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Sample records for falciparum malaria patients

  1. Falciparum malaria-induced hypoglycaemia in a diabetic patient.

    PubMed Central

    Shalev, O.; Tsur, A.; Rahav, G.

    1992-01-01

    We report a patient with diabetes mellitus who suffered severe falciparum malaria complicated by profound and persistent hypoglycaemia. The hypoglycaemia evolved before therapy with quinine was begun and resolved with eradication of the parasitaemia. The patient reverted to her baseline hyperglycaemia despite continuation of quinine. This case illustrates the critical role of falciparum malaria in the pathogenesis of malaria-associated hypoglycaemia, rather than quinine-mediated mechanisms. Anticipation of hypoglycaemia in falciparum malaria and its vigorous treatment may improve the poor prognosis associated with this complication. PMID:1409194

  2. Interactive transcriptome analysis of malaria patients and infecting Plasmodium falciparum.

    PubMed

    Yamagishi, Junya; Natori, Anna; Tolba, Mohammed E M; Mongan, Arthur E; Sugimoto, Chihiro; Katayama, Toshiaki; Kawashima, Shuichi; Makalowski, Wojciech; Maeda, Ryuichiro; Eshita, Yuki; Tuda, Josef; Suzuki, Yutaka

    2014-09-01

    To understand the molecular mechanisms of parasitism in vivo, it is essential to elucidate how the transcriptomes of the human hosts and the infecting parasites affect one another. Here we report the RNA-seq analysis of 116 Indonesian patients infected with the malaria parasite Plasmodium falciparum (Pf). We extracted RNAs from their peripheral blood as a mixture of host and parasite transcripts and mapped the RNA-seq tags to the human and Pf reference genomes to separate the respective tags. We were thus able to simultaneously analyze expression patterns in both humans and parasites. We identified human and parasite genes and pathways that correlated with various clinical data, which may serve as primary targets for drug developments. Of particular importance, we revealed characteristic expression changes in the human innate immune response pathway genes including TLR2 and TICAM2 that correlated with the severity of the malaria infection. We also found a group of transcription regulatory factors, JUND, for example, and signaling molecules, TNFAIP3, for example, that were strongly correlated in the expression patterns of humans and parasites. We also identified several genetic variations in important anti-malaria drug resistance-related genes. Furthermore, we identified the genetic variations which are potentially associated with severe malaria symptoms both in humans and parasites. The newly generated data should collectively lay a unique foundation for understanding variable behaviors of the field malaria parasites, which are far more complex than those observed under laboratory conditions.

  3. Exchange Transfusion in Severe Falciparum Malaria

    PubMed Central

    Khatib, Khalid Ismail

    2016-01-01

    Malaria is endemic in India with the incidence of P. falciparum Malaria increasing gradually over the last decade. Severe malaria is an acute disease, caused by P. falciparum, but increasingly also by P. vivax with major signs of organ dysfunction and/or high levels of parasitaemia (>10%) in blood smear. Use of exchange transfusion with antimalarial drug therapy as an additional modality of treatment in severe Falciparum malaria is controversial and is unclear. We report a case of severe malaria complicated by multiorgan failure and ARDS. Patient responded well to manual exchange transfusion with standard artesunate-based chemotherapy. PMID:27042503

  4. Leukogram Profile and Clinical Status in vivax and falciparum Malaria Patients from Colombia.

    PubMed

    Tobón-Castaño, Alberto; Mesa-Echeverry, Esteban; Miranda-Arboleda, Andrés Felipe

    2015-01-01

    Introduction. Hematological alterations are frequent in malaria patients; the relationship between alterations in white blood cell counts and clinical status in malaria is not well understood. In Colombia, with low endemicity and unstable transmission for malaria, with malaria vivax predominance, the hematologic profile in malaria patients is not well characterized. The aim of this study was to characterize the leukogram in malaria patients and to analyze its alterations in relation to the clinical status. Methods. 888 leukogram profiles of malaria patients from different Colombian regions were studied: 556 with P. falciparum infection (62.6%), 313 with P. vivax infection (35.2%), and 19 with mixed infection by these species (2.1%). Results. Leukocyte counts at diagnosis were within normal range in 79% of patients and 18% had leucopenia; the most frequent alteration was lymphopenia (54%) followed by monocytosis (11%); the differential granulocyte count in 298 patients revealed eosinophilia (15%) and high basophil counts (8%). Leukocytosis, eosinopenia, and neutrophilia were associated with clinical complications. The utility of changes in leukocyte counts as markers of severity should be explored in depth. A better understanding of these hematological parameters will allow their use in prompt diagnosis of malaria complications and monitoring treatment response.

  5. Leukogram Profile and Clinical Status in vivax and falciparum Malaria Patients from Colombia

    PubMed Central

    Tobón-Castaño, Alberto; Mesa-Echeverry, Esteban; Miranda-Arboleda, Andrés Felipe

    2015-01-01

    Introduction. Hematological alterations are frequent in malaria patients; the relationship between alterations in white blood cell counts and clinical status in malaria is not well understood. In Colombia, with low endemicity and unstable transmission for malaria, with malaria vivax predominance, the hematologic profile in malaria patients is not well characterized. The aim of this study was to characterize the leukogram in malaria patients and to analyze its alterations in relation to the clinical status. Methods. 888 leukogram profiles of malaria patients from different Colombian regions were studied: 556 with P. falciparum infection (62.6%), 313 with P. vivax infection (35.2%), and 19 with mixed infection by these species (2.1%). Results. Leukocyte counts at diagnosis were within normal range in 79% of patients and 18% had leucopenia; the most frequent alteration was lymphopenia (54%) followed by monocytosis (11%); the differential granulocyte count in 298 patients revealed eosinophilia (15%) and high basophil counts (8%). Leukocytosis, eosinopenia, and neutrophilia were associated with clinical complications. The utility of changes in leukocyte counts as markers of severity should be explored in depth. A better understanding of these hematological parameters will allow their use in prompt diagnosis of malaria complications and monitoring treatment response. PMID:26664413

  6. Co-infection of human parvovirus B19 with Plasmodium falciparum contributes to malaria disease severity in Gabonese patients

    PubMed Central

    2013-01-01

    Background High seroprevalence of parvovirus B19 (B19V) coinfection with Plasmodium falciparum has been previously reported. However, the impact of B19V-infection on the clinical course of malaria is still elusive. In this study, we investigated the prevalence and clinical significance of B19V co-infection in Gabonese children with malaria. Methods B19V prevalence was analyzed in serum samples of 197 Gabonese children with P. falciparum malaria and 85 healthy controls using polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and direct DNA-sequencing. Results B19V was detected in 29/282 (10.28%) of Gabonese children. B19V was observed more frequently in P. falciparum malaria patients (14.21%) in comparison to healthy individuals (1.17%) (P<0.001). Notably, the mild-malaria group revealed significantly lower hematocrit levels in B19V/P. falciparum co-infection than in P. falciparum mono-infection (P<0.05). Genetic analysis revealed a predominance of B19V genotype-1 (71.43%) in the studied population. However, B19V-genotype 2 was observed significantly more often in children with severe-malaria than in mild-malaria (P=0.04). Conclusion Our findings reveal that B19V-infection is frequent in Gabonese children with P. falciparum malaria and signifies a possible contribution of B19V on the clinical course of malaria in a genotype-dependent manner. B19V co-infection should be considered as a additional diagnostic measure in malaria patients with life threatening anemia. PMID:23945350

  7. Acute renal failure due to falciparum malaria.

    PubMed

    Habte, B

    1990-01-01

    Seventy-two patients with severe falciparum malaria are described. Twenty-four (33.3%) were complicated by acute renal failure. Comparing patients with renal failure and those without, statistically significant differences occurred regarding presence of cerebral malaria (83% vs 46%), jaundice (92% vs 33%), and death (54% vs 17%). A significantly higher number of patients with renal failure were nonimmune visitors to malaria endemic regions. Renal failure was oliguric in 45% of cases. Dialysis was indicated in 38%, 29% died in early renal failure, and 33% recovered spontaneously. It is concluded that falciparum malaria is frequently complicated by cerebral malaria and renal failure. As nonimmune individuals are prone to develop serious complications, malaria prophylaxis and vigorous treatment of cases is mandatory. PMID:2236718

  8. [Relapse of Plasmodium falciparum malaria in a patient treated with artesunate].

    PubMed

    Vandenbos, F; Delaunay, P; Del Giudice, P; Counillon, E

    2006-05-01

    Chemoprophylaxis and the curative treatment of malaria are well documented in France. Nevertheless this data is still not accounted for by healthcare professionals and in the global population, and no longer approved treatments may be prescribed. The authors report the case of a 24-year-old female traveler having stayed in Africa where she was used to treat fever with artesunate. Soon after her return, she presented with uncomplicated Plasmodium falciparum malaria once again treated with artesunate. The evolution was initially favorable but a relapse occurred 3 weeks later. A conventional mefloquine treatment lead to a final cure. This observation confirms that artesunate monotherapy in malaria exposes to a risk of relapse. Artesunate should not be used as monotherapy in P. falciparum malaria. PMID:16697545

  9. Pharmacokinetics and Ex Vivo Pharmacodynamic Antimalarial Activity of Dihydroartemisinin-Piperaquine in Patients with Uncomplicated Falciparum Malaria in Vietnam ▿

    PubMed Central

    Nguyen, Dao Van Hoang; Nguyen, Quoc Phuc; Nguyen, Ngoa Dang; Le, Thuy Thi Thanh; Nguyen, The Duy; Dinh, Duy Ngoc; Nguyen, Thanh Xuan; Bui, Dai; Chavchich, Marina; Edstein, Michael D.

    2009-01-01

    Compared to healthy subjects, malaria patients show a reduction in the mean oral clearance (1.19 versus 5.87 liters/h/kg of body weight) and apparent volume of distribution (1.47 versus 8.02 liters/kg) of dihydroartemisinin in Vietnamese patients following treatment with dihydroartemisinin-piperaquine (Artekin) for uncomplicated Plasmodium falciparum. Dihydroartemisinin is responsible for most of the ex vivo antimalarial activity of dihydroartemisinin-piperaquine. PMID:19528277

  10. Plasma glutamine levels and falciparum malaria.

    PubMed

    Cowan, G; Planche, T; Agbenyega, T; Bedu-Addo, G; Owusu-Ofori, A; Adebe-Appiah, J; Agranoff, D; Woodrow, C; Castell, L; Elford, B; Krishna, S

    1999-01-01

    Glutamine deficiency is associated with increased rates of sepsis and mortality, which can be prevented by glutamine supplementation. Changes in glutamine concentration were examined in Ghanaian children with acute falciparum malaria and control cases. The mean (SD) plasma glutamine concentration was lower in patients with acute malaria (401 (82) mumol/L, n = 50) than in control patients (623 (67) mumol/L, n = 7; P < 0.001). Plasma glutamine concentrations all rose in convalescence. The mean (SD) increase in plasma glutamine was 202 (123) mumol/L (n = 18; P < 0.001) compared with acute infection. We conclude that acute falciparum malaria is associated with large decreases in plasma glutamine and these falls may increase susceptibility to sepsis and dyserythropoeisis.

  11. Immune activation during cerebellar dysfunction following Plasmodium falciparum malaria.

    PubMed

    de Silva, H J; Hoang, P; Dalton, H; de Silva, N R; Jewell, D P; Peiris, J B

    1992-01-01

    Evidence for immune activation was investigated in 12 patients with a rare syndrome of self-limiting, delayed onset cerebellar dysfunction following an attack of falciparum malaria which occurred 18-26 d previously. Concentrations of tumour necrosis factor, interleukin 6 and interleukin 2 were all significantly higher in serum samples of patients during cerebellar ataxia than in recovery sera and in the sera of 8 patients who did not develop delayed cerebellar dysfunction following an attack of falciparum malaria. Cytokine concentrations in the cerebrospinal fluid were also significantly higher in ataxic patients than in controls. These findings suggest that immunological mechanisms may play a role in delayed cerebellar dysfunction following falciparum malaria.

  12. Information Education and Communication can Improve Adherence to Artemether-Lumefantrine Combination in Patients of Uncomplicated Falciparum Malaria

    PubMed Central

    Raulo, Anshupa; Mohapatra, Namita; Singha, Malaya Ranjan

    2015-01-01

    Background Early diagnosis and prompt treatment with Artemisinin combination therapy (ACT) is vital to improve mortality in Falciparum Malaria. Information education and communication (IEC) is a strong tool that can improve drug adherence. Aim To explore if IEC in the form of designed drug bags with verbal communication can improve ACT adherence in Falciparum Malaria patients. Materials and Methods A prospective, interventional, controlled study was conducted in OPD patients of both SCB Medical college, Cuttack and district headquarter hospital Cuttack district of Odisha. IEC material in the form of well designed drug bag and verbal communication was used for intervention. Control group received ACT combinations but were not given IEC. Results Adherence to IEC was significantly higher (81%) in patients receiving IEC compared to controlled patients not receiving IEC. Educational status and the geographical area of the patient were found out to affect adherence to IEC to a significant extent. Conclusion IEC in the form of designed drug bags, supplemented by verbal communication can improve ACT adherence in Falciparum Malaria. PMID:26500920

  13. Two cases of Plasmodium falciparum malaria in the Netherlands without recent travel to a malaria-endemic country.

    PubMed

    Arends, Joop E; Oosterheert, Jan Jelrik; Kraaij-Dirkzwager, Marleen M; Kaan, Jan A; Fanoy, Ewout B; Haas, Pieter-Jan; Scholte, Ernst-Jan; Kortbeek, Laetitia M; Sankatsing, Sanjay U C

    2013-09-01

    Recently, two patients of African origin were given a diagnosis of Plasmodium falciparum malaria without recent travel to a malaria-endemic country. This observation highlights the importance for clinicians to consider tropical malaria in patients with fever. Possible transmission routes of P. falciparum to these patients will be discussed. From a public health perspective, international collaboration is crucial when potential cases of European autochthonous P. falciparum malaria in Europe re considered.

  14. Circulating levels of the interleukin (IL)-4 receptor and of IL-18 in patients with Plasmodium falciparum malaria.

    PubMed

    Perkmann, Thomas; Winkler, Heidi; Graninger, Wolfgang; Kremsner, Peter G; Winkler, Stefan

    2005-02-21

    Circulating levels of sIL-4R, IL-18 and IFN-gamma were studied by ELISA in 36 Gabonese patients with Plasmodium falciparum malaria (29 children, 7 adults). Drug induced clearance of parasitemia, studied in 22 patients with mild disease, was accompanied by a rapid decrease of sIL-4R and IFN-gamma to normal values and an increase of circulating IL-18, suggesting the downregulation of a type 2 biased immune response and a dissociated type 1 responsiveness while resolving parasitemia. Comparing subgroups with hyperparasitemia/severe anemia and mild malaria, children with severe malaria had significant higher levels of sIL-4R and IFN-gamma, whereas IL-18 levels were not statistically different. Furthermore, among those children, higher levels of circulating IL-18 correlated with a lower degree of parasitemia.

  15. Plasmodium Falciparum Malaria

    PubMed Central

    Schmidt, John A.; Udeinya, Iroka J.; Leech, James H.; Hay, Robert J.; Aikawa, Masamichi; Barnwell, John; Green, Ira; Miller, Louis H.

    1982-01-01

    Erythrocytes infected with Plasmodium falciparum trophozoites and schizonts are not seen in the peripheral circulation because they attach to venular endothelium via knoblike structures on the infected erythrocyte membrane. We have recently shown that erythrocytes containing P. falciparum trophozoites and schizonts likewise attach to cultured human venous endothelial cells via knobs. In search of a more practical target cell for large scale binding studies designed to characterize and isolate the knob ligand, we tested various normal cells and continuous cell lines for their ability to bind P. falciparum-infected erythrocytes. Of the 18 cell types tested, binding of infected erythrocytes was observed to a human amelanotic melanoma cell line and amnion epithelial cells as well as to human aortic and umbilical vein endothelial cells. 96-100% of amelanotic melanoma cells bound 17±4 (±1 SEM) infected erythrocytes per positive cell, whereas fewer endothelial cells (4-59%) and amnion epithelial cells (8-19%) were capable of binding 12±5 and 4±1 infected erythrocytes per positive cell, respectively. Further studies designed to compare the mechanism of binding to the amelanotic melanoma cell line and endothelial cells showed the following results. First, that adhesion of infected erythrocytes to these two cell types was parasite stage-specific in that only erythrocytes containing late ring forms, trophozoites, and schizonts bound. Erythrocytes containing early ring forms, which do not attach to venular endothelium in vivo, did not bind to either cell type. Second, erythrocytes infected with trophozoites and schizonts of P. vivax or a knobless strain of P. falciparum, both of which continue to circulate in vivo, did not bind to either target cell type. Third, transmission electron microscopy showed that infected erythrocytes attached to the amelanotic melanoma cells via knobs. We conclude that cultured human endothelial cells and an amelanotic melanoma cell line share

  16. Proteomic analysis of Plasmodium falciparum parasites from patients with cerebral and uncomplicated malaria

    PubMed Central

    Bertin, Gwladys I.; Sabbagh, Audrey; Argy, Nicolas; Salnot, Virginie; Ezinmegnon, Sem; Agbota, Gino; Ladipo, Yélé; Alao, Jules M.; Sagbo, Gratien; Guillonneau, François; Deloron, Philippe

    2016-01-01

    Plasmodium falciparum is responsible of severe malaria, including cerebral malaria (CM). During its intra-erythrocytic maturation, parasite-derived proteins are expressed, exported and presented at the infected erythrocyte membrane. To identify new CM-specific parasite membrane proteins, we conducted a mass spectrometry-based proteomic study and compared the protein expression profiles between 9 CM and 10 uncomplicated malaria (UM) samples. Among the 1097 Plasmodium proteins identified, we focused on the 499 membrane-associated and hypothetical proteins for comparative analysis. Filter-based feature selection methods combined with supervised data analysis identified a subset of 29 proteins distinguishing CM and UM samples with high classification accuracy. A hierarchical clustering analysis of these 29 proteins based on the similarity of their expression profiles revealed two clusters of 15 and 14 proteins, respectively under- and over-expressed in CM. Among the over-expressed proteins, the MESA protein is expressed at the erythrocyte membrane, involved in proteins trafficking and in the export of variant surface antigens (VSAs), but without antigenic function. Antigen 332 protein is exported at the erythrocyte, also involved in protein trafficking and in VSAs export, and exposed to the immune system. Our proteomics data demonstrate an association of selected proteins in the pathophysiology of CM. PMID:27245217

  17. Plasma Concentration of Parasite DNA as a Measure of Disease Severity in Falciparum Malaria

    PubMed Central

    Imwong, Mallika; Woodrow, Charles J.; Hendriksen, Ilse C. E.; Veenemans, Jacobien; Verhoef, Hans; Faiz, M. Abul; Mohanty, Sanjib; Mishra, Saroj; Mtove, George; Gesase, Samwel; Seni, Amir; Chhaganlal, Kajal D.; Day, Nicholas P. J.; Dondorp, Arjen M.; White, Nicholas J.

    2015-01-01

    In malaria-endemic areas, Plasmodium falciparum parasitemia is common in apparently healthy children and severe malaria is commonly misdiagnosed in patients with incidental parasitemia. We assessed whether the plasma Plasmodium falciparum DNA concentration is a useful datum for distinguishing uncomplicated from severe malaria in African children and Asian adults. P. falciparum DNA concentrations were measured by real-time polymerase chain reaction (PCR) in 224 African children (111 with uncomplicated malaria and 113 with severe malaria) and 211 Asian adults (100 with uncomplicated malaria and 111 with severe malaria) presenting with acute falciparum malaria. The diagnostic accuracy of plasma P. falciparum DNA concentrations in identifying severe malaria was 0.834 for children and 0.788 for adults, similar to that of plasma P. falciparum HRP2 levels and substantially superior to that of parasite densities (P < .0001). The diagnostic accuracy of plasma P. falciparum DNA concentrations plus plasma P. falciparum HRP2 concentrations was significantly greater than that of plasma P. falciparum HRP2 concentrations alone (0.904 for children [P = .004] and 0.847 for adults [P = .003]). Quantitative real-time PCR measurement of parasite DNA in plasma is a useful method for diagnosing severe falciparum malaria on fresh or archived plasma samples. PMID:25344520

  18. Spontaneous rupture of spleen in falciparum malaria.

    PubMed

    Vidyashankar, C; Basu, Arup; Kulkarni, A R; Choudhury, R K

    2003-01-01

    Spontaneous rupture of spleen is an extremely rare complication of falciparum malaria. We report a 3 1/2-year-old girl with splenic rupture who was managed successfully with splenectomy and antimalarials.

