, Naw Lily; Moore, Kerryn A.; White, Nicholas J.; Nosten, Francois

2016-01-01

Background Primaquine is the only drug consistently effective against mature gametocytes of Plasmodium falciparum. The transmission blocking dose of primaquine previously recommended was 0.75mg/kg (adult dose 45mg) but its deployment was limited because of concerns over haemolytic effects in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD deficiency is an inherited X-linked enzymatic defect that affects an estimated 400 million people around the world with high frequencies (15–20%) in populations living in malarious areas. To reduce transmission in low transmission settings and facilitate elimination of P. falciparum, the World Health Organization now recommends adding a single dose of 0.25mg/kg (adult dose 15mg) to Artemisinin-based Combination Therapies (ACTs) without G6PD testing. Direct evidence of the safety of this low dose is lacking. Adverse events and haemoglobin variations after this treatment were assessed in both G6PD normal and deficient subjects in the context of targeted malaria elimination in a malaria endemic area on the North-Western Myanmar-Thailand border where prevalence of G6PD deficiency (Mahidol variant) approximates 15%. Methods and Findings The tolerability and safety of primaquine (single dose 0.25 mg base/kg) combined with dihydroartemisinin-piperaquine (DHA-PPQ) given three times at monthly intervals was assessed in 819 subjects. Haemoglobin concentrations were estimated over the six months preceding the ACT + primaquine rounds of mass drug administration. G6PD deficiency was assessed with a phenotypic test and genotyping was performed in male subjects with deficient phenotypes and in all females. Fractional haemoglobin changes in relation to G6PD phenotype and genotype and primaquine round were assessed using linear mixed-effects models. No adverse events related to primaquine were reported during the trial. Mean fractional haemoglobin changes after each primaquine treatment in G6PD deficient subjects (-5.0%, -4.2% and -4.7%) were greater than in G6PD normal subjects (0.3%, -0.8 and -1.7%) but were clinically insignificant. Fractional drops in haemoglobin concentration larger than 25% following single dose primaquine were observed in 1.8% of the population but were asymptomatic. Conclusions The single low dose (0.25mg/kg) of primaquine is clinically well tolerated and can be used safely without prior G6PD testing in populations with high prevalence of G6PD deficiency. The present evidence supports a broader use of low dose primaquine without G6PD testing for the treatment and elimination of falciparum malaria. Trial Registration ClinicalTrials.gov NCT01872702 PMID:27010542

Novel Potent Metallocenes against Liver Stage Malaria

PubMed Central

Matos, Joana; da Cruz, Filipa P.; Cabrita, Élia; Gut, Jiri; Nogueira, Fátima; do Rosário, Virgílio E.; Moreira, Rui; Rosenthal, Philip J.; Prudêncio, Miguel

2012-01-01

Novel conjugates of the antimalarial drug primaquine (compound 1) with ferrocene, named primacenes, have been synthesized and screened for their activities against blood stage and liver stage malaria in vitro and host-vector transmission in vivo. Both transmission-blocking and blood-schizontocidal activities of the parent drug were conserved only in primacenes bearing a basic aliphatic amine group. Liver stage activity did not require this structural feature, and all metallocenes tested were comparable to or better than primaquine in this regard. Remarkably, the replacement of primaquine's aliphatic chain by hexylferrocene, as in compound 7, led to a ∼45-fold-higher level activity against liver stage parasitemia than that of primaquine. PMID:22155838

Primaquine: Modes of Action and Mechanisms of Drug Resistance.

DTIC Science & Technology

1975-06-30

on in vitro protein synthesis, nucleic acid synthesis in vitro and in isolated nuclei, in vitro lipid synthesis, andmembrane transport and permeability...vitro protein synthesis, nucleic acid synthesis in vitro and in isolated nuclei, in vitro lipid synthesis, and membrane transport and permeability. In...protein synthesis. 7 III. The effects of primaquine on nucleic acid synthesis in isolated nuclei. 7 IV. The effects of primaquine on DNA and RNA syntheses

Comparison of tafenoquine (WR238605) and primaquine in the post-exposure (terminal) prophylaxis of vivax malaria in Australian Defence Force personnel.

PubMed

Nasveld, Peter; Kitchener, Scott; Edstein, Michael; Rieckmann, Karl

2002-01-01

On return from duty in North Solomons Province (including Bougainville Island), Papua New Guinea, 586 Australian Defence Force personnel received either primaquine (14-d) or tafenoquine (3-d) post-exposure malaria prophylaxis. Within 12 months, 6 of the 214 volunteers receiving primaquine and 7 of 378 receiving tafenoquine had developed vivax malaria. Overall, volunteers preferred the shorter course of tafenoquine.

Enantiomeric separation of antimalarial drugs by capillary electrophoresis using neutral and negatively charged cyclodextrins.

PubMed

Németh, Krisztina; Tárkányi, Gábor; Varga, Erzsébet; Imre, Tímea; Mizsei, Réka; Iványi, Róbert; Visy, Júlia; Szemán, Julianna; Jicsinszky, László; Szente, Lajos; Simonyi, Miklós

2011-02-20

Capillary electrophoresis (CE) methods for chiral resolution of five antimalarial drugs (primaquine, tafenoquine, mefloquine, chloroquine and quinacrine) were developed by using a wide selection of neutral and anionic cyclodextrin (CD) derivatives. The use of sulfobutyl-β-CD and carboxymethyl-β-CD (CMBCD) resulted in good resolution of quinacrine and tafenoquine, respectively. New results are presented for resolutions of chloroquine and mefloquine. Application of carboxyalkyl- and sulfobutyl-CD derivatives provided improved resolution for primaquine. The impurity in primaquine sample detected by CE was identified as quinocide by MS and NMR. CMBCD provided not only the best separation of primaquine from quinocide but also the simultaneous complete resolution of both compounds. Copyright © 2010 Elsevier B.V. All rights reserved.

Randomized trial of 3-dose regimens of tafenoquine (WR238605) versus low-dose primaquine for preventing Plasmodium vivax malaria relapse.

PubMed

Walsh, Douglas S; Wilairatana, Polrat; Tang, Douglas B; Heppner, D Gray; Brewer, Thomas G; Krudsood, Srivicha; Silachamroon, Udomsak; Phumratanaprapin, Weerapong; Siriyanonda, Duangsuda; Looareesuwan, Sornchai

2004-10-15

Tafenoquine is an 8-aminoquinoline developed as a more effective replacement for primaquine. In a previous dose-ranging study in Thailand, 3 tafenoquine regimens with total doses ranging from 500 mg to 3000 mg prevented relapse of Plasmodium vivax malaria in most patients when administered 2 days after receipt of a blood schizonticidal dose of chloroquine. To improve convenience and to begin comparison of tafenoquine with primaquine, 80 patients with P. vivax infection were randomized to receive 1 of the following 5 treatments 1 day after receiving a blood schizonticidal dose of chloroquine: (A) tafenoquine, 300 mg per day for 7 days (n=18); (B) tafenoquine, 600 mg per day for 3 days (n=19); (C) tafenoquine, 600 mg as a single dose (n=18); (D) no further treatment (n=13); or (E) primaquine base, 15 mg per day for 14 days (n=12). The minimum duration of protocol follow-up was 8 weeks, with additional follow-up to 24 weeks. Forty-six of 55 tafenoquine recipients, 10 of 13 recipients of chloroquine only, and 12 of 12 recipients of chloroquine plus primaquine completed at least 8 weeks of follow-up (or had relapse). There was 1 relapse among recipients of chloroquine plus tafenoquine, 8 among recipients of chloroquine only, and 3 among recipients of chloroquine plus primaquine. The rate of protective efficacy (determined on the basis of reduction in incidence density) for all recipients of chloroquine plus tafenoquine, compared with recipients of chloroquine plus primaquine, was 92.6% (95% confidence interval, 7.3%-99.9%; P=.042, by Fisher's exact test). Tafenoquine doses as low as a single 600-mg dose may be useful for prevention of relapse of P. vivax malaria in Thailand.

Primaquine

MedlinePlus

... used alone or with another medication to treat malaria (a serious infection that is spread by mosquitoes ... coming back in people that are infected with malaria. Primaquine is in a class of medications called ...

The efficacy and tolerability of three different regimens of tafenoquine versus primaquine for post-exposure prophylaxis of Plasmodium vivax malaria in the Southwest Pacific.

PubMed

Elmes, N J; Nasveld, P E; Kitchener, S J; Kocisko, D A; Edstein, M D

2008-11-01

Tafenoquine is being developed for radical cure and post-exposure prophylaxis of Plasmodium vivax malaria. In an open-label study, 1512 Australian Defence Force personnel received one of three tafenoquine 3 d regimens [400 mg once daily (od), 200 mg twice daily (bid), 200 mg od] or daily primaquine (22.5 mg) plus doxycycline (100 mg) over 14 d in Bougainville and in Timor-Leste for post-exposure prophylaxis. The relapse rate of subjects treated in Bougainville with tafenoquine (n=173) was 1.2% (200 mg bid x 3 d) and 2.3% (400 mg od x 3 d), while primaquine plus doxycycline (n=175) was 3.4%. For subjects treated in Timor-Leste with tafenoquine (n=636), the relapse rate was 4.9% (200 mg od x 3 d), 5.3% (200 mg bid x 3 d) and 11.0% (400 mg od x 3d), while primaquine plus doxycycline (n=289) was 10.0%. The most frequent adverse events reported across all groups were nausea, abdominal distress and diarrhoea. There was a dose-dependent reduction in adverse events with a reduced dose of tafenoquine, with the lowest dose (total 600 mg over 3 d) producing rates of adverse events equivalent to that of primaquine plus doxycycline. The much shorter dosing regimen of tafenoquine should increase compliance, which is often suboptimal with primaquine after leaving an endemic area. [Australian New Zealand Clinical Trials Registry Number 12607000588493].

Malaria chemoprophylaxis in the age of drug resistance. II. Drugs that may be available in the future.

PubMed

Shanks, G D; Kain, K C; Keystone, J S

2001-08-01

All current regimens of malaria chemoprophylaxis have serious drawbacks as a result of either suboptimal efficacy, difficulty with medication compliance, or adverse events. Two 8-aminoquinolines may be approaching registration, with primaquine having completed its prophylactic field testing and tafenoquine having begun advanced field testing at the end of 2000. Primaquine has long been used for management of relapses of malaria, but in the past decade, it has been reexamined for use in malaria prevention in order to stop infection in the liver. In field trials performed in Indonesia and Colombia, the efficacy of primaquine for malaria prevention was approximately 90%, compared with that of placebo. Because of its short half-life, primaquine requires daily administration. For adults, the prevention regimen is 30 mg base daily (0.5 mg base/kg/day), and it can probably be discontinued soon after departure from an area where malaria is endemic. To kill parasites that already exist in the liver, terminal prophylaxis is given after exposure to relapses of malaria infection; for adults, such prophylaxis usually consists of 15 mg base (0.3 mg base/kg/day) given daily for 2 weeks. Primaquine-induced gastrointestinal disturbances can be minimized if the drug is taken with food. Neither primaquine nor tafenoquine should be given to persons with glucose-6-phosphate dehydrogenase deficiency, to avoid the development of potentially severe drug-induced hemolysis. Tafenoquine is an analogue of primaquine that is more potent than the parent drug. Field trials in Kenya, Ghana, Gabon, and Southeast Asia have demonstrated an efficacy rate of approximately 90% for tafenoquine. Its long half-life allows for infrequent dosing (currently tested at 200 mg base/week), and its effect on parasites at the liver stage may allow for drug discontinuation at the time of departure from the area of endemicity.

Causal prophylactic efficacy of primaquine, tafenoquine, and atovaquone-proguanil against Plasmodium cynomolgi in a rhesus monkey model.

PubMed

DiTusa, Charles; Kozar, Michael P; Pybus, Brandon; Sousa, Jason; Berman, Jonathan; Gettayacamin, Montip; Im-erbsin, Rawiwan; Tungtaeng, Anchalee; Ohrt, Colin

2014-10-01

Since the 1940s, the large animal model to assess novel causal prophylactic antimalarial agents has been the Plasmodium cynomolgi sporozoite-infected Indian-origin rhesus monkey. In 2009 the model was reassessed with 3 clinical standards: primaquine (PQ), tafenoquine (TQ), and atovaquone-proguanil. Both control monkeys were parasitemic on day 8 post-sporozoite inoculation on day 0. Primaquine at 1.78 mg base/kg/day on days (-1) to 8 protected 1 monkey and delayed parasitemia patency of the other monkey to day 49. Tafenoquine at 6 mg base/kg/day on days (-1) to 1 protected both monkeys. However, atovaquone-proguanil at 10 mg atovaquone/kg/day on days (-1) to 8 did not protect either monkey and delayed patency only to days 18-19. Primaquine and TQ at the employed regimens are proposed as appropriate doses of positive control drugs for the model at present.

Simultaneous quantitation of chloroquine and primaquine by UPLC-DAD and comparison with a HPLC-DAD method.

PubMed

Miranda, Tiago A; Silva, Pedro H R; Pianetti, Gerson A; César, Isabela C

2015-01-28

Chloroquine and primaquine are the first-line treatment recommended by World Health Organization for malaria caused by Plasmodium vivax. Since the problem of counterfeit or substandard anti-malarials is well established all over the world, the development of rapid and reliable methods for quality control analysis of these drugs is essential. Thus, the aim of this study was to develop and validate a novel UPLC-DAD method for simultaneously quantifying chloroquine and primaquine in tablet formulations. The UPLC separation was carried out using a Hypersil C18 column (50 × 2.1 mm id; 1.9 μm particle size) and a mobile phase composed of acetonitrile (A) and 0.1% aqueous triethylamine, pH 3.0 adjusted with phosphoric acid (B), at a flow rate 0.6 mL/min. Gradient elution was employed. UV detection was performed at 260 nm. UPLC method was fully validated and the results were compared to a conventional HPLC-DAD method for the analysis of chloroquine and primaquine in tablet formulations. UPLC method was shown to be linear (r2 > 0.99), precise (CV < 2.0%), accurate (recovery rates from 98.11 to 99.83%), specific, and robust. No significant differences were observed between the chloroquine and primaquine contents obtained by UPLC and HPLC methods. However, UPLC method promoted faster analyses, better chromatographic performance and lower solvent consumption. The developed UPLC method was shown to be a rapid and suitable technique to quantify chloroquine and primaquine in pharmaceutical preparations and may be successfully employed for quality control analysis.

Tolerability and safety of weekly primaquine against relapse of Plasmodium vivax in Cambodians with glucose-6-phosphate dehydrogenase deficiency.

PubMed

Kheng, Sim; Muth, Sinoun; Taylor, Walter R J; Tops, Narann; Kosal, Khem; Sothea, Khon; Souy, Phum; Kim, Saorin; Char, Chuor Meng; Vanna, Chan; Ly, Po; Ringwald, Pascal; Khieu, Virak; Kerleguer, Alexandra; Tor, Pety; Baird, John K; Bjorge, Steven; Menard, Didier; Christophel, Eva

2015-08-25

Primaquine is used to prevent Plasmodium vivax relapse; however, it is not implemented in many malaria-endemic countries, including Cambodia, for fear of precipitating primaquine-induced acute haemolytic anaemia in patients with glucose-6-phosphate dehydrogenase deficiency (G6PDd). Reluctance to use primaquine is reinforced by a lack of quality safety data. This study was conducted to assess the tolerability of a primaquine regimen in Cambodian severely deficient G6PD variants to ascertain whether a weekly primaquine could be given without testing for G6PDd. From January 2013 to January 2014, Cambodians with acute vivax malaria were treated with dihydroartemisinin/piperaquine on days (D) 0, 1 and 2 with weekly doses of primaquine 0.75 mg/kg for 8 weeks (starting on D0, last dose on D49), and followed until D56. Participants' G6PD status was confirmed by G6PD genotype and measured G6PD activity. The primary outcome was treatment completion without primaquine toxicity defined as any one of: (1) severe anaemia (haemoglobin [Hb] <7 g/dL), (2) a >25 % fractional fall in Hb from D0, (3) the need for a blood transfusion, (4) haemoglobinuria, (5) acute kidney injury (an increase in baseline serum creatinine >50 %) or (6) methaemoglobinaemia >20 %. We enrolled 75 patients with a median age of 24 years (range 5-63); 63 patients (84 %) were male. Eighteen patients were G6PDd (17/18 had the Viangchan variant) and had D0 G6PD activity ranging from 0.1 to 1.5 U/g Hb (median 0.85 U/g Hb). In the 57 patients with normal G6PD (G6PDn), D0 G6PD activity ranged from 6.9 to 18.5 U/g Hb (median 12 U/g Hb). Median D0 Hb concentrations were similar (P = 0.46) between G6PDd (13 g/dL, range 9.6-16) and G6PDn (13.5 g/dL, range 9-16.3) and reached a nadir on D2 in both groups: 10.8 g/dL (8.2-15.3) versus 12.4 g/dL (8.8-15.2) (P = 0.006), respectively. By D7, five G6PDd patients (27.7 %) had a >25 % fall in Hb, compared to 0 G6PDn patients (P = 0.00049). One of these G6PDd patients required a blood transfusion (D0-D5 Hb, 10.0-7.2 g/dL). No patients developed severe anaemia, haemoglobinuria, a methaemoglobin concentration >4.9 %, or acute kidney injury. Vivax-infected G6PDd Cambodian patients demonstrated significant, mostly transient, falls in Hb and one received a blood transfusion. Weekly primaquine in G6PDd patients mandates medical supervision and pre-treatment screening for G6PD status. The feasibility of implementing a package of G6PDd testing and supervised primaquine should be explored. The trial was registered on 3/1/2013 and the registration number is ACTRN12613000003774.

Enantioselective pharmacokinetics of primaquine in healthy human volunteers

USDA-ARS?s Scientific Manuscript database

Primaquine (PQ), a racemic drug, is the only treatment available for radical cure of relapsing Plasmodium vivax malaria and blocking transmission of P. falciparum malaria. Recent studies have shown differential pharmacologic and toxicologic profiles of individual PQ enantiomers in rodent, dog, and p...

Origins and implications of neglect of G6PD deficiency and primaquine toxicity in Plasmodium vivax malaria

PubMed Central

Baird, Kevin

2015-01-01

Most of the tens of millions of clinical attacks caused by Plasmodium vivax each year likely originate from dormant liver forms called hypnozoites. We do not systematically attack that reservoir because the only drug available, primaquine, is poorly suited to doing so. Primaquine was licenced for anti-relapse therapy in 1952 and became available despite threatening patients having an inborn deficiency of glucose-6-phosphate dehydrogenase (G6PD) with acute haemolytic anaemia. The standard method for screening G6PD deficiency, the fluorescent spot test, has proved impractical where most malaria patients live. The blind administration of daily primaquine is dangerous, but so too are the relapses invited by withholding treatment. Absent G6PD screening, providers must choose between risking harm by the parasite or its treatment. How did this dilemma escape redress in science, clinical medicine and public health? This review offers critical historic reflection on the neglect of this serious problem in the chemotherapy of P. vivax. PMID:25943156

Compliance with Antimalarial Chemoprophylaxis Recommendations for Wounded United States Military Personnel Admitted to a Military Treatment Facility

PubMed Central

Rini, Elizabeth A.; Weintrob, Amy C.; Tribble, David R.; Lloyd, Bradley A.; Warkentien, Tyler E.; Shaikh, Faraz; Li, Ping; Aggarwal, Deepak; Carson, M. Leigh; Murray, Clinton K.

2014-01-01

Malaria chemoprophylaxis is used as a preventive measure in military personnel deployed to malaria-endemic countries. However, limited information is available on compliance with chemoprophylaxis among trauma patients during hospitalization and after discharge. Therefore, we assessed antimalarial primary chemoprophylaxis and presumptive antirelapse therapy (primaquine) compliance among wounded United States military personnel after medical evacuation from Afghanistan (June 2009–August 2011) to Landstuhl Regional Medical Center in Landstuhl, Germany, and then to three U.S. military hospitals. Among admissions at Landstuhl Regional Medical Center, 74% of 2,540 patients were prescribed primary chemoprophylaxis and < 1% were prescribed primaquine. After transfer of 1,331 patients to U.S. hospitals, 93% received primary chemoprophylaxis and 33% received primaquine. Of 751 trauma patients with available post-admission data, 42% received primary chemoprophylaxis for four weeks, 33% received primaquine for 14 days, and 17% received both. These antimalarial chemoprophylaxis prescription rates suggest that improved protocols to continue malaria chemoprophylaxis in accordance with force protection guidelines are needed. PMID:24732457

Therapeutic principles of primaquine against relapse of Plasmodium vivax malaria

NASA Astrophysics Data System (ADS)

Baird, J. K.

2018-03-01

Plasmodium vivax causes tens of millions of clinical attacks annually all across the malarious globe. Unlike the other major cause of human malaria, Plasmodium falciparum, P. vivax places dormant stages called hypnozoites into the human liver that later awaken and provoke multiple clinical attacks in the weeks, months, and few years following the infectious anopheline mosquito bite. The only available treatment to prevent those recurrent attacks is primaquine (hypnozoitocide), and it must be administered with the drugs applied to end the acute attack (blood schizontocides). This paper reviews the therapeutic principles of applying primaquine to achieve radical cure of acute vivax malaria.

Effects of novel triple-stage antimalarial ionic liquids on lipid membrane models.

PubMed

Ferraz, Ricardo; Pinheiro, Marina; Gomes, Ana; Teixeira, Cátia; Prudêncio, Cristina; Reis, Salette; Gomes, Paula

2017-09-01

Primaquine-based ionic liquids, obtained by acid-base reaction between parent primaquine and cinnamic acids, were recently found as triple-stage antimalarial hits. These ionic compounds displayed significant activity against both liver- and blood-stage Plasmodium parasites, as well as against stage V P. falciparum parasites. Remarkably, blood-stage activity of the ionic liquids against both chloroquine-sensitive (3D7) and resistant (Dd2) P. falciparum strains was clearly superior to those of the respective covalent (amide) analogues and of parent primaquine. Having hypothesized that such behaviour might be ascribed to an enhanced ability of the ionic compounds to permeate into Plasmodium-infected erythrocytes, we have carried out a differential scanning calorimetry-based study of the interactions between the ionic liquids and membrane models. Results provide evidence, at the molecular level, that the primaquine-derived ionic liquids may contribute to an increased permeation of the parent drug into malaria-infected erythrocytes, which has relevant implications towards novel antimalarial approaches based on ionic liquids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Compliance with antimalarial chemoprophylaxis recommendations for wounded United States military personnel admitted to a military treatment facility.

PubMed

Rini, Elizabeth A; Weintrob, Amy C; Tribble, David R; Lloyd, Bradley A; Warkentien, Tyler E; Shaikh, Faraz; Li, Ping; Aggarwal, Deepak; Carson, M Leigh; Murray, Clinton K

2014-06-01

Malaria chemoprophylaxis is used as a preventive measure in military personnel deployed to malaria-endemic countries. However, limited information is available on compliance with chemoprophylaxis among trauma patients during hospitalization and after discharge. Therefore, we assessed antimalarial primary chemoprophylaxis and presumptive antirelapse therapy (primaquine) compliance among wounded United States military personnel after medical evacuation from Afghanistan (June 2009-August 2011) to Landstuhl Regional Medical Center in Landstuhl, Germany, and then to three U.S. military hospitals. Among admissions at Landstuhl Regional Medical Center, 74% of 2,540 patients were prescribed primary chemoprophylaxis and < 1% were prescribed primaquine. After transfer of 1,331 patients to U.S. hospitals, 93% received primary chemoprophylaxis and 33% received primaquine. Of 751 trauma patients with available post-admission data, 42% received primary chemoprophylaxis for four weeks, 33% received primaquine for 14 days, and 17% received both. These antimalarial chemoprophylaxis prescription rates suggest that improved protocols to continue malaria chemoprophylaxis in accordance with force protection guidelines are needed. © The American Society of Tropical Medicine and Hygiene.

Study protocol for a randomised controlled double-blinded trial of the dose-dependent efficacy and safety of primaquine for clearance of gametocytes in children with uncomplicated falciparum malaria in Uganda.

PubMed

Eziefula, Alice Chijioke; Staedke, Sarah G; Yeung, Shunmay; Webb, Emily; Kamya, Moses; White, Nicholas J; Bousema, Teun; Drakeley, Chris

2013-03-26

For the purpose of blocking transmission of Plasmodium falciparum malaria from humans to mosquitoes, a single dose of primaquine is recommended by the WHO as an addition to artemisinin combination therapy. Primaquine clears gametocytes but causes dose-dependent haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Evidence is needed to inform the optimal dosing of primaquine for malaria elimination programmes and for the purpose of interrupting the spread of artemisinin-resistant malaria. This study investigates the efficacy and safety of reducing doses of primaquine for clearance of gametocytes in participants with normal G6PD status. In this prospective, four-armed randomised placebo-controlled double-blinded trial, children aged 1-10 years, weighing over 10 kg, with haemoglobin ≥8 g/dl and uncomplicated P falciparum malaria are treated with artemether lumefantrine and randomised to receive a dose of primaquine (0.1, 0.4 or 0.75 mg base/kg) or placebo on the third day of treatment. Participants are followed up for 28 days. Gametocytaemia is measured by quantitative nucleic acid sequence-based analysis on days 0, 2, 3, 7, 10 and 14 with a primary endpoint of the number of days to gametocyte clearance in each treatment arm and secondarily the area under the curve of gametocyte density over time. Analysis is for non-inferiority of efficacy compared to the reference dose, 0.75 mg base/kg. Safety is assessed by pair-wise comparisons of the arithmetic mean (±SD) change in haemoglobin concentration per treatment arm and analysed for superiority to placebo and incidence of adverse events. Ethics and dissemination Approval was obtained from the ethical committees of Makerere University School of Medicine, the Ugandan National Council of Science and Technology and the London School of Hygiene and Tropical Medicine. These will be disseminated to inform malaria elimination policy, through peer-reviewed publication and academic presentations.

Chemotherapy of Rodent Malaria. Part 1

DTIC Science & Technology

1987-10-01

to produce exaggerated resistance factors (I 90 values). For example, the ED of chloroquine against the artemisinin 90 resistant ART strain...primaquine, quinine, cinchonine, quinidine, mefloquine, halofantrine, artemisinin , pyronaridine, mepacrine and Mannich bases (such as WR 228258). It is...RC. It is markedly resistant to primaquine and possesses slight cross-resistance to quinidine, mefloquine, artemisinin . There is also a marked cross

New pentasubstituted pyrrole hybrid atorvastatin-quinoline derivatives with antiplasmodial activity.

PubMed

Carvalho, Rita C C; Martins, Wagner A; Silva, Tayara P; Kaiser, Carlos R; Bastos, Mônica M; Pinheiro, Luiz C S; Krettli, Antoniana U; Boechat, Núbia

2016-04-15

Cerebral malaria is caused by Plasmodium falciparum. Atorvastatin (AVA) is a pentasubstituted pyrrole, which has been tested as an adjuvant in the treatment of cerebral malaria. Herein, a new class of hybrids of AVA and aminoquinolines (primaquine and chloroquine derivatives) has been synthesized. The quinolinic moiety was connected to the pentasubstituted pyrrole from AVA by a linker group (CH2)n=2-4 units. The activity of the compounds increased with the size of the carbons chain. Compound with n=4 and 7-chloroquinolinyl has displayed better activity (IC50=0.40 μM) than chloroquine. The primaquine derivative showed IC50=1.41 μM, being less toxic and more active than primaquine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tafenoquine for the treatment of recurrent Plasmodium vivax malaria.

PubMed

Kitchener, Scott; Nasveld, Peter; Edstein, Michael D

2007-03-01

Tafenoquine was used to treat Plasmodium vivax malaria cases who had previously failed treatment with chloroquine and primaquine. Chloroquine was followed by a loading dose of tafenoquine (200 mg base/day for 3 days) and 200 mg a week was given for 8 weeks. One of 27 treated patients relapsed after 6 months of observation. A standard course of chloroquine administered with 8 weeks of tafenoquine may be more effective than chloroquine with primaquine (22.5 mg/day for 14 days) in preventing additional P. vivax relapses. Larger studies are required to optimize the combination, but our findings suggest that an extended use of tafenoquine may be required to prevent relapses of primaquine-tolerant strains of P. vivax malaria.

Rationale for recommending a lower dose of primaquine as a Plasmodium falciparum gametocytocide in populations where G6PD deficiency is common

PubMed Central

2012-01-01

In areas of low malaria transmission, it is currently recommended that a single dose of primaquine (0.75 mg base/kg; 45 mg adult dose) be added to artemisinin combination treatment (ACT) in acute falciparum malaria to block malaria transmission. Review of studies of transmission-blocking activity based on the infectivity of patients or volunteers to anopheline mosquitoes, and of haemolytic toxicity in glucose 6-dehydrogenase (G6PD) deficient subjects, suggests that a lower primaquine dose (0.25 mg base/kg) would be safer and equally effective. This lower dose could be deployed together with ACTs without G6PD testing wherever use of a specific gametocytocide is indicated. PMID:23237606

Rationale for recommending a lower dose of primaquine as a Plasmodium falciparum gametocytocide in populations where G6PD deficiency is common.

PubMed

White, Nicholas J; Qiao, Li Guo; Qi, Gao; Luzzatto, Lucio

2012-12-14

In areas of low malaria transmission, it is currently recommended that a single dose of primaquine (0.75 mg base/kg; 45 mg adult dose) be added to artemisinin combination treatment (ACT) in acute falciparum malaria to block malaria transmission. Review of studies of transmission-blocking activity based on the infectivity of patients or volunteers to anopheline mosquitoes, and of haemolytic toxicity in glucose 6-dehydrogenase (G6PD) deficient subjects, suggests that a lower primaquine dose (0.25 mg base/kg) would be safer and equally effective. This lower dose could be deployed together with ACTs without G6PD testing wherever use of a specific gametocytocide is indicated.

Drug Evaluation in the Plasmodium Falciparum-Aotus Model

DTIC Science & Technology

1996-03-01

infections. Although erythromycin is inactive against chloroquine -resistant falciparum infections, an analogue , azithromycin, is effective in vitro...s, infection parameters characterized, confirm their response to chloroquine , and then expand the evaluation of WR 238605, a primaquine analogue ... chloroquine resistance was confirmed, as was the activity of WR 238605 (a primaquine analogue ), 1.0 mglkg (x 3 days) cleared parasitemias but with

Combined chloroquine, sulfadoxine/pyrimethamine and primaquine against Plasmodium falciparum in Central Java, Indonesia

PubMed Central

Lederman, Edith R; Maguire, Jason D; Sumawinata, Iwa W; Chand, Krisin; Elyazar, Iqbal; Estiana, Lusi; Sismadi, Priyanto; Bangs, Michael J; Baird, J Kevin

2006-01-01

Background Chloroquine (CQ) or sulfadoxine-pyrimethamine (SP) monotherapy for Plasmodium falciparum often leads to therapeutic failure in Indonesia. Combining CQ with other drugs, like SP, may provide an affordable, available and effective option where artemisinin-combined therapies (ACT) are not licensed or are unavailable. Methods This study compared CQ (n = 29 subjects) versus CQ + SP (with or without primaquine; n = 88) for clinical and parasitological cure of uncomplicated falciparum malaria in the Menoreh Hills region of southern Central Java, Indonesia. Gametocyte clearance rates were measured with (n = 56 subjects) and without (n = 61) a single 45 mg dose of primaquine (PQ). Results After 28 days, 58% of subjects receiving CQ had cleared parasitaemia and remained aparasitaemic, compared to 94% receiving CQ combined with SP (p < 0.001). Msp-2 genotyping permitted reinfection-adjusted cure rates for CQ and CQ combined with SP, 70% and 99%, respectively (p = 0.0006). Conclusion Primaquine exerted no apparent affect on cure of asexual stage parasitaemia, but clearly accelerated clearance of gametocytes. CQ combined with SP was safe and well-tolerated with superior efficacy over CQ for P. falciparum parasitaemia in this study. PMID:17105658

8-Aminoquinolines from Walter Reed Army Institute for Research for treatment and prophylaxis of Pneumocystis pneumonia in rat models.

PubMed Central

Bartlett, M S; Queener, S F; Tidwell, R R; Milhous, W K; Berman, J D; Ellis, W Y; Smith, J W

1991-01-01

Three 8-aminoquinolines from the Walter Reed Army Institute for Research (WRAIR), WR6026, WR238605, and WR242511, strongly inhibited Pneumocystis carinii growth in vitro at 1 microgram/ml. This activity was similar to that of primaquine. In rat therapy models, the WRAIR compounds affected Pneumocystis pneumonia at doses as low as 0.25 mg/kg (WR242511) or 0.5 mg/kg (WR6026 and WR238605). At these doses, primaquine alone was ineffective as therapy. In a rat prophylaxis model, all three WRAIR 8-aminoquinolines were extremely effective at daily doses of 0.57 mg/kg, showing activity greater than that of primaquine at this dosage and comparable to that of trimethoprim-sulfamethoxazole at 50/250 mg/kg. PMID:2024961

G6PD Deficiency Prevalence and Estimates of Affected Populations in Malaria Endemic Countries: A Geostatistical Model-Based Map

PubMed Central

Howes, Rosalind E.; Piel, Frédéric B.; Patil, Anand P.; Nyangiri, Oscar A.; Gething, Peter W.; Dewi, Mewahyu; Hogg, Mariana M.; Battle, Katherine E.; Padilla, Carmencita D.; Baird, J. Kevin; Hay, Simon I.

2012-01-01

Background Primaquine is a key drug for malaria elimination. In addition to being the only drug active against the dormant relapsing forms of Plasmodium vivax, primaquine is the sole effective treatment of infectious P. falciparum gametocytes, and may interrupt transmission and help contain the spread of artemisinin resistance. However, primaquine can trigger haemolysis in patients with a deficiency in glucose-6-phosphate dehydrogenase (G6PDd). Poor information is available about the distribution of individuals at risk of primaquine-induced haemolysis. We present a continuous evidence-based prevalence map of G6PDd and estimates of affected populations, together with a national index of relative haemolytic risk. Methods and Findings Representative community surveys of phenotypic G6PDd prevalence were identified for 1,734 spatially unique sites. These surveys formed the evidence-base for a Bayesian geostatistical model adapted to the gene's X-linked inheritance, which predicted a G6PDd allele frequency map across malaria endemic countries (MECs) and generated population-weighted estimates of affected populations. Highest median prevalence (peaking at 32.5%) was predicted across sub-Saharan Africa and the Arabian Peninsula. Although G6PDd prevalence was generally lower across central and southeast Asia, rarely exceeding 20%, the majority of G6PDd individuals (67.5% median estimate) were from Asian countries. We estimated a G6PDd allele frequency of 8.0% (interquartile range: 7.4–8.8) across MECs, and 5.3% (4.4–6.7) within malaria-eliminating countries. The reliability of the map is contingent on the underlying data informing the model; population heterogeneity can only be represented by the available surveys, and important weaknesses exist in the map across data-sparse regions. Uncertainty metrics are used to quantify some aspects of these limitations in the map. Finally, we assembled a database of G6PDd variant occurrences to inform a national-level index of relative G6PDd haemolytic risk. Asian countries, where variants were most severe, had the highest relative risks from G6PDd. Conclusions G6PDd is widespread and spatially heterogeneous across most MECs where primaquine would be valuable for malaria control and elimination. The maps and population estimates presented here reflect potential risk of primaquine-associated harm. In the absence of non-toxic alternatives to primaquine, these results represent additional evidence to help inform safe use of this valuable, yet dangerous, component of the malaria-elimination toolkit. Please see later in the article for the Editors' Summary PMID:23152723

G6PD deficiency prevalence and estimates of affected populations in malaria endemic countries: a geostatistical model-based map.

PubMed

Howes, Rosalind E; Piel, Frédéric B; Patil, Anand P; Nyangiri, Oscar A; Gething, Peter W; Dewi, Mewahyu; Hogg, Mariana M; Battle, Katherine E; Padilla, Carmencita D; Baird, J Kevin; Hay, Simon I

2012-01-01

Primaquine is a key drug for malaria elimination. In addition to being the only drug active against the dormant relapsing forms of Plasmodium vivax, primaquine is the sole effective treatment of infectious P. falciparum gametocytes, and may interrupt transmission and help contain the spread of artemisinin resistance. However, primaquine can trigger haemolysis in patients with a deficiency in glucose-6-phosphate dehydrogenase (G6PDd). Poor information is available about the distribution of individuals at risk of primaquine-induced haemolysis. We present a continuous evidence-based prevalence map of G6PDd and estimates of affected populations, together with a national index of relative haemolytic risk. Representative community surveys of phenotypic G6PDd prevalence were identified for 1,734 spatially unique sites. These surveys formed the evidence-base for a Bayesian geostatistical model adapted to the gene's X-linked inheritance, which predicted a G6PDd allele frequency map across malaria endemic countries (MECs) and generated population-weighted estimates of affected populations. Highest median prevalence (peaking at 32.5%) was predicted across sub-Saharan Africa and the Arabian Peninsula. Although G6PDd prevalence was generally lower across central and southeast Asia, rarely exceeding 20%, the majority of G6PDd individuals (67.5% median estimate) were from Asian countries. We estimated a G6PDd allele frequency of 8.0% (interquartile range: 7.4-8.8) across MECs, and 5.3% (4.4-6.7) within malaria-eliminating countries. The reliability of the map is contingent on the underlying data informing the model; population heterogeneity can only be represented by the available surveys, and important weaknesses exist in the map across data-sparse regions. Uncertainty metrics are used to quantify some aspects of these limitations in the map. Finally, we assembled a database of G6PDd variant occurrences to inform a national-level index of relative G6PDd haemolytic risk. Asian countries, where variants were most severe, had the highest relative risks from G6PDd. G6PDd is widespread and spatially heterogeneous across most MECs where primaquine would be valuable for malaria control and elimination. The maps and population estimates presented here reflect potential risk of primaquine-associated harm. In the absence of non-toxic alternatives to primaquine, these results represent additional evidence to help inform safe use of this valuable, yet dangerous, component of the malaria-elimination toolkit. Please see later in the article for the Editors' Summary.

A randomized, double-blind, active-control trial to evaluate the efficacy and safety of a three day course of tafenoquine monotherapy for the treatment of Plasmodium vivax malaria.

PubMed

Fukuda, Mark M; Krudsood, Srivicha; Mohamed, Khadeeja; Green, Justin A; Warrasak, Sukhuma; Noedl, Harald; Euswas, Ataya; Ittiverakul, Mali; Buathong, Nillawan; Sriwichai, Sabaithip; Miller, R Scott; Ohrt, Colin

2017-01-01

Tafenoquine is an investigational 8-aminoquinoline for the prevention of Plasmodium vivax relapse. Tafenoquine has a long half-life and the potential for more convenient dosing, compared with the currently recommended 14-day primaquine regimen. This randomized, active-control, double-blind trial was conducted in Bangkok, Thailand. Seventy patients with microscopically confirmed P. vivax were randomized (2:1) to tafenoquine 400 mg once daily for 3 days or 2500 mg total dose chloroquine phosphate (1500 mg chloroquine base) given over 3 days plus primaquine 15 mg daily for 14 days. Patients were followed to day 120. Day 28 adequate clinical response rate in the per-protocol population was 93% (40/43) (90%CI 83-98%) with tafenoquine, and 100% (22/22) (90%CI 87-100%) with chloroquine/primaquine. Day 120 relapse prevention was 100% (35/35) with tafenoquine (90%CI 92-100%), and 95% (19/20) (90%CI 78-100%) with chloroquine/primaquine. Mean (SD) parasite, gametocyte and fever clearance times with tafenoquine were 82.5 h (32.3), 49.1 h (33.0), and 41.1 h (31.4) versus 40.0 h (15.7), 22.7 h (16.4), and 24.7 h (17.7) with chloroquine/primaquine, respectively. Peak methemoglobin was 1.4-25.6% (median 7.4%, mean 9.1%) in the tafenoquine arm, and 0.5-5.9% (median 1.5%, mean 1.9%) in the chloroquine/primaquine arm. There were no clinical symptoms of methemoglobinemia in any patient. Although there was no difference in efficacy in this study, the slow rate of parasite, gametocyte and fever clearance indicates that tafenoquine should not be used as monotherapy for radical cure of P. vivax malaria. Also, monotherapy increases the potential risk of resistance developing to this long-acting agent. Clinical trials of single-dose tafenoquine 300 mg combined with standard 3-day chloroquine or artemisinin-based combination therapy are ongoing. Clinicaltrials.gov NCT01290601.

A randomized, double-blind, active-control trial to evaluate the efficacy and safety of a three day course of tafenoquine monotherapy for the treatment of Plasmodium vivax malaria

PubMed Central

Krudsood, Srivicha; Mohamed, Khadeeja; Green, Justin A.; Warrasak, Sukhuma; Noedl, Harald; Euswas, Ataya; Ittiverakul, Mali; Buathong, Nillawan; Sriwichai, Sabaithip; Miller, R. Scott; Ohrt, Colin

2017-01-01

Background Tafenoquine is an investigational 8-aminoquinoline for the prevention of Plasmodium vivax relapse. Tafenoquine has a long half-life and the potential for more convenient dosing, compared with the currently recommended 14-day primaquine regimen. Methods This randomized, active-control, double-blind trial was conducted in Bangkok, Thailand. Seventy patients with microscopically confirmed P. vivax were randomized (2:1) to tafenoquine 400 mg once daily for 3 days or 2500 mg total dose chloroquine phosphate (1500 mg chloroquine base) given over 3 days plus primaquine 15 mg daily for 14 days. Patients were followed to day 120. Results Day 28 adequate clinical response rate in the per-protocol population was 93% (40/43) (90%CI 83–98%) with tafenoquine, and 100% (22/22) (90%CI 87–100%) with chloroquine/primaquine. Day 120 relapse prevention was 100% (35/35) with tafenoquine (90%CI 92–100%), and 95% (19/20) (90%CI 78–100%) with chloroquine/primaquine. Mean (SD) parasite, gametocyte and fever clearance times with tafenoquine were 82.5 h (32.3), 49.1 h (33.0), and 41.1 h (31.4) versus 40.0 h (15.7), 22.7 h (16.4), and 24.7 h (17.7) with chloroquine/primaquine, respectively. Peak methemoglobin was 1.4–25.6% (median 7.4%, mean 9.1%) in the tafenoquine arm, and 0.5–5.9% (median 1.5%, mean 1.9%) in the chloroquine/primaquine arm. There were no clinical symptoms of methemoglobinemia in any patient. Discussion Although there was no difference in efficacy in this study, the slow rate of parasite, gametocyte and fever clearance indicates that tafenoquine should not be used as monotherapy for radical cure of P. vivax malaria. Also, monotherapy increases the potential risk of resistance developing to this long-acting agent. Clinical trials of single-dose tafenoquine 300 mg combined with standard 3-day chloroquine or artemisinin-based combination therapy are ongoing. Trial registration Clinicaltrials.gov NCT01290601 PMID:29121061

G6PD deficiency at Sumba in Eastern Indonesia is prevalent, diverse and severe: implications for primaquine therapy against relapsing Vivax malaria.

PubMed

Satyagraha, Ari Winasti; Sadhewa, Arkasha; Baramuli, Vanessa; Elvira, Rosalie; Ridenour, Chase; Elyazar, Iqbal; Noviyanti, Rintis; Coutrier, Farah Novita; Harahap, Alida Roswita; Baird, J Kevin

2015-03-01

Safe treatment of Plasmodium vivax requires diagnosis of both the infection and status of erythrocytic glucose-6-phosphate dehydrogenase (G6PD) activity because hypnozoitocidal therapy against relapse requires primaquine, which causes a mild to severe acute hemolytic anemia in G6PD deficient patients. Many national malaria control programs recommend primaquine therapy without G6PD screening but with monitoring due to a broad lack of G6PD deficiency screening capacity. The degree of risk in doing so hinges upon the level of residual G6PD activity among the variants present in any given area. We conducted studies on Sumba Island in eastern Indonesia in order to assess the potential threat posed by primaquine therapy without G6PD screening. We sampled 2,033 residents of three separate districts in western Sumba for quantitative G6PD activity and 104 (5.1%) were phenotypically deficient (<4.6U/gHb; median normal 10U/gHb). The villages were in two distinct ecosystems, coastal and inland. A positive correlation occurred between the prevalence of malaria and G6PD deficiency: 5.9% coastal versus inland 0.2% for malaria (P<0.001), and 6.7% and 3.1% for G6PD deficiency (P<0.001) at coastal and inland sites, respectively. The dominant genotypes of G6PD deficiency were Vanua Lava, Viangchan, and Chatham, accounting for 98.5% of the 70 samples genotyped. Subjects expressing the dominant genotypes all had less than 10% of normal enzyme activities and were thus considered severe variants. Blind administration of anti-relapse primaquine therapy at Sumba would likely impose risk of serious harm.

G6PD Deficiency at Sumba in Eastern Indonesia Is Prevalent, Diverse and Severe: Implications for Primaquine Therapy against Relapsing Vivax Malaria

PubMed Central

Satyagraha, Ari Winasti; Sadhewa, Arkasha; Baramuli, Vanessa; Elvira, Rosalie; Ridenour, Chase; Elyazar, Iqbal; Noviyanti, Rintis; Coutrier, Farah Novita; Harahap, Alida Roswita; Baird, J. Kevin

2015-01-01

Safe treatment of Plasmodium vivax requires diagnosis of both the infection and status of erythrocytic glucose-6-phosphate dehydrogenase (G6PD) activity because hypnozoitocidal therapy against relapse requires primaquine, which causes a mild to severe acute hemolytic anemia in G6PD deficient patients. Many national malaria control programs recommend primaquine therapy without G6PD screening but with monitoring due to a broad lack of G6PD deficiency screening capacity. The degree of risk in doing so hinges upon the level of residual G6PD activity among the variants present in any given area. We conducted studies on Sumba Island in eastern Indonesia in order to assess the potential threat posed by primaquine therapy without G6PD screening. We sampled 2,033 residents of three separate districts in western Sumba for quantitative G6PD activity and 104 (5.1%) were phenotypically deficient (<4.6U/gHb; median normal 10U/gHb). The villages were in two distinct ecosystems, coastal and inland. A positive correlation occurred between the prevalence of malaria and G6PD deficiency: 5.9% coastal versus inland 0.2% for malaria (P<0.001), and 6.7% and 3.1% for G6PD deficiency (P<0.001) at coastal and inland sites, respectively. The dominant genotypes of G6PD deficiency were Vanua Lava, Viangchan, and Chatham, accounting for 98.5% of the 70 samples genotyped. Subjects expressing the dominant genotypes all had less than 10% of normal enzyme activities and were thus considered severe variants. Blind administration of anti-relapse primaquine therapy at Sumba would likely impose risk of serious harm. PMID:25746733

Implications of current therapeutic restrictions for primaquine and tafenoquine in the radical cure of vivax malaria.

PubMed

Watson, James; Taylor, Walter R J; Bancone, Germana; Chu, Cindy S; Jittamala, Podjanee; White, Nicholas J

2018-04-01

The 8-aminoquinoline antimalarials, the only drugs which prevent relapse of vivax and ovale malaria (radical cure), cause dose-dependent oxidant haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Patients with <30% and <70% of normal G6PD activity are not given standard regimens of primaquine and tafenoquine, respectively. Both drugs are currently considered contraindicated in pregnant and lactating women. Quantitative G6PD enzyme activity data from 5198 individuals were used to estimate the proportions of heterozygous females who would be ineligible for treatment at the 30% and 70% activity thresholds, and the relationship with the severity of the deficiency. This was used to construct a simple model relating allele frequency in males to the potential population coverage of tafenoquine and primaquine under current prescribing restrictions. Independent of G6PD deficiency, the current pregnancy and lactation restrictions will exclude ~13% of females from radical cure treatment. This could be reduced to ~4% if 8-aminoquinolines can be prescribed to women breast-feeding infants older than 1 month. At a 30% activity threshold, approximately 8-19% of G6PD heterozygous women are ineligible for primaquine treatment; at a 70% threshold, 50-70% of heterozygous women and approximately 5% of G6PD wild type individuals are ineligible for tafenoquine treatment. Thus, overall in areas where the G6PDd allele frequency is >10% more than 15% of men and more than 25% of women would be unable to receive tafenoquine. In vivax malaria infected patients these proportions will be lowered by any protective effect against P. vivax conferred by G6PD deficiency. If tafenoquine is deployed for radical cure, primaquine will still be needed to obtain high population coverage. Better radical cure antimalarial regimens are needed.

Optimization of primaquine diphosphate tablet formulation for controlled drug release using the mixture experimental design.

PubMed

Duque, Marcelo Dutra; Kreidel, Rogério Nepomuceno; Taqueda, Maria Elena Santos; Baby, André Rolim; Kaneko, Telma Mary; Velasco, Maria Valéria Robles; Consiglieri, Vladi Olga

2013-01-01

A tablet formulation based on hydrophilic matrix with a controlled drug release was developed, and the effect of polymer concentrations on the release of primaquine diphosphate was evaluated. To achieve this purpose, a 20-run, four-factor with multiple constraints on the proportions of the components was employed to obtain tablet compositions. Drug release was determined by an in vitro dissolution study in phosphate buffer solution at pH 6.8. The polynomial fitted functions described the behavior of the mixture on simplex coordinate systems to study the effects of each factor (polymer) on tablet characteristics. Based on the response surface methodology, a tablet composition was optimized with the purpose of obtaining a primaquine diphosphate release closer to a zero order kinetic. This formulation released 85.22% of the drug for 8 h and its kinetic was studied regarding to Korsmeyer-Peppas model, (Adj-R(2) = 0.99295) which has confirmed that both diffusion and erosion were related to the mechanism of the drug release. The data from the optimized formulation were very close to the predictions from statistical analysis, demonstrating that mixture experimental design could be used to optimize primaquine diphosphate dissolution from hidroxypropylmethyl cellulose and polyethylene glycol matrix tablets.

Glucose-6-phosphate dehydrogenase status and risk of hemolysis in Plasmodium falciparum-infected African children receiving single-dose primaquine.

PubMed

Eziefula, Alice C; Pett, Helmi; Grignard, Lynn; Opus, Salome; Kiggundu, Moses; Kamya, Moses R; Yeung, Shunmay; Staedke, Sarah G; Bousema, Teun; Drakeley, Chris

2014-08-01

Glucose-6-phosphate dehydrogenase (G6PD) enzyme function and genotype were determined in Ugandan children with uncomplicated falciparum malaria enrolled in a primaquine trial after exclusion of severe G6PD deficiency by fluorescent spot test. G6PD A- heterozygotes and hemizygotes/homozygotes experienced dose-dependent lower hemoglobin concentrations after treatment. No severe anemia was observed. Copyright © 2014, Eziefula et al.

Haemolysis in G6PD Heterozygous Females Treated with Primaquine for Plasmodium vivax Malaria: A Nested Cohort in a Trial of Radical Curative Regimens.

PubMed

Chu, Cindy S; Bancone, Germana; Moore, Kerryn A; Win, Htun Htun; Thitipanawan, Niramon; Po, Christina; Chowwiwat, Nongnud; Raksapraidee, Rattanaporn; Wilairisak, Pornpimon; Phyo, Aung Pyae; Keereecharoen, Lily; Proux, Stéphane; Charunwatthana, Prakaykaew; Nosten, François; White, Nicholas J

2017-02-01

Radical cure of Plasmodium vivax malaria with 8-aminoquinolines (primaquine or tafenoquine) is complicated by haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD heterozygous females, because of individual variation in the pattern of X-chromosome inactivation (Lyonisation) in erythroid cells, may have low G6PD activity in the majority of their erythrocytes, yet are usually reported as G6PD "normal" by current phenotypic screening tests. Their haemolytic risk when treated with 8-aminoquinolines has not been well characterized. In a cohort study nested within a randomised clinical trial that compared different treatment regimens for P. vivax malaria, patients with a normal standard NADPH fluorescent spot test result (≳30%-40% of normal G6PD activity) were randomised to receive 3 d of chloroquine or dihydroartemisinin-piperaquine in combination with primaquine, either the standard high dose of 0.5 mg base/kg/day for 14 d or a higher dose of 1 mg base/kg/d for 7 d. Patterns of haemolysis were compared between G6PD wild-type and G6PD heterozygous female participants. Between 21 February 2012 and 04 July 2014, 241 female participants were enrolled, of whom 34 were heterozygous for the G6PD Mahidol variant. Haemolysis was substantially greater and a larger proportion of participants reached the threshold of clinically significant haemolysis (fractional haematocrit reduction >25%) in G6PD heterozygotes taking the higher (7 d) primaquine dose (9/17 [53%]) compared with G6PD heterozygotes taking the standard high (14 d) dose (2/16 [13%]; p = 0.022). In heterozygotes, the mean fractional haematocrit reductions were correspondingly greater with the higher primaquine dose (7-d regimen): -20.4% (95% CI -26.0% to -14.8%) (nadir on day 5) compared with the standard high (14 d) dose: -13.1% (95% CI -17.6% to -8.6%) (nadir day 6). Two heterozygotes taking the higher (7 d) primaquine dose required blood transfusion. In wild-type participants, mean haematocrit reductions were clinically insignificant and similar with both doses: -5.8 (95% CI -7.2% to -4.4%) (nadir day 3) compared with -5.5% (95% CI -7.4% to -3.7%) (nadir day 4), respectively. Limitations to this nested cohort study are that the primary objective of the trial was designed to measure efficacy and not haemolysis in relation to G6PD genotype and that the heterozygote groups were small. Higher daily doses of primaquine have the potential to cause clinically significant haemolysis in G6PD heterozygous females who are reported as phenotypically normal with current point of care tests. ClinicalTrials.gov NCT01640574.

CYP2D6 activity and the risk of recurrence of Plasmodium vivax malaria in the Brazilian Amazon: a prospective cohort study.

PubMed

Brasil, Larissa W; Rodrigues-Soares, Fernanda; Santoro, Ana B; Almeida, Anne C G; Kühn, Andrea; Ramasawmy, Rajendranath; Lacerda, Marcus V G; Monteiro, Wuelton M; Suarez-Kurtz, Guilherme

2018-02-01

CYP2D6 pathway mediates the activation of primaquine into active metabolite(s) in hepatocytes. CYP2D6 is highly polymorphic, encoding CYP2D6 isoforms with normal, reduced, null or increased activity. It is hypothesized that Plasmodium vivax malaria patients with defective CYP2D6 function would be at increased risk for primaquine failure to prevent recurrence. The aim of this study was to investigate the association of CYP2D6 polymorphisms and inferred CYP2D6 phenotypes with malaria recurrence in patients from the Western Brazilian Amazon, following chloroquine/primaquine combined therapy. The prospective cohort consisted of P. vivax malaria patients who were followed for 6 months after completion of the chloroquine/primaquine therapy. Recurrence was defined as one or more malaria episodes, 28-180 days after the initial episode. Genotyping for nine CYP2D6 SNPs and copy number variation was performed using TaqMan assays in a Fast 7500 Real-Time System. CYP2D6 star alleles (haplotypes), diplotypes and CYP2D6 phenotypes were inferred, and the activity score system was used to define the functionality of the CYP2D6 diplotypes. CYP2D6 activity scores (AS) were dichotomized at ≤ 1 (gPM, gIM and gNM-S phenotypes) and ≥ 1.5 (gNM-F and gUM phenotypes). Genotyping was successfully performed in 190 patients (44 with recurrence and 146 without recurrences). Recurrence incidence was higher in individuals presenting reduced activity CYP2D6 phenotypes (adjusted relative risk = 1.89, 95% CI 1.01-3.70; p = 0.049). Attributable risk and population attributable fraction were 11.5 and 9.9%, respectively. The time elapsed from the first P. vivax malaria episode until the recurrence did not differ between patients with AS of ≤ 1 versus ≥ 1.5 (p = 0.917). The results suggest that CYP2D6 polymorphisms are associated with increased risk of recurrence of vivax malaria, following chloroquine-primaquine combined therapy. This association is interpreted as the result of reduced conversion of primaquine into its active metabolites in patients with reduced CYP2D6 enzymatic activity.

Effect of Drugs on the Lethality in Mice of the Venoms and Neurotoxins from Sundry Snakes

DTIC Science & Technology

1990-07-10

nicergoline , primaquine, verapamil, and vesamicol protected mice from the lethality6_)f B. caeruleus venom, B. multicinctus venom, r " and/or’l...the venom or toxin was recorded 24 hr later. Diltia.-em. nicergoline . primaquine, verapamil. and vesamicol protected mice from the lethality of B...hydrochloride were purchased from Sigma Chemical Co., St. Louis, MO, U.S.A. Nicergoline (10-methoxy-1,6-dimethylergoline-8-r-methanol 5

Malaria prophylaxis/radical cure: recent experiences of the Australian Defence Force.

PubMed

Edstein, M D; Walsh, D S; Eamsila, C; Sasiprapha, T; Nasveld, P E; Kitchener, S; Rieckmann, K H

2001-01-01

Since the eighties, the Australian Defence Force has deployed soldiers in malaria-endemic areas: Cambodia, Somalia, Rwanda, Bougainville, and East Timor. Currently, doxycycline is used as first line prophylactic drug and mefloquine is recommended for those who cannot tolerate the antibiotic. In 1998, the Australian Defence Force participated in the evaluation of tafenoquine for prophylaxis of both falciparum and vivax malaria in Thai soldiers. At the completion of this six-month study, 29 of 205 soldiers had come down with malaria including eight with falciparum malaria, 20 with vivax malaria, and one with mixed infection. A total of 28 of the 101 soldiers in the placebo group were infected with malaria as compared with only one of the 104 soldiers in the tafenoquine group. In 1999, another study was started on the island of Bougainville to compare the effectiveness a 3-day course of tafenoquine and a 14-day course of primaquine for radical cure of vivax malaria. At the present time, 411 soldiers have completed the study including 201 in tafenoquine arm and 210 in primaquine arm. Seven soldiers in each arm developed vivax malaria after returning to Australia. These results indicate that tafenoquine is not superior to primaquine in preventing vivax malaria. However study participants preferred the shorter course using tafenoquine and operationally it was found to be more suitable than primaquine.

G6PD deficiency: a classic example of pharmacogenetics with on-going clinical implications

PubMed Central

Luzzatto, Lucio; Seneca, Elisa

2014-01-01

That primaquine and other drugs can trigger acute haemolytic anaemia in subjects who have an inherited mutation of the glucose 6-phosphate dehydrogenase (G6PD) gene has been known for over half a century: however, these events still occur, because when giving the drug either the G6PD status of a person is not known, or the risk of this potentially life-threatening complication is under-estimated. Here we review briefly the genetic basis of G6PD deficiency, and then the pathophysiology and the clinical features of drug-induced haemolysis; we also update the list of potentially haemolytic drugs (which includes rasburicase). It is now clear that it is not good practice to give one of these drugs before testing a person for his/her G6PD status, especially in populations in whom G6PD deficiency is common. We discuss therefore how G6PD testing can be done reconciling safety with cost; this is once again becoming of public health importance, as more countries are moving along the pathway of malaria elimination, that might require mass administration of primaquine. Finally, we sketch the triangular relationship between malaria, antimalarials such as primaquine, and G6PD deficiency: which is to some extent protective against malaria, but also a genetically determined hazard when taking primaquine. PMID:24372186

Efficacy and safety of primaquine and methylene blue for prevention of Plasmodium falciparum transmission in Mali: a phase 2, single-blind, randomised controlled trial.

PubMed

Dicko, Alassane; Roh, Michelle E; Diawara, Halimatou; Mahamar, Almahamoudou; Soumare, Harouna M; Lanke, Kjerstin; Bradley, John; Sanogo, Koualy; Kone, Daouda T; Diarra, Kalifa; Keita, Sekouba; Issiaka, Djibrilla; Traore, Sekou F; McCulloch, Charles; Stone, Will J R; Hwang, Jimee; Müller, Olaf; Brown, Joelle M; Srinivasan, Vinay; Drakeley, Chris; Gosling, Roly; Chen, Ingrid; Bousema, Teun

2018-06-01

Primaquine and methylene blue are gametocytocidal compounds that could prevent Plasmodium falciparum transmission to mosquitoes. We aimed to assess the efficacy and safety of primaquine and methylene blue in preventing human to mosquito transmission of P falciparum among glucose-6-phosphate dehydrogenase (G6PD)-normal, gametocytaemic male participants. This was a phase 2, single-blind, randomised controlled trial done at the Clinical Research Centre of the Malaria Research and Training Centre (MRTC) of the University of Bamako (Bamako, Mali). We enrolled male participants aged 5-50 years with asymptomatic P falciparum malaria. G6PD-normal participants with gametocytes detected by blood smear were randomised 1:1:1:1 in block sizes of eight, using a sealed-envelope design, to receive either sulfadoxine-pyrimethamine and amodiaquine, sulfadoxine-pyrimethamine and amodiaquine plus a single dose of 0·25 mg/kg primaquine, dihydroartemisinin-piperaquine, or dihydroartemisinin-piperaquine plus 15 mg/kg per day methylene blue for 3 days. Laboratory staff, investigators, and insectary technicians were masked to the treatment group and gametocyte density of study participants. The study pharmacist and treating physician were not masked. Participants could request unmasking. The primary efficacy endpoint, analysed in all infected patients with at least one infectivity measure before and after treatment, was median within-person percentage change in mosquito infectivity 2 and 7 days after treatment, assessed by membrane feeding. This study is registered with ClinicalTrials.gov, number NCT02831023. Between June 27, 2016, and Nov 1, 2016, 80 participants were enrolled and assigned to the sulfadoxine-pyrimethamine and amodiaquine (n=20), sulfadoxine-pyrimethamine and amodiaquine plus primaquine (n=20), dihydroartemisinin-piperaquine (n=20), or dihydroartemisinin-piperaquine plus methylene blue (n=20) groups. Among participants infectious at baseline (54 [68%] of 80), those in the sulfadoxine-pyrimethamine and amodiaquine plus primaquine group (n=19) had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with sulfadoxine-pyrimethamine and amodiaquine alone (n=12; -10·2%, IQR -143·9 to 56·6; p<0·0001). The dihydroartemisinin-piperaquine plus methylene blue (n=11) group had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with dihydroartemisinin-piperaquine alone (n=12; -6·0%, IQR -126·1 to 86·9; p<0·0001). Haemoglobin changes were similar between gametocytocidal arms and their respective controls. After exclusion of blue urine, adverse events were similar across all groups (59 [74%] of 80 participants had 162 adverse events overall, 145 [90%] of which were mild). Adding a single dose of 0·25 mg/kg primaquine to sulfadoxine-pyrimethamine and amodiaquine or 3 days of 15 mg/kg per day methylene blue to dihydroartemisinin-piperaquine was highly efficacious for preventing P falciparum transmission. Both primaquine and methylene blue were well tolerated. Bill & Melinda Gates Foundation, European Research Council. Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.

Implications of current therapeutic restrictions for primaquine and tafenoquine in the radical cure of vivax malaria

PubMed Central

Taylor, Walter R. J.; Bancone, Germana; Chu, Cindy S.; Jittamala, Podjanee; White, Nicholas J.

2018-01-01

Background The 8-aminoquinoline antimalarials, the only drugs which prevent relapse of vivax and ovale malaria (radical cure), cause dose-dependent oxidant haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Patients with <30% and <70% of normal G6PD activity are not given standard regimens of primaquine and tafenoquine, respectively. Both drugs are currently considered contraindicated in pregnant and lactating women. Methods Quantitative G6PD enzyme activity data from 5198 individuals were used to estimate the proportions of heterozygous females who would be ineligible for treatment at the 30% and 70% activity thresholds, and the relationship with the severity of the deficiency. This was used to construct a simple model relating allele frequency in males to the potential population coverage of tafenoquine and primaquine under current prescribing restrictions. Findings Independent of G6PD deficiency, the current pregnancy and lactation restrictions will exclude ~13% of females from radical cure treatment. This could be reduced to ~4% if 8-aminoquinolines can be prescribed to women breast-feeding infants older than 1 month. At a 30% activity threshold, approximately 8–19% of G6PD heterozygous women are ineligible for primaquine treatment; at a 70% threshold, 50–70% of heterozygous women and approximately 5% of G6PD wild type individuals are ineligible for tafenoquine treatment. Thus, overall in areas where the G6PDd allele frequency is >10% more than 15% of men and more than 25% of women would be unable to receive tafenoquine. In vivax malaria infected patients these proportions will be lowered by any protective effect against P. vivax conferred by G6PD deficiency. Conclusion If tafenoquine is deployed for radical cure, primaquine will still be needed to obtain high population coverage. Better radical cure antimalarial regimens are needed. PMID:29677199

N-cinnamoylated aminoquinolines as promising antileishmanial agents.

PubMed

Vale-Costa, S; Costa-Gouveia, J; Pérez, B; Silva, T; Teixeira, C; Gomes, P; Gomes, M S

2013-10-01

A series of cinnamic acid conjugates of primaquine and chloroquine were evaluated for their in vitro antileishmanial activities. Although primaquine derivatives had modest activity, chloroquine conjugates exhibited potent activity against both promastigotes (50% inhibitory concentration [IC50] = 2.6 to 21.8 μM) and intramacrophagic amastigotes (IC50 = 1.2 to 9.3 μM) of Leishmania infantum. Both the high activity of these chloroquine analogues and their mild-to-low toxicity toward host cells make them promising leads for the discovery of new antileishmanial agents.

Glucose-6-phosphate dehydrogenase deficiency in two returning Operation Iraqi Freedom soldiers who developed hemolytic anemia while receiving primaquine prophylaxis for malaria.

PubMed

Carr, Marcus E; Fandre, Matthew N; Oduwa, Felix O

2005-04-01

Use of antimalarial prophylaxis continues to be routine practice among military personnel returning from areas where malaria is endemic. Primaquine may be used for terminal prophylaxis against Plasmodium ovale and Plasmodium vivax. Serious complications of this regimen are infrequent. We report the occurrence of significant hemolytic anemia for two soldiers returning from Operation Iraqi Freedom. They presented with dark urine, headaches, and classic laboratory findings of hemolysis. Both soldiers were subsequently found to have glucose-6-phosphate dehydrogenase deficiency, and both responded to conservative treatment and cessation of medication. Although this complication is unusual, medical personnel involved in the care of recently returned deployed service members should be alert to its potential occurrence among patients who are receiving antimalarial prophylaxis. This complication could be completely avoided with prescreening of personnel for glucose-6-phosphate dehydrogenase deficiency, as is currently done in the Air Force and Navy, before the use of primaquine.

N-Cinnamoylated Aminoquinolines as Promising Antileishmanial Agents

PubMed Central

Vale-Costa, S.; Costa-Gouveia, J.; Pérez, B.; Silva, T.; Teixeira, C.; Gomes, P.

2013-01-01

A series of cinnamic acid conjugates of primaquine and chloroquine were evaluated for their in vitro antileishmanial activities. Although primaquine derivatives had modest activity, chloroquine conjugates exhibited potent activity against both promastigotes (50% inhibitory concentration [IC50] = 2.6 to 21.8 μM) and intramacrophagic amastigotes (IC50 = 1.2 to 9.3 μM) of Leishmania infantum. Both the high activity of these chloroquine analogues and their mild-to-low toxicity toward host cells make them promising leads for the discovery of new antileishmanial agents. PMID:23917315

Antimalarial Activities in New Pyrrolo(3,2-f)Quinazoline-1,3-Diamine Derivatives

DTIC Science & Technology

2005-12-01

aminoquinoline drugs (2, 3), water, a highly undesirable physical property for large-scale syn- namely, primaquine and tafenoquine . Central nervous...compounds were determined by a modified Thompson test (1). This test either primaquine or tafenoquine . measures the survivability of mice and parasite...0.625 5/5 3 0.3125 4/5 3 / 0.15625 4/5 3a 0.5 0/2 Tafenoquine 10 5/5 1 2/2 2/2 3 2/2 2.5 4/5 Cured monkeys stayed parasite free for 100 days PT. 1.25

Treatment of acute vivax malaria with tafenoquine.

PubMed

Nasveld, Peter; Kitchener, Scott

2005-01-01

Tafenoquine is an 8-aminoquiniline related to primaquine with pre-clinical activity against a range of malaria species. We treated two acute cases of vivax malaria with tafenoquine (800 mg over three days) alone, instead of conventional chloroquine (1500 mg over three days) and primaquine (420 mg over 14 days). In addition to the convenience of this regimen, the rapid parasite clearances observed, coupled with a good clinical response and lack of recrudescence or relapse, indicate that further investigation of tafenoquine in the treatment of vivax malaria is warranted.

G6PD Deficiency and Antimalarial Efficacy for Uncomplicated Malaria in Bangladesh: A Prospective Observational Study.

PubMed

Ley, Benedikt; Alam, Mohammad Shafiul; Thriemer, Kamala; Hossain, Mohammad Sharif; Kibria, Mohammad Golam; Auburn, Sarah; Poirot, Eugenie; Price, Ric N; Khan, Wasif Ali

2016-01-01

The Bangladeshi national treatment guidelines for uncomplicated malaria follow WHO recommendations but without G6PD testing prior to primaquine administration. A prospective observational study was conducted to assess the efficacy of the current antimalarial policy. Patients with uncomplicated malaria, confirmed by microscopy, attending a health care facility in the Chittagong Hill Tracts, Bangladesh, were treated with artemether-lumefantrine (days 0-2) plus single dose primaquine (0.75mg/kg on day2) for P. falciparum infections, or with chloroquine (days 0-2) plus 14 days primaquine (3.5mg/kg total over 14 days) for P. vivax infections. Hb was measured on days 0, 2 and 9 in all patients and also on days 16 and 30 in patients with P. vivax infection. Participants were followed for 30 days. The study was registered with the clinical trials website (NCT02389374). Between September 2014 and February 2015 a total of 181 patients were enrolled (64% P. falciparum, 30% P. vivax and 6% mixed infections). Median parasite clearance times were 22.0 (Interquartile Range, IQR: 15.2-27.3) hours for P. falciparum, 20.0 (IQR: 9.5-22.7) hours for P. vivax and 16.6 (IQR: 10.0-46.0) hours for mixed infections. All participants were afebrile within 48 hours, two patients with P. falciparum infection remained parasitemic at 48 hours. No patient had recurrent parasitaemia within 30 days. Adjusted male median G6PD activity was 7.82U/gHb. One male participant (1/174) had severe G6PD deficiency (<10% activity), five participants (5/174) had mild G6PD deficiency (10-60% activity). The Hb nadir occurred on day 2 prior to primaquine treatment in P. falciparum and P. vivax infected patients; mean fractional fall in Hb was -8.8% (95%CI -6.7% to -11.0%) and -7.4% (95%CI: -4.5 to -10.4%) respectively. The current antimalarial policy remains effective. The prevalence of G6PD deficiency was low. Main contribution to haemolysis in G6PD normal individuals was attributable to acute malaria rather than primaquine administration. ClinicalTrials.gov NCT02389374.

Therapeutic efficacy of alternative primaquine regimens to standard treatment in preventing relapses by Plasmodium vivax: A systematic review and meta-analysis.

PubMed

Zuluaga-Idarraga, Lina Marcela; Tamayo Perez, María-Eulalia; Aguirre-Acevedo, Daniel Camilo

2015-12-30

To compare efficacy and safety of primaquine regimens currently used to prevent relapses by P. vivax. A systematic review was carried out to identify clinical trials evaluating efficacy and safety to prevent malaria recurrences by P. vivax of primaquine regimen 0.5 mg/kg/ day for 7 or 14 days compared to standard regimen of 0.25 mg/kg/day for 14 days. Efficacy of primaquine according to cumulative incidence of recurrences after 28 days was determined. The overall relative risk with fixed-effects meta-analysis was estimated. For the regimen 0.5 mg/kg/day/7 days were identified 7 studies, which showed an incidence of recurrence between 0% and 20% with follow-up 60-210 days; only 4 studies comparing with the standard regimen 0.25 mg/kg/day/14 days and no difference in recurrences between both regimens (RR= 0.977, 95% CI= 0.670 to 1.423) were found. 3 clinical trials using regimen 0.5 mg/kg/day/14 days with an incidence of recurrences between 1.8% and 18.0% during 330-365 days were identified; only one study comparing with the standard regimen (RR= 0.846, 95% CI= 0.484 to 1.477). High risk of bias and differences in handling of included studies were found. Available evidence is insufficient to determine whether currently PQ regimens used as alternative rather than standard treatment have better efficacy and safety in preventing relapse of P. vivax. Clinical trials are required to guide changes in treatment regimen of malaria vivax.

Ferrocene-chloroquine analogues as antimalarial agents: in vitro activity of ferrochloroquine against 103 Gabonese isolates of Plasmodium falciparum.

PubMed

Pradines, B; Fusai, T; Daries, W; Laloge, V; Rogier, C; Millet, P; Panconi, E; Kombila, M; Parzy, D

2001-08-01

The in vitro activities of ferrochloroquine, chloroquine, quinine, mefloquine, halofantrine, amodiaquine, primaquine, atovaquone and artesunate were evaluated against Plasmodium falciparum isolates from children with uncomplicated malaria from Libreville (Gabon), using an isotopic, micro, drug susceptibility test. The IC(50) values for ferrochloroquine were in the range 0.43-30.9 nM and the geometric mean IC(50) for the 103 isolates was 10.8 nM (95% CI 8.6-13.5 nM), while the geometric means for chloroquine, quinine, mefloquine, amodiaquine and primaquine were 370 nM, 341 nM, 8.3 nM, 18.1 nM and 7.6 microM, respectively. Ferrochloroquine was active against P. falciparum isolates, 95% of which showed in vitro resistance to chloroquine. Weak positive significant correlations were observed between the responses to ferrochloroquine and that to chloroquine, amodiaquine and quinine, but too low to suggest cross-resistance. There was no significant correlation between the response to ferrochloroquine and those to mefloquine, halofantrine, primaquine, atovaquone or artesunate. Ferrochloroquine may be an important alternative drug for the treatment of chloroquine-resistant malaria.

Primaquine-induced haemolysis in females heterozygous for G6PD deficiency.

PubMed

Chu, Cindy S; Bancone, Germana; Nosten, François; White, Nicholas J; Luzzatto, Lucio

2018-03-02

Oxidative agents can cause acute haemolytic anaemia in persons with G6PD deficiency. Understanding the relationship between G6PD genotype and the phenotypic expression of the enzyme deficiency is necessary so that severe haemolysis can be avoided. The patterns of oxidative haemolysis have been well described in G6PD deficient hemizygous males and homozygous females; and haemolysis in the proportionally more numerous heterozygous females has been documented mainly following consumption of fava beans and more recently dapsone. It has long been known that 8-aminoquinolines, notably primaquine and tafenoquine, cause acute haemolysis in G6PD deficiency. To support wider use of primaquine in Plasmodium vivax elimination, more data are needed on the haemolytic consequences of 8-aminoquinolines in G6PD heterozygous females. Two recent studies (in 2017) have provided precisely such data; and the need has emerged for the development of point of care quantitative testing of G6PD activity. Another priority is exploring alternative 8-aminoquinoline dosing regimens that are practical and improve safety in G6PD deficient individuals.

Primaquine ineligibility in anti-relapse therapy of Plasmodium vivax malaria: the problem of G6PD deficiency and cytochrome P-450 2D6 polymorphisms.

PubMed

Baird, J Kevin; Battle, Katherine E; Howes, Rosalind E

2018-01-22

The hypnozoite reservoir of Plasmodium vivax represents both the greatest obstacle and opportunity for ultimately eradicating this species. It is silent and cannot be diagnosed until it awakens and provokes a clinical attack with attendant morbidity, risk of mortality, and opportunities for onward transmission. The only licensed drug that kills hypnozoites is primaquine, which attacks the hypnozoite reservoir but imposes serious obstacles in doing so-at hypnozoitocidal doses, it invariably causes a threatening acute haemolytic anaemia in patients having an inborn deficiency in glucose-6-phosphate dehydrogenase (G6PD), affecting about 8% of people living in malaria endemic nations. That problem excludes a large number of people from safe and effective treatment of the latent stage of vivax malaria: the G6PD deficient, pregnant or lactating women, and young infants. These groups were estimated to comprise 14.3% of populations resident in the 95 countries with endemic vivax malaria. Another important obstacle regarding primaquine in the business of killing hypnozoites is its apparent metabolism to an active metabolite exclusively via cytochrome P-450 isozyme 2D6 (CYP2D6). Natural polymorphisms of this allele create genotypes expressing impaired enzymes that occur in over 20% of people living in Southeast Asia, where more than half of P. vivax infections occur globally. Taken together, the estimated frequencies of these primaquine ineligibles due to G6PD toxicity or impaired CYP2D6 activity composed over 35% of the populations at risk of vivax malaria. Much more detailed work is needed to refine these estimates, derive probabilities of error for them, and improve their ethnographic granularity in order to inform control and elimination strategy and tactics.

Hemolytic Potential of Tafenoquine in Female Volunteers Heterozygous for Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency (G6PD Mahidol Variant) versus G6PD-Normal Volunteers.

PubMed

Rueangweerayut, Ronnatrai; Bancone, Germana; Harrell, Emma J; Beelen, Andrew P; Kongpatanakul, Supornchai; Möhrle, Jörg J; Rousell, Vicki; Mohamed, Khadeeja; Qureshi, Ammar; Narayan, Sushma; Yubon, Nushara; Miller, Ann; Nosten, François H; Luzzatto, Lucio; Duparc, Stephan; Kleim, Jörg-Peter; Green, Justin A

2017-09-01

Tafenoquine is an 8-aminoquinoline under investigation for the prevention of relapse in Plasmodium vivax malaria. This open-label, dose-escalation study assessed quantitatively the hemolytic risk with tafenoquine in female healthy volunteers heterozygous for the Mahidol 487A glucose-6-phosphate dehydrogenase (G6PD)-deficient variant versus G6PD-normal females, and with reference to primaquine. Six G6PD-heterozygous subjects (G6PD enzyme activity 40-60% of normal) and six G6PD-normal subjects per treatment group received single-dose tafenoquine (100, 200, or 300 mg) or primaquine (15 mg × 14 days). All participants had pretreatment hemoglobin levels ≥ 12.0 g/dL. Tafenoquine dose escalation stopped when hemoglobin decreased by ≥ 2.5 g/dL (or hematocrit decline ≥ 7.5%) versus pretreatment values in ≥ 3/6 subjects. A dose-response was evident in G6PD-heterozygous subjects ( N = 15) receiving tafenoquine for the maximum decrease in hemoglobin versus pretreatment values. Hemoglobin declines were similar for tafenoquine 300 mg (-2.65 to -2.95 g/dL [ N = 3]) and primaquine (-1.25 to -3.0 g/dL [ N = 5]). Two further cohorts of G6PD-heterozygous subjects with G6PD enzyme levels 61-80% ( N = 2) and > 80% ( N = 5) of the site median normal received tafenoquine 200 mg; hemolysis was less pronounced at higher G6PD enzyme activities. Tafenoquine hemolytic potential was dose dependent, and hemolysis was greater in G6PD-heterozygous females with lower G6PD enzyme activity levels. Single-dose tafenoquine 300 mg did not appear to increase the severity of hemolysis versus primaquine 15 mg × 14 days.

First Evaluation of Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency in Vivax Malaria Endemic Regions in the Republic of Korea

PubMed Central

Goo, Youn-Kyoung; Ji, So-Young; Shin, Hyun-Il; Moon, Jun-Hye; Cho, Shin-Hyung; Lee, Won-Ja; Kim, Jung-Yeon

2014-01-01

Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect and affects more than 400 million people worldwide. This deficiency is believed to protect against malaria because its global distribution is similar. However, this genetic disorder may be associated with potential hemolytic anemia after treatment with anti-malarials, primaquine or other 8-aminoquinolines. Although primaquine is used for malaria prevention, no study has previously investigated the prevalence of G6PD variants and G6PD deficiency in the Republic of Korea (ROK). Methods Two commercialized test kits (Trinity G-6-PDH and CareStart G6PD test) were used for G6PD deficiency screening. The seven common G6PD variants were investigated by DiaPlexC kit in blood samples obtained living in vivax malaria endemic regions in the ROK. Results Of 1,044 blood samples tested using the CareStart G6PD test, none were positive for G6PD deficiency. However, a slightly elevated level of G6PD activity was observed in 14 of 1,031 samples tested with the Trinity G-6-PDH test. Forty-nine of the 298 samples with non-specific amplification by DiaPlexC kit were confirmed by sequencing to be negative for the G6PD variants. Conclusions No G6PD deficiency was observed using phenotypic- or genetic-based tests in individuals residing in vivax malaria endemic regions in the ROK. Because massive chemoprophylaxis using primaquine has been performed in the ROK military to kill hypnozoites responsible for relapse and latent stage vivax malaria, further regular monitoring is essential for the safe administration of primaquine. PMID:24853873

First evaluation of glucose-6-phosphate dehydrogenase (G6PD) deficiency in vivax malaria endemic regions in the Republic of Korea.

PubMed

Goo, Youn-Kyoung; Ji, So-Young; Shin, Hyun-Il; Moon, Jun-Hye; Cho, Shin-Hyung; Lee, Won-Ja; Kim, Jung-Yeon

2014-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect and affects more than 400 million people worldwide. This deficiency is believed to protect against malaria because its global distribution is similar. However, this genetic disorder may be associated with potential hemolytic anemia after treatment with anti-malarials, primaquine or other 8-aminoquinolines. Although primaquine is used for malaria prevention, no study has previously investigated the prevalence of G6PD variants and G6PD deficiency in the Republic of Korea (ROK). Two commercialized test kits (Trinity G-6-PDH and CareStart G6PD test) were used for G6PD deficiency screening. The seven common G6PD variants were investigated by DiaPlexC kit in blood samples obtained living in vivax malaria endemic regions in the ROK. Of 1,044 blood samples tested using the CareStart G6PD test, none were positive for G6PD deficiency. However, a slightly elevated level of G6PD activity was observed in 14 of 1,031 samples tested with the Trinity G-6-PDH test. Forty-nine of the 298 samples with non-specific amplification by DiaPlexC kit were confirmed by sequencing to be negative for the G6PD variants. No G6PD deficiency was observed using phenotypic- or genetic-based tests in individuals residing in vivax malaria endemic regions in the ROK. Because massive chemoprophylaxis using primaquine has been performed in the ROK military to kill hypnozoites responsible for relapse and latent stage vivax malaria, further regular monitoring is essential for the safe administration of primaquine.

Malaria in Brazil, Colombia, Peru and Venezuela: current challenges in malaria control and elimination.

PubMed

Recht, Judith; Siqueira, André M; Monteiro, Wuelton M; Herrera, Sonia M; Herrera, Sócrates; Lacerda, Marcus V G

2017-07-04

In spite of significant progress towards malaria control and elimination achieved in South America in the 2000s, this mosquito-transmitted tropical disease remains an important public health concern in the region. Most malaria cases in South America come from Amazon rain forest areas in northern countries, where more than half of malaria is caused by Plasmodium vivax, while Plasmodium falciparum malaria incidence has decreased in recent years. This review discusses current malaria data, policies and challenges in four South American Amazon countries: Brazil, Colombia, Peru and the Bolivarian Republic of Venezuela. Challenges to continuing efforts to further decrease malaria incidence in this region include: a significant increase in malaria cases in recent years in Venezuela, evidence of submicroscopic and asymptomatic infections, peri-urban malaria, gold mining-related malaria, malaria in pregnancy, glucose-6-phosphate dehydrogenase (G6PD) deficiency and primaquine use, and possible under-detection of Plasmodium malariae. Some of these challenges underscore the need to implement appropriate tools and procedures in specific regions, such as a field-compatible molecular malaria test, a P. malariae-specific test, malaria diagnosis and appropriate treatment as part of regular antenatal care visits, G6PD test before primaquine administration for P. vivax cases (with weekly primaquine regimen for G6PD deficient individuals), single low dose of primaquine for P. falciparum malaria in Colombia, and national and regional efforts to contain malaria spread in Venezuela urgently needed especially in mining areas. Joint efforts and commitment towards malaria control and elimination should be strategized based on examples of successful regional malaria fighting initiatives, such as PAMAFRO and RAVREDA/AMI.

Extrahepatic exoerythrocytic forms of rodent malaria parasites at the site of inoculation: clearance after immunization, susceptibility to primaquine, and contribution to blood-stage infection.