  19. [Plasmodium falciparum malaria: epidemiology and clinical features at Tarapoto Hospital].

    PubMed

    Calderon, J; Rodriguez, J; Romero, D

    1997-01-01

    A retrospective study was conducted of the clinical records of 41 patients discharged from a hospital in Tarapoto, Peru, between August 1992 and June 1996 following treatment for Plasmodium falciparum malaria. Patients ranged in age from 18 to 65 years; 25 were male. The cases were uniformly distributed throughout the year. The duration of illness averaged 11 days. At admission, 40 patients had fever, 36 had shaking chills, 29 had headache, 21 had nausea and vomiting, 21 had hyporexia, 15 had pallor, and 13 had splenomegaly. 3 of the 16 women were pregnant. 7 patients reported a history of malaria. The admission diagnosis was malaria in 33 cases. 31 patients were treated with chloroquine; 18 were subsequently treated with pyrimethamine-sulfadoxin and 1 received doxycycline. No cases of grave illness or death occurred. The increasing presence of Plasmodium falciparum malaria in the Peruvian lowlands should promote review of the adequacy of control programs.

  20. Fosmidomycin plus Clindamycin for Treatment of Pediatric Patients Aged 1 to 14 Years with Plasmodium falciparum Malaria

    PubMed Central

    Borrmann, Steffen; Lundgren, Ingrid; Oyakhirome, Sunny; Impouma, Bénido; Matsiegui, Pierre-Blaise; Adegnika, Ayola A.; Issifou, Saadou; Kun, Jürgen F. J.; Hutchinson, David; Wiesner, Jochen; Jomaa, Hassan; Kremsner, Peter G.

    2006-01-01

    Fosmidomycin plus clindamycin was shown to be efficacious in the treatment of uncomplicated Plasmodium falciparum malaria in a small cohort of pediatric patients aged 7 to 14 years, but more data, including data on younger children with less antiparasitic immunity, are needed to determine the potential value of this new antimalarial combination. We conducted a single-arm study to improve the precision of efficacy estimates for an oral 3-day fixed-ratio combination of fosmidomycin and clindamycin at 30 and 10 mg/kg of body weight, respectively, every 12 hours for the treatment of uncomplicated P. falciparum malaria in 51 pediatric outpatients aged 1 to 14 years. Fosmidomycin plus clindamycin was generally well tolerated, but relatively high rates of treatment-associated neutropenia (8/51 [16%]) and falls of hemoglobin concentrations of ≥2 g/dl (7/51 [14%]) are of concern. Asexual parasites and fever were cleared within median periods of 42 h and 38 h, respectively. All patients who could be evaluated were parasitologically and clinically cured by day 14 (49/49; 95% confidence interval [CI], 93 to 100%). The per-protocol, PCR-adjusted day 28 cure rate was 89% (42/47; 95% CI, 77 to 96%). Efficacy appeared to be significantly reduced in children aged 1 to 2 years, with a day 28 cure rate of only 62% for this small subgroup (5/8). The inadequate efficacy in children of <3 years highlights the need for continued systematic studies of the current dosing regimen, which should include randomized trial designs. PMID:16870763

  1. Quantification of Plasmodium falciparum histidine-rich protein-2 in cerebrospinal spinal fluid from cerebral malaria patients.

    PubMed

    Mikita, Kei; Thakur, Kiran; Anstey, Nicholas M; Piera, Kim A; Pardo, Carlos A; Weinberg, J Brice; Mukemba, Jackson; Florence, Salvatore; Mwaikambo, Esther D; Granger, Donald L; Sullivan, David J

    2014-09-01

    A cerebrospinal fluid (CSF) biomarker for cerebral malaria (CM) has not been validated. We examined the detection, semiquantification, and clinical use of the Plasmodium falciparum histidine-rich protein-2 (PfHRP-2) as a parasite antigen biomarker for CM. The PfHRP-2 was detected in archival CSF samples from CM patients from Tanzania both by a newly developed sensitive and specific immuno-polymerase chain reaction (72 of 73) and by rapid diagnostic tests (62 of 73). The geometric mean PfHRP-2 CSF concentration was 8.76 ng/mL with no differences in those who survived (9.2 ng/mL), those who died (11.1 ng/mL), and those with neurologic sequelae (10.8 ng/mL). All aparasitemic endemic and nonendemic control samples had undetectable CSF PfHRP-2. In a separate group of 11 matched plasma and CSF cerebral malaria patient samples, the ratio of plasma to CSF PfHRP-2 was 175. The CSF PfHRP-2 reflects elevated plasma PfHRP-2 rather than elevated CM-specific CSF ratios, falling short of a validated biomarker.

  2. Artemisinin-resistant Plasmodium falciparum malaria

    PubMed Central

    Fairhurst, Rick M.; Dondorp, Arjen M.

    2016-01-01

    For more than five decades, Southeast Asia (SEA) has been fertile ground for the emergence of drug-resistant Plasmodium falciparum malaria. After generating parasites resistant to chloroquine, sulfadoxine, pyrimethamine, quinine, and mefloquine, this region has now spawned parasites resistant to artemisinins – the world's most potent antimalarial drugs. In areas where artemisinin resistance is prevalent, artemisinin combination therapies (ACTs) – the first-line treatments for malaria – are failing fast. This worrisome development threatens to make malaria practically untreatable in SEA, and threatens to compromise global endeavors to eliminate this disease. A recent series of clinical, in-vitro, genomics, and transcriptomics studies in SEA have defined in-vivo and in-vitro phenotypes of artemisinin resistance; identified its causal genetic determinant; explored its molecular mechanism; and assessed its clinical impact. Specifically, these studies have established that artemisinin resistance manifests as slow parasite clearance in patients and increased survival of early ring-stage parasites in vitro; is caused by single nucleotide polymorphisms in the parasite's ‘K13’ gene; is associated with an upregulated “unfolded protein response” pathway that may antagonize the pro-oxidant activity of artemisinins; and selects for partner drug resistance that rapidly leads to ACT failures. In SEA, clinical studies are urgently needed to monitor ACT efficacy where K13 mutations are prevalent; test whether new combinations of currently-available drugs cure ACT failures; and advance new antimalarial compounds through preclinical pipelines and into clinical trials. Intensifying these efforts should help to forestall the spread of artemisinin and partner drug resistance from SEA to Sub-Saharan Africa, where the world's malaria transmission, morbidity, and mortality rates are highest. PMID:27337450

  3. Multiple dose pharmacokinetics of oral artemisinin and comparison of its efficacy with that of oral artesunate in falciparum malaria patients.

    PubMed

    Hassan Alin, M; Ashton, M; Kihamia, C M; Mtey, G J; Björkman, A

    1996-01-01

    The study compared the clinical efficacy and safety of oral artemisinin and oral artesunate as well as artemisinin pharmacokinetics during and after resolution of falciparum malaria. Forty adults with symptomatic falciparum malaria were allocated at random to treatment with either oral artemisinin (500 mg single dose on day 1 followed by 250 mg twice daily for 4 d and then another 500 mg single dose on day 6) or with oral artesunate (100 mg single dose on day 1 followed by 50 mg twice daily for 5 d). Patients were admitted to hospital at the Kibaha Designated District Hospital, Kibaha, Tanzania for the duration of treatment. The patients were seen once weekly for 3 more weeks. The time to parasite clearance (PCT) after oral artesunate (26.4 +/- 3.6 h) was shorter (P = 0.002) than after artemisinin (31 +/- 3.6 h). The fever subsidence time (FST) after oral artesunate (18.9 +/- 4.0 h) was also shorter (P = 0.04) than after artemisinin (21.8 +/- 4.6 h). Parasites were detected in 4 (20%) and 7 (35%) patients after completing treatment with artesunate and artemisinin respectively. In these patients the parasitaemia reappeared at the 3rd or 4th week of follow-up. Standard haematology, blood biochemistry and urinalysis, performed before drug intake and again on days 6 and 14, were normal. No clinical abnormality was observed during the study period. Artemisinin plasma concentrations, determined by high performance liquid chromatography with post-column derivatization and detection by ultraviolet light, were followed up to 8 h after drug administration on days 1 and 6. Artemisinin absorption was rapid, the maximum plasma concentrations (Cmax) being attained at about 3 h. Artemisinin areas under the plasma concentration-time curve (AUC) and the Cmax values were about 6 times higher after the first dose on day 1 than on day 6. This decrease in artemisinin plasma concentration is suggestive of an increase in metabolic capacity due to pronounced autoinduction.

  4. Antimalarial Activity of KAF156 in Falciparum and Vivax Malaria.

    PubMed

    White, Nicholas J; Duong, Tran T; Uthaisin, Chirapong; Nosten, François; Phyo, Aung P; Hanboonkunupakarn, Borimas; Pukrittayakamee, Sasithon; Jittamala, Podjanee; Chuthasmit, Kittiphum; Cheung, Ming S; Feng, Yiyan; Li, Ruobing; Magnusson, Baldur; Sultan, Marc; Wieser, Daniela; Xun, Xiaolei; Zhao, Rong; Diagana, Thierry T; Pertel, Peter; Leong, F Joel

    2016-09-22

    Background KAF156 belongs to a new class of antimalarial agents (imidazolopiperazines), with activity against asexual and sexual blood stages and the preerythrocytic liver stages of malarial parasites. Methods We conducted a phase 2, open-label, two-part study at five centers in Thailand and Vietnam to assess the antimalarial efficacy, safety, and pharmacokinetic profile of KAF156 in adults with acute Plasmodium vivax or P. falciparum malaria. Assessment of parasite clearance rates in cohorts of patients with vivax or falciparum malaria who were treated with multiple doses (400 mg once daily for 3 days) was followed by assessment of the cure rate at 28 days in a separate cohort of patients with falciparum malaria who received a single dose (800 mg). Results Median parasite clearance times were 45 hours (interquartile range, 42 to 48) in 10 patients with falciparum malaria and 24 hours (interquartile range, 20 to 30) in 10 patients with vivax malaria after treatment with the multiple-dose regimen and 49 hours (interquartile range, 42 to 54) in 21 patients with falciparum malaria after treatment with the single dose. Among the 21 patients who received the single dose and were followed for 28 days, 1 had reinfection and 7 had recrudescent infections (cure rate, 67%; 95% credible interval, 46 to 84). The mean (±SD) KAF156 terminal elimination half-life was 44.1±8.9 hours. There were no serious adverse events in this small study. The most common adverse events included sinus bradycardia, thrombocytopenia, hypokalemia, anemia, and hyperbilirubinemia. Vomiting of grade 2 or higher occurred in 2 patients, 1 of whom discontinued treatment because of repeated vomiting after receiving the single 800-mg dose. More adverse events were reported in the single-dose cohort, which had longer follow-up, than in the multiple-dose cohorts. Conclusions KAF156 showed antimalarial activity without evident safety concerns in a small number of adults with uncomplicated P. vivax or P

  5. Efficacy of chloroquine for the treatment of uncomplicated Plasmodium falciparum malaria in Honduras.

    PubMed

    Mejia Torres, Rosa Elena; Banegas, Engels Ilich; Mendoza, Meisy; Diaz, Cesar; Bucheli, Sandra Tamara Mancero; Fontecha, Gustavo A; Alam, Md Tauqeer; Goldman, Ira; Udhayakumar, Venkatachalam; Zambrano, Jose Orlinder Nicolas

    2013-05-01

    Chloroquine (CQ) is officially used for the primary treatment of Plasmodium falciparum malaria in Honduras. In this study, the therapeutic efficacy of CQ for the treatment of uncomplicated P. falciparum malaria in the municipality of Puerto Lempira, Gracias a Dios, Honduras was evaluated using the Pan American Health Organization-World Health Organization protocol with a follow-up of 28 days. Sixty-eight patients from 6 months to 60 years of age microscopically diagnosed with uncomplicated P. falciparum malaria were included in the final analysis. All patients who were treated with CQ (25 mg/kg over 3 days) cleared parasitemia by day 3 and acquired no new P. falciparum infection within 28 days of follow-up. All the parasite samples sequenced for CQ resistance mutations (pfcrt) showed only the CQ-sensitive genotype (CVMNK). This finding shows that CQ remains highly efficacious for the treatment of uncomplicated P. falciparum malaria in Gracias a Dios, Honduras.

  6. Natural antisense transcripts in Plasmodium falciparum isolates from patients with complicated malaria.

    PubMed

    Subudhi, Amit Kumar; Boopathi, P A; Garg, Shilpi; Middha, Sheetal; Acharya, Jyoti; Pakalapati, Deepak; Saxena, Vishal; Aiyaz, Mohammed; Orekondy, Harsha B; Mugasimangalam, Raja C; Sirohi, Paramendra; Kochar, Sanjay K; Kochar, Dhanpat K; Das, Ashis

    2014-06-01

    Mechanisms regulating gene expression in malaria parasites are not well understood. Little is known about how the parasite regulates its gene expression during transition from one developmental stage to another and in response to various environmental conditions. Parasites in a diseased host face environments which differ from the static, well adapted in vitro conditions. Parasites thus need to adapt quickly and effectively to these conditions by establishing transcriptional states which are best suited for better survival. With the discovery of natural antisense transcripts (NATs) in this parasite and considering the various proposed mechanisms by which NATs might regulate gene expression, it has been speculated that these might be playing a critical role in gene regulation. We report here the diversity of NATs in this parasite, using isolates taken directly from patients with differing clinical symptoms caused by malaria infection. Using a custom designed strand specific whole genome microarray, a total of 797 NATs targeted against annotated loci have been detected. Out of these, 545 NATs are unique to this study. The majority of NATs were positively correlated with the expression pattern of the sense transcript. However, 96 genes showed a change in sense/antisense ratio on comparison between uncomplicated and complicated disease conditions. The antisense transcripts map to a broad range of biochemical/metabolic pathways, especially pathways pertaining to the central carbon metabolism and stress related pathways. Our data strongly suggests that a large group of NATs detected here are unannotated transcription units antisense to annotated gene models. The results reveal a previously unknown set of NATs that prevails in this parasite, their differential regulation in disease conditions and mapping to functionally well annotated genes. The results detailed here call for studies to deduce the possible mechanism of action of NATs, which would further help in

  7. Pharmacokinetics of benflumetol given as a fixed combination artemether-benflumetol (CGP 56697) in Thai patients with uncomplicated falciparum malaria.

    PubMed

    Na-Bangchang, K; Karbwang, J; Tasanor, U; Thanavibul, A; Farkad, E; Mull, R

    1999-01-01

    The pharmacokinetics of benflumetol as a fixed combination, artemether-benflumetol (CGP 56697), following three regimens [regimen A: four tablets at 0, 8, 24 and 48 h (320 mg artemether, 1,920 mg benflumetol); regimen B: two tablets at 0, 8, 24 and 48 h (160 mg artemether, 960 mg benflumetol); regimen C: four tablets at 0, 8 and 24 h (240 mg artemether, 1,440 mg benflumetol)] were investigated in 39 patients with acute uncomplicated falciparum malaria. All patients showed a rapid initial response with a median parasite clearance time of 40, 41 and 39.5 h and a fever clearance time of 27.8, 32 and 24.5 h for regimens A, B and C, respectively. In nine patients (two, four and three patients in regimens A, B and C, respectively), however, parasitemia reappeared in the peripheral blood smear between days 9 and 23. The pharmacokinetics of benflumetol were highly variable, with coefficients of variation in pharmacokinetic parameters ranging from 14.9% to 144%. Absorption and elimination of benflumetol were relatively slow. Median Cmax per dose (first dose) was significantly higher in regimen B (6.29 ng/ml/mg dose) than in regimen A (2.6 ng/ml/mg dose) and regimen C (3.06 ng/ml/mg dose). Mean T1/2z in regimen C (2.65 h) was significantly shorter than in regimen A (4.5 h) and regimen B (3.89 h). In patients on regimens A and B who showed a sensitive response, plasma concentrations of benflumetol were significantly higher than in those with treatment failure.

  8. Dynamic alteration in splenic function during acute falciparum malaria

    SciTech Connect

    Looareesuwan, S.; Ho, M.; Wattanagoon, Y.; White, N.J.; Warrell, D.A.; Bunnag, D.; Harinasuta, T.; Wyler, D.J.

    1987-09-10

    Plasmodium-infected erythrocytes lose their normal deformability and become susceptible to splenic filtration. In animal models, this is one mechanism of antimalarial defense. To assess the effect of acute falciparum malaria on splenic filtration, we measured the clearance of heated /sup 51/Cr-labeled autologous erythrocytes in 25 patients with acute falciparum malaria and in 10 uninfected controls. Two groups of patients could be distinguished. Sixteen patients had splenomegaly, markedly accelerated clearance of the labeled erythrocytes (clearance half-time, 8.4 +/- 4.4 minutes (mean +/- SD) vs. 62.5 +/- 36.5 minutes in controls; P less than 0.001), and a lower mean hematocrit than did the patients without splenomegaly (P less than 0.001). In the nine patients without splenomegaly, clearance was normal. After institution of antimalarial chemotherapy, however, the clearance in this group accelerated to supernormal rates similar to those in the patients with splenomegaly, but without the development of detectable splenomegaly. Clearance was not significantly altered by treatment in the group with splenomegaly. Six weeks later, normal clearance rates were reestablished in most patients in both groups. We conclude that splenic clearance of labeled erythrocytes is enhanced in patients with malaria if splenomegaly is present and is enhanced only after treatment if splenomegaly is absent. Whether this enhanced splenic function applies to parasite-infected erythrocytes in patients with malaria and has any clinical benefit will require further studies.

  9. [Is Plasmodium falciparum, the parasite responsible for tropical malaria, resistant to fansidar?].

    PubMed

    Holzer, B; Keller, H; Frossard, E; Stürchler, D

    1980-03-01

    A world-wide increase of malaria infections is observed. Malaria is imported into Switzerland mainly by tourists and recently by refugees from South East Asia. The strains of P. falciparum resistant to treatment are of increasing importance. A patient with P. falciparum infection from Cambodia is reported, who suffered from three episodes of malaria recrudescence within ten weeks, in spite of adequate therapy with quinine and Fansidar. The definition, the significance and the geographical distribution of resistances and the possible cause for a P. falciparum recrudescence are discussed. For the treatment of repeating recrudescence quinine and Fansidar are recommended, followed by a suppressive Fansidar prophylaxy for 4--8 weeks.

  10. Pharmacokinetic-Pharmacodynamic Model for the Effect of l-Arginine on Endothelial Function in Patients with Moderately Severe Falciparum Malaria

    PubMed Central

    Brussee, Janneke M.; Yeo, Tsin W.; Lampah, Daniel A.; Anstey, Nicholas M.

    2015-01-01

    Impaired organ perfusion in severe falciparum malaria arises from microvascular sequestration of parasitized cells and endothelial dysfunction. Endothelial dysfunction in malaria is secondary to impaired nitric oxide (NO) bioavailability, in part due to decreased plasma concentrations of l-arginine, the substrate for endothelial cell NO synthase. We quantified the time course of the effects of adjunctive l-arginine treatment on endothelial function in 73 patients with moderately severe falciparum malaria derived from previous studies. Three groups of 10 different patients received 3 g, 6 g, or 12 g of l-arginine as a half-hour infusion. The remaining 43 received saline placebo. A pharmacokinetic-pharmacodynamic (PKPD) model was developed to describe the time course of changes in exhaled NO concentrations and reactive hyperemia-peripheral arterial tonometry (RH-PAT) index values describing endothelial function and then used to explore optimal dosing regimens for l-arginine. A PK model describing arginine concentrations in patients with moderately severe malaria was extended with two pharmacodynamic biomeasures, the intermediary biochemical step (NO production) and endothelial function (RH-PAT index). A linear model described the relationship between arginine concentrations and exhaled NO. NO concentrations were linearly related to RH-PAT index. Simulations of dosing schedules using this PKPD model predicted that the time within therapeutic range would increase with increasing arginine dose. However, simulations demonstrated that regimens of continuous infusion over longer periods would prolong the time within the therapeutic range even more. The optimal dosing regimen for l-arginine is likely to be administration schedule dependent. Further studies are necessary to characterize the effects of such continuous infusions of l-arginine on NO and microvascular reactivity in severe malaria. PMID:26482311

  11. Pharmacokinetic-Pharmacodynamic Model for the Effect of l-Arginine on Endothelial Function in Patients with Moderately Severe Falciparum Malaria.