PubMed

Voza, Tatiana; Miller, Jessica L; Kappe, Stefan H I; Sinnis, Photini

2012-06-01

Plasmodium sporozoites are inoculated into the skin of the mammalian host as infected mosquitoes probe for blood. A proportion of the inoculum enters the bloodstream and goes to the liver, where the sporozoites invade hepatocytes and develop into the next life cycle stage, the exoerythrocytic, or liver, stage. Here, we show that a small fraction of the inoculum remains in the skin and begins to develop into exoerythrocytic forms that can persist for days. Skin exoerythrocytic forms were observed for both Plasmodium berghei and Plasmodium yoelii, two different rodent malaria parasites, suggesting that development in the skin of the mammalian host may be a common property of plasmodia. Our studies demonstrate that skin exoerythrocytic stages are susceptible to destruction in immunized mice, suggesting that their aberrant location does not protect them from the host's adaptive immune response. However, in contrast to their hepatic counterparts, they are not susceptible to primaquine. We took advantage of their resistance to primaquine to test whether they could initiate a blood-stage infection directly from the inoculation site, and our data indicate that these stages are not able to initiate malaria infection.

G6PD deficiency alleles in a malaria-endemic region in the Western Brazilian Amazon.

PubMed

Dombrowski, Jamille G; Souza, Rodrigo M; Curry, Jonathan; Hinton, Laura; Silva, Natercia R M; Grignard, Lynn; Gonçalves, Ligia A; Gomes, Ana Rita; Epiphanio, Sabrina; Drakeley, Chris; Huggett, Jim; Clark, Taane G; Campino, Susana; Marinho, Claudio R F

2017-06-15

Plasmodium vivax parasites are the predominant cause of malaria infections in the Brazilian Amazon. Infected individuals are treated with primaquine, which can induce haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals and may lead to severe and fatal complications. This X-linked disorder is distributed globally and is caused by allelic variants with a geographical distribution that closely reflects populations exposed historically to endemic malaria. In Brazil, few studies have reported the frequency of G6PD deficiency (G6PDd) present in malaria-endemic areas. This is particularly important, as G6PDd screening is not currently performed before primaquine treatment. The aim of this study was to determine the prevalence of G6PDd in the region of Alto do Juruá, in the Western Brazilian Amazon, an area characterized by a high prevalence of P. vivax infection. Five-hundred and sixteen male volunteers were screened for G6PDd using the fluorescence spot test (Beutler test) and CareStart™ G6PD Biosensor system. Demographic and clinical-epidemiological data were acquired through an individual interview. To assess the genetic basis of G6PDd, 24 SNPs were genotyped using the Kompetitive Allele Specific PCR assay. Twenty-three (4.5%) individuals were G6PDd. No association was found between G6PDd and the number of malaria cases. An increased risk of reported haemolysis symptoms and blood transfusions was evident among the G6PDd individuals. Twenty-two individuals had the G6PDd A(-) variant and one the G6PD A(+) variant. The Mediterranean variant was not present. Apart from one polymorphism, almost all SNPs were monomorphic or with low frequencies (0-0.04%). No differences were detected among ethnic groups. The data indicates that ~1/23 males from the Alto do Juruá could be G6PD deficient and at risk of haemolytic anaemia if treated with primaquine. G6PD A(-) is the most frequent deficiency allele in this population. These results concur with reported G6PDd in other regions in Brazil. Routine G6PDd screening to personalize primaquine administration should be considered, particularly as complete treatment of patients with vivax malaria using chloroquine and primaquine, is crucial for malaria elimination.

Primaquine or other 8-aminoquinoline for reducing Plasmodium falciparum transmission

PubMed Central

Graves, Patricia M; Gelband, Hellen; Garner, Paul

2015-01-01

Background Mosquitoes become infected with Plasmodium when they ingest gametocyte-stage parasites from an infected person's blood. Plasmodium falciparum gametocytes are sensitive to the drug primaquine (PQ) and other 8-aminoquinolines (8AQ); these drugs could prevent parasite transmission from infected people to mosquitoes, and consequently reduce the incidence of malaria. However, PQ will not directly benefit the individual, and could be harmful to those with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In 2010, The World Health Organization (WHO) recommended a single dose of PQ at 0.75 mg/kg, alongside treatment for P. falciparum malaria to reduce transmission in areas approaching malaria elimination. In 2013 the WHO revised this to 0.25 mg/kg due to concerns about safety. Objectives To assess whether giving PQ or an alternative 8AQ alongside treatment for P. falciparum malaria reduces malaria transmission, and to estimate the frequency of severe or haematological adverse events when PQ is given for this purpose. Search methods We searched the following databases up to 10 Feb 2014 for trials: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; metaRegister of Controlled Trials (mRCT); and the WHO trials search portal using 'malaria*', 'falciparum', and 'primaquine' as search terms. In addition, we searched conference proceedings and reference lists of included studies, and contacted researchers and organizations. Selection criteria Randomized controlled trials (RCTs) or quasi-RCTs comparing PQ (or alternative 8AQ) given as a single dose or short course alongside treatment for P. falciparum malaria with malaria treatment given without PQ/8AQ in adults or children. Data collection and analysis Two authors independently screened all abstracts, applied inclusion criteria, and extracted data. We sought evidence of an impact on transmission (community incidence), infectiousness (mosquitoes infected from humans) and potential infectiousness (gametocyte measures). We calculated the area under the curve (AUC) for gametocyte density over time for comparisons for which data were available. We sought data on haematological and other adverse effects, as well as secondary outcomes of asexual clearance time and recrudescence. We stratified by whether the malaria treatment regimen included an artemisinin derivative or not; by PQ dose category (low < 0.4 mg/kg; medium ≥ 0.4 to < 0.6 mg/kg; high ≥ 0.6 mg/kg); and by PQ schedules. We used the GRADE approach to assess evidence quality. Main results We included 17 RCTs and one quasi-RCT. Eight studies tested for G6PD status: six then excluded participants with G6PD deficiency, one included only those with G6PD deficiency, and one included all irrespective of status. The remaining ten trials either did not report on whether they tested (8), or reported that they did not test (2). Nine trials included study arms with artemisinin-based malaria treatment regimens, and eleven included study arms with non-artemisinin-based treatments. Only two trials evaluated PQ given at low doses (0.25 mg/kg in one and 0.1 mg/kg in the other). PQ with artemisinin-based treatments: No trials evaluated effects on malaria transmission directly (incidence, prevalence, or entomological inoculation rate), and none evaluated infectiousness to mosquitoes. For potential infectiousness, the proportion of people with detectable gametocytaemia on day eight was reduced by around two thirds with high dose PQ category (RR 0.29, 95% CI 0.22 to 0.37, seven trials, 1380 participants, high quality evidence), and with medium dose PQ category (RR 0.34, 95% CI 0.19 to 0.59, two trials, 269 participants, high quality evidence), but the trial evaluating low dose PQ category (0.1 mg/kg) did not demonstrate an effect (RR 0.67, 95% CI 0.44 to 1.02, one trial, 223 participants, low quality evidence). Reductions in log(10)AUC estimates for gametocytaemia on days 1 to 43 with medium and high doses ranged from 24.3% to 87.5%. For haemolysis, one trial reported percent change in mean haemoglobin against baseline, and did not detect a difference between the two arms (very low quality evidence). PQ with non-artemisinin treatments: No trials assessed effects on malaria transmission directly. Two small trials from the same laboratory evaluated infectiousness to mosquitoes, and report that infectivity was eliminated on day 8 in 15/15 patients receiving high dose PQ compared to 1/15 in the control group (low quality evidence). For potential infectiousness, the proportion of people with detectable gametocytaemia on day 8 was reduced by around half with high dose PQ category (RR 0.44, 95% CI 0.27 to 0.70, three trials, 206 participants, high quality evidence), and by around a third with medium dose category (RR 0.62, 0.50 to 0.76, two trials, 283 participants, high quality evidence), but the single trial using low dose PQ category did not demonstrate a difference between groups (one trial, 59 participants, very low quality evidence). Reduction in log(10)AUC for gametocytaemia days 1 to 43 were 24.3% and 27.1% for two arms in one trial giving medium dose PQ. No trials systematically sought evidence of haemolysis. Two trials evaluated the 8AQ bulaquine, and suggest the effects may be greater than PQ, but the small number of participants (n = 112) preclude a definite conclusion. Authors' conclusions In individual patients, PQ added to malaria treatments reduces gametocyte prevalence when given in doses greater than 0.4 mg/kg. Whether this translates into preventing people transmitting malaria to mosquitoes has rarely been tested in controlled trials, but there appeared to be a strong reduction in infectiousness in the two small studies that evaluated this. No included trials evaluated whether this policy has an impact on community malaria transmission either in low-endemic settings approaching elimination, or in highly-endemic settings where many people are infected but have no symptoms and are unlikely to be treated. For the currently recommended low dose regimen, there is little direct evidence to be confident that the effect of reduction in gametocyte prevalence is preserved. Most trials excluded people with G6PD deficiency, and thus there is little reliable evidence from controlled trials of the safety of PQ in single dose or short course. PLAIN LANGUAGE SUMMARY A single dose of primaquine added to malaria treatment to prevent malaria transmission We conducted a review of the effects of adding a single dose (or short course) of primaquine to malaria treatment with the aim of reducing the transmission of malaria. We included 17 randomized controlled trials and one quasi-randomized controlled trial. What is primaquine and how might it reduce transmission Primaquine is an antimalarial drug which does not cure malaria illness, but is known to kill the gametocyte stage of the malaria parasite which infects mosquitoes when they bite humans. Primaquine is also known to have potentially serious side effects in people with an enzyme deficiency common in many malaria endemic settings (glucose-6-phosphate dehydrogenase (G6PD) deficiency). In these people, high doses of primaquine given over several days sometimes destroys red blood cells, causing anaemia and, in some cases, possibly life-threatening effects. The World Health Organization (WHO) recommends adding a single dose of primaquine to malaria treatment with the intention of reducing malaria transmission and to contribute to malaria elimination. This recommendation was made in 2010, but in 2013 the WHO amended its recommendation from a dose of 0.75 mg/kg to 0.25 mg/kg due to concerns about safety, and indirect evidence suggesting this was as effective as the higher dose.This review examines the evidence of benefits and harms of using primaquine in this way, and looks for evidence that primaquine will reduce malaria transmission in communities. What the research says We did not find any studies that tested whether primaquine added to malaria treatment reduces the community transmission of malaria. When added to current treatments for malaria (artemisinin-based combination therapy), we found no studies evaluating the effects of primaquine on the number of mosquitoes infected. However, primaquine does reduce the duration of infectiousness (the period that gametocytes are detected circulating in the blood) when given at doses of 0.4 mg/kg or above (high quality evidence). We only found one study using 0.1 mg/kg but this study did not conclusively show that primaquine was still effective at this dose (low quality evidence). When added to older treatments for malaria, two studies showed that primaquine at doses of 0.75 mg/kg reduced the number of mosquitoes infected after biting humans (low quality evidence). Doses above 0.4 mg/kg reduced the duration of detectable gametocytes (high quality evidence), but in a single study of the currently recommended 0.25 mg/kg no effect was demonstrated (very low quality evidence). Some studies excluded patients with G6PD deficiency, some included them, and some did not comment. Overall the safety of PQ given as a single dose was poorly evaluated across all studies, so these data do not demonstrate whether the drug is safe or potentially harmful at this dosing level. PMID:25693791

Primaquine or other 8-aminoquinoline for reducing P. falciparum transmission

PubMed Central

Graves, Patricia M; Gelband, Hellen; Garner, Paul

2014-01-01

Background Mosquitoes become infected with Plasmodium when they ingest gametocyte-stage parasites from an infected person's blood. Plasmodium falciparum gametocytes are sensitive to the drug primaquine (PQ) and other 8-aminoquinolines (8AQ); these drugs could prevent parasite transmission from infected people to mosquitoes, and consequently reduce the incidence of malaria. However, PQ will not directly benefit the individual, and could be harmful to those with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In 2010, The World Health Organization (WHO) recommended a single dose of PQ at 0.75 mg/kg, alongside treatment for P. falciparum malaria to reduce transmission in areas approaching malaria elimination. In 2013 the WHO revised this to 0.25 mg/kg due to concerns about safety. Objectives To assess whether giving PQ or an alternative 8AQ alongside treatment for P. falciparum malaria reduces malaria transmission, and to estimate the frequency of severe or haematological adverse events when PQ is given for this purpose. Search methods We searched the following databases up to 10 Feb 2014 for trials: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; metaRegister of Controlled Trials (mRCT); and the WHO trials search portal using 'malaria*', 'falciparum', and 'primaquine' as search terms. In addition, we searched conference proceedings and reference lists of included studies, and contacted researchers and organizations. Selection criteria Randomized controlled trials (RCTs) or quasi-RCTs comparing PQ (or alternative 8AQ) given as a single dose or short course alongside treatment for P. falciparum malaria with malaria treatment given without PQ/8AQ in adults or children. Data collection and analysis Two authors independently screened all abstracts, applied inclusion criteria, and extracted data. We sought evidence of an impact on transmission (community incidence), infectiousness (mosquitoes infected from humans) and potential infectiousness (gametocyte measures). We calculated the area under the curve (AUC) for gametocyte density over time for comparisons for which data were available. We sought data on haematological and other adverse effects, as well as secondary outcomes of asexual clearance time and recrudescence. We stratified by whether the malaria treatment regimen included an artemisinin derivative or not; by PQ dose category (low < 0.4 mg/kg; medium ≥ 0.4 to < 0.6 mg/kg; high ≥ 0.6 mg/kg); and by PQ schedules. We used the GRADE approach to assess evidence quality. Main results We included 17 RCTs and one quasi-RCT. Eight studies tested for G6PD status: six then excluded participants with G6PD deficiency, one included only those with G6PD deficiency, and one included all irrespective of status. The remaining ten trials either did not report on whether they tested (8), or reported that they did not test (2). Nine trials included study arms with artemisinin-based malaria treatment regimens, and eleven included study arms with non-artemisinin-based treatments. Only two trials evaluated PQ given at low doses (0.25 mg/kg in one and 0.1 mg/kg in the other). PQ with artemisinin-based treatments: No trials evaluated effects on malaria transmission directly (incidence, prevalence, or entomological inoculation rate), and none evaluated infectiousness to mosquitoes. For potential infectiousness, the proportion of people with detectable gametocytaemia on day eight was reduced by around two thirds with high dose PQ category (RR 0.29, 95% CI 0.22 to 0.37, seven trials, 1380 participants, high quality evidence), and with medium dose PQ category (RR 0.34, 95% CI 0.19 to 0.59, two trials, 269 participants, high quality evidence), but the trial evaluating low dose PQ category (0.1 mg/kg) did not demonstrate an effect (RR 0.67, 95% CI 0.44 to 1.02, one trial, 223 participants, low quality evidence). Reductions in log(10)AUC estimates for gametocytaemia on days 1 to 43 with medium and high doses ranged from 24.3% to 87.5%. For haemolysis, one trial reported percent change in mean haemoglobin against baseline, and did not detect a difference between the two arms (very low quality evidence). PQ with non-artemisinin treatments: No trials assessed effects on malaria transmission directly. Two small trials from the same laboratory evaluated infectiousness to mosquitoes, and report that infectivity was eliminated on day 8 in 15/15 patients receiving high dose PQ compared to 1/15 in the control group (low quality evidence). For potential infectiousness, the proportion of people with detectable gametocytaemia on day 8 was reduced by around half with high dose PQ category (RR 0.44, 95% CI 0.27 to 0.70, three trials, 206 participants, high quality evidence), and by around a third with medium dose category (RR 0.62, 0.50 to 0.76, two trials, 283 participants, high quality evidence), but the single trial using low dose PQ category did not demonstrate a difference between groups (one trial, 59 participants, very low quality evidence). Reduction in log(10)AUC for gametocytaemia days 1 to 43 were 24.3% and 27.1% for two arms in one trial giving medium dose PQ. No trials systematically sought evidence of haemolysis. Two trials evaluated the 8AQ bulaquine, and suggest the effects may be greater than PQ, but the small number of participants (n = 112) preclude a definite conclusion. Authors' conclusions In individual patients, PQ added to malaria treatments reduces gametocyte prevalence when given in doses greater than 0.4 mg/kg. Whether this translates into preventing people transmitting malaria to mosquitoes has rarely been tested in controlled trials, but there appeared to be a strong reduction in infectiousness in the two small studies that evaluated this. No included trials evaluated whether this policy has an impact on community malaria transmission either in low-endemic settings approaching elimination, or in highly-endemic settings where many people are infected but have no symptoms and are unlikely to be treated. For the currently recommended low dose regimen, there is little direct evidence to be confident that the effect of reduction in gametocyte prevalence is preserved. Most trials excluded people with G6PD deficiency, and thus there is little reliable evidence from controlled trials of the safety of PQ in single dose or short course. PLAIN LANGUAGE SUMMARY A single dose of primaquine added to malaria treatment to prevent malaria transmission We conducted a review of the effects of adding a single dose (or short course) of primaquine to malaria treatment with the aim of reducing the transmission of malaria. We included 17 randomized controlled trials and one quasi-randomized controlled trial. What is primaquine and how might it reduce transmission Primaquine is an antimalarial drug which does not cure malaria illness, but is known to kill the gametocyte stage of the malaria parasite which infects mosquitoes when they bite humans. Primaquine is also known to have potentially serious side effects in people with an enzyme deficiency common in many malaria endemic settings (glucose-6-phosphate dehydrogenase (G6PD) deficiency). In these people, high doses of primaquine given over several days sometimes destroys red blood cells, causing anaemia and, in some cases, possibly life-threatening effects. The World Health Organization (WHO) recommends adding a single dose of primaquine to malaria treatment with the intention of reducing malaria transmission and to contribute to malaria elimination. This recommendation was made in 2010, but in 2013 the WHO amended its recommendation from a dose of 0.75 mg/kg to 0.25 mg/kg due to concerns about safety, and indirect evidence suggesting this was as effective as the higher dose.This review examines the evidence of benefits and harms of using primaquine in this way, and looks for evidence that primaquine will reduce malaria transmission in communities. What the research says We did not find any studies that tested whether primaquine added to malaria treatment reduces the community transmission of malaria. When added to current treatments for malaria (artemisinin-based combination therapy), we found no studies evaluating the effects of primaquine on the number of mosquitoes infected. However, primaquine does reduce the duration of infectiousness (the period that gametocytes are detected circulating in the blood) when given at doses of 0.4 mg/kg or above (high quality evidence). We only found one study using 0.1 mg/kg but this study did not conclusively show that primaquine was still effective at this dose (low quality evidence). When added to older treatments for malaria, two studies showed that primaquine at doses of 0.75 mg/kg reduced the number of mosquitoes infected after biting humans (low quality evidence). Doses above 0.4 mg/kg reduced the duration of detectable gametocytes (high quality evidence), but in a single study of the currently recommended 0.25 mg/kg no effect was demonstrated (very low quality evidence). Some studies excluded patients with G6PD deficiency, some included them, and some did not comment. Overall the safety of PQ given as a single dose was poorly evaluated across all studies, so these data do not demonstrate whether the drug is safe or potentially harmful at this dosing level. PMID:24979199

Glucose-6-phosphate dehydrogenase deficiency among malaria patients of Honduras: a descriptive study of archival blood samples.

PubMed

Zúñiga, Miguel Á; Mejía, Rosa E; Sánchez, Ana L; Sosa-Ochoa, Wilfredo H; Fontecha, Gustavo A

2015-08-07

The frequency of deficient variants of glucose-6-phosphate dehydrogenase (G6PDd) is particularly high in areas where malaria is endemic. The administration of antirelapse drugs, such as primaquine, has the potential to trigger an oxidative event in G6PD-deficient individuals. According to Honduras´ national scheme, malaria treatment requires the administration of chloroquine and primaquine for both Plasmodium vivax and Plasmodium falciparum infections. The present study aimed at investigating for the first time in Honduras the frequency of the two most common G6PDd variants. This was a descriptive study utilizing 398 archival DNA samples of patients that had been diagnosed with malaria due to P. vivax, P. falciparum, or both. The most common allelic variants of G6PD: G6PD A+(376G) and G6PD A-(376G/202A) were assessed by two molecular methods (PCR-RFLP and a commercial kit). The overall frequency of G6PD deficient genotypes was 16.08%. The frequency of the "African" genotype A- (Class III) was 11.9% (4.1% A- hemizygous males; 1.5% homozygous A- females; and 6.3% heterozygous A- females). A high frequency of G6PDd alleles was observed in samples from malaria patients residing in endemic regions of Northern Honduras. One case of Santamaria mutation (376G/542T) was detected. Compared to other studies in the Americas, as well as to data from predictive models, the present study identified a higher-than expected frequency of genotype A- in Honduras. Considering that the national standard of malaria treatment in the country includes primaquine, further research is necessary to ascertain the risk of PQ-triggered haemolytic reactions in sectors of the population more likely to carry G6PD mutations. Additionally, consideration should be given to utilizing point of care technologies to detect this genetic disorder prior administration of 8-aminoquinoline drugs, either primaquine or any new drug available in the near future.

Quality of antimalarial drugs and antibiotics in Papua New Guinea: a survey of the health facility supply chain.

PubMed

Hetzel, Manuel W; Page-Sharp, Madhu; Bala, Nancy; Pulford, Justin; Betuela, Inoni; Davis, Timothy M E; Lavu, Evelyn K

2014-01-01

Poor-quality life-saving medicines are a major public health threat, particularly in settings with a weak regulatory environment. Insufficient amounts of active pharmaceutical ingredients (API) endanger patient safety and may contribute to the development of drug resistance. In the case of malaria, concerns relate to implications for the efficacy of artemisinin-based combination therapies (ACT). In Papua New Guinea (PNG), Plasmodium falciparum and P. vivax are both endemic and health facilities are the main source of treatment. ACT has been introduced as first-line treatment but other drugs, such as primaquine for the treatment of P. vivax hypnozoites, are widely available. This study investigated the quality of antimalarial drugs and selected antibiotics at all levels of the health facility supply chain in PNG. Medicines were obtained from randomly sampled health facilities and selected warehouses and hospitals across PNG and analysed for API content using validated high performance liquid chromatography (HPLC). Of 360 tablet/capsule samples from 60 providers, 9.7% (95% CI 6.9, 13.3) contained less, and 0.6% more, API than pharmacopoeial reference ranges, including 29/37 (78.4%) primaquine, 3/70 (4.3%) amodiaquine, and one sample each of quinine, artemether, sulphadoxine-pyrimethamine and amoxicillin. According to the package label, 86.5% of poor-quality samples originated from India. Poor-quality medicines were found in 48.3% of providers at all levels of the supply chain. Drug quality was unrelated to storage conditions. This study documents the presence of poor-quality medicines, particularly primaquine, throughout PNG. Primaquine is the only available transmission-blocking antimalarial, likely to become important to prevent the spread of artemisinin-resistant P. falciparum and eliminating P. vivax hypnozoites. The availability of poor-quality medicines reflects the lack of adequate quality control and regulatory mechanisms. Measures to stop the availability of poor-quality medicines should include limiting procurement to WHO prequalified products and implementing routine quality testing.

Quality of Antimalarial Drugs and Antibiotics in Papua New Guinea: A Survey of the Health Facility Supply Chain

PubMed Central

Hetzel, Manuel W.; Page-Sharp, Madhu; Bala, Nancy; Pulford, Justin; Betuela, Inoni; Davis, Timothy M. E.; Lavu, Evelyn K.

2014-01-01

Background Poor-quality life-saving medicines are a major public health threat, particularly in settings with a weak regulatory environment. Insufficient amounts of active pharmaceutical ingredients (API) endanger patient safety and may contribute to the development of drug resistance. In the case of malaria, concerns relate to implications for the efficacy of artemisinin-based combination therapies (ACT). In Papua New Guinea (PNG), Plasmodium falciparum and P. vivax are both endemic and health facilities are the main source of treatment. ACT has been introduced as first-line treatment but other drugs, such as primaquine for the treatment of P. vivax hypnozoites, are widely available. This study investigated the quality of antimalarial drugs and selected antibiotics at all levels of the health facility supply chain in PNG. Methods and Findings Medicines were obtained from randomly sampled health facilities and selected warehouses and hospitals across PNG and analysed for API content using validated high performance liquid chromatography (HPLC). Of 360 tablet/capsule samples from 60 providers, 9.7% (95% CI 6.9, 13.3) contained less, and 0.6% more, API than pharmacopoeial reference ranges, including 29/37 (78.4%) primaquine, 3/70 (4.3%) amodiaquine, and one sample each of quinine, artemether, sulphadoxine-pyrimethamine and amoxicillin. According to the package label, 86.5% of poor-quality samples originated from India. Poor-quality medicines were found in 48.3% of providers at all levels of the supply chain. Drug quality was unrelated to storage conditions. Conclusions This study documents the presence of poor-quality medicines, particularly primaquine, throughout PNG. Primaquine is the only available transmission-blocking antimalarial, likely to become important to prevent the spread of artemisinin-resistant P. falciparum and eliminating P. vivax hypnozoites. The availability of poor-quality medicines reflects the lack of adequate quality control and regulatory mechanisms. Measures to stop the availability of poor-quality medicines should include limiting procurement to WHO prequalified products and implementing routine quality testing. PMID:24828338

Hemolytic Potential of Tafenoquine in Female Volunteers Heterozygous for Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency (G6PD Mahidol Variant) versus G6PD-Normal Volunteers

PubMed Central

Rueangweerayut, Ronnatrai; Bancone, Germana; Harrell, Emma J.; Beelen, Andrew P.; Kongpatanakul, Supornchai; Möhrle, Jörg J.; Rousell, Vicki; Mohamed, Khadeeja; Qureshi, Ammar; Narayan, Sushma; Yubon, Nushara; Miller, Ann; Nosten, François H.; Luzzatto, Lucio; Duparc, Stephan; Kleim, Jörg-Peter; Green, Justin A.

2017-01-01

Abstract. Tafenoquine is an 8-aminoquinoline under investigation for the prevention of relapse in Plasmodium vivax malaria. This open-label, dose-escalation study assessed quantitatively the hemolytic risk with tafenoquine in female healthy volunteers heterozygous for the Mahidol487A glucose-6-phosphate dehydrogenase (G6PD)-deficient variant versus G6PD-normal females, and with reference to primaquine. Six G6PD-heterozygous subjects (G6PD enzyme activity 40–60% of normal) and six G6PD-normal subjects per treatment group received single-dose tafenoquine (100, 200, or 300 mg) or primaquine (15 mg × 14 days). All participants had pretreatment hemoglobin levels ≥ 12.0 g/dL. Tafenoquine dose escalation stopped when hemoglobin decreased by ≥ 2.5 g/dL (or hematocrit decline ≥ 7.5%) versus pretreatment values in ≥ 3/6 subjects. A dose–response was evident in G6PD-heterozygous subjects (N = 15) receiving tafenoquine for the maximum decrease in hemoglobin versus pretreatment values. Hemoglobin declines were similar for tafenoquine 300 mg (−2.65 to −2.95 g/dL [N = 3]) and primaquine (−1.25 to −3.0 g/dL [N = 5]). Two further cohorts of G6PD-heterozygous subjects with G6PD enzyme levels 61–80% (N = 2) and > 80% (N = 5) of the site median normal received tafenoquine 200 mg; hemolysis was less pronounced at higher G6PD enzyme activities. Tafenoquine hemolytic potential was dose dependent, and hemolysis was greater in G6PD-heterozygous females with lower G6PD enzyme activity levels. Single-dose tafenoquine 300 mg did not appear to increase the severity of hemolysis versus primaquine 15 mg × 14 days. PMID:28749773

Plasmodium vivax malaria relapses at a travel medicine centre in Rio de Janeiro, a non-endemic area in Brazil

PubMed Central

2012-01-01

Background Malaria is a potentially severe disease widely distributed in tropical and subtropical regions worldwide. Clinically, the progression of the disease can be life-threatening if it is not promptly diagnosed and properly treated. Through treatment, the radical cure of Plasmodium vivax infection can be achieved, thus preventing potential relapses and the emergence of new cases outside the Amazon region in Brazil. Surveillance for therapeutic failure in non-endemic areas is advantageous, as it is unlikely that recurrence of the disease can be attributed to a new malaria infection in these regions. Methods An observational study of 53 cases of P. vivax and mixed (P. vivax and Plasmodium falciparum) malaria was conducted at a travel medicine centre between 2005 and 2011 in Rio de Janeiro and a descriptive analysis of the potential factors related to recurrence of P. vivax malaria was performed. Groups with different therapeutic responses were compared using survival analysis based on the length of time to recurrence and a set of independent variables thought to be associated with recurrence. Results Twenty-one relapses (39.6%) of P. vivax malaria were observed. The overall median time to relapse, obtained by the Kaplan-Meier method, was 108 days, and the survival analysis demonstrated an association between non-weight-adjusted primaquine dosing and the occurrence of relapse (p < 0.03). Primaquine total dose at 3.6 mg/kg gave improved results in preventing relapses. Conclusions A known challenge to individual cure and environmental control of malaria is the possibility of an inappropriate, non-weight-based primaquine dosing, which should be considered a potential cause of P. vivax malaria relapse. Indeed, the total dose of primaquine associated with non-occurrence of relapses was higher than recommended by Brazilian guidelines. PMID:22839416

Implementation of G6PD testing and primaquine for P. vivax radical cure: Operational perspectives from Thailand and Cambodia.

PubMed

Kitchakarn, Suravadee; Lek, Dysoley; Thol, Sea; Hok, Chantheasy; Saejeng, Aungkana; Huy, Rekol; Chinanonwait, Nipon; Thimasarn, Krongthong; Wongsrichanalai, Chansuda

2017-09-01

Following progressive success in reducing the burden of malaria over the past two decades, countries of the Asia Pacific are now aiming for elimination of malaria by 2030. Plasmodium falciparum and Plasmodium vivax are the two main malaria species that are endemic in the region. P. vivax is generally perceived to be less severe but will be harder to eliminate, owing partly to its dormant liver stage (known as a hypnozoite) that can cause multiple relapses following an initial clinical episode caused by a mosquito-borne infection. Primaquine is the only anti-hypnozoite drug against P. vivax relapse currently available, with tafenoquine in the pipeline. However, both drugs may cause severe haemolysis in individuals with deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), a hereditary defect. The overall incidence of malaria has significantly declined in both Thailand and Cambodia over the last 15 years. However, P. vivax has replaced P. falciparum as the dominant species in large parts of both countries. This paper presents the experience of the national malaria control programmes of the two countries, in their efforts to implement safe primaquine therapy for the radical cure, i.e. relapse prevention, of P. vivax malaria by introducing a rapid, point-of-care test to screen for G6PD deficiency.

Dapsone Topical

MedlinePlus

... as phenytoin (Dilantin, Phenytek); antimalarial medications such as chloroquine (Aralen), primaquine, and quinine (Qualaquin); dapsone (by mouth); ... and the laboratory.Do not let anyone else use your medication. Ask your pharmacist any questions you ...

Carl Jung.

PubMed

Kyle, R A; Shampo, M A

1978-11-17

Physicians should be prepared to provide prophylactic medications for travelers to malarious areas and to treat patients with malaria. Chloroquine hydrochloride is the suppressive agent of choice for treatment of mild infections due to all species of malaria except for those due to chloroquine-resistant strains of Plasmodium falciparum. For treatment of severe infections with P falciparum and for treatment of all infections due to chloroquine-resistant strains of P falciparum quinine is the suppressive agent of choice. Chloroquine is also the prophylactic agent of choice for most travelers. To prevent infection with P vivax or P ovale, primaquine must also be given. A RBC glucose-6-phosphate dehydrogenase level should be obtained before administration of primaquine. For prophylaxis of chloroquine-resistant strains of P falciparum, no completely satisfactory regime is presently available in the United States.

Assessment of Point-of-Care Diagnostics for G6PD Deficiency in Malaria Endemic Rural Eastern Indonesia

PubMed Central

Satyagraha, Ari W.; Sadhewa, Arkasha; Elvira, Rosalie; Elyazar, Iqbal; Feriandika, Denny; Antonjaya, Ungke; Oyong, Damian; Subekti, Decy; Rozi, Ismail E.; Domingo, Gonzalo J.; Harahap, Alida R.; Baird, J. Kevin

2016-01-01

Background Patients infected by Plasmodium vivax or Plasmodium ovale suffer repeated clinical attacks without primaquine therapy against latent stages in liver. Primaquine causes seriously threatening acute hemolytic anemia in patients having inherited glucose-6-phosphate dehydrogenase (G6PD) deficiency. Access to safe primaquine therapy hinges upon the ability to confirm G6PD normal status. CareStart G6PD, a qualitative G6PD rapid diagnostic test (G6PD RDT) intended for use at point-of-care in impoverished rural settings where most malaria patients live, was evaluated. Methodology/Principal Findings This device and the standard qualitative fluorescent spot test (FST) were each compared against the quantitative spectrophotometric assay for G6PD activity as the diagnostic gold standard. The assessment occurred at meso-endemic Panenggo Ede in western Sumba Island in eastern Indonesia, where 610 residents provided venous blood. The G6PD RDT and FST qualitative assessments were performed in the field, whereas the quantitative assay was performed in a research laboratory at Jakarta. The median G6PD activity ≥5 U/gHb was 9.7 U/gHb and was considered 100% of normal activity. The prevalence of G6PD deficiency by quantitative assessment (<5 U/gHb) was 7.2%. Applying 30% of normal G6PD activity as the cut-off for qualitative testing, the sensitivity, specificity, positive predictive value, and negative predictive value for G6PD RDT versus FST among males were as follows: 100%, 98.7%, 89%, and 100% versus 91.7%, 92%, 55%, and 99%; P = 0.49, 0.001, 0.004, and 0.24, respectively. These values among females were: 83%, 92.7%, 17%, and 99.7% versus 100%, 92%, 18%, and 100%; P = 1.0, 0.89, 1.0 and 1.0, respectively. Conclusions/Significance The overall performance of G6PD RDT, especially 100% negative predictive value, demonstrates suitable safety for G6PD screening prior to administering hemolytic drugs like primaquine and many others. Relatively poor diagnostic performance among females due to mosaic G6PD phenotype is an inherent limitation of any current practical screening methodology. PMID:26894297

Assessment of Point-of-Care Diagnostics for G6PD Deficiency in Malaria Endemic Rural Eastern Indonesia.

PubMed

Satyagraha, Ari W; Sadhewa, Arkasha; Elvira, Rosalie; Elyazar, Iqbal; Feriandika, Denny; Antonjaya, Ungke; Oyong, Damian; Subekti, Decy; Rozi, Ismail E; Domingo, Gonzalo J; Harahap, Alida R; Baird, J Kevin

2016-02-01

Patients infected by Plasmodium vivax or Plasmodium ovale suffer repeated clinical attacks without primaquine therapy against latent stages in liver. Primaquine causes seriously threatening acute hemolytic anemia in patients having inherited glucose-6-phosphate dehydrogenase (G6PD) deficiency. Access to safe primaquine therapy hinges upon the ability to confirm G6PD normal status. CareStart G6PD, a qualitative G6PD rapid diagnostic test (G6PD RDT) intended for use at point-of-care in impoverished rural settings where most malaria patients live, was evaluated. This device and the standard qualitative fluorescent spot test (FST) were each compared against the quantitative spectrophotometric assay for G6PD activity as the diagnostic gold standard. The assessment occurred at meso-endemic Panenggo Ede in western Sumba Island in eastern Indonesia, where 610 residents provided venous blood. The G6PD RDT and FST qualitative assessments were performed in the field, whereas the quantitative assay was performed in a research laboratory at Jakarta. The median G6PD activity ≥ 5 U/gHb was 9.7 U/gHb and was considered 100% of normal activity. The prevalence of G6PD deficiency by quantitative assessment (<5 U/gHb) was 7.2%. Applying 30% of normal G6PD activity as the cut-off for qualitative testing, the sensitivity, specificity, positive predictive value, and negative predictive value for G6PD RDT versus FST among males were as follows: 100%, 98.7%, 89%, and 100% versus 91.7%, 92%, 55%, and 99%; P = 0.49, 0.001, 0.004, and 0.24, respectively. These values among females were: 83%, 92.7%, 17%, and 99.7% versus 100%, 92%, 18%, and 100%; P = 1.0, 0.89, 1.0 and 1.0, respectively. The overall performance of G6PD RDT, especially 100% negative predictive value, demonstrates suitable safety for G6PD screening prior to administering hemolytic drugs like primaquine and many others. Relatively poor diagnostic performance among females due to mosaic G6PD phenotype is an inherent limitation of any current practical screening methodology.

Blood schizontocidal activity of WR 238605 (Tafenoquine) against Plasmodium cynomolgi and Plasmodium fragile infections in rhesus monkeys.

PubMed

Puri, S K; Dutta, G P

2003-04-01

A new 8-aminoquinoline antimalarial WR 238605 (Tafenoquine), developed initially as a primaquine alternative for prevention of Plasmodium vivax relapses was evaluated for blood schizontocidal activity against two simian malaria infections namely Plasmodium cynomolgi B and Plasmodium fragile in rhesus monkeys. Treatment with WR 238605 at a dose of 3.16 mg(base)/kg/day x 7 days cured established trophozoite induced infections in monkeys with both these parasites. The lower dose of 1.00 mg/kg/day cured 9 out of 12 monkeys infected with P. cynomolgi B and 10 out of 11 monkeys infected with P. fragile. Primaquine was only partially curative at 10.0 mg(base)/kg/day x 7 dose regimen against both these infections. The potent blood schizontocidal activity of tafenoquine adds to the armoury of antimalarial drugs.

Safety of 8-aminoquinolines given to people with G6PD deficiency: protocol for systematic review of prospective studies

PubMed Central

Uthman, Olalekan A; Saunders, Rachel; Sinclair, David; Graves, Patricia; Gelband, Hellen; Clarke, Aileen; Garner, Paul

2014-01-01

Introduction A single dose or short course of primaquine given to people infected with malaria may reduce transmission of Plasmodium falciparum through its effects on gametocytes. Primaquine is also known to cause haemolysis in people with variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency. The objective of this systematic review was to assess the risk of adverse effects in people with G6PD deficiency given primaquine or other 8-aminoquinoline (8AQ) as a single dose or short course (less than 7 days). Methods and analysis We will search the following databases: Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and LILACS. Prospective cohort studies, randomised and quasi-randomised trials that evaluated 8AQs for whatever reason in adults or children with a known G6PD deficiency will be included. Two authors will independently assess each study for eligibility, risk of bias and extract data. Ethics and dissemination This systematic review will be published in a peer-reviewed journal. Brief reports of the review findings will be disseminated directly to the appropriate audiences and the WHO Technical Expert Group in Malaria Chemotherapy. As no primary data collection will be undertaken, no additional formal ethical assessment and informed consent are required. Protocol registration in PROSPERO The protocol is registered with PROSPERO, registration number CRD42013006518. PMID:24833685

Prospective Study of Plasmodium vivax Malaria Recurrence after Radical Treatment with a Chloroquine-Primaquine Standard Regimen in Turbo, Colombia

PubMed Central

Blair, Silvia; Akinyi Okoth, Sheila; Udhayakumar, Venkatachalam; Marcet, Paula L.; Escalante, Ananias A.; Alexander, Neal; Rojas, Carlos

2016-01-01

Plasmodium vivax recurrences help maintain malaria transmission. They are caused by recrudescence, reinfection, or relapse, which are not easily differentiated. A longitudinal observational study took place in Turbo municipality, Colombia. Participants with uncomplicated P. vivax infection received supervised treatment concomitantly with 25 mg/kg chloroquine and 0.25 mg/kg/day primaquine for 14 days. Incidence of recurrence was assessed over 180 days. Samples were genotyped, and origins of recurrences were established. A total of 134 participants were enrolled between February 2012 and July 2013, and 87 were followed for 180 days, during which 29 recurrences were detected. The cumulative incidence of first recurrence was 24.1% (21/87) (95% confidence interval [CI], 14.6 to 33.7%), and 86% (18/21) of these events occurred between days 51 and 110. High genetic diversity of P. vivax strains was found, and 12.5% (16/128) of the infections were polyclonal. Among detected recurrences, 93.1% (27/29) of strains were genotyped as genetically identical to the strain from the previous infection episode, and 65.5% (19/29) of infections were classified as relapses. Our results indicate that there is a high incidence of P. vivax malaria recurrence after treatment in Turbo municipality, Colombia, and that a large majority of these episodes are likely relapses from the previous infection. We attribute this to the primaquine regimen currently used in Colombia, which may be insufficient to eliminate hypnozoites. PMID:27185794

Glucose-6-Phosphate Dehydrogenase Deficiency Genetic Variants in Malaria Patients in Southwestern Ethiopia.

PubMed

Carter, Tamar E; Mekonnen, Seleshi Kebede; Lopez, Karen; Bonnell, Victoria; Damodaran, Lambodhar; Aseffa, Abraham; Janies, Daniel A

2018-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked erythrocyte enzyme disorder with relevance to malaria treatment policy. Treatment with the antimalarial primaquine can result in hemolytic anemia in G6PD-deficient patients. With increased interest in primaquine use, it is important to identify G6PD variants in Ethiopia to inform malaria treatment policy. In the present study, mutations in the G6PD gene are identified in a sample of patients with malaria in Jimma town in southwest Ethiopia. Plasmodium species of infection were confirmed using polymerase chain reaction (PCR) and gel electrophoresis. PCR and Sanger sequencing were performed to observe a portion of the G6PD gene where the common G6PD mutations (A376G, G202A, and C563T) are found. Molecular analysis revealed that most of the samples were single Plasmodium vivax infections (83.7%). For G6PD genotyping, A376G was detected in 23.26% of individuals, whereas G202A and C563T were absent. Three other uncommon mutations were identified: rs782669677 (535G→A), rs370658483, (485 + 37 G→T), and a new mutation at chrX:154535443(C→T). Bioinformatic analysis of these mutations' potential functional impact suggests minimal effect on protein function. The discovery of both common and uncommon G6PD mutations contributes to the discussion on G6PD deficiency and appropriate primaquine treatment in Ethiopia.

Characterization of primaquine imidazolidin-4-ones with antimalarial activity by electrospray ionization-ion trap mass spectrometry

NASA Astrophysics Data System (ADS)

Vale, Nuno; Moreira, Rui; Gomes, Paula

2008-02-01

The extensive characterization by electrospray ionization-ion trap mass spectrometry (ESI-MSn) of 20 imidazolidin-4-ones derived from the antimalarial primaquine was well obtained. These compounds are being under investigation as potential antimalarials, as they have been previously found to be active against rodent P. berghei malaria and to be highly stable under physiological conditions. Experiments by collision-induced dissociation (CID) in the nozzle-skimmer region or by tandem-MS have shown the title compounds to be remarkably stable. Mechanisms are proposed to explain the major fragmentations observed in ESI-MSn experiments. Overall, this work represents an unprecedented contribution to a deeper insight into imidazolidin-4-one antimalarials based on a classic 8-aminoquinolinic scaffold. Data herein reported and discussed may be an useful guide for future studies on therapeutically relevant molecules possessing either the 8-aminoquinoline or the imidazolidin-4-one motifs.

[Association of methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency in malaria patients treated with primaquine].

PubMed

Santana, Marli Stela; da Rocha, Marcos Antonio Ferreira; Arcanjo, Ana Ruth Lima; Sardinha, José Felipe Jardim; Alecrim, Wilson Duarte; Alecrim, Maria das Graças Costa

2007-01-01

This study had the aim of investigating occurrences of methemoglobinemia among individuals with glucose-6-phosphate dehydrogenase deficiency during treatment for malaria infection using primaquine. Patients with a diagnosis of malaria caused by Plasmodium vivax or the V+F mixture (Plasmodium vivax + Plasmodium falciparum) were selected. Group 1 consisted of 74 individuals with a clinical diagnosis of methemoglobinemia and Group 2 consisted of 161 individuals without a clinical diagnosis of methemoglobinemia. The glucose-6-phosphate dehydrogenase deficiency rates (numbers of enzymopenic individuals) in Groups 1 and 2 were 51.3% (38) and 8.7% (14) respectively. These data demonstrated a statistically significant association with methemoglobinemia only among the individuals in Group 1 (p<0.05). Investigation of the relationship between methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency showed that there was a possible association such that enzymopenic individuals may develop methemoglobinemia more frequently.

Safety of 8-aminoquinolines given to people with G6PD deficiency: protocol for systematic review of prospective studies.

PubMed

Uthman, Olalekan A; Saunders, Rachel; Sinclair, David; Graves, Patricia; Gelband, Hellen; Clarke, Aileen; Garner, Paul

2014-05-14

A single dose or short course of primaquine given to people infected with malaria may reduce transmission of Plasmodium falciparum through its effects on gametocytes. Primaquine is also known to cause haemolysis in people with variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency. The objective of this systematic review was to assess the risk of adverse effects in people with G6PD deficiency given primaquine or other 8-aminoquinoline (8AQ) as a single dose or short course (less than 7 days). We will search the following databases: Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and LILACS. Prospective cohort studies, randomised and quasi-randomised trials that evaluated 8AQs for whatever reason in adults or children with a known G6PD deficiency will be included. Two authors will independently assess each study for eligibility, risk of bias and extract data. This systematic review will be published in a peer-reviewed journal. Brief reports of the review findings will be disseminated directly to the appropriate audiences and the WHO Technical Expert Group in Malaria Chemotherapy. As no primary data collection will be undertaken, no additional formal ethical assessment and informed consent are required. The protocol is registered with PROSPERO, registration number CRD42013006518. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Epidemiology and Control of Plasmodium vivax in Afghanistan

PubMed Central

Leslie, Toby; Nahzat, Sami; Sediqi, Walid

2016-01-01

Around half of the population of Afghanistan resides in areas at risk of malaria transmission. Two species of malaria (Plasmodium vivax and Plasmodium falciparum) account for a high burden of disease—in 2011, there were more than 300,000 confirmed cases. Around 80–95% of malaria is P. vivax. Transmission is seasonal and focal, below 2,000 m in altitude, and in irrigated areas which allow breeding of anopheline mosquito vectors. Malaria risk is stratified to improve targeting of interventions. Sixty-three of 400 districts account for ∼85% of cases, and are the target of more intense control efforts. Pressure on the disease is maintained through case management, surveillance, and use of long-lasting insecticide-treated nets. Plasmodium vivax treatment is hampered by the inability to safely treat latent hypnozoites with primaquine because G6PD deficiency affects up to 10% of males in some ethnic groups. The risk of vivax malaria recurrence (which may be as a result of reinfection or relapse) is around 30–45% in groups not treated with primaquine but 3–20% in those given 14-day or 8-week courses of primaquine. Greater access to G6PD testing and radical treatment would reduce the number of incident cases, reduce the infectious reservoir in the population, and has the potential to reduce transmission as a result. Alongside the lack of G6PD testing, under-resourcing and poor security hamper the control of malaria. Recent gains in reducing the burden of disease are fragile and at risk of reversal if pressure on the disease is not maintained. PMID:27708189

Tafenoquine for preventing relapse in people with Plasmodium vivax malaria

PubMed Central

Rajapakse, Senaka; Rodrigo, Chaturaka; Fernando, Sumadhya Deepika

2015-01-01

Background Plasmodium vivax malaria is widespread, and the persistent liver stage causes relapse of the disease which contributes to continued P. vivax transmission. Primaquine is currently the only drug that cures the parasite liver stage, but requires 14 days to be effective and can cause haemolysis in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In addition, there is some evidence of parasite resistance to the drug. Tafenoquine is a new alternative with a longer half-life. Objectives To assess the effects of tafenoquine in people with P. vivax infection. Search methods We searched the following databases up to 13 April 2015: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; CINAHL; SCOPUS; and LILACS. We also searched the World Health Organization (WHO) International Clinical Trial Registry Platform and the metaRegister of Controlled Trials (mRCT) for ongoing trials using "tafenoquine" and "malaria" as search terms up to 13 April 2015. Selection criteria Randomized controlled trials (RCTs) in people with P. vivax malaria. Adverse effects of tafenoquine are assessed in populations where people with G6PD deficiency have been excluded, and in populations without screening for G6PD deficiency. Data collection and analysis All review authors independently extracted data and assessed trial quality. Meta-analysis was carried out where appropriate, and estimates given as relative risk with 95% confidence intervals. We assessed the quality of the evidence using the GRADE approach. Main results Three RCTs met our inclusion criteria, with the asexual infection in both the tafenoquine and comparator arm treated with chloroquine, and in all trials G6PD deficiency patients were excluded. Tafenoquine dose comparisons Three of the included trials compared eight different dosing regimens. Tafenoquine doses of 300 mg and above resulted in fewer relapses than no hypnozoite treatment over six months follow-up in adults (300 mg single dose: RR 0.19, 95% CI 0.08 to 0.41, one trial, 110 participants, moderate quality evidence; 500 to 600 mg single dose: RR 0.14, 95%CI 0.06 to 0.34, two trials, 122 participants, moderate quality evidence; 1800 mg to 3000 mg in divided doses: RR 0.05, 95% CI 0.01 to 0.23, two trials, 63 participants, low quality evidence). In people with normal G6PD status, there may be little or no difference in serious adverse events (three trials, 358 participants, low quality evidence); or any adverse event (one trial, 272 participants, low quality evidence). Tafenoquine versus primaquine Two of the included trials compared four different dosing regimens of tafenoquine against the standard primaquine regimen of 15 mg/day for 14 days. A single tafenoquine dose of 600 mg may be more effective than primaquine in relation to relapses at six months follow-up (RR 0.29, 95% CI 0.10 to 0.84, two trials, 98 participants, low quality evidence) In people with normal G6PD status, there may be little or no difference for serious adverse events (two trials, 323 participants, low quality evidence) or any adverse event (two trials, 323 participants, low quality evidence) between tafenoquine and primaquine. Authors' conclusions Tafenoquine prevents relapses after clinically and parasitologically confirmed P. vivax malaria. The drug is untested in pregnancy, children and in G6PD-deficient people. The shorter treatment course is an important practical advantage in people who do not have G6PD deficiency, but the longer half-life may have more substantive consequences if given inadvertently to people with G6PD deficiency. PLAIN LANGUAGE SUMMARY Tafenoquine for preventing relapse in people with vivax malaria Background Vivax malaria is caused by the parasite Plasmodium vivax. The disease includes a stage of liver infection and this can cause relapse unless treated. The only drug available until recently was primaquine, but this requires a 14-day course of treatment. Alternatives have been tried, one of which is tafenoquine, which does not need such a long course of treatment. Both primaquine and tafenoquine can cause haemolysis in people with glucose-6-phosphate dehydrogenase (G6PD) enzyme deficiency, which is a common genetic defect. We conducted a Cochrane Review on the effect of the drug tafenoquine on clearing the dormant P. vivax parasites in infected patients to prevent a relapse. Review findings Researchers in the Cochrane Collaboration examined the research published up to 13 April 2015. We identified three trials conducted in Thailand, India, Peru and Brazil on adults with confirmedP. vivax malaria that randomized 453 participants. All adults received chloroquine (to clear the parasites in the blood) and some groups received either tafenoquine, primaquine or no further treatment. All were observed for recurrences of P. vivax malaria (up to six months) and all trials tested people for G6PD enzyme, and excluded patients who were deficient. Adults receiving tafenoquine at doses greater than 300 mg had fewer relapses than adults who had no further treatment (moderate quality evidence). Tafenoquine 600 mg may be better in relapse prevention than standard primaquine doses (low quality evidence). In patients who do not have G6PD deficiency, there may be little or no difference in adverse effects (low quality evidence). The drug is untested in children and pregnant women. The shorter treatment course is a practical advantage, but the longer half-life could may have more substantive consequences if given inadvertently to people with G6PD deficiency. PMID:25921416

Tafenoquine plus chloroquine for the treatment and relapse prevention of Plasmodium vivax malaria (DETECTIVE): a multicentre, double-blind, randomised, phase 2b dose-selection study.

PubMed

Llanos-Cuentas, Alejandro; Lacerda, Marcus V; Rueangweerayut, Ronnatrai; Krudsood, Srivicha; Gupta, Sandeep K; Kochar, Sanjay K; Arthur, Preetam; Chuenchom, Nuttagarn; Möhrle, Jörg J; Duparc, Stephan; Ugwuegbulam, Cletus; Kleim, Jörg-Peter; Carter, Nick; Green, Justin A; Kellam, Lynda

2014-03-22

Clinical effectiveness of previous regimens to treat Plasmodium vivax infection have been hampered by compliance. We aimed to assess the dose-response, safety, and tolerability of single-dose tafenoquine plus 3-day chloroquine for P vivax malaria radical cure. In this double-blind, randomised, dose-ranging phase 2b study, men and women (aged ≥16 years) with microscopically confirmed P vivax monoinfection (parasite density >100 to <100,000 per μL blood) were enrolled from community health centres and hospitals across seven sites in Brazil, Peru, India, and Thailand. Patients with glucose-6-phosphate dehydrogenase enzyme activity of less than 70% were excluded. Eligible patients received chloroquine (days 1-3) and were randomly assigned (1:1:1:1:1:1) by a computer-generated randomisation schedule to receive single-dose tafenoquine 50 mg, 100 mg, 300 mg, or 600 mg, primaquine 15 mg for 14 days, or chloroquine alone. Randomisation was stratified by baseline parasite count (≤7500 and >7500 per μL blood). The primary efficacy endpoint was relapse-free efficacy at 6 months from initial dose (ie, clearance of initial infection without subsequent microscopically confirmed infection), analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01376167. Between Sept 19, 2011, and March 25, 2013, 329 patients were randomly assigned to a treatment group (chloroquine plus tafenoquine 50 mg [n=55], 100 mg [n=57], 300 mg [n=57], 600 mg [n=56]; or to chloroquine plus primaquine [n=50]; or chloroquine alone [n=54]). Relapse-free efficacy at 6 months was 57·7% (95% CI 43-70) with tafenoquine 50 mg, 54·1% (40-66) with tafenoquine 100 mg, 89·2% (77-95) with tafenoquine 300 mg, 91·9% (80-97) with tafenoquine 600 mg, 77·3% (63-87) with primaquine, and 37·5% (23-52) with chloroquine alone. Tafenoquine 300 mg and 600 mg had better efficacy than chloroquine alone (treatment differences 51·7% [95% CI 35-69], p<0·0001, with tafenoquine 300 mg and 54·5% [38-71], p<0·0001, with tafenoquine 600 mg), as did primaquine (treatment difference 39·9% [21-59], p=0·0004). Adverse events were similar between treatments. 29 serious adverse events occurred in 26 (8%) of 329 patients; QT prolongation was the most common serious adverse event (11 [3%] of 329), occurring in five (2%) of 225 patients receiving tafenoquine, four (8%) of 50 patients receiving primaquine, and two (4%) of 54 patients receiving chloroquine alone, with no evidence of an additional effect on QT of chloroquine plus tafenoquine coadministration. Single-dose tafenoquine 300 mg coadministered with chloroquine for P vivax malaria relapse prevention was more efficacious than chloroquine alone, with a similar safety profile. As a result, it has been selected for further clinical assessment in phase 3. GlaxoSmithKline, Medicines for Malaria Venture. Copyright © 2014 Elsevier Ltd. All rights reserved.

Safety of Single-Dose Primaquine in G6PD-Deficient and G6PD-Normal Males in Mali Without Malaria: An Open-Label, Phase 1, Dose-Adjustment Trial.

PubMed

Chen, Ingrid; Diawara, Halimatou; Mahamar, Almahamoudou; Sanogo, Koualy; Keita, Sekouba; Kone, Daouda; Diarra, Kalifa; Djimde, Moussa; Keita, Mohamed; Brown, Joelle; Roh, Michelle E; Hwang, Jimee; Pett, Helmi; Murphy, Maxwell; Niemi, Mikko; Greenhouse, Bryan; Bousema, Teun; Gosling, Roly; Dicko, Alassane

2018-03-28

The World Health Organization recommendation on the use of a single low dose of primaquine (SLD-PQ) to reduce Plasmodium falciparum malaria transmission requires more safety data. We conducted an open-label, nonrandomized, dose-adjustment trial of the safety of 3 single doses of primaquine in glucose-6-phosphate dehydrogenase (G6PD)-deficient adult males in Mali, followed by an assessment of safety in G6PD-deficient boys aged 11-17 years and those aged 5-10 years, including G6PD-normal control groups. The primary outcome was the greatest within-person percentage drop in hemoglobin concentration within 10 days after treatment. Fifty-one participants were included in analysis. G6PD-deficient adult males received 0.40, 0.45, or 0.50 mg/kg of SLD-PQ. G6PD-deficient boys received 0.40 mg/kg of SLD-PQ. There was no evidence of symptomatic hemolysis, and adverse events considered related to study drug (n = 4) were mild. The mean largest within-person percentage change in hemoglobin level between days 0 and 10 was -9.7% (95% confidence interval [CI], -13.5% to -5.90%) in G6PD-deficient adults receiving 0.50 mg/kg of SLD-PQ, -11.5% (95% CI, -16.1% to -6.96%) in G6PD-deficient boys aged 11-17 years, and -9.61% (95% CI, -7.59% to -13.9%) in G6PD-deficient boys aged 5-10 years. The lowest hemoglobin concentration at any point during the study was 92 g/L. SLD-PQ doses between 0.40 and 0.50 mg/kg were well tolerated in G6PD-deficient males in Mali. NCT02535767.

Formation of methemoglobin and metmyoglobin using 8-aminoquinoline derivatives or sodium nitrite and subsequent reaction with cyanide.

PubMed

Steinhaus, R K; Baskin, S I; Clark, J H; Kirby, S D

1990-10-01

The kinetics of the oxidation of hemoglobin (Hb) and myoglobin (Mb) by sodium nitrite, 8-[(4-amino-1-methylbutyl)amino]-6-methoxy-quinoline diphosphate (primaquine), 6-methoxy-8-(6-diethylaminohexylamino)-4-methyl-quinoline dihydrochloride (WR6026) and 8-[(4-amino-1-methylbutyl)amino]-2,6-dimethoxy-4-methyl- 5-[(3-trifluoromethyl)phenoxy]quinoline succinate (WR238,605) were studied at pH values ranging from 7.4 to 7.6 and at 37 +/- 1 degrees C. The reaction between Hb and primaquine, WR6026 and WR238,605 resulted in precipitation, as did the reaction between Mb and WR238,605. The reaction between nitrite ion (NO2-) and Hb showed a lag period followed by an autocatalytic phase. The data in this study are consistent with and substantiate the proposed mechanism for the Hb-NO2- oxidation reaction. The reaction between Mb and NO2- at higher NO2- concentrations also showed a lag period followed by an autocatalytic period, while at lower NO2- concentrations no lag period was seen. The data suggest a shift in rate constant at these lower NO2- concentrations. The reaction between Mb and both WR6026 and primaquine followed a two-term rate law with oxidant-dependent and -independent terms. Concentration-effect curve data, along with these results, suggest the presence of a catalytic pathway. The rates of formation of cyanomethemoglobin and cyanometmyoglobin complexes from cyanide ion and methemoglobin (MHb) and metmyoglobin (MMb), respectively, were followed in the presence of the heme oxidants. The rate constants were all within a narrow range and suggest that complexation of cyanide by MHb and MMb is not affected by the presence of oxidants.

Screening for Glucose-6-Phosphate Dehydrogenase Deficiency Using Three Detection Methods: A Cross-Sectional Survey in Southwestern Uganda

PubMed Central

Roh, Michelle E.; Oyet, Caesar; Orikiriza, Patrick; Wade, Martina; Mwanga-Amumpaire, Juliet; Boum, Yap; Kiwanuka, Gertrude N.; Parikh, Sunil

2016-01-01

Despite the potential benefit of primaquine in reducing Plasmodium falciparum transmission and radical cure of Plasmodium vivax and Plasmodium ovale infections, concerns over risk of hemolytic toxicity in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) have hampered its deployment. A cross-sectional survey was conducted in 2014 to assess the G6PDd prevalence among 631 children between 6 and 59 months of age in southwestern Uganda, an area where primaquine may be a promising control measure. G6PDd prevalence was determined using three detection methods: a quantitative G6PD enzyme activity assay (Trinity Biotech® G-6-PDH kit), a qualitative point-of-care test (CareStart™ G6PD rapid diagnostic test [RDT]), and molecular detection of the G6PD A− G202A allele. Qualitative tests were compared with the gold standard quantitative assay. G6PDd prevalence was higher by RDT (8.6%) than by quantitative assay (6.8%), using a < 60% activity threshold. The RDT performed optimally at a < 60% threshold and demonstrated high sensitivity (≥ 90%) and negative predictive values (100%) across three activity thresholds (below 60%, 30%, and 40%). G202A allele frequency was 6.4%, 7.9%, and 6.8% among females, males, and overall, respectively. Notably, over half of the G202A homo-/hemizygous children expressed ≥ 60% enzyme activity. Overall, the CareStart™ G6PD RDT appears to be a viable screening test to accurately identify individuals with enzyme activities below 60%. The low prevalence of G6PDd across all three diagnostic modalities and absence of severe deficiency in our study suggests that there is little barrier to the use of single-dose primaquine in this region. PMID:27672207

Modern malaria chemoprophylaxis.

PubMed

Shanks, G Dennis; Edstein, Michael D

2005-01-01

Currently available medications for malaria chemoprophylaxis are efficacious but the problems of patient compliance, the advance of parasite drug resistance, and real or perceived serious adverse effects mean that new chemical compounds are needed.Primaquine, which has been widely used to treat relapsing malaria since the 1950s, has been shown to prevent malaria when taken daily. Tafenoquine is a new 8-aminoquinoline with a much longer half-life than primaquine. Field trials to date indicate that tafenoquine is efficacious and can be taken weekly or perhaps even less frequently. Both primaquine and tafenoquine require exact knowledge of a person's glucose 6-phosphate dehydrogenase status in order to prevent drug-induced haemolysis. Other potential malaria chemoprophylactic drugs such as third-generation antifol compounds and Mannich bases have reached advanced preclinical testing. Mefloquine has been seen to cause serious neuropsychiatric adverse effects on rare occasions. Recent public controversy regarding reputedly common serious adverse effects has made many Western travellers unwilling to take mefloquine. Special risk groups exposed to malaria, such as long-term travellers, children, pregnant women, aircrew and those requiring unimpeded psychomotor reactions, migrants returning to visit malarious countries of origin and febrile persons who have returned from malaria endemic areas, all require a nuanced approach to the use of drugs to prevent malaria. The carrying of therapeutic courses of antimalarial drugs to be taken only if febrile illness develops is indicated in very few travellers despite its appeal to some who fear adverse effects more than they fear potentially lethal malaria infection. Travellers with a significant exposure to malaria require a comprehensive plan for prevention that includes anti-mosquito measures but which is still primarily be based on the regular use of efficacious antimalarial medications.

Review of key knowledge gaps in glucose-6-phosphate dehydrogenase deficiency detection with regard to the safe clinical deployment of 8-aminoquinoline treatment regimens: a workshop report.

PubMed

von Seidlein, Lorenz; Auburn, Sarah; Espino, Fe; Shanks, Dennis; Cheng, Qin; McCarthy, James; Baird, Kevin; Moyes, Catherine; Howes, Rosalind; Ménard, Didier; Bancone, Germana; Winasti-Satyahraha, Ari; Vestergaard, Lasse S; Green, Justin; Domingo, Gonzalo; Yeung, Shunmay; Price, Ric

2013-03-27

The diagnosis and management of glucose-6-phosphate dehydrogenase (G6PD) deficiency is a crucial aspect in the current phases of malaria control and elimination, which will require the wider use of 8-aminoquinolines for both reducing Plasmodium falciparum transmission and achieving the radical cure of Plasmodium vivax. 8-aminoquinolines, such as primaquine, can induce severe haemolysis in G6PD-deficient individuals, potentially creating significant morbidity and undermining confidence in 8-aminoquinoline prescription. On the other hand, erring on the side of safety and excluding large numbers of people with unconfirmed G6PD deficiency from treatment with 8-aminoquinolines will diminish the impact of these drugs. Estimating the remaining G6PD enzyme activity is the most direct, accessible, and reliable assessment of the phenotype and remains the gold standard for the diagnosis of patients who could be harmed by the administration of primaquine. Genotyping seems an unambiguous technique, but its use is limited by cost and the large range of recognized G6PD genotypes. A number of enzyme activity assays diagnose G6PD deficiency, but they require a cold chain, specialized equipment, and laboratory skills. These assays are impractical for care delivery where most patients with malaria live. Improvements to the diagnosis of G6PD deficiency are required for the broader and safer use of 8-aminoquinolines to kill hypnozoites, while lower doses of primaquine may be safely used to kill gametocytes without testing. The discussions and conclusions of a workshop conducted in Incheon, Korea in May 2012 to review key knowledge gaps in G6PD deficiency are reported here.

Review of key knowledge gaps in glucose-6-phosphate dehydrogenase deficiency detection with regard to the safe clinical deployment of 8-aminoquinoline treatment regimens: a workshop report

PubMed Central

2013-01-01

The diagnosis and management of glucose-6-phosphate dehydrogenase (G6PD) deficiency is a crucial aspect in the current phases of malaria control and elimination, which will require the wider use of 8-aminoquinolines for both reducing Plasmodium falciparum transmission and achieving the radical cure of Plasmodium vivax. 8-aminoquinolines, such as primaquine, can induce severe haemolysis in G6PD-deficient individuals, potentially creating significant morbidity and undermining confidence in 8-aminoquinoline prescription. On the other hand, erring on the side of safety and excluding large numbers of people with unconfirmed G6PD deficiency from treatment with 8-aminoquinolines will diminish the impact of these drugs. Estimating the remaining G6PD enzyme activity is the most direct, accessible, and reliable assessment of the phenotype and remains the gold standard for the diagnosis of patients who could be harmed by the administration of primaquine. Genotyping seems an unambiguous technique, but its use is limited by cost and the large range of recognized G6PD genotypes. A number of enzyme activity assays diagnose G6PD deficiency, but they require a cold chain, specialized equipment, and laboratory skills. These assays are impractical for care delivery where most patients with malaria live. Improvements to the diagnosis of G6PD deficiency are required for the broader and safer use of 8-aminoquinolines to kill hypnozoites, while lower doses of primaquine may be safely used to kill gametocytes without testing. The discussions and conclusions of a workshop conducted in Incheon, Korea in May 2012 to review key knowledge gaps in G6PD deficiency are reported here. PMID:23537118

Blood Stage of Plasmodium vivax in Central China Is Still Susceptible to Chloroquine Plus Primaquine Combination Therapy

PubMed Central

Zhu, Guoding; Lu, Feng; Cao, Jun; Zhou, Huayun; Liu, Yaobao; Han, Eun-Taek; Gao, Qi

2013-01-01

In central China, Plasmodium vivax accounts for all of the native reported cases of malaria. Chloroquine (CQ) plus primaquine (PQ) have been used for more than 60 years as the frontline drugs, but the risk of treatment failure remains unknown. To measure the effectiveness and safety of CQ-PQ among vivax malaria patients, a total of 39 subjects with monoinfection vivax malaria was enrolled in a study from 2008 to 2009. There were no recrudescence or danger signs observed within the 28-day follow-up period, showing that blood stage of P. vivax isolates from central China is still susceptible to CQ plus PQ combination therapy. However, the antirelapse efficacy of PQ is difficult to assess because of the high rate of loss to follow-up after 28 days; also, parasites persisted in a single case at 3 days post-antimalarial drug treatment, indicating that continuous annual monitoring is needed in central China. PMID:23669232

STUDIES ON THE CHEMOTHERAPY OF CHLOROQUINERESISTANT FALCIPARUM MALARIA, VIVAX MALARIA, AND PRIMAQUINE HEMOLYSIS.

DTIC Science & Technology

to chloroquine, hydroxychloroquine , amodiaquin, and 377C54, and is sensitive to pyri methamine and quinine. The three strains from Southeast Asia...are resistant to chloroquine, hydroxychloroquine , amodiaquin, atabrine, chlorguanide, and 377C54; these three strains vary in their response to

Tafenoquine for preventing relapse in people with Plasmodium vivax malaria.

PubMed

Rajapakse, Senaka; Rodrigo, Chaturaka; Fernando, Sumadhya Deepika

2015-04-29

Plasmodium vivax malaria is widespread, and the persistent liver stage causes relapse of the disease which contributes to continued P. vivax transmission. Primaquine is currently the only drug that cures the parasite liver stage, but requires 14 days to be effective and can cause haemolysis in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In addition, there is some evidence of parasite resistance to the drug. Tafenoquine is a new alternative with a longer half-life. To assess the effects of tafenoquine in people with P. vivax infection. We searched the following databases up to 13 April 2015: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; CINAHL; SCOPUS; and LILACS. We also searched the World Health Organization (WHO) International Clinical Trial Registry Platform and the metaRegister of Controlled Trials (mRCT) for ongoing trials using "tafenoquine" and "malaria" as search terms up to 13 April 2015. Randomized controlled trials (RCTs) in people with P. vivax malaria. Adverse effects of tafenoquine are assessed in populations where people with G6PD deficiency have been excluded, and in populations without screening for G6PD deficiency. All review authors independently extracted data and assessed trial quality. Meta-analysis was carried out where appropriate, and estimates given as relative risk with 95% confidence intervals. We assessed the quality of the evidence using the GRADE approach. Three RCTs met our inclusion criteria, with the asexual infection in both the tafenoquine and comparator arm treated with chloroquine, and in all trials G6PD deficiency patients were excluded. Tafenoquine dose comparisonsThree of the included trials compared eight different dosing regimens. Tafenoquine doses of 300 mg and above resulted in fewer relapses than no hypnozoite treatment over six months follow-up in adults (300 mg single dose: RR 0.19, 95% CI 0.08 to 0.41, one trial, 110 participants, moderate quality evidence; 500 to 600 mg single dose: RR 0.14, 95%CI 0.06 to 0.34, two trials, 122 participants, moderate quality evidence; 1800 mg to 3000 mg in divided doses: RR 0.05, 95% CI 0.01 to 0.23, two trials, 63 participants, low quality evidence).In people with normal G6PD status, there may be little or no difference in serious adverse events (three trials, 358 participants, low quality evidence); or any adverse event (one trial, 272 participants, low quality evidence). Tafenoquine versus primaquine Two of the included trials compared four different dosing regimens of tafenoquine against the standard primaquine regimen of 15 mg/day for 14 days. A single tafenoquine dose of 600 mg may be more effective than primaquine in relation to relapses at six months follow-up (RR 0.29, 95% CI 0.10 to 0.84, two trials, 98 participants, low quality evidence)In people with normal G6PD status, there may be little or no difference for serious adverse events (two trials, 323 participants, low quality evidence) or any adverse event (two trials, 323 participants, low quality evidence) between tafenoquine and primaquine. Tafenoquine prevents relapses after clinically and parasitologically confirmed P. vivax malaria. The drug is untested in pregnancy, children and in G6PD-deficient people. The shorter treatment course is an important practical advantage in people who do not have G6PD deficiency, but the longer half-life may have more substantive consequences if given inadvertently to people with G6PD deficiency.

[Congenital hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency].

PubMed

Mura, M; Saidi, R; Wolf, A; Moalic, J L; Oliver, M

2009-12-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common enzyme defect with a wide range of clinical manifestations that can be severe. A variety of factors including many medications can induce hemolytic episodes. Screening for G6PD deficiency is required before use of some drugs especially primaquine or dapsone.

Methemoglobinemia hemotoxicity of some antimalarial 8-aminoquinoline analogues and their hydroxylated derivatives: density functional theory computation of ionization potentials

USDA-ARS?s Scientific Manuscript database

The administration of primaquine (PQ), an essential drug for treatment and radical cure of malaria, can lead to methemoglobin formation and life-threatening hemolysis for glucose-6-phosphate dehydrogenase deficient patients. The ionization potential (IP, a quantitative measure of the ability to lose...

Humanized mouse model of glucose 6-phosphate dehydrogenase deficiency for in vivo assessment of hemolytic toxicity.

PubMed

Rochford, Rosemary; Ohrt, Colin; Baresel, Paul C; Campo, Brice; Sampath, Aruna; Magill, Alan J; Tekwani, Babu L; Walker, Larry A

2013-10-22

Individuals with glucose 6-phosphate dehydrogenase (G6PD) deficiency are at risk for the development of hemolytic anemia when given 8-aminoquinolines (8-AQs), an important class of antimalarial/antiinfective therapeutics. However, there is no suitable animal model that can predict the clinical hemolytic potential of drugs. We developed and validated a human (hu)RBC-SCID mouse model by giving nonobese diabetic/SCID mice daily transfusions of huRBCs from G6PD-deficient donors. Treatment of SCID mice engrafted with G6PD-deficient huRBCs with primaquine, an 8-AQ, resulted in a dose-dependent selective loss of huRBCs. To validate the specificity of this model, we tested known nonhemolytic antimalarial drugs: mefloquine, chloroquine, doxycycline, and pyrimethamine. No significant loss of G6PD-deficient huRBCs was observed. Treatment with drugs known to cause hemolytic toxicity (pamaquine, sitamaquine, tafenoquine, and dapsone) resulted in loss of G6PD-deficient huRBCs comparable to primaquine. This mouse model provides an important tool to test drugs for their potential to cause hemolytic toxicity in G6PD-deficient populations.

Transmission-blocking activity of tafenoquine (WR-238605) and artelinic acid against naturally circulating strains of Plasmodium vivax in Thailand.

PubMed

Ponsa, Narong; Sattabongkot, Jetsumon; Kittayapong, Pattamaporn; Eikarat, Nantana; Coleman, Russell E

2003-11-01

The sporontocidal activity of tafenoquine (WR-238605) and artelinic acid was determined against naturally circulating isolates of Plasmodium vivax in western Thailand. Primaquine was used as a negative control and a dihydroacridine-dione (WR-250547) was used as a positive control. Laboratory-reared Anopheles dirus mosquitoes were infected with P. vivax by allowing mosquitoes to feed on blood (placed in an artificial-membrane feeding apparatus) collected from gametocytemic volunteers reporting to local malaria clinics in Tak province, Thailand. Four days post-infection, mosquitoes were refed on uninfected mice treated 90 minutes earlier with a given drug. Drug activity was determined by assessing oocyst and sporozoite development. Neither primaquine nor artelinic acid affected oocyst or sporozoite development at a dose of 100 mg of base drug/kg of mouse body weight. In contrast, tafenoquine and WR-250547 affected sporogonic development at doses as low as 25.0 and 0.39 mg/kg, respectively. The potential role of these compounds in the prevention of malaria transmission is discussed, as are alternative strategies for the use of transmission-blocking antimalarial drugs.

PKD1/PKCmu promotes alphavbeta3 integrin recycling and delivery to nascent focal adhesions.

PubMed

Woods, Alison J; White, Dominic P; Caswell, Patrick T; Norman, Jim C

2004-07-07

To identify kinases that regulate integrin recycling, we have immunoprecipitated alphavbeta3 integrin from NIH 3T3 fibroblasts in the presence and absence of primaquine (a drug that inhibits receptor recycling and leads to accumulation of integrins in endosomes) and screened for co-precipitating kinases. Primaquine strongly promoted association of alphavbeta3 integrin with PKD1, and fluorescence microscopy indicated that integrin and PKD1 associate at a vesicular compartment that is downstream of a Rab4-dependent transport step. PKD1 association was mediated by the C-terminal region of the beta3 integrin cytodomain, and mutants of beta3 that were unable to recruit PKD1 did not recycle in a PDGF-dependent fashion. Furthermore, suppression of endogenous PKD1 levels by RNAi, or overexpression of catalytically inactive PKD1 inhibited PDGF-dependent recycling of alphavbeta3 from early endosomes to the plasma membrane and blocked recruitment of alphavbeta3 to newly formed focal adhesions during cell spreading. These data indicate that PKD1 influences cell migration by directing vesicular transport of the alphavbeta3 integrin heterodimer.

Glucose-6-phosphate dehydrogenase deficiency and the use of primaquine: top-down and bottom-up estimation of professional costs.

PubMed

Peixoto, Henry Maia; Brito, Marcelo Augusto Mota; Romero, Gustavo Adolfo Sierra; Monteiro, Wuelton Marcelo; Lacerda, Marcus Vinícius Guimarães de; Oliveira, Maria Regina Fernandes de

2017-10-05

The aim of this study has been to study whether the top-down method, based on the average value identified in the Brazilian Hospitalization System (SIH/SUS), is a good estimator of the cost of health professionals per patient, using the bottom-up method for comparison. The study has been developed from the context of hospital care offered to the patient carrier of glucose-6-phosphate dehydrogenase (G6PD) deficiency with severe adverse effect because of the use of primaquine, in the Brazilian Amazon. The top-down method based on the spending with SIH/SUS professional services, as a proxy for this cost, corresponded to R$60.71, and the bottom-up, based on the salaries of the physician (R$30.43), nurse (R$16.33), and nursing technician (R$5.93), estimated a total cost of R$52.68. The difference was only R$8.03, which shows that the amounts paid by the Hospital Inpatient Authorization (AIH) are estimates close to those obtained by the bottom-up technique for the professionals directly involved in the care.

Chloroquine-Primaquine versus Chloroquine Alone to Treat Vivax Malaria in Afghanistan: An Open Randomized Superiority Trial.

PubMed

Awab, Ghulam Rahim; Imwong, Mallika; Bancone, Germana; Jeeyapant, Atthanee; Day, Nicholas P J; White, Nicholas J; Woodrow, Charles J

2017-12-01

Afghanistan's national guidelines recommend primaquine (PQ) for radical treatment of Plasmodium vivax malaria, but this is rarely implemented because of concerns over potential hemolysis in patients who have G6PD deficiency. Between August 2009 and February 2014, we conducted an open-label, randomized controlled trial of chloroquine (CQ) alone versus chloroquine plus primaquine (0.25 mg base/kg/day for 14 days) (CQ+PQ) in patients aged 6 months and older with microscopy confirmed P. vivax infection. In the CQ+PQ group, G6PD deficiency was excluded by fluorescent spot testing. The primary outcome was P. vivax recurrence assessed by survival analysis over one year follow-up. Of 593 patients enrolled, 570 attended at or after 14 days of follow-up. Plasmodium vivax recurrences occurred in 37 (13.1%) of 282 patients in the CQ+PQ arm versus 86 (29.9%) of 288 in the CQ arm (Cox proportional hazard ratio [HR] 0.37, 95% confidence interval [CI] 0.25-0.54) (intention-to-treat analysis). Protection against recurrence was greater in the first 6 months of follow-up (HR 0.082; 95% CI 0.029-0.23) than later (HR 0.65, 95% CI 0.41-1.03). Five of seven patients requiring hospital admission were considered possible cases of PQ-related hemolysis, and PQ was stopped in a further six; however, in none of these cases did hemoglobin fall by ≥ 2 g/dL or to below 7 g/dL, and genotyping did not detect any cases of Mediterranean variant G6PD deficiency. PQ 0.25 mg/kg/day for 14 days prevents relapse of P. vivax in Afghanistan. Patient visits during the first week may improve adherence. Implementation will require deployment of point-of-care phenotypic tests for G6PD deficiency.

Chloroquine–Primaquine versus Chloroquine Alone to Treat Vivax Malaria in Afghanistan: An Open Randomized Superiority Trial

PubMed Central

Awab, Ghulam Rahim; Imwong, Mallika; Bancone, Germana; Jeeyapant, Atthanee; Day, Nicholas P. J.; White, Nicholas J.; Woodrow, Charles J.

2017-01-01

Abstract. Afghanistan’s national guidelines recommend primaquine (PQ) for radical treatment of Plasmodium vivax malaria, but this is rarely implemented because of concerns over potential hemolysis in patients who have G6PD deficiency. Between August 2009 and February 2014, we conducted an open-label, randomized controlled trial of chloroquine (CQ) alone versus chloroquine plus primaquine (0.25 mg base/kg/day for 14 days) (CQ+PQ) in patients aged 6 months and older with microscopy confirmed P. vivax infection. In the CQ+PQ group, G6PD deficiency was excluded by fluorescent spot testing. The primary outcome was P. vivax recurrence assessed by survival analysis over one year follow-up. Of 593 patients enrolled, 570 attended at or after 14 days of follow-up. Plasmodium vivax recurrences occurred in 37 (13.1%) of 282 patients in the CQ+PQ arm versus 86 (29.9%) of 288 in the CQ arm (Cox proportional hazard ratio [HR] 0.37, 95% confidence interval [CI] 0.25–0.54) (intention-to-treat analysis). Protection against recurrence was greater in the first 6 months of follow-up (HR 0.082; 95% CI 0.029–0.23) than later (HR 0.65, 95% CI 0.41–1.03). Five of seven patients requiring hospital admission were considered possible cases of PQ-related hemolysis, and PQ was stopped in a further six; however, in none of these cases did hemoglobin fall by ≥ 2 g/dL or to below 7 g/dL, and genotyping did not detect any cases of Mediterranean variant G6PD deficiency. PQ 0.25 mg/kg/day for 14 days prevents relapse of P. vivax in Afghanistan. Patient visits during the first week may improve adherence. Implementation will require deployment of point-of-care phenotypic tests for G6PD deficiency. PMID:29141719

Population screening for glucose-6-phosphate dehydrogenase deficiencies in Isabel Province, Solomon Islands, using a modified enzyme assay on filter paper dried bloodspots

PubMed Central

2010-01-01

Background Glucose-6-phosphate dehydrogenase deficiency poses a significant impediment to primaquine use for the elimination of liver stage infection with Plasmodium vivax and for gametocyte clearance, because of the risk of life-threatening haemolytic anaemia that can occur in G6PD deficient patients. Although a range of methods for screening G6PD deficiency have been described, almost all require skilled personnel, expensive laboratory equipment, freshly collected blood, and are time consuming; factors that render them unsuitable for mass-screening purposes. Methods A published WST8/1-methoxy PMS method was adapted to assay G6PD activity in a 96-well format using dried blood spots, and used it to undertake population screening within a malaria survey undertaken in Isabel Province, Solomon Islands. The assay results were compared to a biochemical test and a recently marketed rapid diagnostic test. Results Comparative testing with biochemical and rapid diagnostic test indicated that results obtained by filter paper assay were accurate providing that blood spots were assayed within 5 days when stored at ambient temperature and 10 days when stored at 4 degrees. Screening of 8541 people from 41 villages in Isabel Province, Solomon Islands revealed the prevalence of G6PD deficiency as defined by enzyme activity < 30% of normal control was 20.3% and a prevalence of severe deficiency that would predispose to primaquine-induced hemolysis (WHO Class I-II) of 6.9%. Conclusions The assay enabled simple and quick semi-quantitative population screening in a malaria-endemic region. The study indicated a high prevalence of G6PD deficiency in Isabel Province and highlights the critical need to consider G6PD deficiency in the context of P. vivax malaria elimination strategies in Solomon Islands, particularly in light of the potential role of primaquine mass drug administration. PMID:20684792

Population screening for glucose-6-phosphate dehydrogenase deficiencies in Isabel Province, Solomon Islands, using a modified enzyme assay on filter paper dried bloodspots.

PubMed

Kuwahata, Melissa; Wijesinghe, Rushika; Ho, Mei-Fong; Pelecanos, Anita; Bobogare, Albino; Landry, Losi; Bugora, Hugo; Vallely, Andrew; McCarthy, James

2010-08-05

Glucose-6-phosphate dehydrogenase deficiency poses a significant impediment to primaquine use for the elimination of liver stage infection with Plasmodium vivax and for gametocyte clearance, because of the risk of life-threatening haemolytic anaemia that can occur in G6PD deficient patients. Although a range of methods for screening G6PD deficiency have been described, almost all require skilled personnel, expensive laboratory equipment, freshly collected blood, and are time consuming; factors that render them unsuitable for mass-screening purposes. A published WST8/1-methoxy PMS method was adapted to assay G6PD activity in a 96-well format using dried blood spots, and used it to undertake population screening within a malaria survey undertaken in Isabel Province, Solomon Islands. The assay results were compared to a biochemical test and a recently marketed rapid diagnostic test. Comparative testing with biochemical and rapid diagnostic test indicated that results obtained by filter paper assay were accurate providing that blood spots were assayed within 5 days when stored at ambient temperature and 10 days when stored at 4 degrees. Screening of 8541 people from 41 villages in Isabel Province, Solomon Islands revealed the prevalence of G6PD deficiency as defined by enzyme activity < 30% of normal control was 20.3% and a prevalence of severe deficiency that would predispose to primaquine-induced hemolysis (WHO Class I-II) of 6.9%. The assay enabled simple and quick semi-quantitative population screening in a malaria-endemic region. The study indicated a high prevalence of G6PD deficiency in Isabel Province and highlights the critical need to consider G6PD deficiency in the context of P. vivax malaria elimination strategies in Solomon Islands, particularly in light of the potential role of primaquine mass drug administration.