    PubMed

    Brussee, Janneke M; Yeo, Tsin W; Lampah, Daniel A; Anstey, Nicholas M; Duffull, Stephen B

    2016-01-01

    Impaired organ perfusion in severe falciparum malaria arises from microvascular sequestration of parasitized cells and endothelial dysfunction. Endothelial dysfunction in malaria is secondary to impaired nitric oxide (NO) bioavailability, in part due to decreased plasma concentrations of l-arginine, the substrate for endothelial cell NO synthase. We quantified the time course of the effects of adjunctive l-arginine treatment on endothelial function in 73 patients with moderately severe falciparum malaria derived from previous studies. Three groups of 10 different patients received 3 g, 6 g, or 12 g of l-arginine as a half-hour infusion. The remaining 43 received saline placebo. A pharmacokinetic-pharmacodynamic (PKPD) model was developed to describe the time course of changes in exhaled NO concentrations and reactive hyperemia-peripheral arterial tonometry (RH-PAT) index values describing endothelial function and then used to explore optimal dosing regimens for l-arginine. A PK model describing arginine concentrations in patients with moderately severe malaria was extended with two pharmacodynamic biomeasures, the intermediary biochemical step (NO production) and endothelial function (RH-PAT index). A linear model described the relationship between arginine concentrations and exhaled NO. NO concentrations were linearly related to RH-PAT index. Simulations of dosing schedules using this PKPD model predicted that the time within therapeutic range would increase with increasing arginine dose. However, simulations demonstrated that regimens of continuous infusion over longer periods would prolong the time within the therapeutic range even more. The optimal dosing regimen for l-arginine is likely to be administration schedule dependent. Further studies are necessary to characterize the effects of such continuous infusions of l-arginine on NO and microvascular reactivity in severe malaria.

  12. Delayed Diagnosis of Falciparum Malaria with Acute Kidney Injury.

    PubMed

    Choi, Iee Ho; Hwang, Pyoung Han; Choi, Sam Im; Lee, Dae Yeol; Kim, Min Sun

    2016-09-01

    Prompt malaria diagnosis is crucial so antimalarial drugs and supportive care can then be rapidly initiated. A 15-year-old boy who had traveled to Africa (South Africa, Kenya, and Nigeria between January 3 and 25, 2011) presented with fever persisting over 5 days, headache, diarrhea, and dysuria, approximately 17 days after his return from the journey. Urinalysis showed pyuria and hematuria. Blood examination showed hemolytic anemia, thrombocytopenia, disseminated intravascular coagulation, and hyperbilirubinemia. Plasmapheresis and hemodialysis were performed for 19 hospital days. Falciparum malaria was then confirmed by peripheral blood smear, and antimalarial medications were initiated. The patient's condition and laboratory results were quickly normalized. We report a case of severe acute renal failure associated with delayed diagnosis of falciparum malaria, and primary use of supportive treatment rather than antimalarial medicine. The present case suggests that early diagnosis and treatment is important because untreated tropical malaria can be associated with severe acute renal failure and fatality. Physicians must be alert for correct diagnosis and proper management of imported tropical malaria when patients have travel history of endemic areas. PMID:27510397

  13. [Plasmodium falciparum malaria: evaluation of three imported cases].

    PubMed

    İnkaya, Ahmet Çağkan; Kaya, Filiz; Yıldız, İrem; Uzun, Ömrüm; Ergüven, Sibel

    2016-04-01

    Among Plasmodium species the causative agent of malaria in Turkey is P.vivax, however the incidence of imported falciparum malaria cases is steadily increasing. P.falciparum may cause severe malaria with the involvement of central nervous system, acute renal failure, severe anemia or acute respiratory distress syndrome. Furhermore most of the casualties due to malaria are related with P.falciparum. There is recently, a considerable increase in malaria infections especially in tropical areas. In this report, three cases, who have admitted to our hospital with three different clinical presentations of falciparum malaria, and all shared common history of travelling to Africa were presented. First case was a 27 years old, male patient who returned from Malawi seven days ago where he stayed for two weeks. He admitted to our hospital with the complaints of sensation of cold, shivering and fever. In physical examination his body temperature was 37.9°C, C-reactive protein level was high, and the other systemic results were normal. The second case was a 25 years old, male patient who returned from Gambia two weeks ago. He was suffering from fever, headache, shivering and unable to maintain his balance. The patient's body temperature was 38°C. Laboratory tests revealed hyperbilirubinemia and thrombocytopenia. Parasitological examination of the Giemsa-stained peripheral blood smear of these two patients demonstrated ring forms compatible with P.falciparum. Treatment was commenced with arthemeter plus lumefantrine, resulting with complete cure. Third case was a 46 years old, male patient who had been working in Uganda, and returned to Turkey two weeks ago. He had sudden onset of fever, headache, nausea and vomiting and impaired consciousness. His peripheral blood smear revealed ring-formed trophozoites and banana-shaped gametocytes of P.falciparum. Arthemeter plus lumefantrine therapy was started, however, he developed severe thrombocytopenia and jaundice under treatment

  14. Antimalarial activity of artefenomel (OZ439), a novel synthetic antimalarial endoperoxide, in patients with Plasmodium falciparum and Plasmodium vivax malaria: an open-label phase 2 trial

    PubMed Central

    Phyo, Aung Pyae; Jittamala, Podjanee; Nosten, François H; Pukrittayakamee, Sasithon; Imwong, Mallika; White, Nicholas J; Duparc, Stephan; Macintyre, Fiona; Baker, Mark; Möhrle, Jörg J

    2016-01-01

    Summary Background Artefenomel (OZ439) is a novel synthetic trioxolane with improved pharmacokinetic properties compared with other antimalarial drugs with the artemisinin pharmacophore. Artefenomel has been generally well tolerated in volunteers at doses up to 1600 mg and is being developed as a partner drug in an antimalarial combination treatment. We investigated the efficacy, tolerability, and pharmacokinetics of artefenomel at different doses in patients with Plasmodium falciparum or Plasmodium vivax malaria. Methods This phase 2a exploratory, open-label trial was done at the Hospital for Tropical Diseases, Bangkok, and the Shoklo Malaria Research Unit in Thailand. Adult patients with acute, uncomplicated P falciparum or P vivax malaria received artefenomel in a single oral dose (200 mg, 400 mg, 800 mg, or 1200 mg). The first cohort received 800 mg. Testing of a new dose of artefenomel in a patient cohort was decided on after safety and efficacy assessment of the preceding cohort. The primary endpoint was the natural log parasite reduction per 24 h. Definitive oral treatment was given at 36 h. This trial is registered with ClinicalTrials.gov, number NCT01213966. Findings Between Oct 24, 2010, and May 25, 2012, 82 patients were enrolled (20 in each of the 200 mg, 400 mg, and 800 mg cohorts, and 21 in the 1200 mg cohort). One patient withdrew consent (before the administration of artefenomel) but there were no further dropouts. The parasite reduction rates per 24 h ranged from 0·90 to 1·88 for P falciparum, and 2·09 to 2·53 for P vivax. All doses were equally effective in both P falciparum and P vivax malaria, with median parasite clearance half-lives of 4·1 h (range 1·3–6·7) to 5·6 h (2·0–8·5) for P falciparum and 2·3 h (1·2–3·9) to 3·2 h (0·9–15·0) for P vivax. Maximum plasma concentrations, dose-proportional to 800 mg, occurred at 4 h (median). The estimated elimination half-life was 46–62 h. No serious drug-related adverse effects

  15. Genetic polymorphism of merozoite surface protein-1 in Plasmodium falciparum isolates from patients with mild to severe malaria in Libreville, Gabon.

    PubMed

    Bouyou-Akotet, Marielle Karine; M'Bondoukwé, Noé Patrick; Mawili-Mboumba, Denise Patricia

    2015-01-01

    We assessed Plasmodium (P.) falciparum allelic diversity based on clinical severity and age. The study was conducted from 2011 to 2012 in Libreville, Gabon where malaria prevalence was 24.5%. The polymorphism of the merozoite surface protein-1 (msp1) locus was analyzed in isolates from patients with complicated and uncomplicated malaria. Blood was collected on filter paper. After DNA extraction, genotyping of the msp1 gene was performed using nested PCR. The K1, Ro33, and Mad20 allelic families were detected in 71 (63%), 64 (57%), and 38 (34%) of the 112 analyzed samples, respectively. Overall, 17 K1 and 11 Mad20 alleles were detected. There was no association between msp1 allelic families and age. Mad20 allelic diversity increased with the severity of malaria. The number of K1 and Mad20 alleles decreased with age. The multiplicity of infection (MOI) was 1-6 genotypes and the complexity of infection (COI) 1.8 ± 1. The COI differed based on age: it was 1.9 (±1.1) in the isolates from adults, 1.8 (±1.1) in those from 0-5 year-old children, whereas it tended to be lower (1.6 ± 0.8) in those from 6-15 year-old children. Extensive genetic diversity is found in P. falciparum strains circulating in Libreville. The number of specific msp1 alleles increased with clinical severity, suggesting an association between the diversity and the severity of malaria.

  16. High Frequency of Clinically Significant Bacteremia in Adults Hospitalized With Falciparum Malaria.

    PubMed

    Nyein, Phyo Pyae; Aung, Ne Myo; Kyi, Tint Tint; Htet, Zaw Win; Anstey, Nicholas M; Kyi, Mar Mar; Hanson, Josh

    2016-01-01

    Background.  African children with severe falciparum malaria commonly have concomitant Gram-negative bacteremia, but co-infection has been thought to be relatively rare in adult malaria. Methods.  Adults with a diagnosis of falciparum malaria hospitalized at 4 tertiary referral hospitals in Myanmar had blood cultures collected at admission. The frequency of concomitant bacteremia and the clinical characteristics of the patients, with and without bacteremia, were explored. Results.  Of 67 adults hospitalized with falciparum malaria, 9 (13% [95% confidence interval, 5.3%-21.6%]) were also bacteremic on admission, 7 (78%) with Gram-negative enteric organisms (Escherichia coli [n = 3], typhoidal Salmonella species [n = 3], nontyphoidal Salmonella [n = 1]). Bacteremic adults had more severe disease (median Respiratory Coma Acidosis Malaria [RCAM] score 3; interquartile range [IQR], 1-4) than those without bacteremia (median RCAM score 1; IQR, 1-2) and had a higher frequency of acute kidney injury (50% vs 16%, P = .03). Although 35 (52%) were at high risk of death (RCAM score ≥2), all 67 patients in the study survived, 51 (76%) of whom received empirical antibiotics on admission. Conclusions.  Bacteremia was relatively frequent in adults hospitalized with falciparum malaria in Myanmar. Like children in high transmission settings, bacteremic adults in this low transmission setting were sicker than nonbacteremic adults, and were often difficult to identify at presentation. Empirical antibiotics may also be appropriate in adults hospitalized with falciparum malaria in low transmission settings, until bacterial infection is excluded.

  17. Falciparum malaria as an emerging cause of fever in adults living in Gabon, Central Africa.

    PubMed

    Bouyou-Akotet, Marielle K; Offouga, Christelle L; Mawili-Mboumba, Denise P; Essola, Laurence; Madoungou, Blondel; Kombila, Maryvonne

    2014-01-01

    Following the observed increase of malaria prevalence among older children in Gabon, a descriptive observational study was carried out in 2012 to determine the prevalence of malaria in adults presenting with fever in two health centres of Libreville, the capital city of Gabon. Thick- and thin-blood smears for malaria diagnosis were performed in febrile individuals aged more than 15 years old. Age, use of bed nets, previous antimalarial drug treatment, clinical symptoms, chest radiography results, and available haemoglobin data were also recorded. Among the 304 patients screened, the global malaria frequency was of 42.1% (n = 128/34). Plasmodium (P). falciparum was the only species identified. The proportion of patients with a clinical malaria requiring parenteral treatment was 38.5%, whereas 47.5% of outpatients had uncomplicated malaria. According to WHO classification, 14 (19.7%) infected patients had severe malaria; neurological and respiratory symptoms tended to be more frequent in case of P. falciparum infection. Anaemia was found in 51.5% adults and none had severe anaemia. Almost half of adults consulting for fever in two health centres of the urban city of Libreville have malaria. The use of insecticide-treated bed nets, the screening, and the treatment of individuals with P. falciparum microscopic and submicroscopic asymptomatic infection or clinical malaria should be emphasized to reduce the transmission.

  18. Population pharmacokinetics of mefloquine, administered as a fixed-dose combination of artesunate-mefloquine in Indian patients for the treatment of acute uncomplicated Plasmodium falciparum malaria

    PubMed Central

    2014-01-01

    Background Fixed-dose combinations of artemisinin combination therapy are strongly recommended to facilitate drug administration and compliance. New fixed-dose combinations must nevertheless be evaluated in relevant populations in terms of efficacy and pharmacokinetics. Methods A single-arm, open-label, clinical trial was performed in Indian patients with acute uncomplicated Plasmodium falciparum malaria to investigate the efficacy and the pharmacokinetics of mefloquine when combined with artesunate in a fixed-dose combination (400/200 mg of mefloquine base/artesunate). The pharmacokinetic analysis was performed using a population approach. Results Seventy-seven patients were included in the study. Mefloquine pharmacokinetics obeys a two-compartment model with first-order absorption and elimination. Mean parameter estimates (% inter-individual variability) were as follows: 0.16 h-1 (75%) for the absorption rate constant, 1.13 L/h (30%) for the apparent plasma clearance, 271 L (21%) for the apparent central distribution volume, 344 L (54%) for the apparent peripheral distribution volume, and 1.43 L/h for the apparent distribution clearance. These values were consistent with the pharmacokinetic results described in Thai patients. No significant covariate was found for clearance. Body weight explained the inter-individual variability of the apparent central and peripheral distribution volumes. The PCR-adjusted efficacy of the treatment was 100%. Conclusions The lack of significant covariate explaining the inter-individual variability of mefloquine clearance, combined with the excellent efficacy, supports the use of the standard 200/400 mg of artesunate-mefloquine fixed-dose combination in Indian patients with uncomplicated P. falciparum malaria. Trial Registration Clinical Trial Registration: ISRCTN70618692 PMID:24886117

  19. Amodiaquine failure associated with erythrocytic glutathione in Plasmodium falciparum malaria

    PubMed Central

    Zuluaga, Lina; Pabón, Adriana; López, Carlos; Ochoa, Aleida; Blair, Silvia

    2007-01-01

    Objective To establish the relationship between production of glutathione and the therapeutic response to amodiaquine (AQ) monotherapy in Plasmodium falciparum non-complicated malaria patients. Methodology Therapeutic response to AQ was evaluated in 32 patients with falciparum malaria in two townships of Antioquia, Colombia, and followed-up for 28 days. For every patient, total glutathione and enzymatic activity (glutathione reductase, GR, and γ-glutamylcysteine synthetase, γ-GCS) were determined in parasitized erythrocytes, non-infected erythrocytes and free parasites, on the starting day (day zero, before ingestion of AQ) and on the day of failure (in case of occurrence). Results There was found an AQ failure of 31.25%. Independent of the therapeutic response, on the starting day and on the day of failure, lower total glutathione concentration and higher GR activities in parasitized erythrocytes were found, compared with non-infected erythrocytes (p < 0.003). In addition, only on the day of failure, γ-GCS activity of parasitized erythrocytes was higher, compared with that of healthy erythrocytes (p = 0.01). Parasitized and non-parasitized erythrocytes in therapeutic failure patients (TF) had higher total glutathione on the starting day compared with those of adequate clinical response (ACR) (p < 0.02). Parasitized erythrocytes of TF patients showed lower total glutathione on the failure day, compared with starting day (p = 0.017). No differences was seen in the GR and γ-GCS activities by compartment, neither between the two therapeutic response groups nor between the two treatment days. Conclusion This study is a first approach to explaining P. falciparum therapeutic failure in humans through differences in glutathione metabolism in TF and ACR patients. These results suggest a role for glutathione in the therapeutic failure to antimalarials. PMID:17451604

  20. SD Bioline malaria antigen Pf (HRP-2/pLHD) for assessing efficacy of artemisinin combination therapy against Plasmodium falciparum in pediatric patients in the Democratic Republic of the Congo

    PubMed Central

    Kilauzi, Albert Lukuka; Mulumba, Jose Gaby Tshikuka; Magafu, Mgaywa Gilbert Mjungu Damas; Matchaba-Hove, Reginald; Tapera, Roy; Magafu, Naoko Shimizu; Tamfum, Jean Jacques Muyembe

    2015-01-01

    Introduction The emergence of Plasmodium falciparum resistance to artemisinin combination therapy (ACT) is a worrying development. It calls for close surveillance to monitor the efficacy of the drugs. The objectives of this study were to determine the performance of SD Bioline malaria AgPf(HRP-2/pLDH) 3 band Rapid Diagnostic Test (RDT) against Giemsa-stained blood smear and evaluate the suitability of this test in assessing the therapeutic efficacy of ACT in pediatric malaria patients in the Democratic Republic of the Congo (DRC). Methods Five hundred and one patients with malaria symptoms were screened for P. falciparum in Kinshasa, DRC. Of the 166 patients who tested positive for P. falciparum at recruitment (day 0), 103 consented to participate in this study and were followed up and retested for P. falciparum on day 3, day 7, day 14, day 21 and day 28. Results Sensitivity and specificity of the test were significantly high on day 0 and so were their positive and negative predictive values. Higher proportions of false positive cases were observed on the HRP-2 band irrespective of patient parasite densities during the follow up but these were barely seen on the pLDH band. Some patients turned positive during follow up but pLDH readings remained consistent with blood smear readings. Conclusion SD Bioline malaria AgPf(HRP-2/pLDH) RDT demonstrated high performance in DRC. Thus, the test can be employed to assess the efficacy of ACT in pediatric malaria patients and prioritize areas that require the deployment of advanced testing like polymerase chain reaction (PCR). PMID:26966500

  1. How Reliable Are Hematological Parameters in Predicting Uncomplicated Plasmodium falciparum Malaria in an Endemic Region?

    PubMed Central

    Muwonge, Haruna; Kikomeko, Sharif; Sembajjwe, Larry Fred; Seguya, Abdul; Namugwanya, Christine

    2014-01-01

    Background Malaria remains endemic in Sub-Saharan Africa. Hematological changes that occur have been suggested as potential predictors of malaria. This study was aimed at evaluating the diagnostic relevance of hematological parameters in predicting malaria. Methods A cross-sectional study involving 370 patients with signs and symptoms of malaria was conducted at Mulago Hospital, Kampala, from May, 2012 to February, 2013. Thin and thick blood films were prepared for each patient and stained with Giemsa to aid the detection of malaria parasites. Patients’ hematological parameters were determined. Results Out of the 370 patients, 61 (16.5%) had malaria. Significant differences in the hematological parameters between P. falciparum malaria parasitemic patients and nonparasitemic patients were only observed in mean (±SD) of the differential monocyte count (10.89 ± 6.23% versus 8.98 ± 5.02%, p = 0.01) and the platelet count (172.43 (± 80.41) ×103 cells/μl versus 217.82 ± (95.96) ×103 cells/μl p = 0.00). The mean (±SD) values of the red blood cell indices (hemoglobin count, MCV, MCH, and MCHC), the differential neutrophil and lymphocyte counts, and the mean platelet volume (MPV) did not significantly differ between the two groups. Conclusion Hematological changes are unreliable laboratory indicators of malaria in acute uncomplicated Plasmodium falciparum malaria. PMID:25285308

  2. Urinary bile casts in bile cast nephropathy secondary to severe falciparum malaria

    PubMed Central

    Mohapatra, Manoj Kumar; Behera, Ashok Kumar; Karua, Purna Chandra; Bariha, Prafulla Kumar; Rath, Ashutosh; Aggrawal, Kailash Chandra; Nahak, Snigdha Rani; Gudaganatti, Santosh Shankar

    2016-01-01

    Background Severe cholestatic jaundice may complicate with bile cast nephropathy (BCN) causing severe acute kidney injury (AKI). In this study, we investigate BCN in severe falciparum malaria complicated with jaundice and AKI. Methods This prospective study was conducted in a tertiary health care institution with high prevalence of malaria. A cohort of 110 patients with falciparum malaria complicated with cerebral malaria, jaundice and AKI were enrolled. Species diagnosis was made from peripheral blood smear or rapid diagnostic test. Severe malaria was diagnosed from WHO criteria. BCN was diagnosed with the detection of bile casts in urine or in biopsy. The recovery pattern and outcome with and without BCN was assessed. Results Out of 110 patients, 20 (18.2%) patients had BCN and 15 (13.6%) patients had hepato-renal syndrome. Patients with BCN had high conjugated bilirubin (26.5 ± 4.1 mg/dL), urea (75.9 ± 10.3 mg/dL) and creatinine (7.2 ± 0.8 mg/dL), longer duration of illness (6.4 ± 1.1 days), higher mortality (25.0%) and prolonged recovery time of hepatic (9.6 ± 2.4 days) and renal dysfunction (15.1 ± 6.5 days) compared with patients without BCN. Conclusions Prolonged duration of illness and increased bilirubin cause BCN among patients with severe falciparum malaria with jaundice and AKI, which is associated with high mortality and morbidity. PMID:27478612

  3. 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

  4. Fatal Plasmodium falciparum Malaria Causes Specific Patterns of Splenic Architectural Disorganization

    PubMed Central

    Urban, Britta C.; Hien, Tran T.; Day, Nicholas P.; Phu, Nguyen H.; Roberts, Rachel; Pongponratn, Emsri; Jones, Margret; Mai, Nguyen T. H.; Bethell, Delia; Turner, Gareth D. H.; Ferguson, David; White, Nicholas J.; Roberts, David J.