Systematic review of the clinical manifestations of glucose-6-phosphate dehydrogenase deficiency in the Greater Mekong Subregion: implications for malaria elimination and beyond.

PubMed

Ong, Ken Ing Cherng; Kosugi, Hodaka; Thoeun, Sophea; Araki, Hitomi; Thandar, Moe Moe; Iwagami, Moritoshi; Hongvanthong, Bouasy; Brey, Paul T; Kano, Shigeyuki; Jimba, Masamine

2017-01-01

To achieve malaria elimination in the Greater Mekong Subregion (GMS) by 2030, proper case management is necessary. 8-aminoquinolines, such as primaquine, are the only available medicines effective in preventing relapse of the hypnozoite stage of Plasmodium vivax , as well as the onward transmission of Plasmodium falciparum . However, primaquine can cause haemolysis in individuals who have glucose-6-phosphate dehydrogenase deficiency (G6PDd). We conducted a systematic review on the reported clinical manifestations of G6PDd to provide a comprehensive overview of the situation in the GMS. The protocol for this systematic review was registered on PROSPERO: International prospective register of systematic reviews (CRD42016043146). We searched the PubMed/MEDLINE, CINAHL, and Web of Science databases for published articles describing the clinical manifestations of G6PDd in the GMS. We included articles of all study designs from inception until 31 July 2016, reporting the clinical manifestations of G6PDd. We then performed a narrative synthesis of these articles. We included 56 articles in this review, 45 of which were from Thailand. Haemolysis in G6PD-deficient individuals was caused not only by primaquine but also by other medicines and infections. Other clinical manifestations of G6PDd that were found were favism, neonatal jaundice and chronic non-spherocytic haemolytic anaemia. G6PDd also influenced the clinical presentations of genetic disorders and infections, such as thalassemia and typhoid fever. As G6PDd also affects the clinical presentations of other infections, the benefits of G6PD testing and proper record keeping transcend those of malaria case management. Therefore, healthcare workers at the community level should be made familiar with complications resulting from G6PDd as these complications extend beyond the scope of malaria.

Noninferiority of glucose-6-phosphate dehydrogenase deficiency diagnosis by a point-of-care rapid test vs the laboratory fluorescent spot test demonstrated by copper inhibition in normal human red blood cells.

PubMed

Baird, J Kevin; Dewi, Mewahyu; Subekti, Decy; Elyazar, Iqbal; Satyagraha, Ari W

2015-06-01

Tens of millions of patients diagnosed with vivax malaria cannot safely receive primaquine therapy against repeated attacks caused by activation of dormant liver stages called hypnozoites. Most of these patients lack access to screening for glucose-6-phosphate dehydrogenase (G6PD) deficiency, a highly prevalent disorder causing serious acute hemolytic anemia with primaquine therapy. We optimized CuCl inhibition of G6PD in normal red blood cells (RBCs) to assess G6PD diagnostic technologies suited to point of care in the impoverished rural tropics. The most widely applied technology for G6PD screening-the fluorescent spot test (FST)-is impractical in that setting. We evaluated a new point-of-care G6PD screening kit (CareStart G6PD, CSG) against FST using graded CuCl treatments to simulate variable hemizygous states, and varying proportions of CuCl-treated RBC suspensions to simulate variable heterozygous states of G6PD deficiency. In experiments double-blinded to CuCl treatment, technicians reading FST and CSG test (n = 269) classified results as positive or negative for deficiency. At G6PD activity ≤40% of normal (n = 112), CSG test was not inferior to FST in detecting G6PD deficiency (P = 0.003), with 96% vs 90% (P = 0.19) sensitivity and 75% and 87% (P = 0.01) specificity, respectively. The CSG test costs less, requires no specialized equipment, laboratory skills, or cold chain for successful application, and performs as well as the FST standard of care for G6PD screening. Such a device may vastly expand access to primaquine therapy and aid in mitigating the very substantial burden of morbidity and mortality imposed by the hypnozoite reservoir of vivax malaria. Copyright © 2015 Elsevier Inc. All rights reserved.

Systematic review of the clinical manifestations of glucose-6-phosphate dehydrogenase deficiency in the Greater Mekong Subregion: implications for malaria elimination and beyond

PubMed Central

Ong, Ken Ing Cherng; Kosugi, Hodaka; Thoeun, Sophea; Araki, Hitomi; Thandar, Moe Moe; Iwagami, Moritoshi; Hongvanthong, Bouasy; Brey, Paul T; Kano, Shigeyuki; Jimba, Masamine

2017-01-01

Introduction To achieve malaria elimination in the Greater Mekong Subregion (GMS) by 2030, proper case management is necessary. 8-aminoquinolines, such as primaquine, are the only available medicines effective in preventing relapse of the hypnozoite stage of Plasmodium vivax, as well as the onward transmission of Plasmodium falciparum. However, primaquine can cause haemolysis in individuals who have glucose-6-phosphate dehydrogenase deficiency (G6PDd). We conducted a systematic review on the reported clinical manifestations of G6PDd to provide a comprehensive overview of the situation in the GMS. Methods The protocol for this systematic review was registered on PROSPERO: International prospective register of systematic reviews (CRD42016043146). We searched the PubMed/MEDLINE, CINAHL, and Web of Science databases for published articles describing the clinical manifestations of G6PDd in the GMS. We included articles of all study designs from inception until 31 July 2016, reporting the clinical manifestations of G6PDd. We then performed a narrative synthesis of these articles. Results We included 56 articles in this review, 45 of which were from Thailand. Haemolysis in G6PD-deficient individuals was caused not only by primaquine but also by other medicines and infections. Other clinical manifestations of G6PDd that were found were favism, neonatal jaundice and chronic non-spherocytic haemolytic anaemia. G6PDd also influenced the clinical presentations of genetic disorders and infections, such as thalassemia and typhoid fever. Conclusion As G6PDd also affects the clinical presentations of other infections, the benefits of G6PD testing and proper record keeping transcend those of malaria case management. Therefore, healthcare workers at the community level should be made familiar with complications resulting from G6PDd as these complications extend beyond the scope of malaria. PMID:29082022

Screening for Glucose-6-Phosphate Dehydrogenase Deficiency Using Three Detection Methods: A Cross-Sectional Survey in Southwestern Uganda.

PubMed

Roh, Michelle E; Oyet, Caesar; Orikiriza, Patrick; Wade, Martina; Mwanga-Amumpaire, Juliet; Boum, Yap; Kiwanuka, Gertrude N; Parikh, Sunil

2016-11-02

Despite the potential benefit of primaquine in reducing Plasmodium falciparum transmission and radical cure of Plasmodium vivax and Plasmodium ovale infections, concerns over risk of hemolytic toxicity in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) have hampered its deployment. A cross-sectional survey was conducted in 2014 to assess the G6PDd prevalence among 631 children between 6 and 59 months of age in southwestern Uganda, an area where primaquine may be a promising control measure. G6PDd prevalence was determined using three detection methods: a quantitative G6PD enzyme activity assay (Trinity Biotech ® G-6-PDH kit), a qualitative point-of-care test (CareStart ™ G6PD rapid diagnostic test [RDT]), and molecular detection of the G6PD A- G202A allele. Qualitative tests were compared with the gold standard quantitative assay. G6PDd prevalence was higher by RDT (8.6%) than by quantitative assay (6.8%), using a < 60% activity threshold. The RDT performed optimally at a < 60% threshold and demonstrated high sensitivity (≥ 90%) and negative predictive values (100%) across three activity thresholds (below 60%, 30%, and 40%). G202A allele frequency was 6.4%, 7.9%, and 6.8% among females, males, and overall, respectively. Notably, over half of the G202A homo-/hemizygous children expressed ≥ 60% enzyme activity. Overall, the CareStart ™ G6PD RDT appears to be a viable screening test to accurately identify individuals with enzyme activities below 60%. The low prevalence of G6PDd across all three diagnostic modalities and absence of severe deficiency in our study suggests that there is little barrier to the use of single-dose primaquine in this region. © The American Society of Tropical Medicine and Hygiene.

Drug Evaluation in the Plasmodium Falciparum - Aotus Model

DTIC Science & Technology

1994-03-15

falciparum infections. Althogh erythromycin is inactive against chloroquine -resistant falciparum infections, an analogue , azithromycin, is effective in vitro...response to chloroquine , and then expand the evaluation of WR 238605, a primaquine analogue against infections. Each cyopreserved sample was thawed rapidly...confirmedo.4 chloroquine -sensitive p. via -strai-n[as not Infective for unaltered Panamanian Aotus. 14. SUBJECT TERMS 15. NUMBER OF PAGES Malaria

Reemergence of Plasmodium vivax malaria in the republic of Korea.

PubMed Central

Feighner, B. H.; Pak, S. I.; Novakoski, W. L.; Kelsey, L. L.; Strickman, D.

1998-01-01

Plasmodium vivax malaria reemerged in the Republic of Korea in 1993. The number of cases has tripled each year since, with more than 1,600 cases reported in 1997. All 27 cases in U.S. troops resolved uneventfully with chloroquine/primaquine therapy. Disease is localized along the western Demilitarized Zone and presents minimal risk to tourists. PMID:9621202

A new procedure for N1-alkylation of imidazolidin-4-ones and its NMR characterization

NASA Astrophysics Data System (ADS)

Vale, Nuno; Figueiredo, Patrícia

2016-12-01

N1-unsubstituted imidazolidin-4-ones of primaquine (PQ) can be stabilized by N1-alkylation under basic conditions. Here we report the development, with our conditions, of peptidomimetic derivatives of PQ with L-amino acid and alkyl derivatives. The new derivatives represent potential new therapeutics for use against protozoan parasites, through enzymatic protection of aminopeptidases.

In Vitro Activities of Primaquine-Schizonticide Combinations on Asexual Blood Stages and Gametocytes of Plasmodium falciparum

PubMed Central

Cabrera, Mynthia

2015-01-01

Currently, the World Health Organization recommends addition of a 0.25-mg base/kg single dose of primaquine (PQ) to artemisinin combination therapies (ACTs) for Plasmodium falciparum malaria as a gametocytocidal agent for reducing transmission. Here, we investigated the potential interactions of PQ with the long-lasting components of the ACT drugs for eliminating the asexual blood stages and gametocytes of in vitro-cultured P. falciparum strains. Using the SYBR green I assay for asexual parasites and a flow cytometry-based assay for gametocytes, we determined the interactions of PQ with the schizonticides chloroquine, mefloquine, piperaquine, lumefantrine, and naphthoquine. With the sums of fractional inhibitory concentrations and isobolograms, we were able to determine mostly synergistic interactions for the various PQ and schizonticide combinations on the blood stages of P. falciparum laboratory strains. The synergism in inhibiting asexual stages and gametocytes was highly evident with PQ-naphthoquine, whereas synergism was moderate for the PQ-piperaquine, PQ-chloroquine, and PQ-mefloquine combinations. We have detected potentially antagonistic interactions between PQ and lumefantrine under certain drug combination ratios, suggesting that precautions might be needed when PQ is added as the gametocytocide to the artemether-lumefantrine ACT (Coartem). PMID:26416869

Point-of-care G6PD diagnostics for Plasmodium vivax malaria is a clinical and public health urgency.

PubMed

Baird, J Kevin

2015-12-14

Malaria caused by Plasmodium vivax threatens over 2 billion people globally and sickens tens of millions annually. Recent clinical evidence discredits the long-held notion of this infection as intrinsically benign revealing an often threatening course associated with mortality. Most acute attacks by this species derive from latent forms in the human liver called hypnozoites. Radical cure for P. vivax malaria includes therapy aimed both at the acute attack (blood schizontocidal) and against future attacks (hypnozoitocidal). The only hypnozoitocide available is primaquine, a drug causing life-threatening acute hemolytic anemia in patients with the inherited blood disorder glucose-6-phosphate dehydrogenase (G6PD) deficiency. This disorder affects 400 million people worldwide, at an average prevalence of 8 % in malaria-endemic nations. In the absence of certain knowledge regarding the G6PD status of patients infected by P. vivax, providers must choose between the risk of harm caused by primaquine and that caused by the parasite by withholding therapy. Resolving this dilemma requires the availability of point-of-care G6PD diagnostics practical for use in the impoverished rural tropics where the vast majority of malaria patients seek care.

Humanized mouse model of glucose 6-phosphate dehydrogenase deficiency for in vivo assessment of hemolytic toxicity

PubMed Central

Rochford, Rosemary; Ohrt, Colin; Baresel, Paul C.; Campo, Brice; Sampath, Aruna; Magill, Alan J.; Tekwani, Babu L.; Walker, Larry A.

2013-01-01

Individuals with glucose 6-phosphate dehydrogenase (G6PD) deficiency are at risk for the development of hemolytic anemia when given 8-aminoquinolines (8-AQs), an important class of antimalarial/antiinfective therapeutics. However, there is no suitable animal model that can predict the clinical hemolytic potential of drugs. We developed and validated a human (hu)RBC-SCID mouse model by giving nonobese diabetic/SCID mice daily transfusions of huRBCs from G6PD-deficient donors. Treatment of SCID mice engrafted with G6PD-deficient huRBCs with primaquine, an 8-AQ, resulted in a dose-dependent selective loss of huRBCs. To validate the specificity of this model, we tested known nonhemolytic antimalarial drugs: mefloquine, chloroquine, doxycycline, and pyrimethamine. No significant loss of G6PD-deficient huRBCs was observed. Treatment with drugs known to cause hemolytic toxicity (pamaquine, sitamaquine, tafenoquine, and dapsone) resulted in loss of G6PD-deficient huRBCs comparable to primaquine. This mouse model provides an important tool to test drugs for their potential to cause hemolytic toxicity in G6PD-deficient populations. PMID:24101478

Prevention of Malaria Resurgence in Greece through the Association of Mass Drug Administration (MDA) to Immigrants from Malaria-Endemic Regions and Standard Control Measures.

PubMed

Tseroni, Maria; Baka, Agoritsa; Kapizioni, Christina; Snounou, Georges; Tsiodras, Sotirios; Charvalakou, Maria; Georgitsou, Maria; Panoutsakou, Maria; Psinaki, Ioanna; Tsoromokou, Maria; Karakitsos, George; Pervanidou, Danai; Vakali, Annita; Mouchtouri, Varvara; Georgakopoulou, Theano; Mamuris, Zissis; Papadopoulos, Nikos; Koliopoulos, George; Badieritakis, Evangelos; Diamantopoulos, Vasilis; Tsakris, Athanasios; Kremastinou, Jenny; Hadjichristodoulou, Christos

2015-11-01

Greece was declared malaria-free in 1974 after a long antimalarial fight. In 2011-2012, an outbreak of P. vivax malaria was reported in Evrotas, an agricultural area in Southern Greece, where a large number of immigrants from endemic countries live and work. A total of 46 locally acquired and 38 imported malaria cases were detected. Despite a significant decrease of the number of malaria cases in 2012, a mass drug administration (MDA) program was considered as an additional measure to prevent reestablishment of the disease in the area. During 2013 and 2014, a combination of 3-day chloroquine and 14-day primaquine treatment was administered under direct observation to immigrants living in the epicenter of the 2011 outbreak in Evrotas. Adverse events were managed and recorded on a daily basis. The control measures implemented since 2011 continued during the period of 2013-2014 as a part of a national integrated malaria control program that included active case detection (ACD), vector control measures and community education. The MDA program was started prior to the transmission periods (from May to December). One thousand ninety four (1094) immigrants successfully completed the treatment, corresponding to 87.3% coverage of the target population. A total of 688 adverse events were recorded in 397 (36.2%, 95% C.I.: 33.4-39.1) persons, the vast majority minor, predominantly dizziness and headache for chloroquine (284 events) and abdominal pain (85 events) for primaquine. A single case of primaquine-induced hemolysis was recorded in a person whose initial G6PD test proved incorrect. No malaria cases were recorded in Evrotas, Laconia, in 2013 and 2014, though three locally acquired malaria cases were recorded in other regions of Greece in 2013. Preventive antimalarial MDA to a high-risk population in a low transmission setting appears to have synergized with the usual antimalarial activities to achieve malaria elimination. This study suggests that judicious use of MDA can be a useful addition to the antimalarial armamentarium in areas threatened with the reintroduction of the disease.

Prevention of Malaria Resurgence in Greece through the Association of Mass Drug Administration (MDA) to Immigrants from Malaria-Endemic Regions and Standard Control Measures

PubMed Central

Tseroni, Maria; Baka, Agoritsa; Kapizioni, Christina; Snounou, Georges; Tsiodras, Sotirios; Charvalakou, Maria; Georgitsou, Maria; Panoutsakou, Maria; Psinaki, Ioanna; Tsoromokou, Maria; Karakitsos, George; Pervanidou, Danai; Vakali, Annita; Mouchtouri, Varvara; Georgakopoulou, Theano; Mamuris, Zissis; Papadopoulos, Nikos; Koliopoulos, George; Badieritakis, Evangelos; Diamantopoulos, Vasilis; Tsakris, Athanasios; Kremastinou, Jenny; Hadjichristodoulou, Christos

2015-01-01

Greece was declared malaria-free in 1974 after a long antimalarial fight. In 2011–2012, an outbreak of P. vivax malaria was reported in Evrotas, an agricultural area in Southern Greece, where a large number of immigrants from endemic countries live and work. A total of 46 locally acquired and 38 imported malaria cases were detected. Despite a significant decrease of the number of malaria cases in 2012, a mass drug administration (MDA) program was considered as an additional measure to prevent reestablishment of the disease in the area. During 2013 and 2014, a combination of 3-day chloroquine and 14-day primaquine treatment was administered under direct observation to immigrants living in the epicenter of the 2011 outbreak in Evrotas. Adverse events were managed and recorded on a daily basis. The control measures implemented since 2011 continued during the period of 2013–2014 as a part of a national integrated malaria control program that included active case detection (ACD), vector control measures and community education. The MDA program was started prior to the transmission periods (from May to December). One thousand ninety four (1094) immigrants successfully completed the treatment, corresponding to 87.3% coverage of the target population. A total of 688 adverse events were recorded in 397 (36.2%, 95% C.I.: 33.4–39.1) persons, the vast majority minor, predominantly dizziness and headache for chloroquine (284 events) and abdominal pain (85 events) for primaquine. A single case of primaquine-induced hemolysis was recorded in a person whose initial G6PD test proved incorrect. No malaria cases were recorded in Evrotas, Laconia, in 2013 and 2014, though three locally acquired malaria cases were recorded in other regions of Greece in 2013. Preventive antimalarial MDA to a high-risk population in a low transmission setting appears to have synergized with the usual antimalarial activities to achieve malaria elimination. This study suggests that judicious use of MDA can be a useful addition to the antimalarial armamentarium in areas threatened with the reintroduction of the disease. PMID:26583650

Reemergence, Persistence, and Surveillance of Vivax Malaria and Its Vectors in the Republic of Korea

DTIC Science & Technology

2008-01-01

chemoprophylaxis policy in 1997,.placing approximately 16,000 soldiers on hydroxychloroquine sulfate (400 mg) and terminal primaquine prophylaxis (Figure n...As malaria increased. more soldiers were placed on chemoprophylaxis and by 2000; approximately 90.000 soldiers were placed on hydroxychloroquine ...it is unknown whether these breakthroughs are due to non-compliance, hydroxychloroquine failure, or both. From 1993 through 2007 there were a total

The metabolism of primaquine to its active metabolite is dependent on CYP 2D6.

PubMed

Pybus, Brandon S; Marcsisin, Sean R; Jin, Xiannu; Deye, Gregory; Sousa, Jason C; Li, Qigui; Caridha, Diana; Zeng, Qiang; Reichard, Gregory A; Ockenhouse, Christian; Bennett, Jason; Walker, Larry A; Ohrt, Colin; Melendez, Victor

2013-06-20

The efficacy of the 8-aminoquinoline (8AQ) drug primaquine (PQ) has been historically linked to CYP-mediated metabolism. Although to date no clear evidence exists in the literature that unambiguously assigns the metabolic pathway or specific metabolites necessary for activity, recent literature suggests a role for CYP 2D6 in the generation of redox active metabolites. In the present study, the specific CYP 2D6 inhibitor paroxetine was used to assess its effects on the production of specific phenolic metabolites thought to be involved in PQ efficacy. Further, PQ causal prophylactic (developing liver stage) efficacy against Plasmodium berghei in CYP 2D knockout mice was assessed in comparison with a normal C57 background and with humanized CYP 2D6 mice to determine the direct effects of CYP 2D6 metabolism on PQ activity. PQ exhibited no activity at 20 or 40 mg/kg in CYP 2D knockout mice, compared to 5/5 cures in normal mice at 20 mg/kg. The activity against developing liver stages was partially restored in humanized CYP 2D6 mice. These results unambiguously demonstrate that metabolism of PQ by CYP 2D6 is essential for anti-malarial causal prophylaxis efficacy.

In Vitro Activities of Primaquine-Schizonticide Combinations on Asexual Blood Stages and Gametocytes of Plasmodium falciparum.

PubMed

Cabrera, Mynthia; Cui, Liwang

2015-12-01

Currently, the World Health Organization recommends addition of a 0.25-mg base/kg single dose of primaquine (PQ) to artemisinin combination therapies (ACTs) for Plasmodium falciparum malaria as a gametocytocidal agent for reducing transmission. Here, we investigated the potential interactions of PQ with the long-lasting components of the ACT drugs for eliminating the asexual blood stages and gametocytes of in vitro-cultured P. falciparum strains. Using the SYBR green I assay for asexual parasites and a flow cytometry-based assay for gametocytes, we determined the interactions of PQ with the schizonticides chloroquine, mefloquine, piperaquine, lumefantrine, and naphthoquine. With the sums of fractional inhibitory concentrations and isobolograms, we were able to determine mostly synergistic interactions for the various PQ and schizonticide combinations on the blood stages of P. falciparum laboratory strains. The synergism in inhibiting asexual stages and gametocytes was highly evident with PQ-naphthoquine, whereas synergism was moderate for the PQ-piperaquine, PQ-chloroquine, and PQ-mefloquine combinations. We have detected potentially antagonistic interactions between PQ and lumefantrine under certain drug combination ratios, suggesting that precautions might be needed when PQ is added as the gametocytocide to the artemether-lumefantrine ACT (Coartem). Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Efficacy of three different regimens of primaquine for the prevention of relapses of Plasmodium vivax malaria in the Amazon Basin of Peru.

PubMed

Durand, Salomón; Cabezas, Cesar; Lescano, Andres G; Galvez, Mariela; Gutierrez, Sonia; Arrospide, Nancy; Alvarez, Carlos; Santolalla, Meddly L; Bacon, David J; Graf, Paul C F

2014-07-01

We evaluated the efficacy of three primaquine (PQ) regimes to prevent relapses with Plasmodium vivax through an open-label randomized trial in Loreto, Peru. Vivax monoinfections were treated with chloroquine for 3 days and PQ in three different regimes: 0.5 mg/kg per day for 5 days (150 mg total), 0.5 mg/kg per day for 7 days (210 mg total), or 0.25 mg/kg per day for 14 days (210 mg total). Biweekly fever assessments and bimonthly thick smears were taken for 210 days. Recurrences after 35 days were considered relapses. One hundred eighty cases were enrolled in each group; 90% of cases completed follow-up. There were no group-related differences in age, sex, or parasitemia. Relapse rates were similar in the 7- and 14-day regimes (16/156 = 10.3% and 22/162 = 13.6%, P = 0.361) and higher in the 5-day group (48/169 = 28.4%, P < 0.001 and P = 0.001, respectively). The 7-day PQ regimen used in Peru is as efficacious as the recommended 14-day regimen and superior to 5 treatment days. © The American Society of Tropical Medicine and Hygiene.

Cytoplasmic remodeling of erythrocyte raft lipids during infection by the human malaria parasite Plasmodium falciparum

PubMed Central

Murphy, Sean C.; Fernandez-Pol, Sebastian; Chung, Paul H.; Prasanna Murthy, S. N.; Milne, Stephen B.; Salomao, Marcela; Brown, H. Alex; Lomasney, Jon W.; Mohandas, Narla

2007-01-01

Studies of detergent-resistant membrane (DRM) rafts in mature erythrocytes have facilitated identification of proteins that regulate formation of endovacuolar structures such as the parasitophorous vacuolar membrane (PVM) induced by the malaria parasite Plasmodium falciparum. However, analyses of raft lipids have remained elusive because detergents interfere with lipid detection. Here, we use primaquine to perturb the erythrocyte membrane and induce detergent-free buoyant vesicles, which are enriched in cholesterol and major raft proteins flotillin and stomatin and contain low levels of cytoskeleton, all characteristics of raft microdomains. Lipid mass spectrometry revealed that phosphatidylethanolamine and phosphatidylglycerol are depleted in endovesicles while phosphoinositides are highly enriched, suggesting raft-based endovesiculation can be achieved by simple (non–receptor-mediated) mechanical perturbation of the erythrocyte plasma membrane and results in sorting of inner leaflet phospholipids. Live-cell imaging of lipid-specific protein probes showed that phosphatidylinositol (4,5) bisphosphate (PIP2) is highly concentrated in primaquine-induced vesicles, confirming that it is an erythrocyte raft lipid. However, the malarial PVM lacks PIP2, although another raft lipid, phosphatidylserine, is readily detected. Thus, different remodeling/sorting of cytoplasmic raft phospholipids may occur in distinct endovacuoles. Importantly, erythrocyte raft lipids recruited to the invasion junction by mechanical stimulation may be remodeled by the malaria parasite to establish blood-stage infection. PMID:17526861

Malaria notifications in the Australian Defence Force from 1998 to 2007.

PubMed

Elmes, Nathan J

2010-06-01

We report here a retrospective analysis of all malaria cases in military personnel reported to the Australian Defence Force (ADF) Central Malaria Register from 1998 to 2007. A total of 637 cases of malaria were notified affecting 487 individuals. Of these 85.9% (547) were infected with Plasmodium vivax malaria and 10.2% (65) with P. falciparum malaria. The majority of cases were from Timor Leste (78.5%, 501/637). Malaria attack rates of 0.9% (369/40 571), 1.1% (52/4776) and 0.4% (20/5345) were seen in Timor Leste, Bougainville and the Solomon Islands, respectively. The median period following departure from a malarious country to presentation of P. falciparum was 17 d (range 1-47 d) and for a primary presentation of P. vivax malaria was 86 d (range 1-505 d). Increasing the dose of primaquine from 22.5 mg daily to 30 mg daily for 14 d for radical cure of P. vivax malaria reduced the failure rate from 46.6% (35/75) to 9.4% (17/181) in subjects returning from Timor Leste. Malaria remains a serious problem for ADF soldiers deploying to malarious areas, particularly the incidence of relapsing vivax malaria and the tolerance of these vivax strains to primaquine.

Side Effects of Chloroquine and Primaquine and Symptom Reduction in Malaria Endemic Area (Mâncio Lima, Acre, Brazil)

PubMed Central

Braga, Cássio Braga e; Martins, Antonio Camargo; Cayotopa, Athaid David Escalante; Klein, Wagner Werner; Schlosser, Andreus Roberto; da Silva, Aline Ferreira; de Souza, Mardelson Nery; Andrade, Breno Wilson Benevides; Filgueira-Júnior, José Alcântara; Pinto, Wagner de Jesus; da Silva-Nunes, Mônica

2015-01-01

Side effects of antimalarial drug can overlap with malaria symptoms. We evaluated 50 patients with vivax malaria in Mâncio Lima, Acre, treated with chloroquine and primaquine. Patients were evaluated for the presence of 21 symptoms before and after treatment and for reported side effects of these drugs after treatment was started. The most frequent symptoms before medication were headache, fever, chills, sweating, arthralgia, back pain, and weakness, which were present in between 40% and 76% of respondents. The treatment reduced the occurrence of these symptoms and reduced the lack of appetite, but gastrointestinal symptoms and choluria increased in frequency. There were no reports of pale stools before medication, but 12% reported the occurrence of this symptom after treatment started. Other symptoms such as blurred vision (54%), pruritus (22%), paresthesia (6%), insomnia (46%), and “stings” into the skin (22%) were reported after chloroquine was taken. The antimalarial drugs used to treat P. vivax malaria reduce much of the systemic and algic symptoms but cause mainly gastrointestinal side effects that may lead to lack of adherence to drug treatment. It is important to guide the patient for the appearance and the transience of such side effects in order to avoid abandoning treatment. PMID:26357512

Medical Surveillance Monthly Report (MSMR). Volume 11, Number 4, July/August 2005

DTIC Science & Technology

2005-08-01

infections with P. vivax and P. ovale.2 However, primaquine can cause hemolytic anemia in individuals with glucose - 6 - phosphate dehydrogenase (G6PD...1):45-52. 4. Farmer KL. Memorandum for commanders and MEDCOM major subordinate commands, subject: Army glucose 6 -phospate dehydrogenase deficiency ...Table 6 . HIV-1 tests, by indication, US Army, 2004 MSMR 9Vol. 11/No. 4 Case reports: Malaria in U.S. Soldiers after Returning from

Therapeutic efficacy of chloroquine and chloroquine plus primaquine for the treatment of Plasmodium vivax in Ethiopia.

PubMed

Yeshiwondim, Asnakew K; Tekle, Afework H; Dengela, Dereje O; Yohannes, Ambachew M; Teklehaimanot, Awash

2010-02-01

Plasmodium vivax is the second most important cause of morbidity in Ethiopia. There is, however, little information on P. vivax resistance to chloroquine and chloroquine plus primaquine treatment although these drugs have been used as the first line treatment for over 50 years. We assessed the efficacy of standard chloroquine and chloroquine plus primaquine treatment for P. vivax infections in a randomized open-label comparative study in Debre Zeit and Nazareth in East Shoa, Ethiopia. A total of 290 patients with microscopically confirmed P. vivax malaria who presented to the outpatient settings of the two laboratory centers were enrolled: 145 patients were randomized to receive CQ and 145 to receive CQ+PQ treatment. Participants were followed-up for 28-157 days according to the WHO procedures. There were 12 (6.5%) lost to follow-up patients and 9 (3.1%) withdrawals. In all, 96% (277/290) of patients were analysed at day 28. Baseline characteristics were similar in all treatment groups. In all, 98.6% (275/277) of patients had cleared their parasitemia on day 3 with no difference in mean parasite clearance time between regimens (48.34+/-17.68, 50.67+/-15.70 h for the CQ and CQ+PQ group, respectively, P=0.25). The cumulative incidence of therapeutic failure at day 28 by a life-table analysis method was 5.76% (95% CI: 2.2-14.61) and 0.75% (95% CI: 0.11-5.2%) in the CQ and CQ+PQ group, respectively (P=0.19). The relapse rate was 8% (9/108) for the CQ group and 3% (4/132) for the comparison group (P=0.07). The cumulative risk of relapse at day 157 by a life-table method was 61.8% (95% CI: 20.1-98.4%) in the CQ group, compared with 26.3% (95% CI: 7.5-29.4%) in the CQ+PQ group (P=0.0038). The study confirms the emergence of CQ and PQ resistance/treatment failure in P. vivax malaria in Ethiopia. Although treatment failures were detected, they were similar between the treatment groups. We recommend regular monitoring and periodic evaluation of the efficacy of these antimalarial drugs in systematically selected sentinel sites to detect further development of resistance and to make timely national antimalarial drug policy changes. Copyright 2009 Elsevier B.V. All rights reserved.

Development of a pharmacovigilance safety monitoring tool for the rollout of single low-dose primaquine and artemether-lumefantrine to treat Plasmodium falciparum infections in Swaziland: a pilot study.

PubMed

Poirot, Eugenie; Soble, Adam; Ntshalintshali, Nyasatu; Mwandemele, Asen; Mkhonta, Nomcebo; Malambe, Calisile; Vilakati, Sibonakaliso; Pan, Sisi; Darteh, Sarah; Maphalala, Gugu; Brown, Joelle; Hwang, Jimee; Pace, Cheryl; Stergachis, Andy; Vittinghoff, Eric; Kunene, Simon; Gosling, Roland

2016-07-22

Countries remain reluctant to adopt the 2012 World Health Organization recommendation for single low-dose (0.25 mg/kg) primaquine (SLD PQ) for Plasmodium falciparum transmission-blocking due to concerns over drug-related haemolysis risk, especially among glucose-6-phosphate dehydrogenase-deficient (G6PDd) people, without evidence demonstrating that it can be safely deployed in their settings. Pharmacovigilance methods provide a systematic way of collecting safety data and supporting the rollout of SLD PQ. The Primaquine Roll Out Monitoring Pharmacovigilance Tool (PROMPT), comprising: (1) a standardized form to support the surveillance of possible adverse events following SLD PQ treatment; (2) a patient information card to enhance awareness of known adverse drug reactions of SLD PQ use; and (3) a database compiling recorded information, was developed and piloted. Data on patient characteristics, malaria diagnosis and treatment are collected. Blood samples are taken to measure haemoglobin (Hb) and test for G6PD deficiency. Active follow-up includes a repeat Hb measurement and adverse event monitoring on or near day 7. A 13-month prospective pilot study in two hospital facilities in Swaziland alongside the introduction of SLD PQ generated preliminary evidence on the feasibility and acceptability of PROMPT. PROMPT was well received by nurses as a simple, pragmatic approach to active surveillance of SLD PQ safety data. Of the 102 patients enrolled and administered SLD PQ, none were G6PDd. 93 (91.2 %) returned on or near day 7 for follow-up. Four (4.6 %) patients had falls in Hb ≥25 % from baseline, none of whom presented with signs or symptoms of anaemia. No patient's Hb fell below 7 g/dL and none required a blood transfusion. Of the 11 (11 %) patients who reported an adverse event over the study period, three were considered serious and included two deaths and one hospitalization; none were causally related to SLD PQ. Four non-serious adverse events were considered definitely, probably, or possibly related to SLD PQ. Improved pharmacovigilance to monitor and promote the safety of the WHO recommendation is needed. The successful application of PROMPT demonstrates its potential as an important tool to rapidly generate locally acquired safety data and support pharmacovigilance in resource-limited settings.

Research and Operational Support for the Study of Militarily Relevant Infectious Diseases of Interest to United States and Royal Thai Governments

DTIC Science & Technology

2004-01-01

resistance of exo-erythrocytic stage parasites to primaquine and tafenoquine ). B.2. Parasite Characterization: In the absence of an in vitro culture...Tropical Diseases, Mahidol University. Efforts are partnered with Pfizer and the NIH. Developed and approved a protocol to test tafenoquine (WR238605) in...completed by September 2004. Publication of previous dose-ranging studies of tafenoquine completed. Publication of prophylaxis study in the Royal

Pharmacological effects of primaquine ureas and semicarbazides on the central nervous system in mice and antimalarial activity in vitro.

PubMed

Kedzierska, Ewa; Orzelska, Jolanta; Perković, Ivana; Knežević, Danijel; Fidecka, Sylwia; Kaiser, Marcel; Zorc, Branka

2016-02-01

New primaquine (PQ) urea and semicarbazide derivatives 1-4 were screened for the first time for central nervous system (CNS) and antimalarial activity. Behavioural tests were performed on mice. In vitro cytotoxicity on L-6 cells and activity against erythrocytic stages of Plasmodium falciparum was determined. Compound 4 inhibited 'head-twitch' responses and decreased body temperature of mice, which suggests some involvement of the serotonergic system. Compound 4 protected mice against clonic seizures and was superior in the antimalarial test. A hybrid of two PQ urea 2 showed a strong antimalarial activity, confirming the previous findings of the high activity of bis(8-aminoquinolines) and other bisantimalarial drugs. All the compounds decreased the locomotor activity of mice, what suggests their weak depressive effects on the CNS, while PQ derivatives 1 and 2 increased amphetamine-induced hyperactivity. None of the compounds impaired coordination, what suggests a lack of their neurotoxicity. All the tested compounds presented an antinociceptive activity in the 'writhing' test. Compounds 3 and 4 were active in nociceptive tests, and those effects were reversed by naloxone. Compound 4 could be a useful lead compound in the development of CNS active agents and antimalarials, whereas compound 3 may be considered as the most promising lead for new antinociceptive agents. © 2015 Société Française de Pharmacologie et de Thérapeutique.

Safety of antimalarial medications for use while scuba diving in malaria Endemic Regions.

PubMed

Petersen, Kyle; Regis, David P

2016-01-01

Recreational diving occurs annually in areas of the world where malaria is endemic. The safety and efficacy of antimalarials for travelers in a hyperbaric environment is unknown. Of particular concern would be medications with adverse effects that could either mimic diving related illnesses such as barotrauma, decompression sickness (DCS) and gas toxicities, or increase the risk for such illnesses. We conducted a review of PubMed and Cochrane databases to determine rates of neurologic adverse effects or other effects from antimalarials that may be a problem in the diving environment. One case report was found on diving and mefloquine. Multiple case reports and clinical trials were found describing neurologic adverse effects of the major chemoprophylactic medications atovaquone/proguanil, chloroquine, doxycycline, mefloquine, and primaquine. Of the available literature, atovaquone/proguanil and doxycycline are most likely the safest agents and should be preferred; atovaquone/proguanil is superior due to reduced rates of sunburn in the marine environment. Primaquine also appears to be safe, but has reduced efficacy against P. falciparum ; mefloquine possesses the highest rate of neurologic side effects and therefore these agents should be limited to extreme cases of patients intolerant to other agents. Chloroquine appears unsafe in the hyperbaric environment and should be avoided. More studies are required to include database reviews of returned divers traveling to malaria endemic areas and randomized controlled trials in the hyperbaric environments.

Chemotherapy of Rodent Malaria.

DTIC Science & Technology

1985-07-01

Table 15 and detailed report sheets are appended as Tables 16 through 21. 3.1.1 WR 251855 AA This lepidine, an analogue of primaquine, is very active...has an ED9 0 of 2.7 mg/kg X 4 sc, a value very similar to that of chloroquine . When used against the moderately chloroquine -resistant NS line, the ED 9...0 value increased significantly to 25.5 mg/kg - a resistance factor of 9.4. Our highly chloroquine -resistant RC strain was also highly resistant to

Prophylaxis of Plasmodium falciparum Infection in a Human Challenge Model with WR 238605, a New 8-Aminoquinoline Antimalarial

PubMed Central

Brueckner, Ralf P.; Coster, Trinka; Wesche, David L.; Shmuklarsky, Moshe; Schuster, Brian G.

1998-01-01

The prophylactic efficacy of WR 238605, a primaquine analog, was studied with a human Plasmodium falciparum challenge model. A single oral dose of 600 mg, administered 1 day prior to challenge, successfully protected three of four subjects. The fourth subject developed mild, oligosymptomatic malaria on day 31, with drug concentrations one-half of those in the protected individuals. WR 238605 appears to be a promising prophylactic drug for P. falciparum malaria. PMID:9593172

Therapeutic Assessment of Primaquine for Radical Cure of Plasmodium vivax Malaria at Primary and Tertiary Care Centres in Southwestern India.

PubMed

Kumar, Rishikesh; Guddattu, Vasudeva; Saravu, Kavitha

2016-12-01

Acquaintance is scanty on primaquine (PQ) efficacy and Plasmodium vivax recurrence in Udupi district, Karnataka, India. We assessed the efficacy of 14 days PQ regimen (0.25 mg/kg/day) to prevent P. vivax recurrence. Microscopically, aparasitemic adults (≥18 years) after acute vivax malaria on day 28 were re-enrolled into 15 months' long follow-up study. A peripheral blood smear examination was performed with participants at every 1-2 month interval. A nested PCR test was performed to confirm the mono-infection with P. vivax . Of 114 participants, 28 (24.6%) recurred subsequently. The median (IQR) duration of the first recurrence was 3.1 (2.2-5.8) months which ranged from 1.2 to 15.1 months, including initial 28 days. Participants with history of vivax malaria had significantly higher risk of recurrence, with hazard ratio (HR) (95% CI) of 2.62 (1.24-5.54) ( P =0.012). Severity of disease (11.4%, 13/114) was not associated ( P =1.00) with recurrence. Of 28 recurrence cases, the nPCR proved that P. vivax mono-infection recurrence rate was at least 72.7% (16/22) at first recurrence. In Udupi district, PQ dose of 0.25 mg/kg/day over 14 days seems inadequate to prevent recurrence in substantial proportion of vivax malaria. Patients with a history of vivax malaria are at high risk of recurrences.

PFMDR1 POLYMORPHISMS INFLUENCE ON IN VITRO SENSITIVITY OF THAI PLASMODIUM FALCIPARUM ISOLATES TO PRIMAQUINE, SITAMAQUINE AND TAFENOQUINE.

PubMed

Kaewpruk, Napaporn; Tan-ariya, Peerapan; Ward, Stephen A; Sitthichot, Naruemon; Suwandittakul, Nantana; Mungthin, Mathirut

2016-05-01

Primaquine (PQ), an 8-aminoquinoline, is considered a tissue schizonticide drug for radical cure in vivax and ovale malaria, with minimal impact on asexual erythrocytic stages at therapeutic concentrations. Tafenoquine (TQ), a new 8-aminoquinoline analog of PQ, is active against both malaria parasite tissue and blood stages and is being promoted as a drug candidate for antimalarial chemotherapy and chemoprophylaxis and potential transmission blocking against Plasmodium vivax and P. falciparum. This study compared in vitro sensitivity of Thai P. falciparum isolates against three 8-aminoquinolines, PQ, TQ and sitamaquine (SQ), a related 8-aminoquinoline and assessed the importance of pfmdr1 polymorphism on the in vitro response. Seventy-eight laboratory adapted Thai P. falciparum isolates were evaluated for in vitro sensitivity to the three 8-aminoquinolines using a radioisotopic assay, and pfmdr1 polymorphisms were determined using PCR-based methods. All three drugs have weak antiplasmodial activity against asexual erythrocytic stage with SQ being the most potent by almost 10 folds. Cross susceptibility was observed in all three 8-aminoquinolines. Parasites containing pfmdr1 86Y, 184Y or 1034S allele exhibit significantly higher PQ IC₅₀. TQ sensitivity was reduced in those parasites containing pfmdr1 86Y, 1034S or 1042N allele. However, there was no significant influence of pfmdr1 alleles on SQ sensitivity. The data highlight unique differences among three representative 8-aminoquinoline drugs that may be useful in understanding their potential utility in antimalarial development.

Effects of 8-aminoquinolines on the ultrastructural morphology of Pneumocystis carinii.

PubMed Central

Goheen, M. P.; Bartlett, M. S.; Shaw, M. M.; Queener, S. F.; Smith, J. W.

1993-01-01

Primaquine and other 8-aminoquinolines are effective against Pneumocystis carinii in culture and animal models but the way(s) in which they affect P. carinii are not known. This study used transmission electron microscopy to observe early effects of 8-aminoquinolines on P. carinii grown with human embryonic lung fibroblasts in microcarrier suspension culture. The 8-aminoquinolines evaluated were primaquine and Walter Reed Army Institute for Research (WR) compounds WR6026, WR238605 and WR242511. Samples of P. carinii were taken at 0, 3, 6, 12, 24 and 48 hours from culture flasks containing selected concentrations of the drugs. Time matched samples from a parallel culture without drug served as controls. All the 8-aminoquinolines produced similar morphologic alterations of the internal structure of P. carinii. Initially, dilatation of the nuclear envelopes and membranous arrays arising from the reticular system were observed. Later, more organisms displayed large arrays of smooth membranous material often presenting a concentric membranous pattern. Subsequently, cellular organization was lost resulting in necrosis. At concentrations tested WR242511 appeared to be the most effective, producing alterations in many trophozoites after 6 hours of exposure; WR6026 appeared to be the least effective with some organisms unaffected after 48 hours. The changes observed are consistent with damage to the reticular system of P. carinii, which might be caused by oxidation by the 8-aminoquinolines or their metabolites. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:8398811

HIV-1 Vpu Blocks Recycling and Biosynthetic Transport of the Intrinsic Immunity Factor CD317/Tetherin To Overcome the Virion Release Restriction

PubMed Central

Schmidt, Sarah; Fritz, Joëlle V.; Bitzegeio, Julia; Fackler, Oliver T.; Keppler, Oliver T.

2011-01-01

ABSTRACT The intrinsic immunity factor CD317 (BST-2/HM1.24/tetherin) imposes a barrier to HIV-1 release at the cell surface that can be overcome by the viral protein Vpu. Expression of Vpu results in a reduction of CD317 surface levels; however, the mechanism of this Vpu activity and its contribution to the virological antagonism are incompletely understood. Here, we characterized the influence of Vpu on major CD317 trafficking pathways using quantitative antibody-based endocytosis and recycling assays as well as a microinjection/microscopy-based kinetic de novo expression approach. We report that HIV-1 Vpu inhibited both the anterograde transport of newly synthesized CD317 and the recycling of CD317 to the cell surface, while the kinetics of CD317 endocytosis remained unaffected. Vpu trapped trafficking CD317 molecules at the trans-Golgi network, where the two molecules colocalized. The subversion of both CD317 transport pathways was dependent on the highly conserved diserine S52/S56 motif of Vpu; however, it did not require recruitment of the diserine motif interactor and substrate adaptor of the SCF-E3 ubiquitin ligase complex, β-TrCP. Treatment of cells with the malaria drug primaquine resulted in a CD317 trafficking defect that mirrored that induced by Vpu. Importantly, primaquine could functionally replace Vpu as a CD317 antagonist and rescue HIV-1 particle release. PMID:21610122

Low risk of recurrence following artesunate-Sulphadoxine-pyrimethamine plus primaquine for uncomplicated Plasmodium falciparum and Plasmodium vivax infections in the Republic of the Sudan.

PubMed

Hamid, Muzamil Mahdi Abdel; Thriemer, Kamala; Elobied, Maha E; Mahgoub, Nouh S; Boshara, Salah A; Elsafi, Hassan M H; Gumaa, Suhaib A; Hamid, Tassneem; Abdelbagi, Hanadi; Basheir, Hamid M; Marfurt, Jutta; Chen, Ingrid; Gosling, Roly; Price, Ric N; Ley, Benedikt

2018-03-16

First-line schizontocidal treatment for uncomplicated malaria in the Republic of the Sudan is artesunate (total dose 12 mg/kg) plus Sulphadoxine/pyrimethamine (25/1.25 mg/kg) (AS/SP). Patients with Plasmodium vivax are also treated with 14 days primaquine (total dose 3.5 mg/kg) (PQ). The aim of this study was to assess the efficacy of the national policy. Patients above 1 year, with microscopy-confirmed, Plasmodium falciparum and/or P. vivax malaria were treated with AS/SP. Patients with P. falciparum were randomized to no primaquine (Pf-noPQ) or a single 0.25 mg/kg dose of PQ (Pf-PQ1). Patients with P. vivax received 14 days unsupervised 3.5 mg/kg PQ (Pv-PQ14) on day 2 or at the end of follow up (Pv-noPQ). Primary endpoint was the risk of recurrent parasitaemia at day 42. G6PD activity was measured by spectrophotometry and the Accessbio Biosensor™. 231 patients with P. falciparum (74.8%), 77 (24.9%) with P. vivax and 1 (0.3%) patient with mixed infection were enrolled. The PCR corrected cumulative risk of recurrent parasitaemia on day 42 was 3.8% (95% CI 1.2-11.2%) in the Pf-noPQ arm compared to 0.9% (95% CI 0.1-6.0%) in the Pf-PQ1 arm; (HR = 0.25 [95% CI 0.03-2.38], p = 0.189). The corresponding risks of recurrence were 13.4% (95% CI 5.2-31.9%) in the Pv-noPQ arm and 5.3% (95% CI 1.3-19.4%) in the Pv-PQ14 arm (HR 0.36 [95% CI 0.1-2.0], p = 0.212). Two (0.9%) patients had G6PD enzyme activity below 10%, 19 (8.9%) patients below 60% of the adjusted male median. Correlation between spectrophotometry and Biosensor™ was low (r s  = 0.330, p < 0.001). AS/SP remains effective for the treatment of P. falciparum and P. vivax. The addition of PQ reduced the risk of recurrent P. falciparum and P. vivax by day 42, although this did not reach statistical significance. The version of the Biosensor™ assessed is not suitable for routine use. Trial registration https://clinicaltrials.gov/ct2/show/NCT02592408.

CYP450 phenotyping and accurate mass identification of metabolites of the 8-aminoquinoline, anti-malarial drug primaquine.

PubMed

Pybus, Brandon S; Sousa, Jason C; Jin, Xiannu; Ferguson, James A; Christian, Robert E; Barnhart, Rebecca; Vuong, Chau; Sciotti, Richard J; Reichard, Gregory A; Kozar, Michael P; Walker, Larry A; Ohrt, Colin; Melendez, Victor

2012-08-02

The 8-aminoquinoline (8AQ) drug primaquine (PQ) is currently the only approved drug effective against the persistent liver stage of the hypnozoite forming strains Plasmodium vivax and Plasmodium ovale as well as Stage V gametocytes of Plasmodium falciparum. To date, several groups have investigated the toxicity observed in the 8AQ class, however, exact mechanisms and/or metabolic species responsible for PQ's haemotoxic and anti-malarial properties are not fully understood. In the present study, the metabolism of PQ was evaluated using in vitro recombinant metabolic enzymes from the cytochrome P450 (CYP) and mono-amine oxidase (MAO) families. Based on this information, metabolite identification experiments were performed using nominal and accurate mass measurements. Relative activity factor (RAF)-weighted intrinsic clearance values show the relative role of each enzyme to be MAO-A, 2C19, 3A4, and 2D6, with 76.1, 17.0, 5.2, and 1.7% contributions to PQ metabolism, respectively. CYP 2D6 was shown to produce at least six different oxidative metabolites along with demethylations, while MAO-A products derived from the PQ aldehyde, a pre-cursor to carboxy PQ. CYPs 2C19 and 3A4 produced only trace levels of hydroxylated species. As a result of this work, CYP 2D6 and MAO-A have been implicated as the key enzymes associated with PQ metabolism, and metabolites previously identified as potentially playing a role in efficacy and haemolytic toxicity have been attributed to production via CYP 2D6 mediated pathways.

Therapeutic assessment of chloroquine-primaquine combined regimen in adult cohort of Plasmodium vivax malaria from a tertiary care hospital in southwestern India.

PubMed

Rishikesh, Kumar; Kamath, Asha; Hande, Manjunatha H; Vidyasagar, Sudha; Acharya, Raviraja V; Acharya, Vasudeva; Belle, Jayaprakash; Shastry, Ananthakrishna B; Saravu, Kavitha

2015-08-11

Of late there have been accounts of therapeutic failure and chloroquine resistance in Plasmodium vivax malaria especially from Southeast Asian regions. The present study was conducted to assess the therapeutic efficacy of chloroquine-primaquine (CQ-PQ) combined regimen in a cohort of uncomplicated P. vivax mono-infection. A tertiary care hospital-based prospective study was conducted among adult cohort with mono-infection P. vivax malaria as per the World Health Organization's protocol of in vivo assessment of anti-malarial therapeutic efficacy. Participants were treated with CQ 25 mg/kg body weight divided over 3 days and PQ 0.25 mg/kg body weight daily for 2 weeks. Of a total of 125 participants recruited, 122 (97.6%) completed day 28 follow up, three (2.4%) participants were lost to follow-up. Eight patients (6.4%) were ascertained to have mixed P. vivax and Plasmodium falciparum infection by nested polymerase chain reaction test. The majority of subjects (56.8%, 71/125) became aparasitaemic on day 2 followed by 35.2% (44/125) on day 3, and 8% (10/125) on day 7, and remained so thereafter. Overall only one therapeutic failure (0.8%, 1/125) occurred on day 3 due to persistence of fever and parasitaemia. CQ-PQ combined regimen remains outstandingly effective for uncomplicated P. vivax malaria and should be retained as treatment of choice in the study region. One case of treatment failure indicates possible resistance which warrants constant vigilance and periodic surveillance.

Cytochrome P450 2D-mediated metabolism is not necessary for tafenoquine and primaquine to eradicate the erythrocytic stages of Plasmodium berghei.

PubMed

Milner, Erin E; Berman, Jonathan; Caridha, Diana; Dickson, Samuel P; Hickman, Mark; Lee, Patricia J; Marcsisin, Sean R; Read, Lisa T; Roncal, Norma; Vesely, Brian A; Xie, Lisa H; Zhang, Jing; Zhang, Ping; Li, Qigui

2016-12-07

Due to the ability of the 8-aminoquinolines (8AQs) to kill different stages of the malaria parasite, primaquine (PQ) and tafenoquine (TQ) are vital for causal prophylaxis and the eradication of erythrocytic Plasmodium sp. parasites. Recognizing the potential role of cytochrome (CYP) 450 2D6 in the metabolism and subsequent hepatic efficacy of 8-aminoquinolines, studies were designed to explore whether CYP2D-mediated metabolism was related to the ability of single-dose PQ and TQ to eliminate the asexual and sexual erythrocytic stages of Plasmodium berghei. An IV P. berghei sporozoite murine challenge model was utilized to directly compare causal prophylactic and erythrocytic activity (asexual and sexual parasite stages) dose-response relationships in C57BL/6 wild-type (WT) mice and subsequently compare the erythrocytic activity of PQ and TQ in WT and CYP2D knock-out (KO) mice. Single-dose administration of either 25 mg/kg TQ or 40 mg/kg PQ eradicated the erythrocytic stages (asexual and sexual) of P. berghei in C57BL WT and CYP2D KO mice. In WT animals, the apparent elimination of hepatic infections occurs at lower doses of PQ than are required to eliminate erythrocytic infections. In contrast, the minimally effective dose of TQ needed to achieve causal prophylaxis and to eradicate erythrocytic parasites was analogous. The genetic deletion of the CYP2D cluster does not affect the ability of PQ or TQ to eradicate the blood stages (asexual and sexual) of P. berghei after single-dose administration.

A randomized comparison of dihydroartemisinin-piperaquine and artesunate-amodiaquine combined with primaquine for radical treatment of vivax malaria in Sumatera, Indonesia.

PubMed

Pasaribu, Ayodhia Pitaloka; Chokejindachai, Watcharee; Sirivichayakul, Chukiat; Tanomsing, Naowarat; Chavez, Irwin; Tjitra, Emiliana; Pasaribu, Syahril; Imwong, Mallika; White, Nicholas J; Dondorp, Arjen M

2013-12-01

A high prevalence of chloroquine-resistant Plasmodium vivax in Indonesia has shifted first-line treatment to artemisinin-based combination therapies, combined with primaquine (PQ) for radical cure. Which combination is most effective and safe remains to be established. We conducted a prospective open-label randomized comparison of 14 days of PQ (0.25 mg base/kg) plus either artesunate-amodiaquine (AAQ + PQ) or dihydroartemisinin-piperaquine (DHP + PQ) for the treatment of uncomplicated monoinfection P. vivax malaria in North Sumatera, Indonesia. Patients were randomized and treatments were given without prior testing for G6PD status. The primary outcome was parasitological failure at day 42. Patients were followed up to 1 year. Between December 2010 and April 2012, 331 patients were included. After treatment with AAQ + PQ, recurrent infection occurred in 0 of 167 patients within 42 days and in 15 of 130 (11.5%; 95% confidence interval [CI], 6.6%-18.3%) within a year. With DHP + PQ, this was 1 of 164 (0.6%; 95% CI, 0.01%-3.4%) and 13 of 143 (9.1%; 95% CI, 4.9%-15.0%), respectively (P > .2). Intravascular hemolysis occurred in 5 patients, of which 3 males were hemizygous for the G6PD-Mahidol mutation. Minor adverse events were more frequent with AAQ + PQ. In North Sumatera, Indonesia, AAQ and DHP, both combined with PQ, were effective for blood-stage parasite clearance of uncomplicated P. vivax malaria. Both treatments were safe, but DHP + PQ was better tolerated. NCT01288820.

A Molecular Assay to Quantify Male and Female Plasmodium falciparum Gametocytes: Results From 2 Randomized Controlled Trials Using Primaquine for Gametocyte Clearance

PubMed Central

Stone, Will; Sawa, Patrick; Lanke, Kjerstin; Rijpma, Sanna; Oriango, Robin; Nyaurah, Maureen; Osodo, Paul; Osoti, Victor; Mahamar, Almahamoudou; Diawara, Halimatou; Woestenenk, Rob; Graumans, Wouter; van de Vegte-Bolmer, Marga; Bradley, John; Chen, Ingrid; Brown, Joelle; Siciliano, Giulia; Alano, Pietro; Gosling, Roly; Dicko, Alassane; Drakeley, Chris; Bousema, Teun

2017-01-01

Abstract Background Single low-dose primaquine (PQ) reduces Plasmodium falciparum infectivity before it impacts gametocyte density. Here, we examined the effect of PQ on gametocyte sex ratio as a possible explanation for this early sterilizing effect. Methods Quantitative reverse-transcription polymerase chain reaction assays were developed to quantify female gametocytes (targeting Pfs25 messenger RNA [mRNA]) and male gametocytes (targeting Pf3D7_1469900 mRNA) in 2 randomized trials in Kenya and Mali, comparing dihydroartemisinin-piperaquine (DP) alone to DP with PQ. Gametocyte sex ratio was examined in relation to time since treatment and infectivity to mosquitoes. Results In Kenya, the median proportion of male gametocytes was 0.33 at baseline. Seven days after treatment, gametocyte density was significantly reduced in the DP-PQ arm relative to the DP arm (females: 0.05% [interquartile range {IQR}, 0.0–0.7%] of baseline; males: 3.4% [IQR, 0.4%–32.9%] of baseline; P < .001). Twenty-four hours after treatment, gametocyte sex ratio became male-biased and was not significantly different between the DP and DP-PQ groups. In Mali, there was no significant difference in sex ratio between the DP and DP-PQ groups (>0.125 mg/kg) 48 hours after treatment, and gametocyte sex ratio was not associated with mosquito infection rates. Conclusions The early sterilizing effects of PQ may not be explained by the preferential clearance of male gametocytes and may be due to an effect on gametocyte fitness. PMID:28931236

Anti-trypanosomal activity of pentacyclic triterpenes isolated from Austroplenckia populnea (Celastraceae).

PubMed

Duarte, Lucienir Pains; Vieira Filho, Sidney Augusto; Silva, Grácia Divina de Fátima; de Sousa, José Rego; Pinto, Artur da Silveira

2002-01-01

Four pentacyclic triterpenes isolated from Austroplenckia populnea and four compounds of known anti T. cruzi or anti-malarial activity were tested. Of those triterpenes tested 20alpha-hydroxy-tingenone showed high activity, epikatonic acid was less active, while populnilic and populninic acids were inactive against the trypanosome of the subgenus Schizotrypanum tested. Benzonidazole, nifurtimox, ketoconazole and primaquine presented a remarkable dose-dependent inhibitory effect reaching practically to a total growth inhibition of the parasite at the end of incubation time. The trypanosome tested appear to be a suitable model for preliminary screen for anti T. (S.) cruzi compounds.

Unambiguous Synthesis and Prophylactic Antimalarial Activities of Imidazolidinedione Derivatives

DTIC Science & Technology

2005-05-04

pose special problems emphasis on development of tafenoquine (8-amino- for targeting the blood stages of malaria. Our product quinoline derivative...aminoquinoline drugs such as primaquine or ments, the recent priority was characterization of the tafenoquine 7 have activity against the liver stages of...40 2/5 2e (CH 2)4CH3 80 5/5 10 0/5 40 3/5 arteether 160 0/5 20 4/5 40 0/510 2/5 10 0/5 5 2/5 tafenoquine 160 toxicity 2f CH2CH2C=CH2 NDb death a One

Understanding human genetic factors influencing primaquine safety and efficacy to guide primaquine roll-out in a pre-elimination setting in southern Africa.

PubMed

Awandu, Shehu S; Raman, Jaishree; Makhanthisa, Takalani I; Kruger, Philip; Frean, John; Bousema, Teun; Niemand, Jandeli; Birkholtz, Lyn-Marie

2018-03-20

Primaquine (PQ) is recommended as an addition to standard malaria treatments in pre-elimination settings due to its pronounced activity against mature Plasmodium falciparum gametocytes, the parasite stage responsible for onward transmission to mosquitoes. However, PQ may trigger haemolysis in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. Additional human genetic factors, including polymorphisms in the human cytochrome P450 2D6 (CYP2D6) complex, may negatively influence the efficacy of PQ. This study assessed the prevalence of G6PD deficiency and two important CYP2D6 variants in representative pre-elimination settings in South Africa, to inform malaria elimination strategies. Volunteers (n = 248) attending six primary health care facilities in a malaria-endemic region of South Africa were enrolled between October and November 2015. G6PD status was determined phenotypically, using a CareStart™ G6PD rapid diagnostic test (RDT), and genotypically for two common African G6PD variants, namely A+ (A376G) and A- (G202A, A542T, G680T & T968C) by PCR, restriction fragment length polymorphisms (RFLP) and DNA sequencing. CYP2D6*4 and CYP2D6*17 variants were determined with PCR and RFLP. A prevalence of 13% (33/248) G6PD deficiency was observed in the cohort by G6PD RDT whilst by genotypic assessment, 32% (79/248) were A+ and 3.2% were A-, respectively. Among the male participants, 11% (6/55) were G6PD A- hemizygous; among females 1% (2/193) were G6PD A- homozygous and 16% (32/193) G6PD A- heterozygous. The strength of agreement between phenotyping and genotyping result was fair (Cohens Kappa κ = 0.310). The negative predictive value for the G6PD RDT for detecting hemizygous, homozygous and heterozygous individuals was 0.88 (95% CI 0.85-0.91), compared to the more sensitive genotyping. The CYP2D6*4 allele frequencies for CYP2D6*4 (inferred poor metabolizer phenotype) and CYP2D6*17 (inferred intermediate metabolizer phenotype) were 3.2 and 19.5%, respectively. Phenotypic and genotypic analyses both detected low prevalence of G6PD deficiency and the CYP2D6*4 variants. These findings, combined with increasing data confirming safety of single low-dose PQ in individuals with African variants of G6PD deficiency, supports the deployment of single low-dose PQ as a gametocytocidal drug. PQ would pose minimal risks to the study populations and could be a useful elimination strategy in the study area.

Prevalence of G6PD deficiency and associated haematological parameters in children from Botswana.

PubMed

Motshoge, Thato; Ababio, Grace; Aleksenko, Larysa; Souda, Sajini; Muthoga, Charles Waithaka; Mutukwa, Naledi; Tawe, Leabaneng; Ramatlho, Pleasure; Gabaitiri, Lesego; Chihanga, Simon; Mosweunyane, Tjantilili; Hamda, Shimeles; Moakofhi, Kentse; Ntebela, Davies; Peloewetse, Elias; Mazhani, Loeto; Pernica, Jeffrey M; Read, John; Quaye, Isaac K; Paganotti, Giacomo Maria

2018-05-17

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is commonly seen in malaria endemic areas as it is known to confer a selective advantage against malaria. Recently, we reported a high proportion of asymptomatic reservoir of Plasmodium vivax in Botswana, that calls for intervention with primaquine to achieve radical cure of vivax malaria. Considering that individuals with this enzyme deficiency are at risk of haemolysis following primaquine treatment, assessment of the population for the relative frequency of G6PD deficiency is imperative. Samples from 3019 children from all the districts of Botswana were successfully genotyped for polymorphisms at positions 202 and 376 of the G6PD gene. Haematological parameters were also measured. The overall population allele frequency (based on the hemizygous male frequency) was 2.30% (95% CI, 1.77-2.83), while the overall frequency of G6PD-deficient genotypes A- (hemizygote and homozygote genotypes only) was 1.26% (95% CI, 0.86-1.66). G6PD deficiency is spread in Botswana according to the historical prevalence of malaria with a North-West to South-East decreasing gradient trend. There was no association between G6PD status and P. vivax positivity. G6PD A- form was found to be associated with decreased RBC count and haemoglobin levels without a known cause or illness. In conclusion, we report for the first time the prevalence of G6PD deficiency in Botswana which is relevant for strategies in the malaria elimination campaign. Further work to examine the activities of the enzyme in the Botswana population at risk for malaria is warranted. Copyright © 2017. Published by Elsevier B.V.

Scalable Preparation and Differential Pharmacologic and Toxicologic Profiles of Primaquine Enantiomers

PubMed Central

Tekwani, Babu L.; Herath, H. M. T. Bandara; Sahu, Rajnish; Gettayacamin, Montip; Tungtaeng, Anchalee; van Gessel, Yvonne; Baresel, Paul; Wickham, Kristina S.; Bartlett, Marilyn S.; Fronczek, Frank R.; Melendez, Victor; Ohrt, Colin; Reichard, Gregory A.; McChesney, James D.; Rochford, Rosemary; Walker, Larry A.

2014-01-01

Hematotoxicity in individuals genetically deficient in glucose-6-phosphate dehydrogenase (G6PD) activity is the major limitation of primaquine (PQ), the only antimalarial drug in clinical use for treatment of relapsing Plasmodium vivax malaria. PQ is currently clinically used in its racemic form. A scalable procedure was developed to resolve racemic PQ, thus providing pure enantiomers for the first time for detailed preclinical evaluation and potentially for clinical use. These enantiomers were compared for antiparasitic activity using several mouse models and also for general and hematological toxicities in mice and dogs. (+)-(S)-PQ showed better suppressive and causal prophylactic activity than (−)-(R)-PQ in mice infected with Plasmodium berghei. Similarly, (+)-(S)-PQ was a more potent suppressive agent than (−)-(R)-PQ in a mouse model of Pneumocystis carinii pneumonia. However, at higher doses, (+)-(S)-PQ also showed more systemic toxicity for mice. In beagle dogs, (+)-(S)-PQ caused more methemoglobinemia and was toxic at 5 mg/kg of body weight/day given orally for 3 days, while (−)-(R)-PQ was well tolerated. In a novel mouse model of hemolytic anemia associated with human G6PD deficiency, it was also demonstrated that (−)-(R)-PQ was less hemolytic than (+)-(S)-PQ for the G6PD-deficient human red cells engrafted in the NOD-SCID mice. All these data suggest that while (+)-(S)-PQ shows greater potency in terms of antiparasitic efficacy in rodents, it is also more hematotoxic than (−)-(R)-PQ in mice and dogs. Activity and toxicity differences of PQ enantiomers in different species can be attributed to their different pharmacokinetic and metabolic profiles. Taken together, these studies suggest that (−)-(R)-PQ may have a better safety margin than the racemate in human. PMID:24913163

G6PD deficiency in Plasmodium falciparum and Plasmodium vivax malaria-infected Cambodian patients.

PubMed

Khim, Nimol; Benedet, Christophe; Kim, Saorin; Kheng, Sim; Siv, Sovannaroth; Leang, Rithea; Lek, Soley; Muth, Sinuon; Chea, Nguon; Chuor, Char Meng; Duong, Socheat; Kerleguer, Alexandra; Tor, Pety; Chim, Pheaktra; Canier, Lydie; Witkowski, Benoit; Taylor, Walter R J; Ménard, Didier

2013-05-28

Glucose-6-phosphate-dehydrogenase deficiency (G6PDd) rates are unknown in malaria-infected Cambodian patients. These data are key to a rational drug policy for malaria elimination of Plasmodium falciparum and Plasmodium vivax. From September 2010-2012, a two-year survey of G6PDd and haemoglobinopathies assessed by quantitative enzyme activity assay and haemoglobin electrophoresis, respectively, was conducted in malaria-infected patients presenting to 19 health centres throughout Cambodia. A total of 2,408 confirmed malaria patients of mean age 26.7 (range 2-81) years were recruited from mostly western Cambodia (n = 1,732, 71.9%); males outnumbered females by 3.9:1. Plasmodium falciparum was present in 1,443 (59.9%) and P. vivax in 965 (40.1%) patients. Mean G6PD activity was 11.6 (CI 95%: 11.4-11.8) U/g Hb, G6PDd was present in 13.9% of all patients (335/2,408) and severe G6PDd (including WHO Class I and II variants) was more common in western (158/1,732, 9.1%) versus eastern (21/414, 5.1%) Cambodia (P = 0.01). Of 997/2,408 (41.4%) had a haemoglobinopathy. Mean haemoglobin concentrations were inversely related to age: 8.1 g/dL < five years, 8.7 g/dL five to 14 years, and 10.4 g/dL >15 years (P <0.001). G6PDd prevalence, anaemia and haemoglobinopathies were common in malaria-infected patients. The deployment of primaquine in Cambodia should be preceded by primaquine safety studies paralleled with evaluations of easy to use tests to detect G6PDd.

G6PD deficiency in Plasmodium falciparum and Plasmodium vivax malaria-infected Cambodian patients

PubMed Central

2013-01-01

Background Glucose-6-phosphate-dehydrogenase deficiency (G6PDd) rates are unknown in malaria-infected Cambodian patients. These data are key to a rational drug policy for malaria elimination of Plasmodium falciparum and Plasmodium vivax. Methods From September 2010–2012, a two-year survey of G6PDd and haemoglobinopathies assessed by quantitative enzyme activity assay and haemoglobin electrophoresis, respectively, was conducted in malaria-infected patients presenting to 19 health centres throughout Cambodia. Results A total of 2,408 confirmed malaria patients of mean age 26.7 (range 2–81) years were recruited from mostly western Cambodia (n = 1,732, 71.9%); males outnumbered females by 3.9:1. Plasmodium falciparum was present in 1,443 (59.9%) and P. vivax in 965 (40.1%) patients. Mean G6PD activity was 11.6 (CI 95%: 11.4-11.8) U/g Hb, G6PDd was present in 13.9% of all patients (335/2,408) and severe G6PDd (including WHO Class I and II variants) was more common in western (158/1,732, 9.1%) versus eastern (21/414, 5.1%) Cambodia (P = 0.01). Of 997/2,408 (41.4%) had a haemoglobinopathy. Mean haemoglobin concentrations were inversely related to age: 8.1 g/dL < five years, 8.7 g/dL five to 14 years, and 10.4 g/dL >15 years (P <0.001). Conclusions G6PDd prevalence, anaemia and haemoglobinopathies were common in malaria-infected patients. The deployment of primaquine in Cambodia should be preceded by primaquine safety studies paralleled with evaluations of easy to use tests to detect G6PDd. PMID:23714236

Efficacy of Different Primaquine Regimens to Control Plasmodium falciparum Gametocytemia in Colombia.

PubMed

Arroyo-Arroyo, Maria; Arango, Eliana; Carmona-Fonseca, Jaime; Aristizabal, Beatriz; Yanow, Stephanie; Maestre, Amanda

2017-09-01

Treatment against Plasmodium falciparum malaria includes blood schizonticides to clear asexual parasites responsible for disease. The addition of gametocytocidal drugs can eliminate infectious sexual stages with potential for transmission and the World Health Organization recommends a single dose (SD) of primaquine (PQ) to this end. The efficacy of PQ at 0.75 mg/kg to suppress gametocytemia when administered in single or fractionated doses was evaluated. A clinical controlled study with an open-label design was executed; three groups of 20 subjects were studied sequentially. All subjects were treated with the standard dose of artemether-lumefantrine plus the total dose of 0.75 mg/kg of PQ administered (without previous G6PD testing) in three different ways: Group "0.75d-3" received 0.75 mg/kg on day 3; Group "0.50d-1 + 0.25d-3" received 0.50 mg/kg on day 1 and 0.25 mg/kg on day 3; Group "0.25d-1,2,3" received 0.25 mg/kg on days 1, 2, and 3. Subjects were evaluated on days 1, 4, and 7 by thick smear microscopy and quantitative polymerase chain reaction to determine the carriage of immature and mature gametocytes. There were no adverse events. The three schemes caused a marked reduction (75-85%) in prevalence of gametocytes on day 4 compared with day 1, but only the group that received 0.75 mg/kg on day 3 maintained the reduced gametocyte burden until day 7. None of the three treatments were able to clear gametocyte carriage on days 4 or 7, but the group that received the SD had the lowest prevalence of gametocytes (15%). Further studies are needed to establish a PQ regimen with complete efficacy against gametocytes.

A newly validated high-performance liquid chromatography method with diode array ultraviolet detection for analysis of the antimalarial drug primaquine in the blood plasma.

PubMed

Carmo, Ana Paula Barbosa do; Borborema, Manoella; Ribeiro, Stephan; De-Oliveira, Ana Cecilia Xavier; Paumgartten, Francisco Jose Roma; Moreira, Davyson de Lima

2017-01-01

Primaquine (PQ) diphosphate is an 8-aminoquinoline antimalarial drug with unique therapeutic properties. It is the only drug that prevents relapses of Plasmodium vivax or Plasmodium ovale infections. In this study, a fast, sensitive, cost-effective, and robust method for the extraction and high-performance liquid chromatography with diode array ultraviolet detection (HPLC-DAD-UV ) analysis of PQ in the blood plasma was developed and validated. After plasma protein precipitation, PQ was obtained by liquid-liquid extraction and analyzed by HPLC-DAD-UV with a modified-silica cyanopropyl column (250mm × 4.6mm i.d. × 5μm) as the stationary phase and a mixture of acetonitrile and 10mM ammonium acetate buffer (pH = 3.80) (45:55) as the mobile phase. The flow rate was 1.0mL·min-1, the oven temperature was 50OC, and absorbance was measured at 264nm. The method was validated for linearity, intra-day and inter-day precision, accuracy, recovery, and robustness. The detection (LOD) and quantification (LOQ) limits were 1.0 and 3.5ng·mL-1, respectively. The method was used to analyze the plasma of female DBA-2 mice treated with 20mg.kg-1 (oral) PQ diphosphate. By combining a simple, low-cost extraction procedure with a sensitive, precise, accurate, and robust method, it was possible to analyze PQ in small volumes of plasma. The new method presents lower LOD and LOQ limits and requires a shorter analysis time and smaller plasma volumes than those of previously reported HPLC methods with DAD-UV detection. The new validated method is suitable for kinetic studies of PQ in small rodents, including mouse models for the study of malaria.

Machine learning prioritizes synthesis of primaquine ureidoamides with high antimalarial activity and attenuated cytotoxicity.

PubMed

Levatić, Jurica; Pavić, Kristina; Perković, Ivana; Uzelac, Lidija; Ester, Katja; Kralj, Marijeta; Kaiser, Marcel; Rottmann, Matthias; Supek, Fran; Zorc, Branka

2018-02-25

Primaquine (PQ) is a commonly used drug that can prevent the transmission of Plasmodium falciparum malaria, however toxicity limits its use. We prepared five groups of PQ derivatives: amides 1a-k, ureas 2a-k, semicarbazides 3a,b, acylsemicarbazides 4a-k and bis-ureas 5a-v, and evaluated them for antimalarial activity in vitro against the erythrocytic stage of P. falciparum NF54. Particular substituents, such as trityl (in 2j and 5r) and methoxybenzhydryl (in 3b and 5v) were associated with a favorable cytotoxicity-to-activity ratio. To systematically link structural features of PQ derivatives to antiplasmodial activity, we performed a quantitative structure-activity relationship (QSAR) study using the Support Vector Machines machine learning method. This yielded a highly accurate statistical model (R 2  = 0.776 in cross-validation), which was used to prioritize novel candidate compounds. Seven novel PQ-ureidoamides 10a-g were synthesized and evaluated for activity, highlighting the benzhydryl ureidoamides 10e and 10f derived from p-chlorophenylglycine. Further experiments on human cell lines revealed that 10e and 10f are an order of magnitude less toxic than PQ in vitro while having antimalarial activity indistinguishable from PQ. The toxicity profile of novel compounds 10 toward human cells was particularly favorable when the glucose-6-phosphate dehydrogenase (G6PD) was inhibited, while toxicity of PQ was exacerbated by G6PD inhibition. Our work therefore highlights promising lead compounds for the development of effective antimalarial drugs that may also be safer for G6PD-deficient patients. In addition, we provide computational inferences of antimalarial activity and cytotoxicity for thousands of PQ-like molecular structures. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in southeast Iran: implications for malaria elimination.

PubMed

Tabatabaei, Seyed Mehdi; Salimi Khorashad, Alireza; Sakeni, Mohammad; Raeisi, Ahmad; Metanat, Zahra

2015-03-15

Glucose-6-phosphate dehydrogenase deficiency (G6PD) is an X-linked genetic disorder with a relatively high frequency in malaria-endemic regions. It is an obstacle to malaria elimination, as primaquine administered in the treatment of malaria can cause hemolysis in G6PD-deficient individuals. This study presents information on the prevalence of G6PD deficiency in Sistan and Balouchetsan province, which hosts more than 90% of Plasmodium vivax malaria cases in Iran. This type of information is needed for a successful malaria elimination program. A total of 526 students were randomly recruited through schools located in southeast Iran. Information was collected by interviewing the students using a structured questionnaire. Blood samples taken on filter papers were examined for G6PD deficiency using the fluorescent spot test. Overall, 72.8% (383/526) of the subjects showed normal G6PD enzyme function. Mild and severe G6PD deficiency was observed in 14.8% (78) and 12.2% (64) of subjects, respectively. A total 193/261 males (73.9%) and 190/265 (72%) females had normal enzyme activity. Mild G6PD deficiency was observed in 10.8% (28) and 18.9% (50) of male and female subjects, respectively. However, in comparison with females, a greater proportion of males showed severe enzyme deficiency (15.3% versus 9.1%). All these differences were statistically significant (p < 0.006). G6PD deficiency is highly prevalent in southeast Iran. G6PD-deficient individuals are susceptible to potentially severe and life-threatening hemolytic reactions after primaquine treatment. In order to achieve malaria elimination goals in the province, G6PD testing needs to be made routinely available within the health system.

Killing the hypnozoite – drug discovery approaches to prevent relapse in Plasmodium vivax

PubMed Central

Campo, Brice; Vandal, Omar; Wesche, David L.; Burrows, Jeremy N.

2015-01-01

The eradication of malaria will only be possible if effective, well-tolerated medicines kill hypnozoites in vivax and ovale malaria, and thus prevent relapses in patients. Despite progress in the 8-aminoquinoline series, with tafenoquine in Phase III showing clear benefits over primaquine, the drug discovery challenge to identify hypnozoiticidal or hypnozoite-activating compounds has been hampered by the dearth of biological tools and assays, which in turn has been limited by the immense scientific and logistical challenges associated with accessing relevant human tissue and sporozoites. This review summarises the existing drug discovery series and approaches concerning the goal to block relapse. PMID:25891812

Killing the hypnozoite--drug discovery approaches to prevent relapse in Plasmodium vivax.

PubMed

Campo, Brice; Vandal, Omar; Wesche, David L; Burrows, Jeremy N

2015-05-01

The eradication of malaria will only be possible if effective, well-tolerated medicines kill hypnozoites in vivax and ovale malaria, and thus prevent relapses in patients. Despite progress in the 8-aminoquinoline series, with tafenoquine in Phase III showing clear benefits over primaquine, the drug discovery challenge to identify hypnozoiticidal or hypnozoite-activating compounds has been hampered by the dearth of biological tools and assays, which in turn has been limited by the immense scientific and logistical challenges associated with accessing relevant human tissue and sporozoites. This review summarises the existing drug discovery series and approaches concerning the goal to block relapse.

Malaria parasite rates in Southern Rhodesia: May-September 1956.

PubMed

ALVES, W

1958-01-01

The author reports on malaria parasite rates found in the indigenous population of Southern Rhodesia after seven years of insecticide spraying. Although there is little or no overt malaria in sprayed areas, larvae of Anopheles gambiae are still found in certain foci. It is thought possible that the parasite rate is now so low that for practical purposes a break in transmission has been achieved, but the author points out that a dangerous potential source of infection exists in immigrant labour from other territories. Immigrants are now being treated on entry with up to 450 mg of amodiaquine and 45 mg of primaquine.

Malaria parasite rates in Southern Rhodesia: May-September 1956

PubMed Central

Alves, William

1958-01-01

The author reports on malaria parasite rates found in the indigenous population of Southern Rhodesia after seven years of insecticide spraying. Although there is little or no overt malaria in sprayed areas, larvae of Anopheles gambiae are still found in certain foci. It is thought possible that the parasite rate is now so low that for practical purposes a break in transmission has been achieved, but the author points out that a dangerous potential source of infection exists in immigrant labour from other territories. Immigrants are now being treated on entry with up to 450 mg of amodiaquine and 45 mg of primaquine. PMID:13585061

Single low-dose primaquine for blocking transmission of Plasmodium falciparum malaria - a proposed model-derived age-based regimen for sub-Saharan Africa.

PubMed

Taylor, W Robert; Naw, Htee Khu; Maitland, Kathryn; Williams, Thomas N; Kapulu, Melissa; D'Alessandro, Umberto; Berkley, James A; Bejon, Philip; Okebe, Joseph; Achan, Jane; Amambua, Alfred Ngwa; Affara, Muna; Nwakanma, Davis; van Geertruyden, Jean-Pierre; Mavoko, Muhindo; Lutumba, Pascal; Matangila, Junior; Brasseur, Philipe; Piola, Patrice; Randremanana, Rindra; Lasry, Estrella; Fanello, Caterina; Onyamboko, Marie; Schramm, Birgit; Yah, Zolia; Jones, Joel; Fairhurst, Rick M; Diakite, Mahamadou; Malenga, Grace; Molyneux, Malcolm; Rwagacondo, Claude; Obonyo, Charles; Gadisa, Endalamaw; Aseffa, Abraham; Loolpapit, Mores; Henry, Marie-Claire; Dorsey, Grant; John, Chandy; Sirima, Sodiomon B; Barnes, Karen I; Kremsner, Peter; Day, Nicholas P; White, Nicholas J; Mukaka, Mavuto

2018-01-18

In 2012, the World Health Organization recommended blocking the transmission of Plasmodium falciparum with single low-dose primaquine (SLDPQ, target dose 0.25 mg base/kg body weight), without testing for glucose-6-phosphate dehydrogenase deficiency (G6PDd), when treating patients with uncomplicated falciparum malaria. We sought to develop an age-based SLDPQ regimen that would be suitable for sub-Saharan Africa. Using data on the anti-infectivity efficacy and tolerability of primaquine (PQ), the epidemiology of anaemia, and the risks of PQ-induced acute haemolytic anaemia (AHA) and clinically significant anaemia (CSA), we prospectively defined therapeutic-dose ranges of 0.15-0.4 mg PQ base/kg for children aged 1-5 years and 0.15-0.5 mg PQ base/kg for individuals aged ≥6 years (therapeutic indices 2.7 and 3.3, respectively). We chose 1.25 mg PQ base for infants aged 6-11 months because they have the highest rate of baseline anaemia and the highest risks of AHA and CSA. We modelled an anthropometric database of 661,979 African individuals aged ≥6 months (549,127 healthy individuals, 28,466 malaria patients and 84,386 individuals with other infections/illnesses) by the Box-Cox transformation power exponential and tested PQ doses of 1-15 mg base, selecting dosing groups based on calculated mg/kg PQ doses. From the Box-Cox transformation power exponential model, five age categories were selected: (i) 6-11 months (n = 39,886, 6.03%), (ii) 1-5 years (n = 261,036, 45.46%), (iii) 6-9 years (n = 20,770, 3.14%), (iv) 10-14 years (n = 12,155, 1.84%) and (v) ≥15 years (n = 328,132, 49.57%) to receive 1.25, 2.5, 5, 7.5 and 15 mg PQ base for corresponding median (1st and 99th centiles) mg/kg PQ base of: (i) 0.16 (0.12-0.25), (ii) 0.21 (0.13-0.37), (iii) 0.25 (0.16-0.38), (iv) 0.26 (0.15-0.38) and (v) 0.27 (0.17-0.40). The proportions of individuals predicted to receive optimal therapeutic PQ doses were: 73.2 (29,180/39,886), 93.7 (244,537/261,036), 99.6 (20,690/20,770), 99.4 (12,086/12,155) and 99.8% (327,620/328,132), respectively. We plan to test the safety of this age-based dosing regimen in a large randomised placebo-controlled trial (ISRCTN11594437) of uncomplicated falciparum malaria in G6PDd African children aged 0.5 - 11 years. If the regimen is safe and demonstrates adequate pharmacokinetics, it should be used to support malaria elimination.

Artemisinin-based combination therapy for treating uncomplicated Plasmodium vivax malaria.