    2005-01-01

    The spleen is critical for host defense against pathogens, including Plasmodium falciparum. It has a dual role, not only removing aged or antigenically altered erythrocytes from the blood but also as the major lymphoid organ for blood-borne or systemic infections. The human malaria parasite P. falciparum replicates within erythrocytes during asexual blood stages and causes repeated infections that can be associated with severe disease. In spite of the crucial role of the spleen in the innate and acquired immune response to malaria, there is little information on the pathology of the spleen in human malaria. We performed a histological and quantitative immunohistochemical study of spleen sections from Vietnamese adults dying from severe falciparum malaria and compared the findings with the findings for spleen sections from control patients and patients dying from systemic bacterial sepsis. Here we report that the white pulp in the spleens of patients dying from malaria showed a marked architectural disorganization. We observed a marked dissolution of the marginal zones with relative loss of B cells. Furthermore, we found strong HLA-DR expression on sinusoidal lining cells but downregulation on cordal macrophages. P. falciparum infection results in alterations in splenic leukocytes, many of which are not seen in sepsis. PMID:15784539

  5. [Imported falciparum malaria situation in Henan Province during 2005-2009].

    PubMed

    Zhang, Hong-Wei; Su, Yun-Pu; Zhao, Xu-Dong; Yan, Qiu-Ye; Liu, Ying; Chen, Jian-She

    2010-12-30

    Imported falciparum malaria data of Henan Province in 2005-2009 were collected and statistically analyzed by using Microsoft Office Excel 2003. A total of 84 imported falciparum malaria cases with one death were reported during 2005-2009. The ratio of males to females was 20 : 1(80/4). The average age was (34 +/- 11) years old. Seventy-five patients returned from Africa, occupying 89.3%. The number of annual cases reported in 2008 (24 cases) and 2009 (32 cases) was higher than that in 2005-2007(9-10 cases). The top three high-risk populations were farmers (34 cases), workers (17 cases) and the cadre (13 cases), accounted for 76.2% of all cases. The cases were reported every month, of which 37 cases (44.0%) were reported in June and July. All cases had a history of prior residence in falciparum malaria endemic area, and the initial symptom was fever. The average interval from symptom appearing to diagnosis was (5.9 +/- 8.6) d, only 21.4% (18/84) of the patients was diagnosed within 24h. There were 72 laboratory-confirmed cases (85.7%). Seventeen cases (22.1%) were reported by county level medical treatment units. A total of 83 cases recovered with the treatment of artemisinin-based combination drugs. One case died with serious cerebral malaria. Effective measures should be carried to control the increasing trend of imported falciparum malaria.

  6. High Frequency of Clinically Significant Bacteremia in Adults Hospitalized With Falciparum Malaria.

    PubMed

    Nyein, Phyo Pyae; Aung, Ne Myo; Kyi, Tint Tint; Htet, Zaw Win; Anstey, Nicholas M; Kyi, Mar Mar; Hanson, Josh

    2016-01-01

    Background.  African children with severe falciparum malaria commonly have concomitant Gram-negative bacteremia, but co-infection has been thought to be relatively rare in adult malaria. Methods.  Adults with a diagnosis of falciparum malaria hospitalized at 4 tertiary referral hospitals in Myanmar had blood cultures collected at admission. The frequency of concomitant bacteremia and the clinical characteristics of the patients, with and without bacteremia, were explored. Results.  Of 67 adults hospitalized with falciparum malaria, 9 (13% [95% confidence interval, 5.3%-21.6%]) were also bacteremic on admission, 7 (78%) with Gram-negative enteric organisms (Escherichia coli [n = 3], typhoidal Salmonella species [n = 3], nontyphoidal Salmonella [n = 1]). Bacteremic adults had more severe disease (median Respiratory Coma Acidosis Malaria [RCAM] score 3; interquartile range [IQR], 1-4) than those without bacteremia (median RCAM score 1; IQR, 1-2) and had a higher frequency of acute kidney injury (50% vs 16%, P = .03). Although 35 (52%) were at high risk of death (RCAM score ≥2), all 67 patients in the study survived, 51 (76%) of whom received empirical antibiotics on admission. Conclusions.  Bacteremia was relatively frequent in adults hospitalized with falciparum malaria in Myanmar. Like children in high transmission settings, bacteremic adults in this low transmission setting were sicker than nonbacteremic adults, and were often difficult to identify at presentation. Empirical antibiotics may also be appropriate in adults hospitalized with falciparum malaria in low transmission settings, until bacterial infection is excluded. PMID:26989752

  7. High Frequency of Clinically Significant Bacteremia in Adults Hospitalized With Falciparum Malaria

    PubMed Central

    Nyein, Phyo Pyae; Aung, Ne Myo; Kyi, Tint Tint; Htet, Zaw Win; Anstey, Nicholas M.; Kyi, Mar Mar; Hanson, Josh

    2016-01-01

    Background. African children with severe falciparum malaria commonly have concomitant Gram-negative bacteremia, but co-infection has been thought to be relatively rare in adult malaria. Methods. Adults with a diagnosis of falciparum malaria hospitalized at 4 tertiary referral hospitals in Myanmar had blood cultures collected at admission. The frequency of concomitant bacteremia and the clinical characteristics of the patients, with and without bacteremia, were explored. Results. Of 67 adults hospitalized with falciparum malaria, 9 (13% [95% confidence interval, 5.3%–21.6%]) were also bacteremic on admission, 7 (78%) with Gram-negative enteric organisms (Escherichia coli [n = 3], typhoidal Salmonella species [n = 3], nontyphoidal Salmonella [n = 1]). Bacteremic adults had more severe disease (median Respiratory Coma Acidosis Malaria [RCAM] score 3; interquartile range [IQR], 1–4) than those without bacteremia (median RCAM score 1; IQR, 1–2) and had a higher frequency of acute kidney injury (50% vs 16%, P = .03). Although 35 (52%) were at high risk of death (RCAM score ≥2), all 67 patients in the study survived, 51 (76%) of whom received empirical antibiotics on admission. Conclusions. Bacteremia was relatively frequent in adults hospitalized with falciparum malaria in Myanmar. Like children in high transmission settings, bacteremic adults in this low transmission setting were sicker than nonbacteremic adults, and were often difficult to identify at presentation. Empirical antibiotics may also be appropriate in adults hospitalized with falciparum malaria in low transmission settings, until bacterial infection is excluded. PMID:26989752

  8. Monocyte polarization in children with falciparum malaria: relationship to nitric oxide insufficiency and disease severity.

    PubMed

    Weinberg, J Brice; Volkheimer, Alicia D; Rubach, Matthew P; Florence, Salvatore M; Mukemba, Jackson P; Kalingonji, Ayam R; Langelier, Charles; Chen, Youwei; Bush, Margaret; Yeo, Tsin W; Granger, Donald L; Anstey, Nicholas M; Mwaikambo, Esther D

    2016-01-01

    We earlier established that nitric oxide (NO) is protective against severe malaria and that arginine and NO levels are reduced in malaria patients. We now show that an M2-like blood monocyte phenotype is significantly associated with hypoargininemia, NO insufficiency, and disease severity in Tanzanian children with falciparum malaria. Compared to control children (n = 106), children with moderately severe (n = 77) and severe falciparum malaria (n = 129) had significantly higher mononuclear cell arginase 1 mRNA, protein, and enzyme activity; lower NOS2 mRNA; lower plasma arginine; and higher plasma IL-10, IL-13, and IL-4. In addition, monocyte CD206 and CD163 and plasma soluble CD163 were elevated. Multivariate logistic regression analysis revealed a significant correlation of risk of severe malaria with both plasma IL-10 and soluble CD163 levels. Monocyte M2 skewing likely contributes to NO bioinsufficiency in falciparum malaria in children. Treatments that reverse the M2 polarization may have potential as adjunctive treatment for malaria. PMID:27385484

  9. Monocyte polarization in children with falciparum malaria: relationship to nitric oxide insufficiency and disease severity.

    PubMed

    Weinberg, J Brice; Volkheimer, Alicia D; Rubach, Matthew P; Florence, Salvatore M; Mukemba, Jackson P; Kalingonji, Ayam R; Langelier, Charles; Chen, Youwei; Bush, Margaret; Yeo, Tsin W; Granger, Donald L; Anstey, Nicholas M; Mwaikambo, Esther D

    2016-01-01

    We earlier established that nitric oxide (NO) is protective against severe malaria and that arginine and NO levels are reduced in malaria patients. We now show that an M2-like blood monocyte phenotype is significantly associated with hypoargininemia, NO insufficiency, and disease severity in Tanzanian children with falciparum malaria. Compared to control children (n = 106), children with moderately severe (n = 77) and severe falciparum malaria (n = 129) had significantly higher mononuclear cell arginase 1 mRNA, protein, and enzyme activity; lower NOS2 mRNA; lower plasma arginine; and higher plasma IL-10, IL-13, and IL-4. In addition, monocyte CD206 and CD163 and plasma soluble CD163 were elevated. Multivariate logistic regression analysis revealed a significant correlation of risk of severe malaria with both plasma IL-10 and soluble CD163 levels. Monocyte M2 skewing likely contributes to NO bioinsufficiency in falciparum malaria in children. Treatments that reverse the M2 polarization may have potential as adjunctive treatment for malaria.

  10. Monocyte polarization in children with falciparum malaria: relationship to nitric oxide insufficiency and disease severity

    PubMed Central

    Weinberg, J. Brice; Volkheimer, Alicia D.; Rubach, Matthew P.; Florence, Salvatore M.; Mukemba, Jackson P.; Kalingonji, Ayam R.; Langelier, Charles; Chen, Youwei; Bush, Margaret; Yeo, Tsin W.; Granger, Donald L.; Anstey, Nicholas M.; Mwaikambo, Esther D.

    2016-01-01

    We earlier established that nitric oxide (NO) is protective against severe malaria and that arginine and NO levels are reduced in malaria patients. We now show that an M2-like blood monocyte phenotype is significantly associated with hypoargininemia, NO insufficiency, and disease severity in Tanzanian children with falciparum malaria. Compared to control children (n = 106), children with moderately severe (n = 77) and severe falciparum malaria (n = 129) had significantly higher mononuclear cell arginase 1 mRNA, protein, and enzyme activity; lower NOS2 mRNA; lower plasma arginine; and higher plasma IL-10, IL-13, and IL-4. In addition, monocyte CD206 and CD163 and plasma soluble CD163 were elevated. Multivariate logistic regression analysis revealed a significant correlation of risk of severe malaria with both plasma IL-10 and soluble CD163 levels. Monocyte M2 skewing likely contributes to NO bioinsufficiency in falciparum malaria in children. Treatments that reverse the M2 polarization may have potential as adjunctive treatment for malaria. PMID:27385484

  11. Hemoglobinopathies: Slicing the Gordian Knot of Plasmodium falciparum Malaria Pathogenesis

    PubMed Central

    Taylor, Steve M.; Cerami, Carla; Fairhurst, Rick M.

    2013-01-01

    Plasmodium falciparum malaria kills over 500,000 children every year and has been a scourge of humans for millennia. Owing to the co-evolution of humans and P. falciparum parasites, the human genome is imprinted with polymorphisms that not only confer innate resistance to falciparum malaria, but also cause hemoglobinopathies. These genetic traits—including hemoglobin S (HbS), hemoglobin C (HbC), and α-thalassemia—are the most common monogenic human disorders and can confer remarkable degrees of protection from severe, life-threatening falciparum malaria in African children: the risk is reduced 70% by homozygous HbC and 90% by heterozygous HbS (sickle-cell trait). Importantly, this protection is principally present for severe disease and largely absent for P. falciparum infection, suggesting that these hemoglobinopathies specifically neutralize the parasite's in vivo mechanisms of pathogenesis. These hemoglobin variants thus represent a “natural experiment” to identify the cellular and molecular mechanisms by which P. falciparum produces clinical morbidity, which remain partially obscured due to the complexity of interactions between this parasite and its human host. Multiple lines of evidence support a restriction of parasite growth by various hemoglobinopathies, and recent data suggest this phenomenon may result from host microRNA interference with parasite metabolism. Multiple hemoglobinopathies mitigate the pathogenic potential of parasites by interfering with the export of P. falciparum erythrocyte membrane protein 1 (PfEMP1) to the surface of the host red blood cell. Few studies have investigated their effects upon the activation of the innate and adaptive immune systems, although recent murine studies suggest a role for heme oxygenase-1 in protection. Ultimately, the identification of mechanisms of protection and pathogenesis can inform future therapeutics and preventive measures. Hemoglobinopathies slice the “Gordian knot” of host and parasite

  12. An outbreak of Plasmodium falciparum malaria in the Torres Strait.

    PubMed

    Preston-Thomas, Annie; Gair, Richard W; Hosking, Kelly A; Devine, Gregor J; Donohue, Steven D

    2012-06-01

    This report describes the largest outbreak of Plasmodium falciparum malaria in the Torres Strait for more than 25 years. It details factors that may have contributed to the outbreak, the public health response and implications for the broader region. Eight cases of locally-acquired falciparum malaria occurred on Saibai and Dauan islands during March and April 2011. Including imports, there were 17 P. falciparum notifications between February and May 2011. Three cases of pure P. vivax malaria that might have been locally acquired have been omitted from this report. Malaria is endemic on the nearby coast of Papua New Guinea (PNG), and regularly imported to the Torres Strait where a competent vector exists in sufficient numbers to transmit the disease to the local population. The most common malaria vectors in northern Australia and Torres Strait are the Anopheles farauti complex. Factors contributing to the outbreak may include an increase in travel between the outer islands and PNG, inadequate local vector control and late or missed diagnoses of malaria. Outbreak management involved intensive case finding and treatment, vector control and health promotion. Reducing the risk of future outbreaks requires studies of vector behaviour, ecology and management, health promotion, improvements to protective infrastructure, and clinical guideline revision. Further malaria outbreaks are likely in the Torres Strait and elsewhere in northern Australia. It is important to maintain awareness and be prepared to respond rapidly. PMID:23186217

  13. Polysome profiling of the malaria parasite Plasmodium falciparum.

    PubMed

    Lacsina, Joshua R; LaMonte, Gregory; Nicchitta, Christopher V; Chi, Jen-Tsan

    2011-09-01

    In the malaria parasite Plasmodium falciparum, global studies of translational regulation have been hampered by the inability to isolate malaria polysomes. We describe here a novel method for polysome profiling in P. falciparum, a powerful approach which allows both a global view of translation and the measurement of ribosomal loading and density for specific mRNAs. Simultaneous lysis of infected erythrocytes and parasites releases stable, intact malaria polysomes, which are then purified by centrifugation through a sucrose cushion. The polysomes are resuspended, separated by velocity sedimentation and then fractionated, yielding a characteristic polysome profile reflecting the global level of translational activity in the parasite. RNA isolated from specific fractions can be used to determine the density of ribosomes loaded onto a particular transcript of interest, and is free of host ribosome contamination. Thus, our approach opens translational regulation in malaria to genome-wide analysis.

  14. Serum protein concentrations in Plasmodium falciparum malaria.

    PubMed

    Graninger, W; Thalhammer, F; Hollenstein, U; Zotter, G M; Kremsner, P G

    1992-12-01

    In patients with uncomplicated Plasmodium falciparum infection cytokine-mediated serum protein levels of C-reactive protein (CRP), coeruloplasmin (COE), beta 2-microglobulin (B2M), alpha 1-acid glycoprotein (AAG), alpha 1-antitrypsin (AAT), haptoglobin (HPT), prealbumin (PRE), retinol binding protein (RBP), albumin (ALB) and transferrin (TRF) were measured in an endemic area of the Amazonian rain forest. Semi-immune (SI) and nonimmune (NI) patients were investigated. In both patient groups the serum concentrations of CRP, COE and B2M were elevated on admission. In addition AAG and AAT concentrations were increased in NI patients compared to control subjects. Significantly lower serum concentrations of HPT, PRE, RBP, ALB and TRF were seen in both patient groups during the acute phase of the disease, and were more pronounced in NI patients. After a 28-day follow-up, AAT and B2M were normal in SI patients but HPT, AAT and B2M were still significantly altered in NI patients.

  15. Delayed parasite clearance after treatment with dihydroartemisinin-piperaquine in Plasmodium falciparum malaria patients in central Vietnam.

    PubMed

    Thriemer, Kamala; Hong, Nguyen Van; Rosanas-Urgell, Anna; Phuc, Bui Quang; Ha, Do Manh; Pockele, Evi; Guetens, Pieter; Van, Nguyen Van; Duong, Tran Thanh; Amambua-Ngwa, Alfred; D'Alessandro, Umberto; Erhart, Annette

    2014-12-01

    Reduced susceptibility of Plasmodium falciparum toward artemisinin derivatives has been reported from the Thai-Cambodian and Thai-Myanmar borders. Following increasing reports from central Vietnam of delayed parasite clearance after treatment with dihydroartemisinin-piperaquine (DHA-PPQ), the current first-line treatment, we carried out a study on the efficacy of this treatment. Between September 2012 and February 2013, we conducted a 42-day in vivo and in vitro efficacy study in Quang Nam Province. Treatment was directly observed, and blood samples were collected twice daily until parasite clearance. In addition, genotyping, quantitative PCR (qPCR), and in vitro sensitivity testing of isolates was performed. The primary endpoints were parasite clearance rate and time. The secondary endpoints included PCR-corrected and uncorrected cure rates, qPCR clearance profiles, in vitro sensitivity results (for chloroquine, dihydroartemisinin, and piperaquine), and genotyping for mutations in the Kelch 13 propeller domain. Out of 672 screened patients, 95 were recruited and 89 available for primary endpoint analyses. The median parasite clearance time (PCT) was 61.7 h (interquartile range [IQR], 47.6 to 83.2 h), and the median parasite clearance rate had a slope half-life of 6.2 h (IQR, 4.4 to 7.5 h). The PCR-corrected efficacy rates were estimated at 100% at day 28 and 97.7% (95% confidence interval, 91.2% to 99.4%) at day 42. At day 3, the P. falciparum prevalence by qPCR was 2.5 times higher than that by microscopy. The 50% inhibitory concentrations (IC50s) of isolates with delayed clearance times (≥ 72 h) were significantly higher than those with normal clearance times for all three drugs. Delayed parasite clearance (PCT, ≥ 72 h) was significantly higher among day 0 samples carrying the 543 mutant allele (47.8%) than those carrying the wild-type allele (1.8%; P = 0.048). In central Vietnam, the efficacy of DHA-PPQ is still satisfactory, but the parasite clearance time

  16. Adjunctive therapy for cerebral malaria and other severe forms of Plasmodium falciparum malaria

    PubMed Central

    John, Chandy C; Kutamba, Elizabeth; Mugarura, Keith; Opoka, Robert O

    2010-01-01

    Severe malaria due to Plasmodium falciparum causes more than 800,000 deaths every year. Primary therapy with quinine or artesunate is generally effective in controlling P. falciparum parasitemia, but mortality from cerebral malaria and other forms of severe malaria remains unacceptably high. Long-term cognitive impairment is also common in children with cerebral malaria. Of the numerous adjunctive therapies for cerebral malaria and severe malaria studied over the past five decades, only one (albumin) was associated with a reduction in mortality. In this article, we review past and ongoing studies of adjunctive therapy, and examine the evidence of efficacy for newer therapies, including inhibitors of cytoadherence (e.g., levamisole), immune modulators (e.g., rosiglitazone), agents that increase nitric oxide levels (e.g., arginine) and neuroprotective agents (e.g., erythropoietin). PMID:20818944

  17. [Imported severe falciparum malaria in France in 2000-2011: epidemiological trends and the need for new treatments].

    PubMed

    Danis, Martin; Thellier, Marc; Jauréguiberry, Stéphane; Bricaire, François; Buffet, Pierre

    2013-03-01

    In France malaria is monitored by the Centre National de Référence (CNR) du Paludisme (French National Malaria Reference Centre). The annual incidence of imported malaria currently ranges from 4 800 to 3 500 cases and has fallen gradually since 2000. However, the proportion of patients with severe P. falciparum malaria is increasing (2.5% in 2000, 7% in 2011), particularly among French residents from sub-Saharan Africa who neglect preventive measures. Overall mortality remains stable at 0.4%, but survival is improving in severe cases. The survival rate is higher among patients of African origin than among Europeans. Nonetheless, between 10 and 20 patients die of malaria every year in France. Two large controlled trials published in 2005 and 2010 showed that IV artesunate, a new treatment for severe falciparum malaria, is associated with a 22-38% absolute reduction in mortality relative to quinine. Artesunate is not licensed in Europe but has been available in France since May 2011 through a named-patient program controlled by the French Agency for Drug Safety [ANSM]. The first 99 patients treated with artesunate up to September 2012 experienced satisfactory efficacy and tolerability. Delayed, sometimes persistent anemia was observed in 13 patients, a rate similar to that noted in recent reports on imported malaria in Europe. This unexpected adverse effect requires further investigation. IV artesunate is now recommended as the first-line treatment for severe falciparum malaria in France.

  18. Blood coagulation in falciparum malaria--a review.

    PubMed

    Ghosh, Kanjaksha; Shetty, Shrimati

    2008-03-01

    Falciparum malaria infection influences blood coagulation by various interacting pathobiological mechanisms, the most important being the overwhelming response of the host to sepsis resulting in a cytokine storm. In addition, the parasite infects the red cells leading to changes in the red cell phospholipid composition which supports blood coagulation. Red cells infected with Plasmodium falciparum also adhere to deeper tissue capillary endothelium leading to profound damage to endothelial cells leading to further activation. This results in widespread consumption of platelets and activation of blood coagulation which at times culminates in a clinically and pathologically detectable disseminated intravascular coagulation (DIC). Monocyte-macrophage system also gets activated in this infection compounding the hypercoagulable state. Heavy parasitaemia leading to occlusion of hepatic microcirculation leads to abnormalities in synthesis and secretion of coagulation factors and their inhibitors. Drugs used in the treatment for falciparum malaria can cause thrombocytopaenia, bone marrow suppression and haemolytic anaemia, all of which can interfere indirectly with blood coagulation. Microparticle formation from platelets, red cells and macrophages also causes widespread activation of blood coagulation, and this recently observed mechanism is the focus of intense research in many other inflammatory and neoplastic conditions where there is activation of blood coagulation system. Thus, in severe falciparum malaria, there is activation of blood coagulation system along with thrombocytopaenia, even before widespread DIC and coagulation failure occur.

  19. [From malaria parasite point of view--Plasmodium falciparum evolution].

    PubMed

    Zerka, Agata; Kaczmarek, Radosław; Jaśkiewicz, Ewa

    2015-12-31

    Malaria is caused by infection with protozoan parasites belonging to the genus Plasmodium, which have arguably exerted the greatest selection pressure on humans in the history of our species. Besides humans, different Plasmodium parasites infect a wide range of animal hosts, from marine invertebrates to primates. On the other hand, individual Plasmodium species show high host specificity. The extraordinary evolution of Plasmodium probably began when a free-living red algae turned parasitic, and culminated with its ability to thrive inside a human red blood cell. Studies on the African apes generated new data on the evolution of malaria parasites in general and the deadliest human-specific species, Plasmodium falciparum, in particular. Initially, it was hypothesized that P. falciparum descended from the chimpanzee malaria parasite P. reichenowi, after the human and the chimp lineage diverged about 6 million years ago. However, a recently identified new species infecting gorillas, unexpectedly showed similarity to P. falciparum and was therefore named P. praefalciparum. That finding spurred an alternative hypothesis, which proposes that P. falciparum descended from its gorilla rather than chimp counterpart. In addition, the gorilla-to-human host shift may have occurred more recently (about 10 thousand years ago) than the theoretical P. falciparum-P. reichenowi split. One of the key aims of the studies on Plasmodium evolution is to elucidate the mechanisms that allow the incessant host shifting and retaining the host specificity, especially in the case of human-specific species. Thorough understanding of these phenomena will be necessary to design effective malaria treatment and prevention strategies.

  20. Dihydroartemisinin-piperaquine for treating uncomplicated Plasmodium falciparum malaria

    PubMed Central

    Zani, Babalwa; Gathu, Michael; Donegan, Sarah; Olliaro, Piero L; Sinclair, David

    2014-01-01

    Background The World Health Organization (WHO) recommends Artemisinin-based Combination Therapy (ACT) for treating uncomplicated Plasmodium falciparum malaria. This review aims to assist the decision-making of malaria control programmes by providing an overview of the relative effects of dihydroartemisinin-piperaquine (DHA-P) versus other recommended ACTs. Objectives To evaluate the effectiveness and safety of DHA-P compared to other ACTs for treating uncomplicated P. falciparum malaria in adults and children. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL) published in The Cochrane Library; MEDLINE; EMBASE; LILACS, and the metaRegister of Controlled Trials (mRCT) up to July 2013. Selection criteria Randomized controlled trials comparing a three-day course of DHA-P to a three-day course of an alternative WHO recommended ACT in uncomplicated P. falciparum malaria. Data collection and analysis Two authors independently assessed trials for eligibility and risk of bias, and extracted data. We analysed primary outcomes in line with the WHO 'Protocol for assessing and monitoring antimalarial drug efficacy’ and compared drugs using risk ratios (RR) and 95% confidence intervals (CI). Secondary outcomes were effects on gametocytes, haemoglobin, and adverse events. We assessed the quality of evidence using the GRADE approach. Main results We included 27 trials, enrolling 16,382 adults and children, and conducted between 2002 and 2010. Most trials excluded infants aged less than six months and pregnant women. DHA-P versus artemether-lumefantrine In Africa, over 28 days follow-up, DHA-P is superior to artemether-lumefantrine at preventing further parasitaemia (PCR-unadjusted treatment failure: RR 0.34, 95% CI 0.30 to 0.39, nine trials, 6200 participants, high quality evidence), and although PCR-adjusted treatment failure was below 5% for both ACTs, it was consistently lower

  1. A new world malaria map: Plasmodium falciparum endemicity in 2010

    PubMed Central

    2011-01-01

    Background Transmission intensity affects almost all aspects of malaria epidemiology and the impact of malaria on human populations. Maps of transmission intensity are necessary to identify populations at different levels of risk and to evaluate objectively options for disease control. To remain relevant operationally, such maps must be updated frequently. Following the first global effort to map Plasmodium falciparum malaria endemicity in 2007, this paper describes the generation of a new world map for the year 2010. This analysis is extended to provide the first global estimates of two other metrics of transmission intensity for P. falciparum that underpin contemporary questions in malaria control: the entomological inoculation rate (PfEIR) and the basic reproductive number (PfR). Methods Annual parasite incidence data for 13,449 administrative units in 43 endemic countries were sourced to define the spatial limits of P. falciparum transmission in 2010 and 22,212 P. falciparum parasite rate (PfPR) surveys were used in a model-based geostatistical (MBG) prediction to create a continuous contemporary surface of malaria endemicity within these limits. A suite of transmission models were developed that link PfPR to PfEIR and PfR and these were fitted to field data. These models were combined with the PfPR map to create new global predictions of PfEIR and PfR. All output maps included measured uncertainty. Results An estimated 1.13 and 1.44 billion people worldwide were at risk of unstable and stable P. falciparum malaria, respectively. The majority of the endemic world was predicted with a median PfEIR of less than one and a median PfRc of less than two. Values of either metric exceeding 10 were almost exclusive to Africa. The uncertainty described in both PfEIR and PfR was substantial in regions of intense transmission. Conclusions The year 2010 has a particular significance as an evaluation milestone for malaria global health policy. The maps presented here

  2. Malaria vaccines: identifying Plasmodium falciparum liver-stage targets.

    PubMed

    Longley, Rhea J; Hill, Adrian V S; Spencer, Alexandra J

    2015-01-01

    The development of a highly efficacious and durable vaccine for malaria remains a top priority for global health researchers. Despite the huge rise in recognition of malaria as a global health problem and the concurrent rise in funding over the past 10-15 years, malaria continues to remain a widespread burden. The evidence of increasing resistance to anti-malarial drugs and insecticides is a growing concern. Hence, an efficacious and durable preventative vaccine for malaria is urgently needed. Vaccines are one of the most cost-effective tools and have successfully been used in the prevention and control of many diseases, however, the development of a vaccine for the Plasmodium parasite has proved difficult. Given the early success of whole sporozoite mosquito-bite delivered vaccination strategies, we know that a vaccine for malaria is an achievable goal, with sub-unit vaccines holding great promise as they are simple and cheap to both manufacture and deploy. However a major difficulty in development of sub-unit vaccines lies within choosing the appropriate antigenic target from the 5000 or so genes expressed by the parasite. Given the liver-stage of malaria represents a bottle-neck in the parasite's life cycle, there is widespread agreement that a multi-component sub-unit malaria vaccine should preferably contain a liver-stage target. In this article we review progress in identifying and screening Plasmodium falciparum liver-stage targets for use in a malaria vaccine. PMID:26441899

  3. Relationship of regulatory T cells to Plasmodium falciparum malaria symptomatology in a hypoendemic region

    PubMed Central

    2014-01-01

    Background Previous data have suggested that regulatory T cells (Tregs) balance protective immune responses with immune mediated pathology in malaria. This study aimed to determine to test the hypothesis that Treg proportions or absolute levels are associated with parasitaemia and malaria symptoms. Methods Treg cells were quantified by flow cytometry as CD4+ CD25+, Foxp3+, CD127low T cells. Three patient groups were assessed: patients with symptomatic Plasmodium falciparum malaria (S), subjects with asymptomatic P. falciparum parasitaemia (AS) and uninfected control individuals (C). Results S, AS and C groups had similar absolute numbers and percentage of Tregs (3.9%, 3.5% and 3.5% respectively). Levels of parasitaemia were not associated with Treg percentage (p = 0.47). Conclusion Neither relative nor absolute regulatory T cell numbers were found to be associated with malaria-related symptomatology in this study. Immune mechanisms other than Tregs are likely to be responsible for the state of asymptomatic P. falciparum parasitaemia in the Peruvian Amazon; but further study to explore these mechanisms is needed. PMID:24642188

  4. Plasmodium falciparum Malaria Endemicity in Indonesia in 2010

    PubMed Central

    Elyazar, Iqbal R. F.; Gething, Peter W.; Patil, Anand P.; Rogayah, Hanifah; Kusriastuti, Rita; Wismarini, Desak M.; Tarmizi, Siti N.; Baird, J. Kevin; Hay, Simon I.

    2011-01-01

    Background Malaria control programs require a detailed understanding of the contemporary spatial distribution of infection risk to efficiently allocate resources. We used model based geostatistics (MBG) techniques to generate a contemporary map of Plasmodium falciparum malaria risk in Indonesia in 2010. Methods Plasmodium falciparum Annual Parasite Incidence (PfAPI) data (2006–2008) were used to map limits of P. falciparum transmission. A total of 2,581 community blood surveys of P. falciparum parasite rate (PfPR) were identified (1985–2009). After quality control, 2,516 were included into a national database of age-standardized 2–10 year old PfPR data (PfPR2–10) for endemicity mapping. A Bayesian MBG procedure was used to create a predicted surface of PfPR2–10 endemicity with uncertainty estimates. Population at risk estimates were derived with reference to a 2010 human population count surface. Results We estimate 132.8 million people in Indonesia, lived at risk of P. falciparum transmission in 2010. Of these, 70.3% inhabited areas of unstable transmission and 29.7% in stable transmission. Among those exposed to stable risk, the vast majority were at low risk (93.39%) with the reminder at intermediate (6.6%) and high risk (0.01%). More people in western Indonesia lived in unstable rather than stable transmission zones. In contrast, fewer people in eastern Indonesia lived in unstable versus stable transmission areas. Conclusion While further feasibility assessments will be required, the immediate prospects for sustained control are good across much of the archipelago and medium term plans to transition to the pre-elimination phase are not unrealistic for P. falciparum. Endemicity in areas of Papua will clearly present the greatest challenge. This P. falciparum endemicity map allows malaria control agencies and their partners to comprehensively assess the region-specific prospects for reaching pre-elimination, monitor and evaluate the effectiveness of

  5. A World Malaria Map: Plasmodium falciparum Endemicity in 2007

    PubMed Central

    Hay, Simon I; Guerra, Carlos A; Gething, Peter W; Patil, Anand P; Tatem, Andrew J; Noor, Abdisalan M; Kabaria, Caroline W; Manh, Bui H; Elyazar, Iqbal R. F; Brooker, Simon; Smith, David L; Moyeed, Rana A; Snow, Robert W

    2009-01-01

    Background Efficient allocation of resources to intervene against malaria requires a detailed understanding of the contemporary spatial distribution of malaria risk. It is exactly 40 y since the last global map of malaria endemicity was published. This paper describes the generation of a new world map of Plasmodium falciparum malaria endemicity for the year 2007. Methods and Findings A total of 8,938 P. falciparum parasite rate (PfPR) surveys were identified using a variety of exhaustive search strategies. Of these, 7,953 passed strict data fidelity tests for inclusion into a global database of PfPR data, age-standardized to 2–10 y for endemicity mapping. A model-based geostatistical procedure was used to create a continuous surface of malaria endemicity within previously defined stable spatial limits of P. falciparum transmission. These procedures were implemented within a Bayesian statistical framework so that the uncertainty of these predictions could be evaluated robustly. The uncertainty was expressed as the probability of predicting correctly one of three endemicity classes; previously stratified to be an informative guide for malaria control. Population at risk estimates, adjusted for the transmission modifying effects of urbanization in Africa, were then derived with reference to human population surfaces in 2007. Of the 1.38 billion people at risk of stable P. falciparum malaria, 0.69 billion were found in Central and South East Asia (CSE Asia), 0.66 billion in Africa, Yemen, and Saudi Arabia (Africa+), and 0.04 billion in the Americas. All those exposed to stable risk in the Americas were in the lowest endemicity class (PfPR2−10 ≤ 5%). The vast majority (88%) of those living under stable risk in CSE Asia were also in this low endemicity class; a small remainder (11%) were in the intermediate endemicity class (PfPR2−10 > 5 to < 40%); and the remaining fraction (1%) in high endemicity (PfPR2−10 ≥ 40%) areas. High endemicity was widespread in the

  6. CRISPR-mediated genome editing of Plasmodium falciparum malaria parasites.

    PubMed

    Lee, Marcus Cs; Fidock, David A

    2014-01-01

    The development of the CRISPR-Cas system is revolutionizing genome editing in a variety of organisms. The system has now been used to manipulate the genome of Plasmodium falciparum, the most lethal malaria-causing species. The ability to generate gene deletions or nucleotide substitutions rapidly and economically promises to accelerate the analysis of novel drug targets and to help elucidate the function of specific genes or gene families, while complementing genome-wide association studies.

  7. Increased carboxyhemoglobin in adult falciparum malaria is associated with disease severity and mortality.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Kenangalem, Enny; Tjitra, Emiliana; Price, Ric N; Anstey, Nicholas M

    2013-09-01

    Heme oxygenase 1 expression is increased in pediatric patients with malaria. The carboxyhemoglobin level (a measure of heme oxygenase 1 activity) has not been assessed in adult patients with malaria. Results of pulse co-oximetry revealed that the mean carboxyhemoglobin level was elevated in 29 Indonesian adults with severe falciparum malaria (10%; 95% confidence interval [CI], 8%-13%) and in 20 with severe sepsis (8%; 95% CI, 5%-12%), compared with the mean levels in 32 patients with moderately severe malaria (7%; 95% CI, 5%-8%) and 36 controls (3.6%; 95% CI, 3%-5%; P < .001). An increased carboxyhemoglobin level was associated with an increased odds of death among patients with severe malaria (odds ratio, 1.2 per percentage point increase; 95% CI, 1.02-1.5). While also associated with severity and fatality, methemoglobin was only modestly increased in patients with severe malaria. Increased carboxyhemoglobin levels during severe malaria and sepsis may exacerbate organ dysfunction by reducing oxygen carriage and cautions against the use of adjunctive CO therapy, which was proposed on the basis of mouse models.

  8. Malaria, Plasmodium falciparum and its apicoplast.

    PubMed

    Kalanon, Ming; McFadden, Geoffrey I

    2010-06-01

    Malaria, which is caused by species of the parasite genus Plasmodium, remains a major global health problem. A vestigial plastid homologous with the chloroplasts of plants and algae was discovered in malaria and related parasites from the phylum Apicomplexa and has radically changed our view of the evolutionary origins of these disease-causing protists. We now recognize that this large group of parasites had a photosynthetic ancestry and were converted into parasitism early in the evolution of animals. Apicomplexans have probably been parasitizing the animal kingdom for more than 500 million years. The relic plastid persists in most apicomplexans and is an essential component. Perturbation of apicoplast function or inheritance results in parasite death, making the organelle a promising target for chemotherapy. Plastids, including those of malaria parasites, are essentially reduced endosymbiotic bacteria living inside a eukaryotic host. This means that plastids have bacterial-type metabolic pathways and housekeeping processes, all of which are vulnerable to antibacterial compounds. Indeed, many antibacterials kill malaria parasites by blocking essential processes in the plastid. Furthermore, a range of herbicides that target plastid metabolism of undesired plants are also parasiticidal, making them potential new leads for antimalarial drugs. In the present review, we examine the evolutionary origins of the malaria parasite's plastid by endosymbiosis and outline the recent findings on how the organelle imports nuclear-encoded proteins through a set of translocation machineries in the membranes that bound the organelle.