PubMed

Gogtay, Nithya; Kannan, Sridharan; Thatte, Urmila M; Olliaro, Piero L; Sinclair, David

2013-10-25

Plasmodium vivax is an important cause of malaria in many parts of Asia and South America, and parasite resistance to the standard treatment (chloroquine) is now high in some parts of Oceania. This review aims to assess the current treatment options in the light of increasing chloroquine resistance. To compare artemisinin-based combination therapies (ACTs) with alternative antimalarial regimens for treating acute uncomplicated P. vivax malaria. We searched the Cochrane Infectious Disease Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; LILACS; and the metaRegister of Controlled Trials (mRCT) up to 28 March 2013 using "vivax" and "arte* OR dihydroarte*" as search terms. Randomized controlled trials comparing ACTs versus standard therapy, or comparing alternative ACTs, in adults and children with uncomplicated P. vivax malaria. Two authors independently assessed trials for eligibility and risk of bias, and extracted data. We used recurrent parasitaemia prior to day 28 as a proxy for effective treatment of the blood stage parasite, and compared drug treatments using risk ratios (RR) and 95% confidence intervals (CIs). We used trials following patients for longer than 28 days to assess the duration of the post-treatment prophylactic effect of ACTs. We assessed the quality of the evidence using the GRADE approach. We included 14 trials, that enrolled 2592 participants, and were all conducted in Asia and Oceania between 2002 and 2011. ACTs versus chloroquine: ACTs clear parasites from the peripheral blood quicker than chloroquine monotherapy (parasitaemia after 24 hours of treatment: RR 0.42, 95% CI 0.36 to 0.50, four trials, 1652 participants, high quality evidence).In settings where chloroquine remains effective, ACTs are as effective as chloroquine at preventing recurrent parasitaemias before day 28 (RR 0.58, 95% CI 0.18 to 1.90, five trials, 1622 participants, high quality evidence). In four of these trials, recurrent parasitaemias before day 28 were very low following treatment with both chloroquine and ACTs. The fifth trial, from Thailand in 2011, found increased recurrent parasitaemias following treatment with chloroquine (9%), while they remained low following ACT (2%) (RR 0.25, 95% CI 0.09 to 0.66, one trial, 437 participants).ACT combinations with long half-lives probably also provide a longer prophylactic effect after treatment, with significantly fewer recurrent parasitaemias between day 28 and day 42 or day 63 (RR 0.57, 95% CI 0.40 to 0.82, three trials, 1066 participants, moderate quality evidence). One trial, from Cambodia, Thailand, India and Indonesia, gave additional primaquine to both treatment groups to reduce the risk of spontaneous relapses. Recurrent parasitaemias after day 28 were lower than seen in the trials that did not give primaquine, but the ACT still appeared to have an advantage (RR 0.27, 95% CI 0.08 to 0.94, one trial, 376 participants, low quality evidence). ACTs versus alternative ACTs: In high transmission settings, dihydroartemisinin-piperaquine is probably superior to artemether-lumefantrine, artesunate plus sulphadoxine-pyrimethamine and artesunate plus amodiaquine at preventing recurrent parasitaemias before day 28 (RR 0.20, 95% CI 0.08 to 0.49, three trials, 334 participants, moderate quality evidence).Dihydroartemisinin-piperaquine may also have an improved post-treatment prophylactic effect lasting for up to six weeks, and this effect may be present even when primaquine is also given to achieve radical cure (RR 0.21, 95% CI 0.10 to 0.46, two trials, 179 participants, low quality evidence).The data available from low transmission settings is too limited to reliably assess the relative effectiveness of ACTs. ACTs appear at least equivalent to chloroquine at effectively treating the blood stage of P. vivax infection. Even in areas where chloroquine remains effective, this finding may allow for simplified protocols for treating all forms of malaria with ACTs. In areas where chloroquine no longer cures the infection, ACTs offer an effective alternative.Dihydroartemisinin-piperaquine is the most studied ACT. It may provide a longer period of post-treatment prophylaxis than artemether-lumefantrine or artesunate plus amodiaquine. This effect may be clinically important in high transmission settings whether primaquine is also given or not.

Effects of liver-stage clearance by Primaquine on gametocyte carriage of Plasmodium vivax and P. falciparum.

PubMed

Wampfler, Rahel; Hofmann, Natalie E; Karl, Stephan; Betuela, Inoni; Kinboro, Benson; Lorry, Lina; Silkey, Mariabeth; Robinson, Leanne J; Mueller, Ivo; Felger, Ingrid

2017-07-01

Primaquine (PQ) is the only currently licensed antimalarial that prevents Plasmodium vivax (Pv) relapses. It also clears mature P. falciparum (Pf) gametocytes, thereby reducing post-treatment transmission. Randomized PQ treatment in a treatment-to-reinfection cohort in Papua New Guinean children permitted the study of Pv and Pf gametocyte carriage after radical cure and to investigate the contribution of Pv relapses. Children received radical cure with Chloroquine, Artemether-Lumefantrine plus either PQ or placebo. Blood samples were subsequently collected in 2-to 4-weekly intervals over 8 months. Gametocytes were detected by quantitative reverse transcription-PCR targeting pvs25 and pfs25. PQ treatment reduced the incidence of Pv gametocytes by 73%, which was comparable to the effect of PQ on incidence of blood-stage infections. 92% of Pv and 79% of Pf gametocyte-positive infections were asymptomatic. Pv and to a lesser extent Pf gametocyte positivity and density were associated with high blood-stage parasite densities. Multivariate analysis revealed that the odds of gametocytes were significantly reduced in mixed-species infections compared to single-species infections for both species (ORPv = 0.39 [95% CI 0.25-0.62], ORPf = 0.33 [95% CI 0.18-0.60], p<0.001). No difference between the PQ and placebo treatment arms was observed in density of Pv gametocytes or in the proportion of Pv infections that carried gametocytes. First infections after blood-stage and placebo treatment, likely caused by a relapsing hypnozoite, were equally likely to carry gametocytes than first infections after PQ treatment, likely caused by an infective mosquito bite. Pv relapses and new infections are associated with similar levels of gametocytaemia. Relapses thus contribute considerably to the Pv reservoir highlighting the importance of effective anti-hypnozoite treatment for efficient control of Pv. ClinicalTrials.gov NCT02143934.

Primaquine treatment and relapse in Plasmodium vivax malaria

PubMed Central

2016-01-01

The relapsing peculiarity of Plasmodium vivax is one of the prime reasons for sustained global malaria transmission. Global containment of P. vivax is more challenging and crucial compared to other species for achieving total malaria control/elimination. Primaquine (PQ) failure and P. vivax relapse is a major global public health concern. Identification and characterization of different relapse strains of P. vivax prevalent across the globe should be one of the thrust areas in malaria research. Despite renewed and rising global concern by researchers on this once ‘neglected’ species, research and development on the very topic of P. vivax reappearance remains inadequate. Many malaria endemic countries have not mandated routine glucose-6-phosphate dehydrogenase (G6PD) testing before initiating PQ radical cure in P. vivax malaria. This results in either no PQ prescription or thoughtless prescription and administration of PQ to P. vivax patients by healthcare providers without being concerned about patients’ G6PD status and associated complications. It is imperative to ascertain the G6PD status and optimum dissemination of PQ radical cure in all cases of P. vivax malaria across the globe. There persists a compelling need to develop/validate a rapid, easy-to-perform, easy-to-interpret, quality controllable, robust, and cost-effective G6PD assay. High-dose PQ of both standard and short duration appears to be safe and more effective for preventing relapses and should be practiced among patients with normal G6PD activity. Multicentric studies involving adequately representative populations across the globe with reference PQ dose must be carried out to determine the true distribution of PQ failure. Study proving role of cytochrome P450-2D6 gene in PQ metabolism and association of CYP2D6 metabolizer phenotypes and P. vivax relapse is of prime importance and should be carried forward in multicentric systems across the globe. PMID:27077309

Compliance with 14-day primaquine therapy for radical cure of vivax malaria--a randomized placebo-controlled trial comparing unsupervised with supervised treatment.

PubMed

Leslie, Toby; Rab, Mohammad Abdur; Ahmadzai, Hayat; Durrani, Naeem; Fayaz, Mohammad; Kolaczinski, Jan; Rowland, Mark

2004-03-01

The only available treatment that can eliminate the latent hypnozoite reservoir of vivax malaria is a 14 d course of primaquine (PQ). A potential problem with long-course chemotherapy is the issue of compliance after clinical symptoms have subsided. The present study, carried out at an Afghan refugee camp in Pakistan, between June 2000 and August 2001, compared 14 d treatment in supervised and unsupervised groups in which compliance was monitored by comparison of relapse rates. Clinical cases recruited by passive case detection were randomised by family to placebo, supervised, or unsupervised groups, and treated with chloroquine (25 mg/kg) over 3 days to eliminate erythrocytic stages. Individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency were excluded from the trial. Cases allocated to supervision were given directly observed treatment (0.25 mg PQ/kg body weight) once per day for 14 days. Cases allocated to the unsupervised group were provided with 14 PQ doses upon enrollment and strongly advised to complete the course. A total of 595 cases were enrolled. After 9 months of follow up PQ proved equally protective against further episodes of P. vivax in supervised (odds ratio 0.35, 95% CI 0.21-0.57) and unsupervised (odds ratio 0.37, 95% CI 0.23-0.59) groups as compared to placebo. All age groups on supervised or unsupervised treatment showed a similar degree of protection even though the risk of relapse decreased with age. The study showed that a presumed problem of poor compliance may be overcome with simple health messages even when the majority of individuals are illiterate and without formal education. Unsupervised treatment with 14-day PQ when combined with simple instruction can avert a significant amount of the morbidity associated with relapse in populations where G6PD deficiency is either absent or readily diagnosable.

Galactose-Anchored Gelatin Nanoparticles for Primaquine Delivery and Improved Pharmacokinetics: A Biodegradable and Safe Approach for Effective Antiplasmodial Activity against P. falciparum 3D7 and in Vivo Hepatocyte Targeting.

PubMed

Kumar, Hitesh; Gothwal, Avinash; Khan, Iliyas; Nakhate, Kartik T; Alexander, Amit; Ajazuddin; Singh, Vineeta; Gupta, Umesh

2017-10-02

Primaquine phosphate (PQ) is mainly used as a radical cure therapy to eradicate relapse of malaria at the liver stage, which is particularly caused by P. falciparum and P. vivax. In the present study, PQ-loaded galactosylated gelatin nanoparticles (Gel-LA-PQ-NPs) were formulated using a one-step desolvation technique. The mean particle size of Gel-LA-PQ-NPs was found to be 93.48 ± 6.36 nm with a zeta potential of 4.80 ± 0.20 mV having 69.90 ± 1.53% encapsulation efficiency. Electron microscopy demonstrated that the NPs were spherical in shape and uniformly distributed without any cluster formation. The in vitro release of PQ from Gel-LA-PQ-NPs has been facilitated in sustained manner, and the release was three times slower than the naïve drug. The prepared nanoparticles (Gel-LA-PQ-NPs) were significantly (p < 0.0001) less hemolytic than the pure drug PQ. The hematological ex vivo study further supported that the developed Gel-LA-PQ-NPs were safer than PQ. The in vitro antiplasmodium assay revealed that the IC 50 value against the blood stage of asexual P. falciparum 3D7 strains was significantly (p < 0.01) less (2.862 ± 0.103 μM) for Gel-LA-PQ-NPs than naïve PQ (3.879 ± 0.655 μM). In vivo pharmacokinetic parameters of Gel-LA-PQ-NPs such as half-life and AUC were significantly higher for Gel-LA-PQ-NPs, i.e., with higher bioavailability. Galactosylation of the NPs led to liver targeting of the PQ in animal studies. Approximately eight-fold higher accumulation of PQ was observed in liver compared to pure drug (i.e., PQ). Conclusively, the prepared galactosylated gelatin nanocarrier holds the promising potential and hepatic targetability of an antimalarial, maintaining its safety and biocompatibility.

Methylene blue induced morphological deformations in Plasmodium falciparum gametocytes: implications for transmission-blocking.

PubMed

Wadi, Ishan; Pillai, C Radhakrishna; Anvikar, Anupkumar R; Sinha, Abhinav; Nath, Mahendra; Valecha, Neena

2018-01-08

Malaria remains a global health problem despite availability of effective tools. For malaria elimination, drugs targeting sexual stages of Plasmodium falciparum need to be incorporated in treatment regimen along with schizonticidal drugs to interrupt transmission. Primaquine is recommended as a transmission blocking drug for its effect on mature gametocytes but is not extensively utilized because of associated safety concerns among glucose-6-phosphate dehydrogenase (G6PD) deficient patients. In present work, methylene blue, which is proposed as an alternative to primaquine is investigated for its gametocytocidal activity amongst Indian field isolates. An effort has been made to establish Indian field isolates of P. falciparum as in vitro model for gametocytocidal drugs screening. Plasmodium falciparum isolates were adapted to in vitro culture and induced to gametocyte production by hypoxanthine and culture was enriched for gametocyte stages using N-acetyl-glucosamine. Gametocytes were incubated with methylene blue for 48 h and stage specific gametocytocidal activity was evaluated by microscopic examination. Plasmodium falciparum field isolates RKL-9 and JDP-8 were able to reproducibly produce gametocytes in high yield and were used to screen gametocytocidal drugs. Methylene blue was found to target gametocytes in a concentration dependent manner by either completely eliminating gametocytes or rendering them morphologically deformed with mean IC 50 (early stages) as 424.1 nM and mean IC 50 (late stages) as 106.4 nM. These morphologically altered gametocytes appeared highly degenerated having shrinkage, distortions and membrane deformations. Field isolates that produce gametocytes in high yield in vitro can be identified and used to screen gametocytocidal drugs. These isolates should be used for validation of gametocytocidal hits obtained previously by using lab adapted reference strains. Methylene blue was found to target gametocytes produced from Indian field isolates and is proposed to be used as a gametocytocidal adjunct with artemisinin-based combination therapy. Further exploration of methylene blue in clinical studies amongst Indian population, including G6PD deficient patients, is recommended.

Sorting of endocytosed transferrin and asialoglycoprotein occurs immediately after internalization in HepG2 cells

PubMed Central

1987-01-01

After receptor-mediated uptake, asialoglycoproteins are routed to lysosomes, while transferrin is returned to the medium as apotransferrin. This sorting process was analyzed using 3,3'- diaminobenzidine (DAB) cytochemistry, followed by Percoll density gradient cell fractionation. A conjugate of asialoorosomucoid (ASOR) and horseradish peroxidase (HRP) was used as a ligand for the asialoglycoprotein receptor. Cells were incubated at 0 degree C in the presence of both 131I-transferrin and 125I-ASOR/HRP. Endocytosis of prebound 125I-ASOR/HRP and 131I-transferrin was monitored by cell fractionation on Percoll density gradients. Incubation of the cell homogenate in the presence of DAB and H2O2 before cell fractionation gave rise to a density shift of 125I-ASOR/HRP-containing vesicles due to HRP-catalyzed DAB polymerization. An identical change in density for 125I-transferrin and 125I-ASOR/HRP, induced by DAB cytochemistry, is taken as evidence for the concomitant presence of both ligands in the same compartment. At 37 degrees C, sorting of the two ligands occurred with a half-time of approximately 2 min, and was nearly completed within 10 min. The 125I-ASOR/HRP-induced shift of 131I-transferrin was completely dependent on the receptor-mediated uptake of 125I-ASOR/HRP in the same compartment. In the presence of a weak base (0.3 mM primaquine), the recycling of transferrin receptors was blocked. The cell surface transferrin receptor population was decreased within 6 min to 15% of its original size. DAB cytochemistry showed that sorting between endocytosed 131I-transferrin and 125I-ASOR/HRP was also blocked in the presence of primaquine. These results indicate that transferrin and asialoglycoprotein are taken up via the same compartments and that segregation of the transferrin-receptor complex and asialoglycoprotein occurs very efficiently soon after uptake. PMID:3032986

[Plasmodium malariae malaria with more than a 4-month incubation period: difficult to distinguish from a relapse of Plasmodium vivax malaria].

PubMed

Hase, Ryota; Uwamino, Yoshifumi; Muranaka, Kiyoharu; Tochitani, Kentaro; Sogi, Misa; Kitazono, Hidetaka; Hosokawa, Naoto

2013-07-01

We report herein on a case of Plasmodium malariae malaria with more than a 4-month incubation period. A 35-year-old Japanese man who first presented to our clinic with fever and history of travel to Papua New Guinea was suspected of having Plasmodium vivax malaria based on peripheral smear results. We admitted him and initiated treatment with mefloquine. After two days of therapy, he became afebrile. We discharged him, and P. vivax was later confirmed with PCR. We started mefloquine prophylaxis for a planned trip to Papua New Guinea. After his return, a standard dose of primaquine (15 mg x 14 days) was prescribed for a radical cure of P. vivax. About 4 months after his last visit to Papua New Guinea, he returned to our clinic with fever. We suspected a relapse of P. vivax malaria and admitted him for a second time. After two days of mefloquine therapy, his symptoms improved. We discharged him and restarted a higher dose of primaquine (30 mg x 14 days) therapy for a radical cure of P. vivax. Subsequently, the PCR test revealed the parasite was P. malariae and not P. vivax. Only 13 cases of Plasmodium malariae malaria have been reported in Japan during the past 10 years. Blood-stage schizonticides such as mefloquine is not active against the liver stage. Therefore, the use of these drugs for prophylaxis will not be effective for prevention of malaria if its liver stage is longer than the duration of effective chemoprophylaxis. Although the incubation period of P. malariae is typically 13 to 28 days, it occasionally lasts for months or even years. Careful attention should be given to the possibility that P. malariae occasionally has a long incubation period even in the absence of the hypnozoite stage.

Single-Dose Primaquine in a Preclinical Model of Glucose-6-Phosphate Dehydrogenase Deficiency: Implications for Use in Malaria Transmission-Blocking Programs

PubMed Central

Wickham, Kristina S.; Baresel, Paul C.; Sousa, Jason; Vuong, Chau T.; Reichard, Gregory A.; Campo, Brice; Tekwani, Babu L.; Walker, Larry A.

2016-01-01

Individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency (G6PDd) are at risk for developing hemolytic anemia when given the antimalarial drug primaquine (PQ). The WHO Evidence Review Group released a report suggesting that mass administration of a single dose of PQ at 0.25 mg of base/kg of body weight (mpk) (mouse equivalent of 3.125 mpk) could potentially reduce malaria transmission based on its gametocytocidal activity and could be safely administered to G6PD-deficient individuals, but there are limited safety data available confirming the optimum single dose of PQ. A single-dose administration of PQ was therefore assessed in our huRBC-SCID mouse model used to predict hemolytic toxicity with respect to G6PD deficiency. In this model, nonobese diabetic (NOD)/SCID mice are engrafted with human red blood cells (huRBC) from donors with the African or Mediterranean variant of G6PDd (A-G6PDd or Med-G6PDd, respectively) and demonstrate dose-dependent sensitivity to PQ. In mice engrafted with A-G6PD-deficient huRBC, single-dose PQ at 3.125, 6.25, or 12.5 mpk had no significant loss of huRBC compared to the vehicle control group. In contrast, in mice engrafted with Med-G6PDd huRBC, a single dose of PQ at 3.125, 6.25, or 12.5 mpk resulted in a significant, dose-dependent loss of huRBC compared to the value for the vehicle control group. Our data suggest that administration of a single low dose of 0.25 mpk of PQ could induce hemolytic anemia in Med-G6PDd individuals but that use of single-dose PQ at 0.25 mpk as a gametocytocidal drug to block transmission would be safe in areas where A-G6PDd predominates. PMID:27458212

Single-Dose Primaquine in a Preclinical Model of Glucose-6-Phosphate Dehydrogenase Deficiency: Implications for Use in Malaria Transmission-Blocking Programs.

PubMed

Wickham, Kristina S; Baresel, Paul C; Marcsisin, Sean R; Sousa, Jason; Vuong, Chau T; Reichard, Gregory A; Campo, Brice; Tekwani, Babu L; Walker, Larry A; Rochford, Rosemary

2016-10-01

Individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency (G6PDd) are at risk for developing hemolytic anemia when given the antimalarial drug primaquine (PQ). The WHO Evidence Review Group released a report suggesting that mass administration of a single dose of PQ at 0.25 mg of base/kg of body weight (mpk) (mouse equivalent of 3.125 mpk) could potentially reduce malaria transmission based on its gametocytocidal activity and could be safely administered to G6PD-deficient individuals, but there are limited safety data available confirming the optimum single dose of PQ. A single-dose administration of PQ was therefore assessed in our huRBC-SCID mouse model used to predict hemolytic toxicity with respect to G6PD deficiency. In this model, nonobese diabetic (NOD)/SCID mice are engrafted with human red blood cells (huRBC) from donors with the African or Mediterranean variant of G6PDd (A-G6PDd or Med-G6PDd, respectively) and demonstrate dose-dependent sensitivity to PQ. In mice engrafted with A-G6PD-deficient huRBC, single-dose PQ at 3.125, 6.25, or 12.5 mpk had no significant loss of huRBC compared to the vehicle control group. In contrast, in mice engrafted with Med-G6PDd huRBC, a single dose of PQ at 3.125, 6.25, or 12.5 mpk resulted in a significant, dose-dependent loss of huRBC compared to the value for the vehicle control group. Our data suggest that administration of a single low dose of 0.25 mpk of PQ could induce hemolytic anemia in Med-G6PDd individuals but that use of single-dose PQ at 0.25 mpk as a gametocytocidal drug to block transmission would be safe in areas where A-G6PDd predominates. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

A population survey of the glucose-6-phosphate dehydrogenase (G6PD) 563C>T (Mediterranean) mutation in Afghanistan.

PubMed

Jamornthanyawat, Natsuda; Awab, Ghulam R; Tanomsing, Naowarat; Pukrittayakamee, Sasithon; Yamin, Fazel; Dondorp, Arjen M; Day, Nicholas P J; White, Nicholas J; Woodrow, Charles J; Imwong, Mallika

2014-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzyme defect and an important problem in areas with Plasmodium vivax infection because of the risk of haemolysis following administration of primaquine to treat the liver forms of the parasite. We undertook a genotypic survey of 713 male individuals across nine provinces of Afghanistan in which malaria is found, four in the north and five in the east. RFLP typing at nucleotide position 563 detected 40 individuals with the Mediterranean mutation 563C>T, an overall prevalence of 5.6%. This varied according to self-reported ethnicity, with prevalence in the Pashtun/Pashai group of 33/369 (8.9%) compared to 7/344 individuals in the rest of the population (2.0%; p<0.001, Chi-squared test). Multivariate analysis of ethnicity and geographical location indicated an adjusted odds ratio of 3.50 (95% CI 1.36-9.02) for the Pashtun/Pashai group, while location showed only a trend towards higher prevalence in eastern provinces (adjusted odds ratio = 1.73, 0.73-4.13). Testing of known polymorphic markers (1311C>T in exon 11, and C93T in intron XI) in a subset of 82 individuals wild-type at C563 revealed a mixture of 3 haplotypes in the background population and was consistent with data from the 1000 Genomes Project and published studies. By comparison individuals with G6PD deficiency showed a highly skewed haplotype distribution, with 95% showing the CT haplotype, a finding consistent with relatively recent appearance and positive selection of the Mediterranean variant in Afghanistan. Overall, the data confirm that the Mediterranean variant of G6PD is common in many ethnic groups in Afghanistan, indicating that screening for G6PD deficiency is required in all individuals before radical treatment of P. vivax with primaquine.

Comparison of artemether-lumefantrine and chloroquine with and without primaquine for the treatment of Plasmodium vivax infection in Ethiopia: A randomized controlled trial

PubMed Central

Tadesse, Yehualashet; Melaku, Zenebe; Assef, Ashenafi; Kassa, Moges; Chatfield, Mark D.; Landman, Keren Z.; Chenet, Stella M.; Lucchi, Naomi W.; Udhayakumar, Venkatachalam; Zhou, Zhiyong; Shi, Ya Ping; Kachur, S. Patrick; Jima, Daddi; Kebede, Amha; Solomon, Hiwot; Mekasha, Addis; Alemayehu, Bereket Hailegiorgis; Malone, Joseph L.; Dissanayake, Gunewardena; Teka, Hiwot; Price, Ric N.

2017-01-01

Background Recent efforts in malaria control have resulted in great gains in reducing the burden of Plasmodium falciparum, but P. vivax has been more refractory. Its ability to form dormant liver stages confounds control and elimination efforts. To compare the efficacy and safety of primaquine regimens for radical cure, we undertook a randomized controlled trial in Ethiopia. Methods and findings Patients with normal glucose-6-phosphate dehydrogenase status with symptomatic P. vivax mono-infection were enrolled and randomly assigned to receive either chloroquine (CQ) or artemether-lumefantrine (AL), alone or in combination with 14 d of semi-supervised primaquine (PQ) (3.5 mg/kg total). A total of 398 patients (n = 104 in the CQ arm, n = 100 in the AL arm, n = 102 in the CQ+PQ arm, and n = 92 in the AL+PQ arm) were followed for 1 y, and recurrent episodes were treated with the same treatment allocated at enrolment. The primary endpoints were the risk of P. vivax recurrence at day 28 and at day 42. The risk of recurrent P. vivax infection at day 28 was 4.0% (95% CI 1.5%–10.4%) after CQ treatment and 0% (95% CI 0%–4.0%) after CQ+PQ. The corresponding risks were 12.0% (95% CI 6.8%–20.6%) following AL alone and 2.3% (95% CI 0.6%–9.0%) following AL+PQ. On day 42, the risk was 18.7% (95% CI 12.2%–28.0%) after CQ, 1.2% (95% CI 0.2%–8.0%) after CQ+PQ, 29.9% (95% CI 21.6%–40.5%) after AL, and 5.9% (95% CI 2.4%–13.5%) after AL+PQ (overall p < 0.001). In those not prescribed PQ, the risk of recurrence by day 42 appeared greater following AL treatment than CQ treatment (HR = 1.8 [95% CI 1.0–3.2]; p = 0.059). At the end of follow-up, the incidence rate of P. vivax was 2.2 episodes/person-year for patients treated with CQ compared to 0.4 for patients treated with CQ+PQ (rate ratio: 5.1 [95% CI 2.9–9.1]; p < 0.001) and 2.3 episodes/person-year for AL compared to 0.5 for AL+PQ (rate ratio: 6.4 [95% CI 3.6–11.3]; p < 0.001). There was no difference in the occurrence of adverse events between treatment arms. The main limitations of the study were the early termination of the trial and the omission of haemoglobin measurement after day 42, resulting in an inability to estimate the cumulative risk of anaemia. Conclusions Despite evidence of CQ-resistant P. vivax, the risk of recurrence in this study was greater following treatment with AL unless it was combined with a supervised course of PQ. PQ combined with either CQ or AL was well tolerated and reduced recurrence of vivax malaria by 5-fold at 1 y. Trial registration ClinicalTrials.gov NCT01680406 PMID:28510573

Tafenoquine, an Antiplasmodial 8-Aminoquinoline, Targets Leishmania Respiratory Complex III and Induces Apoptosis ▿

PubMed Central

Carvalho, Luis; Luque-Ortega, Juan Román; Manzano, José Ignacio; Castanys, Santiago; Rivas, Luis; Gamarro, Francisco

2010-01-01

Tafenoquine (TFQ), an 8-aminoquinoline analogue of primaquine, which is currently under clinical trial (phase IIb/III) for the treatment and prevention of malaria, may represent an alternative treatment for leishmaniasis. In this work, we have studied the mechanism of action of TFQ against Leishmania parasites. TFQ impaired the overall bioenergetic metabolism of Leishmania promastigotes, causing a rapid drop in intracellular ATP levels without affecting plasma membrane permeability. TFQ induced mitochondrial dysfunction through the inhibition of cytochrome c reductase (respiratory complex III) with a decrease in the oxygen consumption rate and depolarization of mitochondrial membrane potential. This was accompanied by ROS production, elevation of intracellular Ca2+ levels and concomitant nuclear DNA fragmentation. We conclude that TFQ targets Leishmania mitochondria, leading to an apoptosis-like death process. PMID:20837758

Tafenoquine, an antiplasmodial 8-aminoquinoline, targets leishmania respiratory complex III and induces apoptosis.

PubMed

Carvalho, Luis; Luque-Ortega, Juan Román; Manzano, José Ignacio; Castanys, Santiago; Rivas, Luis; Gamarro, Francisco

2010-12-01

Tafenoquine (TFQ), an 8-aminoquinoline analogue of primaquine, which is currently under clinical trial (phase IIb/III) for the treatment and prevention of malaria, may represent an alternative treatment for leishmaniasis. In this work, we have studied the mechanism of action of TFQ against Leishmania parasites. TFQ impaired the overall bioenergetic metabolism of Leishmania promastigotes, causing a rapid drop in intracellular ATP levels without affecting plasma membrane permeability. TFQ induced mitochondrial dysfunction through the inhibition of cytochrome c reductase (respiratory complex III) with a decrease in the oxygen consumption rate and depolarization of mitochondrial membrane potential. This was accompanied by ROS production, elevation of intracellular Ca(2+) levels and concomitant nuclear DNA fragmentation. We conclude that TFQ targets Leishmania mitochondria, leading to an apoptosis-like death process.

High frequency of diabetes and impaired fasting glucose in patients with glucose-6-phosphate dehydrogenase deficiency in the Western brazilian Amazon.

PubMed

Santana, Marli S; Monteiro, Wuelton M; Costa, Mônica R F; Sampaio, Vanderson S; Brito, Marcelo A M; Lacerda, Marcus V G; Alecrim, Maria G C

2014-07-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human genetic abnormalities, and it has a significant prevalence in the male population (X chromosome linked). The purpose of this study was to estimate the frequency of impaired fasting glucose and diabetes among G6PD-deficient persons in Manaus, Brazil, an area in the Western Brazilian Amazon to which malaria is endemic. Glucose-6-phosphate dehydrogenase-deficient males had more impaired fasting glucose and diabetes. This feature could be used as a screening tool for G6PD-deficient persons who are unable to use primaquine for the radical cure of Plasmodium vivax malaria. © The American Society of Tropical Medicine and Hygiene.

Quality of anti-malarials collected in the private and informal sectors in Guyana and Suriname

PubMed Central

2012-01-01

Background Despite a significant reduction in the number of malaria cases in Guyana and Suriname, this disease remains a major problem in the interior of both countries, especially in areas with gold mining and logging operations, where malaria is endemic. National malaria control programmes in these countries provide treatment to patients with medicines that are procured and distributed through regulated processes in the public sector. However, availability to medicines in licensed facilities (private sector) and unlicensed facilities (informal sector) is common, posing the risk of access to and use of non-recommended treatments and/or poor quality products. Methods To assess the quality of circulating anti-malarial medicines, samples were purchased in the private and informal sectors of Guyana and Suriname in 2009. The sampling sites were selected based on epidemiological data and/or distance from health facilities. Samples were analysed for identity, content, dissolution or disintegration, impurities, and uniformity of dosage units or weight variation according to manufacturer, pharmacopeial, or other validated method. Results Quality issues were observed in 45 of 77 (58%) anti-malarial medicines sampled in Guyana of which 30 failed visual & physical inspection and 18 failed quality control tests. The proportion of monotherapy and ACT medicines failing quality control tests was 43% (13/30) and 11% (5/47) respectively. A higher proportion of medicines sampled from the private sector 34% (11/32) failed quality control tests versus 16% (7/45) in the informal sector. In Suriname, 58 medicines were sampled, of which 50 (86%) were Artecom®, the fixed-dose combination of piperaquine-dihydroartemisinin-trimethoprim co-blistered with a primaquine phosphate tablet. All Artecom samples were found to lack a label claim for primaquine, thus failing visual and physical inspection. Conclusions The findings of the studies in both countries point to significant problems with the quality of anti-malarial medicines available in private and informal sector facilities as well as the availability of therapy not compliant with national treatment guidelines. They also stress the need to strengthen regulatory control efforts on the availability of anti-malarial medicines in these sectors and in endemic areas. PMID:22704709

Case report of Plasmodium ovale curtisi malaria in Sri Lanka: relevance for the maintenance of elimination status.

PubMed

Gunawardena, Sharmini; Daniels, Rachel F; Yahathugoda, Thishan C; Weerasooriya, Mirani V; Durfee, Katelyn; Volkman, Sarah K; Wirth, Dyann F; Karunaweera, Nadira D

2017-04-24

Following its recent certification as malaria-free, imported infections now pose the greatest threat for maintaining this status in Sri Lanka. Imported infections may also introduce species that are uncommon or not previously endemic to these areas. We highlight in this case report the increasing importance of less common malaria species such as Plasmodium ovale in elimination settings and discuss its relevance for the risk of malaria resurgence in the country. A 41-year-old patient from southern Sri Lanka was diagnosed with malaria after 8 days of fever. Microscopy of blood smears revealed parasites morphologically similar to P. vivax and the rapid diagnostic test was indicative of non-P. falciparum malaria. He was treated with chloroquine over 3 days and primaquine for 14 days. He was negative for malaria at a one-year follow-up. Molecular testing performed subsequently confirmed that infection was caused by P. ovale curtisi. The patient gave a history of P. vivax malaria treated with chloroquine and primaquine. He also provided a history of travel to malaria endemic regions, including residing in Liberia from May 2012 to November 2013, throughout which he was on weekly malaria prophylaxis with mefloquine. He had also visited India on an eight-day Buddhist pilgrimage tour in September 2014 without malaria prophylaxis. It is crucial that every case of malaria is investigated thoroughly and necessary measures taken to prevent re-introduction of malaria. Accurate molecular diagnostic techniques need to be established in Sri Lanka for the screening and diagnosis of all species of human malaria infections, especially those that may occur with low parasitemia and are likely to be undetected using the standard techniques currently in use. In addition, ascertaining whether an infection occurred through local transmission or by importation is critical in the implementation of an effective plan of action in the country. This new era emphasizes the global nature of regional malaria elimination. Increasing global surveillance and tool development are necessary in order to "fingerprint" parasites and identify their origin.

Where chloroquine still works: the genetic make-up and susceptibility of Plasmodium vivax to chloroquine plus primaquine in Bhutan.

PubMed

Wangchuk, Sonam; Drukpa, Tobgyel; Penjor, Kinley; Peldon, Tashi; Dorjey, Yeshey; Dorji, Kunzang; Chhetri, Vishal; Trimarsanto, Hidayat; To, Sheren; Murphy, Amanda; von Seidlein, Lorenz; Price, Ric N; Thriemer, Kamala; Auburn, Sarah

2016-05-12

Bhutan has made substantial progress in reducing malaria incidence. The national guidelines recommend chloroquine (CQ) and primaquine (PQ) for radical cure of uncomplicated Plasmodium vivax, but the local efficacy has not been assessed. The impact of cases imported from India on the genetic make-up of the local vivax populations is currently unknown. Patients over 4 years of age with uncomplicated P. vivax mono-infection were enrolled into a clinical efficacy study and molecular survey. Study participants received a standard dose of CQ (25 mg/kg over 3 days) followed by weekly review until day 28. On day 28 a 14-day regimen of PQ (0.25 mg/kg/day) was commenced under direct observation. After day 42, patients were followed up monthly for a year. The primary and secondary endpoints were risk of treatment failure at day 28 and at 1 year. Parasite genotyping was undertaken at nine tandem repeat markers, and standard population genetic metrics were applied to examine population diversity and structure in infections thought to be acquired inside or outside of Bhutan. A total of 24 patients were enrolled in the clinical study between April 2013 and October 2015. Eight patients (33.3 %) were lost to follow-up in the first 6 months and another eight patients lost between 6 and 12 months. No (0/24) treatment failures occurred by day 28 and no (0/8) parasitaemia was detected following PQ treatment. Some 95.8 % (23/24) of patients were aparasitaemic by day 2. There were no haemolytic or serious events. Genotyping was undertaken on parasites from 12 autochthonous cases and 16 suspected imported cases. Diversity was high (H E 0.87 and 0.90) in both populations. There was no notable differentiation between the autochthonous and imported populations. CQ and PQ remains effective for radical cure of P. vivax in Bhutan. The genetic analyses indicate that imported infections are sustaining the local vivax population, with concomitant risk of introducing drug-resistant strains.

Prevalence and molecular basis of glucose-6-phosphate dehydrogenase deficiency in Afghan populations: implications for treatment policy in the region

PubMed Central

2013-01-01

Background Glucose-6-phosphate dehydrogenase deficiency (G6PD), an x-linked inherited enzymopathy, is a barrier to malaria control because primaquine cannot be readily applied for radical cure in individuals with the condition. In endemic areas, including in Afghanistan, the G6PD status of vivax patients is not routinely determined so the drug is rarely, if ever, prescribed even though it is included as a recommended treatment in local, regional and global guidelines. This study assessed the prevalence and genotype of G6PD deficiency in Afghan populations and examined the need for routine G6PD testing as a malaria treatment and control tool. Methods A cross-sectional household survey was conducted using random sampling in five Afghan cities to determine the prevalence of G6PD deficiency in Afghan ethnic groups. Filter-paper blood spots were analysed for phenotypic G6PD deficiency using a fluorescent spot test. Molecular analysis was conducted to identify the genetic basis of the disorder. Results Overall, 45/1,436 (3.1%) people were G6PD deficient, 36/728 (5.0%) amongst males and 9/708 (1.3%) amongst females. Amongst males the prevalence was highest in the Pashtun ethnic group (10%, 26/260) while in Tajik males it was 8/250 (3.2%); in Hazara males it was 1/77 (1.3%) and in Uzbek males is was 0/125. Genetic testing in those with deficiency showed that all were of the Mediterranean type (Med-) characterized by a C-T change at codon 563 of the G6PD gene. Conclusion Prevalence of G6PD deficiency in Afghanistan varies considerably by ethnic group and is predominantly of the Mediterranean type. G6PD deficient individuals are susceptible to potentially severe and life-threatening haemolysis after standard primaquine treatment. If the aim of increasing access to radical treatment of vivax is to be successful reliable G6PD testing needs to be made routinely available within the health system. PMID:23834949

Methemoglobinemia Hemotoxicity of Some Antimalarial 8-Aminoquinoline Analogues and Their Hydroxylated Derivatives: Density Functional Theory Computation of Ionization Potentials.

PubMed

Ding, Yuanqing; Liu, Haining; Tekwani, Babu L; Nanayakkara, N P Dhammika; Khan, Ikhlas A; Walker, Larry A; Doerksen, Robert J

2016-07-18

The administration of primaquine (PQ), an essential drug for the treatment and radical cure of malaria, can lead to methemoglobin formation and life-threatening hemolysis for glucose-6-phosphate dehydrogenase deficient patients. The ionization potential (IP, a quantitative measure of the ability to lose an electron) of the metabolites generated by antimalarial 8-aminoquinoline (8-AQ) drugs like PQ has been believed to be correlated in part to this methemoglobinemia hemotoxicity: the lower the IP of an 8-AQ derivative, the higher the concentration of methemoglobin generated. In this work, demethoxylated primaquine (AQ02) was employed as a model, by intensive computation at the B3LYP-SCRF(PCM)/6-311++G**//B3LYP/6-31G** level in water, to study the effects of hydroxylation at various positions on the ionization potential. Compared to the parent AQ02, the IPs of AQ02's metabolites hydroxylated at N1', C5, and C7 were lower by 61, 30, and 19 kJ/mol, respectively, while differences in the IP relative to PQ were small for hydroxylation at all other positions. The C6 position, at which the IP of the hydroxylated metabolite was greater than that of AQ02, by 2 kJ/mol, was found to be unique. Several literature and proposed 8-AQ analogues were studied to evaluate substituent effects on their potential to generate methemoglobin, with the finding that hydroxylations at N1' and C5 contribute the most to the potential hemotoxicity of PQ-based antimalarials, whereas hydroxylation at C7 has little effect. Phenoxylation at C5 in PQ-based 8-AQs can block the hydroxylation at C5 and reduce the potential for methemoglobin generation, while -CF3 and chlorines attached to the phenolic ring can further reduce the risk. The H-shift at N1' during the cationization of hydroxylated metabolites of 8-AQs sharply decreased their IPs, but this effect can be significantly reduced by the introduction of an electron-withdrawing group to the quinoline core. The results and this approach may be utilized for the design of safer antimalarial 8-AQ analogues.

Tafenoquine and NPC-1161B require CYP 2D metabolism for anti-malarial activity: implications for the 8-aminoquinoline class of anti-malarial compounds

PubMed Central

2014-01-01

Background Tafenoquine (TQ) is an 8-aminoquinoline (8AQ) that has been tested in several Phase II and Phase III clinical studies and is currently in late stage development as an anti-malarial prophylactic agent. NPC-1161B is a promising 8AQ in late preclinical development. It has recently been reported that the 8AQ drug primaquine requires metabolic activation by CYP 2D6 for efficacy in humans and in mice, highlighting the importance of pharmacogenomics in the target population when administering primaquine. A logical follow-up study was to determine whether CYP 2D activation is required for other compounds in the 8AQ structural class. Methods In the present study, the anti-malarial activities of NPC-1161B and TQ were assessed against luciferase expressing Plasmodium berghei in CYP 2D knock-out mice in comparison with normal C57BL/6 mice (WT) and with humanized/CYP 2D6 knock-in mice by monitoring luminescence with an in vivo imaging system. These experiments were designed to determine the direct effects of CYP 2D metabolic activation on the anti-malarial efficacy of NPC-1161B and TQ. Results NPC-1161B and TQ exhibited no anti-malarial activity in CYP 2D knock-out mice when dosed at their ED100 values (1 mg/kg and 3 mg/kg, respectively) established in WT mice. TQ anti-malarial activity was partially restored in humanized/CYP 2D6 knock-in mice when tested at two times its ED100. Conclusions The results reported here strongly suggest that metabolism of NPC-1161B and TQ by the CYP 2D enzyme class is essential for their anti-malarial activity. Furthermore, these results may provide a possible explanation for therapeutic failures for patients who do not respond to 8AQ treatment for relapsing malaria. Because CYP 2D6 is highly polymorphic, variable expression of this enzyme in humans represents a significant pharmacogenomic liability for 8AQs which require CYP 2D metabolic activation for efficacy, particularly for large-scale prophylaxis and eradication campaigns. PMID:24386891

Assessment of the prophylactic activity and pharmacokinetic profile of oral tafenoquine compared to primaquine for inhibition of liver stage malaria infections

PubMed Central

2014-01-01

Background As anti-malarial drug resistance escalates, new safe and effective medications are necessary to prevent and treat malaria infections. The US Army is developing tafenoquine (TQ), an analogue of primaquine (PQ), which is expected to be more effective in preventing malaria in deployed military personnel. Methods To compare the prophylactic efficacy of TQ and PQ, a transgenic Plasmodium berghei parasite expressing the bioluminescent reporter protein luciferase was utilized to visualize and quantify parasite development in C57BL/6 albino mice treated with PQ and TQ in single or multiple regimens using a real-time in vivo imaging system (IVIS). As an additional endpoint, blood stage parasitaemia was monitored by flow cytometry. Comparative pharmacokinetic (PK) and liver distribution studies of oral and intravenous PQ and TQ were also performed. Results Mice treated orally with three doses of TQ at 5 mg/kg three doses of PQ at 25 mg/kg demonstrated no bioluminescence liver signal and no blood stage parasitaemia was observed suggesting both drugs showed 100% causal activity at the doses tested. Single dose oral treatment with 5 mg TQ or 25 mg of PQ, however, yielded different results as only TQ treatment resulted in causal prophylaxis in P. berghei sporozoite-infected mice. TQ is highly effective for causal prophylaxis in mice at a minimal curative single oral dose of 5 mg/kg, which is a five-fold improvement in potency versus PQ. PK studies of the two drugs administered orally to mice showed that the absolute bioavailability of oral TQ was 3.5-fold higher than PQ, and the AUC of oral TQ was 94-fold higher than oral PQ. The elimination half-life of oral TQ in mice was 28 times longer than PQ, and the liver tissue distribution of TQ revealed an AUC that was 188-fold higher than PQ. Conclusions The increased drug exposure levels and longer exposure time of oral TQ in the plasma and livers of mice highlight the lead quality attributes that explain the much improved efficacy of TQ when compared to PQ. PMID:24731238

Tafenoquine and NPC-1161B require CYP 2D metabolism for anti-malarial activity: implications for the 8-aminoquinoline class of anti-malarial compounds.

PubMed

Marcsisin, Sean R; Sousa, Jason C; Reichard, Gregory A; Caridha, Diana; Zeng, Qiang; Roncal, Norma; McNulty, Ronan; Careagabarja, Julio; Sciotti, Richard J; Bennett, Jason W; Zottig, Victor E; Deye, Gregory; Li, Qigui; Read, Lisa; Hickman, Mark; Dhammika Nanayakkara, N P; Walker, Larry A; Smith, Bryan; Melendez, Victor; Pybus, Brandon S

2014-01-03

Tafenoquine (TQ) is an 8-aminoquinoline (8AQ) that has been tested in several Phase II and Phase III clinical studies and is currently in late stage development as an anti-malarial prophylactic agent. NPC-1161B is a promising 8AQ in late preclinical development. It has recently been reported that the 8AQ drug primaquine requires metabolic activation by CYP 2D6 for efficacy in humans and in mice, highlighting the importance of pharmacogenomics in the target population when administering primaquine. A logical follow-up study was to determine whether CYP 2D activation is required for other compounds in the 8AQ structural class. In the present study, the anti-malarial activities of NPC-1161B and TQ were assessed against luciferase expressing Plasmodium berghei in CYP 2D knock-out mice in comparison with normal C57BL/6 mice (WT) and with humanized/CYP 2D6 knock-in mice by monitoring luminescence with an in vivo imaging system. These experiments were designed to determine the direct effects of CYP 2D metabolic activation on the anti-malarial efficacy of NPC-1161B and TQ. NPC-1161B and TQ exhibited no anti-malarial activity in CYP 2D knock-out mice when dosed at their ED100 values (1 mg/kg and 3 mg/kg, respectively) established in WT mice. TQ anti-malarial activity was partially restored in humanized/CYP 2D6 knock-in mice when tested at two times its ED100. The results reported here strongly suggest that metabolism of NPC-1161B and TQ by the CYP 2D enzyme class is essential for their anti-malarial activity. Furthermore, these results may provide a possible explanation for therapeutic failures for patients who do not respond to 8AQ treatment for relapsing malaria. Because CYP 2D6 is highly polymorphic, variable expression of this enzyme in humans represents a significant pharmacogenomic liability for 8AQs which require CYP 2D metabolic activation for efficacy, particularly for large-scale prophylaxis and eradication campaigns.

Assessment of the prophylactic activity and pharmacokinetic profile of oral tafenoquine compared to primaquine for inhibition of liver stage malaria infections.

PubMed

Li, Qigui; O'Neil, Michael; Xie, Lisa; Caridha, Diana; Zeng, Qiang; Zhang, Jing; Pybus, Brandon; Hickman, Mark; Melendez, Victor

2014-04-14

As anti-malarial drug resistance escalates, new safe and effective medications are necessary to prevent and treat malaria infections. The US Army is developing tafenoquine (TQ), an analogue of primaquine (PQ), which is expected to be more effective in preventing malaria in deployed military personnel. To compare the prophylactic efficacy of TQ and PQ, a transgenic Plasmodium berghei parasite expressing the bioluminescent reporter protein luciferase was utilized to visualize and quantify parasite development in C57BL/6 albino mice treated with PQ and TQ in single or multiple regimens using a real-time in vivo imaging system (IVIS). As an additional endpoint, blood stage parasitaemia was monitored by flow cytometry. Comparative pharmacokinetic (PK) and liver distribution studies of oral and intravenous PQ and TQ were also performed. Mice treated orally with three doses of TQ at 5 mg/kg three doses of PQ at 25 mg/kg demonstrated no bioluminescence liver signal and no blood stage parasitaemia was observed suggesting both drugs showed 100% causal activity at the doses tested. Single dose oral treatment with 5 mg TQ or 25 mg of PQ, however, yielded different results as only TQ treatment resulted in causal prophylaxis in P. berghei sporozoite-infected mice. TQ is highly effective for causal prophylaxis in mice at a minimal curative single oral dose of 5 mg/kg, which is a five-fold improvement in potency versus PQ. PK studies of the two drugs administered orally to mice showed that the absolute bioavailability of oral TQ was 3.5-fold higher than PQ, and the AUC of oral TQ was 94-fold higher than oral PQ. The elimination half-life of oral TQ in mice was 28 times longer than PQ, and the liver tissue distribution of TQ revealed an AUC that was 188-fold higher than PQ. The increased drug exposure levels and longer exposure time of oral TQ in the plasma and livers of mice highlight the lead quality attributes that explain the much improved efficacy of TQ when compared to PQ.

Prevalence and molecular basis of glucose-6-phosphate dehydrogenase deficiency in Afghan populations: implications for treatment policy in the region.

PubMed

Leslie, Toby; Moiz, Bushra; Mohammad, Nader; Amanzai, Omar; Ur Rasheed, Haroon; Jan, Sakhi; Siddiqi, Abdul M; Nasir, Amna; Beg, Mohammad A; Vink, Martijn

2013-07-08

Glucose-6-phosphate dehydrogenase deficiency (G6PD), an x-linked inherited enzymopathy, is a barrier to malaria control because primaquine cannot be readily applied for radical cure in individuals with the condition. In endemic areas, including in Afghanistan, the G6PD status of vivax patients is not routinely determined so the drug is rarely, if ever, prescribed even though it is included as a recommended treatment in local, regional and global guidelines. This study assessed the prevalence and genotype of G6PD deficiency in Afghan populations and examined the need for routine G6PD testing as a malaria treatment and control tool. A cross-sectional household survey was conducted using random sampling in five Afghan cities to determine the prevalence of G6PD deficiency in Afghan ethnic groups. Filter-paper blood spots were analysed for phenotypic G6PD deficiency using a fluorescent spot test. Molecular analysis was conducted to identify the genetic basis of the disorder. Overall, 45/1,436 (3.1%) people were G6PD deficient, 36/728 (5.0%) amongst males and 9/708 (1.3%) amongst females. Amongst males the prevalence was highest in the Pashtun ethnic group (10%, 26/260) while in Tajik males it was 8/250 (3.2%); in Hazara males it was 1/77 (1.3%) and in Uzbek males is was 0/125. Genetic testing in those with deficiency showed that all were of the Mediterranean type (Med-) characterized by a C-T change at codon 563 of the G6PD gene. Prevalence of G6PD deficiency in Afghanistan varies considerably by ethnic group and is predominantly of the Mediterranean type. G6PD deficient individuals are susceptible to potentially severe and life-threatening haemolysis after standard primaquine treatment. If the aim of increasing access to radical treatment of vivax is to be successful reliable G6PD testing needs to be made routinely available within the health system.

[Elimination in South-East Asia? The role of antimalarial drugs].

PubMed

Nosten, François

2016-03-01

Artemisinin resistance in P. falciparum is spreading in South East Asia and threatens the recent progresses made in the fight against malaria. A race against time has started to eliminate P.falciparum in this region before it becomes resistant to all available treatments. Antimalarials have a central role in the current elimination programme in eastern Burma on the border with Thailand. The combination of artemether and lumefantrine is used in association with primaquine for the early treatment of clinical cases. The slowly eliminated dihydro-artemisinin and piperaquine is the drug of choice in mass drug administration in the foci of high prevalence of sub-microscopic and asymptomatic infections. Initial results after 18 months of activities are promising: the participation of the population was excellent and there was a sharp reduction of P.falciparum incidence without evidence of worsening resistance.

Interactions between tafenoquine and artemisinin-combination therapy partner drug in asexual and sexual stage Plasmodium falciparum.

PubMed

Kemirembe, Karen; Cabrera, Mynthia; Cui, Liwang

2017-08-01

The 8-aminoquinoline tafenoquine (TFQ), a primaquine derivative, is currently in late-stage clinical development for the radical cure of P. vivax. Here drug interactions between TFQ and chloroquine and six artemisinin-combination therapy (ACT) partner drugs in P. falciparum asexual stages and gametocytes were investigated. TFQ was mostly synergistic with the ACT-partner drugs in asexual parasites regardless of genetic backgrounds. However, at fixed ratios of 1:3, 1:1 and 3:1, TFQ only interacted synergistically with naphthoquine, pyronaridine and piperaquine in gametocytes. This study indicated that TFQ and ACT-partner drugs will likely have increased potency against asexual stages of the malaria parasites, whereas some drugs may interfere with each other against the P. falciparum gametocytes. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

4(1H)-Quinolones with liver stage activity against Plasmodium berghei.

PubMed

Lacrue, Alexis N; Sáenz, Fabián E; Cross, R Matthew; Udenze, Kenneth O; Monastyrskyi, Andrii; Stein, Steven; Mutka, Tina S; Manetsch, Roman; Kyle, Dennis E

2013-01-01

With the exception of primaquine, tafenoquine, and atovaquone, there are very few antimalarials that target liver stage parasites. In this study, a transgenic Plasmodium berghei parasite (1052Cl1; PbGFP-Luc(con)) that expresses luciferase was used to assess the anti-liver stage parasite activity of ICI 56,780, a 7-(2-phenoxyethoxy)-4(1H)-quinolone (PEQ), as well as two 3-phenyl-4(1H)-quinolones (P4Q), P4Q-146 and P4Q-158, by using bioluminescent imaging (BLI). Results showed that all of the compounds were active against liver stage parasites; however, ICI 56,780 and P4Q-158 were the most active, with low nanomolar activity in vitro and causal prophylactic activity in vivo. This potent activity makes these compounds ideal candidates for advancement as novel antimalarials.

Synthesis of 4-alkyl and 4-(beta-alkylvinyl) derivatives of primaquine as potential antimalarials.

PubMed

Carroll, F I; Berrang, B D; Linn, C P

1979-11-01

4(beta-Alkylvinyl)-6-methoxy-8-nitroquinolines (6) were prepared from 6-methoxy-8-nitroquinoline-4-carboxaldehyde (5) via a Wittig reaction. Stannous chloride reduction of 6 gave 4-(beta-alkylvinyl)-8-amino-6-methoxyquinolines (8), whereas catalytic reduction of 6 using Raney nickel catalyst gave 4-alkyl-8-amino-6-methoxyquinolines (7). Alkylation of 7 and 8 with 4-iodo-1-phthalimidopentane, followed by removal of the phthaloyl-protecting group with hydrazine, gave 4-alkyl and 4-(beta-alkylvinyl) derivatives of primiquine, respectively. These compounds were evaluated for antimalarial activity against P. berghei and P. berghei yoelii in mice and against P. cynomolgi in rhesus monkeys. Several of the compounds were active in the P. bergheii yoelii screen. None of the compounds showed significant activity in the other two screens.

Quinine conjugates and quinine analogues as potential antimalarial agents.

PubMed

Jones, Rachel A; Panda, Siva S; Hall, C Dennis

2015-06-05

Malaria is a tropical disease, prevalent in Southeast Asia and Africa, resulting in over half a million deaths annually; efforts to develop new antimalarial agents are therefore particularly important. Quinine continues to play a role in the fight against malaria, but quinoline derivatives are more widely used. Drugs based on the quinoline scaffold include chloroquine and primaquine, which are able to act against the blood and liver stages of the parasite's life cycle. The purpose of this review is to discuss reported biologically active compounds based on either the quinine or quinoline scaffold that may have enhanced antimalarial activity. The review emphasises hybrid molecules, and covers advances made in the last five years. The review is divided into three sections: modifications to the quinine scaffold, modifications to aminoquinolines and finally metal-containing antimalarial compounds. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Costs and Cost-Effectiveness of Plasmodium vivax Control.

PubMed

White, Michael T; Yeung, Shunmay; Patouillard, Edith; Cibulskis, Richard

2016-12-28

The continued success of efforts to reduce the global malaria burden will require sustained funding for interventions specifically targeting Plasmodium vivax The optimal use of limited financial resources necessitates cost and cost-effectiveness analyses of strategies for diagnosing and treating P. vivax and vector control tools. Herein, we review the existing published evidence on the costs and cost-effectiveness of interventions for controlling P. vivax, identifying nine studies focused on diagnosis and treatment and seven studies focused on vector control. Although many of the results from the much more extensive P. falciparum literature can be applied to P. vivax, it is not always possible to extrapolate results from P. falciparum-specific cost-effectiveness analyses. Notably, there is a need for additional studies to evaluate the potential cost-effectiveness of radical cure with primaquine for the prevention of P. vivax relapses with glucose-6-phosphate dehydrogenase testing. © The American Society of Tropical Medicine and Hygiene.

Costs and Cost-Effectiveness of Plasmodium vivax Control

PubMed Central

White, Michael T.; Yeung, Shunmay; Patouillard, Edith; Cibulskis, Richard

2016-01-01

The continued success of efforts to reduce the global malaria burden will require sustained funding for interventions specifically targeting Plasmodium vivax. The optimal use of limited financial resources necessitates cost and cost-effectiveness analyses of strategies for diagnosing and treating P. vivax and vector control tools. Herein, we review the existing published evidence on the costs and cost-effectiveness of interventions for controlling P. vivax, identifying nine studies focused on diagnosis and treatment and seven studies focused on vector control. Although many of the results from the much more extensive P. falciparum literature can be applied to P. vivax, it is not always possible to extrapolate results from P. falciparum–specific cost-effectiveness analyses. Notably, there is a need for additional studies to evaluate the potential cost-effectiveness of radical cure with primaquine for the prevention of P. vivax relapses with glucose-6-phosphate dehydrogenase testing. PMID:28025283

Review: Malaria Chemoprophylaxis for Travelers to Latin America

PubMed Central

Steinhardt, Laura C.; Magill, Alan J.; Arguin, Paul M.

2011-01-01

Because of recent declining malaria transmission in Latin America, some authorities have recommended against chemoprophylaxis for most travelers to this region. However, the predominant parasite species in Latin America, Plasmodium vivax, can form hypnozoites sequestered in the liver, causing malaria relapses. Additionally, new evidence shows the potential severity of vivax infections, warranting continued consideration of prophylaxis for travel to Latin America. Individualized travel risk assessments are recommended and should consider travel locations, type, length, and season, as well as probability of itinerary changes. Travel recommendations might include no precautions, mosquito avoidance only, or mosquito avoidance and chemoprophylaxis. There are a range of good options for chemoprophylaxis in Latin America, including atovaquone-proguanil, doxycycline, mefloquine, and—in selected areas—chloroquine. Primaquine should be strongly considered for nonpregnant, G6PD-nondeficient patients traveling to vivax-endemic areas of Latin America, and it has the added benefit of being the only drug to protect against malaria relapses. PMID:22144437

Estimation of the Antirelapse Efficacy of Tafenoquine, Using Plasmodium vivax Genotyping

PubMed Central

Beck, Hans-Peter; Wampfler, Rahel; Carter, Nick; Koh, Gavin; Osorio, Lyda; Rueangweerayut, Ronnatrai; Krudsood, Srivcha; Lacerda, Marcus V.; Llanos-Cuentas, Alejandro; Duparc, Stephan; Rubio, Justin P.; Green, Justin A.

2016-01-01

Prevention of relapse of Plasmodium vivax infection is a key treatment goal in malaria. Use of P. vivax genotyping in a multicenter, double-blind, randomized, placebo-controlled phase 2b study in Peru, India, Thailand, and Brazil allowed determination of genetically heterologous or homologous P. vivax infection recurrence following receipt of chloroquine plus one of 4 doses of tafenoquine (50, 100, 300, or 600 mg) or chloroquine plus primaquine, compared with receipt of chloroquine alone. The antihypnozoite efficacy of tafenoquine was evident as a reduction in homologous recurrences of P. vivax infection as drug doses were increased. No clear dose-response pattern was evident for heterologous recurrences of P. vivax infection. Rates of homologous recurrence of P. vivax infection appear to be clinically useful for comparing drug efficacy for the prevention of P. vivax infection relapse. Clinical Trials Registration. NCT01376167. PMID:26500351

Estimation of the Antirelapse Efficacy of Tafenoquine, Using Plasmodium vivax Genotyping.

PubMed

Beck, Hans-Peter; Wampfler, Rahel; Carter, Nick; Koh, Gavin; Osorio, Lyda; Rueangweerayut, Ronnatrai; Krudsood, Srivcha; Lacerda, Marcus V; Llanos-Cuentas, Alejandro; Duparc, Stephan; Rubio, Justin P; Green, Justin A

2016-03-01

Prevention of relapse of Plasmodium vivax infection is a key treatment goal in malaria. Use of P. vivax genotyping in a multicenter, double-blind, randomized, placebo-controlled phase 2b study in Peru, India, Thailand, and Brazil allowed determination of genetically heterologous or homologous P. vivax infection recurrence following receipt of chloroquine plus one of 4 doses of tafenoquine (50, 100, 300, or 600 mg) or chloroquine plus primaquine, compared with receipt of chloroquine alone. The antihypnozoite efficacy of tafenoquine was evident as a reduction in homologous recurrences of P. vivax infection as drug doses were increased. No clear dose-response pattern was evident for heterologous recurrences of P. vivax infection. Rates of homologous recurrence of P. vivax infection appear to be clinically useful for comparing drug efficacy for the prevention of P. vivax infection relapse. NCT01376167. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America.

Glucose-6-phosphate dehydrogenase deficiency and antimalarial drug development.

PubMed

Beutler, Ernest; Duparc, Stephan

2007-10-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is relatively common in populations exposed to malaria. This deficiency appears to provide some protection from this infection, but it can also cause hemolysis after administration of some antimalarial drugs, especially primaquine. The risk of drug-induced G6PD deficiency-related hemolysis depends on a number of factors including the G6PD variant, the drug and drug dosage schedule, patient status, and disease factors. Although a great deal is known about the molecular biology of G6PD, determining the potential for drug-induced hemolysis in the clinical setting is still challenging. This report discusses the potential strategies for assessing drug-induced G6PD deficiency-related hemolytic risk preclinically and in early clinical trials. Additionally, the issues important for conducting larger clinical trials in populations in which G6PD deficiency is prevalent are examined, with a particular focus on antimalarial drug development.

Effectiveness of combined chloroquine and primaquine treatment in 14 days versus intermittent single dose regimen, in an open, non-randomized, clinical trial, to eliminate Plasmodium vivax in southern Mexico.

PubMed

Gonzalez-Ceron, Lilia; Rodriguez, Mario H; Sandoval, Marco A; Santillan, Frida; Galindo-Virgen, Sonia; Betanzos, Angel F; Rosales, Angel F; Palomeque, Olga L

2015-10-30

In Mexico, combined chloroquine (CQ) and primaquine (PQ) treatment has been used since the late 1950s to treat Plasmodium vivax infections. Although malaria transmission has declined, current treatment strategies must be evaluated to advance towards malaria elimination. The clinical and parasitological outcome of treating symptomatic P. vivax with the 14-day (T14) treatment or intermittent single dose (ISD) regimen was evaluated in southern Mexico between February 2008 and September 2010. Patients over 12 months old with P. vivax mono-infection and asexual parasitaemia ≥500 parasites/µl were treated under supervision. After diagnosis (day 0), treatment began immediately. T14 patients received CQ for 3 days (10, 10 and 5 mg/kg) and PQ daily for 14 days (0.25 mg/kg), while ISD patients received a single dose of CQ (10 mg/kg) and PQ (0.75 mg/kg) on days 0, 30, 60, 180, 210, and 240. Follow-up was done by observing clinical and laboratory (by microscopy, serology and PCR) outcome, considering two endpoints: primary blood infection clearance and clinical response at ~28 days, and the incidence of recurrent blood infection during 12 months. Parasite genotypes of primary/recurrent blood infections were analysed. During the first 28 days, no differences in parasite clearance or clinical outcome were observed between T14 (86 patients) and ISD (67 patients). On day 3, 95 % of patients in both groups showed no blood parasites, and no recurrences were detected on days 7-28. Contrarily, the therapeutic effectiveness (absence of recurrent parasitaemia) was distinct for T14 versus ISD at 12 months: 83.7 versus 50 %, respectively (p = 0.000). Symptomatic and asymptomatic infections were recorded on days 31-352. Some parasite recurrences were detected by PCR and/or serological testing. T14 was effective for opportune elimination of the primary blood infection and preventing relapse episodes. The first single dose of CQ-PQ eliminated primary blood infection as efficiently as the initial three-dose scheme of T14, but the ISD regimen should be abandoned. A single combined dose administered to symptomatic patients in remote areas while awaiting parasitological diagnosis may contribute to halting P. vivax transmission. Alternatives for meeting the challenge of T14 supervision are discussed. NIH-USA, ClinicalTrial.gov Identifier: NCT02394197.

Tools for mass screening of G6PD deficiency: validation of the WST8/1-methoxy-PMS enzymatic assay in Uganda

PubMed Central

2013-01-01

Background The distribution of the enzymopathy glucose-6-phosphate dehydrogenase (G6PD) deficiency is linked to areas of high malaria endemicity due to its association with protection from disease. G6PD deficiency is also identified as the cause of severe haemolysis following administration of the anti-malarial drug primaquine and further use of this drug will likely require identification of G6PD deficiency on a population level. Current conventional methods for G6PD screening have various disadvantages for field use. Methods The WST8/1-methoxy PMS method, recently adapted for field use, was validated using a gold standard enzymatic assay (R&D Diagnostics Ltd ®) in a study involving 235 children under five years of age, who were recruited by random selection from a cohort study in Tororo, Uganda. Blood spots were collected by finger-prick onto filter paper at routine visits, and G6PD activity was determined by both tests. Performance of the WST8/1-methoxy PMS test under various temperature, light, and storage conditions was evaluated. Results The WST8/1-methoxy PMS assay was found to have 72% sensitivity and 98% specificity when compared to the commercial enzymatic assay and the AUC was 0.904, suggesting good agreement. Misclassifications were at borderline values of G6PD activity between mild and normal levels, or related to outlier haemoglobin values (<8.0 gHb/dl or >14 gHb/dl) associated with ongoing anaemia or recent haemolytic crises. Although severe G6PD deficiency was not found in the area, the test enabled identification of low G6PD activity. The assay was found to be highly robust for field use; showing less light sensitivity, good performance over a wide temperature range, and good capacity for medium-to-long term storage. Conclusions The WST8/1-methoxy PMS assay was comparable to the currently used standard enzymatic test, and offers advantages in terms of cost, storage, portability and use in resource-limited settings. Such features make this test a potential key tool for deployment in the field for point of care assessment prior to primaquine administration in malaria-endemic areas. As with other G6PD tests, outlier haemoglobin levels may confound G6PD level estimation. PMID:23782846

Tools for mass screening of G6PD deficiency: validation of the WST8/1-methoxy-PMS enzymatic assay in Uganda.

PubMed

De Niz, Mariana; Eziefula, Alice C; Othieno, Lucas; Mbabazi, Edith; Nabukeera, Damalie; Ssemmondo, Emmanuel; Gonahasa, Samuel; Tumwebaze, Patrick; Diliberto, Deborah; Maiteki-Sebuguzi, Catherine; Staedke, Sarah G; Drakeley, Chris

2013-06-19

The distribution of the enzymopathy glucose-6-phosphate dehydrogenase (G6PD) deficiency is linked to areas of high malaria endemicity due to its association with protection from disease. G6PD deficiency is also identified as the cause of severe haemolysis following administration of the anti-malarial drug primaquine and further use of this drug will likely require identification of G6PD deficiency on a population level. Current conventional methods for G6PD screening have various disadvantages for field use. The WST8/1-methoxy PMS method, recently adapted for field use, was validated using a gold standard enzymatic assay (R&D Diagnostics Ltd ®) in a study involving 235 children under five years of age, who were recruited by random selection from a cohort study in Tororo, Uganda. Blood spots were collected by finger-prick onto filter paper at routine visits, and G6PD activity was determined by both tests. Performance of the WST8/1-methoxy PMS test under various temperature, light, and storage conditions was evaluated. The WST8/1-methoxy PMS assay was found to have 72% sensitivity and 98% specificity when compared to the commercial enzymatic assay and the AUC was 0.904, suggesting good agreement. Misclassifications were at borderline values of G6PD activity between mild and normal levels, or related to outlier haemoglobin values (<8.0 gHb/dl or >14 gHb/dl) associated with ongoing anaemia or recent haemolytic crises. Although severe G6PD deficiency was not found in the area, the test enabled identification of low G6PD activity. The assay was found to be highly robust for field use; showing less light sensitivity, good performance over a wide temperature range, and good capacity for medium-to-long term storage. The WST8/1-methoxy PMS assay was comparable to the currently used standard enzymatic test, and offers advantages in terms of cost, storage, portability and use in resource-limited settings. Such features make this test a potential key tool for deployment in the field for point of care assessment prior to primaquine administration in malaria-endemic areas. As with other G6PD tests, outlier haemoglobin levels may confound G6PD level estimation.

Novel urea and bis-urea primaquine derivatives with hydroxyphenyl or halogenphenyl substituents: Synthesis and biological evaluation.

PubMed

Perković, I; Antunović, M; Marijanović, I; Pavić, K; Ester, K; Kralj, M; Vlainić, J; Kosalec, I; Schols, D; Hadjipavlou-Litina, D; Pontiki, E; Zorc, B

2016-11-29

A series of novel compounds 3a-j and 6a-j with primaquine and hydroxyl or halogen substituted benzene moieties bridged by urea or bis-urea functionalities were designed, synthesized and evaluated for biological activity. The title compounds were prepared using benzotriazole as the synthon, through several synthetic steps. 3-[3,5-Bis(trifluoromethyl)phenyl]-1-{4-[(6-methoxyquinolin-8-yl)amino]pentyl}urea (3j) was the most active urea and 1-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]-3-[3-(trifluoromethyl)phenyl]urea (6h) the most active bis-urea derivative in antiproliferative screening in vitro against eight tested cancer cell lines. Urea derivatives 3a-g with hydroxy group or one halogen atom showed moderate antiproliferative effects against all the tested cell lines, but stronger activity against breast carcinoma MCF-7 cell line, while trifluoromethyl derivatives 3h-j showed antiproliferative effects against all the tested cell lines in low micromolar range. Finally, bis-ureas with hydroxy and fluoro substituents 6a-d showed extreme selectivity and chloro or bromo derivatives 6e-g high selectivity against MCF-7 cells (IC 50 0.1-2.6 μM). p-Fluoro derivative 6d, namely 3-(4-fluorophenyl)-1-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]urea, is the most promising compound. Further biological experiments showed that 6d affected cell cycle and induced cell death of MCF-7 cell line. Due to its high activity against MCF-7 cell line (IC 50 0.31 μM), extreme selectivity and full agreement with the Lipinski's and Gelovani's rules for prospective small molecular drugs, 6d may be considered as a lead compound in development of breast carcinoma drugs. Urea 3b and almost all bis-ureas showed high antioxidant activity in DPPH assay, but urea derivatives were more active in lipid peroxidation test. Only few compounds exhibited weak inhibition of soybean lipoxygenase. Compound 3j exhibited the strongest antimicrobial activity in susceptibility assay in vitro (MIC = 1.6-12.5 μg ml -1 ). Copyright © 2016 Elsevier Masson SAS. All rights reserved.

The role of early detection and treatment in malaria elimination.

PubMed

Landier, Jordi; Parker, Daniel M; Thu, Aung Myint; Carrara, Verena I; Lwin, Khin Maung; Bonnington, Craig A; Pukrittayakamee, Sasithon; Delmas, Gilles; Nosten, François H

2016-07-15

Falciparum malaria persists in hard-to-reach areas or demographic groups that are missed by conventional healthcare systems but could be reached by trained community members in a malaria post (MP). The main focus of a MP is to provide uninterrupted and rapid access to rapid diagnostic tests (RDTs) and artemisinin-based combination therapy (ACT) too all inhabitants of a village. RDTs allow trained community members to perform malaria diagnosis accurately and prescribe appropriate treatment, reducing as much as possible any delay between the onset of fever and treatment. Early treatment with ACT and with a low-dose of primaquine prevents further transmission from human to mosquito. A functioning MP represents an essential component of any malaria elimination strategy. Implementing large-scale, high-coverage, community-based early diagnosis and treatment through MPs requires few technological innovations but relies on a very well structured organization able to train, supervise and supply MPs, to monitor activity and to perform strict malaria surveillance.

A screen of pharmaceutical drugs for their ability to cause short-term morbidity and mortality in the common bed bug, Cimex lectularius L.

PubMed

Sheele, Johnathan M; Ridge, Gale E; Du, Wenjing; Mallipeddi, Nikhil; Vallabhaneni, Mayur

2017-10-01

The common bed bug, Cimex lectularius L., is a hematophagous ectoparasite that preferentially feeds on humans. Pharmaceuticals present in a person's blood may adversely affect C. lectularius when it feeds. We fed >10,000 C. lectularius on blood samples containing more than 400 different drug doses and drug combinations using an in vitro feeding system to determine insect mortality. The majority of drug doses approximated the peak plasma concentration in humans taking those drugs. Twenty-one drugs were found to cause >17% 12-14-day mortality compared to 8.5% mortality in the control (p < 0.05), but postliminary testing of three of the drugs, famotidine, ethambutol, and primaquine, did not demonstrate an increase in C. lectularius mortality. We also tested 23 drugs for their effects on C. lectularius fecundity. The results may have implications for understanding C. lectularius population dynamics in an infestation.

Global Epidemiology of Plasmodium vivax

PubMed Central

Howes, Rosalind E.; Battle, Katherine E.; Mendis, Kamini N.; Smith, David L.; Cibulskis, Richard E.; Baird, J. Kevin; Hay, Simon I.

2016-01-01

Plasmodium vivax is the most widespread human malaria, putting 2.5 billion people at risk of infection. Its unique biological and epidemiological characteristics pose challenges to control strategies that have been principally targeted against Plasmodium falciparum. Unlike P. falciparum, P. vivax infections have typically low blood-stage parasitemia with gametocytes emerging before illness manifests, and dormant liver stages causing relapses. These traits affect both its geographic distribution and transmission patterns. Asymptomatic infections, high-risk groups, and resulting case burdens are described in this review. Despite relatively low prevalence measurements and parasitemia levels, along with high proportions of asymptomatic cases, this parasite is not benign. Plasmodium vivax can be associated with severe and even fatal illness. Spreading resistance to chloroquine against the acute attack, and the operational inadequacy of primaquine against the multiple attacks of relapse, exacerbates the risk of poor outcomes among the tens of millions suffering from infection each year. Without strategies accounting for these P. vivax-specific characteristics, progress toward elimination of endemic malaria transmission will be substantially impeded. PMID:27402513

Antimalarial activity of novel 5-aryl-8-aminoquinoline derivatives.

PubMed

Shiraki, Hiroaki; Kozar, Michael P; Melendez, Victor; Hudson, Thomas H; Ohrt, Colin; Magill, Alan J; Lin, Ai J

2011-01-13

In an attempt to separate the antimalarial activity of tafenoquine (3) from its hemolytic side effects in glucose-6-phosphate dehydrogenase (G6PD) deficiency patients, a series of 5-aryl-8-aminoquinoline derivatives was prepared and assessed for antimalarial activities. The new compounds were found metabolically stable in human and mouse microsomal preparations, with t(1/2) > 60 min, and were equal to or more potent than primaquine (2) and 3 against Plasmodium falciparum cell growth. The new agents were more active against the chloroquine (CQ) resistant clone than to the CQ-sensitive clone. Analogues with electron donating groups showed better activity than those with electron withdrawing substituents. Compounds 4bc, 4bd, and 4be showed comparable therapeutic index (TI) to that of 2 and 3, with TI ranging from 5 to 8 based on IC(50) data. The new compounds showed no significant causal prophylactic activity in mice infected with Plasmodium berghei sporozoites, but are substantially less toxic than 2 and 3 in mouse tests.

Blocking Plasmodium falciparum Malaria Transmission with Drugs: The Gametocytocidal and Sporontocidal Properties of Current and Prospective Antimalarials

PubMed Central

Kiszewski, Anthony E.

2011-01-01

Drugs that kill or inhibit the sexual stages of Plasmodium could potentially amplify or synergize the impact of other interventions by blocking transmission to mosquitoes. Primaquine and other 8-aminoquinolines have long offered such potential, but safety and other concerns have limited their use. Although transmission-blocking properties are not often a priority of drug discovery efforts, a number of interesting gametocytocidal and/or sporontocidal drug candidates have emerged in recent years. Some still bear significant technical and safety concerns, while others have passed clinical trials and are on the verge of entering the antimalarial armamentarium. Recent advances in our knowledge of gametocyte differentiation, gametogenesis and sporogony have also led to the identification of a large array of potential new targets for drugs that might interfere with malaria transmission. This review examines the properties of existing and prospective drugs, mechanisms of action, counter-indications and their potential role in regional malaria elimination efforts.

Plasmodium vivax liver stage development and hypnozoite persistence in human liver-chimeric mice

PubMed Central

Mikolajczak, Sebastian A.; Vaughan, Ashley M.; Kangwanrangsan, Niwat; Roobsoong, Wanlapa; Fishbaugher, Matthew; Yimamnuaychok, Narathatai; Rezakhani, Nastaran; Lakshmanan, Viswanathan; Singh, Naresh; Kaushansky, Alexis; Camargo, Nelly; Baldwin, Michael; Lindner, Scott E.; Adams, John H.; Prachumsri, Jetsumon; Kappe, Stefan H.I.

2017-01-01

Plasmodium vivax malaria is characterized by periodic relapses of symptomatic blood stage parasite infections likely initiated by activation of dormant liver stage parasites -hypnozoites. The lack of tractable animal models for P. vivax constitutes a severe obstacle to investigate this unique aspect of its biology and to test drug efficacy against liver stages. We show that the FRG KO huHep liver-humanized mice support P. vivax sporozoite infection, development of liver stages, and the formation of small non-replicating hypnozoites. Cellular characterization of P. vivax liver stage development in vivo demonstrates complete maturation into infectious exo-erythrocytic merozoites and continuing persistence of hypnozoites. Primaquine prophylaxis or treatment prevents and eliminates liver stage infection. Thus, the P. vivax/FRG KO huHep mouse infection model constitutes an important new tool to investigate the biology of liver stage development and dormancy and might aid in the discovery of new drugs for the prevention of relapsing malaria. PMID:25800544

CLINICAL EFFECT OF HEMOPARASITE INFECTIONS IN SNOWY OWLS ( BUBO SCANDIACUS).

PubMed

Baker, Kendra C; Rettenmund, Christy L; Sander, Samantha J; Rivas, Anne E; Green, Kaitlin C; Mangus, Lisa; Bronson, Ellen

2018-03-01

Vector-borne hemoparasites are commonly found in avian species. Plasmodium spp., the causative agent of avian malaria, are intraerythrocytic parasites that can cause signs ranging from subclinical infection to severe acute disease. In raptor species, most hemoparasites are associated with subclinical infection and are generally not treated when seen on blood evaluation. This case series reviews five cases of hemoparasite infection in snowy owls ( Bubo scandiacus). These animals were infected with a variety of hemoparasites, including Plasmodium, Haemoproteus, and Leukocytozoon spp. Death of one of these birds due to hemoparasite burden led to a change in the monitoring for and treatment of subclinical hemoparasitic infections in this species. Three subsequently infected snowy owls have been treated with primaquine and chloroquine. The birds that were treated survived infection, and parasite burdens in peripheral blood diminished. Postulated reasons for increased morbidity and mortality associated with hemoparasitic infections in captive snowy owls, as opposed to other raptor species, include stress, concurrent disease, novel pathogen exposure, and elevated environmental temperatures.

Safety of single low-dose primaquine in glucose-6-phosphate dehydrogenase deficient falciparum-infected African males: Two open-label, randomized, safety trials.

PubMed

Bastiaens, Guido J H; Tiono, Alfred B; Okebe, Joseph; Pett, Helmi E; Coulibaly, Sam A; Gonçalves, Bronner P; Affara, Muna; Ouédraogo, Alphonse; Bougouma, Edith C; Sanou, Guillaume S; Nébié, Issa; Bradley, John; Lanke, Kjerstin H W; Niemi, Mikko; Sirima, Sodiomon B; d'Alessandro, Umberto; Bousema, Teun; Drakeley, Chris

2018-01-01

Primaquine (PQ) actively clears mature Plasmodium falciparum gametocytes but in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals can cause hemolysis. We assessed the safety of low-dose PQ in combination with artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) in G6PDd African males with asymptomatic P. falciparum malaria. In Burkina Faso, G6PDd adult males were randomized to treatment with AL alone (n = 10) or with PQ at 0.25 (n = 20) or 0.40 mg/kg (n = 20) dosage; G6PD-normal males received AL plus 0.25 (n = 10) or 0.40 mg/kg (n = 10) PQ. In The Gambia, G6PDd adult males and boys received DP alone (n = 10) or with 0.25 mg/kg PQ (n = 20); G6PD-normal males received DP plus 0.25 (n = 10) or 0.40 mg/kg (n = 10) PQ. The primary study endpoint was change in hemoglobin concentration during the 28-day follow-up. Cytochrome P-450 isoenzyme 2D6 (CYP2D6) metabolizer status, gametocyte carriage, haptoglobin, lactate dehydrogenase levels and reticulocyte counts were also determined. In Burkina Faso, the mean maximum absolute change in hemoglobin was -2.13 g/dL (95% confidence interval [CI], -2.78, -1.49) in G6PDd individuals randomized to 0.25 PQ mg/kg and -2.29 g/dL (95% CI, -2.79, -1.79) in those receiving 0.40 PQ mg/kg. In The Gambia, the mean maximum absolute change in hemoglobin concentration was -1.83 g/dL (95% CI, -2.19, -1.47) in G6PDd individuals receiving 0.25 PQ mg/kg. After adjustment for baseline concentrations, hemoglobin reductions in G6PDd individuals in Burkina Faso were more pronounced compared to those in G6PD-normal individuals receiving the same PQ doses (P = 0.062 and P = 0.022, respectively). Hemoglobin levels normalized during follow-up. Abnormal haptoglobin and lactate dehydrogenase levels provided additional evidence of mild transient hemolysis post-PQ. Single low-dose PQ in combination with AL and DP was associated with mild and transient reductions in hemoglobin. None of the study participants developed moderate or severe anemia; there were no severe adverse events. This indicates that single low-dose PQ is safe in G6PDd African males when used with artemisinin-based combination therapy. Clinicaltrials.gov NCT02174900 Clinicaltrials.gov NCT02654730.

Safety of primaquine given to people with G6PD deficiency: systematic review of prospective studies.

PubMed

Uthman, Olalekan A; Graves, Patricia M; Saunders, Rachel; Gelband, Hellen; Richardson, Marty; Garner, Paul

2017-08-22

Haemolysis risk with single dose or short course primaquine was evaluated in glucose-6-phosphate dehydrogenase (G6PD) deficient people. Major electronic databases (to August 2016) were searched for single or short course 8-aminoquinolines (8-AQ) in (1) randomized comparisons against placebo in G6PD deficient people; and (2) observational comparisons in G6PD deficient compared to replete people. Two authors independently assessed eligibility, risk-of-bias, and extracted data. Five randomized controlled trials and four controlled observational cohorts were included. In G6PD deficient individuals, high-dose (0.75 mg/kg) PQ resulted in lower average haemoglobin levels at 7 days (mean difference [MD] -1.45 g/dl, 95% CI -2.17 to -0.74, 2 trials) and larger percentage fall from baseline to day 7 (MD -10.31%, 95% CI -17.69 to -2.92, 3 trials) compared to placebo. In G6PD deficient compared to replete people, average haemoglobin was lower at 7 days (MD -1.19 g/dl, 95% CI -1.94 to -0.44, 2 trials) and haemoglobin change from baseline to day 7 was greater (MD -9.10%, 95% CI -12.55 to -5.65, 5 trials). One small trial evaluated mid-range PQ dose (0.4-0.5 mg/kg) in G6PD deficient people, with no difference detected in average haemoglobin at day 7 compared to placebo. In one cohort comparing G6PD deficient and replete people there was a greater fall with G6PD deficiency (MD -4.99%, 95% CI -9.96 to -0.02). For low-dose PQ (0.1-0.25 mg/kg) in G6PD deficient people, haemoglobin change from baseline was similar to the placebo group (MD 1.72%, 95% CI -1.89 to 5.34, 2 trials). Comparing low dose PQ in G6PD deficient with replete people, the average haemoglobin was lower in the G6PD deficient group at 7 days (-0.57 g (95% CI -0.97 to -0.17, 1 trial)); although change from baseline was similar (MD -1.45%, 95% CI -5.69 to 2.78, 3 trials). Falls in average haemoglobin are less marked with the 0.1 to 0.25 mg/kg PQ than with the 0.75 mg/kg dose, and severe haemolytic events are not common. However, data were limited and the evidence GRADE was low or very low certainty.

Safety of single low-dose primaquine in glucose-6-phosphate dehydrogenase deficient falciparum-infected African males: Two open-label, randomized, safety trials

PubMed Central

Pett, Helmi E.; Coulibaly, Sam A.; Gonçalves, Bronner P.; Affara, Muna; Ouédraogo, Alphonse; Bougouma, Edith C.; Sanou, Guillaume S.; Nébié, Issa; Bradley, John; Lanke, Kjerstin H. W.; Niemi, Mikko; Sirima, Sodiomon B.; d’Alessandro, Umberto; Bousema, Teun; Drakeley, Chris

2018-01-01

Background Primaquine (PQ) actively clears mature Plasmodium falciparum gametocytes but in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals can cause hemolysis. We assessed the safety of low-dose PQ in combination with artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) in G6PDd African males with asymptomatic P. falciparum malaria. Methods and findings In Burkina Faso, G6PDd adult males were randomized to treatment with AL alone (n = 10) or with PQ at 0.25 (n = 20) or 0.40 mg/kg (n = 20) dosage; G6PD-normal males received AL plus 0.25 (n = 10) or 0.40 mg/kg (n = 10) PQ. In The Gambia, G6PDd adult males and boys received DP alone (n = 10) or with 0.25 mg/kg PQ (n = 20); G6PD-normal males received DP plus 0.25 (n = 10) or 0.40 mg/kg (n = 10) PQ. The primary study endpoint was change in hemoglobin concentration during the 28-day follow-up. Cytochrome P-450 isoenzyme 2D6 (CYP2D6) metabolizer status, gametocyte carriage, haptoglobin, lactate dehydrogenase levels and reticulocyte counts were also determined. In Burkina Faso, the mean maximum absolute change in hemoglobin was -2.13 g/dL (95% confidence interval [CI], -2.78, -1.49) in G6PDd individuals randomized to 0.25 PQ mg/kg and -2.29 g/dL (95% CI, -2.79, -1.79) in those receiving 0.40 PQ mg/kg. In The Gambia, the mean maximum absolute change in hemoglobin concentration was -1.83 g/dL (95% CI, -2.19, -1.47) in G6PDd individuals receiving 0.25 PQ mg/kg. After adjustment for baseline concentrations, hemoglobin reductions in G6PDd individuals in Burkina Faso were more pronounced compared to those in G6PD-normal individuals receiving the same PQ doses (P = 0.062 and P = 0.022, respectively). Hemoglobin levels normalized during follow-up. Abnormal haptoglobin and lactate dehydrogenase levels provided additional evidence of mild transient hemolysis post-PQ. Conclusions Single low-dose PQ in combination with AL and DP was associated with mild and transient reductions in hemoglobin. None of the study participants developed moderate or severe anemia; there were no severe adverse events. This indicates that single low-dose PQ is safe in G6PDd African males when used with artemisinin-based combination therapy. Trial registration Clinicaltrials.gov NCT02174900 Clinicaltrials.gov NCT02654730 PMID:29324864

Safety of a single low-dose of primaquine in addition to standard artemether-lumefantrine regimen for treatment of acute uncomplicated Plasmodium falciparum malaria in Tanzania.

PubMed

Mwaiswelo, Richard; Ngasala, Billy E; Jovel, Irina; Gosling, Roland; Premji, Zul; Poirot, Eugenie; Mmbando, Bruno P; Björkman, Anders; Mårtensson, Andreas

2016-06-10

This study assessed the safety of the new World Health Organization (WHO) recommendation of adding a single low-dose of primaquine (PQ) to standard artemisinin-based combination therapy (ACT), regardless of individual glucose-6-phosphate dehydrogenase (G6PD) status, for treatment of acute uncomplicated Plasmodium falciparum malaria in Tanzania. Men and non-pregnant, non-lactating women aged ≥1 year with uncomplicated P. falciparum malaria were enrolled and randomized to either standard artemether-lumefantrine (AL) regimen alone or with a 0.25 mg/kg single-dose of PQ. PQ was administered concomitantly with the first AL dose. All drug doses were supervised. Safety was evaluated between days 0 and 28. G6PD status was assessed using rapid test (CareStart™) and molecular genotyping. The primary endpoint was mean percentage relative reduction in haemoglobin (Hb) concentration (g/dL) between days 0 and 7 by genotypic G6PD status and treatment arm. Overall, 220 patients, 110 per treatment arm, were enrolled, of whom 33/217 (15.2 %) were phenotypically G6PD deficient, whereas 15/110 (13.6 %) were genotypically hemizygous males, 5/110 (4.5 %) homozygous females and 22/110 (20 %) heterozygous females. Compared to genotypically G6PD wild-type/normal [6.8, 95 % confidence interval (CI) 4.67-8.96], only heterozygous patients in AL arm had significant reduction in day-7 mean relative Hb concentration (14.3, 95 % CI 7.02-21.55, p=0.045), however, none fulfilled the pre-defined haemolytic threshold value of ≥25 % Hb reduction. After adjustment for baseline parasitaemia, Hb, age and sex the mean relative Hb reduction was not statistically significant in both heterozygous and hemizygous/homozygous patients in both arms. A majority of the adverse events (AEs) were mild and unrelated to the study drugs. However, six (4.4 %) episodes, three per treatment arm, of acute haemolytic anaemia occurred between days 0 and 7. Three occurred in phenotypically G6PD deficient patients, two in AL and one in AL + PQ arm, but none in genotypically hemizygous/homozygous patients. All patients with acute haemolytic anaemia recovered without medical intervention. The findings support that the WHO recommendation of adding a single low-dose of PQ to standard AL regimen is safe for the treatment of acute uncomplicated P. falciparum malaria regardless of G6PD status in Tanzania. Trial registration number NCT02090036.

Safety, efficacy and pharmacokinetic evaluations of a new coated chloroquine tablet in a single-arm open-label non-comparative trial in Brazil: a step towards a user-friendly malaria vivax treatment.

PubMed

Pereira, Dhelio; Daher, André; Zanini, Graziela; Maia, Ivan; Fonseca, Lais; Pitta, Luciana; Ruffato, Rosilene; Marchesini, Paola; Fontes, Cor Jesus

2016-09-17

Malaria remains a major public health problem, with half the world population at risk of contracting malaria. The effects of Plasmodium vivax on prosperity and longevity have been highlighted in several recent clinical case reports. The first line of vivax treatment drugs has seen no radical innovation for more than 60 years. This study introduces a subtle incremental innovation to vivax treatment: a chloroquine and primaquine co-blister. The co-blister includes a new chloroquine formulation incorporating coated tablets to mask the drug's bitter taste and user-friendly packaging containing tablets of each drug, which may improve patient adherence and facilitate the appropriate use of the drugs. This new formulation will replace the non-coated chloroquine distributed in Brazil. Patients were orally treated with 150 mg coated chloroquine tablets for 3 days: an initial 450 mg dose, followed by two 300 mg doses. The patients were treated concomitantly with two 15 mg primaquine tablets for 7-9 days, according to their weight. The primary objective of this study was to prove parasitological and clinical cure rates above 90 % by day 28. This single-arm open-label non-comparative trial was conducted according to the WHO recommended methodology for the surveillance of anti-malarial drug efficacy in the Brazilian Amazon. On day 28, the parasitological and clinical response was adequate in 98.8 % of patients (CI 95 % 93.4-100 %). The success rate on day 3 was 100 %, and the cumulative success rate by day 28 was 98.8 % (CI 95 % 91.7-99.8 %). There were no serious adverse events, with most adverse events classified as mild. The pharmacokinetic parameters of chloroquine analysed in whole blood dry spot samples showed mean (coefficient of variation) Cmax and AUC0-t values of 374.44 (0.35) and 3700.43 (0.36) ng/mL, respectively. This study reports an appropriate safety and efficacy profile of a new formulation of coated chloroquine tablets for vivax malaria treatment in the Brazilian Amazon. The cure rates meet the WHO efficacy criteria, supporting current Brazilian guidelines and the use of the formulation for vivax malaria treatment. Nevertheless, further studies should be conducted to address adherence and the effectiveness of the formulation. Trial registration RBR-77q7t3-UTN: U1111-1121-2982. Registered 10th May 2011.

Prevalence and distribution of glucose-6-phosphate dehydrogenase (G6PD) variants in Thai and Burmese populations in malaria endemic areas of Thailand.

PubMed

Phompradit, Papichaya; Kuesap, Jiraporn; Chaijaroenkul, Wanna; Rueangweerayut, Ronnatrai; Hongkaew, Yaowaluck; Yamnuan, Rujira; Na-Bangchang, Kesara

2011-12-15

G6PD deficiency is common in malaria endemic regions and is estimated to affect more than 400 million people worldwide. Treatment of malaria patients with the anti-malarial drug primaquine or other 8-aminoquinolines may be associated with potential haemolytic anaemia. The aim of the present study was to investigate the prevalence of G6PD variants in Thai population who resided in malaria endemic areas (western, northern, north-eastern, southern, eastern and central regions) of Thailand, as well as the Burmese population who resided in areas along the Thai-Myanmar border. The ten common G6PD variants were investigated in dried blood spot samples collected from 317 Thai (84 males, 233 females) and 183 Burmese (11 males, 172 females) populations residing in malaria endemic areas of Thailand using PCR-RFLP method. Four and seven G6PD variants were observed in samples collected from Burmese and Thai population, with prevalence of 6.6% (21/317) and 14.2% (26/183), respectively. Almost all (96.2%) of G6PD mutation samples collected from Burmese population carried G6PD Mahidol variant; only one sample (3.8%) carried G6PD Kaiping variant. For the Thai population, G6PD Mahidol (8/21: 38.1%) was the most common variant detected, followed by G6PD Viangchan (4/21: 19.0%), G6PD Chinese 4 (3/21: 14.3%), G6PD Canton (2/21: 9.5%), G6PD Union (2/21: 9.5%), G6PD Kaiping (1/21: 4.8%), and G6PD Gaohe (1/21: 4.8%). No G6PD Chinese 3, Chinese 5 and Coimbra variants were found. With this limited sample size, there appeared to be variation in G6PD mutation variants in samples obtained from Thai population in different regions particularly in the western region. Results indicate difference in the prevalence and distribution of G6PD gene variants among the Thai and Burmese populations in different malaria endemic areas. Dosage regimen of primaquine for treatment of both Plasmodium falciparum and Plasmodium vivax malaria may need to be optimized, based on endemic areas with supporting data on G6PD variants. Larger sample size from different malaria endemic is required to obtain accurate genetic mapping of G6PD variants in Burmese and Thai population residing in malaria endemic areas of Thailand.

Prevalence and distribution of glucose-6-phosphate dehydrogenase (G6PD) variants in Thai and Burmese populations in malaria endemic areas of Thailand

PubMed Central

2011-01-01

Background G6PD deficiency is common in malaria endemic regions and is estimated to affect more than 400 million people worldwide. Treatment of malaria patients with the anti-malarial drug primaquine or other 8-aminoquinolines may be associated with potential haemolytic anaemia. The aim of the present study was to investigate the prevalence of G6PD variants in Thai population who resided in malaria endemic areas (western, northern, north-eastern, southern, eastern and central regions) of Thailand, as well as the Burmese population who resided in areas along the Thai-Myanmar border. Methods The ten common G6PD variants were investigated in dried blood spot samples collected from 317 Thai (84 males, 233 females) and 183 Burmese (11 males, 172 females) populations residing in malaria endemic areas of Thailand using PCR-RFLP method. Results Four and seven G6PD variants were observed in samples collected from Burmese and Thai population, with prevalence of 6.6% (21/317) and 14.2% (26/183), respectively. Almost all (96.2%) of G6PD mutation samples collected from Burmese population carried G6PD Mahidol variant; only one sample (3.8%) carried G6PD Kaiping variant. For the Thai population, G6PD Mahidol (8/21: 38.1%) was the most common variant detected, followed by G6PD Viangchan (4/21: 19.0%), G6PD Chinese 4 (3/21: 14.3%), G6PD Canton (2/21: 9.5%), G6PD Union (2/21: 9.5%), G6PD Kaiping (1/21: 4.8%), and G6PD Gaohe (1/21: 4.8%). No G6PD Chinese 3, Chinese 5 and Coimbra variants were found. With this limited sample size, there appeared to be variation in G6PD mutation variants in samples obtained from Thai population in different regions particularly in the western region. Conclusions Results indicate difference in the prevalence and distribution of G6PD gene variants among the Thai and Burmese populations in different malaria endemic areas. Dosage regimen of primaquine for treatment of both Plasmodium falciparum and Plasmodium vivax malaria may need to be optimized, based on endemic areas with supporting data on G6PD variants. Larger sample size from different malaria endemic is required to obtain accurate genetic mapping of G6PD variants in Burmese and Thai population residing in malaria endemic areas of Thailand. PMID:22171972

Therapeutic Responses to Different Antimalarial Drugs in Vivax Malaria

PubMed Central

Pukrittayakamee, Sasithon; Chantra, Arun; Simpson, Julie A.; Vanijanonta, Sirivan; Clemens, Ralf; Looareesuwan, Sornchai; White, Nicholas J.

2000-01-01

The therapeutic responses to the eight most widely used antimalarial drugs were assessed in 207 adult patients with Plasmodium vivax malaria. This parasite does not cause marked sequestration, so parasite clearance can be used as a direct measure of antimalarial activity. The activities of these drugs in descending order were artesunate, artemether, chloroquine, mefloquine, quinine, halofantrine, primaquine, and pyrimethamine-sulfadoxine (PS). Therapeutic responses to PS were poor; parasitemias did not clear in 5 of the 12 PS-treated patients, whereas all the other patients made an initial recovery. Of 166 patients monitored for ≥28 days, 35% had reappearance of vivax malaria 11 to 65 days later and 7% developed falciparum malaria 5 to 21 days after the start of treatment. There were no significant differences in the times taken for vivax malaria reappearance among the different groups except for those given mefloquine and chloroquine, in which all vivax malaria reappearances developed >28 days after treatment, suggesting suppression of the first relapse by these slowly eliminated drugs. There was no evidence of chloroquine resistance. The antimalarial drugs vary considerably in their intrinsic activities and stage specificities of action. PMID:10817728

A successful therapy for severe malaria accompanied by malaria-related acute kidney injury (MAKI) complications: a case report

NASA Astrophysics Data System (ADS)

Syahputra, A.; Siregar, M. L.; Jamil, K. F.

2018-03-01

Indonesia is an endemic malaria country with high levels of morbidity and mortality. In Aceh, by the end of 2016, based on the data from Annual Parasite Incidence, the incidence rate was 0.1 per 1.000 population at risk of malaria. One of severe malaria complications is malaria-related acute kidney injury(MAKI). The death increasesthreefold by the presence of MAKI. A 56 years old male farmer was a resident in Buketmeuh village, Meukek, South Aceh, Indonesia, which was an endemic malaria area. He hadfever for seven days, chills, sweating, joint pain, headache, nausea, vomit, yellow eyes and raved. Concentrated tea-colored urineduring four days before hospital admission with a small amount of urine of 200 cc in 24 hours. The diagnosis established based on the Plasmodium vivax trophozoite finding in the blood smear examination, and the severe malaria clinical descriptions such as black water fever (BWF)with MAKI complications. Artemether injection therapy followed by oral primaquine, dihydroartemisinin and piperaquine phosphate (DHP) and hemodialysis provide a good outcome.

Using genetic methods to define the targets of compounds with antimalarial activity

PubMed Central

Flannery, Erika L.; Fidock, David A.; Winzeler, Elizabeth A.

2013-01-01

Although phenotypic cellular screening has been used to drive antimalarial drug discovery in recent years, in some cases target-based drug discovery remains more attractive. This is especially true when appropriate high-throughput cellular assays are lacking, as is the case for drug discovery efforts that aim to provide a replacement for primaquine (4-N-(6-methoxyquinolin-8-yl)pentane-1,4-diamine), the only drug that can block Plasmodium transmission to Anopheles mosquitoes and eliminate liver-stage hypnozoites. At present, however, there are no known chemically validated parasite protein targets that are important in all Plasmodium parasite developmental stages and that can be used in traditional biochemical compound screens. We propose that a plethora of novel, chemically validated, cross-stage antimalarial targets still remain to be discovered from the ~5,500 proteins encoded by the Plasmodium genomes. Here we discuss how in vitro evolution of drug-resistant strains of Plasmodium falciparum and subsequent whole-genome analysis can be used to find the targets of some of the many compounds discovered in whole-cell phenotypic screens. PMID:23927658

Antimalarial drug policy in India: past, present & future.

PubMed

Anvikar, Anupkumar R; Arora, Usha; Sonal, G S; Mishra, Neelima; Shahi, Bharatendu; Savargaonkar, Deepali; Kumar, Navin; Shah, Naman K; Valecha, Neena

2014-02-01

The use of antimalarial drugs in India has evolved since the introduction of quinine in the 17 th century. Since the formal establishment of a malaria control programme in 1953, shortly after independence, treatments provided by the public sector ranged from chloroquine, the mainstay drug for many decades, to the newer, recently introduced artemisinin based combination therapy. The complexity of considerations in antimalarial treatment led to the formulation of a National Antimalarial Drug Policy to guide procurement as well as communicate best practices to both public and private healthcare providers. Challenges addressed in the policy include the use of presumptive treatment, the introduction of alternate treatments for drug-resistant malaria, the duration of primaquine therapy to prevent relapses of vivax malaria, the treatment of malaria in pregnancy, and the choice of drugs for chemoprophylaxis. While data on antimalarial drug resistance and both public and private sector treatment practices have been recently reviewed, the policy process of setting national standards has not. In this perspective on antimalarial drug policy, this review highlights its relevant history, analyzes the current policy, and examines future directions.

Performance of the CareStart Glucose-6-Phosphate Dehydrogenase (G6PD) Rapid Diagnostic Test in Gressier, Haiti

PubMed Central

von Fricken, Michael E.; Weppelmann, Thomas A.; Eaton, Will T.; Masse, Roseline; Beau de Rochars, Madsen V. E.; Okech, Bernard A.

2014-01-01

Administering primaquine (PQ) to treat malaria patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency can pose a serious risk of drug-induced hemolysis (DIH). New easy to use point-of-care rapid diagnostic tests are being developed as an alternative to labor-intensive spectrophotometric methods, but they require field testing before they can be used at scale. This study screened 456 participants in Gressier, Haiti using the Access Bio CareStart qualitative G6PD rapid detection test compared with the laboratory-based Trinity Biotech quantitative spectrophotometric assay. Findings suggest that the CareStart test was 90% sensitive for detecting individuals with severe deficiency and 84.8% sensitive for detecting individuals with moderate and severe deficiency compared with the Trinity Biotech assay. A high negative predictive value of 98.2% indicates excellent performance in determining those patients able to take PQ safely. The CareStart G6PD test holds much value for screening malaria patients to determine eligibility for PQ therapy. PMID:24778197

Antimalarial activities of new guanidylimidazole and guanidylimidazoline derivatives.

PubMed

Zhang, Liang; Sathunuru, Ramadas; Caridha, Diana; Pybus, Brandon; O'Neil, Michael T; Kozar, Michael P; Lin, Ai J

2011-10-13

A series of new guanidylimidazole derivatives was prepared and evaluated in mice and Rhesus monkeys infected with malarial sporozoites. The majority of the new compounds showed poor metabolic stability and weak in vitro activities in three clones of Plasmodium falciparum. Compounds 8a, 8h, 9a, 16a, and 16e cured the mice infected with sporozoites of P. berghei at 160 and 320 mg/kg/day × 3 po. Compounds 8a showed better causal prophylactic activity than primaquine, tafenoquine, and Malarone in the Rhesus test. In the radical curative test, 8a cured one monkey and delayed relapse of another for 74 days at 30 mg/kg/day × 7 by im. By oral dosing, 8a delayed relapse 81 days for one and 32 days for other vs 11-12 days for control monkeys treated with 10 mg/kg of chloroquine by po alone. Compound 8h, which showed superior activity to 8a in mouse test, delayed the relapse of treated monkeys for 21-26 days at 30 mg/kg/day × 7 by oral.

Performance of the CareStart glucose-6-phosphate dehydrogenase (G6PD) rapid diagnostic test in Gressier, Haiti.

PubMed

von Fricken, Michael E; Weppelmann, Thomas A; Eaton, Will T; Masse, Roseline; Beau de Rochars, Madsen V E; Okech, Bernard A

2014-07-01

Administering primaquine (PQ) to treat malaria patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency can pose a serious risk of drug-induced hemolysis (DIH). New easy to use point-of-care rapid diagnostic tests are being developed as an alternative to labor-intensive spectrophotometric methods, but they require field testing before they can be used at scale. This study screened 456 participants in Gressier, Haiti using the Access Bio CareStart qualitative G6PD rapid detection test compared with the laboratory-based Trinity Biotech quantitative spectrophotometric assay. Findings suggest that the CareStart test was 90% sensitive for detecting individuals with severe deficiency and 84.8% sensitive for detecting individuals with moderate and severe deficiency compared with the Trinity Biotech assay. A high negative predictive value of 98.2% indicates excellent performance in determining those patients able to take PQ safely. The CareStart G6PD test holds much value for screening malaria patients to determine eligibility for PQ therapy. © The American Society of Tropical Medicine and Hygiene.

Implications of Plasmodium vivax Biology for Control, Elimination, and Research

PubMed Central

Olliaro, Piero L.; Barnwell, John W.; Barry, Alyssa; Mendis, Kamini; Mueller, Ivo; Reeder, John C.; Shanks, G. Dennis; Snounou, Georges; Wongsrichanalai, Chansuda

2016-01-01

This paper summarizes our current understanding of the biology of Plasmodium vivax, how it differs from Plasmodium falciparum, and how these differences explain the need for P. vivax-tailored interventions. The article further pinpoints knowledge gaps where investments in research are needed to help identify and develop such specific interventions. The principal obstacles to reduce and eventually eliminate P. vivax reside in 1) its higher vectorial capacity compared with P. falciparum due to its ability to develop at lower temperature and over a shorter sporogonic cycle in the vector, allowing transmission in temperate zones and making it less sensitive to vector control measures that are otherwise effective on P. falciparum; 2) the presence of dormant liver forms (hypnozoites), sustaining multiple relapsing episodes from a single infectious bite that cannot be diagnosed and are not susceptible to any available antimalarial except primaquine, with routine deployment restricted by toxicity; 3) low parasite densities, which are difficult to detect with current diagnostics leading to missed diagnoses and delayed treatments (and protracted transmission), coupled with 4) transmission stages (gametocytes) occurring early in acute infections, before infection is diagnosed. PMID:27799636

Importation of malaria into the USSR from Afghanistan, 1981-89.

PubMed Central

Sergiev, V. P.; Baranova, A. M.; Orlov, V. S.; Mihajlov, L. G.; Kouznetsov, R. L.; Neujmin, N. I.; Arsenieva, L. P.; Shahova, M. A.; Glagoleva, L. A.; Osipova, M. M.

1993-01-01

Between 1981 and 1989, a total of 7683 cases of Plasmodium vivax [corrected] malaria were imported into the USSR from Afghanistan, mainly by demobilized military personnel. For 23.8% of these cases the clinical manifestations appeared within a month of returning to the USSR, for 22.5% after 1-3 months, for 20% after 4-6 months, for 2% after > 1 year, and for 0.6% after > 2 years. For 13 patients the clinical manifestations of malaria appeared 3 years after returning from Afghanistan (up to 38 months). Nearly 69% of the patients did not take malaria prophylaxis at all while they were in Afghanistan, and 19% took chloroquine irregularly. Only 12.5% of the patients received a full course of prophylactic treatment with primaquine before leaving Afghanistan. A total of 56% of the cases were detected during the period most favourable for malaria transmission in the USSR (May-September) and of these, half were imported into formerly malarious areas of the country. Activation of a surveillance system greatly reduced the consequences of the massive importation of malaria, to which the local vectors were susceptible. PMID:8324858

Adding a single low-dose of primaquine (0.25 mg/kg) to artemether-lumefantrine did not compromise treatment outcome of uncomplicated Plasmodium falciparum malaria in Tanzania: a randomized, single-blinded clinical trial.

PubMed

Mwaiswelo, Richard; Ngasala, Billy; Jovel, Irina; Aydin-Schmidt, Berit; Gosling, Roland; Premji, Zul; Mmbando, Bruno; Björkman, Anders; Mårtensson, Andreas

2016-08-26

The World Health Organization (WHO) recently recommended the addition of a single low-dose of the gametocytocidal drug primaquine (PQ) to artemisinin-based combination therapy (ACT) in low transmission settings as a component of pre-elimination or elimination programmes. However, it is unclear whether that influences the ACT cure rate. The study assessed treatment outcome of artemether-lumefantrine (AL) plus a single PQ dose (0.25 mg/kg) versus standard AL regimen for treatment of acute uncomplicated Plasmodium falciparum malaria in Tanzania. A randomized, single-blinded, clinical trial was conducted in Yombo, Bagamoyo district, Tanzania. Acute uncomplicated P. falciparum malaria patients aged ≥1 year, with the exception of pregnant and lactating women, were enrolled and treated with AL plus a single PQ dose (0.25 mg/kg) or AL alone under supervision. PQ was administered together with the first AL dose. Clinical and laboratory assessments were performed at 0, 8, 24, 36, 48, 60, and 72 h and on days 7, 14, 21, and 28. The primary end-point was a polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) on day 28. Secondary outcomes included: fever and asexual parasitaemia clearance, proportion of patients with PCR-determined parasitaemia on day 3, and proportion of patients with Pfmdr1 N86Y and Pfcrt K76T on days 0, 3 and day of recurrent infection. Overall 220 patients were enrolled, 110 were allocated AL + PQ and AL, respectively. Parasite clearance by microscopy was fast, but PCR detectable parasitaemia on day 3 was 31/109 (28.4 %) and 29/108 (26.9 %) in patients treated with AL + PQ and AL, respectively (p = 0.79). Day 28 PCR-adjusted ACPR and re-infection rate was 105/105 (100 %) and 101/102 (99 %) (p = 0.31), and 5/107 (4.7 %) and 5/8 (4.8 %) (p = 0.95), in AL + PQ and AL arm, respectively. There was neither any statistically significant difference in the proportion of Pfmdr1 N86Y or Pfcrt K76T between treatment arms on days 0, 3 and day of recurrent infection, nor within treatment arms between days 0 and 3 or day 0 and day of recurrent infection. The new WHO recommendation of adding a single low-dose of PQ to AL did not compromise treatment outcome of uncomplicated P. falciparum malaria in Tanzania. Trial registration number NCT02090036.

Primaquine double dose for 7 days is inferior to single-dose treatment for 14 days in preventing Plasmodium vivax recurrent episodes in Suriname

PubMed Central

Mac Donald-Ottevanger, M Sigrid; Adhin, Malti R; Jitan, Jeetendra Kumar; Bretas, Gustavo; Vreden, Stephen GS

2018-01-01

Background Recurrent episodes of Plasmodium vivax are caused by dormant liver stages of the parasite, which are not eradicated by choloroquine. Therefore, effective treatment also includes the use of primaquine (PQ). However, this secondary preventive therapy is often not effective, mostly due to poor adherence to the relatively long treatment course, justifying a comparative study of the efficacy of different durations of PQ treatment. Materials and methods We included patients presenting with an acute and documented P. vivax infection from January 2006 to February 2008. All patients received chloroquine 25 mg/kg over a 3-day period. Subsequently, patients in group 7D received PQ 30 mg/day for 7 days, and patients in group 14D received standard PQ 15 mg/day for 14 days. All doses were given under supervision and patients were followed up for at least 6 months. The Kaplan–Meier method was used to estimate cumulative probability of recurrence up to 12 months after treatment initiation stratified by treatment group. Cox regression was used to assess possible determinants for recurrent parasitemia. Results Forty-seven of the 79 included patients (59.5%) were allocated to group 7D and 32 patients (40.5%) were allocated to group 14D. Recurrent parasitemia was detected in 31.9% of the cases in group 7D compared to 12.5% of the cases in group 14D (hazard ratio [HR] =3.36, 95% CI 1.11–10.16). Cumulative probability for recurrent parasitemia at 3, 6, and 12 months was 0.201 (95% CI 0.106–0.362), 0.312 (95% CI 0.190–0.485), and 0.424 (95% CI 0.274–0.615) for group 7D and 0.100 (95% CI 0.033–0.279), 0.100 (95% CI 0.033–0.279), and 0.138 (95% CI 0.054–0.327) for group 14D, respectively. When adjusted for possible confounders, differences in recurrent parasitemia remained significant between the two regimens in Cox regression analysis. Conclusion More than 30% of the patients receiving shorter treatment course had recurrent parasitemia, suggesting that the standard dose of 15 mg/day PQ for 14 days is more efficacious than 30 mg for 7 days in preventing P. vivax recurrent episodes. Furthermore, we suggest that P. vivax treatment in Suriname should be changed to PQ 30 mg/day for 14 days, as per Center for Disease Control and Prevention recommendation, in light of a recurrence rate of over 10%, even in group 14D. PMID:29317838

Glucose-6-phosphate dehydrogenase deficiency in people living in malaria endemic districts of Nepal.

PubMed

Ghimire, Prakash; Singh, Nihal; Ortega, Leonard; Rijal, Komal Raj; Adhikari, Bipin; Thakur, Garib Das; Marasini, Baburam

2017-05-23

Glucose-6-phosphate dehydrogenase (G6PD) is a rate limiting enzyme of the pentose phosphate pathway and is closely associated with the haemolytic disorders among patients receiving anti-malarial drugs, such as primaquine. G6PD deficiency (G6PDd) is an impending factor for radical treatment of malaria which affects the clearance of gametocytes from the blood and subsequent delay in the achievement of malaria elimination. The main objective of this study was to assess the prevalence of G6PD deficiency in six malaria endemic districts in Southern Nepal. A cross-sectional population based prevalence survey was conducted in six malaria endemic districts of Nepal, during April-Dec 2013. A total of 1341 blood samples were tested for G6PDd using two different rapid diagnostic test kits (Binax-Now ® and Care Start™). Equal proportions of participants from each district (n ≥ 200) were enrolled considering ethnic and demographic representation of the population groups. Out of total 1341 blood specimens collected from six districts, the overall prevalence of G6PDd was 97/1341; 7.23% on Binax Now and 81/1341; 6.0% on Care Start test. Higher prevalence was observed in male than females [Binax Now: male 10.2%; 53/521 versus female 5.4%; 44/820 (p = 0.003) and Care Start: male 8.4%; 44/521 versus female 4.5%; 37/820 (p = 0.003)]. G6PDd was higher in ethnic groups Rajbanshi (11.7%; 19/162) and Tharu (5.6%; 56/1005) (p = 0.006), major inhabitant of the endemic districts. Higher prevalence of G6PDd was found in Jhapa (22/224; 9.8%) and Morang districts (18/225; 8%) (p = 0.031). In a multivariate analysis, male were found at more risk for G6PDd than females, on Binax test (aOR = 1.97; CI 1.28-3.03; p = 0.002) and Care Start test (aOR = 1.86; CI 1.16-2.97; p = 0.009). The higher prevalence of G6PDd in certain ethnic group, gender and geographical region clearly demonstrates clustering of the cases and ascertained the risk groups within the population. This is the first study in Nepal which identified the vulnerable population groups for G6PDd in malaria endemic districts. The finding of this study warrants the need for G6PDd testing in vulnerable population groups in endemic districts, and also facilitates use of primaquine in mass supporting timely progress for malaria elimination.

Chloroquine Binding Reveals Flavin Redox Switch Function of Quinone Reductase 2*

PubMed Central

Leung, Kevin K. K.; Shilton, Brian H.

2013-01-01

Quinone reductase 2 (NQO2) is an FAD-linked enzyme and the only known human target of two antimalarial drugs, primaquine (PQ) and chloroquine (CQ). The structural differences between oxidized and reduced NQO2 and the structural basis for inhibition by PQ and CQ were investigated by x-ray crystallography. Structures of oxidized NQO2 in complex with PQ and CQ were solved at 1.4 Å resolution. CQ binds preferentially to reduced NQO2, and upon reduction of NQO2-CQ crystals, the space group changed from P212121 to P21, with 1-Å decreases in all three unit cell dimensions. The change in crystal packing originated in the negative charge and 4–5º bend in the reduced isoalloxazine ring of FAD, which resulted in a new mode of CQ binding and closure of a flexible loop (Phe126–Leu136) over the active site. This first structure of a reduced quinone reductase shows that reduction of the FAD cofactor and binding of a specific inhibitor lead to global changes in NQO2 structure and is consistent with a functional role for NQO2 as a flavin redox switch. PMID:23471972

Malaria medicines to address drug resistance and support malaria elimination efforts.

PubMed

Achan, Jane; Mwesigwa, Julia; Edwin, Chinagozi Precious; D'alessandro, Umberto

2018-01-01

Antimalarial drugs are essential weapons to fight malaria and have been used effectively since the 17 th century. However, P.falciparum resistance has been reported to almost all available antimalarial drugs, including artemisinin derivatives, raising concerns that this could jeopardize malaria elimination. Areas covered: In this article, we present a historical perspective of antimalarial drug resistance, review current evidence of resistance to available antimalarial drugs and discuss possible mitigating strategies to address this challenge. Expert commentary: The historical approach to drug resistance has been to change the national treatment policy to an alternative treatment. However, alternatives to artemisinin-based combination treatment are currently extremely limited. Innovative approaches utilizing available schizonticidal drugs such as triple combination therapies or multiple first line treatments could delay the emergence and spread of drug resistance. Transmission blocking drugs like primaquine may play a key role if given to a substantial proportion of malaria infected persons. Deploying antimalarial medicines in mass drug administration or mass screening and treatment campaigns could also contribute to containment efforts by eliminating resistant parasites in some settings. Ultimately, response to drug resistance should also include further investment in the development of new antimalarial drugs.

The Candidate Antimalarial Drug MMV665909 Causes Oxygen-Dependent mRNA Mistranslation and Synergizes with Quinoline-Derived Antimalarials

PubMed Central

Vallières, Cindy

2017-01-01

ABSTRACT To cope with growing resistance to current antimalarials, new drugs with novel modes of action are urgently needed. Molecules targeting protein synthesis appear to be promising candidates. We identified a compound (MMV665909) from the Medicines for Malaria Venture (MMV) Malaria Box of candidate antimalarials that could produce synergistic growth inhibition with the aminoglycoside antibiotic paromomycin, suggesting a possible action of the compound in mRNA mistranslation. This mechanism of action was substantiated with a Saccharomyces cerevisiae model using available reporters of mistranslation and other genetic tools. Mistranslation induced by MMV665909 was oxygen dependent, suggesting a role for reactive oxygen species (ROS). Overexpression of Rli1 (a ROS-sensitive, conserved FeS protein essential in mRNA translation) rescued inhibition by MMV665909, consistent with the drug's action on translation fidelity being mediated through Rli1. The MMV drug also synergized with major quinoline-derived antimalarials which can perturb amino acid availability or promote ROS stress: chloroquine, amodiaquine, and primaquine. The data collectively suggest translation fidelity as a novel target of antimalarial action and support MMV665909 as a promising drug candidate. PMID:28652237

Antimalarial activity of HIV-1 protease inhibitor in chromone series.

PubMed

Lerdsirisuk, Pradith; Maicheen, Chirattikan; Ungwitayatorn, Jiraporn

2014-12-01

Increasing parasite resistance to nearly all available antimalarial drugs becomes a serious problem to human health and necessitates the need to continue the search for new effective drugs. Recent studies have shown that clinically utilized HIV-1 protease (HIV-1 PR) inhibitors can inhibit the in vitro and in vivo growth of Plasmodium falciparum. In this study, a series of chromone derivatives possessing HIV-1 PR inhibitory activity has been tested for antimalarial activity against P. falciparum (K1 multi-drug resistant strain). Chromone 15, the potent HIV-1 PR inhibitor (IC50=0.65μM), was found to be the most potent antimalarial compound with IC50=0.95μM while primaquine and tafenoquine showed IC50=2.41 and 1.95μM, respectively. Molecular docking study of chromone compounds against plasmepsin II, an aspartic protease enzyme important in hemoglobin degradation, revealed that chromone 15 exhibited the higher binding affinity (binding energy=-13.24kcal/mol) than the known PM II inhibitors. Thus, HIV-1 PR inhibitor in chromone series has the potential to be a new class of antimalarial agent. Copyright © 2014 Elsevier Inc. All rights reserved.

Oral lipid-based nanoformulation of tafenoquine enhanced bioavailability and blood stage antimalarial efficacy and led to a reduction in human red blood cell loss in mice.

PubMed

Melariri, Paula; Kalombo, Lonji; Nkuna, Patric; Dube, Admire; Hayeshi, Rose; Ogutu, Benhards; Gibhard, Liezl; deKock, Carmen; Smith, Peter; Wiesner, Lubbe; Swai, Hulda

2015-01-01

Tafenoquine (TQ), a new synthetic analog of primaquine, has relatively poor bioavailability and associated toxicity in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. A microemulsion formulation of TQ (MTQ) with sizes <20 nm improved the solubility of TQ and enhanced the oral bioavailability from 55% to 99% in healthy mice (area under the curve 0 to infinity: 11,368±1,232 and 23,842±872 min·μmol/L) for reference TQ and MTQ, respectively. Average parasitemia in Plasmodium berghei-infected mice was four- to tenfold lower in the MTQ-treated group. In vitro antiplasmodial activities against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum indicated no change in half maximal inhibitory concentration, suggesting that the microemulsion did not affect the inherent activity of TQ. In a humanized mouse model of G6PD deficiency, we observed reduction in toxicity of TQ as delivered by MTQ at low but efficacious concentrations of TQ. We hereby report an enhancement in the solubility, bioavailibility, and efficacy of TQ against blood stages of Plasmodium parasites without a corresponding increase in toxicity.

Oral lipid-based nanoformulation of tafenoquine enhanced bioavailability and blood stage antimalarial efficacy and led to a reduction in human red blood cell loss in mice

PubMed Central

Melariri, Paula; Kalombo, Lonji; Nkuna, Patric; Dube, Admire; Hayeshi, Rose; Ogutu, Benhards; Gibhard, Liezl; deKock, Carmen; Smith, Peter; Wiesner, Lubbe; Swai, Hulda

2015-01-01

Tafenoquine (TQ), a new synthetic analog of primaquine, has relatively poor bioavailability and associated toxicity in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. A microemulsion formulation of TQ (MTQ) with sizes <20 nm improved the solubility of TQ and enhanced the oral bioavailability from 55% to 99% in healthy mice (area under the curve 0 to infinity: 11,368±1,232 and 23,842±872 min·μmol/L) for reference TQ and MTQ, respectively. Average parasitemia in Plasmodium berghei-infected mice was four- to tenfold lower in the MTQ-treated group. In vitro antiplasmodial activities against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum indicated no change in half maximal inhibitory concentration, suggesting that the microemulsion did not affect the inherent activity of TQ. In a humanized mouse model of G6PD deficiency, we observed reduction in toxicity of TQ as delivered by MTQ at low but efficacious concentrations of TQ. We hereby report an enhancement in the solubility, bioavailibility, and efficacy of TQ against blood stages of Plasmodium parasites without a corresponding increase in toxicity. PMID:25759576

Tafenoquine and its potential in the treatment and relapse prevention of Plasmodium vivax malaria: the evidence to date.

PubMed

Ebstie, Yehenew A; Abay, Solomon M; Tadesse, Wondmagegn T; Ejigu, Dawit A

2016-01-01

Despite declining global malaria incidence, the disease continues to be a threat to people living in endemic regions. In 2015, an estimated 214 million new malaria cases and 438,000 deaths due to malaria were recorded. Plasmodium vivax is the second most common cause of malaria next to Plasmodium falciparum. Vivax malaria is prevalent especially in Southeast Asia and the Horn of Africa, with enormous challenges in controlling the disease. Some of the challenges faced by vivax malaria-endemic countries include limited access to effective drugs treating liver stages of the parasite (schizonts and hypnozoites), emergence/spread of drug resistance, and misperception of vivax malaria as nonlethal. Primaquine, the only 8-aminoquinoline derivative approved by the US Food and Drug Administration, is intended to clear intrahepatic hypnozoites of P. vivax (radical cure). However, poor adherence to a prolonged treatment course, drug-induced hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency, and the emergence of resistance make it imperative to look for alternative drugs. Therefore, this review focuses on data accrued to date on tafenoquine and gives insight on the potential role of the drug in preventing relapse and radical cure of patients with vivax malaria.

Binding of anti-prion agents to glycosaminoglycans: Evidence from electronic absorption and circular dichroism spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zsila, Ferenc; Gedeon, Gabor

2006-08-11

The polyanionic glycosaminoglycans (GAGs) are intimately involved in the pathogenesis of protein conformational disorders such as amyloidosis and prion diseases. Several cationic agents are known to exhibit anti-prion activity but their mechanism of action is poorly understood. In this study, UV absorption and circular dichroism (CD) spectroscopic techniques were used to investigate the interaction between heparin and chondroitin-6-sulfate and anti-prion drugs including acridine, quinoline, and phenothiazine derivatives. UV band hypochromism of ({+-})-quinacrine, ({+-})-primaquine, tacrine, quinidine, chlorpromazine, and induced CD spectra of ({+-})-quinacrine upon addition of GAGs provided evidence for the GAG binding of these compounds. The association constants ({approx}10{sup 6}-10{supmore » 7} M{sup -1}) estimated from the UV titration curves show high-affinity drug-heparin interactions. Ionic strength-dependence of the absorption spectra suggested that the interaction between GAGs and the cationic drugs is principally electrostatic in nature. Drug binding differences of heparin and chondroitin-6-sulfate were attributed to their different negative charge density. These results call the attention to the alteration of GAG-prion/GAG-amyloid interactions by which these compounds might exert their anti-prion/anti-amyloidogenic activities.« less

Severe malaria vivax with sepsis bacterial: a case report

NASA Astrophysics Data System (ADS)

Tarigan, P.; Ginting, F.

2018-03-01

Malaria cases are often misdiagnosis by clinicians in tropical areas like Indonesia. Some cases show overlapping signs and symptoms of another infection that are common in the tropical areas such as typhoid, dengue, and leptospirosis. It can be misdiagnosed in practice and led to a wrong management that can end fatally. Severe malaria is usually caused by Plasmodium falciparum. P. vivax can also cause severe malaria but the cases reported are uncommon. Since infections with severe P. vivax that generally results in serious disease is quite uncommon in Indonesia, their identification and management are important. We report a case of severe malaria with sepsis, renal injury and hepatic impairment associated with malaria in a 70-year-old male. Clinical manifestations included anemia, sepsis, and elevated serum creatinine, urea, total bilirubin, and procalcitonin. The rapid diagnostic test for malaria and microscopic examination of blood smears were positive for P. vivax. The patient was treated as severe malaria with intravenous artesunate for six days, followed by oral treatment of primaquine for 14 days. Intravenous fluid therapy, antipyretic, anti-malaria and antibiotic treatment were administered. The patient was stable and then discharged from the hospital. The prognosis depends much on early diagnosis and appropriate supportive treatment.

Epidemiology of Plasmodium vivax in Indonesia.

PubMed

Surjadjaja, Claudia; Surya, Asik; Baird, J Kevin

2016-12-28

Endemic malaria occurs across much of the vast Indonesian archipelago. All five species of Plasmodium known to naturally infect humans occur here, along with 20 species of Anopheles mosquitoes confirmed as carriers of malaria. Two species of plasmodia cause the overwhelming majority and virtually equal shares of malaria infections in Indonesia: Plasmodium falciparum and Plasmodium vivax The challenge posed by P. vivax is especially steep in Indonesia because chloroquine-resistant strains predominate, along with Chesson-like strains that relapse quickly and multiple times at short intervals in almost all patients. Indonesia's hugely diverse human population carries many variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency, most of them exhibiting severely impaired enzyme activity. Therefore, the patients most likely to benefit from primaquine therapy by preventing aggressive relapse, may also be most likely to suffer harm without G6PD deficiency screening. Indonesia faces the challenge of controlling and eventually eliminating malaria across > 13,500 islands stretching > 5,000 km and an enormous diversity of ecological, ethnographic, and socioeconomic settings, and extensive human migrations. This article describes the occurrence of P. vivax in Indonesia and the obstacles faced in eliminating its transmission. © The American Society of Tropical Medicine and Hygiene.

Implications of Plasmodium vivax Biology for Control, Elimination, and Research.

PubMed

Olliaro, Piero L; Barnwell, John W; Barry, Alyssa; Mendis, Kamini; Mueller, Ivo; Reeder, John C; Shanks, G Dennis; Snounou, Georges; Wongsrichanalai, Chansuda

2016-12-28

This paper summarizes our current understanding of the biology of Plasmodium vivax, how it differs from Plasmodium falciparum, and how these differences explain the need for P. vivax-tailored interventions. The article further pinpoints knowledge gaps where investments in research are needed to help identify and develop such specific interventions. The principal obstacles to reduce and eventually eliminate P. vivax reside in 1) its higher vectorial capacity compared with P. falciparum due to its ability to develop at lower temperature and over a shorter sporogonic cycle in the vector, allowing transmission in temperate zones and making it less sensitive to vector control measures that are otherwise effective on P. falciparum; 2) the presence of dormant liver forms (hypnozoites), sustaining multiple relapsing episodes from a single infectious bite that cannot be diagnosed and are not susceptible to any available antimalarial except primaquine, with routine deployment restricted by toxicity; 3) low parasite densities, which are difficult to detect with current diagnostics leading to missed diagnoses and delayed treatments (and protracted transmission), coupled with 4) transmission stages (gametocytes) occurring early in acute infections, before infection is diagnosed. © The American Society of Tropical Medicine and Hygiene.

Epidemiology of Plasmodium vivax in Indonesia

PubMed Central

Surjadjaja, Claudia; Surya, Asik; Baird, J. Kevin

2016-01-01

Endemic malaria occurs across much of the vast Indonesian archipelago. All five species of Plasmodium known to naturally infect humans occur here, along with 20 species of Anopheles mosquitoes confirmed as carriers of malaria. Two species of plasmodia cause the overwhelming majority and virtually equal shares of malaria infections in Indonesia: Plasmodium falciparum and Plasmodium vivax. The challenge posed by P. vivax is especially steep in Indonesia because chloroquine-resistant strains predominate, along with Chesson-like strains that relapse quickly and multiple times at short intervals in almost all patients. Indonesia's hugely diverse human population carries many variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency, most of them exhibiting severely impaired enzyme activity. Therefore, the patients most likely to benefit from primaquine therapy by preventing aggressive relapse, may also be most likely to suffer harm without G6PD deficiency screening. Indonesia faces the challenge of controlling and eventually eliminating malaria across > 13,500 islands stretching > 5,000 km and an enormous diversity of ecological, ethnographic, and socioeconomic settings, and extensive human migrations. This article describes the occurrence of P. vivax in Indonesia and the obstacles faced in eliminating its transmission. PMID:27708185

A Comparison of Three Quantitative Methods to Estimate G6PD Activity in the Chittagong Hill Tracts, Bangladesh.

PubMed

Ley, Benedikt; Alam, Mohammad Shafiul; O'Donnell, James J; Hossain, Mohammad Sharif; Kibria, Mohammad Golam; Jahan, Nusrat; Khan, Wasif A; Thriemer, Kamala; Chatfield, Mark D; Price, Ric N; Richards, Jack S

2017-01-01

Glucose-6-phosphate-dehydrogenase-deficiency (G6PDd) is a major risk factor for primaquine-induced haemolysis. There is a need for improved point-of-care and laboratory-based G6PD diagnostics to unsure safe use of primaquine. G6PD activities of participants in a cross-sectional survey in Bangladesh were assessed using two novel quantitative assays, the modified WST-8 test and the CareStart™ G6PD Biosensor (Access Bio), The results were compared with a gold standard UV spectrophotometry assay (Randox). The handheld CareStart™ Hb instrument (Access Bio) is designed to be a companion instrument to the CareStart™ G6PD biosensor, and its performance was compared to the well-validated HemoCue™ method. All quantitative G6PD results were normalized with the HemoCue™ result. A total of 1002 individuals were enrolled. The adjusted male median (AMM) derived by spectrophotometry was 7.03 U/g Hb (interquartile range (IQR): 5.38-8.69), by WST-8 was 7.03 U/g Hb (IQR: 5.22-8.16) and by Biosensor was 8.61 U/g Hb (IQR: 6.71-10.08). The AMM between spectrophotometry and WST-8 did not differ (p = 1.0) but differed significantly between spectrophotometry and Biosensor (p<0.01). Both, WST-8 and Biosensor were correlated with spectrophotometry (rs = 0.5 and rs = 0.4, both p<0.001). The mean difference in G6PD activity was -0.12 U/g Hb (95% limit of agreement (95% LoA): -5.45 to 5.20) between spectrophotometry and WST-8 and -1.74U/g Hb (95% LoA: -7.63 to 4.23) between spectrophotometry and Biosensor. The WST-8 identified 55.1% (49/89) and the Biosensor 19.1% (17/89) of individuals with G6PD activity <30% by spectrophotometry. Areas under the ROC curve did not differ significantly for the WST-8 and Biosensor irrespective of the cut-off activity applied (all p>0.05). Sensitivity and specificity for detecting G6PD activity <30% was 0.55 (95% confidence interval (95%CI): 0.44-0.66) and 0.98 (95%CI: 0.97-0.99) respectively for the WST-8 and 0.19 (95%CI: 0.12-0.29) and 0.99 (95%CI: 0.98-0.99) respectively for the Biosensor. Hb concentrations measured by HemoCue™ and CareStart™ Hb were strongly correlated (rs = 0.8, p<0.001, mean difference = 0.09 g Hb/dL, 95% LoA: -2.15 to 2.34). WST-8 and the CareStart™ G6PD Biosensor represent advances in G6PD diagnostics in resource poor settings, but will require further development before clinical deployment. The CareStart™ Hb instrument produced a precise measure of haemoglobin concentration.

A Comparison of Three Quantitative Methods to Estimate G6PD Activity in the Chittagong Hill Tracts, Bangladesh

PubMed Central

Ley, Benedikt; Alam, Mohammad Shafiul; O’Donnell, James J.; Hossain, Mohammad Sharif; Kibria, Mohammad Golam; Jahan, Nusrat; Khan, Wasif A.; Thriemer, Kamala; Chatfield, Mark D.; Price, Ric N.; Richards, Jack S.

2017-01-01

Background Glucose-6-phosphate-dehydrogenase-deficiency (G6PDd) is a major risk factor for primaquine-induced haemolysis. There is a need for improved point-of-care and laboratory-based G6PD diagnostics to unsure safe use of primaquine. Methods G6PD activities of participants in a cross-sectional survey in Bangladesh were assessed using two novel quantitative assays, the modified WST-8 test and the CareStart™ G6PD Biosensor (Access Bio), The results were compared with a gold standard UV spectrophotometry assay (Randox). The handheld CareStart™ Hb instrument (Access Bio) is designed to be a companion instrument to the CareStart™ G6PD biosensor, and its performance was compared to the well-validated HemoCue™ method. All quantitative G6PD results were normalized with the HemoCue™ result. Results A total of 1002 individuals were enrolled. The adjusted male median (AMM) derived by spectrophotometry was 7.03 U/g Hb (interquartile range (IQR): 5.38–8.69), by WST-8 was 7.03 U/g Hb (IQR: 5.22–8.16) and by Biosensor was 8.61 U/g Hb (IQR: 6.71–10.08). The AMM between spectrophotometry and WST-8 did not differ (p = 1.0) but differed significantly between spectrophotometry and Biosensor (p<0.01). Both, WST-8 and Biosensor were correlated with spectrophotometry (rs = 0.5 and rs = 0.4, both p<0.001). The mean difference in G6PD activity was -0.12 U/g Hb (95% limit of agreement (95% LoA): -5.45 to 5.20) between spectrophotometry and WST-8 and -1.74U/g Hb (95% LoA: -7.63 to 4.23) between spectrophotometry and Biosensor. The WST-8 identified 55.1% (49/89) and the Biosensor 19.1% (17/89) of individuals with G6PD activity <30% by spectrophotometry. Areas under the ROC curve did not differ significantly for the WST-8 and Biosensor irrespective of the cut-off activity applied (all p>0.05). Sensitivity and specificity for detecting G6PD activity <30% was 0.55 (95% confidence interval (95%CI): 0.44–0.66) and 0.98 (95%CI: 0.97–0.99) respectively for the WST-8 and 0.19 (95%CI: 0.12–0.29) and 0.99 (95%CI: 0.98–0.99) respectively for the Biosensor. Hb concentrations measured by HemoCue™ and CareStart™ Hb were strongly correlated (rs = 0.8, p<0.001, mean difference = 0.09 g Hb/dL, 95% LoA: -2.15 to 2.34). Conclusion WST-8 and the CareStart™ G6PD Biosensor represent advances in G6PD diagnostics in resource poor settings, but will require further development before clinical deployment. The CareStart™ Hb instrument produced a precise measure of haemoglobin concentration. PMID:28121993

Glucose-6-phosphate dehydrogenase deficiency among Yemeni children residing in malaria-endemic areas of Hodeidah governorate and evaluation of a rapid diagnostic test for its detection.

PubMed

Abdul-Ghani, Rashad; Mahdy, Mohammed A K; Saif-Ali, Reyadh; Alkubati, Sameer A; Alqubaty, Abdulhabib R; Al-Mikhlafy, Abdullah A; Al-Eryani, Samira M; Al-Mekhlafi, Abdusalam M; Alhaj, Ali

2016-06-21

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common genetic enzymopathy worldwide, is associated with an acute haemolytic anaemia in individuals exposed to primaquine. The present study aimed to determine G6PD deficiency among Yemeni children in malaria-endemic areas as well as to assess the performance of the CareStart™ G6PD rapid diagnostic test (RDT) for its detection. A cross-sectional study recruiting 400 children from two rural districts in Hodeidah governorate was conducted. Socio-demographic data and blood samples were collected and G6PD deficiency was qualitatively detected in fresh blood in the field using the CareStart™ G6PD RDT, while the enzymatic assay was used to quantitatively measure enzyme activity. Performance of the CareStart™ G6PD RDT was assessed by calculating its sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) against the reference enzymatic assay. The ranges of enzyme activity were 0.14-18.45 and 0.21-15.94 units/g haemoglobin (U/gHb) for males and females, respectively. However, adjusted male median G6PD activity was 5.0 U/gHb. Considering the adjusted male median as representing 100 % normal enzyme activity, the prevalence rates of G6PD deficiency were 12.0 and 2.3 % at the cut-off activities of ≤60 and ≤10 %, respectively. Multivariable analysis showed that gender, district of residence and consanguinity between parents were independent risk factors for G6PD deficiency at the cut-off activity of ≤30 % of normal. The CareStart™ G6PD RDT showed 100 % sensitivity and NPV for detecting G6PD deficiency at the cut-off activities of ≤10 and ≤20 % of normal activity compared to the reference enzymatic method. However, it showed specificity levels of 90.0 and 95.4 % as well as positive/deficient predictive values (PPVs) of 18.0 and 66.0 % at the cut-off activities of ≤10 and ≤20 %, respectively, compared to the reference method. G6PD deficiency with enzyme activity of ≤60 % of normal is prevalent among 12.0 % of children residing in malaria-endemic areas of Hodeidah governorate, with 2.3 % having severe G6PD deficiency. Gender, district of residence and consanguinity between parents are significant independent predictors of G6PD deficiency at the cut-off activity of ≤30 % of normal among children in malaria-endemic areas of Hodeidah. The CareStart™ G6PD RDT proved reliable as a point-of-care test to screen for severely G6PD-deficient patients, with 100 % sensitivity and NPV, and it can be used for making clinical decisions prior to the administration of primaquine in malaria elimination strategies.

UK malaria treatment guidelines 2016.

PubMed

Lalloo, David G; Shingadia, Delane; Bell, David J; Beeching, Nicholas J; Whitty, Christopher J M; Chiodini, Peter L

2016-06-01

1.Malaria is the tropical disease most commonly imported into the UK, with 1300-1800 cases reported each year, and 2-11 deaths. 2. Approximately three quarters of reported malaria cases in the UK are caused by Plasmodium falciparum, which is capable of invading a high proportion of red blood cells and rapidly leading to severe or life-threatening multi-organ disease. 3. Most non-falciparum malaria cases are caused by Plasmodium vivax; a few cases are caused by the other species of plasmodium: Plasmodium ovale, Plasmodium malariae or Plasmodium knowlesi. 4. Mixed infections with more than one species of parasite can occur; they commonly involve P. falciparum with the attendant risks of severe malaria. 5. There are no typical clinical features of malaria; even fever is not invariably present. Malaria in children (and sometimes in adults) may present with misleading symptoms such as gastrointestinal features, sore throat or lower respiratory complaints. 6. A diagnosis of malaria must always be sought in a feverish or sick child or adult who has visited malaria-endemic areas. Specific country information on malaria can be found at http://travelhealthpro.org.uk/. P. falciparum infection rarely presents more than six months after exposure but presentation of other species can occur more than a year after exposure. 7. Management of malaria depends on awareness of the diagnosis and on performing the correct diagnostic tests: the diagnosis cannot be excluded until more than one blood specimen has been examined. Other travel related infections, especially viral haemorrhagic fevers, should also be considered. 8. The optimum diagnostic procedure is examination of thick and thin blood films by an expert to detect and speciate the malarial parasites. P. falciparum and P. vivax (depending upon the product) malaria can be diagnosed almost as accurately using rapid diagnostic tests (RDTs) which detect plasmodial antigens. RDTs for other Plasmodium species are not as reliable. 9. Most patients treated for P. falciparum malaria should be admitted to hospital for at least 24 h as patients can deteriorate suddenly, especially early in the course of treatment. In specialised units seeing large numbers of patients, outpatient treatment may be considered if specific protocols for patient selection and follow up are in place. 10. Uncomplicated P. falciparum malaria should be treated with an artemisinin combination therapy (Grade 1A). Artemether-lumefantrine (Riamet(®)) is the drug of choice (Grade 2C) and dihydroartemisinin-piperaquine (Eurartesim(®)) is an alternative. Quinine or atovaquone-proguanil (Malarone(®)) can be used if an ACT is not available. Quinine is highly effective but poorly-tolerated in prolonged treatment and should be used in combination with an additional drug, usually oral doxycycline. 11. Severe falciparum malaria, or infections complicated by a relatively high parasite count (more than 2% of red blood cells parasitized) should be treated with intravenous therapy until the patient is well enough to continue with oral treatment. Severe malaria is a rare complication of P. vivax or P. knowlesi infection and also requires parenteral therapy. 12. The treatment of choice for severe or complicated malaria in adults and children is intravenous artesunate (Grade 1A). Intravenous artesunate is unlicensed in the EU but is available in many centres. The alternative is intravenous quinine, which should be started immediately if artesunate is not available (Grade 1A). Patients treated with intravenous quinine require careful monitoring for hypoglycemia. 13. Patients with severe or complicated malaria should be managed in a high-dependency or intensive care environment. They may require haemodynamic support and management of: acute respiratory distress syndrome, disseminated intravascular coagulation, acute kidney injury, seizures, and severe intercurrent infections including Gram-negative bacteraemia/septicaemia. 14. Children with severe malaria should also be treated with empirical broad spectrum antibiotics until bacterial infection can be excluded (Grade 1B). 15. Haemolysis occurs in approximately 10-15% patients following intravenous artesunate treatment. Haemoglobin concentrations should be checked approximately 14 days following treatment in those treated with IV artemisinins (Grade 2C). 16. Falciparum malaria in pregnancy is more likely to be complicated: the placenta contains high levels of parasites, stillbirth or early delivery may occur and diagnosis can be difficult if parasites are concentrated in the placenta and scanty in the blood. 17. Uncomplicated falciparum malaria in the second and third trimester of pregnancy should be treated with artemether-lumefantrine (Grade 2B). Uncomplicated falciparum malaria in the first trimester of pregnancy should usually be treated with quinine and clindamycin but specialist advice should be sought. Severe malaria in any trimester of pregnancy should be treated as for any other patient with artesunate preferred over quinine (Grade 1C). 18. Children with uncomplicated malaria should be treated with an ACT (artemether-lumefantrine or dihydroartemisinin-piperaquine) as first line treatment (Grade 1A). Quinine with doxycycline or clindamycin, or atovaquone-proguanil at appropriate doses for weight can also be used. Doxycycline should not be given to children under 12 years. 19. Either an oral ACT or chloroquine can be used for the treatment of non-falciparum malaria. An oral ACT is preferred for a mixed infection, if there is uncertainty about the infecting species, or for P. vivax infection from areas where chloroquine resistance is common (Grade 1B). 20. Dormant parasites (hypnozoites) persist in the liver after treatment of P. vivax or P. ovale infection: the only currently effective drug for eradication of hypnozoites is primaquine (1A). Primaquine is more effective at preventing relapse if taken at the same time as chloroquine (Grade 1C). 21. Primaquine should be avoided or given with caution under expert supervision in patients with Glucose-6-phosphate dehydrogenase deficiency (G6PD), in whom it may cause severe haemolysis. 22. Primaquine (for eradication of P. vivax or P. ovale hypnozoites) is contraindicated in pregnancy and when breastfeeding (until the G6PD status of child is known); after initial treatment for these infections a pregnant woman should take weekly chloroquine prophylaxis until after delivery or cessation of breastfeeding when hypnozoite eradication can be considered. 23. An acute attack of malaria does not confer protection from future attacks: individuals who have had malaria should take effective anti-mosquito precautions and chemoprophylaxis during future visits to endemic areas. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Paper Test Cards for Presumptive Testing of Very Low Quality Antimalarial Medications

PubMed Central

Weaver, Abigail A.; Lieberman, Marya

2015-01-01

Carrying out chemical analysis of antimalarials to detect low-quality medications before they reach a patient is a costly venture. Here, we show that a library of chemical color tests embedded on a paper card can presumptively identify formulations corresponding to very low quality antimalarial drugs. The presence or absence of chloroquine (CQ), doxycycline (DOX), quinine, sulfadoxine, pyrimethamine, and primaquine antimalarial medications, in addition to fillers used in low-quality pharmaceuticals, are indicated by patterns of colors that are generated on the test cards. Test card sensitivity for detection of these pure components ranges from 90% to 100% with no false positives in the absence of pharmaceutical. The color intensities from reactions characteristic of CQ or DOX allowed visual detection of formulations of these medications cut with 60% or 100% filler, although samples cut with 30% filler could not be reliably detected colorimetrically. However, the addition of unexpected fillers, even in 30% quantities, or substitute pharmaceuticals, could sometimes be detected by other color reactions on the test cards. Tests are simple and inexpensive enough to be carried out in clinics, pharmacies, and ports of entry and could provide a screening method to presumptively indicate very low quality medicines throughout the supply chain. PMID:25897064

G6PD deficiency in Latin America: systematic review on prevalence and variants

PubMed Central

Monteiro, Wuelton M; Val, Fernando FA; Siqueira, André M; Franca, Gabriel P; Sampaio, Vanderson S; Melo, Gisely C; Almeida, Anne CG; Brito, Marcelo AM; Peixoto, Henry M; Fuller, Douglas; Bassat, Quique; Romero, Gustavo AS; Maria Regina F, Oliveira; Marcus Vinícius G, Lacerda

2014-01-01

Plasmodium vivax radical cure requires the use of primaquine (PQ), a drug that induces haemolysis in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals, which further hampers malaria control efforts. The aim of this work was to study the G6PDd prevalence and variants in Latin America (LA) and the Caribbean region. A systematic search of the published literature was undertaken in August 2013. Bibliographies of manuscripts were also searched and additional references were identified. Low prevalence rates of G6PDd were documented in Argentina, Bolivia, Mexico, Peru and Uruguay, but studies from Curaçao, Ecuador, Jamaica, Saint Lucia, Suriname and Trinidad, as well as some surveys carried out in areas of Brazil, Colombia and Cuba, have shown a high prevalence (> 10%) of G6PDd. The G6PD A-202A mutation was the variant most broadly distributed across LA and was identified in 81.1% of the deficient individuals surveyed. G6PDd is a frequent phenomenon in LA, although certain Amerindian populations may not be affected, suggesting that PQ could be safely used in these specific populations. Population-wide use of PQ as part of malaria elimination strategies in LA cannot be supported unless a rapid, accurate and field-deployable G6PDd diagnostic test is made available. PMID:25141282

Plasmodium falciparum Calcium-Dependent Protein Kinase 2 Is Critical for Male Gametocyte Exflagellation but Not Essential for Asexual Proliferation

PubMed Central

Molina-Cruz, Alvaro; Brzostowski, Joseph; Mu, Jianbing

2017-01-01

ABSTRACT Drug development efforts have focused mostly on the asexual blood stages of the malaria parasite Plasmodium falciparum. Except for primaquine, which has its own limitations, there are no available drugs that target the transmission of the parasite to mosquitoes. Therefore, there is a need to validate new parasite proteins that can be targeted for blocking transmission. P. falciparum calcium-dependent protein kinases (PfCDPKs) play critical roles at various stages of the parasite life cycle and, importantly, are absent in the human host. These features mark them as attractive drug targets. In this study, using CRISPR/Cas9 we successfully knocked out PfCDPK2 from blood-stage parasites, which was previously thought to be an indispensable protein. The growth rate of the PfCDPK2 knockout (KO) parasites was similar to that of wild-type parasites, confirming that PfCDPK2 function is not essential for the asexual proliferation of the parasite in vitro. The mature male and female gametocytes of PfCDPK2 KO parasites become round after induction. However, they fail to infect female Anopheles stephensi mosquitoes due to a defect(s) in male gametocyte exflagellation and possibly in female gametes. PMID:29042501

Tafenoquine and its potential in the treatment and relapse prevention of Plasmodium vivax malaria: the evidence to date

PubMed Central

Ebstie, Yehenew A; Abay, Solomon M; Tadesse, Wondmagegn T; Ejigu, Dawit A

2016-01-01

Despite declining global malaria incidence, the disease continues to be a threat to people living in endemic regions. In 2015, an estimated 214 million new malaria cases and 438,000 deaths due to malaria were recorded. Plasmodium vivax is the second most common cause of malaria next to Plasmodium falciparum. Vivax malaria is prevalent especially in Southeast Asia and the Horn of Africa, with enormous challenges in controlling the disease. Some of the challenges faced by vivax malaria-endemic countries include limited access to effective drugs treating liver stages of the parasite (schizonts and hypnozoites), emergence/spread of drug resistance, and misperception of vivax malaria as nonlethal. Primaquine, the only 8-aminoquinoline derivative approved by the US Food and Drug Administration, is intended to clear intrahepatic hypnozoites of P. vivax (radical cure). However, poor adherence to a prolonged treatment course, drug-induced hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency, and the emergence of resistance make it imperative to look for alternative drugs. Therefore, this review focuses on data accrued to date on tafenoquine and gives insight on the potential role of the drug in preventing relapse and radical cure of patients with vivax malaria. PMID:27528800

Ethical aspects of malaria control and research.

PubMed

Jamrozik, Euzebiusz; de la Fuente-Núñez, Vânia; Reis, Andreas; Ringwald, Pascal; Selgelid, Michael J

2015-12-22

Malaria currently causes more harm to human beings than any other parasitic disease, and disproportionally affects low-income populations. The ethical issues raised by efforts to control or eliminate malaria have received little explicit analysis, in comparison with other major diseases of poverty. While some ethical issues associated with malaria are similar to those that have been the subject of debate in the context of other infectious diseases, malaria also raises distinct ethical issues in virtue of its unique history, epidemiology, and biology. This paper provides preliminary ethical analyses of the especially salient issues of: (i) global health justice, (ii) universal access to malaria control initiatives, (iii) multidrug resistance, including artemisinin-based combination therapy (ACT) resistance, (iv) mandatory screening, (v) mass drug administration, (vi) benefits and risks of primaquine, and (vii) malaria in the context of blood donation and transfusion. Several ethical issues are also raised by past, present and future malaria research initiatives, in particular: (i) controlled infection studies, (ii) human landing catches, (iii) transmission-blocking vaccines, and (iv) genetically-modified mosquitoes. This article maps the terrain of these major ethical issues surrounding malaria control and elimination. Its objective is to motivate further research and discussion of ethical issues associated with malaria--and to assist health workers, researchers, and policy makers in pursuit of ethically sound malaria control practice and policy.

Summary of recommendations for the prevention of malaria by the Committee to Advise on Tropical Medicine and Travel (CATMAT)

PubMed Central

Boggild, A; Brophy, J; Charlebois, P; Crockett, M; Geduld, J; Ghesquiere, W; McDonald, P; Plourde, P; Teitelbaum, P; Tepper, M; Schofield, S; McCarthy, A

2014-01-01

Background On behalf of the Public Health Agency of Canada, the Committee to Advise on Tropical Medicine and Travel (CATMAT) developed the Canadian Recommendations for the Prevention and Treatment of Malaria Among International Travellers for Canadian health care providers who are preparing patients for travel to malaria-endemic areas and treating travellers who have returned ill. Objective To provide guidelines on risk assessment and prevention of malaria Methods CATMAT reviewed all major sources of information on malaria prevention, as well as recent research and national and international epidemiological data, to tailor guidelines to the Canadian context. The evidence-based medicine recommendations were developed with associated rating scales for the strength and quality of the evidence. Recommendations Used together and correctly, personal protective measures (PPM) and chemoprophylaxis very effectively protect against malaria infection. PPM include protecting accommodation areas from mosquitoes, wearing appropriate clothing, using bed nets pre-treated with insecticide and applying topical insect repellant (containing 20%–30% DEET or 20% icaridin) to exposed skin. Selecting the most appropriate chemoprophylaxis involves assessment of the traveller’s itinerary to establish his/her malaria risk profile as well as potential drug resistance issues. Antimalarials available on prescription in Canada include chloroquine (or hydroxychloroquine), atovaquone-proguanil, doxycycline, mefloquine and primaquine. PMID:29769893

New treatment policy of malaria as a part of malaria control program in Indonesia.

PubMed

Kusriastuti, Rita; Surya, Asik

2012-07-01

Malaria control program is one of the oldest program in the Ministry of Health (MoH) Republic of Indonesia. Started with effort to eradicate malaria in 1959 through Malaria Eradication Command well known as KOPEM (Komando Pembasmian Malaria) then it evolves to Malaria Control Program, Roll Back Malaria Program, and the current Malaria Elimination Program. In terms of diagnostic and treatment, the policy has formulated by strictly follow evidence-based principles as well as technical guided from World Health Organization (WHO). In 2004, based on numerous researches conducted in Indonesia the use of chloroquine was stopped and artemisinin-based combination therapy (ACT) was then initiated. For severe cases the use of intravenous (iv) Artesunate for cases treated in hospitals and intramuscular (im) Arthemeter for cases treated in the primary care setting were also introduced. ACT, Artesunate iv, and Artemether im, all are provided nationwide through the procurement system. For radical treatment, the recommendation in Indonesia is to add primaquine (PQ) to ACT for Plasmodium vivax and Plasmodium ovale infections to prevent relapses and for Plasmodium Falciparum infection to kill the gametocytes. These recommendations put hope to reduce malaria mortality to zero and eventually with other interventions will eliminate malaria from the country by 2030. The dissemination of this information is important for the policy to apply in practice across the country.

The G6PD flow-cytometric assay is a reliable tool for diagnosis of G6PD deficiency in women and anaemic subjects.

PubMed

Bancone, Germana; Kalnoky, Michael; Chu, Cindy S; Chowwiwat, Nongnud; Kahn, Maria; Malleret, Benoit; Wilaisrisak, Pornpimon; Rénia, Laurent; Domingo, Gonzalo J; Nosten, Francois

2017-08-29

Glucose-6-phosphate dehydrogenase (G6PD) activity is essential for redox equilibrium of red blood cells (RBCs) and, when compromised, the RBCs are more susceptible to haemolysis. 8-aminoquinolines (primaquine and tafenoquine) are used for the radical curative treatment of Plasmodium vivax malaria and can cause haemolysis in G6PD deficient subjects. Haemolytic risk is dependent on treatment dose and patient G6PD status but ultimately it correlates with the number of G6PD deficient RBCs. The G6PD spectrophotometric assay reliably identifies deficient subjects but is less reliable in heterozygous females, especially when other blood conditions are present. In this work we analysed samples with a range of G6PD phenotypes and haematologic conditions from 243 healthy volunteers of Asian or African-American heritage using both the spectrophotomeric assay and the G6PD flow-cytometric assay. Overall 18.5% of subjects (29.3% of Asian females) presented with anaemia, associated with decreased RBCs volume (MCV) and reticulocytosis; the flow-cytometric assay showed good correlation with the spectrophotometric assay (Pearson's r 0.918-0.957) and was less influenced by haemoglobin concentration, number of RBCs and number of reticulocytes. This resulted in more precise quantification of the number of G6PD deficient RBCs and presumably higher predictive power of drug induced haemolytic risk.

Characterization of G6PD Genotypes and Phenotypes on the Northwestern Thailand-Myanmar Border

PubMed Central

Somsakchaicharoen, Raweewan; Chowwiwat, Nongnud; Parker, Daniel M.; Charunwatthana, Prakaykaew; White, Nicholas J.; Nosten, François H.

2014-01-01

Mutations in the glucose-6-phosphate dehydrogenase (G6PD) gene result in red blood cells with increased susceptibility to oxidative damage. Significant haemolysis can be caused by primaquine and other 8-aminoquinoline antimalarials used for the radical treatment of Plasmodium vivax malaria. The distribution and phenotypes of mutations causing G6PD deficiency in the male population of migrants and refugees in a malaria endemic region on the Thailand-Myanmar border were characterized. Blood samples for G6PD fluorescent spot test (FST), G6PD genotyping, and malaria testing were taken from 504 unrelated males of Karen and Burman ethnicities presenting to the outpatient clinics. The overall frequency of G6PD deficiency by the FST was 13.7%. Among the deficient subjects, almost 90% had the Mahidol variant (487G>A) genotype. The remaining subjects had Chinese-4 (392G>T), Viangchan (871G>A), Açores (595A>G), Seattle (844G>C) and Mediterranean (563C>T) variants. Quantification of G6PD activity was performed using a modification of the standard spectrophotometric assay on a subset of 24 samples with Mahidol, Viangchan, Seattle and Chinese-4 mutations; all samples showed a residual enzymatic activity below 10% of normal and were diagnosed correctly by the FST. Further studies are needed to characterise the haemolytic risk of using 8-aminoquinolines in patients with these genotypes. PMID:25536053

Rapid epidemiologic assessment of glucose-6-phosphate dehydrogenase deficiency in malaria-endemic areas in Southeast Asia using a novel diagnostic kit.

PubMed

Jalloh, A; Tantular, I S; Pusarawati, S; Kawilarang, A P; Kerong, H; Lin, K; Ferreira, M U; Matsuoka, H; Arai, M; Kita, K; Kawamoto, F

2004-05-01

We recently reported a new rapid screening method for glucose-6-phosphate dehydrogenase (G6PD) deficiency. This method incorporates a new formazan substrate (WST-8) and is capable of detecting heterozygous females both qualitatively and quantitatively. Here, we report its evaluation during field surveys at three malaria centres and in malaria-endemic villages of Myanmar and Indonesia, either alone or in combination with a rapid on-site diagnosis of malaria. A total of 57 severe (45 males and 12 females) and 34 mild (five males and 29 females) cases of G6PD deficiency were detected among 855 subjects in Myanmar whilst 30 severe (25 males and five females) and 23 mild (six males and 17 females) cases were found among 1286 subjects in Indonesia. In all cases, severe deficiency was confirmed with another formazan method but due to limitations in its detection threshold, mild cases were misdiagnosed as G6PD-normal by this latter method. Our results indicate that the novel method can qualitatively detect both severely deficient subjects as well as heterozygous females in the field. The antimalarial drug, primaquine, was safely prescribed to Plasmodium vivax-infected patients in Myanmar. Our new, rapid screening method may be essential for the diagnosis of G6PD deficiency particularly in rural areas without electricity, and can be recommended for use in malaria control programmes.

The first evaluation of glucose-6-phosphate dehydrogenase deficiency (G6PD) gene mutation in malaria-endemic region at South Central Timor (SCT) district, Eastern Indonesia 2015-2016

NASA Astrophysics Data System (ADS)

Hutagalung, J.; Kusnanto, H.; Supargiyono; Sadewa, A. H.; Satyagraha, A. W.

2018-03-01

Primaquine (PQ) is the only licensed drug effective against P. vivax for specific hypnozoites and as a key drug in the malaria elimination stage. However, PQ can cause severe hemolysis in G6PD deficient individuals. Unfortunately, few epidemiological data of these disorders was in Indonesia. This study aimed to assesses the prevalence and genotyping variant of G6PDd among the people on malaria-endemic. Blood samples from 555 unrelated subjects in eastern Indonesia were for G6PDd by quantitative test and PCR-RFLP-DNA sequencing. All protocols followed by Promega, Madison, USA. The prevalence of malaria and anemia was 32.6% (181/555) and 16% (89/555) with P. vivaxdominant species 52.5% (95/181), respectively. Overall, 16.6% (92/555) subjects were G6PD deficient, including 58.7% (54/92) females and 41.3% (38/92). Among the 92 cases G6PD deficient molecularly studied, the genotype variant Vanua Lava (T10883C) were detected dominant and unknown G6PD deficient (T-13.154-C) in 3 cases. It was high G6PD deficient in eastern Indonesia indicate that diagnosis and management of G6PD deficient are necessary. Obligatory anti-malaria doses for G6PD deficient individuals, population screening, are needed on endemic malaria in eastern Indonesia.

Nest ectoparasites increase physiological stress in breeding birds: an experiment.

PubMed

Martínez-de la Puente, Josué; Merino, Santiago; Tomás, Gustavo; Moreno, Juan; Morales, Judith; Lobato, Elisa; Martínez, Javier

2011-02-01

Parasites are undoubtedly a biotic factor that produces stress. Heat shock proteins (HSPs) are important molecules buffering cellular damage under adverse conditions. During the breeding season, blue tit Cyanistes caeruleus (L.) adults are affected by blood parasites, nest-dwelling parasites and biting flies, potentially affecting their HSP-mediated responses. Here, we treated females with primaquine to reduce blood parasites and fumigated nests with permethrin to reduce nest-dwelling parasites to test whether these treatments affect HSP60 level during the breeding season. Medicated females, but not controls, had a significant reduction of the intensity of infection by Haemoproteus spp. blood parasites. However, final intensity of infection did not differ significantly between groups, and we did not find an effect of medication on change in HSP60 level. Fumigation reduced the abundance of nest-dwelling parasites (mites, fleas and blowfly larvae) and engorged biting midges in nests. Females breeding in non-fumigated nests increased HSP60 levels during the season more than those breeding in fumigated nests. Furthermore, the change in HSP60 level was positively correlated with the abundance of biting midges. These results show how infections by nest ectoparasites during the breeding period can increase the level of HSPs and suggest that biting midges impose physiological costs on breeding female blue tits. Although plausible, the alternative that biting midges prefer to feed on more stressed birds is poorly supported by previous studies.

Treatment of Pneumocystis jirovecii pneumonia in HIV-infected patients: a review.

PubMed

Huang, Yu-Shan; Yang, Jen-Jia; Lee, Nan-Yao; Chen, Guan-Jhou; Ko, Wen-Chien; Sun, Hsin-Yun; Hung, Chien-Ching

2017-09-01

Pneumocystis pneumonia is a potentially life-threatening pulmonary infection that occurs in immunocompromised individuals and HIV-infected patients with a low CD4 cell count. Trimethoprim-sulfamethoxazole has been used as the first-line agent for treatment, but mutations within dihydropteroate synthase gene render potential resistance to sulfamide. Despite advances of combination antiretroviral therapy (cART), Pneumocystis pneumonia continues to occur in HIV-infected patients with late presentation for cART or virological and immunological failure after receiving cART. Areas covered: This review summarizes the diagnosis and first-line and alternative treatment and prophylaxis for Pneumocystis pneumonia in HIV-infected patients. Articles for this review were identified through searching PubMed. Search terms included: 'Pneumocystis pneumonia', 'Pneumocystis jirovecii pneumonia', 'Pneumocystis carinii pneumonia', 'trimethoprim-sulfamethoxazole', 'primaquine', 'trimetrexate', 'dapsone', 'pentamidine', 'atovaquone', 'echinocandins', 'human immunodeficiency virus infection', 'acquired immunodeficiency syndrome', 'resistance to sulfamide' and combinations of these terms. We limited the search to English language papers that were published between 1981 and March 2017. We screened all identified articles and cross-referenced studies from retrieved articles. Expert commentary: Trimethoprim-sulfamethoxazole will continue to be the first-line agent for Pneumocystis pneumonia given its cost, availability of both oral and parenteral formulations, and effectiveness or efficacy in both treatment and prophylaxis. Whether resistance due to mutations within dihydropteroate synthase gene compromises treatment effectiveness remains controversial. Continued search for effective alternatives with better safety profiles for Pneumocystis pneumonia is warranted.

Plasmodium falciparum and Plasmodium vivax Demonstrate Contrasting Chloroquine Resistance Reversal Phenotypes.

PubMed

Wirjanata, Grennady; Handayuni, Irene; Prayoga, Pak; Leonardo, Leo; Apriyanti, Dwi; Trianty, Leily; Wandosa, Ruland; Gobay, Basbak; Kenangalem, Enny; Poespoprodjo, Jeanne Rini; Noviyanti, Rintis; Kyle, Dennis E; Cheng, Qin; Price, Ric N; Marfurt, Jutta

2017-08-01

High-grade chloroquine (CQ) resistance has emerged in both Plasmodium falciparum and P. vivax The aim of the present study was to investigate the phenotypic differences of CQ resistance in both of these species and the ability of known CQ resistance reversal agents (CQRRAs) to alter CQ susceptibility. Between April 2015 and April 2016, the potential of verapamil (VP), mibefradil (MF), L703,606 (L7), and primaquine (PQ) to reverse CQ resistance was assessed in 46 P. falciparum and 34 P. vivax clinical isolates in Papua, Indonesia, where CQ resistance is present in both species, using a modified schizont maturation assay. In P. falciparum , CQ 50% inhibitory concentrations (IC 50 s) were reduced when CQ was combined with VP (1.4-fold), MF (1.2-fold), L7 (4.2-fold), or PQ (1.8-fold). The degree of CQ resistance reversal in P. falciparum was highly correlated with CQ susceptibility for all CQRRAs ( R 2 = 0.951, 0.852, 0.962, and 0.901 for VP, MF, L7, and PQ, respectively), in line with observations in P. falciparum laboratory strains. In contrast, no reduction in the CQ IC 50 s was observed with any of the CQRRAs in P. vivax , even in those isolates with high chloroquine IC 50 s. The differential effect of CQRRAs in P. falciparum and P. vivax suggests significant differences in CQ kinetics and, potentially, the likely mechanism of CQ resistance between these two species. © Crown copyright 2017.

Malaria chemoprophylaxis with tafenoquine: a randomised study.

PubMed

Lell, B; Faucher, J F; Missinou, M A; Borrmann, S; Dangelmaier, O; Horton, J; Kremsner, P G

2000-06-10

Tafenoquine is an analogue of primaquine with an improved therapeutic and safety profile. It has a long half-life and activity against liver-stage malaria parasites, so may be useful for chemoprophylaxis. In this randomised, double-blind study we assessed the efficacy and safety of tafenoquine in different doses. 2144 individuals aged 12-20 years living in Lambaréné, Gabon, an endemic area for Plasmodium falciparum malaria, were invited to take part. 535 attended, and 426 eligible participants were randomly assigned tafenoquine (250 mg, 125 mg, 62.5 mg, or 31.25 mg) or placebo daily for 3 days. 417 received initial curative treatment with halofantrine, and 410 completed the assigned prophylaxis regimen. During follow-up of 70 days, adverse events were recorded and thick blood smears were examined weekly. The primary and secondary endpoints were the number of individuals with positive blood smears by day 56 and day 77, respectively. Analyses were per-protocol. Eight positive blood smears were recorded by day 56 (four/82 participants in the placebo group; four/79 tafenoquine 31.25 mg group). By day 77, 34 positive blood smears had been recorded (14/82 placebo; 16/79 tafenoquine 31.25 mg; three/86 tafenoquine 62.5 mg; one/79 tafenoquine 125 mg; none/84 tafenoquine 250 mg). Numbers of adverse events did not differ significantly between the treatment groups. Tafenoquine is effective and well tolerated. It has the potential to replace currently used drugs for malaria chemoprophylaxis.

Efficacy and safety of chloroquine for treatment in patients with uncomplicated Plasmodium vivax infections in endemic countries.