  9. Increased Oxidative Stress and Inflammation Independent of Body Adiposity in Diabetic and Nondiabetic Controls in falciparum Malaria

    PubMed Central

    Acquah, Samuel; Boampong, Johnson Nyarko; Eghan Jnr, Benjamin Ackon

    2016-01-01

    Information on the extent to which oxidative stress and inflammation occur in the presence of falciparum malaria and type 2 diabetes mellitus in the same individual is limited. This study sought to investigate the extent of inflammation and oxidative stress in adult uncomplicated malaria by measuring fasting levels of lipid peroxides, C-reactive protein (CRP), and total antioxidant power (TAP) before and during falciparum malaria, in 100 respondents with type 2 diabetes and 100 age-matched controls in the Cape Coast metropolis of Ghana. Also, body adiposity index, body mass index, and waist-to-hip ratio were computed. Before and during falciparum malaria, diabetes patients exhibited higher (P < 0.05) levels of CRP and peroxides than controls but TAP and BAI were comparable (P > 0.05) between the two groups. Baseline CRP correlated positively (r = 0.341, P = 0.002) with peroxide only in the diabetic group. During malaria, TAP level in both study groups declined (P < 0.05) by 80% of their baseline levels. CRP correlated negatively (r = −0.352, P = 0.011) with TAP in the control but not the diabetic group. Uncomplicated falciparum malaria elevated inflammation and peroxidation but decreased antioxidant power independent of adiposity. This finding may have implication on cardiovascular health. PMID:27298824

  10. Effect of arteether alpha/beta on uncomplicated falciparum malaria cases in Upper Assam.

    PubMed

    Mohapatra, P K; Khan, A M; Prakash, A; Mahanta, J; Srivastava, V K

    1996-11-01

    Thirty patients of uncomplicated Plasmodium falciparum malaria completed a clinical trial of arteether alpha/beta conducted in a malaria endemic tea garden of district Dibrugarh, Assam. Arteether was given intramuscularly in once a day dose of 150 mg for three consecutive days. The cure rate was 100 per cent with mean fever and parasite clearance time of 42.4 +/- 17.5 and 37.6 +/- 13.6 h respectively. Recrudescence/reinfection rate was 6.7 per cent. Palpable spleens of twenty out of twenty one cases on day 0 became non palpable within 28 days. Following the treatment, percentage of hemoglobin improved marginally with no remarkable change in total and differential leucocyte count. Arteether alpha/beta, besides being a potent and fast acting schizontocidal drug, also exhibited gametocytocidal action on P. falciparum. PMID:8979518

  11. Therapeutic efficacy test in malaria falciparum in Antioquia, Colombia

    PubMed Central

    Blair, Silvia; Carmona-Fonseca, Jaime; Piñeros, Juan G; Ríos, Alexandra; Álvarez, Tania; Álvarez, Gonzalo; Tobón, Alberto

    2006-01-01

    Objective Evaluate the frequency of failure of eight treatments for non-complicated malaria caused by Plasmodium falciparum in patients from Turbo (Urabá region), El Bagre and Zaragoza (Bajo Cauca region), applying the 1998 protocol of the World Health Organization (WHO). Monotherapies using chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ) and sulphadoxine-pyrimethamine (SP), and combinations using chloroquine-sulphadoxine-pyrimethamine (CQ-SP), amodiaquine-sulphadoxine-pyrimethamine (AQ-SP), mefloquine-sulphadoxine-pyrimethamine (MQ-SP) and artesunate-sulphadoxine-pyrimethamine (AS-SP), were examined. Methodology A balanced experimental design with eight groups. Samples were selected based on statistical and epidemiological criteria. Patients were followed for 21 to 28 days, including seven or eight parasitological and clinical evaluations, with an active search for defaulting patients. A non-blinded evaluation of the antimalarial treatment response (early failure, late failure, adequate response) was performed. Results Initially, the loss of patients to follow-up was higher than 40%, but the immediate active search for the cases and the monetary help for transportation expenses of patients, reduced the loss to 6%. The treatment failure was: CQ 82%, AQ 30%, MQ 4%, SP 24%, CQ-SP 17%, AQ-SP 2%, MQ-S-P 0%, AS-SP 3%. Conclusion The characteristics of an optimal epidemiological monitoring system of antimalarial treatment response in Colombia are discussed. It is proposed to focus this on early failure detection, by applying a screening test every two to three years, based on a seven to 14-day follow-up. Clinical and parasitological assessment would be carried out by a general physician and a field microscopist from the local hospital, with active measures to search for defaulter patients at follow-up. PMID:16504002

  12. Possible Clinical Failure of Artemether-Lumefantrine in an Italian Traveler with Uncomplicated Falciparum Malaria.

    PubMed Central

    Repetto, Ernestina C.; Traverso, Antonio; Giacomazzi, Claudio G.

    2011-01-01

    Artemisinin-combination therapies (ACTs) are recommended for the treatment of uncomplicated malaria in endemic areas with multidrug resistant Plasmodium falciparum. We report a case of possible artemether-lumefantrine clinical failure in an Italian traveler with uncomplicated P. falciparum malaria imported from Democratic Republic of Congo. PMID:22084655

  13. A Phase III, Randomized, Non-Inferiority Trial to Assess the Efficacy and Safety of Dihydroartemisinin-Piperaquine in Comparison with Artesunate-Mefloquine in Patients with Uncomplicated Plasmodium falciparum Malaria in Southern Laos

    PubMed Central

    Mayxay, Mayfong; Keomany, Sommay; Khanthavong, Maniphone; Souvannasing, Phoutthalavanh; Stepniewska, Kasia; Khomthilath, Tiengthong; Keola, Siamphay; Pongvongsa, Tiengkham; Phompida, Samlane; Ubben, David; Valecha, Neena; White, Nicholas J.; Newton, Paul N.

    2010-01-01

    We conducted an open, randomized clinical trial of oral dihydroartemisinin-piperaquine (DP) versus artesunate-mefloquine (AM) in 300 patients in Laos with uncomplicated Plasmodium falciparum malaria as part of a multicentre study in Asia. Survival analysis and adjustment for re-infection showed that the 63-day cure rates (95% confidence interval [CI]) were 100% for AM and 99.5% (96.4–99.8%) for DP. The 63-day cure rates per protocol were 99% (97 of 98) for AM and 99.5% (196 of 197) for DP (P = 0.55). The difference (AM minus DP) in cure rates (95% CI) was −0.5% (−5.1 to 2.0%), which is within the 5% non-inferiority margin. The median fever and parasite clearance times were also similar for AM and DP. The proportion of patients with at least one recorded potential adverse event was significantly higher in the AM group (38 of 87, 44%) than in the DP group (57 of 182, 31%) (relative risk = 0.6, 95% CI = 0.4–0.9; P = 0.04). Dihydroartemisinin-piperaquine is not inferior to AM in the treatment of uncomplicated P. falciparum malaria in Laos and is associated with fewer adverse effects. The results of this study were similar to those of the larger multicentre study. PMID:21118925

  14. Origin of the human malaria parasite Plasmodium falciparum in gorillas.

    PubMed

    Liu, Weimin; Li, Yingying; Learn, Gerald H; Rudicell, Rebecca S; Robertson, Joel D; Keele, Brandon F; Ndjango, Jean-Bosco N; Sanz, Crickette M; Morgan, David B; Locatelli, Sabrina; Gonder, Mary K; Kranzusch, Philip J; Walsh, Peter D; Delaporte, Eric; Mpoudi-Ngole, Eitel; Georgiev, Alexander V; Muller, Martin N; Shaw, George M; Peeters, Martine; Sharp, Paul M; Rayner, Julian C; Hahn, Beatrice H

    2010-09-23

    Plasmodium falciparum is the most prevalent and lethal of the malaria parasites infecting humans, yet the origin and evolutionary history of this important pathogen remain controversial. Here we develop a single-genome amplification strategy to identify and characterize Plasmodium spp. DNA sequences in faecal samples from wild-living apes. Among nearly 3,000 specimens collected from field sites throughout central Africa, we found Plasmodium infection in chimpanzees (Pan troglodytes) and western gorillas (Gorilla gorilla), but not in eastern gorillas (Gorilla beringei) or bonobos (Pan paniscus). Ape plasmodial infections were highly prevalent, widely distributed and almost always made up of mixed parasite species. Analysis of more than 1,100 mitochondrial, apicoplast and nuclear gene sequences from chimpanzees and gorillas revealed that 99% grouped within one of six host-specific lineages representing distinct Plasmodium species within the subgenus Laverania. One of these from western gorillas comprised parasites that were nearly identical to P. falciparum. In phylogenetic analyses of full-length mitochondrial sequences, human P. falciparum formed a monophyletic lineage within the gorilla parasite radiation. These findings indicate that P. falciparum is of gorilla origin and not of chimpanzee, bonobo or ancient human origin.

  15. Origin of the human malaria parasite Plasmodium falciparum in gorillas

    PubMed Central

    Liu, Weimin; Li, Yingying; Learn, Gerald H.; Rudicell, Rebecca S.; Robertson, Joel D.; Keele, Brandon F.; Ndjango, Jean-Bosco N.; Sanz, Crickette M.; Morgan, David B.; Locatelli, Sabrina; Gonder, Mary K.; Kranzusch, Philip J.; Walsh, Peter D.; Delaporte, Eric; Mpoudi-Ngole, Eitel; Georgiev, Alexander V.; Muller, Martin N.; Shaw, George M.; Peeters, Martine; Sharp, Paul M.; Rayner, Julian C.; Hahn, Beatrice H.

    2010-01-01

    Plasmodium falciparum is the most prevalent and lethal of the malaria parasites infecting humans, yet the origin and evolutionary history of this important pathogen remain controversial. Here, we developed a novel polymerase chain reaction based single genome amplification strategy to identify and characterize Plasmodium spp. DNA sequences in fecal samples of wild-living apes. Among nearly 3,000 specimens collected from field sites throughout central Africa, we found Plasmodium infection in chimpanzees (Pan troglodytes) and western gorillas (Gorilla gorilla), but not in eastern gorillas (Gorilla beringei) or bonobos (Pan paniscus). Ape plasmodial infections were highly prevalent, widely distributed, and almost always comprised of mixed parasite species. Analysis of more than 1,100 mitochondrial, apicoplast and nuclear gene sequences from chimpanzees and gorillas revealed that 99% grouped within one of six host-specific lineages representing distinct Plasmodium species within the subgenus Laverania. One of these from western gorillas was comprised of parasites that were nearly identical to P. falciparum. In phylogenetic analyses of full-length mitochondrial sequences, human P. falciparum formed a monophyletic lineage within the gorilla parasite radiation. These findings indicate that P. falciparum is of gorilla and not of chimpanzee, bonobo or ancient human origin. PMID:20864995

  16. 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

  17. CD36 T188G gene polymorphism and severe falciparum malaria in India.

    PubMed

    Das, A; Das, T K; Sahu, U; Das, B P; Kar, S K; Ranjit, M R

    2009-07-01

    Sequestration of parasitized erythrocytes (PE) in the microvasculature contributes directly to the virulence and severe pathology of Plasmodium falciparum malaria. The scavenger receptor CD36 appears to play an important role in PE adherence. Recently several mutations in the CD36 gene have been found to be associated with variability in susceptibility to P. falciparum infection in different ethnic populations. We investigated the possible association of T188G CD36 gene polymorphism with severe clinical manifestations of malaria in 95 adult patients with severe malaria admitted to SCB Medical College Hospital, Cuttack, Orissa, India ('severe' group) and 95 ethnically matched controls attending outpatient clinics at primary health centres ('mild' group). The frequency of the wild-type (T188T) allele of the CD36 gene was 0.91 in the 'severe' group and 0.78 in the 'mild' group of patients, while mutant (T188G) allele frequency was 0.09 in the severe group and 0.22 in the mild group. The Hardy-Weinberg equation indicates that the mutant allele is under selection pressure and disease association analysis shows that the presence of the heterozygote mutant allele renders protection against severe malaria (chi(2)=10.67, odds ratio=3.51, 95% CI 1.67-7.36). PMID:19136129

  18. Reversibility of retinal microvascular changes in severe falciparum malaria.

    PubMed

    Maude, Richard J; Kingston, Hugh W F; Joshi, Sonia; Mohanty, Sanjib; Mishra, Saroj K; White, Nicholas J; Dondorp, Arjen M

    2014-09-01

    Malarial retinopathy allows detailed study of central nervous system vascular pathology in living patients with severe malaria. An adult with cerebral malaria is described who had prominent retinal whitening with corresponding retinal microvascular obstruction, vessel dilatation, increased vascular tortuosity, and blood retinal barrier leakage with decreased visual acuity, all of which resolved on recovery. Additional study of these features and their potential role in elucidating the pathogenesis of cerebral malaria is warranted.

  19. Proteomic Investigation of Falciparum and Vivax Malaria for Identification of Surrogate Protein Markers

    PubMed Central

    Ray, Sandipan; Renu, Durairaj; Srivastava, Rajneesh; Gollapalli, Kishore; Taur, Santosh; Jhaveri, Tulip; Dhali, Snigdha; Chennareddy, Srinivasarao; Potla, Ankit; Dikshit, Jyoti Bajpai; Srikanth, Rapole; Gogtay, Nithya; Thatte, Urmila; Patankar, Swati; Srivastava, Sanjeeva

    2012-01-01

    This study was conducted to analyze alterations in the human serum proteome as a consequence of infection by malaria parasites Plasmodium falciparum and P. vivax to obtain mechanistic insights about disease pathogenesis, host immune response, and identification of potential protein markers. Serum samples from patients diagnosed with falciparum malaria (FM) (n = 20), vivax malaria (VM) (n = 17) and healthy controls (HC) (n = 20) were investigated using multiple proteomic techniques and results were validated by employing immunoassay-based approaches. Specificity of the identified malaria related serum markers was evaluated by means of analysis of leptospirosis as a febrile control (FC). Compared to HC, 30 and 31 differentially expressed and statistically significant (p<0.05) serum proteins were identified in FM and VM respectively, and almost half (46.2%) of these proteins were commonly modulated due to both of the plasmodial infections. 13 proteins were found to be differentially expressed in FM compared to VM. Functional pathway analysis involving the identified proteins revealed the modulation of different vital physiological pathways, including acute phase response signaling, chemokine and cytokine signaling, complement cascades and blood coagulation in malaria. A panel of identified proteins consists of six candidates; serum amyloid A, hemopexin, apolipoprotein E, haptoglobin, retinol-binding protein and apolipoprotein A-I was used to build statistical sample class prediction models. By employing PLS-DA and other classification methods the clinical phenotypic classes (FM, VM, FC and HC) were predicted with over 95% prediction accuracy. Individual performance of three classifier proteins; haptoglobin, apolipoprotein A-I and retinol-binding protein in diagnosis of malaria was analyzed using receiver operating characteristic (ROC) curves. The discrimination of FM, VM, FC and HC groups on the basis of differentially expressed serum proteins demonstrates

  20. Artemisinin-naphthoquine for treating uncomplicated Plasmodium falciparum malaria

    PubMed Central

    Isba, Rachel; Zani, Babalwa; Gathu, Michael; Sinclair, David

    2015-01-01

    Background The World Health Organization (WHO) recommends artemisinin-based combination therapy (ACT) for treating people with Plasmodium falciparum malaria. Five combinations are currently recommended, all administered over three days. Artemisinin-naphthoquine is a new combination developed in China, which is being marketed as a one-day treatment. Although shorter treatment courses may improve adherence, the WHO recommends at least three days of the short-acting artemisinin component to eliminate 90% P. falciparum parasites in the bloodstream, before leaving the longer-acting partner drug to clear the remaining parasites. Objectives To evaluate the efficacy and safety of the artemisinin-naphthoquine combination for treating adults and children with uncomplicated P. falciparum malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL) published in The Cochrane Library; MEDLINE; EMBASE; and LILACS up to January 2015. We also searched the metaRegister of Controlled Trials (mRCT) using 'malaria' and 'arte* OR dihydroarte*' as search terms. Selection criteria Randomized controlled trials comparing artemisinin-naphthoquine combinations with established WHO-recommended ACTs for the treatment of adults and children with uncomplicated malaria due to P. falciparum. Data collection and analysis Two review authors independently assessed trials for eligibility and risk of bias, and extracted data. We analysed primary outcomes in line with the WHO 'Protocol for assessing and monitoring antimalarial drug efficacy' and compared drugs using risk ratios (RR) and 95% confidence intervals (CI). Secondary outcomes were effects on gametocytes, haemoglobin, and adverse events. We assessed the quality of evidence using the GRADE approach. Main results Four trials, enrolling 740 adults and children, met the inclusion criteria. Artemisinin-naphthoquine was administered as a single dose (two

  1. Anti-Plasmodium falciparum invasion ligand antibodies in a low malaria transmission region, Loreto, Peru

    PubMed Central

    2012-01-01

    Background Erythrocyte invasion by Plasmodium falciparum is a complex process that involves two families; Erythrocyte Binding-Like (EBL) and the Reticulocyte Binding-Like (PfRh) proteins. Antibodies that inhibit merozoite attachment and invasion are believed to be important in mediating naturally acquired immunity and immunity generated by parasite blood stage vaccine candidates. The hypotheses tested in this study were 1) that antibody responses against specific P. falciparum invasion ligands (EBL and PfRh) differ between symptomatic and asymptomatic individuals living in the low-transmission region of the Peruvian Amazon and 2), such antibody responses might have an association, either direct or indirect, with clinical immunity observed in asymptomatically parasitaemic individuals. Methods ELISA was used to assess antibody responses (IgG, IgG1 and IgG3) against recombinant P. falciparum invasion ligands of the EBL (EBA-175, EBA-181, EBA-140) and PfRh families (PfRh1, PfRh2a, PfRh2b, PfRh4 and PfRh5) in 45 individuals infected with P. falciparum from Peruvian Amazon. Individuals were classified as having symptomatic malaria (N=37) or asymptomatic infection (N=8). Results Antibody responses against both EBL and PfRh family proteins were significantly higher in asymptomatic compared to symptomatic individuals, demonstrating an association with clinical immunity. Significant differences in the total IgG responses were observed with EBA-175, EBA-181, PfRh2b, and MSP119 (as a control). IgG1 responses against EBA-181, PfRh2a and PfRh2b were significantly higher in the asymptomatic individuals. Total IgG antibody responses against PfRh1, PfRh2a, PfRh2b, PfRh5, EBA-175, EBA-181 and MSP119 proteins were negatively correlated with level of parasitaemia. IgG1 responses against EBA-181, PfRh2a and PfRh2b and IgG3 response for PfRh2a were also negatively correlated with parasitaemia. Conclusions These data suggest that falciparum malaria patients who develop clinical immunity

  2. Molecular Epidemiology of Plasmodium falciparum Malaria Outbreak, Tumbes, Peru, 2010-2012.

    PubMed

    Baldeviano, G Christian; Okoth, Sheila Akinyi; Arrospide, Nancy; Gonzalez, Rommell V; Sánchez, Juan F; Macedo, Silvia; Conde, Silvia; Tapia, L Lorena; Salas, Carola; Gamboa, Dionicia; Herrera, Yeni; Edgel, Kimberly A; Udhayakumar, Venkatachalam; Lescano, Andrés G

    2015-05-01

    During 2010-2012, an outbreak of 210 cases of malaria occurred in Tumbes, in the northern coast of Peru, where no Plasmodium falciparum malaria case had been reported since 2006. To identify the source of the parasite causing this outbreak, we conducted a molecular epidemiology investigation. Microsatellite typing showed an identical genotype in all 54 available isolates. This genotype was also identical to that of parasites isolated in 2010 in the Loreto region of the Peruvian Amazon and closely related to clonet B, a parasite lineage previously reported in the Amazon during 1998-2000. These findings are consistent with travel history of index case-patients. DNA sequencing revealed mutations in the Pfdhfr, Pfdhps, Pfcrt, and Pfmdr1 loci, which are strongly associated with resistance to chloroquine and sulfadoxine/pyrimethamine, and deletion of the Pfhrp2 gene. These results highlight the need for timely molecular epidemiology investigations to trace the parasite source during malaria reintroduction events.

  3. High prevalence of mefloquine-resistant falciparum malaria in eastern Thailand.

    PubMed Central

    Fontanet, A. L.; Johnston, D. B.; Walker, A. M.; Rooney, W.; Thimasarn, K.; Sturchler, D.; Macdonald, M.; Hours, M.; Wirth, D. F.

    1993-01-01

    In order to assess the risk and predictors of mefloquine resistance we monitored a cohort of 113 patients in eastern Thailand who had been treated for uncomplicated falciparum malaria with a single dose of 15 mg/kg of the drug and followed up for 42 days. The overall treatment failure rate at day 42 was 59.1% (95% confidence interval (CI) = 50%, 68%) with only 2.7% of the patients being lost to follow-up. There were 6.4% RIII, 20.9% RII, 31.8% RI, and 40.9% sensitive responses, based on a modified WHO classification. A low haemoglobin level on the day of treatment and diarrhoea during the first two days after treatment were independent predictors of treatment failure. These findings remained statistically significant in a Cox proportional hazards model, after controlling for other baseline characteristics and adverse effects. Although a history of digestive disorders prior to treatment was associated with diarrhoea on day 2 (P = 0.024), it was in itself not a predictor of treatment failure (adjusted hazard ratio = 1.16; 95% CI = 0.35, 2.14). A total of 60 patients with an R response were hospitalized for 7 days to receive supervised treatment with quinine-tetracycline. Only three had a positive thick smear for asexual forms of Plasmodium falciparum 14 days later, and quinine-tetracycline therefore remains a good alternative treatment for mefloquine-resistant falciparum malaria. PMID:8324857

  4. Circumsporozoite antibodies and falciparum malaria incidence in children living in a malaria endemic area*

    PubMed Central

    Pang, L. W.; Limsomwong, N.; Karwacki, J.; Webster, H. K.