PubMed

Naing, Cho; Aung, Kyan; Win, Daw-Khin; Wah, Mak Joon

2010-11-01

Chloroquine (CQ) is a relatively inexpensive drug for treatment of malaria. If efficacy of CQ is still assumed, then it should be indicated in malaria treatment policies as the drug of choice for uncomplicated Plasmodium vivax malaria in endemic countries with resource constraints. The objective of this review is to summarize the existing evidence on the relative efficacy and safety of CQ in treating patients with uncomplicated P. vivax malaria in endemic countries. We searched online data bases (PUBMED, MEDLINE, EMBASE, The Cochrane Library) and the reference lists of the retrieved articles. Fifteen randomized controlled trials (n=6215) assessing the relative efficacy and safety of CQ for treatment of uncomplicated P. vivax malaria were included. CQ monotherapy was compared to CQ plus primaquine (PQ), artemisinin/artemether, artemisinin based combination therapy, quinine, CQ plus tafenoquine, chlorguanil plus dapsone, azithromycin, or placebo. Treatment efficacy was not significantly different between the CQ monotherapy group and that of the CQ with PQ 14 day group at 28 day follow-up (55/711, 7.7% vs 35/712, 4.9%; P=0.16). Evidence from the trials identified for this review draw a fairly clear conclusion about the relative efficacy and safety of CQ for treating uncomplicated P. vivax malaria infection. However, further research in this field with well powered, randomized, non-inferiority design, using the standardized protocol is needed. Copyright © 2010 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

Vitamin D as Supplemental Therapy for Pneumocystis Pneumonia.

PubMed

Lei, Guang-Sheng; Zhang, Chen; Zimmerman, Michelle K; Lee, Chao-Hung

2015-12-14

The combination of all-trans retinoic acid (ATRA) and primaquine (PMQ) has been shown to be effective for therapy of Pneumocystis pneumonia (PCP). Since a high concentration of ATRA has significant adverse effects, the possibility that vitamin D can be used to replace ATRA for PCP therapy was investigated. C57BL/6 mice were immunosuppressed by depleting CD4(+) cells and infected with Pneumocystis murina 1 week after initiation of immunosuppression. Three weeks after infection, the mice were treated orally for 3 weeks with vitamin D3 (VitD3) alone, PMQ alone, a combination of VitD3 and PMQ (VitD3-PMQ), or a combination of trimethoprim and sulfamethoxazole (TMP-SMX). Results showed that VitD3 (300 IU/kg/day) had a synergistic effect with PMQ (5 mg/kg/day) for therapy of PCP. Flow cytometric studies showed that this VitD3-PMQ combination recovered the CD11b(low) CD11c(high) alveolar macrophage population in mice with PCP as effectively as TMP-SMX. The VitD3-PMQ combination also reduced the massive infiltration of inflammatory cells into the lungs and the severity of lung damage. VitD3 was also shown to reduce the dose of TMP-SMX required for effective treatment of PCP. Taken together, results of this study suggest that a VitD3-PMQ combination can be used as an alternative therapy for PCP. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Malaria: prevention in travellers.

PubMed

Croft, Ashley M

2007-11-29

Malaria transmission occurs most frequently in environments with humidity over 60% and ambient temperature of 25-30 degrees C. Risks increase with longer visits and depend on activity. Infection can follow a single mosquito bite. Incubation is usually 10-14 days but can be up to 18 months depending on the strain of parasite. We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of non-drug preventive interventions in adult travellers? What are the effects of drug prophylaxis in adult travellers? What are the effects of antimalaria vaccines in travellers? What are the effects of antimalaria interventions in child travellers, pregnant travellers, and in airline pilots? We searched: Medline, Embase, The Cochrane Library and other important databases up to February 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 69 systematic reviews, RCTs, or observational studies that met our inclusion criteria. In this systematic review we present information relating to the effectiveness and safety of the following interventions: acoustic buzzers, aerosol insecticides, amodiaquine, air conditioning and electric fans, atovaquone-proguanil, biological control measures, chloroquine (alone or with proguanil), diethyltoluamide (DEET), doxycycline, full-length and light-coloured clothing, insecticide-treated clothing/nets, mefloquine, mosquito coils and vaporising mats, primaquine, pyrimethamine-dapsone, pyrimethamine-sulfadoxine, smoke, topical (skin-applied) insect repellents, and vaccines.

Chemoprophylaxis and the epidemiological characteristics of re-emergent P. vivax malaria in the Republic of Korea.

PubMed Central

Kim, Changsoo; Shin, Dong Chun; Yong, Tai Soon; Oh, Dae Kyu; Kim, Rock Kwon; Park, Keeho; Suh, I. L.

2006-01-01

OBJECTIVE: In the Republic of Korea (ROK), soldiers stationed where there is a risk of contracting malaria have received antimalarial chemoprophylaxis since 1997. However, chemoprophylaxis may facilitate the development of drug resistance, and late primary attacks in individuals who have received chemoprophylaxis are becoming more frequent. We investigated the association between chemoprophylaxis and the epidemiological characteristics and effectiveness of treatment for re-emergent Plasmodium vivax malaria, using a nationwide malaria database. METHODS: Among soldiers at risk of malaria between 1999 and 2001, we reviewed all P. vivax malaria cases (1158) that occurred before 31 December 2003. Early and late primary attacks were defined as cases occurring 2 months after the last day of exposure to risk of malaria, respectively. FINDINGS: Of these cases, 634 (72.0%) had received chemoprophylaxis, and 324 (28.0%) had not. Cases occurred mostly in summer, with a peak in July-August. Stratification by chemoprophylaxis history revealed different times to onset. Early primary attacks were more prevalent in the group not receiving chemoprophylaxis, while in the group receiving chemoprophylaxis most cases were late primary attacks. Of the latter, 312 out of 461 (67.7%) did not take primaquine regularly. After treatment of the first attack, 14 (1.2%) of 1158 were re-treated; all re-treated cases were cured using the same doses and regimen used for the first treatment. CONCLUSION: In ROK, the increase in late primary episodes of re-emergent P. vivax malaria is associated with the use of antimalarial chemoprophylaxis. PMID:17128363

Imported malaria in a non-endemic area: the experience of the university of Campinas hospital in the Brazilian Southeast

PubMed Central

2014-01-01

Background Although malaria in Brazil almost exclusively occurs within the boundaries of the Amazon Region, some concerns are raised regarding imported malaria to non-endemic areas of the country, notably increased incidence of complications due to delayed diagnoses. However, although imported malaria in Brazil represents a major health problem, only a few studies have addressed this subject. Methods A retrospective case series is presented in which 263 medical charts were analysed to investigate the clinical and epidemiological characterization of malaria cases that were diagnosed and treated at Hospital & Clinics, State University of Campinas between 1998 and 2011. Results Amongst all medical charts analysed, 224 patients had a parasitological confirmed diagnosis of malaria. Plasmodium vivax and Plasmodium falciparum were responsible for 67% and 30% of the infections, respectively. The majority of patients were male (83%) of a productive age (median, 37 years old). Importantly, severe complications did not differ significantly between P. vivax (14 cases, 9%) and P. falciparum (7 cases, 10%) infections. Conclusions Severe malaria cases were frequent among imported cases in Brazil outside of the Amazon area. The findings reinforce the idea that P. vivax infections in Brazil are not benign, regardless the endemicity of the area studied. Moreover, as the hospital is located in a privileged site, it could be used for future studies of malaria relapses and primaquine resistance mechanisms. Finally, based on the volume of cases treated and the secondary complications, referral malaria services are needed in the non-endemic areas of Brazil for a rapid and efficient and treatment. PMID:25047177

Imported malaria in a non-endemic area: the experience of the university of Campinas hospital in the Brazilian Southeast.

PubMed

Dos-Santos, João C K; Angerami, Rodrigo N; Castiñeiras, Catarina M S; Lopes, Stefanie C P; Albrecht, Letusa; Garcia, Márcia T; Levy, Carlos E; Moretti, Maria L; Lacerda, Marcus V G; Costa, Fabio T M

2014-07-22

Although malaria in Brazil almost exclusively occurs within the boundaries of the Amazon Region, some concerns are raised regarding imported malaria to non-endemic areas of the country, notably increased incidence of complications due to delayed diagnoses. However, although imported malaria in Brazil represents a major health problem, only a few studies have addressed this subject. A retrospective case series is presented in which 263 medical charts were analysed to investigate the clinical and epidemiological characterization of malaria cases that were diagnosed and treated at Hospital & Clinics, State University of Campinas between 1998 and 2011. Amongst all medical charts analysed, 224 patients had a parasitological confirmed diagnosis of malaria. Plasmodium vivax and Plasmodium falciparum were responsible for 67% and 30% of the infections, respectively. The majority of patients were male (83%) of a productive age (median, 37 years old). Importantly, severe complications did not differ significantly between P. vivax (14 cases, 9%) and P. falciparum (7 cases, 10%) infections. Severe malaria cases were frequent among imported cases in Brazil outside of the Amazon area. The findings reinforce the idea that P. vivax infections in Brazil are not benign, regardless the endemicity of the area studied. Moreover, as the hospital is located in a privileged site, it could be used for future studies of malaria relapses and primaquine resistance mechanisms. Finally, based on the volume of cases treated and the secondary complications, referral malaria services are needed in the non-endemic areas of Brazil for a rapid and efficient and treatment.

Antagonism of immunostimulatory CpG-oligodeoxynucleotides by quinacrine, chloroquine, and structurally related compounds.

PubMed

Macfarlane, D E; Manzel, L

1998-02-01

Phosphorothioate oligodeoxynucleotides containing CpG (CpG-ODN) activate immune responses. We report that quinacrine, chloroquine, and structurally related compounds completely inhibit the antiapoptotic effect of CpG-ODN on WEHI 231 murine B lymphoma cells and inhibit CpG-ODN-induced secretion of IL-6 by WEHI 231. They also inhibit IL-6 synthesis and thymidine uptake by human unfractionated PBMC induced by CpG-ODN. The compounds did not inhibit LPS-induced responses. Half-maximal inhibition required 10 nM quinacrine or 100 nM chloroquine. Inhibition was noncompetitive with respect to CpG-ODN. Quinine, quinidine, and primaquine were much less powerful. Quinacrine was effective even when added after the CpG-ODN. Near-toxic concentrations of ammonia plus bafilomycin A1 (used to inhibit vesicular acidification) did not reduce the efficacy of the quinacrine, but the effects of both quinacrine and chloroquine were enhanced by inhibition of the multidrug resistance efflux pump by verapamil. Agents that bind to DNA, including propidium iodide, Hoechst dye 33258, and coralyne chloride did not inhibit CpG-ODN effect, nor did 4-bromophenacyl bromide, an inhibitor of phospholipase A2. Examination of the structure-activity relationship of seventy 4-aminoquinoline and 9-aminoacridine analogues reveals that increased activity was conferred by bulky hydrophobic substituents on positions 2 and 6 of the quinoline nucleus. No correlation was found between published antimalarial activity and ability to block CpG-ODN-induced effects. These results are discussed in the light of the ability of quinacrine and chloroquine to induce remission of rheumatoid arthritis and lupus erythematosus.

Global extent of chloroquine-resistant Plasmodium vivax: a systematic review and meta-analysis

PubMed Central

Price, Ric N; von Seidlein, Lorenz; Valecha, Neena; Nosten, Francois; Baird, J Kevin; White, Nicholas J

2014-01-01

Summary Background Chloroquine is the first-line treatment for Plasmodium vivax malaria in most endemic countries, but resistance is increasing. Monitoring of antimalarial efficacy is essential, but in P vivax infections the assessment of treatment efficacy is confounded by relapse from the dormant liver stages. We systematically reviewed P vivax malaria treatment efficacy studies to establish the global extent of chloroquine resistance. Methods We searched Medline, Web of Science, Embase, and the Cochrane Database of Systematic Reviews to identify studies published in English between Jan 1, 1960, and April 30, 2014, which investigated antimalarial treatment efficacy in P vivax malaria. We excluded studies that did not include supervised schizonticidal treatment without primaquine. We determined rates of chloroquine resistance according to P vivax malaria recurrence rates by day 28 whole-blood chloroquine concentrations at the time of recurrence and study enrolment criteria. Findings We identified 129 eligible clinical trials involving 21 694 patients at 179 study sites and 26 case reports describing 54 patients. Chloroquine resistance was present in 58 (53%) of 113 assessable study sites, spread across most countries that are endemic for P vivax. Clearance of parasitaemia assessed by microscopy in 95% of patients by day 2, or all patients by day 3, was 100% predictive of chloroquine sensitivity. Interpretation Heterogeneity of study design and analysis has confounded global surveillance of chloroquine-resistant P vivax, which is now present across most countries endemic for P vivax. Improved methods for monitoring of drug resistance are needed to inform antimalarial policy in these regions. Funding Wellcome Trust (UK). PMID:25213732

Malaria Chemoprophylaxis: Strategies for Risk Groups

PubMed Central

Schlagenhauf, Patricia; Petersen, Eskild

2008-01-01

The risk of malaria for travelers varies from region to region and depends on the intensity of transmission, the duration of the stay in the area of endemicity, the style of travel, and the efficacy of preventive measures. The decision to recommend chemoprophylaxis to travelers to areas with a low risk of malarial infection is especially difficult because the risk of infection must be balanced with the risk of experiencing side effects. If the risk of side effects by far exceeds the risk of infection, the traveler needs information on measures against mosquito bites and advice on prompt diagnosis and self-treatment. The risk is difficult to quantify, and the absolute risk for travelers to most areas is not known, especially because the populations at risk are unknown. We propose here that the best approximation of the risk to the traveler to a specific area is to use the risk to the indigenous population as a guideline for the risk to the traveler, and we provide examples on how risk in the indigenous population can be used for the estimation of risk of malarial infection for travelers. Special groups are long-term visitors and residents, who often perceive risk differently, cease using chemoprophylaxis, and rely on self-diagnosis and treatment. For long-term visitors, the problem of fake drugs needs to be discussed. Strategies for chemoprophylaxis and self-treatment of pregnant women and small children are discussed. So far, malaria prophylaxis is recommended to prevent Plasmodium falciparum infections, and primaquine prophylaxis against persistent Plasmodium vivax and Plasmodium ovale infections in travelers is not recommended. PMID:18625682

A new primaquine analogue, tafenoquine (WR 238605), for prophylaxis against Plasmodium falciparum malaria.

PubMed

Shanks, G D; Oloo, A J; Aleman, G M; Ohrt, C; Klotz, F W; Braitman, D; Horton, J; Brueckner, R

2001-12-15

We tested tafenoquine (WR 238605), a new long-acting 8-aminoquinoline, for its ability to prevent malaria in an area that is holoendemic for Plasmodium falciparum. In a double-blinded, placebo-controlled, randomized clinical trial in western Kenya, adult volunteers received a treatment course of 250 mg halofantrine per day for 3 days, to effect clearance of preexisting parasites. The volunteers were then assigned to 1 of 4 drug regimens: placebo throughout; 3 days of 400 mg (base) of tafenoquine per day, followed by placebo weekly; 3 days of 200 mg of tafenoquine per day, followed by 200 mg per week; and 3 days of 400 mg of tafenoquine per day, followed by 400 mg per week. Prophylaxis was continued for up to 13 weeks. Of the evaluable subjects (223 of 249 randomized subjects), volunteers who received 400 mg tafenoquine for only 3 days had a protective efficacy of 68% (95% confidence interval [CI], 53%-79%), as compared with placebo recipients; those who received 200 mg per day for 3 days followed by 200 mg per week had a protective efficacy of 86% (95% CI, 73%-93%); and those who received 400 mg for 3 days followed by 400 mg per week had a protective efficacy of 89% (95% CI, 77%-95%). A similar number of volunteers in the 4 treatment groups reported adverse events. Prophylactic regimens of 200 mg or 400 mg of tafenoquine, taken weekly for < or =13 weeks, are highly efficacious in preventing falciparum malaria and are well tolerated.

Drugs in Development for Malaria.

PubMed

Ashley, Elizabeth A; Phyo, Aung Pyae

2018-05-25

The last two decades have seen a surge in antimalarial drug development with product development partnerships taking a leading role. Resistance of Plasmodium falciparum to the artemisinin derivatives, piperaquine and mefloquine in Southeast Asia means new antimalarials are needed with some urgency. There are at least 13 agents in clinical development. Most of these are blood schizonticides for the treatment of uncomplicated falciparum malaria, under evaluation either singly or as part of two-drug combinations. Leading candidates progressing through the pipeline are artefenomel-ferroquine and lumefantrine-KAF156, both in Phase 2b. Treatment of severe malaria continues to rely on two parenteral drugs with ancient forebears: artesunate and quinine, with sevuparin being evaluated as an adjuvant therapy. Tafenoquine is under review by stringent regulatory authorities for approval as a single-dose treatment for Plasmodium vivax relapse prevention. This represents an advance over standard 14-day primaquine regimens; however, the risk of acute haemolytic anaemia in patients with glucose-6-phosphate dehydrogenase deficiency remains. For disease prevention, several of the newer agents show potential but are unlikely to be recommended for use in the main target groups of pregnant women and young children for some years. Latest predictions are that the malaria burden will continue to be high in the coming decades. This fact, coupled with the repeated loss of antimalarials to resistance, indicates that new antimalarials will be needed for years to come. Failure of the artemisinin-based combinations in Southeast Asia has stimulated a reappraisal of current approaches to combination therapy for malaria with incorporation of three or more drugs in a single treatment under consideration.

Randomized, double-blind study of the safety, tolerability, and efficacy of tafenoquine versus mefloquine for malaria prophylaxis in nonimmune subjects.

PubMed

Nasveld, Peter E; Edstein, Michael D; Reid, Mark; Brennan, Leonard; Harris, Ivor E; Kitchener, Scott J; Leggat, Peter A; Pickford, Philip; Kerr, Caron; Ohrt, Colin; Prescott, William

2010-02-01

This study represents the first phase III trial of the safety, tolerability, and effectiveness of tafenoquine for malaria prophylaxis. In a randomized (3:1), double-blinded study, Australian soldiers received weekly malaria prophylaxis with 200 mg tafenoquine (492 subjects) or 250 mg mefloquine (162 subjects) for 6 months on a peacekeeping deployment to East Timor. After returning to Australia, tafenoquine-receiving subjects received a placebo and mefloquine-receiving subjects received 30 mg primaquine daily for 14 days. There were no clinically significant differences between hematological and biochemical parameters of the treatment groups. Treatment-related adverse events for the two groups were similar (tafenoquine, 13.4%; mefloquine, 11.7%). Three subjects on tafenoquine (0.6%) and none on mefloquine discontinued prophylaxis because of possible drug-related adverse events. No diagnoses of malaria occurred for either group during deployment, but 4 cases (0.9%) and 1 case (0.7%) of Plasmodium vivax infection occurred among the tafenoquine and mefloquine groups, respectively, up to 20 weeks after discontinuation of medication. In a subset of subjects recruited for detailed safety assessments, treatment-related mild vortex keratopathy was detected in 93% (69 of 74) of tafenoquine subjects but none of the 21 mefloquine subjects. The vortex keratopathy was not associated with any effect on visual acuity and was fully resolved in all subjects by 1 year. Tafenoquine appears to be safe and well tolerated as malaria prophylaxis. Although the volunteers' precise exposure to malaria could not be proven in this study, tafenoquine appears to be a highly efficacious drug for malaria prophylaxis.

Differential Cytochrome P450 2D Metabolism Alters Tafenoquine Pharmacokinetics

PubMed Central

Vuong, Chau; Xie, Lisa H.; Potter, Brittney M. J.; Zhang, Jing; Zhang, Ping; Duan, Dehui; Nolan, Christina K.; Sciotti, Richard J.; Zottig, Victor E.; Nanayakkara, N. P. Dhammika; Tekwani, Babu L.; Walker, Larry A.; Smith, Philip L.; Paris, Robert M.; Read, Lisa T.; Li, Qigui; Pybus, Brandon S.; Sousa, Jason C.; Reichard, Gregory A.; Smith, Bryan

2015-01-01

Cytochrome P450 (CYP) 2D metabolism is required for the liver-stage antimalarial efficacy of the 8-aminoquinoline molecule tafenoquine in mice. This could be problematic for Plasmodium vivax radical cure, as the human CYP 2D ortholog (2D6) is highly polymorphic. Diminished CYP 2D6 enzyme activity, as in the poor-metabolizer phenotype, could compromise radical curative efficacy in humans. Despite the importance of CYP 2D metabolism for tafenoquine liver-stage efficacy, the exact role that CYP 2D metabolism plays in the metabolism and pharmacokinetics of tafenoquine and other 8-aminoquinoline molecules has not been extensively studied. In this study, a series of tafenoquine pharmacokinetic experiments were conducted in mice with different CYP 2D metabolism statuses, including wild-type (WT) (reflecting extensive metabolizers for CYP 2D6 substrates) and CYPmouse 2D knockout (KO) (reflecting poor metabolizers for CYP 2D6 substrates) mice. Plasma and liver pharmacokinetic profiles from a single 20-mg/kg of body weight dose of tafenoquine differed between the strains; however, the differences were less striking than previous results obtained for primaquine in the same model. Additionally, the presence of a 5,6-ortho-quinone tafenoquine metabolite was examined in both mouse strains. The 5,6-ortho-quinone species of tafenoquine was observed, and concentrations of the metabolite were highest in the WT extensive-metabolizer phenotype. Altogether, this study indicates that CYP 2D metabolism in mice affects tafenoquine pharmacokinetics and could have implications for human tafenoquine pharmacokinetics in polymorphic CYP 2D6 human populations. PMID:25870069

Randomized, Double-Blind Study of the Safety, Tolerability, and Efficacy of Tafenoquine versus Mefloquine for Malaria Prophylaxis in Nonimmune Subjects▿

PubMed Central

Nasveld, Peter E.; Edstein, Michael D.; Reid, Mark; Brennan, Leonard; Harris, Ivor E.; Kitchener, Scott J.; Leggat, Peter A.; Pickford, Philip; Kerr, Caron; Ohrt, Colin; Prescott, William

2010-01-01

This study represents the first phase III trial of the safety, tolerability, and effectiveness of tafenoquine for malaria prophylaxis. In a randomized (3:1), double-blinded study, Australian soldiers received weekly malaria prophylaxis with 200 mg tafenoquine (492 subjects) or 250 mg mefloquine (162 subjects) for 6 months on a peacekeeping deployment to East Timor. After returning to Australia, tafenoquine-receiving subjects received a placebo and mefloquine-receiving subjects received 30 mg primaquine daily for 14 days. There were no clinically significant differences between hematological and biochemical parameters of the treatment groups. Treatment-related adverse events for the two groups were similar (tafenoquine, 13.4%; mefloquine, 11.7%). Three subjects on tafenoquine (0.6%) and none on mefloquine discontinued prophylaxis because of possible drug-related adverse events. No diagnoses of malaria occurred for either group during deployment, but 4 cases (0.9%) and 1 case (0.7%) of Plasmodium vivax infection occurred among the tafenoquine and mefloquine groups, respectively, up to 20 weeks after discontinuation of medication. In a subset of subjects recruited for detailed safety assessments, treatment-related mild vortex keratopathy was detected in 93% (69 of 74) of tafenoquine subjects but none of the 21 mefloquine subjects. The vortex keratopathy was not associated with any effect on visual acuity and was fully resolved in all subjects by 1 year. Tafenoquine appears to be safe and well tolerated as malaria prophylaxis. Although the volunteers' precise exposure to malaria could not be proven in this study, tafenoquine appears to be a highly efficacious drug for malaria prophylaxis. PMID:19995933

Epidemiology of Plasmodium vivax Malaria in Peru

PubMed Central

Rosas-Aguirre, Angel; Gamboa, Dionicia; Manrique, Paulo; Conn, Jan E.; Moreno, Marta; Lescano, Andres G.; Sanchez, Juan F.; Rodriguez, Hugo; Silva, Hermann; Llanos-Cuentas, Alejandro; Vinetz, Joseph M.

2016-01-01

Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s–2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005–2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine–primaquine for P. vivax. Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax. Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination. PMID:27799639

Lysine Acetylation in Sexual Stage Malaria Parasites Is a Target for Antimalarial Small Molecules

PubMed Central

Trenholme, Katharine; Marek, Linda; Duffy, Sandra; Pradel, Gabriele; Fisher, Gillian; Hansen, Finn K.; Skinner-Adams, Tina S.; Butterworth, Alice; Ngwa, Che Julius; Moecking, Jonas; Goodman, Christopher D.; McFadden, Geoffrey I.; Sumanadasa, Subathdrage D. M.; Fairlie, David P.; Avery, Vicky M.

2014-01-01

Therapies to prevent transmission of malaria parasites to the mosquito vector are a vital part of the global malaria elimination agenda. Primaquine is currently the only drug with such activity; however, its use is limited by side effects. The development of transmission-blocking strategies requires an understanding of sexual stage malaria parasite (gametocyte) biology and the identification of new drug leads. Lysine acetylation is an important posttranslational modification involved in regulating eukaryotic gene expression and other essential processes. Interfering with this process with histone deacetylase (HDAC) inhibitors is a validated strategy for cancer and other diseases, including asexual stage malaria parasites. Here we confirm the expression of at least one HDAC protein in Plasmodium falciparum gametocytes and show that histone and nonhistone protein acetylation occurs in this life cycle stage. The activity of the canonical HDAC inhibitors trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA; Vorinostat) and a panel of novel HDAC inhibitors on early/late-stage gametocytes and on gamete formation was examined. Several compounds displayed early/late-stage gametocytocidal activity, with TSA being the most potent (50% inhibitory concentration, 70 to 90 nM). In contrast, no inhibitory activity was observed in P. falciparum gametocyte exflagellation experiments. Gametocytocidal HDAC inhibitors caused hyperacetylation of gametocyte histones, consistent with a mode of action targeting HDAC activity. Our data identify HDAC inhibitors as being among a limited number of compounds that target both asexual and sexual stage malaria parasites, making them a potential new starting point for gametocytocidal drug leads and valuable tools for dissecting gametocyte biology. PMID:24733477

Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in the Ouest and Sud-Est departments of Haiti.

PubMed

von Fricken, Michael E; Weppelmann, Thomas A; Eaton, Will T; Alam, Meer T; Carter, Tamar E; Schick, Laura; Masse, Roseline; Romain, Jean R; Okech, Bernard A

2014-07-01

Malaria remains a significant public health issue in Haiti, with chloroquine (CQ) used almost exclusively for the treatment of uncomplicated infections. Recently, single dose primaquine (PQ) was added to the Haitian national malaria treatment policy, despite a lack of information on the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency within the population. G6PD deficient individuals who take PQ are at risk of developing drug induced hemolysis (DIH). In this first study to examine G6PD deficiency rates in Haiti, 22.8% (range 14.9%-24.7%) of participants were found to be G6PD deficient (class I, II, or III) with 2.0% (16/800) of participants having severe deficiency (class I and II). Differences in deficiency were observed by gender, with males having a much higher prevalence of severe deficiency (4.3% vs. 0.4%) compared to females. Male participants were 1.6 times more likely to be classified as deficient and 10.6 times more likely to be classified as severely deficient compared to females, as expected. Finally, 10.6% (85/800) of the participants were considered to be at risk for DIH. Males also had much higher rates than females (19.3% vs. 4.6%) with 4.9 times greater likelihood (p value 0.000) of having an activity level that could lead to DIH. These findings provide useful information to policymakers and clinicians who are responsible for the implementation of PQ to control and manage malaria in Haiti. Copyright © 2014 Elsevier B.V. All rights reserved.

A new paper-based analytical device for detection of Glucose-6-phosphate dehydrogenase deficiency.

PubMed

Kaewarsa, Phuritat; Laiwattanapaisal, Wanida; Palasuwan, Attakorn; Palasuwan, Duangdao

2017-03-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic haemolytic disorder. Most persons with G6PD deficiency are asymptomatic, but exposure to oxidant drugs, such as the anti-malarial drug primaquine, may induce haemolysis, which is commonly found in Asian countries. A reliable test is necessary for diagnosing the deficiency to prevent an acute haemolytic crisis. This study proposes a novel quantitative method to detect G6PD deficiency using paper-based analytical devices (G6PDD-PAD). Wax printing was utilized for fabricating circular reaction zone patterns in paper. The colorimetric assay is based on the formation of formazan via a reduction of tetra-nitro blue tetrazolium (TNBT) by the G6PD enzyme on G6PDD-PAD. Detection was achieved by capturing the colour using a desktop scanner and the colour intensity was analysed with Adobe Photoshop C56. The results showed that the G6PD activity analysed by G6PDD-PAD was highly correlated with the standard biochemical assay (SBA) (r 2 =0.87, p<0.01). Moreover, good agreement by Bland-Altman bias plot was demonstrated between G6PDD-PAD and the SBA (mean bias 1.4 IU/gHb). The detection limit was 0 IU/gHb of G6PD activity. This study demonstrates the feasibility of using G6PDD-PAD. This simple, low-cost test ($0.1/test) should be useful for diagnosing G6PD deficiency in resource-limited settings. Copyright © 2016 Elsevier B.V. All rights reserved.

Primaquine for reducing Plasmodium falciparum transmission.

PubMed

Graves, Patricia M; Gelband, Hellen; Garner, Paul

2012-09-12

Mosquitoes become infected with malaria when they ingest gametocyte stages of the parasite from the blood of a human host. Plasmodium falciparum gametocytes are sensitive to the drug primaquine (PQ). The World Health Organization (WHO) recommends giving a single dose or short course of PQ alongside primary treatment for people ill with P. falciparum infection to reduce malaria transmission. Gametocytes themselves cause no symptoms, so this intervention does not directly benefit individuals. PQ causes haemolysis in some people with glucose-6-phosphate dehydrogenase (G6PD) deficiency so may not be safe.   To assess whether a single dose or short course of PQ added to treatments for malaria caused by P. falciparum infection reduces malaria transmission and is safe. We searched the following databases up to 10 April 2012 for studies: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; metaRegister of Controlled Trials (mRCT) and the WHO trials search portal using 'malaria*', 'falciparum', and 'primaquine' as search terms. In addition, we searched conference proceedings and reference lists of included studies, and we contacted likely researchers and organizations for relevant trials. Trials of mass treatment of whole populations (or actively detected fever or malaria cases within such populations) with antimalarial drugs, compared to treatment with the same drug plus PQ; or patients with clinical malaria being treated for malaria at health facilities randomized to short course/single dose PQ versus no PQ. Two authors (PMG and HG) independently screened all abstracts, applied inclusion criteria, and abstracted data. We sought data on the effect of PQ on malaria transmission intensity, participant infectiousness, the number of participants with gametocytes, and gametocyte density over time. We stratified results by primary treatment drug as this may modify any PQ effect. We calculated the area under the curve (AUC) for gametocyte density over time for comparisons for which data were available, and also sought data on haematologic and other adverse effects. We used GRADE guidelines to assess evidence quality, and this is reflected in the wording of the results: high quality ("PQ reduces ...."); moderate quality ("PQ probably reduces ..."); low quality ("PQ may reduce...."); and very low quality ("we don't know if PQ reduces...."). We included 11 individually randomized trials, with a total of 1776 individuals. The 11 trials included 20 comparisons with partner drugs, which included chloroquine (CQ), sulfadoxine-pyrimethamine (SP), mefloquine (MQ), quinine (QN), artesunate (AS), and a variety of artemisinin combination therapies (ACTs). For G6PD deficiency, studies either did not test (one study), tested and included all (one study), included only G6PD deficient (one study), excluded G6PD deficient (two studies), or made no comment (six studies).None of the trials we included assessed effects on malaria transmission (incidence, prevalence, or entomological inoculation rate (EIR)) in the trial area.With non-artemisinin drug regimens, PQ may reduce the infectiousness to mosquitoes of individuals treated, based on one small study with large effects (Risk Ratio (RR) 0.06 on day 8 after treatment, 95% confidence interval (CI) 0 to 0.89; low quality evidence). Participants who received PQ had fewer circulating gametocytes up to day 43 (log(10) AUC relative decrease from 24.3 to 27.1%, one study (two comparisons), moderate quality evidence); and there were 38% fewer people with gametocytes on day 8 (RR 0.62, 95% CI 0.51 to 0.76, four studies (five comparisons), moderate quality evidence). We did not identify any study that looked for effects of the drug on haemolytic anaemia.With artemisinin-based drug regimens, we do not know if PQ influences infectiousness to mosquitoes, as no study has examined this directly. PQ probably reduces infectiousness, based on reduction in log(10) AUC (relative decrease range from 26.1% to 87.5%, two studies (six comparisons), moderate quality evidence); and reduces by 88% the number of participants with gametocytes on day 8 (RR 0.12, 95% CI 0.08 to 0.20, four studies (eight comparisons), moderate quality evidence).When used with artemisinin-based regimens, we do not know if PQ results in haemolytic anaemia; one trial reported percent change in mean haemoglobin against baseline, and for the PQ group this indicated a significantly greater drop at day 8 in those given PQ (very low quality evidence). Overall, the safety of PQ used in single dose or short course was poorly evaluated.  We do not know whether PQ added to treatment regimens for patients with P. falciparum infection reduces transmission of malaria. In individual patients, it reduces gametocyte prevalence and density. In practical terms, even if PQ results in large reductions in gametocytes in people being treated for malaria, there is no reliable evidence that this will reduce transmission in a malaria-endemic community, where many people are infected but have no symptoms and are unlikely to be treated. Since PQ is acting as a monotherapy against gametocytes, there is a risk of the parasite developing resistance to the drug. In terms of harms, there is insufficient evidence from trials to know whether the drug can be used safely in this way in populations where G6PD deficiency occurs.In light of these doubts about safety, and lack of evidence of any benefit in reducing transmission, countries should question whether to continue to use PQ routinely in primary treatment of malaria. Further synthesis of observational data on safety and new trials may help elucidate a role for PQ in malaria elimination, or in situations where most infected individuals are symptomatic and receive treatment.

Effect of generalised access to early diagnosis and treatment and targeted mass drug administration on Plasmodium falciparum malaria in Eastern Myanmar: an observational study of a regional elimination programme.

PubMed

Landier, Jordi; Parker, Daniel M; Thu, Aung Myint; Lwin, Khin Maung; Delmas, Gilles; Nosten, François H

2018-05-12

Potentially untreatable Plasmodium falciparum malaria threatens the Greater Mekong subregion. A previous series of pilot projects in Myanmar, Laos, Cambodia, and Vietnam suggested that mass drug administration was safe, and when added to provision of early diagnosis and treatment, could reduce the reservoir of P falciparum and interrupts transmission. We examined the effects of a scaled-up programme of this strategy in four townships of eastern Myanmar on the incidence of P falciparum malaria. The programme was implemented in the four townships of Myawaddy, Kawkareik, Hlaingbwe, and Hpapun in Kayin state, Myanmar. Increased access to early diagnosis and treatment of malaria was provided to all villages through community-based malaria posts equipped with rapid diagnostic tests, and treatment with artemether-lumefantrine plus single low-dose primaquine. Villages were identified as malarial hotspots (operationally defined as >40% malaria, of which 20% was P falciparum) with surveys using ultrasensitive quantitative PCR either randomly or targeted at villages where the incidence of clinical cases of P falciparum malaria remained high (ie, >100 cases per 1000 individuals per year) despite a functioning malaria post. During each survey, a 2 mL sample of venous blood was obtained from randomly selected adults. Hotspots received targeted mass drug administration with dihydroartemisinin-piperaquine plus single-dose primaquine once per month for 3 consecutive months in addition to the malaria posts. The main outcome was the change in village incidence of clinical P falciparum malaria, quantified using a multivariate, generalised, additive multilevel model. Malaria prevalence was measured in the hotspots 12 months after mass drug administration. Between May 1, 2014, and April 30, 2017, 1222 malarial posts were opened, providing early diagnosis and treatment to an estimated 365 000 individuals. Incidence of P falciparum malaria decreased by 60 to 98% in the four townships. 272 prevalence surveys were undertaken and 69 hotspot villages were identified. By April 2017, 50 hotspots were treated with mass drug administration. Hotspot villages had a three times higher incidence of P falciparum at malarial posts than neighbouring villages (adjusted incidence rate ratio [IRR] 2·7, 95% CI 1·8-4·4). Early diagnosis and treatment was associated with a significant decrease in P falciparum incidence in hotspots (IRR 0·82, 95% CI 0·76-0·88 per quarter) and in other villages (0·75, 0·73-0·78 per quarter). Mass drug administration was associated with a five-times decrease in P falciparum incidence within hotspot villages (IRR 0·19, 95% CI 0·13-0·26). By April, 2017, 965 villages (79%) of 1222 corresponding to 104 village tracts were free from P falciparum malaria for at least 6 months. The prevalence of wild-type genotype for K13 molecular markers of artemisinin resistance was stable over the three years (39%; 249/631). Providing early diagnosis and effective treatment substantially decreased village-level incidence of artemisinin-resistant P falciparum malaria in hard-to-reach, politically sensitive regions of eastern Myanmar. Targeted mass drug administration significantly reduced malaria incidence in hotspots. If these activities could proceed in all contiguous endemic areas in addition to standard control programmes already implemented, there is a possibility of subnational elimination of P falciparum. The Bill & Melinda Gates Foundation, the Regional Artemisinin Initiative (Global Fund against AIDS, Tuberculosis and Malaria), and the Wellcome Trust. Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.

Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency among malaria patients in Upper Myanmar.

PubMed

Lee, Jinyoung; Kim, Tae Im; Kang, Jung-Mi; Jun, Hojong; Lê, Hương Giang; Thái, Thị Lam; Sohn, Woon-Mok; Myint, Moe Kyaw; Lin, Khin; Kim, Tong-Soo; Na, Byoung-Kuk

2018-03-16

Glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49) deficiency is one of the most common X-linked recessive hereditary disorders in the world. Primaquine (PQ) has been used for radical cure of P. vivax to prevent relapse. Recently, it is also used to reduce P. falciparum gametocyte carriage to block transmission. However, PQ metabolites oxidize hemoglobin and generate excessive reactive oxygen species which can trigger acute hemolytic anemia in malaria patients with inherited G6PD deficiency. A total of 252 blood samples collected from malaria patients in Myanmar were used in this study. G6PD variant was analysed by a multiplex allele specific PCR kit, DiaPlexC™ G6PD Genotyping Kit [Asian type]. The accuracy of the multiplex allele specific PCR was confirmed by sequencing analysis. Prevalence and distribution of G6PD variants in 252 malaria patients in Myanmar were analysed. Six different types of G6PD allelic variants were identified in 50 (7 females and 43 males) malaria patients. The predominant variant was Mahidol (68%, 34/50), of which 91.2% (31/34) and 8.8% (3/34) were males and females, respectively. Other G6PD variants including Kaiping (18%, 9/50), Viangchan (6%, 3/50), Mediterranean (4%, 2/50), Union (2%, 1/50) and Canton (2%, 1/50) were also observed. Results of this study suggest that more concern for proper and safe use of PQ as a radical cure of malaria in Myanmar is needed by combining G6PD deficiency test before PQ prescription. Establishment of a follow-up system to monitor potential PQ toxicity in malaria patients who are given PQ is also required.

Oxygen consumption in Plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.

PubMed

Deslauriers, R; Moffatt, D J; Smith, I C

1986-05-29

A spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by Plasmodium berghei. The method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. Spectra of intact cells show broad peaks and sloping baselines due to light-scattering. In order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using Fourier transforms of the frequency domain spectra. Calculation of oxygen consumption was carried out for two-component systems (oxyhemoglobin, deoxyhemoglobin) using absorbances at 415 and 431 nm. Samples prepared from highly parasitized mice (greater than 80% parasitemia, 5% hematocrit) showed oxygen consumption rates of (4-8) X 10(-8) microliter/cell per h. This rate was not attributable to the presence of white cells or reticulocytes. The rate of oxygen consumption in the erythrocytes is shown to be modulated by various agents: the respiratory inhibitors NaN3 and KCN (1 mM) reduced oxygen consumption 2-3-fold; salicylhydroxamic acid (2.5 mM) caused a 20% reduction in rate and 10 mM NaN3, completely blocked deoxygenation. Antimalarial drugs and metal-chelating agents were also tested. Chloroquine, EDTA and desferal (desferoxamine mesylate) did not decrease the deoxygenation rate of hemoglobin in parasitized cells. Quinacrine, quinine and primaquine reduced the rate of formation of deoxyhemoglobin but also produced substantial quantities of methemoglobin. The lipophilic chelator, 5-hydroxyquinoline, decreased the rate of deoxygenation one-third. The spectrophotometric assay provides a convenient means to monitor oxygen consumption in parasitized red cells, to test the effects of various agents thereon, and potentially to explore possible mechanisms for oxygen utilization.

G6PD testing in support of treatment and elimination of malaria: recommendations for evaluation of G6PD tests.

PubMed

Domingo, Gonzalo J; Satyagraha, Ari Winasti; Anvikar, Anup; Baird, Kevin; Bancone, Germana; Bansil, Pooja; Carter, Nick; Cheng, Qin; Culpepper, Janice; Eziefula, Chi; Fukuda, Mark; Green, Justin; Hwang, Jimee; Lacerda, Marcus; McGray, Sarah; Menard, Didier; Nosten, Francois; Nuchprayoon, Issarang; Oo, Nwe Nwe; Bualombai, Pongwit; Pumpradit, Wadchara; Qian, Kun; Recht, Judith; Roca, Arantxa; Satimai, Wichai; Sovannaroth, Siv; Vestergaard, Lasse S; Von Seidlein, Lorenz

2013-11-04

Malaria elimination will be possible only with serious attempts to address asymptomatic infection and chronic infection by both Plasmodium falciparum and Plasmodium vivax. Currently available drugs that can completely clear a human of P. vivax (known as "radical cure"), and that can reduce transmission of malaria parasites, are those in the 8-aminoquinoline drug family, such as primaquine. Unfortunately, people with glucose-6-phosphate dehydrogenase (G6PD) deficiency risk having severe adverse reactions if exposed to these drugs at certain doses. G6PD deficiency is the most common human enzyme defect, affecting approximately 400 million people worldwide.Scaling up radical cure regimens will require testing for G6PD deficiency, at two levels: 1) the individual level to ensure safe case management, and 2) the population level to understand the risk in the local population to guide Plasmodium vivax treatment policy. Several technical and operational knowledge gaps must be addressed to expand access to G6PD deficiency testing and to ensure that a patient's G6PD status is known before deciding to administer an 8-aminoquinoline-based drug.In this report from a stakeholder meeting held in Thailand on October 4 and 5, 2012, G6PD testing in support of radical cure is discussed in detail. The focus is on challenges to the development and evaluation of G6PD diagnostic tests, and on challenges related to the operational aspects of implementing G6PD testing in support of radical cure. The report also describes recommendations for evaluation of diagnostic tests for G6PD deficiency in support of radical cure.

Lysine acetylation in sexual stage malaria parasites is a target for antimalarial small molecules.

PubMed

Trenholme, Katharine; Marek, Linda; Duffy, Sandra; Pradel, Gabriele; Fisher, Gillian; Hansen, Finn K; Skinner-Adams, Tina S; Butterworth, Alice; Ngwa, Che Julius; Moecking, Jonas; Goodman, Christopher D; McFadden, Geoffrey I; Sumanadasa, Subathdrage D M; Fairlie, David P; Avery, Vicky M; Kurz, Thomas; Andrews, Katherine T

2014-07-01

Therapies to prevent transmission of malaria parasites to the mosquito vector are a vital part of the global malaria elimination agenda. Primaquine is currently the only drug with such activity; however, its use is limited by side effects. The development of transmission-blocking strategies requires an understanding of sexual stage malaria parasite (gametocyte) biology and the identification of new drug leads. Lysine acetylation is an important posttranslational modification involved in regulating eukaryotic gene expression and other essential processes. Interfering with this process with histone deacetylase (HDAC) inhibitors is a validated strategy for cancer and other diseases, including asexual stage malaria parasites. Here we confirm the expression of at least one HDAC protein in Plasmodium falciparum gametocytes and show that histone and nonhistone protein acetylation occurs in this life cycle stage. The activity of the canonical HDAC inhibitors trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA; Vorinostat) and a panel of novel HDAC inhibitors on early/late-stage gametocytes and on gamete formation was examined. Several compounds displayed early/late-stage gametocytocidal activity, with TSA being the most potent (50% inhibitory concentration, 70 to 90 nM). In contrast, no inhibitory activity was observed in P. falciparum gametocyte exflagellation experiments. Gametocytocidal HDAC inhibitors caused hyperacetylation of gametocyte histones, consistent with a mode of action targeting HDAC activity. Our data identify HDAC inhibitors as being among a limited number of compounds that target both asexual and sexual stage malaria parasites, making them a potential new starting point for gametocytocidal drug leads and valuable tools for dissecting gametocyte biology. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Resistance of infection by Plasmodium vivax to chloroquine in Bolivia.

PubMed

Añez, Arletta; Moscoso, Manuel; Laguna, Ángel; Garnica, Cecilia; Melgar, Viviana; Cuba, Mauren; Gutierrez, Sonia; Ascaso, Carlos

2015-07-01

Chloroquine (CQ) over three days plus primaquine (PQ) for seven days is the treatment of choice of infections by Plasmodium vivax in Bolivia, where 95% of the cases of malaria are attributed to this species. The aim of this study was to evaluate the therapeutic efficacy of CQ in this setting. Patients in the Amazon region of northern Bolivia, were included in the study from May to November 2011 and the therapeutic efficacy of CQ was evaluated over a 28-day follow-up period. Patients with P. vivax mono-infection received 25 mg/Kg body weight of CQ over three days. The concentrations of CQ + desethylchloroquine (DCQ) in blood were determined at days 7 and 28 of follow up; at follow-up and on the day of treatment failure was administered PQ. One hundred patients fulfilled the inclusion criteria, two were lost to follow up and another two were later excluded for protocol violation. Of the 96 patients who completed the follow up 10 showed TF; one presented continued parasitaemia until day 7 of follow up, three on day 21 and six on day 28 of follow up. The geometric mean of CQ + DCQ on day 7 was 321.7 ng/ml (range 197-535 ng/ml). In six patients with TF the CQ + DCQ concentrations in blood on the day of TF were >100 ng/ml. The rate of resistance was 6.5%. The present study demonstrates the presence of resistance to CQ in the treatment of malaria by P. vivax in the Amazon region of Bolivia. New clinical trials are needed to establish alternative treatments against these parasites in this region of South America.

Distribution of Mutations Associated with Antifolate and Chloroquine Resistance among Imported Plasmodium vivax in the State of Qatar.

PubMed

Bansal, Devendra; Acharya, Anushree; Bharti, Praveen K; Abdelraheem, Mohamed H; Elmalik, Ashraf; Abosalah, Salem; Khan, Fahmi Y; ElKhalifa, Mohamed; Kaur, Hargobinder; Mohapatra, Pradyumna K; Sehgal, Rakesh; Idris, Mohammed A; Mahanta, Jagadish; Singh, Neeru; Babiker, Hamza A; Sultan, Ali A

2017-12-01

Plasmodium vivax is the most prevalent parasite worldwide, escalating by spread of drug resistance. Currently, in Qatar, chloroquine (CQ) plus primaquine are recommended for the treatment of P. vivax malaria. The present study examined the prevalence of mutations in dihydrofolate reductase ( dhfr ), dihydropteroate synthase ( dhps ) genes and CQ resistance transporter ( crt-o ) genes, associated with sulphadoxine-pyrimethamine (SP) and chloroquine resistance, among imported P. vivax cases in Qatar. Blood samples were collected from patients positive for P. vivax and seeking medical treatment at Hamad General Hospital, Doha, during 2013-2016. The Sanger sequencing method was performed to examine the single nucleotide polymorphisms in Pvdhfr , Pvdhps , and Pvcrt-o genes. Of 314 examined P. vivax isolates, 247 (78.7%), 294 (93.6%) and 261 (83.1%) were successfully amplified and sequenced for Pvdhfr , Pvdhps , and Pvcrt-o , respectively. Overall, 53.8% ( N = 133) carried mutant alleles (58R/117N) in Pvdhfr , whereas 77.2% ( N = 227) and 90% ( N = 235) isolates possessed wild type allele in Pvdhps and Pvcrt-o genes, respectively. In addition, a total of eleven distinct haplotypes were detected in Pvdhfr / Pvdhps genes. Interestingly, K10 insertion in the Pvcrt-o gene was observed only in patients originating from the Indian subcontinent. The results suggested that CQ remains an acceptable treatment regimen but further clinical data are required to assess the effectiveness of CQ and SP in Qatar to support the current national treatment guidelines. In addition, limited distribution of genetic polymorphisms associated with CQ and SP resistance observed in imported P. vivax infections, necessitates regular monitoring of drug resistant P. vivax malaria in Qatar.

Control of malaria: a successful experience from Viet Nam.

PubMed Central

Hung, Le Q.; Vries, Peter J. de; Giao, Phan T.; Nam, Nguyen V.; Binh, Tran Q.; Chong, M. T.; Quoc, N. T. T. A.; Thanh, T. N.; Hung, L. N.; Kager, P. A.

2002-01-01

OBJECTIVE: To follow malaria prospectively in an ethnic minority commune in the south of Viet Nam with high malaria transmission and seasonal fluctuation, during malaria control interventions using insecticide-treated bednets (ITBNs) and early diagnosis and treatment (EDT) of symptomatic patients. METHODS: From 1994 onwards the following interventions were used: distribution of ITBNs to all households with biannual reimpregnation; construction of a health post and appointment of staff trained in microscopic diagnosis and treatment of malaria; regular supply of materials and drugs; annual cross-sectional malaria surveys with treatment of all parasitaemic subjects, and a programme of community involvement and health education. Surveys were held yearly at the end of the rainy season. During the surveys, demographic data were updated. Diagnosis and treatment of malaria were free of charge. Plasmodium falciparum infection was treated with artesunate and P. vivax infection with chloroquine plus primaquine. FINDINGS: The baseline survey in 1994 recorded 716 inhabitants. Of the children under 2 years of age, 37% were parasitaemic; 56% of children aged 2-10 years, and 35% of the remaining population were parasitaemic. P. falciparum accounted for 73-79% of these infections. The respective splenomegaly rates for the above-mentioned age groups were 20%, 56%, and 32%. In 1999, the proportion of parasitaemic subjects was 4%, 7% and 1%, respectively, of which P.falciparum contributed 56%. The splenomegaly rate was 0%, 5% and 2%, respectively. CONCLUSIONS: A combination of ITBNs and EDT, provided free of charge, complemented by annual diagnosis and treatment during malaria surveys and community involvement with health education successfully brought malaria under control. This approach could be applied to other regions in the south of Viet Nam and provides a sound basis for further studies in other areas with different epidemiological patterns of malaria. PMID:12219158

Differential cytochrome P450 2D metabolism alters tafenoquine pharmacokinetics.

PubMed

Vuong, Chau; Xie, Lisa H; Potter, Brittney M J; Zhang, Jing; Zhang, Ping; Duan, Dehui; Nolan, Christina K; Sciotti, Richard J; Zottig, Victor E; Nanayakkara, N P Dhammika; Tekwani, Babu L; Walker, Larry A; Smith, Philip L; Paris, Robert M; Read, Lisa T; Li, Qigui; Pybus, Brandon S; Sousa, Jason C; Reichard, Gregory A; Smith, Bryan; Marcsisin, Sean R

2015-07-01

Cytochrome P450 (CYP) 2D metabolism is required for the liver-stage antimalarial efficacy of the 8-aminoquinoline molecule tafenoquine in mice. This could be problematic for Plasmodium vivax radical cure, as the human CYP 2D ortholog (2D6) is highly polymorphic. Diminished CYP 2D6 enzyme activity, as in the poor-metabolizer phenotype, could compromise radical curative efficacy in humans. Despite the importance of CYP 2D metabolism for tafenoquine liver-stage efficacy, the exact role that CYP 2D metabolism plays in the metabolism and pharmacokinetics of tafenoquine and other 8-aminoquinoline molecules has not been extensively studied. In this study, a series of tafenoquine pharmacokinetic experiments were conducted in mice with different CYP 2D metabolism statuses, including wild-type (WT) (reflecting extensive metabolizers for CYP 2D6 substrates) and CYPmouse 2D knockout (KO) (reflecting poor metabolizers for CYP 2D6 substrates) mice. Plasma and liver pharmacokinetic profiles from a single 20-mg/kg of body weight dose of tafenoquine differed between the strains; however, the differences were less striking than previous results obtained for primaquine in the same model. Additionally, the presence of a 5,6-ortho-quinone tafenoquine metabolite was examined in both mouse strains. The 5,6-ortho-quinone species of tafenoquine was observed, and concentrations of the metabolite were highest in the WT extensive-metabolizer phenotype. Altogether, this study indicates that CYP 2D metabolism in mice affects tafenoquine pharmacokinetics and could have implications for human tafenoquine pharmacokinetics in polymorphic CYP 2D6 human populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Methods for the field evaluation of quantitative G6PD diagnostics: a review.

PubMed

Ley, Benedikt; Bancone, Germana; von Seidlein, Lorenz; Thriemer, Kamala; Richards, Jack S; Domingo, Gonzalo J; Price, Ric N

2017-09-11

Individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency are at risk of severe haemolysis following the administration of 8-aminoquinoline compounds. Primaquine is the only widely available 8-aminoquinoline for the radical cure of Plasmodium vivax. Tafenoquine is under development with the potential to simplify treatment regimens, but point-of-care (PoC) tests will be needed to provide quantitative measurement of G6PD activity prior to its administration. There is currently a lack of appropriate G6PD PoC tests, but a number of new tests are in development and are likely to enter the market in the coming years. As these are implemented, they will need to be validated in field studies. This article outlines the technical details for the field evaluation of novel quantitative G6PD diagnostics such as sample handling, reference testing and statistical analysis. Field evaluation is based on the comparison of paired samples, including one sample tested by the new assay at point of care and one sample tested by the gold-standard reference method, UV spectrophotometry in an established laboratory. Samples can be collected as capillary or venous blood; the existing literature suggests that potential differences in capillary or venous blood are unlikely to affect results substantially. The collection and storage of samples is critical to ensure preservation of enzyme activity, it is recommended that samples are stored at 4 °C and testing occurs within 4 days of collection. Test results can be visually presented as scatter plot, Bland-Altman plot, and a histogram of the G6PD activity distribution of the study population. Calculating the adjusted male median allows categorizing results according to G6PD activity to calculate standard performance indicators and to perform receiver operating characteristic (ROC) analysis.

Epidemiology of Plasmodium vivax Malaria in Peru.

PubMed

Rosas-Aguirre, Angel; Gamboa, Dionicia; Manrique, Paulo; Conn, Jan E; Moreno, Marta; Lescano, Andres G; Sanchez, Juan F; Rodriguez, Hugo; Silva, Hermann; Llanos-Cuentas, Alejandro; Vinetz, Joseph M

2016-12-28

Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s-2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005-2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine-primaquine for P. vivax Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination. © The American Society of Tropical Medicine and Hygiene.

Chloroquine derivatives block the translocation pores and inhibit cellular entry of Clostridium botulinum C2 toxin and Bacillus anthracis lethal toxin.

PubMed

Kreidler, Anna-Maria; Benz, Roland; Barth, Holger

2017-03-01

The pathogenic bacteria Clostridium botulinum and Bacillus anthracis produce the binary protein toxins C2 and lethal toxin (LT), respectively. These toxins consist of a binding/transport (B 7 ) component that delivers the separate enzyme (A) component into the cytosol of target cells where it modifies its specific substrate and causes cell death. The B 7 components of C2 toxin and LT, C2IIa and PA 63 , respectively, are ring-shaped heptamers that bind to their cellular receptors and form complexes with their A components C2I and lethal factor (LF), respectively. After receptor-mediated endocytosis of the toxin complexes, C2IIa and PA 63 insert into the membranes of acidified endosomes and form trans-membrane pores through which C2I and LF translocate across endosomal membranes into the cytosol. C2IIa and PA 63 also form channels in planar bilayer membranes, and we used this approach earlier to identify chloroquine as a potent blocker of C2IIa and PA 63 pores. Here, a series of chloroquine derivatives was investigated to identify more efficient toxin inhibitors with less toxic side effects. Chloroquine, primaquine, quinacrine, and fluphenazine blocked C2IIa and PA 63 pores in planar lipid bilayers and in membranes of living epithelial cells and macrophages, thereby preventing the pH-dependent membrane transport of the A components into the cytosol and protecting cells from intoxication with C2 toxin and LT. These potent inhibitors of toxin entry underline the central role of the translocation pores for cellular uptake of binary bacterial toxins and as relevant drug targets, and might be lead compounds for novel pharmacological strategies against severe enteric diseases and anthrax.

Genetic determinants of glucose-6-phosphate dehydrogenase activity in Kenya

PubMed Central

2014-01-01

Background The relationship between glucose-6-phosphate dehydrogenase (G6PD) deficiency and clinical phenomena such as primaquine-sensitivity and protection from severe malaria remains poorly defined, with past association studies yielding inconsistent and conflicting results. One possibility is that examination of a single genetic variant might underestimate the presence of true effects in the presence of unrecognized functional allelic diversity. Methods We systematically examined this possibility in Kenya, conducting a fine-mapping association study of erythrocyte G6PD activity in 1828 Kenyan children across 30 polymorphisms at or around the G6PD locus. Results We demonstrate a strong functional role for c.202G>A (rs1050828), which accounts for the majority of variance in enzyme activity observed (P=1.5×10−200, additive model). Additionally, we identify other common variants that exert smaller, intercorrelated effects independent of c.202G>A, and haplotype analyses suggest that each variant tags one of two haplotype motifs that are opposite in sequence identity and effect direction. We posit that these effects are of biological and possible clinical significance, specifically noting that c.376A>G (rs1050829) augments 202AG heterozygote risk for deficiency trait by two-fold (OR = 2.11 [1.12 - 3.84], P=0.014). Conclusions Our results suggest that c.202G>A is responsible for the majority of the observed prevalence of G6PD deficiency trait in Kenya, but also identify a novel role for c.376A>G as a genetic modifier which marks a common haplotype that augments the risk conferred to 202AG heterozygotes, suggesting that variation at both loci merits consideration in genetic association studies probing G6PD deficiency-associated clinical phenotypes. PMID:25201310

Genetic determinants of glucose-6-phosphate dehydrogenase activity in Kenya.

PubMed

Shah, Shivang S; Macharia, Alex; Makale, Johnstone; Uyoga, Sophie; Kivinen, Katja; Craik, Rachel; Hubbart, Christina; Wellems, Thomas E; Rockett, Kirk A; Kwiatkowski, Dominic P; Williams, Thomas N

2014-09-09

The relationship between glucose-6-phosphate dehydrogenase (G6PD) deficiency and clinical phenomena such as primaquine-sensitivity and protection from severe malaria remains poorly defined, with past association studies yielding inconsistent and conflicting results. One possibility is that examination of a single genetic variant might underestimate the presence of true effects in the presence of unrecognized functional allelic diversity. We systematically examined this possibility in Kenya, conducting a fine-mapping association study of erythrocyte G6PD activity in 1828 Kenyan children across 30 polymorphisms at or around the G6PD locus. We demonstrate a strong functional role for c.202G>A (rs1050828), which accounts for the majority of variance in enzyme activity observed (P=1.5×10⁻²⁰⁰, additive model). Additionally, we identify other common variants that exert smaller, intercorrelated effects independent of c.202G>A, and haplotype analyses suggest that each variant tags one of two haplotype motifs that are opposite in sequence identity and effect direction. We posit that these effects are of biological and possible clinical significance, specifically noting that c.376A>G (rs1050829) augments 202AG heterozygote risk for deficiency trait by two-fold (OR = 2.11 [1.12 - 3.84], P=0.014). Our results suggest that c.202G>A is responsible for the majority of the observed prevalence of G6PD deficiency trait in Kenya, but also identify a novel role for c.376A>G as a genetic modifier which marks a common haplotype that augments the risk conferred to 202AG heterozygotes, suggesting that variation at both loci merits consideration in genetic association studies probing G6PD deficiency-associated clinical phenotypes.

Field Trial of the CareStart Biosensor Analyzer for the Determination of Glucose-6-Phosphate Dehydrogenase Activity in Haiti.

PubMed

Weppelmann, Thomas A; von Fricken, Michael E; Wilfong, Tara D; Aguenza, Elisa; Philippe, Taina T; Okech, Bernard A

2017-10-01

Throughout many developing and tropical countries around the world, malaria remains a significant threat to human health. One barrier to malaria elimination is the ability to safely administer primaquine chemotherapy for the radical cure of malaria infections in populations with a high prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency. In the current study, a field trial of the world's first quantitative, point-of-care assay for measuring G6PD activity was conducted in Haiti. The performance of the CareStart Biosensor Analyzer was compared with the gold standard spectrophotometric assay and genotyping of the G6PD allele in schoolchildren ( N = 343) from the Ouest Department of Haiti. In this population, 19.5% of participants (67/343) had some form of G6PD deficiency (< 60% residual activity) and 9.9% (34/343) had moderate-to-severe G6PD deficiency (< 30% residual activity). Overall, 18.95% of participants had the presence of the A-allele (65/343) with 7.87% (27/343) considered at high risk for drug-induced hemolysis (hemizygous males and homozygous females). Compared with the spectrophotometric assay, the sensitivity and specificity to determine participants with < 60% residual activity were 53.7% and 94.6%, respectively; for participants with 30% residual activity, the sensitivity and specificity were 5.9% and 99.7%, respectively. The biosensor overestimated the activity in deficient individuals and underestimated it in participants with normal G6PD activity, indicating the potential for a systematic measurement error. Thus, we suggest that the current version of the biosensor lacks adequate sensitivity and should be improved prior to its use as a point-of-care diagnostic for G6PD deficiency.

A Case of Pneumonia Caused by Pneumocystis jirovecii Resistant to Trimethoprim-Sulfamethoxazole.

PubMed

Lee, Sang Min; Cho, Yong Kyun; Sung, Yon Mi; Chung, Dong Hae; Jeong, Sung Hwan; Park, Jeong-Woong; Lee, Sang Pyo

2015-06-01

A 50-year-old male visited the outpatient clinic and complained of fever, poor oral intake, and weight loss. A chest X-ray demonstrated streaky and fibrotic lesions in both lungs, and chest CT revealed multifocal peribronchial patchy ground-glass opacities with septated cystic lesions in both lungs. Cell counts in the bronchoalveolar lavage fluid revealed lymphocyte-dominant leukocytosis, and further analysis of lymphocyte subsets showed a predominance of cytotoxic T cells and few T helper cells. Video-assisted wedge resection of the left upper lobe was performed, and the histologic examination was indicative of a Pneumocystis jirovecii infection. Trimethoprim-sulfamethoxazole (TMP-SMX) was orally administered for 3 weeks; however, the patient complained of cough, and the pneumonia was aggravated in the follow-up chest X-ray and chest CT. Molecular studies demonstrated mutations at codons 55 and 57 of the dihydropteroate synthase (DHPS) gene, which is associated with the resistance to TMP-SMX. Clindamycin-primaquine was subsequently administered for 3 weeks replacing the TMP-SMX. A follow-up chest X-ray showed that the pneumonia was resolving, and the cough was also alleviated. A positive result of HIV immunoassay and elevated titer of HCV RNA indicated HIV infection as an underlying condition. This case highlights the importance of careful monitoring of patients with P. jirovecii pneumonia (PCP) during the course of treatment, and the molecular study of DHPS mutations. Additionally, altering the anti-PCP drug utilized as treatment must be considered when infection with drug-resistant P. jirovecii is suspected. To the best of our knowledge, this is the first case of TMP-SMX-resistant PCP described in Korea.

Review and drug therapy implications of glucose-6-phosphate dehydrogenase deficiency.

PubMed

Belfield, Kristen D; Tichy, Eric M

2018-02-01

The pathophysiology, diagnosis, and medication-use implications of glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzyme deficiency in humans, are reviewed. Originally identified as favism in patients who experienced hemolysis after ingestion of fava beans, G6PD deficiency results from an X-linked chromosomal mutation that leads to reduced activity of the enzyme responsible for the final step of the pentose phosphate pathway, through which reduced nicotinamide adenine dinucleotide phosphate required for protection of cells from oxidative stress is produced. G6PD deficiency affects about 400 million people worldwide. Diagnosis of G6PD can be made through detection of enzymatic activity (by spectrophotometric testing, fluorescence testing, or formazan-based spot testing) or molecular analysis to detect known mutations of the gene encoding G6PD. Most individuals with G6PD deficiency are asymptomatic throughout life. Symptoms of acute hemolysis associated with G6PD deficiency include anemia, fatigue, back or abdominal pain, jaundice, and hemoglobinuria. The most common precipitators of oxidative stress and hemolysis in G6PD deficiency include medication use and infection. G6PD deficiency should be considered in patients who experience acute hemolysis after exposure to known oxidative medications, infection, or ingestion of fava beans. A diagnosis of G6PD deficiency is most often made through enzymatic activity detection, but molecular analysis may be required in females heterozygous for the disorder. When clinically feasible, rasburicase, primaquine, dapsone, pegloticase, and methylene blue should not be used until a G6PD diagnostic test has been performed. Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Malaria: prevention in travellers.

PubMed

Croft, Ashley M

2010-07-12

Malaria transmission occurs most frequently in environments with humidity greater than 60% and ambient temperature of 25 °C to 30 °C. Risks increase with longer visits and depend on activity. Infection can follow a single mosquito bite. Incubation is usually 10 to 14 days but can be up to 18 months depending on the strain of parasite. We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of non-drug preventive interventions in non-pregnant adult travellers? What are the effects of drug prophylaxis in non-pregnant adult travellers? What are the effects of antimalaria vaccines in adult and child travellers? What are the effects of antimalaria interventions in child travellers, pregnant travellers, and in airline pilots? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 79 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: aerosol insecticides, amodiaquine, air conditioning and electric fans, atovaquone-proguanil, biological control measures, chloroquine (alone or with proguanil), diethyltoluamide (DEET), dietary supplementation, doxycycline, electronic mosquito repellents, full-length and light-coloured clothing, insecticide-treated clothing/nets, mefloquine, mosquito coils and vapourising mats, primaquine, pyrimethamine-dapsone, pyrimethamine-sulfadoxine, smoke, topical (skin-applied) insect repellents, and vaccines.

Primaquine or other 8-aminoquinolines for reducing Plasmodium falciparum transmission.

PubMed

Graves, Patricia M; Choi, Leslie; Gelband, Hellen; Garner, Paul

2018-02-02

The 8-aminoquinoline (8AQ) drugs act on Plasmodium falciparum gametocytes, which transmit malaria from infected people to mosquitoes. In 2012, the World Health Organization (WHO) recommended a single dose of 0.25 mg/kg primaquine (PQ) be added to malaria treatment schedules in low-transmission areas or those with artemisinin resistance. This replaced the previous recommendation of 0.75 mg/kg, aiming to reduce haemolysis risk in people with glucose-6-phosphate dehydrogenase deficiency, common in people living in malarious areas. Whether this approach, and at this dose, is effective in reducing transmission is not clear. To assess the effects of single dose or short-course PQ (or an alternative 8AQ) alongside treatment for people with P. falciparum malaria. We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; and the WHO International Clinical Trials Registry Platform (ICRTP) portal using 'malaria*', 'falciparum', 'primaquine', '8-aminoquinoline', and eight 8AQ drug names as search terms. We checked reference lists of included trials, and contacted researchers and organizations. Date of last search: 21 July 2017. Randomized controlled trials (RCTs) or quasi-RCTs in children or adults, adding PQ (or alternative 8AQ) as a single dose or short course alongside treatment for P. falciparum malaria. Two authors screened abstracts, applied inclusion criteria, and extracted data. We sought evidence on transmission (community incidence), infectiousness (people infectious and mosquitoes infected), and potential infectiousness (gametocyte measures assessed by microscopy or polymerase chain reaction [PCR]). We grouped trials into artemisinin and non-artemisinin treatments, and stratified by PQ dose (low, 0.2 to 0.25 mg/kg; moderate, 0.4 to 0.5 mg/kg; high, 0.75 mg/kg). We used GRADE, and absolute effects of infectiousness using trial control groups. We included 24 RCTs and one quasi-RCT, comprising 43 arms. Fourteen trials evaluated artemisinin treatments (23 arms), nine trials evaluated non-artemisinin treatments (13 arms), and two trials included both artemisinin and non-artemisinin arms (three and two arms, respectively). Two trial arms used bulaquine. Seven PQ arms used low dose (six with artemisinin), 11 arms used moderate dose (seven with artemisinin), and the remaining arms used high dose. Fifteen trials tested for G6PD status: 11 excluded participants with G6PD deficiency, one included only those with G6PD deficiency, and three included all, irrespective of status. The remaining 10 trials either did not test or did not report on testing.No cluster trials evaluating community effects on malaria transmission met the inclusion criteria.With artemisinin treatmentLow dose PQInfectiousness (participants infectious to mosquitoes) was reduced (day 3 or 4: RR 0.12, 95% CI 0.02 to 0.88, 3 trials, 105 participants; day 8: RR 0.34, 95% CI 0.07 to 1.58, 4 trials, 243 participants; low certainty evidence). This translates to a reduction in percentage of people infectious on day 3 or 4 from 14% to 2%, and, for day 8, from 4% to 1%; the waning infectiousness in the control group by day 8 making the absolute effect smaller by day 8. For gametocytes detected by PCR, there was little or no effect of PQ at day 3 or 4 (RR 1.02, 95% CI 0.87 to 1.21; 3 trials, 414 participants; moderate certainty evidence); with reduction at day 8 (RR 0.52, 95% CI 0.41 to 0.65; 4 trials, 532 participants; high certainty evidence). Severe haemolysis was infrequent, with or without PQ, in these groups with few G6PD-deficient individuals (RR 0.98, 95% CI 0.69 to 1.39; 4 trials, 752 participants, moderate certainty evidence).Moderate dose PQInfectiousness was reduced (day 3 or 4: RR 0.13, 95% CI 0.02 to 0.94; 3 trials, 109 participants; day 8 RR 0.33, 95% CI 0.07 to 1.57; 4 trials, 246 participants; low certainty evidence). Illustrative risk estimates for moderate dose were the same as low dose. The pattern and level of certainty of evidence with gametocytes detected by PCR was the same as low dose, and severe haemolysis was infrequent in both groups.High dose PQInfectiousness was reduced (day 4: RR 0.2, 95% CI 0.02 to 1.68, 1 trial, 101 participants; day 8: RR 0.18, 95% CI 0.02 to 1.41, 2 trials, 181 participants, low certainty evidence). The effects on gametocyte prevalence showed a similar pattern to moderate and low dose PQ. Trials did not systematically report evidence of haemolysis.With non-artemisinin treatmentTrials with non-artemisinin treatment have been conducted only for moderate and high dose PQ. With high dose, infectiousness appeared markedly reduced on day 5 (RR 0.09, 95% CI 0.01 to 0.62; 30 participants, very low certainty evidence), with similar reductions at day 8. For both moderate dose (two trials with 221 people) and high dose (two trials with 30 people), reduction in gametocytes (detected by microscopy) showed similar patterns as for artemisinin treatments, with little or no effect at day 4 or 5, and larger effects by day 8. No trials with non-artemisinin partner drugs systematically sought evidence of severe haemolysis.Two trials comparing bulaquine with PQ suggest bulaquine may have larger effects on gametocytes by microscopy on day 8 (RR 0.41, 95% CI 0.26 to 0.66; 2 trials, 112 participants). A single low dose of PQ (0.25 mg/kg) added to artemisinin-based combination therapy for malaria reduces infectiousness of people to mosquitoes at day 3-4 and day 8, and appears as effective as higher doses. The absolute effect is greater at day 3 or 4, and smaller at day 8, in part because of the lower infectiousness in the control group. There was no evidence of increased haemolysis at 0.25 mg/kg, but few G6PD-deficient individuals were included in the trials. The effect on infectiousness precedes the effect of PQ on gametocyte prevalence. We do not know whether single dose PQ could reduce malaria transmission at community level.

Primaquine or other 8-aminoquinoline for reducing Plasmodium falciparum transmission.

PubMed

Graves, Patricia M; Gelband, Hellen; Garner, Paul

2015-02-19

Mosquitoes become infected with Plasmodium when they ingest gametocyte-stage parasites from an infected person's blood. Plasmodium falciparum gametocytes are sensitive to 8-aminoquinolines (8AQ), and consequently these drugs could prevent parasite transmission from infected people to mosquitoes and reduce the incidence of malaria. However, when used in this way, these drugs will not directly benefit the individual.In 2010, the World Health Organization (WHO) recommended a single dose of primaquine (PQ) at 0.75 mg/kg alongside treatment for P. falciparum malaria to reduce transmission in areas approaching malaria elimination. In 2013, the WHO revised this to 0.25 mg/kg to reduce risk of harms in people with G6PD deficiency. To assess the effects of PQ (or an alternative 8AQ) given alongside treatment for P. falciparum malaria on malaria transmission and on the occurrence of adverse events. We searched the following databases up to 5 January 2015: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library (Issue 1, 2015); MEDLINE (1966 to 5 January 2015); EMBASE (1980 to 5 January 2015); LILACS (1982 to 5 January 2015); metaRegister of Controlled Trials (mRCT); and the WHO trials search portal using 'malaria*', 'falciparum', 'primaquine', 8-aminoquinoline and eight individual 8AQ drug names as search terms. In addition, we searched conference proceedings and reference lists of included studies, and contacted researchers and organizations. Randomized controlled trials (RCTs) or quasi-RCTs in children or adults, comparing PQ (or alternative 8AQ) as a single dose or short course alongside treatment for P. falciparum malaria, with the same malaria treatment given without PQ/8AQ. Two review authors independently screened all abstracts, applied inclusion criteria and extracted data. We sought evidence of an impact on transmission (community incidence), infectiousness (mosquitoes infected from humans) and potential infectiousness (gametocyte measures). We calculated the area under the curve (AUC) for gametocyte density over time for comparisons for which data were available. We sought data on haematological and other adverse effects, asexual parasite clearance time and recrudescence. We stratified the analysis by artemisinin and non-artemisinin treatments; and by PQ dose (low < 0.4 mg/kg; medium ≥ 0.4 to < 0.6 mg/kg; high ≥ 0.6 mg/kg). We used the GRADE approach to assess evidence quality. We included 17 RCTs and one quasi-RCT. Eight trials tested for G6PD status: six then excluded participants with G6PD deficiency, one included only those with G6PD deficiency, and one included all irrespective of status. The remaining 10 trials either did not report on whether they tested (eight trials), or reported that they did not test (two trials).Nine trials included study arms with artemisinin-based treatments and eleven included study arms with non-artemisinin-based treatments.Only one trial evaluated PQ given as a single dose of less than 0.4 mg/kg. PQ with artemisinin-based treatments: No trials evaluated effects on malaria transmission directly (incidence, prevalence or entomological inoculation rate) and none evaluated infectiousness to mosquitoes. For potential infectiousness, the proportion of people with detectable gametocytaemia on day eight was reduced by around two-thirds with the high dose PQ category (RR 0.29, 95% confidence interval (CI) 0.22 to 0.37; seven trials, 1380 participants, high quality evidence) and the medium dose PQ category (RR 0.30, 95% CI 0.16 to 0.56; one trial, 219 participants, moderate quality evidence). For the low dose category, the effect size was smaller and the 95% CIs include the possibility of no effect (dose: 0.1 mg/kg: RR 0.67, 95% CI 0.44 to 1.02; one trial, 223 participants, low quality evidence). Reductions in log(10)AUC estimates for gametocytaemia on days 1 to 43 with medium and high doses ranged from 24.3% to 87.5%. For haemolysis, one trial reported percent change in mean haemoglobin against baseline and did not detect a difference between the two arms (very low quality evidence). PQ with non-artemisinin treatments: No trials assessed effects on malaria transmission directly. Two small trials from the same laboratory in China evaluated infectiousness to mosquitoes, and reported that infectivity was eliminated on day 8 in 15/15 patients receiving high dose PQ compared to 1/15 in the control group (low quality evidence). For potential infectiousness, the proportion of people with detectable gametocytaemia on day 8 was reduced by three-fifths with high dose PQ category (RR 0.39, 95% CI 0.25 to 0.62; four trials, 186 participants, high quality evidence), and by around two-fifths with medium dose category (RR 0.60, 95% CI 0.49 to 0.75; one trial, 216 participants, high quality evidence), with no trial in the low dose PQ category reporting this outcome. Reduction in log(10)AUC for gametocytaemia days 1 to 43 were 24.3% and 27.1% for two arms in one trial giving medium dose PQ. No trials systematically sought evidence of haemolysis.Two trials evaluated the 8AQ bulaquine, and suggest the effects may be greater than PQ, but the small number of participants (N = 112) preclude a definite conclusion. In individual patients, PQ added to malaria treatments reduces gametocyte prevalence, but this is based on trials using doses of more than 0.4 mg/kg. Whether this translates into preventing people transmitting malaria to mosquitoes has rarely been tested in controlled trials, but there appeared to be a strong reduction in infectiousness in the two small studies that evaluated this. No included trials evaluated whether this policy has an impact on community malaria transmission.For the currently recommended low dose regimen, there is currently little direct evidence to be confident that the effect of reduction in gametocyte prevalence is preserved, or that it is safe in people with G6PD deficiency.

Primaquine or other 8-aminoquinoline for reducing P. falciparum transmission.

PubMed

Graves, Patricia M; Gelband, Hellen; Garner, Paul

2014-06-30

Mosquitoes become infected with Plasmodium when they ingest gametocyte-stage parasites from an infected person's blood. Plasmodium falciparum gametocytes are sensitive to the drug primaquine (PQ) and other 8-aminoquinolines (8AQ); these drugs could prevent parasite transmission from infected people to mosquitoes, and consequently reduce the incidence of malaria. However, PQ will not directly benefit the individual, and could be harmful to those with glucose-6-phosphate dehydrogenase (G6PD) deficiency.In 2010, The World Health Organization (WHO) recommended a single dose of PQ at 0.75 mg/kg, alongside treatment for P. falciparum malaria to reduce transmission in areas approaching malaria elimination. In 2013 the WHO revised this to 0.25 mg/kg due to concerns about safety. To assess whether giving PQ or an alternative 8AQ alongside treatment for P. falciparum malaria reduces malaria transmission, and to estimate the frequency of severe or haematological adverse events when PQ is given for this purpose. We searched the following databases up to 10 Feb 2014 for trials: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; metaRegister of Controlled Trials (mRCT); and the WHO trials search portal using 'malaria*', 'falciparum', and 'primaquine' as search terms. In addition, we searched conference proceedings and reference lists of included studies, and contacted researchers and organizations. Randomized controlled trials (RCTs) or quasi-RCTs comparing PQ (or alternative 8AQ) given as a single dose or short course alongside treatment for P. falciparum malaria with malaria treatment given without PQ/8AQ in adults or children. Two authors independently screened all abstracts, applied inclusion criteria, and extracted data. We sought evidence of an impact on transmission (community incidence), infectiousness (mosquitoes infected from humans) and potential infectiousness (gametocyte measures). We calculated the area under the curve (AUC) for gametocyte density over time for comparisons for which data were available. We sought data on haematological and other adverse effects, as well as secondary outcomes of asexual clearance time and recrudescence. We stratified by whether the malaria treatment regimen included an artemisinin derivative or not; by PQ dose category (low < 0.4 mg/kg; medium ≥ 0.4 to < 0.6 mg/kg; high ≥ 0.6 mg/kg); and by PQ schedules. We used the GRADE approach to assess evidence quality. We included 17 RCTs and one quasi-RCT. Eight studies tested for G6PD status: six then excluded participants with G6PD deficiency, one included only those with G6PD deficiency, and one included all irrespective of status. The remaining ten trials either did not report on whether they tested (8), or reported that they did not test (2). Nine trials included study arms with artemisinin-based malaria treatment regimens, and eleven included study arms with non-artemisinin-based treatments.Only two trials evaluated PQ given at low doses (0.25 mg/kg in one and 0.1 mg/kg in the other). PQ with artemisinin-based treatments: No trials evaluated effects on malaria transmission directly (incidence, prevalence, or entomological inoculation rate), and none evaluated infectiousness to mosquitoes. For potential infectiousness, the proportion of people with detectable gametocytaemia on day eight was reduced by around two thirds with high dose PQ category (RR 0.29, 95% CI 0.22 to 0.37, seven trials, 1380 participants, high quality evidence), and with medium dose PQ category (RR 0.34, 95% CI 0.19 to 0.59, two trials, 269 participants, high quality evidence), but the trial evaluating low dose PQ category (0.1 mg/kg) did not demonstrate an effect (RR 0.67, 95% CI 0.44 to 1.02, one trial, 223 participants, low quality evidence). Reductions in log(10)AUC estimates for gametocytaemia on days 1 to 43 with medium and high doses ranged from 24.3% to 87.5%. For haemolysis, one trial reported percent change in mean haemoglobin against baseline, and did not detect a difference between the two arms (very low quality evidence). PQ with non-artemisinin treatments: No trials assessed effects on malaria transmission directly. Two small trials from the same laboratory evaluated infectiousness to mosquitoes, and report that infectivity was eliminated on day 8 in 15/15 patients receiving high dose PQ compared to 1/15 in the control group (low quality evidence). For potential infectiousness, the proportion of people with detectable gametocytaemia on day 8 was reduced by around half with high dose PQ category (RR 0.44, 95% CI 0.27 to 0.70, three trials, 206 participants, high quality evidence), and by around a third with medium dose category (RR 0.62, 0.50 to 0.76, two trials, 283 participants, high quality evidence), but the single trial using low dose PQ category did not demonstrate a difference between groups (one trial, 59 participants, very low quality evidence). Reduction in log(10)AUC for gametocytaemia days 1 to 43 were 24.3% and 27.1% for two arms in one trial giving medium dose PQ. No trials systematically sought evidence of haemolysis.Two trials evaluated the 8AQ bulaquine, and suggest the effects may be greater than PQ, but the small number of participants (n = 112) preclude a definite conclusion. In individual patients, PQ added to malaria treatments reduces gametocyte prevalence when given in doses greater than 0.4 mg/kg. Whether this translates into preventing people transmitting malaria to mosquitoes has rarely been tested in controlled trials, but there appeared to be a strong reduction in infectiousness in the two small studies that evaluated this. No included trials evaluated whether this policy has an impact on community malaria transmission either in low-endemic settings approaching elimination, or in highly-endemic settings where many people are infected but have no symptoms and are unlikely to be treated.For the currently recommended low dose regimen, there is little direct evidence to be confident that the effect of reduction in gametocyte prevalence is preserved.Most trials excluded people with G6PD deficiency, and thus there is little reliable evidence from controlled trials of the safety of PQ in single dose or short course.

Efficacy of Artesunate-mefloquine for Chloroquine-resistant Plasmodium vivax Malaria in Malaysia: An Open-label, Randomized, Controlled Trial

PubMed Central

Grigg, Matthew J.; William, Timothy; Menon, Jayaram; Barber, Bridget E.; Wilkes, Christopher S.; Rajahram, Giri S.; Edstein, Michael D.; Auburn, Sarah; Price, Ric N.; Yeo, Tsin W.; Anstey, Nicholas M.

2016-01-01

Background. Chloroquine (CQ)-resistant Plasmodium vivax is increasingly reported throughout southeast Asia. The efficacy of CQ and alternative artemisinin combination therapies (ACTs) for vivax malaria in Malaysia is unknown. Methods. A randomized, controlled trial of CQ vs artesunate-mefloquine (AS-MQ) for uncomplicated vivax malaria was conducted in 3 district hospitals in Sabah, Malaysia. Primaquine was administered on day 28. The primary outcome was the cumulative risk of treatment failure by day 28 by Kaplan–Meier analysis. Results. From 2012 to 2014, 103 adults and children were enrolled. Treatment failure by day 28 was 61.1% (95% confidence interval [CI], 46.8–75.6) after CQ and 0% (95% CI, 0–.08) following AS-MQ (P < .001), of which 8.2% (95% CI, 2.5–9.6) were early treatment failures. All patients with treatment failure had therapeutic plasma CQ concentrations at day 7. Compared with CQ, AS-MQ was associated with faster parasite clearance (normalized clearance slope, 0.311 vs 0.127; P < .001) and fever clearance (mean, 19.0 vs 37.7 hours; P = .001) and with lower risk of anemia at day 28 (odds ratio = 3.7; 95% CI, 1.5–9.3; P = .005). Gametocytes were present at day 28 in 23.8% (10/42) of patients following CQ vs none with AS-MQ (P < .001). AS-MQ resulted in lower bed occupancy: 4037 vs 6510 days/1000 patients (incidence rate ratio 0.62; 95% CI, .60–.65; P < .001). One patient developed severe anemia not regarded as related to their AS-MQ treatment. Conclusions. High-grade CQ-resistant P. vivax is prevalent in eastern Malaysia. AS-MQ is an efficacious ACT for all malaria species. Wider CQ-efficacy surveillance is needed in vivax-endemic regions with earlier replacement with ACT when treatment failure is detected. Clinical Trials Registration. NCT01708876. PMID:27107287

Efficacy of Artesunate-mefloquine for Chloroquine-resistant Plasmodium vivax Malaria in Malaysia: An Open-label, Randomized, Controlled Trial.

PubMed

Grigg, Matthew J; William, Timothy; Menon, Jayaram; Barber, Bridget E; Wilkes, Christopher S; Rajahram, Giri S; Edstein, Michael D; Auburn, Sarah; Price, Ric N; Yeo, Tsin W; Anstey, Nicholas M

2016-06-01

Chloroquine (CQ)-resistant Plasmodium vivax is increasingly reported throughout southeast Asia. The efficacy of CQ and alternative artemisinin combination therapies (ACTs) for vivax malaria in Malaysia is unknown. A randomized, controlled trial of CQ vs artesunate-mefloquine (AS-MQ) for uncomplicated vivax malaria was conducted in 3 district hospitals in Sabah, Malaysia. Primaquine was administered on day 28. The primary outcome was the cumulative risk of treatment failure by day 28 by Kaplan-Meier analysis. From 2012 to 2014, 103 adults and children were enrolled. Treatment failure by day 28 was 61.1% (95% confidence interval [CI], 46.8-75.6) after CQ and 0% (95% CI, 0-.08) following AS-MQ (P < .001), of which 8.2% (95% CI, 2.5-9.6) were early treatment failures. All patients with treatment failure had therapeutic plasma CQ concentrations at day 7. Compared with CQ, AS-MQ was associated with faster parasite clearance (normalized clearance slope, 0.311 vs 0.127; P < .001) and fever clearance (mean, 19.0 vs 37.7 hours; P =001) and with lower risk of anemia at day 28 (odds ratio = 3.7; 95% CI, 1.5-9.3; P =005). Gametocytes were present at day 28 in 23.8% (10/42) of patients following CQ vs none with AS-MQ (P < .001). AS-MQ resulted in lower bed occupancy: 4037 vs 6510 days/1000 patients (incidence rate ratio 0.62; 95% CI, .60-.65; P < .001). One patient developed severe anemia not regarded as related to their AS-MQ treatment. High-grade CQ-resistant P. vivax is prevalent in eastern Malaysia. AS-MQ is an efficacious ACT for all malaria species. Wider CQ-efficacy surveillance is needed in vivax-endemic regions with earlier replacement with ACT when treatment failure is detected.Clinical Trials Registration NCT01708876. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

Drug resistance associated genetic polymorphisms in Plasmodium falciparum and Plasmodium vivax collected in Honduras, Central America.

PubMed

Jovel, Irina T; Mejía, Rosa E; Banegas, Engels; Piedade, Rita; Alger, Jackeline; Fontecha, Gustavo; Ferreira, Pedro E; Veiga, Maria I; Enamorado, Irma G; Bjorkman, Anders; Ursing, Johan

2011-12-19

In Honduras, chloroquine and primaquine are recommended and still appear to be effective for treatment of Plasmodium falciparum and Plasmodium vivax malaria. The aim of this study was to determine the proportion of resistance associated genetic polymorphisms in P. falciparum and P. vivax collected in Honduras. Blood samples were collected from patients seeking medical attention at the Hospital Escuela in Tegucigalpa from 2004 to 2006 as well as three regional hospitals, two health centres and one regional laboratory during 2009. Single nucleotide polymorphisms in P. falciparum chloroquine resistance transporter (pfcrt), multidrug resistance 1 (pfmdr1), dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes and in P. vivax multidrug resistance 1 (pvmdr1) and dihydrofolate reductase (pvdhfr) genes were detected using PCR based methods. Thirty seven P. falciparum and 64 P. vivax samples were collected. All P. falciparum infections acquired in Honduras carried pfcrt, pfmdr1, pfdhps and pfdhfr alleles associated with chloroquine, amodiaquine and sulphadoxine-pyrimethamine sensitivity only. One patient with parasites acquired on a Pacific Island had pfcrt 76 T and pfmdr1 86Y alleles. That patient and a patient infected in West Africa had pfdhfr 51I, 59 R and 108 N alleles. Pvmdr1 976 F was found in 7/37 and two copies of pvmdr1 were found in 1/37 samples. Pvdhfr 57 L + 58 R was observed in 2/57 samples. The results indicate that P. falciparum from Honduras remain sensitive to chloroquine and sulphadoxine-pyrimethamine. This suggests that chloroquine and sulphadoxine-pyrimethamine should be efficacious for treatment of uncomplicated P. falciparum malaria, supporting current national treatment guidelines. However, genetic polymorphisms associated with chloroquine and sulphadoxine-pyrimethamine tolerance were detected in local P. vivax and imported P. falciparum infections. Continuous monitoring of the prevalence of drug resistant/tolerant P. falciparum and P. vivax is therefore essential also in Honduras.

Drug resistance associated genetic polymorphisms in Plasmodium falciparum and Plasmodium vivax collected in Honduras, Central America

PubMed Central

2011-01-01

Background In Honduras, chloroquine and primaquine are recommended and still appear to be effective for treatment of Plasmodium falciparum and Plasmodium vivax malaria. The aim of this study was to determine the proportion of resistance associated genetic polymorphisms in P. falciparum and P. vivax collected in Honduras. Methods Blood samples were collected from patients seeking medical attention at the Hospital Escuela in Tegucigalpa from 2004 to 2006 as well as three regional hospitals, two health centres and one regional laboratory during 2009. Single nucleotide polymorphisms in P. falciparum chloroquine resistance transporter (pfcrt), multidrug resistance 1 (pfmdr1), dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes and in P. vivax multidrug resistance 1 (pvmdr1) and dihydrofolate reductase (pvdhfr) genes were detected using PCR based methods. Results Thirty seven P. falciparum and 64 P. vivax samples were collected. All P. falciparum infections acquired in Honduras carried pfcrt, pfmdr1, pfdhps and pfdhfr alleles associated with chloroquine, amodiaquine and sulphadoxine-pyrimethamine sensitivity only. One patient with parasites acquired on a Pacific Island had pfcrt 76 T and pfmdr1 86Y alleles. That patient and a patient infected in West Africa had pfdhfr 51I, 59 R and 108 N alleles. Pvmdr1 976 F was found in 7/37 and two copies of pvmdr1 were found in 1/37 samples. Pvdhfr 57 L + 58 R was observed in 2/57 samples. Conclusion The results indicate that P. falciparum from Honduras remain sensitive to chloroquine and sulphadoxine-pyrimethamine. This suggests that chloroquine and sulphadoxine-pyrimethamine should be efficacious for treatment of uncomplicated P. falciparum malaria, supporting current national treatment guidelines. However, genetic polymorphisms associated with chloroquine and sulphadoxine-pyrimethamine tolerance were detected in local P. vivax and imported P. falciparum infections. Continuous monitoring of the prevalence of drug resistant/tolerant P. falciparum and P. vivax is therefore essential also in Honduras. PMID:22183028

The Importance of Blood Is Infinite: Conceptions of Blood as Life Force, Rumours and Fear of Trial Participation in a Fulani Village in Rural Gambia.

PubMed

O'Neill, Sarah; Dierickx, Susan; Okebe, Joseph; Dabira, Edgard; Gryseels, Charlotte; d'Alessandro, Umberto; Peeters Grietens, Koen

2016-01-01

Clinical trials require high levels of participation and low drop-out rates to be successful. However, collecting blood samples from individuals recruited into clinical trials can be challenging when there is reticence about blood-taking. In addition to concerns regarding the feasibility of medical research, fears of 'blood-stealing' and 'blood-selling' have ethical implications related to cultural sensitivity and informed consent. This study explores anxieties around blood-taking during a malaria treatment trial in the Gambia. This case study is based on ethnographic research in one theoretically selected village due to the high reticence to screening for the clinical trial 'Primaquine's gametocytocidal efficacy in malaria asymptomatic carriers treated with dihydroartemisinin-piperaquine' carried out in the Gambia between 2013 and 2014. Data collection tools included in-depth interviews, participant observation, informal conversations and group discussions. In total only 176 of 411 habitants (42%) in the village accepted having a bloodspot taken to screen for malaria. Although trial recruitment was initially high in the village, some families refused screening when rumours started spreading that the trial team was taking too much blood. Concerns about 'loss of blood' were equated to loss of strength and lack of good food to replenish bodily forces. Families in the study village were concerned about the weakness of their body while they had to harvest their crops at the time of recruitment for the trial. A common recommendation to prevent and avoid rumours against public health interventions and trials is the provision of full and consistent information during the consent procedure, which is assumed to lead to more accurate knowledge of the purpose of the intervention and increased trial participation. However, even when information provision is continuous, the emergence of rumours can be related to times of uncertainty and perceptions of vulnerability, which are often a reflection of structural inequalities and diverging value orientations between communities and public health institutions.

Simple Real-Time PCR and Amplicon Sequencing Method for Identification of Plasmodium Species in Human Whole Blood.

PubMed

Lefterova, Martina I; Budvytiene, Indre; Sandlund, Johanna; Färnert, Anna; Banaei, Niaz

2015-07-01

Malaria is the leading identifiable cause of fever in returning travelers. Accurate Plasmodium species identification has therapy implications for P. vivax and P. ovale, which have dormant liver stages requiring primaquine. Compared to microscopy, nucleic acid tests have improved specificity for species identification and higher sensitivity for mixed infections. Here, we describe a SYBR green-based real-time PCR assay for Plasmodium species identification from whole blood, which uses a panel of reactions to detect species-specific non-18S rRNA gene targets. A pan-Plasmodium 18S rRNA target is also amplified to allow species identification or confirmation by sequencing if necessary. An evaluation of assay accuracy, performed on 76 clinical samples (56 positives using thin smear microscopy as the reference method and 20 negatives), demonstrated clinical sensitivities of 95.2% for P. falciparum (20/21 positives detected) and 100% for the Plasmodium genus (52/52), P. vivax (20/20), P. ovale (9/9), and P. malariae (6/6). The sensitivity of the P. knowlesi-specific PCR was evaluated using spiked whole blood samples (100% [10/10 detected]). The specificities of the real-time PCR primers were 94.2% for P. vivax (49/52) and 100% for P. falciparum (51/51), P. ovale (62/62), P. malariae (69/69), and P. knowlesi (52/52). Thirty-three specimens were used to test species identification by sequencing the pan-Plasmodium 18S rRNA PCR product, with correct identification in all cases. The real-time PCR assay also identified two samples with mixed P. falciparum and P. ovale infection, which was confirmed by sequencing. The assay described here can be integrated into a malaria testing algorithm in low-prevalence areas, allowing definitive Plasmodium species identification shortly after malaria diagnosis by microscopy. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Evaluation of the diagnostic accuracy of CareStart G6PD deficiency Rapid Diagnostic Test (RDT) in a malaria endemic area in Ghana, Africa.

PubMed

Adu-Gyasi, Dennis; Asante, Kwaku Poku; Newton, Sam; Dosoo, David; Amoako, Sabastina; Adjei, George; Amoako, Nicholas; Ankrah, Love; Tchum, Samuel Kofi; Mahama, Emmanuel; Agyemang, Veronica; Kayan, Kingsley; Owusu-Agyei, Seth

2015-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most widespread enzyme defect that can result in red cell breakdown under oxidative stress when exposed to certain medicines including antimalarials. We evaluated the diagnostic accuracy of CareStart G6PD deficiency Rapid Diagnostic Test (RDT) as a point-of-care tool for screening G6PD deficiency. A cross-sectional study was conducted among 206 randomly selected and consented participants from a group with known G6PD deficiency status between February 2013 and June 2013. A maximum of 1.6ml of capillary blood samples were used for G6PD deficiency screening using CareStart G6PD RDT and Trinity qualitative with Trinity quantitative methods as the "gold standard". Samples were also screened for the presence of malaria parasites. Data entry and analysis were done using Microsoft Access 2010 and Stata Software version 12. Kintampo Health Research Centre Institutional Ethics Committee granted ethical approval. The sensitivity (SE) and specificity (SP) of CareStart G6PD deficiency RDT was 100% and 72.1% compared to Trinity quantitative method respectively and was 98.9% and 96.2% compared to Trinity qualitative method. Malaria infection status had no significant (P=0.199) change on the performance of the G6PD RDT test kit compared to the "gold standard". The outcome of this study suggests that the diagnostic performance of the CareStart G6PD deficiency RDT kit was high and it is acceptable at determining the G6PD deficiency status in a high malaria endemic area in Ghana. The RDT kit presents as an attractive tool for point-of-care G6PD deficiency for rapid testing in areas with high temperatures and less expertise. The CareStart G6PD deficiency RDT kit could be used to screen malaria patients before administration of the fixed dose primaquine with artemisinin-based combination therapy.

Confirmed Plasmodium vivax Resistance to Chloroquine in Central Vietnam.

PubMed

Thanh, Pham Vinh; Hong, Nguyen Van; Van, Nguyen Van; Louisa, Melva; Baird, Kevin; Xa, Nguyen Xuan; Peeters Grietens, Koen; Hung, Le Xuan; Duong, Tran Thanh; Rosanas-Urgell, Anna; Speybroeck, Niko; D'Alessandro, Umberto; Erhart, Annette

2015-12-01

Plasmodium vivax resistance to chloroquine (CQ) is currently reported in almost all countries where P. vivax is endemic. In Vietnam, despite a first report on P. vivax resistance to chloroquine published in the early 2000s, P. vivax was still considered sensitive to CQ. Between May 2009 and December 2011, a 2-year cohort study was conducted in central Vietnam to assess the recommended radical cure regimen based on a 10-day course of primaquine (0.5 mg/kg/day) together with 3 days of CQ (25 mg/kg). Here we report the results of the first 28-day follow-up estimating the cumulative risk of P. vivax recurrences together with the corresponding CQ blood concentrations, among other endpoints. Out of 260 recruited P. vivax patients, 240 completed treatment and were followed up to day 28 according to the WHO guidelines. Eight patients (3.45%) had a recurrent P. vivax infection, at day 14 (n = 2), day 21 (n = 1), and day 28 (n = 5). Chloroquine blood concentrations, available for 3/8 recurrent infections (days 14, 21, and 28), were above the MIC (>100 ng/ml whole blood) in all of these cases. Fever and parasitemia (both sexual and asexual stages) were cleared by day 3. Anemia was common at day 0 (35.8%), especially in children under 10 years (50%), and hemoglobin (Hb) recovery at day 28 was substantial among anemic patients (median change from day 0 to 28, +1.7 g/dl; interquartile range [IQR], +0.7 to +3.2). This report, based on CQ blood levels measured at the time of recurrences, confirms for the first time P. vivax CQ resistance in central Vietnam and calls for further studies using standardized protocols for accurately monitoring the extent and evolution of P. vivax resistance to chloroquine in Vietnam. These results, together with the mounting evidence of artemisinin resistance in central Vietnam, further highlight the increasing threat of antimalarial drug resistance to malaria elimination in Vietnam. Copyright © 2015 Thanh et al.

Visualisation and quantitative analysis of the rodent malaria liver stage by real time imaging.

PubMed

Ploemen, Ivo H J; Prudêncio, Miguel; Douradinha, Bruno G; Ramesar, Jai; Fonager, Jannik; van Gemert, Geert-Jan; Luty, Adrian J F; Hermsen, Cornelus C; Sauerwein, Robert W; Baptista, Fernanda G; Mota, Maria M; Waters, Andrew P; Que, Ivo; Lowik, Clemens W G M; Khan, Shahid M; Janse, Chris J; Franke-Fayard, Blandine M D

2009-11-18

The quantitative analysis of Plasmodium development in the liver in laboratory animals in cultured cells is hampered by low parasite infection rates and the complicated methods required to monitor intracellular development. As a consequence, this important phase of the parasite's life cycle has been poorly studied compared to blood stages, for example in screening anti-malarial drugs. Here we report the use of a transgenic P. berghei parasite, PbGFP-Luc(con), expressing the bioluminescent reporter protein luciferase to visualize and quantify parasite development in liver cells both in culture and in live mice using real-time luminescence imaging. The reporter-parasite based quantification in cultured hepatocytes by real-time imaging or using a microplate reader correlates very well with established quantitative RT-PCR methods. For the first time the liver stage of Plasmodium is visualized in whole bodies of live mice and we were able to discriminate as few as 1-5 infected hepatocytes per liver in mice using 2D-imaging and to identify individual infected hepatocytes by 3D-imaging. The analysis of liver infections by whole body imaging shows a good correlation with quantitative RT-PCR analysis of extracted livers. The luminescence-based analysis of the effects of various drugs on in vitro hepatocyte infection shows that this method can effectively be used for in vitro screening of compounds targeting Plasmodium liver stages. Furthermore, by analysing the effect of primaquine and tafenoquine in vivo we demonstrate the applicability of real time imaging to assess parasite drug sensitivity in the liver. The simplicity and speed of quantitative analysis of liver-stage development by real-time imaging compared to the PCR methodologies, as well as the possibility to analyse liver development in live mice without surgery, opens up new possibilities for research on Plasmodium liver infections and for validating the effect of drugs and vaccines on the liver stage of Plasmodium.

Visualisation and Quantitative Analysis of the Rodent Malaria Liver Stage by Real Time Imaging

PubMed Central

Douradinha, Bruno G.; Ramesar, Jai; Fonager, Jannik; van Gemert, Geert-Jan; Luty, Adrian J. F.; Hermsen, Cornelus C.; Sauerwein, Robert W.; Baptista, Fernanda G.; Mota, Maria M.; Waters, Andrew P.; Que, Ivo; Lowik, Clemens W. G. M.; Khan, Shahid M.; Janse, Chris J.; Franke-Fayard, Blandine M. D.

2009-01-01

The quantitative analysis of Plasmodium development in the liver in laboratory animals in cultured cells is hampered by low parasite infection rates and the complicated methods required to monitor intracellular development. As a consequence, this important phase of the parasite's life cycle has been poorly studied compared to blood stages, for example in screening anti-malarial drugs. Here we report the use of a transgenic P. berghei parasite, PbGFP-Luccon, expressing the bioluminescent reporter protein luciferase to visualize and quantify parasite development in liver cells both in culture and in live mice using real-time luminescence imaging. The reporter-parasite based quantification in cultured hepatocytes by real-time imaging or using a microplate reader correlates very well with established quantitative RT-PCR methods. For the first time the liver stage of Plasmodium is visualized in whole bodies of live mice and we were able to discriminate as few as 1–5 infected hepatocytes per liver in mice using 2D-imaging and to identify individual infected hepatocytes by 3D-imaging. The analysis of liver infections by whole body imaging shows a good correlation with quantitative RT-PCR analysis of extracted livers. The luminescence-based analysis of the effects of various drugs on in vitro hepatocyte infection shows that this method can effectively be used for in vitro screening of compounds targeting Plasmodium liver stages. Furthermore, by analysing the effect of primaquine and tafenoquine in vivo we demonstrate the applicability of real time imaging to assess parasite drug sensitivity in the liver. The simplicity and speed of quantitative analysis of liver-stage development by real-time imaging compared to the PCR methodologies, as well as the possibility to analyse liver development in live mice without surgery, opens up new possibilities for research on Plasmodium liver infections and for validating the effect of drugs and vaccines on the liver stage of Plasmodium. PMID:19924309

Challenges for achieving safe and effective radical cure of Plasmodium vivax: a round table discussion of the APMEN Vivax Working Group.

PubMed

Thriemer, Kamala; Ley, Benedikt; Bobogare, Albino; Dysoley, Lek; Alam, Mohammad Shafiul; Pasaribu, Ayodhia P; Sattabongkot, Jetsumon; Jambert, Elodie; Domingo, Gonzalo J; Commons, Robert; Auburn, Sarah; Marfurt, Jutta; Devine, Angela; Aktaruzzaman, Mohammad M; Sohel, Nayeem; Namgay, Rinzin; Drukpa, Tobgyel; Sharma, Surender Nath; Sarawati, Elvieda; Samad, Iriani; Theodora, Minerva; Nambanya, Simone; Ounekham, Sonesay; Mudin, Rose Nanti Binti; Da Thakur, Garib; Makita, Leo Sora; Deray, Raffy; Lee, Sang-Eun; Boaz, Leonard; Danansuriya, Manjula N; Mudiyanselage, Santha D; Chinanonwait, Nipon; Kitchakarn, Suravadee; Nausien, Johnny; Naket, Esau; Duc, Thang Ngo; Do Manh, Ha; Hong, Young S; Cheng, Qin; Richards, Jack S; Kusriastuti, Rita; Satyagraha, Ari; Noviyanti, Rintis; Ding, Xavier C; Khan, Wasif Ali; Swe Phru, Ching; Guoding, Zhu; Qi, Gao; Kaneko, Akira; Miotto, Olivo; Nguitragool, Wang; Roobsoong, Wanlapa; Battle, Katherine; Howes, Rosalind E; Roca-Feltrer, Arantxa; Duparc, Stephan; Bhowmick, Ipsita Pal; Kenangalem, Enny; Bibit, Jo-Anne; Barry, Alyssa; Sintasath, David; Abeyasinghe, Rabindra; Sibley, Carol H; McCarthy, James; von Seidlein, Lorenz; Baird, J Kevin; Price, Ric N

2017-04-05

The delivery of safe and effective radical cure for Plasmodium vivax is one of the greatest challenges for achieving malaria elimination from the Asia-Pacific by 2030. During the annual meeting of the Asia Pacific Malaria Elimination Network Vivax Working Group in October 2016, a round table discussion was held to discuss the programmatic issues hindering the widespread use of primaquine (PQ) radical cure. Participants included 73 representatives from 16 partner countries and 33 institutional partners and other research institutes. In this meeting report, the key discussion points are presented and grouped into five themes: (i) current barriers for glucose-6-phosphate deficiency (G6PD) testing prior to PQ radical cure, (ii) necessary properties of G6PD tests for wide scale deployment, (iii) the promotion of G6PD testing, (iv) improving adherence to PQ regimens and (v) the challenges for future tafenoquine (TQ) roll out. Robust point of care (PoC) G6PD tests are needed, which are suitable and cost-effective for clinical settings with limited infrastructure. An affordable and competitive test price is needed, accompanied by sustainable funding for the product with appropriate training of healthcare staff, and robust quality control and assurance processes. In the absence of quantitative PoC G6PD tests, G6PD status can be gauged with qualitative diagnostics, however none of the available tests is currently sensitive enough to guide TQ treatment. TQ introduction will require overcoming additional challenges including the management of severely and intermediately G6PD deficient individuals. Robust strategies are needed to ensure that effective treatment practices can be deployed widely, and these should ensure that the caveats are outweighed by  the benefits of radical cure for both the patients and the community. Widespread access to quality controlled G6PD testing will be critical.

Antiplasmodial activities of dyes against Plasmodium falciparum asexual and sexual stages: Contrasted uptakes of triarylmethanes Brilliant green, Green S (E142), and Patent Blue V (E131) by erythrocytes.

PubMed

Leba, Louis-Jérôme; Popovici, Jean; Estevez, Yannick; Pelleau, Stéphane; Legrand, Eric; Musset, Lise; Duplais, Christophe

2017-12-01

The search for safe antimalarial compounds acting against asexual symptom-responsible stages and sexual transmission-responsible forms of Plasmodium species is one of the major challenges in malaria elimination programs. So far, among current drugs approved for human use, only primaquine has transmission-blocking activity. The discovery of small molecules targeting different Plasmodium falciparum life stages remains a priority in antimalarial drug research. In this context, several independent studies have recently reported antiplasmodial and transmission-blocking activities of commonly used stains, dyes and fluorescent probes against P. falciparum including chloroquine-resistant isolates. Herein we have studied the antimalarial activities of dyes with different scaffold and we report that the triarylmethane dye (TRAM) Brilliant green inhibits the growth of asexual stages (IC 50  ≤ 2 μM) and has exflagellation-blocking activity (IC 50  ≤ 800 nM) against P. falciparum reference strains (3D7, 7G8) and chloroquine-resistant clinical isolate (Q206). In a second step we have investigated the antiplasmodial activities of two polysulfonated triarylmethane food dyes. Green S (E142) is weakly active against P. falciparum asexual stage (IC 50 ≃ 17 μM) whereas Patent Blue V (E131) is inactive in both antimalarial assays. By applying liquid chromatography techniques for the culture supernatant analysis after cell washings and lysis, we report the detection of Brilliant green in erythrocytes, the selective uptake of Green S (E142) by infected erythrocytes, whereas Patent Blue V (E131) could not be detected within non-infected and 3D7-infected erythrocytes. Overall, our results suggest that two polysulfonated food dyes might display different affinity with transporters or channels on infected RBC membrane. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Comparison of MDCK-MDR1 and Caco-2 cell based permeability assays for anti-malarial drug screening and drug investigations.

PubMed

Jin, Xiannu; Luong, Thu-Lan; Reese, Necole; Gaona, Heather; Collazo-Velez, Vanessa; Vuong, Chau; Potter, Brittney; Sousa, Jason C; Olmeda, Raul; Li, Qigui; Xie, Lisa; Zhang, Jing; Zhang, Ping; Reichard, Greg; Melendez, Victor; Marcsisin, Sean R; Pybus, Brandon S

2014-01-01

Malaria is a major health concern and affects over 300million people a year. Accordingly, there is an urgent need for new efficacious anti-malarial drugs. A major challenge in developing new anti-malarial drugs is to design active molecules that have preferable drug-like characteristics. These "drug-like" characteristics include physiochemical properties that affect drug absorption, distribution, metabolism, and excretion (ADME). Compounds with poor ADME profiles will likely fail in vivo due to poor pharmacokinetics and/or other drug delivery related issues. There have been numerous assays developed in order to pre-screen compounds that would likely fail in further development due to poor absorption properties including PAMPA, Caco-2, and MDCK permeability assays. The use of cell-based permeability assays such as Caco-2 and MDCK serve as surrogate indicators of drug absorption and transport, with the two approaches often used interchangeably. We sought to evaluate both approaches in support of anti-malarial drug development. Accordingly, a comparison of both assays was conducted utilizing apparent permeability coefficient (Papp) values determined from liquid chromatography/tandem mass spectrometry (LC-MS) analyses. Both Caco-2 and MDCK permeability assays produced similar Papp results for potential anti-malarial compounds with low and medium permeability. Differences were observed for compounds with high permeability and compounds that were P-gp substrates. Additionally, the utility of MDCK-MDR1 permeability measurements was demonstrated in probing the role of P-glycoprotein transport in Primaquine-Chloroquine drug-drug interactions in comparison with in vivo pharmacokinetic changes. This study provides an in-depth comparison of the Caco-2 and MDCK-MDR1 cell based permeability assays and illustrates the utility of cell-based permeability assays in anti-malarial drug screening/development in regard to understanding transporter mediated changes in drug absorption/distribution. Published by Elsevier Inc.

Focused Screening and Treatment (FSAT): A PCR-Based Strategy to Detect Malaria Parasite Carriers and Contain Drug Resistant P. falciparum, Pailin, Cambodia

PubMed Central

Hoyer, Stefan; Nguon, Sokomar; Kim, Saorin; Habib, Najibullah; Khim, Nimol; Sum, Sarorn; Christophel, Eva-Maria; Bjorge, Steven; Thomson, Andrew; Kheng, Sim; Chea, Nguon; Yok, Sovann; Top, Samphornarann; Ros, Seyha; Sophal, Uth; Thompson, Michelle M.; Mellor, Steve; Ariey, Frédéric; Witkowski, Benoit; Yeang, Chhiang; Yeung, Shunmay; Duong, Socheat; Newman, Robert D.; Menard, Didier

2012-01-01

Recent studies have shown that Plasmodium falciparum malaria parasites in Pailin province, along the border between Thailand and Cambodia, have become resistant to artemisinin derivatives. To better define the epidemiology of P. falciparum populations and to assess the risk of the possible spread of these parasites outside Pailin, a new epidemiological tool named “Focused Screening and Treatment” (FSAT), based on active molecular detection of asymptomatic parasite carriers was introduced in 2010. Cross-sectional malariometric surveys using PCR were carried out in 20 out of 109 villages in Pailin province. Individuals detected as P. falciparum carriers were treated with atovaquone-proguanil combination plus a single dose of primaquine if the patient was non-G6PD deficient. Interviews were conducted to elicit history of cross-border travel that might contribute to the spread of artemisinin-resistant parasites. After directly observed treatment, patients were followed up and re-examined on day 7 and day 28. Among 6931 individuals screened, prevalence of P. falciparum carriers was less than 1%, of whom 96% were asymptomatic. Only 1.6% of the individuals had a travel history or plans to go outside Cambodia, with none of those tested being positive for P. falciparum. Retrospective analysis, using 2010 routine surveillance data, showed significant differences in the prevalence of asymptomatic carriers discovered by FSAT between villages classified as “high risk” and “low risk” based on malaria incidence data. All positive individuals treated and followed-up until day 28 were cured. No mutant-type allele related to atovaquone resistance was found. FSAT is a potentially useful tool to detect, treat and track clusters of asymptomatic carriers of P. falciparum along with providing valuable epidemiological information regarding cross-border movements of potential malaria parasite carriers and parasite gene flow. PMID:23049687

Frequency of malaria and glucose-6-phosphate dehydrogenase deficiency in Tajikistan.

PubMed

Rebholz, Cornelia E; Michel, Anette J; Maselli, Daniel A; Saipphudin, Karimov; Wyss, Kaspar

2006-06-16

During the Soviet era, malaria was close to eradication in Tajikistan. Since the early 1990s, the disease has been on the rise and has become endemic in large areas of southern and western Tajikistan. The standard national treatment for Plasmodium vivax is based on primaquine. This entails the risk of severe haemolysis for patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Seasonal and geographical distribution patterns as well as G6PD deficiency frequency were analysed with a view to improve understanding of the current malaria situation in Tajikistan. Spatial and seasonal distribution was analysed, applying a risk model that included key environmental factors such as temperature and the availability of mosquito breeding sites. The frequency of G6PD deficiency was studied at the health service level, including a cross-sectional sample of 382 adult men. Analysis revealed high rates of malaria transmission in most districts of the southern province of Khatlon, as well as in some zones in the northern province of Sughd. Three categories of risk areas were identified: (i) zones at relatively high malaria risk with high current incidence rates, where malaria control and prevention measures should be taken at all stages of the transmission cycle; (ii) zones at relatively high malaria risk with low current incidence rates, where malaria prevention measures are recommended; and (iii) zones at intermediate or low malaria risk with low current incidence rates where no particular measures appear necessary. The average prevalence of G6PD deficiency was 2.1% with apparent differences between ethnic groups and geographical regions. The study clearly indicates that malaria is a serious health issue in specific regions of Tajikistan. Transmission is mainly determined by temperature. Consequently, locations at lower altitude are more malaria-prone. G6PD deficiency frequency is too moderate to require fundamental changes in standard national treatment of cases of P. vivax.

Genotypic and phenotypic characterization of G6PD deficiency in Bengali adults with severe and uncomplicated malaria.

PubMed

Plewes, Katherine; Soontarawirat, Ingfar; Ghose, Aniruddha; Bancone, Germana; Kingston, Hugh W F; Herdman, M Trent; Leopold, Stije J; Ishioka, Haruhiko; Faiz, Md Abul; Anstey, Nicholas M; Day, Nicholas P J; Hossain, Md Amir; Imwong, Mallika; Dondorp, Arjen M; Woodrow, Charles J

2017-03-29

Control of malaria increasingly involves administration of 8-aminoquinolines, with accompanying risk of haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Few data on the prevalence and genotypic basis of G6PD deficiency are available from Bangladesh, where malaria remains a major problem in the South (Chittagong Division). The aim of this study was to determine the prevalence of G6PD deficiency, and associated G6PD genotypes, in adults with falciparum malaria in southern Bangladesh. G6PD status was assessed via a combination of fluorescent spot testing (FST) and genotyping in 141 Bengali patients admitted with falciparum malaria to two centres in Chittagong Division from 2012 to 2014. In addition, an analysis of genomic data from 1000 Genomes Project was carried out among five healthy Indian subcontinent populations. One male patient with uncomplicated malaria was found to have G6PD deficiency on FST and a genotype associated with deficiency (hemizygous Orissa variant). In addition, there were two female patients heterozygous for deficiency variants (Orissa and Kerala-Kalyan). These three patients had a relatively long duration of symptoms prior to admission compared to G6PD normal cases, possibly suggesting an interaction with parasite multiplication rate. In addition, one of 27 healthy local controls was deficient on FST and hemizygous for the Mahidol variant of G6PD deficiency. Examination of 1000 Genomes Project sequencing data across the Indian subcontinent showed that 19/723 chromosomes (2.63%) carried a variant associated with deficiency. In the Bengali from Bangladesh 1000 Genomes population, three of 130 chromosomes (2.31%) carried deficient alleles; this included single chromosomes carrying the Kerala-Kalyan and Orissa variants. In line with other recent work, G6PD deficiency is uncommon in Bengalis in Bangladesh. Further studies of particular ethnic groups are needed to evaluate the potential risk of wide deployment of primaquine in malaria control efforts in Bangladesh.

The prevalence of glucose-6-phosphate dehydrogenase deficiency in Gambian school children.

PubMed

Okebe, Joseph; Amambua-Ngwa, Alfred; Parr, Jason; Nishimura, Sei; Daswani, Melissa; Takem, Ebako N; Affara, Muna; Ceesay, Serign J; Nwakanma, Davis; D'Alessandro, Umberto

2014-04-17

Primaquine, the only available drug effective against Plasmodium falciparum sexual stages, induces also a dose-dependent haemolysis, especially in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals. Therefore, it is important to determine the prevalence of this deficiency in areas that would potentially benefit from its use. The prevalence of G6PD deficiency by genotype and enzyme activity was determined in healthy school children in The Gambia. Blood samples from primary school children collected during a dry season malaria survey were screened for G6PDd and malaria infection. Genotypes for allele mutations reported in the country; 376, 202A-, 968A- and 542 were analysed while enzyme activity (phenotype) was assayed using a semi-quantitative commercial test kit. Enzyme activity values were fitted in a finite mixture model to determine the distribution and calculate a cut-off for deficiency. The association between genotype and phenotype for boys and girls as well as the association between mutant genotype and deficient phenotype was analysed. Samples from 1,437 children; 51% boys were analysed. The prevalence of P. falciparum malaria infection was 14%. The prevalence of the 202A-, 968 and 542 mutations was 1.8%, 2.1% and 1.0%, respectively, and higher in boys than in girls. The prevalence of G6PDd phenotype was 6.4% (92/1,437), 7.8% (57/728) in boys and 4.9% (35/709) in girls with significantly higher odds in the former (OR 1.64, 95% CI 1.05, 2.53, p = 0.026). The deficient phenotype was associated with reduced odds of malaria infection (OR 0.77, 95% CI 0.36, 1.62, p = 0.49). There is a weak association between genotype and phenotype estimates of G6PDd prevalence. The phenotype expression of deficiency represents combinations of mutant alleles rather than specific mutations. Genotype studies in individuals with a deficient phenotype would help identify alleles responsible for haemolysis.

[Malaria situation and evaluation on the control effect in Henan Province during 1990-2005].

PubMed

Liu, Xue-zhou; Xu, Bian-li

2006-06-01

To analyze malaria situation and evaluate the effect of control program in Henan Province during 1990-2005. Data were collected and analyzed on the measures and effects of malaria control, vector surveillance, blood examination for cases with fever and serological surveillance in the province during 1990-2005. In the 16 years, a total of 802,700 people were given pre-transmission season treatment with chloroquine and primaquine for a radical cure of vivax malaria, chemoprophylaxis was given to 764,300 people at high risk during the transmission season, treatment or presumptive treatment was given to 43,891 cases. 11,216,100 cases with fever were tested and 11,213 (0.10%) were found positive accounting for 29.01% (11 213/338 654) of all malaria cases. A total of 1 332 800 bed nets were treated with insecticide and 1,999 300 people were protected in 1990-1992 and 1996-1999. 34,846 residents including pupils were tested with IFAT in 1990-2000 and 1149 (3.30%) were positive. The parasite rate amongst 71,234 local residents including pupils was 0.40% (286/71,234). The principal transmitting vectors were Anopheles sinensis and An. anthropophagus. The man-biting habit for An. sinensis and An. anthropophagus was 0.0608 and 0.3143 respectively, and the vectorial capacity of An. anthropophagus was 22.4 times higher than that of An. sinensis. In this period, 38,654 malaria cases were reported in the province and the annual malaria incidence was 2.62 per hundred thousand, the lowest annual incidence was in 1992 (0.37 per hundred thousand). 70.05% (27,076/38,654) of these malaria cases were from areas where An. anthropophagus was present. In general, the malaria control activities have been effective and the epidemiological situation kept stable in Henan Province, although in some areas the situation is unstable and outbreak spots or focal epidemics occur.

Malaria elimination in Haiti by the year 2020: an achievable goal?

PubMed

Boncy, Paul Jacques; Adrien, Paul; Lemoine, Jean Frantz; Existe, Alexandre; Henry, Patricia Jean; Raccurt, Christian; Brasseur, Philippe; Fenelon, Natael; Dame, John B; Okech, Bernard A; Kaljee, Linda; Baxa, Dwayne; Prieur, Eric; El Badry, Maha A; Tagliamonte, Massimiliano S; Mulligan, Connie J; Carter, Tamar E; Beau de Rochars, V Madsen; Lutz, Chelsea; Parke, Dana M; Zervos, Marcus J

2015-06-05

Haiti and the Dominican Republic, which share the island of Hispaniola, are the last locations in the Caribbean where malaria still persists. Malaria is an important public health concern in Haiti with 17,094 reported cases in 2014. Further, on January 12, 2010, a record earthquake devastated densely populated areas in Haiti including many healthcare and laboratory facilities. Weakened infrastructure provided fertile reservoirs for uncontrolled transmission of infectious pathogens. This situation results in unique challenges for malaria epidemiology and elimination efforts. To help Haiti achieve its malaria elimination goals by year 2020, the Laboratoire National de Santé Publique and Henry Ford Health System, in close collaboration with the Direction d'Épidémiologie, de Laboratoire et de Recherches and the Programme National de Contrôle de la Malaria, hosted a scientific meeting on "Elimination Strategies for Malaria in Haiti" on January 29-30, 2015 at the National Laboratory in Port-au-Prince, Haiti. The meeting brought together laboratory personnel, researchers, clinicians, academics, public health professionals, and other stakeholders to discuss main stakes and perspectives on malaria elimination. Several themes and recommendations emerged during discussions at this meeting. First, more information and research on malaria transmission in Haiti are needed including information from active surveillance of cases and vectors. Second, many healthcare personnel need additional training and critical resources on how to properly identify malaria cases so as to improve accurate and timely case reporting. Third, it is necessary to continue studies genotyping strains of Plasmodium falciparum in different sites with active transmission to evaluate for drug resistance and impacts on health. Fourth, elimination strategies outlined in this report will continue to incorporate use of primaquine in addition to chloroquine and active surveillance of cases. Elimination of malaria in Haiti will require collaborative multidisciplinary approaches, sound strategic planning, and strong ownership of strategies by the Haiti Ministère de la Santé Publique et de la Population.

High risk of Plasmodium vivax malaria following splenectomy in Papua, Indonesia.

PubMed

Kho, Steven; Andries, Benediktus; Poespoprodjo, Jeanne R; Commons, Robert J; Shanti, Putu A I; Kenangalem, Enny; Douglas, Nicholas M; Simpson, Julie A; Sugiarto, Paulus; Anstey, Nicholas M; Price, Ric N

2018-05-16

Splenectomy increase the risk of severe and fatal infections, however the risk of Plasmodium vivax malaria is unknown. We quantified the Plasmodium species-specific risks of malaria and other outcomes following splenectomy in patients attending a hospital in Papua, Indonesia. Records of all patients attending Mitra-Masyarakat Hospital 2004-2013 were reviewed, identifying those who underwent splenectomy. Subsequent risks of specific clinical outcomes within 12 months for splenectomized patients were compared to non-splenectomized patients from their first recorded hospital admission. In addition, patients splenectomized for trauma between 2015-2016 were followed prospectively for 14 months. Of the 10,774 non-pregnant patients aged 12-60 years hospitalized during 2004-2013, 67 underwent splenectomy. Compared to non-splenectomized inpatients, patients undergoing splenectomy had a 5-fold higher rate of malaria presentation within 12 months (Adjusted Hazard Ratio (AHR)=5.0 [95%CI:3.4-7.3], p<0.001). The rate was greater for P. vivax (AHR=7.8 [95%CI:5.0-12.3], p<0.001) compared to P. falciparum (AHR=3.0 [95%CI:1.7-5.4], p<0.001). Splenectomized patients had greater risk of being hospitalized for any cause (AHR=1.8 [95%CI:1.0-3.0], p=0.037) and, diarrheal illness (AHR=3.5 [95%CI:1.3-9.6], p=0.016). In the prospective cohort, 8 of 11 splenectomized patients had 18 episodes of malaria over 14 months, 12 episodes of P. vivax in 8 patients and 6 episodes of P. falciparum in 6 patients. Splenectomy is associated with a high risk of malaria, greater for P. vivax than P. falciparum. Eradication of P. vivax hypnozoites using primaquine (radical cure) and subsequent malaria prophylaxis is warranted in patients following splenectomy in malaria-endemic areas, particularly in the early post-operative period.

Primaquine or other 8-aminoquinolines for reducing Plasmodium falciparum transmission

PubMed Central

Graves, Patricia M; Choi, Leslie; Gelband, Hellen; Garner, Paul

2018-01-01

Background The 8-aminoquinoline (8AQ) drugs act on Plasmodium falciparum gametocytes, which transmit malaria from infected people to mosquitoes. In 2012, the World Health Organization (WHO) recommended a single dose of 0.25 mg/kg primaquine (PQ) be added to malaria treatment schedules in low-transmission areas or those with artemisinin resistance. This replaced the previous recommendation of 0.75 mg/kg, aiming to reduce haemolysis risk in people with glucose-6-phosphate dehydrogenase deficiency, common in people living in malarious areas. Whether this approach, and at this dose, is effective in reducing transmission is not clear. Objectives To assess the effects of single dose or short-course PQ (or an alternative 8AQ) alongside treatment for people with P. falciparum malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; and the WHO International Clinical Trials Registry Platform (ICRTP) portal using ‘malaria*', ‘falciparum', ‘primaquine', ‘8-aminoquinoline', and eight 8AQ drug names as search terms. We checked reference lists of included trials, and contacted researchers and organizations. Date of last search: 21 July 2017. Selection criteria Randomized controlled trials (RCTs) or quasi-RCTs in children or adults, adding PQ (or alternative 8AQ) as a single dose or short course alongside treatment for P. falciparum malaria. Data collection and analysis Two authors screened abstracts, applied inclusion criteria, and extracted data. We sought evidence on transmission (community incidence), infectiousness (people infectious and mosquitoes infected), and potential infectiousness (gametocyte measures assessed by microscopy or polymerase chain reaction [PCR]). We grouped trials into artemisinin and non-artemisinin treatments, and stratified by PQ dose (low, 0.2 to 0.25 mg/kg; moderate, 0.4 to 0.5 mg/kg; high, 0.75 mg/kg). We used GRADE, and absolute effects of infectiousness using trial control groups. Main results We included 24 RCTs and one quasi-RCT, comprising 43 arms. Fourteen trials evaluated artemisinin treatments (23 arms), nine trials evaluated non-artemisinin treatments (13 arms), and two trials included both artemisinin and non-artemisinin arms (three and two arms, respectively). Two trial arms used bulaquine. Seven PQ arms used low dose (six with artemisinin), 11 arms used moderate dose (seven with artemisinin), and the remaining arms used high dose. Fifteen trials tested for G6PD status: 11 excluded participants with G6PD deficiency, one included only those with G6PD deficiency, and three included all, irrespective of status. The remaining 10 trials either did not test or did not report on testing. No cluster trials evaluating community effects on malaria transmission met the inclusion criteria. With artemisinin treatment Low dose PQ Infectiousness (participants infectious to mosquitoes) was reduced (day 3 or 4: RR 0.12, 95% CI 0.02 to 0.88, 3 trials, 105 participants; day 8: RR 0.34, 95% CI 0.07 to 1.58, 4 trials, 243 participants; low certainty evidence). This translates to a reduction in percentage of people infectious on day 3 or 4 from 14% to 2%, and, for day 8, from 4% to 1%; the waning infectiousness in the control group by day 8 making the absolute effect smaller by day 8. For gametocytes detected by PCR, there was little or no effect of PQ at day 3 or 4 (RR 1.02, 95% CI 0.87 to 1.21; 3 trials, 414 participants; moderate certainty evidence); with reduction at day 8 (RR 0.52, 95% CI 0.41 to 0.65; 4 trials, 532 participants; high certainty evidence). Severe haemolysis was infrequent, with or without PQ, in these groups with few G6PD-deficient individuals (RR 0.98, 95% CI 0.69 to 1.39; 4 trials, 752 participants, moderate certainty evidence). Moderate dose PQ Infectiousness was reduced (day 3 or 4: RR 0.13, 95% CI 0.02 to 0.94; 3 trials, 109 participants; day 8 RR 0.33, 95% CI 0.07 to 1.57; 4 trials, 246 participants; low certainty evidence). Illustrative risk estimates for moderate dose were the same as low dose. The pattern and level of certainty of evidence with gametocytes detected by PCR was the same as low dose, and severe haemolysis was infrequent in both groups. High dose PQ Infectiousness was reduced (day 4: RR 0.2, 95% CI 0.02 to 1.68, 1 trial, 101 participants; day 8: RR 0.18, 95% CI 0.02 to 1.41, 2 trials, 181 participants, low certainty evidence). The effects on gametocyte prevalence showed a similar pattern to moderate and low dose PQ. Trials did not systematically report evidence of haemolysis. With non-artemisinin treatment Trials with non-artemisinin treatment have been conducted only for moderate and high dose PQ. With high dose, infectiousness appeared markedly reduced on day 5 (RR 0.09, 95% CI 0.01 to 0.62; 30 participants, very low certainty evidence), with similar reductions at day 8. For both moderate dose (two trials with 221 people) and high dose (two trials with 30 people), reduction in gametocytes (detected by microscopy) showed similar patterns as for artemisinin treatments, with little or no effect at day 4 or 5, and larger effects by day 8. No trials with non-artemisinin partner drugs systematically sought evidence of severe haemolysis. Two trials comparing bulaquine with PQ suggest bulaquine may have larger effects on gametocytes by microscopy on day 8 (RR 0.41, 95% CI 0.26 to 0.66; 2 trials, 112 participants). Authors' conclusions A single low dose of PQ (0.25 mg/kg) added to artemisinin-based combination therapy for malaria reduces infectiousness of people to mosquitoes at day 3-4 and day 8, and appears as effective as higher doses. The absolute effect is greater at day 3 or 4, and smaller at day 8, in part because of the lower infectiousness in the control group. There was no evidence of increased haemolysis at 0.25 mg/kg, but few G6PD-deficient individuals were included in the trials. The effect on infectiousness precedes the effect of PQ on gametocyte prevalence. We do not know whether single dose PQ could reduce malaria transmission at community level. What is the aim of this review? To assess the effects of adding a single dose of primaquine (PQ) to treatment for falciparum malaria to reduce disease transmission. This Cochrane Review update includes 25 controlled trials. The date of latest search was 21 July 2017. Key messages A single low dose of PQ, at 0.25 mg/kg, which the World Health Organization (WHO) recommends adding to artemisinin-based combination therapy for malaria, reduces infectiousness (transmission from people to mosquitoes). In the trials, the percentage of people who infected mosquitoes three to four days after treatment was reduced from 14% to 2%, with a smaller effect at day 8, from 4% to 1%, with no evidence of harm. What was studied in the review PQ kills gametocytes (malaria transmission stages) of the falciparum malaria parasite. Gametocytes infect mosquitoes during a bite, thus perpetuating transmission. There is concern that PQ may cause red blood cells to burst (haemolysis) in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency, a genetically-determined condition common in many malaria-endemic settings, which can lead to anaemia. Recognizing concerns about the risk of haemolysis, the WHO reduced the recommended PQ dose from 0.75 mg/kg to 0.25 mg/kg in 2012. Ideally, this approach would be tested by randomly assigning villages to standard malaria treatment, or standard treatment plus a low dose of PQ, then measuring the effect on malaria over time but this would be difficult and expensive. So, indirect indicators are used to shed light on effectiveness, including feeding studies, in which mosquitoes are allowed to feed on people (or their blood), comparing those who were assigned PQ with those who were not. Alternatively, researchers may simply monitor the presence (prevalence), number (density), and duration (time of persistence) of gametocytes in the blood of people after different treatments, assuming that gametocytes are viable irrespective of exposure to PQ. What the research says The 25 included trials span several decades and include a variety of treatments and PQ doses. Related to safety assessment, some trials tested participants for G6PD activity. Other trials reported results based on their G6PD status, others did not test (or did not say whether they did), and others tested and excluded people with G6PD deficiency. There were no ideal community-level studies that would answer the question directly. Five feeding trials with multiple arms included three low-dose, three medium-dose, and two high-dose comparisons, showing a markedly reduced proportion of people infectious who received PQ in trials with any events. Two trials using older malaria treatments and high dose PQ had similar results. The other trials focused on indirect measures of potential infectiousness of humans to mosquitoes. In these trials, PQ shortened the period of potential infectiousness, with a lower prevalence and density of gametocytes up to day 8 after treatment. The effect was similar at all PQ dose levels. Few serious haemolytic events occurred in these trials, but PQ did affect non-serious haemoglobin measures, even at low doses. What are the main results of the review? A single low dose of PQ added to an artemisinin regimen for malaria reduces infectiousness to mosquitoes and is relatively safe for most people. PQ at WHO-recommended dose reduces infectiousness to mosquitoes on day 3-4 and day 8 with no evidence of harm. It is unclear whether this reduction would materially reduce malaria transmission in communities. PMID:29393511

Evaluation of the Diagnostic Accuracy of CareStart G6PD Deficiency Rapid Diagnostic Test (RDT) in a Malaria Endemic Area in Ghana, Africa

PubMed Central

Adu-Gyasi, Dennis; Asante, Kwaku Poku; Newton, Sam; Dosoo, David; Amoako, Sabastina; Adjei, George; Amoako, Nicholas; Ankrah, Love; Tchum, Samuel Kofi; Mahama, Emmanuel; Agyemang, Veronica; Kayan, Kingsley; Owusu-Agyei, Seth

2015-01-01

Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most widespread enzyme defect that can result in red cell breakdown under oxidative stress when exposed to certain medicines including antimalarials. We evaluated the diagnostic accuracy of CareStart G6PD deficiency Rapid Diagnostic Test (RDT) as a point-of-care tool for screening G6PD deficiency. Methods A cross-sectional study was conducted among 206 randomly selected and consented participants from a group with known G6PD deficiency status between February 2013 and June 2013. A maximum of 1.6ml of capillary blood samples were used for G6PD deficiency screening using CareStart G6PD RDT and Trinity qualitative with Trinity quantitative methods as the “gold standard”. Samples were also screened for the presence of malaria parasites. Data entry and analysis were done using Microsoft Access 2010 and Stata Software version 12. Kintampo Health Research Centre Institutional Ethics Committee granted ethical approval. Results The sensitivity (SE) and specificity (SP) of CareStart G6PD deficiency RDT was 100% and 72.1% compared to Trinity quantitative method respectively and was 98.9% and 96.2% compared to Trinity qualitative method. Malaria infection status had no significant (P=0.199) change on the performance of the G6PD RDT test kit compared to the “gold standard”. Conclusions The outcome of this study suggests that the diagnostic performance of the CareStart G6PD deficiency RDT kit was high and it is acceptable at determining the G6PD deficiency status in a high malaria endemic area in Ghana. The RDT kit presents as an attractive tool for point-of-care G6PD deficiency for rapid testing in areas with high temperatures and less expertise. The CareStart G6PD deficiency RDT kit could be used to screen malaria patients before administration of the fixed dose primaquine with artemisinin-based combination therapy. PMID:25885097

Donor support for quality assurance and pharmacovigilance of anti-malarials in malaria-endemic countries.

PubMed

Kovacs, Stephanie D; Mills, Brianna M; Stergachis, Andy

2017-07-11

Malaria control efforts have been strengthened by funding from donor groups and government agencies. The Global Fund to Fight AIDS, Tuberculosis and the Malaria (Global Fund), the US President's Malaria Initiative (PMI) account for the majority of donor support for malaria control and prevention efforts. Pharmacovigilance (PV), which encompasses all activities relating to the detection, assessment, understanding, and prevention of adverse effects or any other drug-related problem, is a necessary part of efforts to reduce drug resistance and improve treatment outcomes. This paper reports on an analysis of PV plans in the Global Fund and PMI and World Bank's grants for malaria prevention and control. All active malaria grants as of September 2015 funded by the Global Fund and World Bank, and fiscal year 2015 and 2016 PMI Malaria Operational Plans (MOP) were identified. The total amount awarded for PV-related activities and drug quality assurance was abstracted. A Key-Word-in-Context (KWIC) analysis was conducted for the content of each grant. Specific search terms consisted of pharmacovigilance, pregn*, registry, safety, adverse drug, mass drug administration, primaquine, counterfeit, sub-standard, and falsified. Grants that mentioned PV activities identified in the KWIC search, listed PV in their budgets, or included the keywords: counterfeit, sub-standard, falsified, mass drug administration, or adverse event were thematically coded using Dedoose software version 7.0. The search identified 159 active malaria grants including 107 Global Fund grants, 39 fiscal year 2015 and 2016 PMI grants and 13 World Bank grants. These grants were primarily awarded to low-income countries (57.2%) and in sub-Saharan Africa (SSA) (70.4%). Thirty-seven (23.3%) grants included a budget line for PV- or drug quality assurance-related activities, including 21 PMI grants and 16 Global Fund grants. Only 23 (14.5%) grants directly mentioned PV. The primary focus area was improving drug quality monitoring, especially among the PMI grants. The results of the analysis demonstrate that funding for PV has not been sufficiently prioritized by either the key malaria donor organizations or by the recipient countries, as reflected in their grant proposal submissions and MOPs.

Molecular evaluation of pvdhfr and pvmdr-1 mutants in Plasmodium vivax isolates after treatment with sulfadoxine/pyrimethamine and chloroquine in Iran during 2001-2016.

PubMed

Parsaei, Mahdi; Raeisi, Ahmad; Spotin, Adel; Shahbazi, Abbas; Mahami-Oskouei, Mahmoud; Hazratian, Teimour; Khorashad, Alireza Salimi; Zaman, Jalal; Bazmani, Ahad; Sarafraz, Sedighe

2018-06-19

The rising use of sulfadoxine/pyrimethamine (SP) in the treatment of chloroquine (CQ)-resistant Plasmodium falciparum has resulted in increased exposure to P. vivax isolates in Iran, where both species are being circulated. In this investigation, the frequency of pvdhfr and pvmdr-1 mutants was assessed in P. vivax strains during 2001-2016 after the introduction of SP/CQ in malarious areas of Iran. The P. vivax isolates (n, 52) were obtained from autochthonous samples in Southeast Iran during 2015-2016. The genomic DNA was extracted and examined using nested polymerase chain reaction-(PCR) and sequencing. Mutations were detected in pvdhfr codons P33L (21.2%), T61 M (25%), S93H (3.9%), and S117 T (1.9%) and 5 isolates showed double mutations (33 L/61 M, 7.7%; 33 L/117 T, 1.9%). No mutation was identified in pvdhfr codons F57 and S58. The pvmdr-1 1076 L mutation was detected in 93.3% of P. vivax isolates. The findings indicated that the frequency of three codons of pvdhfr F57/S58/S117 has decreased from 2001 (1.05%/7.0%/16.9%) to 2016 (0%/0%/1.9%). Genomic analysis of pvmdr-1 showed that the frequency of 1076 L has gradually increased from 2013 (93%) to 2016 (93.3%) (P > .05). The results demonstrated that P. vivax isolates are probably being exited under SP pressure, which reflects the appropriate level of training for field microscopists, as established by Iranian policymakers. Emergent pvdhfr codons 33L, 61M, and 93H should be noticed in plausible drug tolerance and treatment plans. The high prevalence of pvmdr-1 1076L mutation shows that efficacy of CQ combination with primaquine may be in danger of being compromised, however further investigations are needed to evaluate the clinical importance of CQ-resistant P. vivax isolates. Copyright © 2018 Elsevier B.V. All rights reserved.

Treatment-seeking behaviour and associated costs for malaria in Papua, Indonesia.

PubMed

Karyana, Muhammad; Devine, Angela; Kenangalem, Enny; Burdarm, Lenny; Poespoprodjo, Jeanne Rini; Vemuri, Ram; Anstey, Nicholas M; Tjitra, Emiliana; Price, Ric N; Yeung, Shunmay

2016-11-08

Malaria remains a significant public health issue in Eastern Indonesia, where multidrug resistant Plasmodium falciparum and Plasmodium vivax are highly prevalent. The objective of this study was to describe treatment-seeking behaviour and household costs prior to a change to a unified treatment policy of dihydroartemisinin-piperaquine in Mimika district, Papua province in 2006. In 2005 a randomized cross-sectional household survey was conducted to collect data on demographics, socio-economic status (SES), treatment-seeking, case management, and household costs. Information on the cost of illness was also collected from patients exiting health facilities, in order to compare the cost of episodes diagnosed as P. vivax compared with those diagnosed as P. falciparum. 825 households were included in the survey. Of the 764 individuals who sought treatment for fever outside the home in the last month, 46% (349/764) went to a public health facility. Of the 894 reported visits to healthcare providers, 48% (433) resulted in a blood test, of which 78% (337) were reportedly positive. Only 10% (17/177) of individuals who reported testing positive for P. falciparum or mixed infection received the first-line treatment of chloroquine with SP, and 38% (61/159) of those with a diagnosis of P. vivax reportedly received the first-line treatment of chloroquine and primaquine. Overall, public facilities were more likely to prescribe the correct prevailing first-line drug combinations than private providers (OR = 3.77 [95% CI 2.31-6.14], p < 0.001). The mean cost to the household of an episode of P. vivax was similar to the cost of P. falciparum [US$44.50 (SD: 46.23) vs US$48.58 (SD: 64.65)]. Private providers were a popular source of treatment for malaria, but adherence to the national guidelines was low and the economic burden of malaria for both P. falciparum and P. vivax infections was substantial. Engagement with the private sector is needed to ensure that patients have access to affordable good quality, effective diagnostics and anti-malarials for both P. falciparum and P. vivax.

The impact of phenotypic and genotypic G6PD deficiency on risk of plasmodium vivax infection: a case-control study amongst Afghan refugees in Pakistan.

PubMed

Leslie, Toby; Briceño, Marnie; Mayan, Ismail; Mohammed, Nasir; Klinkenberg, Eveline; Sibley, Carol Hopkins; Whitty, Christopher J M; Rowland, Mark

2010-05-25

The most common form of malaria outside Africa, Plasmodium vivax, is more difficult to control than P. falciparum because of the latent liver hypnozoite stage, which causes multiple relapses and provides an infectious reservoir. The African (A-) G6PD (glucose-6-phosphate dehydrogenase) deficiency confers partial protection against severe P. falciparum. Recent evidence suggests that the deficiency also confers protection against P. vivax, which could explain its wide geographical distribution in human populations. The deficiency has a potentially serious interaction with antirelapse therapies (8-aminoquinolines such as primaquine). If the level of protection was sufficient, antirelapse therapy could become more widely available. We therefore tested the hypothesis that G6PD deficiency is protective against vivax malaria infection. A case-control study design was used amongst Afghan refugees in Pakistan. The frequency of phenotypic and genotypic G6PD deficiency in individuals with vivax malaria was compared against controls who had not had malaria in the previous two years. Phenotypic G6PD deficiency was less common amongst cases than controls (cases: 4/372 [1.1%] versus controls 42/743 [5.7%]; adjusted odds ratio [AOR] 0.18 [95% confidence interval (CI) 0.06-0.52], p = 0.001). Genetic analysis demonstrated that the G6PD deficiency allele identified (Mediterranean type) was associated with protection in hemizygous deficient males (AOR = 0.12 [95% CI 0.02-0.92], p = 0.041). The deficiency was also protective in females carrying the deficiency gene as heterozygotes or homozygotes (pooled AOR = 0.37 [95% CI 0.15-0.94], p = 0.037). G6PD deficiency (Mediterranean type) conferred significant protection against vivax malaria infection in this population whether measured by phenotype or genotype, indicating a possible evolutionary role for vivax malaria in the selective retention of the G6PD deficiency trait in human populations. Further work is required on the genotypic protection associated with other types of G6PD deficiency and on developing simple point-of-care technologies to detect it before administering antirelapse therapy.

Molecular Analysis of Glucose-6-Phosphate Dehydrogenase Gene Mutations in Bangladeshi Individuals.

PubMed

Sarker, Suprovath Kumar; Islam, Md Tarikul; Eckhoff, Grace; Hossain, Mohammad Amir; Qadri, Syeda Kashfi; Muraduzzaman, A K M; Bhuyan, Golam Sarower; Shahidullah, Mohammod; Mannan, Mohammad Abdul; Tahura, Sarabon; Hussain, Manzoor; Akhter, Shahida; Nahar, Nazmun; Shirin, Tahmina; Qadri, Firdausi; Mannoor, Kaiissar

2016-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked human enzyme defect of red blood cells (RBCs). Individuals with this gene defect appear normal until exposed to oxidative stress which induces hemolysis. Consumption of certain foods such as fava beans, legumes; infection with bacteria or virus; and use of certain drugs such as primaquine, sulfa drugs etc. may result in lysis of RBCs in G6PD deficient individuals. The genetic defect that causes G6PD deficiency has been identified mostly as single base missense mutations. One hundred and sixty G6PD gene mutations, which lead to amino acid substitutions, have been described worldwide. The purpose of this study was to detect G6PD gene mutations in hospital-based settings in the local population of Dhaka city, Bangladesh. Qualitative fluorescent spot test and quantitative enzyme activity measurement using RANDOX G6PDH kit were performed for analysis of blood specimens and detection of G6PD-deficient participants. For G6PD-deficient samples, PCR was done with six sets of primers specific for G6PD gene. Automated Sanger sequencing of the PCR products was performed to identify the mutations in the gene. Based on fluorescence spot test and quantitative enzyme assay followed by G6PD gene sequencing, 12 specimens (11 males and one female) among 121 clinically suspected patient-specimens were found to be deficient, suggesting a frequency of 9.9% G6PD deficiency. Sequencing of the G6PD-deficient samples revealed c.C131G substitution (exon-3: Ala44Gly) in six samples, c.G487A substitution (exon-6:Gly163Ser) in five samples and c.G949A substitution (exon-9: Glu317Lys) of coding sequence in one sample. These mutations either affect NADP binding or disrupt protein structure. From the study it appears that Ala44Gly and Gly163Ser are the most common G6PD mutations in Dhaka, Bangladesh. This is the first study of G6PD mutations in Bangladesh.

Molecular Analysis of Glucose-6-Phosphate Dehydrogenase Gene Mutations in Bangladeshi Individuals

PubMed Central

Sarker, Suprovath Kumar; Hossain, Mohammad Amir; Qadri, Syeda Kashfi; Muraduzzaman, A. K. M.; Bhuyan, Golam Sarower; Shahidullah, Mohammod; Mannan, Mohammad Abdul; Tahura, Sarabon; Hussain, Manzoor; Akhter, Shahida; Nahar, Nazmun; Shirin, Tahmina; Qadri, Firdausi; Mannoor, Kaiissar

2016-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked human enzyme defect of red blood cells (RBCs). Individuals with this gene defect appear normal until exposed to oxidative stress which induces hemolysis. Consumption of certain foods such as fava beans, legumes; infection with bacteria or virus; and use of certain drugs such as primaquine, sulfa drugs etc. may result in lysis of RBCs in G6PD deficient individuals. The genetic defect that causes G6PD deficiency has been identified mostly as single base missense mutations. One hundred and sixty G6PD gene mutations, which lead to amino acid substitutions, have been described worldwide. The purpose of this study was to detect G6PD gene mutations in hospital-based settings in the local population of Dhaka city, Bangladesh. Qualitative fluorescent spot test and quantitative enzyme activity measurement using RANDOX G6PDH kit were performed for analysis of blood specimens and detection of G6PD-deficient participants. For G6PD-deficient samples, PCR was done with six sets of primers specific for G6PD gene. Automated Sanger sequencing of the PCR products was performed to identify the mutations in the gene. Based on fluorescence spot test and quantitative enzyme assay followed by G6PD gene sequencing, 12 specimens (11 males and one female) among 121 clinically suspected patient-specimens were found to be deficient, suggesting a frequency of 9.9% G6PD deficiency. Sequencing of the G6PD-deficient samples revealed c.C131G substitution (exon-3: Ala44Gly) in six samples, c.G487A substitution (exon-6:Gly163Ser) in five samples and c.G949A substitution (exon-9: Glu317Lys) of coding sequence in one sample. These mutations either affect NADP binding or disrupt protein structure. From the study it appears that Ala44Gly and Gly163Ser are the most common G6PD mutations in Dhaka, Bangladesh. This is the first study of G6PD mutations in Bangladesh. PMID:27880809

The Importance of Blood Is Infinite: Conceptions of Blood as Life Force, Rumours and Fear of Trial Participation in a Fulani Village in Rural Gambia

PubMed Central

O’Neill, Sarah; Dierickx, Susan; Okebe, Joseph; Dabira, Edgard; Gryseels, Charlotte; d’Alessandro, Umberto; Peeters Grietens, Koen

2016-01-01

Background Clinical trials require high levels of participation and low drop-out rates to be successful. However, collecting blood samples from individuals recruited into clinical trials can be challenging when there is reticence about blood-taking. In addition to concerns regarding the feasibility of medical research, fears of ‘blood-stealing’ and ‘blood-selling’ have ethical implications related to cultural sensitivity and informed consent. This study explores anxieties around blood-taking during a malaria treatment trial in the Gambia. Methods This case study is based on ethnographic research in one theoretically selected village due to the high reticence to screening for the clinical trial ‘Primaquine's gametocytocidal efficacy in malaria asymptomatic carriers treated with dihydroartemisinin-piperaquine’ carried out in the Gambia between 2013 and 2014. Data collection tools included in-depth interviews, participant observation, informal conversations and group discussions. Results In total only 176 of 411 habitants (42%) in the village accepted having a bloodspot taken to screen for malaria. Although trial recruitment was initially high in the village, some families refused screening when rumours started spreading that the trial team was taking too much blood. Concerns about ‘loss of blood’ were equated to loss of strength and lack of good food to replenish bodily forces. Families in the study village were concerned about the weakness of their body while they had to harvest their crops at the time of recruitment for the trial. Conclusion A common recommendation to prevent and avoid rumours against public health interventions and trials is the provision of full and consistent information during the consent procedure, which is assumed to lead to more accurate knowledge of the purpose of the intervention and increased trial participation. However, even when information provision is continuous, the emergence of rumours can be related to times of uncertainty and perceptions of vulnerability, which are often a reflection of structural inequalities and diverging value orientations between communities and public health institutions. PMID:27525652

Plasmodium falciparum Calcium-Dependent Protein Kinase 2 Is Critical for Male Gametocyte Exflagellation but Not Essential for Asexual Proliferation.

PubMed

Bansal, Abhisheka; Molina-Cruz, Alvaro; Brzostowski, Joseph; Mu, Jianbing; Miller, Louis H

2017-10-17

Drug development efforts have focused mostly on the asexual blood stages of the malaria parasite Plasmodium falciparum Except for primaquine, which has its own limitations, there are no available drugs that target the transmission of the parasite to mosquitoes. Therefore, there is a need to validate new parasite proteins that can be targeted for blocking transmission. P. falciparum calcium-dependent protein kinases ( Pf CDPKs) play critical roles at various stages of the parasite life cycle and, importantly, are absent in the human host. These features mark them as attractive drug targets. In this study, using CRISPR/Cas9 we successfully knocked out Pf CDPK2 from blood-stage parasites, which was previously thought to be an indispensable protein. The growth rate of the Pf CDPK2 knockout (KO) parasites was similar to that of wild-type parasites, confirming that Pf CDPK2 function is not essential for the asexual proliferation of the parasite in vitro The mature male and female gametocytes of Pf CDPK2 KO parasites become round after induction. However, they fail to infect female Anopheles stephensi mosquitoes due to a defect(s) in male gametocyte exflagellation and possibly in female gametes. IMPORTANCE Despite reductions in the number of deaths it causes, malaria continues to be a leading infectious disease of the developing world. For effective control and elimination of malaria, multiple stages of the parasite need to be targeted. One such stage includes the transmission of the parasite to mosquitoes. Here, we demonstrate the successful knockout of Pf CDPK2, which was previously thought to be indispensable for parasite growth in red blood cells. The Pf CDPK2 KO parasites are incapable of establishing an infection in mosquitoes. Therefore, our study suggests that targeting Pf CDPK2 may be a good strategy to control malaria transmission in countries with high transmission. Moreover, molecular understanding of the signaling pathway of Pf CDPK2 may provide additional targets for malaria control. Copyright © 2017 Bansal et al.

Management of imported malaria in Europe

PubMed Central

2012-01-01

In this position paper, the European Society for Clinical Microbiology and Infectious Diseases, Study Group on Clinical Parasitology, summarizes main issues regarding the management of imported malaria cases. Malaria is a rare diagnosis in Europe, but it is a medical emergency. A travel history is the key to suspecting malaria and is mandatory in patients with fever. There are no specific clinical signs or symptoms of malaria although fever is seen in almost all non-immune patients. Migrants from malaria endemic areas may have few symptoms. Malaria diagnostics should be performed immediately on suspicion of malaria and the gold- standard is microscopy of Giemsa-stained thick and thin blood films. A Rapid Diagnostic Test (RDT) may be used as an initial screening tool, but does not replace urgent microscopy which should be done in parallel. Delays in microscopy, however, should not lead to delayed initiation of appropriate treatment. Patients diagnosed with malaria should usually be hospitalized. If outpatient management is preferred, as is the practice in some European centres, patients must usually be followed closely (at least daily) until clinical and parasitological cure. Treatment of uncomplicated Plasmodium falciparum malaria is either with oral artemisinin combination therapy (ACT) or with the combination atovaquone/proguanil. Two forms of ACT are available in Europe: artemether/lumefantrine and dihydroartemisinin/piperaquine. ACT is also effective against Plasmodium vivax, Plasmodium ovale, Plasmodium malariae and Plasmodium knowlesi, but these species can be treated with chloroquine. Treatment of persistent liver forms in P. vivax and P. ovale with primaquine is indicated after excluding glucose 6 phosphate dehydrogenase deficiency. There are modified schedules and drug options for the treatment of malaria in special patient groups, such as children and pregnant women. The potential for drug interactions and the role of food in the absorption of anti-malarials are important considerations in the choice of treatment. Complicated malaria is treated with intravenous artesunate resulting in a much more rapid decrease in parasite density compared to quinine. Patients treated with intravenous artesunate should be closely monitored for haemolysis for four weeks after treatment. There is a concern in some countries about the lack of artesunate produced according to Good Manufacturing Practice (GMP). PMID:22985344

A retrospective analysis of the protective efficacy of tafenoquine and mefloquine as prophylactic anti-malarials in non-immune individuals during deployment to a malaria-endemic area.

PubMed

Dow, Geoffrey S; McCarthy, William F; Reid, Mark; Smith, Bryan; Tang, Douglas; Shanks, G Dennis

2014-02-06

In 2000/2001, the Australian Defense Forces (ADF), in collaboration with SmithKline Beecham and the United States Army, conducted a field trial to evaluate the safety, tolerability and efficacy of tafenoquine and mefloquine/primaquine for the prophylaxis of malaria amongst non-immune Australian soldiers deployed to East Timor (now called Timor Leste) for peacekeeping operations. The lack of a concurrent placebo control arm prevented an internal estimate of the malaria attack rate and so the protective efficacy of the study regimens was not determined at the time. In a retrospective analysis of the trial results, the all species malaria attack rate was estimated for the prophylactic phase of the study which was defined as the period between administration of the first prophylactic dose and the first dose of post-deployment medication. First, the Plasmodium vivax attack rate was estimated during the prophylactic phase of the deployment by adjusting the observed P. vivax relapse rate during post-deployment to account for the known anti-relapse efficacies (or effectiveness) of the study medications (determined from prior studies). The all species malaria attack rate (P. vivax and Plasmodium falciparum) was then determined by adjusting the P. vivax attack rate based on the ratio of P. falciparum to P. vivax observed during prior ADF deployments to Timor Leste. This estimated all species malaria attack rate was then used as the 'constant estimated attack rate' in the calculation of the protective efficacy of tafenoquine and mefloquine during the prophylactic phase of the deployment. The estimated attack rate during the prophylactic phase of the study was determined to be 7.88%. The protective efficacies of tafenoquine and mefloquine, with corresponding 95% confidence intervals (95% CI), were determined to be 100% (93%-100%) and 100% (79%-100%) respectively. The protective efficacy of tafenoquine (200 mg per day for three days, followed by weekly 200 mg maintenance doses) is similar to that of the weekly standard of care (mefloquine, 250 mg).

A retrospective analysis of the protective efficacy of tafenoquine and mefloquine as prophylactic anti-malarials in non-immune individuals during deployment to a malaria-endemic area

PubMed Central

2014-01-01

Background In 2000/2001, the Australian Defense Forces (ADF), in collaboration with SmithKline Beecham and the United States Army, conducted a field trial to evaluate the safety, tolerability and efficacy of tafenoquine and mefloquine/primaquine for the prophylaxis of malaria amongst non-immune Australian soldiers deployed to East Timor (now called Timor Leste) for peacekeeping operations. The lack of a concurrent placebo control arm prevented an internal estimate of the malaria attack rate and so the protective efficacy of the study regimens was not determined at the time. Methods In a retrospective analysis of the trial results, the all species malaria attack rate was estimated for the prophylactic phase of the study which was defined as the period between administration of the first prophylactic dose and the first dose of post-deployment medication. First, the Plasmodium vivax attack rate was estimated during the prophylactic phase of the deployment by adjusting the observed P. vivax relapse rate during post-deployment to account for the known anti-relapse efficacies (or effectiveness) of the study medications (determined from prior studies). The all species malaria attack rate (P. vivax and Plasmodium falciparum) was then determined by adjusting the P. vivax attack rate based on the ratio of P. falciparum to P. vivax observed during prior ADF deployments to Timor Leste. This estimated all species malaria attack rate was then used as the ‘constant estimated attack rate’ in the calculation of the protective efficacy of tafenoquine and mefloquine during the prophylactic phase of the deployment. Results The estimated attack rate during the prophylactic phase of the study was determined to be 7.88%. The protective efficacies of tafenoquine and mefloquine, with corresponding 95% confidence intervals (95% CI), were determined to be 100% (93%-100%) and 100% (79%-100%) respectively. Conclusions The protective efficacy of tafenoquine (200 mg per day for three days, followed by weekly 200 mg maintenance doses) is similar to that of the weekly standard of care (mefloquine, 250 mg). PMID:24502679

Summary of anti-malarial prophylactic efficacy of tafenoquine from three placebo-controlled studies of residents of malaria-endemic countries.

PubMed

Dow, Geoffrey S; Liu, Jun; Lin, Gina; Hetzell, Brian; Thieling, Sarah; McCarthy, William F; Tang, Douglas; Smith, Bryan

2015-11-26

Tafenoquine is a long half-life primaquine analog being developed for malaria prophylaxis. The US Army recently performed a unified analysis of efficacy in preparation for a regulatory submission, utilizing legacy data from three placebo-controlled studies conducted in the late 1990s and early 2000s. The subjects were residents of Africa who were naturally exposed to Plasmodium falciparum for 12-26 weeks. The prophylactic efficacy of tafenoquine and mefloquine (included in some studies as a comparator) was calculated using incidence density among subjects who had completed the three-day loading doses of study drug, had at least one maintenance dose and had at least one blood smear assessed during the prophylactic period. The three placebo-controlled studies were analysed separately and then in two pooled analyses: one for tafenoquine versus placebo (three studies) and one for tafenoquine and mefloquine versus placebo (two studies). The pooled protective efficacy (PE) of a tafenoquine regimen with three daily loading doses plus weekly maintenance at 200-mg for 10 weeks or longer (referred to as 200-mg weekly hereafter) relative to placebo in three placebo-controlled studies was 93.1 % [95 % confidence interval (CI) 89.1-95.6 %; total N = 492]. The pooled PEs of regimens of tafenoquine 200-mg weekly and mefloquine 250-mg weekly relative to placebo in two placebo-controlled studies (total N = 519) were 93.5 % (95 % CI 88.6-96.2 %) and 94.5 % (95 % CI 88.7-97.3 %), respectively. Three daily loading plus weekly maintenance doses of 50- and 100-mg, but not 25-mg, exhibited similar PEs. The PEs of tafenoquine regimens of a three-day loading dose at 400-mg with and without follow-up weekly maintenance doses at 400-mg were 93.7 % (95 % CI 85.4-97.3 %) and 81.0 % (95 % CI 66.8-89.1 %), respectively. Tafenoquine provided the same level of prophylactic efficacy as mefloquine in residents of Africa. These data support the prophylactic efficacy of tafenoquine and mefloquine that has already been demonstrated in the intended malaria naive population.

Glucose-6-phosphate dehydrogenase deficiency among malaria suspects attending Gambella hospital, southwest Ethiopia.

PubMed

Tsegaye, Arega; Golassa, Lemu; Mamo, Hassen; Erko, Berhanu

2014-11-18

Glucose-6-phosphate dehydrogenase deficiency (G6PDd) is widespread across malaria endemic regions. G6PD-deficient individuals are at risk of haemolysis when exposed, among other agents, to primaquine and tafenoquine, which are capable of blocking malaria transmission by killing Plasmodium falciparum gametocytes and preventing Plasmodium vivax relapses by targeting hypnozoites. It is evident that no measures are currently in place to ensure safe delivery of these drugs within the context of G6PDd risk. Thus, determining G6PDd prevalence in malarious areas would contribute towards avoiding possible complications in malaria elimination using the drugs. This study, therefore, was aimed at determining G6PDd prevalence in Gambella hospital, southwest Ethiopia, using CareStart™ G6PDd fluorescence spot test. Venous blood samples were collected from febrile patients (n = 449) attending Gambella hospital in November-December 2013. Malaria was diagnosed using blood films and G6PDd was screened using CareStart™ G6PDd screening test (Access Bio, New Jersey, USA). Haematological parameters were also measured. The association of G6PD phenotype with sex, ethnic group and malaria smear positivity was tested. Malaria prevalence was 59.2% (96.6% of the cases being P. falciparum mono infections). Totally 33 participants (7.3%) were G6PD-deficient with no significant difference between the sexes. The chance of being G6PD-deficient was significantly higher for the native ethnic groups (Anuak and Nuer) compared to the 'highlanders'/settlers (odds ratio (OD) = 3.9, 95% confidence interval (CI) 0.481-31.418 for Anuak vs 'highlanders'; OD = 4.9, 95% CI 0.635-38.00 for Nuer vs 'highlanders'). G6PDd prevalence among the Nuer (14.3%) was significantly higher than that for the Anuak (12.0%). G6PDd prevalence in the area is substantial with 30 (90.9%) of the 33 deficient individuals having malaria suggesting the non-protective role of the disorder at least from clinical malaria. The indigenous Nilotic people tend to have a higher chance of being G6PD-deficient as 32 (96.9%) of the total 33 cases occurred among them.

Strain-Specific Protective Effect of the Immunity Induced by Live Malarial Sporozoites under Chloroquine Cover

PubMed Central

Wijayalath, Wathsala; Cheesman, Sandra; Tanabe, Kazuyuki; Handunnetti, Shiroma; Carter, Richard; Pathirana, Sisira

2012-01-01

The efficacy of a whole-sporozoite malaria vaccine would partly be determined by the strain-specificity of the protective responses against malarial sporozoites and liver-stage parasites. Evidence from previous reports were inconsistent, where some studies have shown that the protective immunity induced by irradiated or live sporozoites in rodents or humans were cross-protective and in others strain-specific. In the present work, we have studied the strain-specificity of live sporozoite-induced immunity using two genetically and immunologically different strains of Plasmodium cynomolgi, Pc746 and PcCeylon, in toque monkeys. Two groups of monkeys were immunized against live sporozoites of either the Pc746 (n = 5), or the PcCeylon (n = 4) strain, by the bites of 2–4 sporozoite-infected Anopheles tessellates mosquitoes per monkey under concurrent treatments with chloroquine and primaquine to abrogate detectable blood infections. Subsequently, a group of non-immunized monkeys (n = 4), and the two groups of immunized monkeys were challenged with a mixture of sporozoites of the two strains by the bites of 2–5 infective mosquitoes from each strain per monkey. In order to determine the strain-specificity of the protective immunity, the proportions of parasites of the two strains in the challenge infections were quantified using an allele quantification assay, Pyrosequencing™, based on a single nucleotide polymorphism (SNP) in the parasites’ circumsporozoite protein gene. The Pyrosequencing™ data showed that a significant reduction of parasites of the immunizing strain in each group of strain-specifically immunized monkeys had occurred, indicating a stronger killing effect on parasites of the immunizing strain. Thus, the protective immunity developed following a single, live sporozoite/chloroquine immunization, acted specifically against the immunizing strain and was, therefore, strain-specific. As our experiment does not allow us to determine the parasite stage at which the strain-specific protective immunity is directed, it is possible that the target of this immunity could be either the pre-erythrocytic stage, or the blood-stage, or both. PMID:23029282

Prevalence of G6PD deficiency in selected populations from two previously high malaria endemic areas of Sri Lanka

PubMed Central

Kapilananda, G. M. G.; Samarakoon, Dilhani; Maddevithana, Sashika; Wijesundera, Sulochana; Goonaratne, Lallindra V.; Karunaweera, Nadira D.

2017-01-01

Glucose-6-Phosphate Dehydrogenase (G6PD) enzyme deficiency is known to offer protection against malaria and an increased selection of mutant genes in malaria endemic regions is expected. However, anti-malarial drugs such as primaquine can cause haemolytic anaemia in persons with G6PD deficiency. We studied the extent of G6PD deficiency in selected persons attending Teaching Hospitals of Anuradhapura and Kurunegala, two previously high malaria endemic districts in Sri Lanka. A total of 2059 filter-paper blood spots collected between November 2013 and June 2014 were analysed for phenotypic G6PD deficiency using the modified WST-8/1-methoxy PMS method. Each assay was conducted with a set of controls and the colour development assessed visually as well as with a microplate reader at OD450-630nm. Overall, 142/1018 (13.95%) and 83/1041 (7.97%) were G6PD deficient in Anuradhapura and Kurunegala districts respectively. The G6PD prevalence was significantly greater in Anuradhapura when compared to Kurunegala (P<0.0001). Surprisingly, females were equally affected as males in each district: 35/313 (11.18%) males and 107/705 (15.18%) females were affected in Anuradhapura (P = 0.089); 25/313 (7.99%) males and 58/728 (7.97%) females were affected in Kurunegala (P = 0.991). Prevalence was greater among females in Anuradhapura than in Kurunegala (P<0.05), while no such difference was observed between the males (P>0.05). Severe deficiency (<10% normal) was seen among 28/1018 (2.75%) in Anuradhapura (7 males; 21 females) and 17/1041 (1.63%) in Kurunegala (7 males; 10 females). Enzyme activity between 10–30% was observed among 114/1018 (11.20%; 28 males; 86 females) in Anuradhapura while it was 66/1041 (6.34%; 18 males; 48 females) in Kurunegala. Screening and educational programmes for G6PD deficiency are warranted in these high risk areas irrespective of gender for the prevention of disease states related to this condition. PMID:28152025

Prevalence of G6PD deficiency in selected populations from two previously high malaria endemic areas of Sri Lanka.