    1988-01-01

    In a case—control study we examined the association of Plasmodium falciparum circumsporozoite antibodies (anti-R32tet32) with subsequent P. falciparum infections. A study population of 140 children living in an endemic area was followed longitudinally for 25 weeks with weekly blood smears for malaria parasites and, once every two weeks, serum samples for circumsporozoite antibody determinations. From the malaria cases, antibody measurements occurring between two and six weeks prior to the onset of parasitaemia were utilized. For each case, two controls were selected. The results from 17 cases and 34 controls failed to show a statistically significant difference in antibody levels prior to the infection (P=0.07, one-tailed Student's t-test). However, 8 of the 17 cases had antibody present, indicating a level that was not protective against patent infection. PMID:3048760

  5. South American Plasmodium falciparum after the malaria eradication era: clonal population expansion and survival of the fittest hybrids.

    PubMed

    Griffing, Sean M; Mixson-Hayden, Tonya; Sridaran, Sankar; Alam, Md Tauqeer; McCollum, Andrea M; Cabezas, César; Marquiño Quezada, Wilmer; Barnwell, John W; De Oliveira, Alexandre Macedo; Lucas, Carmen; Arrospide, Nancy; Escalante, Ananias A; Bacon, David J; Udhayakumar, Venkatachalam

    2011-01-01

    Malaria has reemerged in many regions where once it was nearly eliminated. Yet the source of these parasites, the process of repopulation, their population structure, and dynamics are ill defined. Peru was one of malaria eradication's successes, where Plasmodium falciparum was nearly eliminated for two decades. It reemerged in the 1990s. In the new era of malaria elimination, Peruvian P. falciparum is a model of malaria reinvasion. We investigated its population structure and drug resistance profiles. We hypothesized that only populations adapted to local ecological niches could expand and repopulate and originated as vestigial populations or recent introductions. We investigated the genetic structure (using microsatellites) and drug resistant genotypes of 220 parasites collected from patients immediately after peak epidemic expansion (1999-2000) from seven sites across the country. The majority of parasites could be grouped into five clonal lineages by networks and AMOVA. The distribution of clonal lineages and their drug sensitivity profiles suggested geographic structure. In 2001, artesunate combination therapy was introduced in Peru. We tested 62 parasites collected in 2006-2007 for changes in genetic structure. Clonal lineages had recombined under selection for the fittest parasites. Our findings illustrate that local adaptations in the post-eradication era have contributed to clonal lineage expansion. Within the shifting confluence of drug policy and malaria incidence, populations continue to evolve through genetic outcrossing influenced by antimalarial selection pressure. Understanding the population substructure of P. falciparum has implications for vaccine, drug, and epidemiologic studies, including monitoring malaria during and after the elimination phase.

  6. The folate metabolic network of Falciparum malaria.

    PubMed

    Salcedo-Sora, J Enrique; Ward, Steve A

    2013-03-01

    The targeting of key enzymes in the folate pathway continues to be an effective chemotherapeutic approach that has earned antifolate drugs a valuable position in the medical pharmacopoeia. The successful therapeutic use of antifolates as antimalarials has been a catalyst for ongoing research into the biochemistry of folate and pterin biosynthesis in malaria parasites. However, our understanding of the parasites folate metabolism remains partial and patchy, especially in relation to the shikimate pathway, the folate cycle, and folate salvage. A sizeable number of potential folate targets remain to be characterised. Recent reports on the parasite specific transport of folate precursors that would normally be present in the human host awaken previous hypotheses on the salvage of folate precursors or by-products. As the parasite progresses through its life-cycle it encounters very contrasting host cell environments that present radically different metabolic milieus and biochemical challenges. It would seem probable that as the parasite encounters differing environments it would need to modify its biochemistry. This would be reflected in the folate homeostasis in Plasmodium. Recent drug screening efforts and insights into folate membrane transport substantiate the argument that folate metabolism may still offer unexplored opportunities for therapeutic attack.

  7. Response of falciparum malaria to different antimalarials in Myanmar.

    PubMed Central

    Ejov, M. N.; Tun, T.; Aung, S.; Sein, K.

    1999-01-01

    The purpose of the study was to ascertain the therapeutic efficacy of different treatments for uncomplicated falciparum malaria in the hospitals in Sagaing, northern and eastern Shan, to facilitate updating the existing national antimalarial drug policy. The proposed 14-day trial for monitoring the efficacy of treatments of uncomplicated falciparum malaria is an efficient method for identifying treatment failure patterns at the intermediate level (township hospital) in the Union of Myanmar. Minimal clinical and parasitological data for days 0-14 were required to classify treatment failure and success. Clinical and parasitiological responses on day 3 and days 4-14 were used as clear examples of early and late treatment failure, respectively. Mefloquine is five times more likely to be effective than chloroquine and sulfadoxine pyrimethamine (S-P), whereas chloroquine and S-P treatments have nearly identical failure patterns. The alarming frequency of clinical and parasitological failure (failure rate > 50%) following chloroquine treatment was reported in Sagaing and following S-P treatment in Sagaing and eastern Shan. PMID:10212515

  8. [Malaria].

    PubMed

    Burchard, G D

    2014-02-01

    Malaria is the most important infectious disease imported by travelers and migrants from tropical and subtropical areas. It is imported quite frequently. It is a life-threatening disease. Symptoms are nonspecific and cannot easily be distinguished from a wide range of other febrile conditions. Therefore, travel history must be taken in all patients with fever of unknown origin and malaria diagnostics must be performed immediately on suspicion of malaria. Uncomplicated falciparum malaria should be treated in the hospital with either atovaquone-proguanil or with an artemisinin-based combination preparation. If there is evidence of severe malaria, the patient must be moved to an intensive care unit. The antiparasitic agent of choice is then artesunate.

  9. A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria.

    PubMed

    Mbengue, Alassane; Bhattacharjee, Souvik; Pandharkar, Trupti; Liu, Haining; Estiu, Guillermina; Stahelin, Robert V; Rizk, Shahir S; Njimoh, Dieudonne L; Ryan, Yana; Chotivanich, Kesinee; Nguon, Chea; Ghorbal, Mehdi; Lopez-Rubio, Jose-Juan; Pfrender, Michael; Emrich, Scott; Mohandas, Narla; Dondorp, Arjen M; Wiest, Olaf; Haldar, Kasturi

    2015-04-30

    Artemisinins are the cornerstone of anti-malarial drugs. Emergence and spread of resistance to them raises risk of wiping out recent gains achieved in reducing worldwide malaria burden and threatens future malaria control and elimination on a global level. Genome-wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by the PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase, as well as its lipid product phosphatidylinositol-3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signalling in which transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination.

  10. A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria

    PubMed Central

    Mbengue, Alassane; Bhattacharjee, Souvik; Pandharkar, Trupti; Liu, Haining; Estiu, Guillermina; Stahelin, Robert V.; Rizk, Shahir; Njimoh, Dieudonne L.; Ryan, Yana; Chotivanich, Kesinee; Nguon, Chea; Ghorbal, Mehdi; Lopez-Rubio, Jose-Juan; Pfrender, Michael; Emrich, Scott; Mohandas, Narla; Dondorp, Arjen M.; Wiest, Olaf; Haldar, Kasturi

    2015-01-01

    Artemisinins are the corner stone of anti-malarial drugs1. Emergence and spread of resistance to them2–4 raises risk of wiping out recent gains achieved in reducing world-wide malaria burden and threatens future malaria control and elimination on a global level. Genome wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance5–10. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase as well as its lipid product phosphatidylinositol 3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signaling, where transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination. PMID:25874676

  11. Artesunate plus pyronaridine for treating uncomplicated Plasmodium falciparum malaria

    PubMed Central

    Bukirwa, Hasifa; Unnikrishnan, B; Kramer, Christine V; Sinclair, David; Nair, Suma; Tharyan, Prathap

    2014-01-01

    Background The World Health Organization (WHO) recommends that people with uncomplicated Plasmodium falciparum malaria are treated using Artemisinin-based Combination Therapy (ACT). ACT combines three-days of a short-acting artemisinin derivative with a longer-acting antimalarial which has a different mode of action. Pyronaridine has been reported as an effective antimalarial over two decades of use in parts of Asia, and is currently being evaluated as a partner drug for artesunate. Objectives To evaluate the efficacy and safety of artesunate-pyronaridine compared to alternative ACTs for treating people with uncomplicated P. falciparum malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; ClinicalTrials.gov; the metaRegister of Controlled Trials (mRCT); and the WHO International Clinical Trials Search Portal up to 16 January 2014. We searched reference lists and conference abstracts, and contacted experts for information about ongoing and unpublished trials. Selection criteria Randomized controlled trials of artesunate-pyronaridine versus other ACTs in adults and children with uncomplicated P. falciparum malaria. For the safety analysis, we also included adverse events data from trials comparing any treatment regimen containing pyronaridine with regimens not containing pyronaridine. Data collection and analysis Two authors independently assessed trial eligibility and risk of bias, and extracted data. We combined dichotomous data using risk ratios (RR) and continuous data using mean differences (MD), and presented all results with a 95% confidence interval (CI). We used the GRADE approach to assess the quality of evidence. Main results We included six randomized controlled trials enrolling 3718 children and adults. Artesunate-pyronaridine versus artemether-lumefantrine In two multicentre trials, enrolling

  12. Therapy of Falciparum Malaria in Sub-Saharan Africa: from Molecule to Policy

    PubMed Central

    Winstanley, Peter; Ward, Stephen; Snow, Robert; Breckenridge, Alasdair

    2004-01-01

    The burden of falciparum malaria remains as great as ever, and, as has probably always been the case, it is carried mainly by tropical Africa. Of the various means available for the control of malaria, the use of effective drugs remains the most important and is likely to remain so for a considerable time to come. Unfortunately, the extensive development of resistance by the parasite threatens the utility of most of the affordable classes of drug: the development of novel antimalarials has never been more urgently needed. Any attempt to understand the vast complexities of falciparum malaria in Africa requires an ability to think “from molecule to policy.” In consequence, the review ambitiously tries to examine the current pharmacopeia, the process by which new drugs are developed and the ways in which drugs are actually used, in both the formal and informal health sectors. The informal sector is particularly important in Africa, where around half of all antimalarial treatments are bought from informal outlets and taken at home without supervision by health care professionals: the potential impact of adherence on clinical outcome is discussed. Given that the full costs are carried by the patient in a large proportion of cases, the importance of drug affordability is explored. The review also discusses the splicing of new drugs into national policy. The various parameters that feed into deliberations on changes in drug policy are discussed. PMID:15258096

  13. Genome editing in the human malaria parasite Plasmodium falciparum using the CRISPR-Cas9 system.

    PubMed

    Ghorbal, Mehdi; Gorman, Molly; Macpherson, Cameron Ross; Martins, Rafael Miyazawa; Scherf, Artur; Lopez-Rubio, Jose-Juan

    2014-08-01

    Genome manipulation in the malaria parasite Plasmodium falciparum remains largely intractable and improved genomic tools are needed to further understand pathogenesis and drug resistance. We demonstrated the CRISPR-Cas9 system for use in P. falciparum by disrupting chromosomal loci and generating marker-free, single-nucleotide substitutions with high efficiency. Additionally, an artemisinin-resistant strain was generated by introducing a previously implicated polymorphism, thus illustrating the value of efficient genome editing in malaria research.

  14. Increased asymmetric dimethylarginine in severe falciparum malaria: association with impaired nitric oxide bioavailability and fatal outcome.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Tjitra, Emiliana; Gitawati, Retno; Darcy, Christabelle J; Jones, Catherine; Kenangalem, Enny; McNeil, Yvette R; Granger, Donald L; Lopansri, Bert K; Weinberg, J Brice; Price, Ric N; Duffull, Stephen B; Celermajer, David S; Anstey, Nicholas M

    2010-04-01

    Asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), is a predictor of mortality in critical illness. Severe malaria (SM) is associated with decreased NO bioavailability, but the contribution of ADMA to the pathogenesis of impaired NO bioavailability and adverse outcomes in malaria is unknown. In adults with and without falciparum malaria, we tested the hypotheses that plasma ADMA would be: 1) increased in proportion to disease severity, 2) associated with impaired vascular and pulmonary NO bioavailability and 3) independently associated with increased mortality. We assessed plasma dimethylarginines, exhaled NO concentrations and endothelial function in 49 patients with SM, 78 with moderately severe malaria (MSM) and 19 healthy controls (HC). Repeat ADMA and endothelial function measurements were performed in patients with SM. Multivariable regression was used to assess the effect of ADMA on mortality and NO bioavailability. Plasma ADMA was increased in SM patients (0.85 microM; 95% CI 0.74-0.96) compared to those with MSM (0.54 microM; 95%CI 0.5-0.56) and HCs (0.64 microM; 95%CI 0.58-0.70; p<0.001). ADMA was an independent predictor of mortality in SM patients with each micromolar elevation increasing the odds of death 18 fold (95% CI 2.0-181; p = 0.01). ADMA was independently associated with decreased exhaled NO (r(s) = -0.31) and endothelial function (r(s) = -0.32) in all malaria patients, and with reduced exhaled NO (r(s) = -0.72) in those with SM. ADMA is increased in SM and associated with decreased vascular and pulmonary NO bioavailability. Inhibition of NOS by ADMA may contribute to increased mortality in severe malaria.

  15. Role of S180L polymorphism in etiology of malaria caused by Plasmodium falciparum in a small group of Pakistani population.

    PubMed

    Nawaz, Syed Kashif; Ahmed, Bisma; Arshad, Najma; Rani, Asima; Rasool, Hamadia; Arshad, Muhammad

    2015-01-01

    The aim of our study was to investigate the role of S180L polymorphism in modulation of acquisition of malaria caused by Plasmodium falciparum in a small group of Pakistani population. A total of 133 individuals including 60 controls and 73 patients of malaria, caused by Plasmodium falciparum, were genotyped using allele-specific PCR. Ninety-two samples successfully demonstrated the PCR amplification results, while forty-one samples could not be genotyped due to failure in PCR amplification. The allele frequency for S180L polymorphism was deviant from Hardy-Weinberg equilibrium (HWE) of the population under observation. Association was found between the observed polymorphism and the occurrence of malaria caused by Plasmodium falciparum (p = 0.01). Chances of malaria caused by Plasmodium falciparum were low in CC genotype carriers in comparison to other genotypes (Odds ratio: 0.3016; 95% CI: 0.124-0.729). The present findings suggest that S180L polymorphism is important in modulating the probability of acquisition of malaria caused by Plasmodium falciparum in Pakistani population. The CC genotype plays a protective role in local population against this type of malaria.

  16. Economic access to effective drugs for falciparum malaria.

    PubMed

    Panosian, Claire B

    2005-03-01

    The increasing death toll from drug-resistant falciparum malaria is cause for international concern. In 2002, the US Agency for International Development commissioned the Institute of Medicine (IOM) to recommend global actions to ensure the broadest possible access to new, effective antimalarial treatments. In a report issued in 2004, the IOM Committee on Economics of Antimalarial Drugs recommended a global subsidy of 300 million dollars to 500 million dollars per year to replace increasingly ineffective drugs with coformulated artemisinin combination treatments to be distributed through public and private channels in affected areas. This approach allows the existing market to support the switch to new drugs and keeps treatment costs for consumers at levels similar to the current price of chloroquine. The leverage of an international subsidy of combination therapy can also discourage the distribution of monotherapies (such as solo artemisinins), the use of which might foster increasing resistance to antimalarial drugs in the future. PMID:15714418

  17. Imputation-Based Population Genetics Analysis of Plasmodium falciparum Malaria Parasites

    PubMed Central

    Samad, Hanif; Coll, Francesc; Preston, Mark D.; Ocholla, Harold; Fairhurst, Rick M.; Clark, Taane G.

    2015-01-01

    Whole-genome sequencing technologies are being increasingly applied to Plasmodium falciparum clinical isolates to identify genetic determinants of malaria pathogenesis. However, genome-wide discovery methods, such as haplotype scans for signatures of natural selection, are hindered by missing genotypes in sequence data. Poor correlation between single nucleotide polymorphisms (SNPs) in the P. falciparum genome complicates efforts to apply established missing-genotype imputation methods that leverage off patterns of linkage disequilibrium (LD). The accuracy of state-of-the-art, LD-based imputation methods (IMPUTE, Beagle) was assessed by measuring allelic r2 for 459 P. falciparum samples from malaria patients in 4 countries: Thailand, Cambodia, Gambia, and Malawi. In restricting our analysis to 86k high-quality SNPs across the populations, we found that the complete-case analysis was restricted to 21k SNPs (24.5%), despite no single SNP having more than 10% missing genotypes. The accuracy of Beagle in filling in missing genotypes was consistently high across all populations (allelic r2, 0.87-0.96), but the performance of IMPUTE was mixed (allelic r2, 0.34-0.99) depending on reference haplotypes and population. Positive selection analysis using Beagle-imputed haplotypes identified loci involved in resistance to chloroquine (crt) in Thailand, Cambodia, and Gambia, sulfadoxine-pyrimethamine (dhfr, dhps) in Cambodia, and artemisinin (kelch13) in Cambodia. Tajima’s D-based analysis identified genes under balancing selection that encode well-characterized vaccine candidates: apical merozoite antigen 1 (ama1) and merozoite surface protein 1 (msp1). In contrast, the complete-case analysis failed to identify any well-validated drug resistance or candidate vaccine loci, except kelch13. In a setting of low LD and modest levels of missing genotypes, using Beagle to impute P. falciparum genotypes is a viable strategy for conducting accurate large-scale population genetics and

  18. Imputation-based population genetics analysis of Plasmodium falciparum malaria parasites.

    PubMed

    Samad, Hanif; Coll, Francesc; Preston, Mark D; Ocholla, Harold; Fairhurst, Rick M; Clark, Taane G

    2015-04-01

    Whole-genome sequencing technologies are being increasingly applied to Plasmodium falciparum clinical isolates to identify genetic determinants of malaria pathogenesis. However, genome-wide discovery methods, such as haplotype scans for signatures of natural selection, are hindered by missing genotypes in sequence data. Poor correlation between single nucleotide polymorphisms (SNPs) in the P. falciparum genome complicates efforts to apply established missing-genotype imputation methods that leverage off patterns of linkage disequilibrium (LD). The accuracy of state-of-the-art, LD-based imputation methods (IMPUTE, Beagle) was assessed by measuring allelic r2 for 459 P. falciparum samples from malaria patients in 4 countries: Thailand, Cambodia, Gambia, and Malawi. In restricting our analysis to 86 k high-quality SNPs across the populations, we found that the complete-case analysis was restricted to 21k SNPs (24.5%), despite no single SNP having more than 10% missing genotypes. The accuracy of Beagle in filling in missing genotypes was consistently high across all populations (allelic r2, 0.87-0.96), but the performance of IMPUTE was mixed (allelic r2, 0.34-0.99) depending on reference haplotypes and population. Positive selection analysis using Beagle-imputed haplotypes identified loci involved in resistance to chloroquine (crt) in Thailand, Cambodia, and Gambia, sulfadoxine-pyrimethamine (dhfr, dhps) in Cambodia, and artemisinin (kelch13) in Cambodia. Tajima's D-based analysis identified genes under balancing selection that encode well-characterized vaccine candidates: apical merozoite antigen 1 (ama1) and merozoite surface protein 1 (msp1). In contrast, the complete-case analysis failed to identify any well-validated drug resistance or candidate vaccine loci, except kelch13. In a setting of low LD and modest levels of missing genotypes, using Beagle to impute P. falciparum genotypes is a viable strategy for conducting accurate large-scale population genetics and

  19. Imputation-based population genetics analysis of Plasmodium falciparum malaria parasites.

    PubMed

    Samad, Hanif; Coll, Francesc; Preston, Mark D; Ocholla, Harold; Fairhurst, Rick M; Clark, Taane G

    2015-04-01

    Whole-genome sequencing technologies are being increasingly applied to Plasmodium falciparum clinical isolates to identify genetic determinants of malaria pathogenesis. However, genome-wide discovery methods, such as haplotype scans for signatures of natural selection, are hindered by missing genotypes in sequence data. Poor correlation between single nucleotide polymorphisms (SNPs) in the P. falciparum genome complicates efforts to apply established missing-genotype imputation methods that leverage off patterns of linkage disequilibrium (LD). The accuracy of state-of-the-art, LD-based imputation methods (IMPUTE, Beagle) was assessed by measuring allelic r2 for 459 P. falciparum samples from malaria patients in 4 countries: Thailand, Cambodia, Gambia, and Malawi. In restricting our analysis to 86 k high-quality SNPs across the populations, we found that the complete-case analysis was restricted to 21k SNPs (24.5%), despite no single SNP having more than 10% missing genotypes. The accuracy of Beagle in filling in missing genotypes was consistently high across all populations (allelic r2, 0.87-0.96), but the performance of IMPUTE was mixed (allelic r2, 0.34-0.99) depending on reference haplotypes and population. Positive selection analysis using Beagle-imputed haplotypes identified loci involved in resistance to chloroquine (crt) in Thailand, Cambodia, and Gambia, sulfadoxine-pyrimethamine (dhfr, dhps) in Cambodia, and artemisinin (kelch13) in Cambodia. Tajima's D-based analysis identified genes under balancing selection that encode well-characterized vaccine candidates: apical merozoite antigen 1 (ama1) and merozoite surface protein 1 (msp1). In contrast, the complete-case analysis failed to identify any well-validated drug resistance or candidate vaccine loci, except kelch13. In a setting of low LD and modest levels of missing genotypes, using Beagle to impute P. falciparum genotypes is a viable strategy for conducting accurate large-scale population genetics and

  20. Epidemiological and clinical features of Plasmodium falciparum malaria in united nations personnel in Western Bahr el Ghazal State, South Sudan.