PubMed

Gunawardena, Sharmini; Kapilananda, G M G; Samarakoon, Dilhani; Maddevithana, Sashika; Wijesundera, Sulochana; Goonaratne, Lallindra V; Karunaweera, Nadira D

2017-01-01

Glucose-6-Phosphate Dehydrogenase (G6PD) enzyme deficiency is known to offer protection against malaria and an increased selection of mutant genes in malaria endemic regions is expected. However, anti-malarial drugs such as primaquine can cause haemolytic anaemia in persons with G6PD deficiency. We studied the extent of G6PD deficiency in selected persons attending Teaching Hospitals of Anuradhapura and Kurunegala, two previously high malaria endemic districts in Sri Lanka. A total of 2059 filter-paper blood spots collected between November 2013 and June 2014 were analysed for phenotypic G6PD deficiency using the modified WST-8/1-methoxy PMS method. Each assay was conducted with a set of controls and the colour development assessed visually as well as with a microplate reader at OD450-630nm. Overall, 142/1018 (13.95%) and 83/1041 (7.97%) were G6PD deficient in Anuradhapura and Kurunegala districts respectively. The G6PD prevalence was significantly greater in Anuradhapura when compared to Kurunegala (P<0.0001). Surprisingly, females were equally affected as males in each district: 35/313 (11.18%) males and 107/705 (15.18%) females were affected in Anuradhapura (P = 0.089); 25/313 (7.99%) males and 58/728 (7.97%) females were affected in Kurunegala (P = 0.991). Prevalence was greater among females in Anuradhapura than in Kurunegala (P<0.05), while no such difference was observed between the males (P>0.05). Severe deficiency (<10% normal) was seen among 28/1018 (2.75%) in Anuradhapura (7 males; 21 females) and 17/1041 (1.63%) in Kurunegala (7 males; 10 females). Enzyme activity between 10-30% was observed among 114/1018 (11.20%; 28 males; 86 females) in Anuradhapura while it was 66/1041 (6.34%; 18 males; 48 females) in Kurunegala. Screening and educational programmes for G6PD deficiency are warranted in these high risk areas irrespective of gender for the prevention of disease states related to this condition.

Sub-Saharan red cell antigen phenotypes and glucose-6-phosphate dehydrogenase deficiency variants in French Guiana.

PubMed

Petit, Florence; Bailly, Pascal; Chiaroni, Jacques; Mazières, Stéphane

2016-06-07

The treatment of Plasmodium vivax infections requires the use of primaquine, which can lead to severe haemolysis in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. However, most of the Latin American countries, which are still endemic for vivax malaria, lack information on the distribution of G6PD deficiency (G6PDd). No survey has been performed so far in French Guiana. Herein, 80 individuals of the French Guianan Noir Marron population were scrutinized for red cell surface antigens of six blood group systems (ABO, Rh, Kell, Kidd, Duffy and MNS) and G6PD genetic polymorphisms. First, the sub-Saharan origin of the red cell phenotypes was assessed in relation with the literature. Then, given that the main sub-Saharan G6PDd variants are expected to be encountered, only the G6PD sequences of exons 4, 5, 6 and 9 were screened. This work aims at appraising the G6PD gene variation in this population, and thus, contributing to the G6PD piecemeal information in Latin America. Ninety-seven percent (97 %) of the red cells are Fy(a- b-), either D+ C- E- c+ e+ or D+ C+ E- c+ e+ and 44 % exhibited the Fya-/Jkb-/S- combined phenotype. Noteworthy is the detection of the G6PD(Val68Met) variant characterized by c.202G > A transition, G6PD(Asn126Asp) variant characterized by c.376A>G transition and G6PD(Asp181Val) variant characterized by c.542A>T transversion of the G6PD gene in 22.5 % of the sample, characteristic of the A(-(202)), A and Santamaria G6PDd variants, respectively. French Guianan Noir Marron population represents a pool of Rh-D antigen positive, Duffy-negative and G6PD-deficient erythrocytes, the latter accounting for one in every eight persons. The present study provides the first community-based estimation of the frequency of G6PDd polymorphisms in French Guiana. These results contribute to the G6PD genetic background information puzzle in Latin America.

Malaria in the Greater Mekong Subregion: Heterogeneity and Complexity

PubMed Central

Cui, Liwang; Yan, Guiyun; Sattabongkot, Jetsumon; Cao, Yaming; Chen, Bin; Chen, Xiaoguang; Fan, Qi; Fang, Qiang; Jongwutiwes, Somchai; Parker, Daniel; Sirichaisinthop, Jeeraphat; Kyaw, Myat Phone; Su, Xin-zhuan; Yang, Henglin; Yang, Zhaoqing; Wang, Baomin; Xu, Jianwei; Zheng, Bin; Zhong, Daibin; Zhou, Guofa

2011-01-01

The Greater Mekong Subregion (GMS), comprised of six countries including Cambodia, China's Yunnan Province, Lao PDR, Myanmar (Burma), Thailand and Vietnam, is one of the most threatening foci of malaria. Since the initiation of the WHO's Mekong Malaria Program a decade ago, malaria situation in the GMS has greatly improved, reflected in the continuous decline in annual malaria incidence and deaths. However, as many nations are moving towards malaria elimination, the GMS nations still face great challenges. Malaria epidemiology in this region exhibits enormous geographical heterogeneity with Myanmar and Cambodia remaining high-burden countries. Within each country, malaria distribution is also patchy, exemplified by ‘border malaria’ and ‘forest malaria’ with high transmission occurring along international borders and in forests or forest fringes, respectively. ‘Border malaria’ is extremely difficult to monitor, and frequent malaria introductions by migratory human populations constitute a major threat to neighboring, malaria-eliminating countries. Therefore, coordination between neighboring countries is essential for malaria elimination from the entire region. In addition to these operational difficulties, malaria control in the GMS also encounters several technological challenges. Contemporary malaria control measures rely heavily on effective chemotherapy and insecticide control of vector mosquitoes. However, the spread of multidrug resistance and potential emergence of artemisinin resistance in Plasmodium falciparum make resistance management a high priority in the GMS. This situation is further worsened by the circulation of counterfeit and substandard artemisinin-related drugs. In most endemic areas of the GMS, P. falciparum and P. vivax coexist, and in recent malaria control history, P. vivax has demonstrated remarkable resilience to control measures. Deployment of the only registered drug (primaquine) for the radical cure of vivax malaria is severely undermined due to high prevalence of glucose-6-phosphate dehydrogenase deficiency in target human populations. In the GMS, the dramatically different ecologies, diverse vector systems, and insecticide resistance render traditional mosquito control less efficient. Here we attempt to review the changing malaria epidemiology in the GMS, analyze the vector systems and patterns of malaria transmission, and identify the major challenges the malaria control community faces on its way to malaria elimination. PMID:21382335

Frequency of G6PD Mediterranean in individuals with and without malaria in Southern Pakistan.

PubMed

Moiz, Bushra; Arshad, Haroon Muhammad; Raheem, Ahmed; Hayat, Hasan; Karim Ghanchi, Najia; Beg, M Asim

2017-10-24

Pakistan has an estimated annual burden of 1.5 million malaria cases. The current situation calls for an effective malaria control and eradication programme in this country. Currently, primaquine is an attractive option for eliminating reservoirs of Plasmodium vivax hypnozoites and killing gametocytes of Plasmodium falciparum. However, this drug causes haemolysis in individuals who are glucose-6-phosphate (G6PD) deficient. It is important to map G6PD deficiency and malaria distribution in Pakistan to design an effective malaria eradication regimen. Frequency of G6PD deficiency (G6PDd) in malaria patients has not been reported from Pakistan in any meaningful way. The purpose of this study was to evaluate the frequency of G6PD c.563C>T (G6PD Mediterranean) in male individuals with and without falciparum malaria. Two hundred and ten archived DNA samples from males (110 from falciparum malaria patients and 100 from healthy individuals) were utilized in this study. Healthy blood donors were selected based on stringent pre-defined criteria. Patients were confirmed for malaria parasites on microscopy and or immune chromatographic assay detecting P. falciparum histidine-rich protein 2. Parasitaemia was also computed. DNA samples were tested for G6PD c.563C>T mutation through PCR-RFLP according to the previously defined protocol and its allelic frequency was computed. G6PD c.563C>T was observed in four of 110 patients with falciparum malaria and in two of 100 healthy donors. Mean (± SD) haemoglobin, median (IQR) platelet and median (IQR) parasite count in G6PD-deficient malaria-patients were 8.9 ± 0.9 g/dL, 124 × 109/L (IQR 32, 171) and 57,920/μL of blood (IQR 12,920, 540,000) respectively. Cumulative allelic frequency for G6PD 563c.C>T was 0.0285 detected in 6 of 210 X-chromosomes in Southern Pakistan. Frequency for this G6PD allele was 0.0364 in malaria-patients and 0.0200 in healthy individuals. Large studies including females are needed to elucidate the true burden of G6PDd in malaria-endemic areas. The information will enable local health policy makers to design effective strategies for eliminating malaria form this region.

Evaluation of case management of uncomplicated malaria in Haiti: a national health facility survey, 2012.

PubMed

Landman, Keren Z; Jean, Samuel E; Existe, Alexandre; Akom, Eniko E; Chang, Michelle A; Lemoine, Jean Frantz; Mace, Kimberly E

2015-10-09

Malaria is a public health concern in Haiti, although there are limited data on its burden and case management. National malaria guidelines updated in 2012 recommend treatment with chloroquine and primaquine. In December 2012, a nationally-representative cross-sectional survey of health facilities (HFs) was conducted to determine malaria prevalence among febrile outpatients and malaria case management quality at baseline before scale-up of diagnostics and case management training. Among all 833 HFs nationwide, 30 were selected randomly, in proportion to total HFs per region, for 2-day evaluations. Survey teams inventoried HF material and human resources. Outpatients of all ages were screened for temperature >37.5 °C or history of fever; those without severe symptoms were consented and enrolled. Providers evaluated and treated enrolled patients according to HF standards; the survey teams documented provider-ordered diagnostic tests and treatment decisions. Facility-based test results [microscopy and malaria rapid diagnostic tests (RDTs)] were collected from HF laboratories. Blood smears for gold-standard microscopy, and dried blood spots for polymerase chain reaction (PCR) were obtained. Malaria diagnostic capacity, defined as completing a test for an enrolled patient or having adequate resources for RDTs or microscopy, was present in 11 (37 %) HFs. Among 459 outpatients screened, 257 (56 %) were febrile, of which 193 (75 %) were eligible, and 153 (80 %) were enrolled. Among 39 patients with facility-level malaria test results available on the survey day, 11 (28 %) were positive, of whom 6 (55 %) were treated with an anti-malarial. Twenty-seven (95 %) of the 28 patients testing negative were not treated with an anti-malarial. Of 114 patients without test results available, 35 (31 %) were presumptively treated for malaria. Altogether, 42 patients were treated with an anti-malarial, one (2 %) according to Haiti's 2012 guidelines. Of 140 gold-standard smears, none were positive, although one patient tested positive by PCR, a more sensitive technique. The national prevalence of malaria among febrile outpatients is estimated to be 0.5 % (95 % confidence interval 0-1.7 %). Malaria is an uncommon cause of fever in Haitian outpatients, and limited, often inaccurate, diagnostic capacity at baseline contributes to over diagnosis. Scale-up of diagnostics and training on new guidelines should improve malaria diagnosis and treatment in Haiti.

Cryopreservation of glucose-6-phosphate dehydrogenase activity inside red blood cells: developing a specimen repository in support of development and evaluation of glucose-6-phosphate dehydrogenase deficiency tests

PubMed Central

2013-01-01

Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common human enzyme deficiency. It is characterized by abnormally low levels of G6PD activity. Individuals with G6PD deficiency are at risk of undergoing acute haemolysis when exposed to 8‒aminoquinoline-based drugs, such as primaquine. For this reason it is imperative to identify individuals with G6PD deficiency prior to administering these anti-malarial drugs. There is a need for the development and evaluation of point-of-care G6PD deficiency screening tests suitable for areas of the developing world where malarial treatments are frequently administered. The development and evaluation of new G6PD tests will be greatly assisted with the availability of specimen repositories. Methods Cryopreservation of erythrocytes was evaluated as a means to preserve G6PD activity. Blood specimens from 31 patients including ten specimens with normal G6PD activity, three with intermediate activity, and 18 with deficient activity were cryopreserved for up to six months. Results Good correlation in G6PD activity between fresh and cryopreserved specimens (R2 = 0.95). The cryopreserved specimens show an overall small drop in mean G6PD activity of 0.23 U/g Hb (P=0.23). Cytochemical staining showed that intracellular G6PD activity distribution within the red blood cell populations is preserved during cryopreservation. Furthermore, the mosaic composition of red blood cells in heterozygous women is also preserved for six months or more. The fluorescent spot and the BinaxNOW qualitative tests for G6PD deficiency also showed high concordance in G6PD status determination between cryopreserved specimens and fresh specimens. Conclusions A methodology for establishing a specimen panel for evaluation of G6PD tests is described. The approach is similar to that used in several malaria research facilities for the cryopreservation of parasites in clinical specimens and axenic cultures. Specimens stored in this manner will aid both the development and evaluation of current and emerging G6PD tests. The availability of G6PD tests is a critical bottleneck to broader access to drugs that confer radical cure of Plasmodium vivax, a requirement for elimination of malaria. PMID:23961874

Prevalence, genetic variants and clinical implications of G-6-PD deficiency in Burkina Faso: a systematic review.

PubMed

Ouattara, Abdoul Karim; Yameogo, Pouiré; Traore, Lassina; Diarra, Birama; Assih, Maléki; Compaore, Tegwindé Rébéca; Obiri-Yeboah, Dorcas; Soubeiga, Serge Théophile; Djigma, Florencia Wendkuuni; Simpore, Jacques

2017-11-23

It is now well-known that some antimalarials such as primaquine may induce severe hemolytic anemia in people with G-6-PD deficiency. Antimalarial drug prescriptions must, therefore take into account the patient's G-6-PD status in malaria endemic areas such as Burkina Faso, where the prevalence of this genetic abnormality is relatively high. Although great clinical heterogeneity is observed depending on the molecular nature of the deficiency and the residual enzyme activity in the red blood cell, there is very poor data on the prevalence of G-6-PD deficiency and the distribution of involved genetic variants in Burkina Faso. In this systematic review, we present a synthesis of the various studies carried out on the G-6-PD deficiency in Burkina Faso in order to determine its prevalence, probable distribution of the genetic variants involved and their clinical implications for a national systematic screening policy among the groups most vulnerable to malaria. A systematic review was carried out to analyze available published data on the prevalence, phenotypes and mutations responsible for G-6-PD deficiency in Burkina Faso. The key words used were "G-6-PD deficiency AND Burkina Faso" or "Déficit en G-6-PD AND Burkina Faso" in French. To identify the relevant articles, two independent reviewers reviewed the titles, abstracts and the full text of the selected papers. An average prevalence of 16.6% (183/1100; CI 95%: 0.145-0.190) and 6.5% (69/1066; CI 95%: 0.051-0.081) of G-6-PD deficiency was found respectively in men and women in this systematic review. Although the predominance (99.8% of G-6-PD deficient cases) of 202A/376G G-6-PD A- variant, the Santamaria and Betica Selma variants were identified in Burkina Faso. Independently of the method used, the enzymatic deficiency was significantly higher in males (2.5-20.5%) compared to females (3.3-12.3%). This systematic review suggests that despite the ubiquity of the 202A/376G G-6-PD A- variant in Burkina Faso, it will be necessary to consider the Santamaria and Betica Selma variants although their frequencies remain to be specified. A systematic screening of the G-6-PD deficiency is also needed to prevent the occurrence of iatrogenic hemolytic accidents.

Dihydroartemisinin–piperaquine resistance in Plasmodium falciparum malaria in Cambodia: a multisite prospective cohort study

PubMed Central

Amaratunga, Chanaki; Lim, Pharath; Suon, Seila; Sreng, Sokunthea; Mao, Sivanna; Sopha, Chantha; Sam, Baramey; Dek, Dalin; Try, Vorleak; Amato, Roberto; Blessborn, Daniel; Song, Lijiang; Tullo, Gregory S; Fay, Michael P; Anderson, Jennifer M; Tarning, Joel; Fairhurst, Rick M

2016-01-01

Background Artemisinin resistance in Plasmodium falciparum threatens to reduce the efficacy of artemisinin combination therapies (ACTs), thus compromising global efforts to eliminate malaria. Recent treatment failures with dihydroartemisinin-piperaquine, the current first-line ACT in Cambodia, suggest that piperaquine resistance may be emerging in this country. We explored the relation between artemisinin resistance and dihydroartemisinin–piperaquine failures, and sought to confirm the presence of piperaquine-resistant P falciparum infections in Cambodia. Methods In this prospective cohort study, we enrolled patients aged 2–65 years with uncomplicated P falciparum malaria in three Cambodian provinces: Pursat, Preah Vihear, and Ratanakiri. Participants were given standard 3-day courses of dihydroartemisinin–piperaquine. Peripheral blood parasite densities were measured until parasites cleared and then weekly to 63 days. The primary outcome was recrudescent P falciparum parasitaemia within 63 days. We measured piperaquine plasma concentrations at baseline, 7 days, and day of recrudescence. We assessed phenotypic and genotypic markers of drug resistance in parasite isolates. The study is registered with ClinicalTrials.gov, number NCT01736319. Findings Between Sept 4, 2012, and Dec 31, 2013, we enrolled 241 participants. In Pursat, where artemisinin resistance is entrenched, 37 (46%) of 81 patients had parasite recrudescence. In Preah Vihear, where artemisinin resistance is emerging, ten (16%) of 63 patients had recrudescence and in Ratanakiri, where artemisinin resistance is rare, one (2%) of 60 patients did. Patients with recrudescent P falciparum infections were more likely to have detectable piperaquine plasma concentrations at baseline compared with non-recrudescent patients, but did not differ significantly in age, initial parasite density, or piperaquine plasma concentrations at 7 days. Recrudescent parasites had a higher prevalence of kelch13 mutations, higher piperaquine 50% inhibitory concentration (IC50) values, and lower mefloquine IC50 values; none had multiple pfmdr1 copies, a genetic marker of mefloquine resistance. Interpretation Dihydroartemisinin–piperaquine failures are caused by both artemisinin and piperaquine resistance, and commonly occur in places where dihydroartemisinin–piperaquine has been used in the private sector. In Cambodia, artesunate plus mefloquine may be a viable option to treat dihydroartemisinin–piperaquine failures, and a more effective first-line ACT in areas where dihydroartemisinin–piperaquine failures are common. The use of single low-dose primaquine to eliminate circulating gametocytes is needed in areas where artemisinin and ACT resistance is prevalent. Funding National Institute of Allergy and Infectious Diseases. PMID:26774243

Genetic diversity and natural selection of Plasmodium vivax multi-drug resistant gene (pvmdr1) in Mesoamerica.

PubMed

González-Cerón, Lilia; Montoya, Alberto; Corzo-Gómez, Josselin C; Cerritos, Rene; Santillán, Frida; Sandoval, Marco A

2017-07-01

The Plasmodium vivax multidrug resistant 1 gene (pvmdr1) codes for a transmembrane protein of the parasite's digestive vacuole. It is likely that the pvmdr1 gene mutations occur at different sites by convergent evolution. In here, the genetic variation of pvmdr1 at three sites of the Mesoamerican region was studied. Since 1950s, malarious patients of those areas have been treated only with chloroquine and primaquine. Blood samples from patients infected with P. vivax were obtained in southern Mexico (SMX), in the Northwest (NIC-NW) and in the northeast (NIC-NE) of Nicaragua. Genomic DNA was obtained and fragments of pvmdr1 were amplified and sequenced. The nucleotide and amino acid changes as well as the haplotype frequency in pvmdr1 were determined per strain and per geographic site. The sequences of pvmdr1 obtained from the studied regions were compared with homologous sequences from the GenBank database to explore the P. vivax genetic structure. In 141 parasites, eight nucleotide changes (two changes were synonymous and other six were nonsynonymous) were detected in 1536 bp. The PvMDR1 amino acid changes Y976F, F1076FL were predominant in endemic parasites from NIC-NE and outbreak parasites in NIC-NW but absent in SMX. Thirteen haplotypes were resolved, and found to be closely related, but their frequency at each geographic site was different (P = 0.0001). The pvmdr1 codons 925-1083 gene fragment showed higher genetic and haplotype diversity in parasites from NIC-NE than the other areas outside Latin America. The haplotype networks suggested local diversification of pvmdr1 and no significant departure from neutrality. The F ST values were low to moderate regionally, but high between NIC-NE or NIC-NW and other regions inside and outside Latin America. The pvmdr1 gene might have diversified recently at regional level. In the absence of significant natural, genetic drift might have caused differential pvmdr1 haplotype frequencies at different geographic sites in Mesoamerica. A very recent expansion of divergent pvmdr1 haplotypes in NIC-NE/NIC-NW produced high differentiation between these and parasites from other sites including SMX. These data are useful to set a baseline for epidemiological surveillance.

Clinical complications of G6PD deficiency in Latin American and Caribbean populations: systematic review and implications for malaria elimination programmes

PubMed Central

2014-01-01

Background Although G6PDd individuals are generally asymptomatic throughout their life, the clinical burden of this genetic condition includes a range of haematological conditions, including acute haemolytic anaemia (AHA), neonatal jaundice (NNJ) and chronic non-sphaerocytic anaemia (CNSA). In Latin America (LA), the huge knowledge gap regarding G6PDd is related to the scarce understanding of the burden of clinical manifestation underlying G6PDd carriage. The aim of this work was to study the clinical significance of G6PDd in LA and the Caribbean region through a systematic review. Methods A systematic search of the published literature was undertaken in August 2013. Bibliographies of manuscripts were also searched and additional references were identified. Only original research was included. All study designs were included, as long as any clinical information was present. Studies were eligible for inclusion if they reported clinical information from populations living in LA or Caribbean countries or about migrants from these countries living in countries outside this continent. Results The Medline search generated 487 papers, and the LILACS search identified 140 papers. After applying the inclusion criteria, 100 original papers with any clinical information on G6PDd in LA were retrieved. Additionally, 16 articles were included after reading the references from these papers. These 116 articles reported data from 18 LA and Caribbean countries. The major clinical manifestations reported from LA countries were those related to AHA, namely drug-induced haemolysis. Most of the published works regarding drug-induced haemolysis in LA referred to haemolytic crises in P. vivax malaria patients during the course of the treatment with primaquine (PQ). Favism, infection-induced haemolysis, NNJ and CNSA appear to play only a minor public health role in this continent. Conclusion Haemolysis in patients using PQ seems to be the major clinical manifestation of G6PDd in LA and contributes to the morbidity of P. vivax infection in this continent, although the low number of reported cases, which could be linked to under-reporting of complications. These results support the need for better strategies to diagnose and manage G6PDd in malaria field conditions. Additionally, Malaria Control Programmes in LA should not overlook this condition in their national guidelines. PMID:24568147

Multiple Origins of Mutations in the mdr1 Gene—A Putative Marker of Chloroquine Resistance in P. vivax

PubMed Central

Schousboe, Mette L.; Ranjitkar, Samir; Rajakaruna, Rupika S.; Amerasinghe, Priyanie H.; Morales, Francisco; Pearce, Richard; Ord, Rosalyn; Leslie, Toby; Rowland, Mark; Gadalla, Nahla B.; Konradsen, Flemming; Bygbjerg, Ib C.; Roper, Cally; Alifrangis, Michael

2015-01-01

Background Chloroquine combined with primaquine has been the recommended antimalarial treatment of Plasmodium vivax malaria infections for six decades but the efficacy of this treatment regimen is threatened by chloroquine resistance (CQR). Single nucleotide polymorphisms (SNPs) in the multidrug resistance gene, Pvmdr1 are putative determinants of CQR but the extent of their emergence at population level remains to be explored. Objective In this study we describe the prevalence of SNPs in the Pvmdr1 among samples collected in seven P. vivax endemic countries and we looked for molecular evidence of drug selection by characterising polymorphism at microsatellite (MS) loci flanking the Pvmdr1 gene. Methods We examined the prevalence of SNPs in the Pvmdr1 gene among 267 samples collected from Pakistan, Afghanistan, Sri Lanka, Nepal, Sudan, São Tomé and Ecuador. We measured and diversity in four microsatellite (MS) markers flanking the Pvmdr1 gene to look evidence of selection on mutant alleles. Results SNP polymorphism in the Pvmdr1 gene was largely confined to codons T958M, Y976F and F1076L. Only 2.4% of samples were wildtype at all three codons (TYF, n = 5), 13.3% (n = 28) of the samples were single mutant MYF, 63.0% of samples (n = 133) were double mutant MYL, and 21.3% (n = 45) were triple mutant MFL. Clear geographic differences in the prevalence of these Pvmdr mutation combinations were observed. Significant linkage disequilibrium (LD) between Pvmdr1 and MS alleles was found in populations sampled in Ecuador, Nepal and Sri Lanka, while significant LD between Pvmdr1 and the combined 4 MS locus haplotype was only seen in Ecuador and Sri Lanka. When combining the 5 loci, high level diversity, measured as expected heterozygosity (He), was seen in the complete sample set (He = 0.99), while He estimates for individual loci ranged from 0.00–0.93. Although Pvmdr1 haplotypes were not consistently associated with specific flanking MS alleles, there was significant differentiation between geographic sites which could indicate directional selection through local drug pressure. Conclusions Our observations suggest that Pvmdr1 mutations emerged independently on multiple occasions even within the same population. In Sri Lanka population analysis at multiple sites showed evidence of local selection and geographical dispersal of Pvmdr1 mutations between sites. PMID:26539821

The Impact of Phenotypic and Genotypic G6PD Deficiency on Risk of Plasmodium vivax Infection: A Case-Control Study amongst Afghan Refugees in Pakistan

PubMed Central

Leslie, Toby; Briceño, Marnie; Mayan, Ismail; Mohammed, Nasir; Klinkenberg, Eveline; Sibley, Carol Hopkins; Whitty, Christopher J. M.; Rowland, Mark

2010-01-01

Background The most common form of malaria outside Africa, Plasmodium vivax, is more difficult to control than P. falciparum because of the latent liver hypnozoite stage, which causes multiple relapses and provides an infectious reservoir. The African (A−) G6PD (glucose-6-phosphate dehydrogenase) deficiency confers partial protection against severe P. falciparum. Recent evidence suggests that the deficiency also confers protection against P. vivax, which could explain its wide geographical distribution in human populations. The deficiency has a potentially serious interaction with antirelapse therapies (8-aminoquinolines such as primaquine). If the level of protection was sufficient, antirelapse therapy could become more widely available. We therefore tested the hypothesis that G6PD deficiency is protective against vivax malaria infection. Methods and Findings A case-control study design was used amongst Afghan refugees in Pakistan. The frequency of phenotypic and genotypic G6PD deficiency in individuals with vivax malaria was compared against controls who had not had malaria in the previous two years. Phenotypic G6PD deficiency was less common amongst cases than controls (cases: 4/372 [1.1%] versus controls 42/743 [5.7%]; adjusted odds ratio [AOR] 0.18 [95% confidence interval (CI) 0.06–0.52], p = 0.001). Genetic analysis demonstrated that the G6PD deficiency allele identified (Mediterranean type) was associated with protection in hemizygous deficient males (AOR = 0.12 [95% CI 0.02–0.92], p = 0.041). The deficiency was also protective in females carrying the deficiency gene as heterozygotes or homozygotes (pooled AOR = 0.37 [95% CI 0.15–0.94], p = 0.037). Conclusions G6PD deficiency (Mediterranean type) conferred significant protection against vivax malaria infection in this population whether measured by phenotype or genotype, indicating a possible evolutionary role for vivax malaria in the selective retention of the G6PD deficiency trait in human populations. Further work is required on the genotypic protection associated with other types of G6PD deficiency and on developing simple point-of-care technologies to detect it before administering antirelapse therapy. Please see later in the article for the Editors' Summary PMID:20520804

Glucose-6-phosphate dehydrogenase deficiency prevalence and genetic variants in malaria endemic areas of Colombia.

PubMed

Valencia, Sócrates Herrera; Ocampo, Iván Darío; Arce-Plata, María Isabel; Recht, Judith; Arévalo-Herrera, Myriam

2016-05-26

Glucose 6-phosphate dehydrogenase (G6PD) is an enzyme involved in prevention of cellular oxidative damage, particularly protecting erythrocytes from haemolysis. An estimated 400 million people present variable degrees of inherited G6PD deficiency (G6PDd) which puts them at risk for developing haemolysis triggered by several risk factors including multiple drugs and certain foods. Primaquine (PQ) is a widely used anti-malarial drug that can trigger haemolysis in individuals with G6PDd. Intensification of malaria control programmes worldwide and particularly malaria elimination planning in some regions recommend a more extensive use of PQ and related drugs in populations with different G6PDd prevalence. This a preliminary study to assess the prevalence of G6PDd in representative malaria endemic areas of Colombia by measuring G6PD phonotype and genotypes. Volunteers (n = 426) from four malaria endemic areas in Colombia (Buenaventura, Tumaco, Tierralta and Quibdo) were enrolled. Blood samples were drawn to evaluate G6PD enzymatic activity by using a quantitative G6PD test and a subset of samples was analysed by PCR-RFLP to determine the frequency of the three most common G6PD genotypic variants: A-, A+ and Mediterranean. A total of 28 individuals (6.56 %) displayed either severe or intermediate G6PDd. The highest prevalence (3.51 %) was in Buenaventura, whereas G6PDd prevalence was lower (<1 %) in Tierralta and Quibdo. G6PD A alleles were the most frequent (15.23 %) particularly in Buenaventura and Tumaco. Overall, a high frequency of G6PD A- genotype, followed by A+ genotype was found in the analysed population. G6PDd based on enzymatic activity as well as G6PD A allelic variants were found in malaria-endemic populations on the Pacific coast of Colombia, where most of malaria cases are caused by Plasmodium vivax infections. These infections are treated for 14 days with PQ, however there are no official reports of PQ-induced haemolytic crises. Further assessment of G6PDd prevalence in malaria endemic areas in Colombia is crucial in view of possible mass drug administration for malaria elimination in these regions, as well as implementation of appropriate G6PDd diagnostic methods.

Cryopreservation of glucose-6-phosphate dehydrogenase activity inside red blood cells: developing a specimen repository in support of development and evaluation of glucose-6-phosphate dehydrogenase deficiency tests.

PubMed

Kahn, Maria; LaRue, Nicole; Bansil, Pooja; Kalnoky, Michael; McGray, Sarah; Domingo, Gonzalo J

2013-08-20

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common human enzyme deficiency. It is characterized by abnormally low levels of G6PD activity. Individuals with G6PD deficiency are at risk of undergoing acute haemolysis when exposed to 8‒aminoquinoline-based drugs, such as primaquine. For this reason it is imperative to identify individuals with G6PD deficiency prior to administering these anti-malarial drugs. There is a need for the development and evaluation of point-of-care G6PD deficiency screening tests suitable for areas of the developing world where malarial treatments are frequently administered. The development and evaluation of new G6PD tests will be greatly assisted with the availability of specimen repositories. Cryopreservation of erythrocytes was evaluated as a means to preserve G6PD activity. Blood specimens from 31 patients including ten specimens with normal G6PD activity, three with intermediate activity, and 18 with deficient activity were cryopreserved for up to six months. Good correlation in G6PD activity between fresh and cryopreserved specimens (R2 = 0.95). The cryopreserved specimens show an overall small drop in mean G6PD activity of 0.23 U/g Hb (P=0.23). Cytochemical staining showed that intracellular G6PD activity distribution within the red blood cell populations is preserved during cryopreservation. Furthermore, the mosaic composition of red blood cells in heterozygous women is also preserved for six months or more. The fluorescent spot and the BinaxNOW qualitative tests for G6PD deficiency also showed high concordance in G6PD status determination between cryopreserved specimens and fresh specimens. A methodology for establishing a specimen panel for evaluation of G6PD tests is described. The approach is similar to that used in several malaria research facilities for the cryopreservation of parasites in clinical specimens and axenic cultures. Specimens stored in this manner will aid both the development and evaluation of current and emerging G6PD tests. The availability of G6PD tests is a critical bottleneck to broader access to drugs that confer radical cure of Plasmodium vivax, a requirement for elimination of malaria.

Operational strategies of anti-malarial drug campaigns for malaria elimination in Zambia's southern province: a simulation study.

PubMed

Stuckey, Erin M; Miller, John M; Littrell, Megan; Chitnis, Nakul; Steketee, Rick

2016-03-09

Malaria elimination requires reducing both the potential of mosquitoes to transmit parasites to humans and humans to transmit parasites to mosquitoes. To achieve this goal in Southern province, Zambia a mass test and treat (MTAT) campaign was conducted from 2011-2013 to complement high coverage of long-lasting insecticide-treated nets (LLIN). To identify factors likely to increase campaign effectiveness, a modelling approach was applied to investigate the simulated effect of alternative operational strategies for parasite clearance in southern province. OpenMalaria, a discrete-time, individual-based stochastic model of malaria, was parameterized for the study area to simulate anti-malarial drug administration for interruption of transmission. Simulations were run for scenarios with a range of artemisinin-combination therapies, proportion of the population reached by the campaign, targeted age groups, time between campaign rounds, Plasmodium falciparum test protocols, and the addition of drugs aimed at preventing onward transmission. A sensitivity analysis was conducted to assess uncertainty of simulation results. Scenarios were evaluated based on the reduction in all-age parasite prevalence during the peak transmission month one year following the campaign, compared to the currently-implemented strategy of MTAT 19 % population coverage at pilot and 40 % coverage during the first year of implementation in the presence of 56 % LLIN use and 18 % indoor residual spray coverage. Simulation results suggest the most important determinant of success in reducing prevalence is the population coverage achieved in the campaign, which would require more than 1 year of campaign implementation for elimination. The inclusion of single low-dose primaquine, which acts as a gametocytocide, or ivermectin, which acts as an endectocide, to the drug regimen did not further reduce parasite prevalence one year following the campaign compared to the currently-implemented strategy. Simulation results indicate a high proportion of low-density infections were missed by rapid diagnostic tests that would be treated and cleared with mass drug administration (MDA). The optimal implementation strategy for MTAT or MDA will vary by background level of prevalence, by rate of infections imported to the area, and by ability to operationally achieve high population coverage. Overall success with new parasite clearance strategies depends on continued coverage of vector control interventions to ensure sustained gains in reduction of disease burden.

Health systems readiness and management of febrile outpatients under low malaria transmission in Vanuatu.

PubMed

Zurovac, Dejan; Guintran, Jean-Olivier; Donald, Wesley; Naket, Esau; Malinga, Josephine; Taleo, George

2015-12-02

Vanuatu, an archipelago country in Western Pacific harbouring low Plasmodium falciparum and Plasmodium vivax malaria transmission, has been implementing a malaria case management policy, recommending parasitological testing of patients with fever and anti-malarial treatment for test-positive only patients. A health facility survey to evaluate the health systems readiness to implement the policy and the quality of outpatient management for patients with fever was undertaken. A cross-sectional, cluster sample survey, using a range of quality-of-care methods, included all health centres and hospitals in Vanuatu. The main outcome measures were coverage of health facilities and health workers with commodities and support interventions, adherence to test and treatment recommendations, and factors influencing malaria testing. The survey was undertaken in 2014 during the low malaria season and included 41 health facilities, 67 health workers and 226 outpatient consultations for patients with fever. All facilities had capacity for parasitological diagnosis, 95.1 % stocked artemether-lumefantrine and 63.6 % primaquine. The coverage of health workers with support interventions ranged from 50 to 70 %. Health workers' knowledge was high only regarding treatment policy for uncomplicated P. falciparum malaria (83.4 %). History taking and clinical examination practices were sub-optimal. Some 35.0 % (95 % CI 23.4-48.6) of patients with fever were tested for malaria, of which all results were negative and only one patient received anti-malarial treatment. Testing was significantly higher for patients age 5 years and older (OR = 2.33; 95 % CI 1.48-5.02), seen by less qualified health workers (OR = 2.73; 95 % CI 1.48-5.02), health workers who received malaria case management training (OR = 2.39; 95 % CI 1.28-4.47) and patients with increased temperature (OR = 2.56; 95 % CI 1.17-5.57), main complaint of fever (OR = 5.82; 95 % CI 1.26-26.87) and without runny nose (OR = 3.75; 95 % CI 1.36-10.34). Antibiotic use was very high (77.4 %) with sub-optimal dispensing and counselling practices. Health facility and health worker readiness to implement policy is higher for falciparum than vivax malaria. Clinical and malaria testing practices are sub-optimal, however adherence to test negative results is nearly universal. Use of antibiotics is irrational. Quantitative and qualitative improvements of ongoing interventions are needed to re-inforce clinical practices in this area characterized by difficult access, human resource shortages but aspiring towards malaria elimination.

Heterogeneity of G6PD deficiency prevalence in Mozambique: a school-based cross-sectional survey in three different regions.

PubMed

Galatas, Beatriz; Mabote, Lurdes; Simone, Wilson; Matambisso, Gloria; Nhamussua, Lidia; Mañú-Pereira, María Del Mar; Menéndez, Clara; Saute, Francisco; Macete, Eusebio; Bassat, Quique; Alonso, Pedro; Aide, Pedro

2017-01-19

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hereditary enzymatic abnormality that affects more than 400 million people worldwide. Most deficient individuals do not manifest any symptoms; however, several precipitant agents-such as fava intake, infections, or several drugs-may trigger acute haemolytic anaemia. Countries should be informed of the prevalence of this enzymatic anomaly within their borders, in order to make safe and appropriate national decisions regarding the use of potentially unsafe drugs for G6PD deficient individuals. A school-based cross-sectional survey was conducted in three districts in Mozambique, namely Manhiça, located in the south; Mocuba in the centre; and Pemba in the northern tip of the country. G6PD deficiency was evaluated using the CareStart™ diagnostic test, and enzyme activity levels were measured through fluorescence spectrophotometry in deficient individuals. Chi squared and ANOVA tests were used to assess prevalence and mean enzyme activity differences, and logistic regression was used to identify risk factors associated to the deficiency. G6PD deficiency prevalence estimates were lowest in the northern city of Pemba (8.3%) and among Emakhuwas and Shimakondes, and higher in the centre and southern regions of the country (16.8 and 14.6%, respectively), particularly among Elomwes and Xichanganas. G6PD deficiency was significantly more prevalent among male students than females (OR = 1.4, 95% CI 1.0-1.8, p = 0.02), although enzyme activity levels were not different among deficient individuals from either gender group. Finally, median deficiency levels were found to be more severe among the deficient students from the north (0.7 U/gHg [0.2-0.7] p < 0.001) and south (0.7 U/gHg [0.5-2.5]), compared to those from the centre (1.4 U/gHg [0.6-2.1]). These findings suggest that Mozambique, as a historically high malaria-endemic country has considerable levels of G6PD deficiency, that vary significantly across the country. This should be considered when planning national strategies for the use of licensed drugs that may be associated to haemolysis among G6PD individuals, or prior to the performance of future trials using primaquine and other 8-aminoquinolines derivatives. Registration Number CISM local ethics committee (CIBS-25/013, 4th of December 2013), and the National Ethics Committee of Mozambique (IRB00002657, 28th of February 2014).

The chemotherapy of rodent malaria. LXI. Drug combinations to impede the selection of drug resistance, part 4: the potential role of 8-aminoquinolines.

PubMed

Peters, W; Stewart, L B; Robinson, B L

2003-04-01

The influence of combinations containing the blood schizontocides chloroquine (CQ) or mefloquine (MEF), together with the 8-aminoquinolines (8AQ) primaquine (PQ) or the new, long-acting compound, tafenoquine (TAF), on the rate of selection of resistance to the individual compounds was examined using the asexual, intra-erythrocytic stages in rodent malaria models. The two main procedures used were a 'serial technique' (ST) and the '2%- relapse technique' (2%RT). The ST provided evidence for the contention that a combination with PQ slowed the selection of resistance to CQ or MEF; it has been shown previously that synergism exists between CQ and either PQ or TAF in rodent malaria. Data obtained with the 2%RT, and three parasite lines derived from Plasmodium berghei N (the 238B line), P. chabaudi ASS (the 238C line) or P. yoelii ssp. NS (the 238Y line), indicated that resistance to TAF used alone is acquired rapidly under drug pressure and that this resistance is stable when selection pressure is removed. In the 2%RT, resistance to CQ developed when another line of P. chabaudi (AS15) was exposed to that compound alone, although more slowly than the development of resistance to TAF in the 238C line. However, treatment of a TC line of P. chabaudi, developed in a 2%RT using a combination of CQ with TAF, led to little resistance to either compound. A totally unforeseen phenomenon was the appearance of a high level of resistance to CQ in the 238C line of P. chabaudi that had been exposed only to TAF; this was not observed with the 238B or 238Y lines. Attention has been refocused recently on the use of 8AQ for prophylaxis in man. It remains to be determined if resistance in the asexual intra-erythrocytic forms is carried over to the other stages of the malarial life-cycle, especially the hepatic, pre-erythrocytic schizonts. The implications of the present results for the possible clinical deployment of 8AQ in the future are discussed. It is concluded that, whereas use of an 8AQ alone carries a high risk of selecting resistance, combinations containing 8AQ may have a place in the protection of blood schizontocides that are to be deployed in endemic areas. Furthermore, the inherent gametocytocidal action of the 8AQ should promote the reduction of transmission.

[The risk of malaria during travel, observations in the department of infectious diseases in Cracow from 1996 to 2010].

PubMed

Kalinowska-Nowak, Anna; Bociaga-Jasik, Monika; Leśniak, Maciej; Mach, Tomasz; Garlicki, Aleksander

2012-01-01

Actually in Poland malaria is not present as an endemic disease, but is one of the most common "imported" diseases. In its mild form it is an awkward illness with recurring fever, whereas the more severe form, which is caused by Plasmodium falciparum can be life-threatening. Epidemiological and clinical analysis on malaria-infected patients hospitalized in the Department of Infectious Diseases in Cracow from 1996 to 2010. Interview, physical examination, laboratory tests and usg of the abdomen were performed among all patients. Diagnosis was performed by malaria parasites detection in direct microscopic observation of thick and thin blood films. Patients were treated with antimalarial drugs according to parasites species and previously used prophylaxis. 33 people with malaria, 26 men (79%) and 7 women (21%), aged 24-71 years were hospitalized. Annually 1 to 4 patients were treated, but in year 2008 - 7 patients. 18 persons (54%) were travelling as a tourists to the endemic regions, including 15 persons on short trips (up to 1 month). 15 persons (46%) were involved in business-trips and missions with over 2 years stay. Most patients visited Africa (25 persons), 4 travelled to Oceania, 3 to Asia and 1 to South America. Only 3 patients (9%) used recommended antimalarial prophylaxis. Symptoms of malaria usually appeared a few days after returning to Poland, 1 woman presented the symptoms after 1 year, 4 patients were presenting the symptoms already in the tropics. 25 persons (76%) had malaria for the first time. Clinical symptoms among patients were: fever preceded by shivering (100%), sweating (94%), muscles and joints pain (84%), nausea and vomiting (24%), diarrhoea (12%), jaundice (12%), cough (6%), coma (6%), multiorgan failure (6%). 12 persons were diagnosed with hepatomegaly, 21 with splenomegaly, 9 with hemolytic anaemia, 18 with thrombocytopenia and 14 with elevation of liver enzymes. P. falciparum infection was proven in 15 patients (46%), P. vivax in 11 patients (33%), P. ovale in 1 patient (3%), mixed infection (P. falciparum and P. ovale) in 6 patients (18%). In the treatment of P. falciparum infection quinine with doxycycline (18 patients) or mefloquine (2 patients) were used, in other cases chloroquine with following primaquine. 32 patients recovered, 1 patient with cerebral malaria died. Malaria was most commonly diagnosed among tourists staying for short period of time in an endemic area. Travelers did not use accurate antimalarial prophylaxis. Malaria must be excluded as a potential diagnosis among all fever suffering persons returning from the tropics.

Prevalence and patterns of antifolate and chloroquine drug resistance markers in Plasmodium vivax across Pakistan

PubMed Central

2013-01-01

Background Plasmodium vivax is the most prevalent malaria species in Pakistan, with a distribution that coincides with Plasmodium falciparum in many parts of the country. Both species are likely exposed to drug pressure from a number of anti-malarials including chloroquine, sulphadoxine-pyrimethamine (SP), and artemisinin combination therapy, yet little is known regarding the effects of drug pressure on parasite genes associated with drug resistance. The aims of this study were to determine the prevalence of polymorphisms in the SP resistance-associated genes pvdhfr, pvdhps and chloroquine resistance-associated gene pvmdr1 in P. vivax isolates collected from across the country. Methods In 2011, 801 microscopically confirmed malaria-parasite positive filter paper blood samples were collected at 14 sites representing four provinces and the capital city of Islamabad. Species-specific polymerase chain reaction (PCR) was used to identify human Plasmodium species infection. PCR-positive P. vivax isolates were subjected to sequencing of pvdhfr, pvdhps and pvmdr1 and to real-time PCR analysis to assess pvmdr1 copy number variation. Results Of the 801 samples, 536 were determined to be P. vivax, 128 were P. falciparum, 43 were mixed vivax/falciparum infections and 94 were PCR-negative for Plasmodium infection. Of PCR-positive P. vivax samples, 372 were selected for sequence analysis. Seventy-six of the isolates (23%) were double mutant at positions S58R and S117N in pvdhfr. Additionally, two mutations at positions N50I and S93H were observed in 55 (15%) and 24 (7%) of samples, respectively. Three 18 base pair insertion-deletions (indels) were observed in pvdhfr, with two insertions at different nucleotide positions in 36 isolates and deletions in 10. Ninety-two percent of samples contained the pvdhps (S382/A383G/K512/A553/V585) SAKAV wild type haplotype. For pvmdr1, all isolates were wild type at position Y976F and 335 (98%) carried the mutation at codon F1076L. All isolates harboured single copies of the pvmdr1 gene. Conclusions The prevalence of mutations associated with SP resistance in P. vivax is low in Pakistan. The high prevalence of P. vivax mutant pvmdr1 codon F1076L indicates that efficacy of chloroquine plus primaquine could be in danger of being compromised, but further studies are required to assess the clinical relevance of this observation. These findings will serve as a baseline for further monitoring of drug-resistant P. vivax malaria in Pakistan. PMID:24007534

Prevalence and Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency at the China-Myanmar Border.

PubMed

Li, Qing; Yang, Fang; Liu, Rong; Luo, Lan; Yang, Yuling; Zhang, Lu; Liu, Huaie; Zhang, Wen; Fan, Zhixiang; Yang, Zhaoqing; Cui, Liwang; He, Yongshu

2015-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hereditary disease that predisposes red blood cells to oxidative damage. G6PD deficiency is particularly prevalent in historically malaria-endemic areas. Use of primaquine for malaria treatment may result in severe hemolysis in G6PD deficient patients. In this study, we systematically evaluated the prevalence of G6PD deficiency in the Kachin (Jingpo) ethnic group along the China-Myanmar border and determined the underlying G6PD genotypes. We surveyed G6PD deficiency in 1770 adult individuals (671 males and 1099 females) of the Kachin ethnicity using a G6PD fluorescent spot test. The overall prevalence of G6PD deficiency in the study population was 29.6% (523/1770), among which 27.9% and 30.6% were males and females, respectively. From these G6PD deficient samples, 198 unrelated individuals (147 females and 51 males) were selected for genotyping at 11 known G6PD single nucleotide polymorphisms (SNPs) in Southeast Asia (ten in exons and one in intron 11) using a multiplex SNaPshot assay. Mutations with known association to a deficient phenotype were detected in 43.9% (87/198) of cases, intronic and synonymous mutations were detected alone in 34.8% (69/198) cases and no mutation were found in 21.2% (42/198) cases. Five non-synonymous mutations, Mahidol 487G>A, Kaiping 1388G>A, Canton 1376G>T, Chinese 4 392G>T, and Viangchan 871G>A were detected. Of the 87 cases with known deficient mutations, the Mahidol variant was the most common (89.7%; 78/87), followed by the Kaiping (8.0%; 7/87) and the Viangchan (2.2%; 2/87) variants. The Canton and Chinese 4 variants were found in 1.1% of these 87 cases. Among them, two females carried the Mahidol/Viangchan and Mahidol/Kaiping double mutations, respectively. Interestingly, the silent SNPs 1311C>T and IVS11nt93T>C both occurred in the same 95 subjects with frequencies at 56.4% and 23.5% in tested females and males, respectively (P<0.05). It is noteworthy that 24 subjects carrying the Mahidol mutation and two carrying the Kaiping mutation also carried the 1311C>T/IVS11nt93T>C SNPs. Further studies are needed to determine the enzyme levels of the G6PD deficient people and presence of additional G6PD mutations in the study population.

Prevalence and molecular characterization of G6PD deficiency in two Plasmodium vivax endemic areas in Venezuela: predominance of the African A-(202A/376G) variant.

PubMed

Vizzi, Esmeralda; Bastidas, Gilberto; Hidalgo, Mariana; Colman, Laura; Pérez, Hilda A

2016-01-11

Glucose-6-phosphate dehydrogenase (G6PD) deficiency causes acute haemolytic anaemia triggered by oxidative drugs such as primaquine (PQ), used for Plasmodium vivax malaria radical cure. However, in many endemic areas of vivax malaria, patients are treated with PQ without any evaluation of their G6PD status. G6PD deficiency and its genetic heterogeneity were evaluated in northeastern and southeastern areas from Venezuela, Cajigal (Sucre state) and Sifontes (Bolívar state) municipalities, respectively. Blood samples from 664 randomly recruited unrelated individuals were screened for G6PD activity by a quantitative method. Mutation analysis for exons 4-8 of G6PD gen was performed on DNA isolated from G6PD-deficient (G6PDd) subjects through PCR-RFLP and direct DNA sequencing. Quantitative biochemical characterization revealed that overall 24 (3.6%) subjects were G6PDd (average G6PD enzyme activity 4.5 ± 1.2 U/g Hb, moderately deficient, class III), while DNA analysis showed one or two mutated alleles in 19 of them (79.2%). The G6PD A-(202A/376G) variant was the only detected in 17 (70.8%) individuals, 13 of them hemizygous males and four heterozygous females. Two males carried only the 376A → G mutation. No other mutation was found in the analysed exons. The G6PDd prevalence was as low as that one shown by nearby countries. This study contributes to the knowledge of the genetic background of Venezuelan population, especially of those living in malaria-endemic areas. Despite the high degree of genetic mixing described for Venezuelan population, a net predominance of the mild African G6PD A-(202A/376G) variant was observed among G6PDd subjects, suggesting a significant flow of G6PD genes from Africa to Americas, almost certainly introduced through African and/or Spanish immigrants during and after the colonization. The data suggest that 1:27 individuals of the studied population could be G6PDd and therefore at risk of haemolysis under precipitating factors. Information about PQ effect on G6PDd individuals carrying mild variant is limited, but since the regimen of 45 mg weekly dose for prevention of malaria relapse does not seem to be causing clinically significant haemolysis in people having the G6PD A-variant, a reasoned weighing of risk-benefit for its use in Venezuela should be done, when implementing public health strategies of control and elimination.

Co-inheritance of glucose-6-phosphate dehydrogenase deficiency mutations and hemoglobin E in a Kachin population in a malaria-endemic region of Southeast Asia

PubMed Central

He, Lijun; Li, Qing; Wu, Yanrui; Luo, Lan; Li, Hong; Ma, Limei; Yang, Zhaoqing; He, Yongshu; Cui, Liwang

2017-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency and hemoglobin E (HbE, β26 Glu-Lys) are two common red cell disorders in Southeast Asia. G6PD deficiency produces hemolytic anemia, which can be triggered by certain drugs or infections. HbE is asymptomatic or is manifested as microcytic, minimally hemolytic anemia. The association between G6PD deficiency and HbE is little understood. This study aimed to investigate G6PD deficiency and HbE in a Kachin ethnic group in the China-Myanmar border area. G6PD enzyme activity was measured using a quantitative G6PD assay, G6PD variants genotyped by the SNaPshot assay, and an HbE gene mutation identified by an amplification refractory mutation system and subsequently confirmed by using a reverse dot blot hybridization assay from 100 unrelated individuals in the study area. G6PD enzyme activity ranged from 0.4 to 24.7 U/g Hb, and six males had severe G6PD deficiency (<0.12–1.2 U/g Hb), while six males and 12 females had mild G6PD deficiency (>1.2–4.5 U/g Hb). Among the 24 G6PD-deficient subjects, 22 (92%) had the Mahidol 487G>A mutation (12 male hemizygotes, one female homozygote, and nine female heterozygotes), while the G6PD genotypes in two female subjects were unknown. HbE was identified in 39 subjects (20 males and 19 females), including 15 HbEE (seven males and eight females) and 24 HbAE (13 males and 11 females). Twenty-three subjects co-inherited both G6PD deficiency and HbE (22 with HbAE and one with HbEE). Whereas mean Hb levels were not significantly different between the HbA and HbE groups, G6PD-deficient males had significantly lower Hb levels than G6PD-normal males (P < 0.05, t-test). However, it is noteworthy that two G6PD-deficient hemizygous males with HbAE were severely anemic with Hb levels below 50 g/L. This study revealed high prevalence of co-inheritance of G6PD deficiency with HbAE in the Kachin ethnicity, and a potential interaction of the G6PD Mahidol 487G>A and HbAE in males leading to severe anemia. The presence of 6% males with severe G6PD deficiency raised a major concern in the use of primaquine for radical cure of vivax malaria. PMID:28531196

Co-inheritance of glucose-6-phosphate dehydrogenase deficiency mutations and hemoglobin E in a Kachin population in a malaria-endemic region of Southeast Asia.

PubMed

Deng, Zeshuai; Yang, Fang; Bai, Yao; He, Lijun; Li, Qing; Wu, Yanrui; Luo, Lan; Li, Hong; Ma, Limei; Yang, Zhaoqing; He, Yongshu; Cui, Liwang

2017-01-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency and hemoglobin E (HbE, β26 Glu-Lys) are two common red cell disorders in Southeast Asia. G6PD deficiency produces hemolytic anemia, which can be triggered by certain drugs or infections. HbE is asymptomatic or is manifested as microcytic, minimally hemolytic anemia. The association between G6PD deficiency and HbE is little understood. This study aimed to investigate G6PD deficiency and HbE in a Kachin ethnic group in the China-Myanmar border area. G6PD enzyme activity was measured using a quantitative G6PD assay, G6PD variants genotyped by the SNaPshot assay, and an HbE gene mutation identified by an amplification refractory mutation system and subsequently confirmed by using a reverse dot blot hybridization assay from 100 unrelated individuals in the study area. G6PD enzyme activity ranged from 0.4 to 24.7 U/g Hb, and six males had severe G6PD deficiency (<0.12-1.2 U/g Hb), while six males and 12 females had mild G6PD deficiency (>1.2-4.5 U/g Hb). Among the 24 G6PD-deficient subjects, 22 (92%) had the Mahidol 487G>A mutation (12 male hemizygotes, one female homozygote, and nine female heterozygotes), while the G6PD genotypes in two female subjects were unknown. HbE was identified in 39 subjects (20 males and 19 females), including 15 HbEE (seven males and eight females) and 24 HbAE (13 males and 11 females). Twenty-three subjects co-inherited both G6PD deficiency and HbE (22 with HbAE and one with HbEE). Whereas mean Hb levels were not significantly different between the HbA and HbE groups, G6PD-deficient males had significantly lower Hb levels than G6PD-normal males (P < 0.05, t-test). However, it is noteworthy that two G6PD-deficient hemizygous males with HbAE were severely anemic with Hb levels below 50 g/L. This study revealed high prevalence of co-inheritance of G6PD deficiency with HbAE in the Kachin ethnicity, and a potential interaction of the G6PD Mahidol 487G>A and HbAE in males leading to severe anemia. The presence of 6% males with severe G6PD deficiency raised a major concern in the use of primaquine for radical cure of vivax malaria.

Tafenoquine treatment of Plasmodium vivax malaria: suggestive evidence that CYP2D6 reduced metabolism is not associated with relapse in the Phase 2b DETECTIVE trial.

PubMed

St Jean, Pamela L; Xue, Zhengyu; Carter, Nick; Koh, Gavin C K W; Duparc, Stephan; Taylor, Maxine; Beaumont, Claire; Llanos-Cuentas, Alejandro; Rueangweerayut, Ronnatrai; Krudsood, Srivicha; Green, Justin A; Rubio, Justin P

2016-02-18

Tafenoquine (TQ) and primaquine (PQ) are 8-aminoquinolines (8-AQ) with anti-hypnozoite activity against vivax malaria. PQ is the only FDA-approved medicine for preventing relapsing Plasmodium vivax infection and TQ is currently in phase 3 clinical trials for the same indication. Recent studies have provided evidence that cytochrome P450 (CYP) metabolism via CYP2D6 plays a role in PQ efficacy against P. vivax and have suggested that this effect may extend to other 8-AQs, including TQ. Here, a retrospective pharmacogenetic (PGx) investigation was performed to assess the impact of CYP2D6 metabolism on TQ and PQ efficacy in the treatment of P. vivax in the DETECTIVE study (TAF112582), a recently completed, randomized, phase 2b dose-ranging clinical trial. The impact of CYP2D6 on TQ pharmacokinetics (PK) was also investigated in TAF112582 TQ-treated subjects and in vitro CYP metabolism of TQ was explored. A limitation of the current study is that TAF112582 was not designed to be well powered for PGx, thus our findings are based on TQ or PQ efficacy in CYP2D6 intermediate metabolizers (IM), as there were insufficient poor metabolizers (PM) to draw any conclusion on the impact of the PM phenotype on efficacy. The impact of genetically-predicted CYP2D6 reduced metabolism on relapse-free efficacy six months post-dosing of TQ or PQ, both administered in conjunction with chloroquine (CQ), was assessed using exact statistical methods in 198 P. vivax-infected study participants comparing IM to extensive metabolizers (EM). The influence of CYP2D6 metabolizer phenotypes on TQ PK was assessed comparing median TQ area under the curve (AUC). In vitro metabolism of TQ was investigated using recombinant, over-expressed human CYP enzymes and human hepatocytes. Metabolite identification experiments were performed using liquid chromatography-mass spectrometry. Reduction of CYP2D6 activity was not associated with an increase in relapse-rate in TQ-treated subjects (p = 0.57). In contrast, and in accordance with recent literature, CYP2D6 IMs were more common (p = 0.05) in PQ-treated subjects who relapsed (50 %) than in subjects who remained relapse-free (17 %). Further, CYP2D6 metabolizer phenotypes had no significant effect on TQ AUC, and only minimal metabolism of TQ could be detected in hepatic in vitro systems. Together, these data provide preliminary evidence that in CYP2D6 IMs, TQ efficacy in P. vivax-infected individuals is not diminished to the same extent as PQ. As there were no PMs in either the TQ or PQ treatment arms of TAF112582, no conclusions could be drawn on potential differences in PMs. These findings suggest that differential effects of CYP2D6 metabolism on TQ and PQ efficacy could be a differentiation factor between these 8-AQs, but results remain to be confirmed prospectively in the ongoing phase 3 studies.

Strategies for understanding and reducing the Plasmodium vivax and Plasmodium ovale hypnozoite reservoir in Papua New Guinean children: a randomised placebo-controlled trial and mathematical model.

PubMed

Robinson, Leanne J; Wampfler, Rahel; Betuela, Inoni; Karl, Stephan; White, Michael T; Li Wai Suen, Connie S N; Hofmann, Natalie E; Kinboro, Benson; Waltmann, Andreea; Brewster, Jessica; Lorry, Lina; Tarongka, Nandao; Samol, Lornah; Silkey, Mariabeth; Bassat, Quique; Siba, Peter M; Schofield, Louis; Felger, Ingrid; Mueller, Ivo

2015-10-01

The undetectable hypnozoite reservoir for relapsing Plasmodium vivax and P. ovale malarias presents a major challenge for malaria control and elimination in endemic countries. This study aims to directly determine the contribution of relapses to the burden of P. vivax and P. ovale infection, illness, and transmission in Papua New Guinean children. From 17 August 2009 to 20 May 2010, 524 children aged 5-10 y from East Sepik Province in Papua New Guinea (PNG) participated in a randomised double-blind placebo-controlled trial of blood- plus liver-stage drugs (chloroquine [CQ], 3 d; artemether-lumefantrine [AL], 3 d; and primaquine [PQ], 20 d, 10 mg/kg total dose) (261 children) or blood-stage drugs only (CQ, 3 d; AL, 3 d; and placebo [PL], 20 d) (263 children). Participants, study staff, and investigators were blinded to the treatment allocation. Twenty children were excluded during the treatment phase (PQ arm: 14, PL arm: 6), and 504 were followed actively for 9 mo. During the follow-up time, 18 children (PQ arm: 7, PL arm: 11) were lost to follow-up. Main primary and secondary outcome measures were time to first P. vivax infection (by qPCR), time to first clinical episode, force of infection, gametocyte positivity, and time to first P. ovale infection (by PCR). A basic stochastic transmission model was developed to estimate the potential effect of mass drug administration (MDA) for the prevention of recurrent P. vivax infections. Targeting hypnozoites through PQ treatment reduced the risk of having at least one qPCR-detectable P. vivax or P. ovale infection during 8 mo of follow-up (P. vivax: PQ arm 0.63/y versus PL arm 2.62/y, HR = 0.18 [95% CI 0.14, 0.25], p < 0.001; P. ovale: 0.06 versus 0.14, HR = 0.31 [95% CI 0.13, 0.77], p = 0.011) and the risk of having at least one clinical P. vivax episode (HR = 0.25 [95% CI 0.11, 0.61], p = 0.002). PQ also reduced the molecular force of P. vivax blood-stage infection in the first 3 mo of follow-up (PQ arm 1.90/y versus PL arm 7.75/y, incidence rate ratio [IRR] = 0.21 [95% CI 0.15, 0.28], p < 0.001). Children who received PQ were less likely to carry P. vivax gametocytes (IRR = 0.27 [95% CI 0.19, 0.38], p < 0.001). PQ had a comparable effect irrespective of the presence of P. vivax blood-stage infection at the time of treatment (p = 0.14). Modelling revealed that mass screening and treatment with highly sensitive quantitative real-time PCR, or MDA with blood-stage treatment alone, would have only a transient effect on P. vivax transmission levels, while MDA that includes liver-stage treatment is predicted to be a highly effective strategy for P. vivax elimination. The inclusion of a directly observed 20-d treatment regime maximises the efficiency of hypnozoite clearance but limits the generalisability of results to real-world MDA programmes. These results suggest that relapses cause approximately four of every five P. vivax infections and at least three of every five P. ovale infections in PNG children and are important in sustaining transmission. MDA campaigns combining blood- and liver-stage treatment are predicted to be a highly efficacious intervention for reducing P. vivax and P. ovale transmission. ClinicalTrials.gov NCT02143934.

Mass drug administration for malaria

PubMed Central

Poirot, Eugenie; Skarbinski, Jacek; Sinclair, David; Kachur, S Patrick; Slutsker, Laurence; Hwang, Jimee

2013-01-01

Background Mass drug administration (MDA), defined as the empiric administration of a therapeutic antimalarial regimen to an entire population at the same time, has been a historic component of many malaria control and elimination programmes, but is not currently recommended. With renewed interest in MDA and its role in malaria elimination, this review aims to summarize the findings from existing research studies and program experiences of MDA strategies for reducing malaria burden and transmission. Objectives To assess the impact of antimalarial MDA on population asexual parasitaemia prevalence, parasitaemia incidence, gametocytaemia prevalence, anaemia prevalence, mortality and MDA-associated adverse events. Search methods We searched the Cochrane Infectious Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE+, EMBASE, to February 2013. We also searched CABS Abstracts, LILACS, reference lists, and recent conference proceedings. Selection criteria Cluster-randomized trials and non-randomized controlled studies comparing therapeutic MDA versus placebo or no MDA, and uncontrolled before-and-after studies comparing post-MDA to baseline data were selected. Studies administering intermittent preventive treatment (IPT) to sub-populations (for example, pregnant women, children or infants) were excluded. Data collection and analysis Two authors independently reviewed studies for inclusion, extracted data and assessed risk of bias. Studies were stratified by study design and then subgrouped by endemicity, by co-administration of 8-aminoquinoline plus schizonticide drugs and by plasmodium species. The quality of evidence was assessed using the GRADE approach. Main results Two cluster-randomized trials, eight non-randomized controlled studies and 22 uncontrolled before-and-after studies are included in this review. Twenty-two studies (29 comparisons) compared MDA to placebo or no intervention of which two comparisons were conducted in areas of low endemicity (≤5%), 12 in areas of moderate endemicity (6-39%) and 15 in areas of high endemicity (≥ 40%). Ten studies evaluated MDA plus other vector control measures. The studies used a wide variety of MDA regimens incorporating different drugs, dosages, timings and numbers of MDA rounds. Many of the studies are now more than 30 years old. Areas of low endemicity (≤5%) Within the first month post-MDA, a single uncontrolled before-and-after study conducted in 1955 on a small Taiwanese island reported a much lower prevalence of parasitaemia following a single course of chloroquine compared to baseline (1 study, very low quality evidence). This lower parasite prevalence was still present after more than 12 months (one study, very low quality evidence). In addition, one cluster-randomized trial evaluating MDA in a low endemic setting reported zero episodes of parasitaemia at baseline, and throughout five months of follow-up in both the control and intervention arms (one study, very low quality evidence). Areas of moderate endemicity (6-39%) Within the first month post-MDA, the prevalence of parasitaemia was much lower in three non-randomized controlled studies from Kenya and India in the 1950s (RR 0.03, 95% CI 0.01 to 0.08, three studies, moderate quality evidence), and in three uncontrolled before-and-after studies conducted between 1954 and 1961 (RR 0.29, 95% CI 0.17 to 0.48, three studies,low quality evidence). The longest follow-up in these settings was four to six months. At this time point, the prevalence of parasitaemia remained substantially lower than controls in the two non-randomized controlled studies (RR 0.18, 95% CI 0.10 to 0.33, two studies, low quality evidence). In contrast, the two uncontrolled before-and-after studies found mixed results: one found no difference and one found a substantially higher prevalence compared to baseline (not pooled, two studies, very low quality evidence). Areas of high endemicity (≥40%) Within the first month post-MDA, the single cluster-randomized trial from the Gambia in 1999 found no significant difference in parasite prevalence (one study, low quality evidence). However, prevalence was much lower during the MDA programmes in three non-randomized controlled studies conducted in the 1960s and 1970s (RR 0.17, 95% CI 0.11 to 0.27, three studies, moderate quality evidence), and within one month of MDA in four uncontrolled before-and-after studies (RR 0.37, 95% CI 0.28 to 0.49, four studies,low quality evidence). Four trials reported changes in prevalence beyond three months. In the Gambia, the single cluster-randomized trial found no difference at five months (one trial, moderate quality evidence). The three uncontrolled before-and-after studies had mixed findings with large studies from Palestine and Cambodia showing sustained reductions at four months and 12 months, respectively, and a small study from Malaysia showing no difference after four to six months of follow-up (three studies,low quality evidence). 8-aminoquinolines We found no studies directly comparing MDA regimens that included 8-aminoquinolines with regimens that did not. In a crude subgroup analysis with a limited number of studies, we were unable to detect any evidence of additional benefit of primaquine in moderate- and high-transmission settings. Plasmodium species In studies that reported species-specific outcomes, the same interventions resulted in a larger impact on Plasmodium falciparum compared to P. vivax. Authors' conclusions MDA appears to reduce substantially the initial risk of malaria parasitaemia. However, few studies showed sustained impact beyond six months post-MDA, and those that did were conducted on small islands or in highland settings. To assess whether there is an impact of MDA on malaria transmission in the longer term requires more quasi experimental studies with the intention of elimination, especially in low- and moderate-transmission settings. These studies need to address any long-term outcomes, any potential barriers for community uptake, and contribution to the development of drug resistance. PLAIN LANGUAGE SUMMARY Administration of antimalarial drugs to whole populations Malaria is the most important mosquito-borne disease caused by a parasite, accounting for an estimated 660,000 deaths annually. Fortunately, malaria is both preventable and treatable. Several malaria control tools currently exist, and new and innovative approaches are continually under development. The administration of drugs against malaria to whole populations, termed mass drug administration (MDA), was a component of many malaria elimination programmes in the 1950s, and is once again attracting interest as a malaria elimination tool. As a consequence, it is important to review the currently available literature in order to assess the potential for this strategy to reduce malaria burden and transmission, and to identify gaps in our understanding. This review assessed the impact of MDA on several malaria-specific outcome measures. Thirty-two studies were included in this review, from sites in Asia, Africa, Europe and the Americas. The review found that although MDA can reduce the initial risk of malaria-specific outcomes, these reductions are often not sustained. However, a few studies conducted on small islands or in highland areas did show sustained impact more than six months after MDA. Adverse events were inadequately addressed in most studies. Notable severe drug reactions, including haemolysis, haemoglobinuria, severe anaemia and death, were reported with 8-aminoquinoline plus schizonticide drug co-administration, while severe skin reactions were reported with sulphadoxine-pyrimethamine plus artesunate plus primaquine. Assessing the true impact of MDA programmes can be a challenge due to the heterogeneity of the study methods employed. Nonetheless, this review can help guide future antimalarial MDA interventions and their evaluation. PMID:24318836

Strategies for Understanding and Reducing the Plasmodium vivax and Plasmodium ovale Hypnozoite Reservoir in Papua New Guinean Children: A Randomised Placebo-Controlled Trial and Mathematical Model

PubMed Central

Robinson, Leanne J.; Wampfler, Rahel; Betuela, Inoni; Karl, Stephan; White, Michael T.; Li Wai Suen, Connie S. N.; Hofmann, Natalie E.; Kinboro, Benson; Waltmann, Andreea; Brewster, Jessica; Lorry, Lina; Tarongka, Nandao; Samol, Lornah; Silkey, Mariabeth; Bassat, Quique; Siba, Peter M.; Schofield, Louis; Felger, Ingrid; Mueller, Ivo

2015-01-01

Background The undetectable hypnozoite reservoir for relapsing Plasmodium vivax and P. ovale malarias presents a major challenge for malaria control and elimination in endemic countries. This study aims to directly determine the contribution of relapses to the burden of P. vivax and P. ovale infection, illness, and transmission in Papua New Guinean children. Methods and Findings From 17 August 2009 to 20 May 2010, 524 children aged 5–10 y from East Sepik Province in Papua New Guinea (PNG) participated in a randomised double-blind placebo-controlled trial of blood- plus liver-stage drugs (chloroquine [CQ], 3 d; artemether-lumefantrine [AL], 3 d; and primaquine [PQ], 20 d, 10 mg/kg total dose) (261 children) or blood-stage drugs only (CQ, 3 d; AL, 3 d; and placebo [PL], 20 d) (263 children). Participants, study staff, and investigators were blinded to the treatment allocation. Twenty children were excluded during the treatment phase (PQ arm: 14, PL arm: 6), and 504 were followed actively for 9 mo. During the follow-up time, 18 children (PQ arm: 7, PL arm: 11) were lost to follow-up. Main primary and secondary outcome measures were time to first P. vivax infection (by qPCR), time to first clinical episode, force of infection, gametocyte positivity, and time to first P. ovale infection (by PCR). A basic stochastic transmission model was developed to estimate the potential effect of mass drug administration (MDA) for the prevention of recurrent P. vivax infections. Targeting hypnozoites through PQ treatment reduced the risk of having at least one qPCR-detectable P. vivax or P. ovale infection during 8 mo of follow-up (P. vivax: PQ arm 0.63/y versus PL arm 2.62/y, HR = 0.18 [95% CI 0.14, 0.25], p < 0.001; P. ovale: 0.06 versus 0.14, HR = 0.31 [95% CI 0.13, 0.77], p = 0.011) and the risk of having at least one clinical P. vivax episode (HR = 0.25 [95% CI 0.11, 0.61], p = 0.002). PQ also reduced the molecular force of P. vivax blood-stage infection in the first 3 mo of follow-up (PQ arm 1.90/y versus PL arm 7.75/y, incidence rate ratio [IRR] = 0.21 [95% CI 0.15, 0.28], p < 0.001). Children who received PQ were less likely to carry P. vivax gametocytes (IRR = 0.27 [95% CI 0.19, 0.38], p < 0.001). PQ had a comparable effect irrespective of the presence of P. vivax blood-stage infection at the time of treatment (p = 0.14). Modelling revealed that mass screening and treatment with highly sensitive quantitative real-time PCR, or MDA with blood-stage treatment alone, would have only a transient effect on P. vivax transmission levels, while MDA that includes liver-stage treatment is predicted to be a highly effective strategy for P. vivax elimination. The inclusion of a directly observed 20-d treatment regime maximises the efficiency of hypnozoite clearance but limits the generalisability of results to real-world MDA programmes. Conclusions These results suggest that relapses cause approximately four of every five P. vivax infections and at least three of every five P. ovale infections in PNG children and are important in sustaining transmission. MDA campaigns combining blood- and liver-stage treatment are predicted to be a highly efficacious intervention for reducing P. vivax and P. ovale transmission. Trial registration ClinicalTrials.gov NCT02143934 PMID:26505753

Rapid diagnostic tests for diagnosing uncomplicated non-falciparum or Plasmodium vivax malaria in endemic countries

PubMed Central

Abba, Katharine; Kirkham, Amanda J; Olliaro, Piero L; Deeks, Jonathan J; Donegan, Sarah; Garner, Paul; Takwoingi, Yemisi

2014-01-01

Background In settings where both Plasmodium vivax and Plasmodium falciparum infection cause malaria, rapid diagnostic tests (RDTs) need to distinguish which species is causing the patients' symptoms, as different treatments are required. Older RDTs incorporated two test lines to distinguish malaria due to P. falciparum, from malaria due to any other Plasmodium species (non-falciparum). These RDTs can be classified according to which antibodies they use: Type 2 RDTs use HRP-2 (for P. falciparum) and aldolase (all species); Type 3 RDTs use HRP-2 (for P. falciparum) and pLDH (all species); Type 4 use pLDH (fromP. falciparum) and pLDH (all species). More recently, RDTs have been developed to distinguish P. vivax parasitaemia by utilizing a pLDH antibody specific to P. vivax. Objectives To assess the diagnostic accuracy of RDTs for detecting non-falciparum or P. vivax parasitaemia in people living in malaria-endemic areas who present to ambulatory healthcare facilities with symptoms suggestive of malaria, and to identify which types and brands of commercial test best detect non-falciparum and P. vivax malaria. Search methods We undertook a comprehensive search of the following databases up to 31 December 2013: Cochrane Infectious Diseases Group Specialized Register; MEDLINE; EMBASE; MEDION; Science Citation Index; Web of Knowledge; African Index Medicus; LILACS; and IndMED. Selection criteria Studies comparing RDTs with a reference standard (microscopy or polymerase chain reaction) in blood samples from a random or consecutive series of patients attending ambulatory health facilities with symptoms suggestive of malaria in non-falciparum endemic areas. Data collection and analysis For each study, two review authors independently extracted a standard set of data using a tailored data extraction form. We grouped comparisons by type of RDT (defined by the combinations of antibodies used), and combined in meta-analysis where appropriate. Average sensitivities and specificities are presented alongside 95% confidence intervals (95% CI). Main results We included 47 studies enrolling 22,862 participants. Patient characteristics, sampling methods and reference standard methods were poorly reported in most studies. RDTs detecting 'non-falciparum' parasitaemia Eleven studies evaluated Type 2 tests compared with microscopy, 25 evaluated Type 3 tests, and 11 evaluated Type 4 tests. In meta-analyses, average sensitivities and specificities were 78% (95% CI 73% to 82%) and 99% (95% CI 97% to 99%) for Type 2 tests, 78% (95% CI 69% to 84%) and 99% (95% CI 98% to 99%) for Type 3 tests, and 89% (95% CI 79% to 95%) and 98% (95% CI 97% to 99%) for Type 4 tests, respectively. Type 4 tests were more sensitive than both Type 2 (P = 0.01) and Type 3 tests (P = 0.03). Five studies compared Type 3 tests with PCR; in meta-analysis, the average sensitivity and specificity were 81% (95% CI 72% to 88%) and 99% (95% CI 97% to 99%) respectively. RDTs detecting P.vivax parasitaemia Eight studies compared pLDH tests to microscopy; the average sensitivity and specificity were 95% (95% CI 86% to 99%) and 99% (95% CI 99% to 100%), respectively. Authors' conclusions RDTs designed to detect P. vivax specifically, whether alone or as part of a mixed infection, appear to be more accurate than older tests designed to distinguish P. falciparum malaria from non-falciparum malaria. Compared to microscopy, these tests fail to detect around 5% ofP. vivax cases. This Cochrane Review, in combination with other published information about in vitro test performance and stability in the field, can assist policy-makers to choose between the available RDTs. PLAIN LANGUAGE SUMMARY Rapid tests for diagnosing malaria caused by Plasmodium vivax or other less common parasites This review summarises trials evaluating the accuracy of rapid diagnostic tests (RDTs) for diagnosing malaria due to Plasmodium vivax or other non-falciparum species. After searching for relevant studies up to December 2013, we included 47 studies, enrolling 22,862 adults and children. What are rapid tests and why do they need to be able to distinguish Plasmodium vivax malaria RDTs are simple to use, point of care tests, suitable for use in rural settings by primary healthcare workers. RDTs work by using antibodies to detect malaria antigens in the patient's blood. A drop of blood is placed on the test strip where the antibodies and antigen combine to create a distinct line indicating a positive test. Malaria can be caused any one of five species of Plasmodium parasite, but P. falciparum and P. vivax are the most common. In some areas, RDTs need to be able to distinguish which species is causing the malaria symptoms as different species may require different treatments. Unlike P. falciparum, P. vivax has a liver stage which can cause repeated illness every few months unless it is treated with primaquine. The most common types of RDTs for P. vivax use two test lines in combination; one line specific to P. falciparum, and one line which can detect any species of Plasmodium. If the P. falciparum line is negative and the 'any species' line is positive, the illness is presumed to be due to P. vivax (but could also be caused by P. malariae, or P. ovale). More recently, RDTs have been developed which specifically test for P. vivax. What does the research say RDTs testing for non-falciparum malaria were very specific (range 98% to 100%) meaning that only 1% to 2% of patients who test positive would actually not have the disease. However, they were less sensitive (range 78% to 89%), meaning between 11% and 22% of people with non-falciparum malaria would actually get a negative test result. RDTs which specifically tested for P. vivax were more accurate with a specificity of 99% and a sensitivity of 95%, meaning that only 5% of people with P. vivax malaria would have a negative test result. PMID:25519857

[Current malaria situation in the Republic of Uzbekistan].

PubMed

Razakov, Sh A; Shakhgunova, G Sh

2001-01-01

Malaria was once one of the most common diseases in Uzbekistan. There were massive epidemics with high mortality rates, wherein 140,000 to 700,000 cases of malaria were recorded. Following large-scale malaria control measures, the disease was eradicated in Uzbekistan in 1961 and the epidemiological situation is still favorable. The natural and climatic conditions that prevail in the Republic of Uzbekistan mean that the country is very susceptible to malaria. There are large water areas varying in type and origin, which provide a habitat for a number of epidemiologically dangerous species of malaria-transmitting mosquitoes in a single area. These are Anopheles maculipennis, An. pulcherrimus and An. superpictus. The prevailing temperatures promote rapid growth of vector mosquitoes and parasites and the malaria transmission season is over 5 months long. Seven malaria-transmitting mosquito species have been recently recorded in the Republic. DDT resistance has been so far noted in Anopheles maculipennis, An. hyrcanus and An. bifurcatus. An. superpictus is sensitive to all insecticides used in clinical practice (organophosphorus and organochlorine compounds, HOS, carbamates, pyrethroids). The most dangerous areas for transmitting malaria by importation are the flood plains of the country's main rivers, such as Syrdarya, Amudarya, Chirchik, Surkhana, etc., and rice-growing areas (an area of about 150,000 ha was under rice cultivation in 1999). The Republic is still very subjected to large-scale importations of malaria particularly in the towns and areas along the border with Tajikistan. There has been recently an increase in the incidence of infections imported into the Republic: 27 cases in 1995, 51 in 1996, 52 in 1997, 74 in 1998, and 78 in 1999. Eight regions of Uzbekistan border Tajikistan, their population is over 5.6 million people. In addition, close family ties between the populations of the frontier towns and regions further increase the risk for malaria to be imported and passed on. Noteworthy is the Surkhandaryin region that accounted for 60% of the cases recorded in 1999. The number of towns and villages where malaria occurs for the first time increased (49 and 46 cases in 1999 and 1998, respectively). The number of cases imported into rural areas also increased (70 (83%) cases in 1999 versus 48 (65%) cases in 1998); due to the large populations of malaria mosquitoes, there is a real danger that the disease may spread. In 1999, most cases of malaria were imported from Tajikistan (65 cases or 76% of all cases). There was a case from each of the following countries: Afghanistan, Pakistan, and Kazakhstan and 5 cases from Azerbaijan and Kyrgyzstan. The recorded cases included slighly more men than women (54% vs 46%). There were 10 infected children under 14 years, which was 23.5% of all notified cases. Analyzing various populations showed that 67.1% of the patients visited their relatives in malaria-endemic countries (mostly Tajikistan) and 25.8% migrated from Tajikistan. All the detected cases were confirmed by laboratory tests. As in the past, most cases were tertian (P. vivax) malaria (n = 82 or 96.4% of all cases). Tropical (P. falciparum) malaria was confirmed in 3 (3.5%) cases. These cases had been imported from Tajikistan into the Surkhandaryin region. Seventy seven (91%) cases were detected in the epidemical season. Of them 58 (68.2%) cases were detected during a malaria transmission season. Seven cases who contacted the patients with imported malaria and were infected were recorded in 1999. They included 4 and 3 cases in the Surkhandaryin and Kashkadaryin Regions, respectively. In 1999, there was a decline in the number of malaria patients who needed health care and in the diagnosed malaria cases in therapeutical and prophylactic institutions. Throughout the country, 34 (40%) of the 85 detected cases presented within 3 days of malaria outbreak (68.9% in 1998). Malaria was immediate diagnosed in 43.5% of cases (64.9% in 1998). The remaining cases were diagnosed as having acute respiratory viral infections, tropical and parasitic diseases, viral hepatitis, or influenza. Early diagnosis of malaria was made in 60% of cases (77% in 1998). Three cases of imported tertian malaria were recorded in the Tashkent Region in the first quarter of 2000. They were imported from Tajikistan into rural areas and the patients had been infected during the 1999 season. Epidemiological surveillance of malaria in Uzbekistan is regularly carried out by the general network of health facilities and by the departments of parasitology of state epidemiological surveillance centers in collaboration with medical administrative departments, the Ministry of Agriculture and Fisheries, the L.M. Isayev Research Institute of Medical Parasitology, and other agencies. Active links are maintained with WHO under the Roll Back Malaria programme. Great emphasis is laid on medical staff training at all levels. During the 1999 epidemiological survey, 672,536 laboratory tests were performed on blood samples from suspected malaria patients and individuals who had visited malaria-endemic countries, 55% of them suffering from fever. A total area of 17 million m2 of dwelling and nondwelling buildings 20 ha of water areas were treated against mosquitoes and the larvivorous fish Gambusia was put into the water areas occupying 6,500 ha. In all cases of malaria, the focus of infection was epidemiologically surveyed and required epidemic preventive measures were implemented. All malaria patients received a full course of radical therapy and recovered completely. The epidemiological surveillance system for malaria is affected by staff shortages at the parasitology departments of state epidemiological surveillance centers and by shortages of microscopes, reagents, sterilizing equipment, insecticides, etc. There are still difficulties in obtaining supplies of primaquine although a small stock is locally available as due to WHO humanitarian assistance. The Epidemiological Malaria Surveillance Programme for the Republic of Uzbekistan for 2000-2004, intended to strengthen the epidemic control capacity of health care facilities, Ministry of Health, is under adoption. The following activities are scheduled for 2000: to plan malaria control activities, including the zoning of the country by the risk of malaria transmission in accordance with republic-leveled directives, instructions, and methodology and WHO recommendations: adjustments to these plans to be made as necessary; to fill vacant posts in the parasitology departments of state epidemiological surveillance centers; to procure stocks of antimalarial drugs, reagents, insecticides, sterilizing equipment, etc., to be paid for from epidemiological service resources; to include malaria issues into certifying tests for physicians, as appropriate for the posts to be occupied and their level of qualifications; to publish posters, brochures, and leaflets about malaria prevention before the malaria transmission season for health education; to hold seminars and meetings for health workers on the etiology of malaria, its clinical features, diagnosis, treatment, and prevention.