    PubMed

    He, Dengming; Zhang, Yuqi; Liu, Xiaofeng; Guo, Shimin; Zhao, Donghong; Zhu, Yunjie; Li, Huaidong; Kong, Li

    2013-01-01

    Western Bahr el Ghazal State is located in northwestern South Sudan, which is a tropical area subject to Plasmodium falciparum malaria epidemics. The aim of this study is to explore the epidemiological and clinical features of Plasmodium falciparum malaria in United Nations personnel stationed in this area. From July 2006 to June 2009, epidemiological data and medical records of 678 patients with Plasmodium falciparum malaria at the U.N. level 2 hospital were analyzed. The U.N. personnel were divided into individuals not immune to Plasmodium falciparum and individuals semi-immune to Plasmodium falciparum. The patients were divided into a chemoprophylaxis group (non-immune individuals who complied with the chemoprophylaxis regimen, 582 cases) and a no/incomplete chemoprophylaxis group (non-immune individuals who either did not fully comply with chemoprophylaxis or did not use it at all and semi-immune individuals who did not use chemoprophylaxis, 96 cases). Overall morbidity was about 11.3%. There was a significant difference in the morbidity of semi-immune and non-immune individuals (1.3% vs. 15.1%, P<0.001). Out of the total, 82.9% of cases occurred during the rainy season. The incidence of fever in the chemoprophylaxis group was significantly lower than in the no/incomplete chemoprophylaxis group (36.8% vs. 96.9%, P<0.001). Significant differences were observed between the two groups with respect to all other malaria-like symptoms except gastrointestinal symptoms, serum glucose level, platelet count, and alanine aminotransferase level. The incidence of complications was 1.2% (chemoprophylaxis group) and 44.8% (no/incomplete chemoprophylaxis group).The most common complication was thrombocytopenia, which was seen in 40.6% of the no/incomplete chemoprophylaxis group. In summary, Plasmodium falciparum malaria mainly occurred in rainy season. Gastrointestinal symptoms are an important precursor of malaria. Blood smears and rapid diagnostic tests should be performed

  1. The use of activated protein C in severe Plasmodium falciparum malaria.

    PubMed

    Rankin, L G; Austin, D L H

    2007-06-01

    A 56-year-old man presented to a peripheral hospital in New Zealand with severe Plasmodium falciparum malaria with cerebral involvement and subsequently developed multi-system organ failure. Activated protein C was used in an attempt to stop the cascade of events into multi-organ failure. Severe infection with P. falciparum is life-threatening and appears to activate a hypercoagulable state similar to that of severe sepsis. Activated protein C is currently used in the treatment of severe sepsis and may provide a new adjuvant therapy for severe P. falciparum malaria.

  2. Magnetic resonance imaging of the brain in adults with severe falciparum malaria

    PubMed Central

    2014-01-01

    Background Magnetic resonance imaging (MRI) allows detailed study of structural and functional changes in the brain in patients with cerebral malaria. Methods In a prospective observational study in adult Bangladeshi patients with severe falciparum malaria, MRI findings in the brain were correlated with clinical and laboratory parameters, retinal photography and optic nerve sheath diameter (ONSD) ultrasound (a marker of intracranial pressure). Results Of 43 enrolled patients, 31 (72%) had coma and 12 (28%) died. MRI abnormalities were present in 79% overall with mostly mild changes in a wide range of anatomical sites. There were no differences in MRI findings between patients with cerebral and non-cerebral or fatal and non-fatal disease. Subtle diffuse cerebral swelling was common (n = 22/43), but mostly without vasogenic oedema or raised intracranial pressure (ONSD). Also seen were focal extracellular oedema (n = 11/43), cytotoxic oedema (n = 8/23) and mildly raised brain lactate on magnetic resonance spectroscopy (n = 5/14). Abnormalities were much less prominent than previously described in Malawian children. Retinal whitening was present in 36/43 (84%) patients and was more common and severe in patients with coma. Conclusion Cerebral swelling is mild and not specific to coma or death in adult severe falciparum malaria. This differs markedly from African children. Retinal whitening, reflecting heterogeneous obstruction of the central nervous system microcirculation by sequestered parasites resulting in small patches of ischemia, is associated with coma and this process is likely important in the pathogenesis. PMID:24884982

  3. Clinical Efficacy of Dihydroartemisinin-Piperaquine for the Treatment of Uncomplicated Plasmodium falciparum Malaria at the China-Myanmar Border.

    PubMed

    Wang, Ying; Yang, Zhaoqing; Yuan, Lili; Zhou, Guofa; Parker, Daniel; Lee, Ming-Chieh; Yan, Guiyun; Fan, Qi; Xiao, Yuping; Cao, Yaming; Cui, Liwang

    2015-09-01

    Artemisinin-based combination therapies (ACTs) are currently used as the first-line therapy for uncomplicated Plasmodium falciparum malaria. However, the recent emergence and/or spread of artemisinin resistance in parts of Greater Mekong Subregion (GMS) of southeast Asia requires close monitoring of the therapeutic efficacy of ACTs. This study was conducted from March 2012 to December 2013 in four clinics and seven villages along the China-Myanmar border. A total of 109 patients with uncomplicated falciparum malaria were treated with dihydroartemisinin-piperaquine (DP) and followed up on days 1, 2, 3, 7, 14, 21, 28, and 42 after treatment. A total of 71 patients (22 children and 49 adults) completed the 42-day follow-up. DP remained highly efficacious for treatment of uncomplicated falciparum malaria with an overall 42-day cure rate of 100%. The day 3 parasite-positive rate was 7.04% (5/71). Within 14 days of treatment, a total of 13 (18.31%) patients had detectable gametocytes and a large proportion of these were persistent from the first three days of treatment. The presence of gametocytes in patients through 14 days after DP treatment suggests that the incorporation of a single dose of primaquine for clearing gametocytemia should be considered for blocking parasite transmission. PMID:26283743

  4. Clinical Efficacy of Dihydroartemisinin–Piperaquine for the Treatment of Uncomplicated Plasmodium falciparum Malaria at the China–Myanmar Border

    PubMed Central

    Wang, Ying; Yang, Zhaoqing; Yuan, Lili; Zhou, Guofa; Parker, Daniel; Lee, Ming-Chieh; Yan, Guiyun; Fan, Qi; Xiao, Yuping; Cao, Yaming; Cui, Liwang

    2015-01-01

    Artemisinin-based combination therapies (ACTs) are currently used as the first-line therapy for uncomplicated Plasmodium falciparum malaria. However, the recent emergence and/or spread of artemisinin resistance in parts of Greater Mekong Subregion (GMS) of southeast Asia requires close monitoring of the therapeutic efficacy of ACTs. This study was conducted from March 2012 to December 2013 in four clinics and seven villages along the China–Myanmar border. A total of 109 patients with uncomplicated falciparum malaria were treated with dihydroartemisinin–piperaquine (DP) and followed up on days 1, 2, 3, 7, 14, 21, 28, and 42 after treatment. A total of 71 patients (22 children and 49 adults) completed the 42-day follow-up. DP remained highly efficacious for treatment of uncomplicated falciparum malaria with an overall 42-day cure rate of 100%. The day 3 parasite-positive rate was 7.04% (5/71). Within 14 days of treatment, a total of 13 (18.31%) patients had detectable gametocytes and a large proportion of these were persistent from the first three days of treatment. The presence of gametocytes in patients through 14 days after DP treatment suggests that the incorporation of a single dose of primaquine for clearing gametocytemia should be considered for blocking parasite transmission. PMID:26283743

  5. Relative Susceptibilities of ABO Blood Groups to Plasmodium falciparum Malaria in Ghana

    PubMed Central

    Afoakwah, Richmond; Aubyn, Edmond; Prah, James; Nwaefuna, Ekene Kwabena; Boampong, Johnson N.

    2016-01-01

    The clinical outcome of falciparum malaria in endemic areas is influenced by erythrocyte polymorphisms including the ABO blood groups. Studies have reported association of ABO blood group to resistance, susceptibility, and severity of P. falciparum malaria infection. Individuals with blood group “A” have been found to be highly susceptible to falciparum malaria whereas blood group “O” is said to confer protection against complicated cases. We analyzed samples from 293 young children less than six years old with malaria in the Korle-Bu Teaching Hospital in Accra, Ghana. It was observed that group O was present in about 16.1% of complicated cases weighed against 40.9% of uncomplicated controls. Individuals with complicated malaria were about twice likely to be of blood groups A and B compared to group O (A versus O, OR = 1.90, 95% CI = 1.59–2.26, P < 0.0001; B versus O, OR = 1.82. 95% CI = 1.57–2.23, P < 0.0001). Blood group O participants with complicated diseases had low parasitaemia compared to the other blood groups (P < 0.0001). This may give blood group O individuals a survival advantage over the other groups in complicated malaria as suggested. Participants with complicated falciparum malaria were generally anaemic and younger than those with uncomplicated disease. PMID:26981125

  6. Asymmetric Dimethylarginine in Adult Falciparum Malaria: Relationships With Disease Severity, Antimalarial Treatment, Hemolysis, and Inflammation

    PubMed Central

    Barber, Bridget E.; William, Timothy; Grigg, Matthew J.; Parameswaran, Uma; Piera, Kim A.; Yeo, Tsin W.; Anstey, Nicholas M.

    2016-01-01

    Background. Endothelial nitric oxide (NO) bioavailability is impaired in severe falciparum malaria (SM). Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase (NOS), contributes to endothelial dysfunction and is associated with mortality in adults with falciparum malaria. However, factors associated with ADMA in malaria, including the NOS-substrate l-arginine, hemolysis, and antimalarial treatment, are not well understood. Methods. In a prospective observational study of Malaysian adults with SM (N = 22) and non-SM (NSM; N = 124) and healthy controls (HCs), we investigated factors associated with plasma ADMA including the effects of antimalarial treatment. Results. Compared with HCs, ADMA levels were lower in NSM (0.488 µM vs 0.540 µM, P = .001) and in the subset of SM patients enrolled before commencing treatment (0.453 µM [N = 5], P = .068), but levels were higher in SM patients enrolled after commencing antimalarial treatment (0.610 µM [N = 17], P = .026). In SM and NSM, ADMA levels increased significantly to above-baseline levels by day 3. Baseline ADMA was correlated with arginine and cell-free hemoglobin in SM and NSM and inversely correlated with interleukin-10 in NSM. Arginine and the arginine/ADMA ratio (reflective of arginine bioavailability) were lower in SM and NSM compared with HCs, and the arginine/ADMA ratio was lower in SM compared with NSM. Conclusions. Pretreatment ADMA concentrations and l-arginine bioavailability are reduced in SM and NSM. Asymmetric dimethylarginine increases to above-baseline levels after commencement of antimalarial treatment. Arginine, hemolysis, and posttreatment inflammation all likely contribute to ADMA regulation, with ADMA likely contributing to the reduced NO bioavailability in SM. PMID:26985445

  7. Impaired nitric oxide bioavailability and L-arginine reversible endothelial dysfunction in adults with falciparum malaria.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Gitawati, Retno; Tjitra, Emiliana; Kenangalem, Enny; McNeil, Yvette R; Darcy, Christabelle J; Granger, Donald L; Weinberg, J Brice; Lopansri, Bert K; Price, Ric N; Duffull, Stephen B; Celermajer, David S; Anstey, Nicholas M

    2007-10-29

    Severe falciparum malaria (SM) is associated with tissue ischemia related to cytoadherence of parasitized erythrocytes to microvascular endothelium and reduced levels of NO and its precursor, l-arginine. Endothelial function has not been characterized in SM but can be improved by l-arginine in cardiovascular disease. In an observational study in Indonesia, we measured endothelial function using reactive hyperemia-peripheral arterial tonometry (RH-PAT) in 51 adults with SM, 48 patients with moderately severe falciparum malaria (MSM), and 48 controls. The mean RH-PAT index was lower in SM (1.41; 95% confidence interval [CI] = 1.33-1.47) than in MSM (1.82; 95% CI = 1.7-2.02) and controls (1.93; 95% CI = 1.8-2.06; P < 0.0001). Endothelial dysfunction was associated with elevated blood lactate and measures of hemolysis. Exhaled NO was also lower in SM relative to MSM and controls. In an ascending dose study of intravenous l-arginine in 30 more patients with MSM, l-arginine increased the RH-PAT index by 19% (95% CI = 6-34; P = 0.006) and exhaled NO by 55% (95% CI = 32-73; P < 0.0001) without important side effects. Hypoargininemia and hemolysis likely reduce NO bioavailability. Endothelial dysfunction in malaria is nearly universal in severe disease, is reversible with l-arginine, and likely contributes to its pathogenesis. Clinical trials in SM of adjunctive agents to improve endothelial NO bioavailability, including l-arginine, are warranted.

  8. Asymmetric Dimethylarginine in Adult Falciparum Malaria: Relationships With Disease Severity, Antimalarial Treatment, Hemolysis, and Inflammation.

    PubMed

    Barber, Bridget E; William, Timothy; Grigg, Matthew J; Parameswaran, Uma; Piera, Kim A; Yeo, Tsin W; Anstey, Nicholas M

    2016-01-01

    Background.  Endothelial nitric oxide (NO) bioavailability is impaired in severe falciparum malaria (SM). Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase (NOS), contributes to endothelial dysfunction and is associated with mortality in adults with falciparum malaria. However, factors associated with ADMA in malaria, including the NOS-substrate l-arginine, hemolysis, and antimalarial treatment, are not well understood. Methods.  In a prospective observational study of Malaysian adults with SM (N = 22) and non-SM (NSM; N = 124) and healthy controls (HCs), we investigated factors associated with plasma ADMA including the effects of antimalarial treatment. Results.  Compared with HCs, ADMA levels were lower in NSM (0.488 µM vs 0.540 µM, P = .001) and in the subset of SM patients enrolled before commencing treatment (0.453 µM [N = 5], P = .068), but levels were higher in SM patients enrolled after commencing antimalarial treatment (0.610 µM [N = 17], P = .026). In SM and NSM, ADMA levels increased significantly to above-baseline levels by day 3. Baseline ADMA was correlated with arginine and cell-free hemoglobin in SM and NSM and inversely correlated with interleukin-10 in NSM. Arginine and the arginine/ADMA ratio (reflective of arginine bioavailability) were lower in SM and NSM compared with HCs, and the arginine/ADMA ratio was lower in SM compared with NSM. Conclusions.  Pretreatment ADMA concentrations and l-arginine bioavailability are reduced in SM and NSM. Asymmetric dimethylarginine increases to above-baseline levels after commencement of antimalarial treatment. Arginine, hemolysis, and posttreatment inflammation all likely contribute to ADMA regulation, with ADMA likely contributing to the reduced NO bioavailability in SM.

  9. Artemether-Lumefantrine Compared to Atovaquone-Proguanil as a Treatment for Uncomplicated Plasmodium falciparum Malaria in Travelers

    PubMed Central

    Grynberg, Shirly; Lachish, Tamar; Kopel, Eran; Meltzer, Eyal; Schwartz, Eli

    2015-01-01

    Atovaquone-proguanil (AP) and artemether-lumefantrine (AL) are both treatments for uncomplicated Plasmodium falciparum malaria, but comparative clinical trials are lacking. We performed a retrospective analysis, comparing treatment failure and fever clearance time in non-immune travelers with uncomplicated P. falciparum malaria, treated with AP or AL. Sixty-nine patients were included during 2001–2013: 44 in the AP group and 25 in the AL group. Treatment failure was observed in 6 of 44 (13.6%) and 1 of 25 (4.0%) patients in the AP and AL groups, respectively. Six treatment failures were observed in travelers from West Africa. Fever clearance time was 44 ± 23 h in AL group versus 77 ± 28 h in AP group, (P < 0.001). Hospitalization time was significantly shorter in the AL group; 3.8 + 1.3 versus 5.1 + 2.8 days in the AP group (P = 0.04) In conclusion, travelers with uncomplicated P. falciparum malaria recover faster on AL than on AP. The AL should probably be the drug of choice for this population. PMID:25371188

  10. Cost-effectiveness analysis of artesunate and quinine + tetracycline for the treatment of uncomplicated falciparum malaria in Chanthaburi, Thailand.

    PubMed Central

    Honrado, E. R.; Fungladda, W.; Kamoiratanaku, P.; Kitayaporn, D.; Karbwang, J.; Thimasarn, K.; Masngammueng, R.

    1999-01-01

    A randomized, controlled, malaria-clinic-based field trial was carried out to compare the cost-effectiveness of a 5-day 700-mg oral artesunate and a 7-day quinine + tetracycline regimen for the treatment of uncomplicated falciparum malaria in Thailand. Cost-effectiveness was determined from the providers' perspective and based on curative effectiveness. A total of 137 patients, aged 15-60 years, attending a malaria clinic were followed for 28 days, 60 of them received quinine + tetracycline and 77 received artesunate. Cure rates were assessed on day 5 (artesunate) and day 7 (quinine + tetracycline), using the intention-to-treat approach. Cost-effectiveness and sensitivity analyses were performed by varying the day 5/day 7 curative effectiveness and cost of artesunate. The cure rate with artesunate (100%) was significantly higher than with quinine + tetracycline (77.4%) (relative risk adjusted for sex (aRR) = 1.32, 95% confidence interval (CI) = 1.12-1.55; referent quinine + tetracycline). Artesunate was more cost-effective than quinine + tetracycline at the following costs: artesunate, < or = US$0.36 per 50-mg tablet; quinine, US$0.06 per 300-mg tablet; tetracycline, US$0.02 per 250-mg capsule; and services per case found, < or = US$11.49. Because of the higher cure rate and higher cost-effectiveness of the artesunate regimen compared with quinine + tetracycline, we recommend its use for the treatment of uncomplicated falciparum malaria in malaria clinics in Thailand. PMID:10212514

  11. Dynamics of Plasmodium falciparum Parasitemia Regarding Combined Treatment Regimens for Acute Uncomplicated Malaria, Antioquia, Colombia

    PubMed Central

    Álvarez, Gonzalo; Tobón, Alberto; Piñeros, Juan-Gabriel; Ríos, Alexandra; Blair, Silvia

    2010-01-01

    Selecting suitable anti-malarial treatment represents one of the best tools for reducing morbidity and mortality caused by this disease. Sexual and asexual parasite dynamics were thus evaluated in patients involved in antimalarial drug efficacy studies by using combined treatment with and without artemisinin derivatives for treating uncomplicated acute Plasmodium falciparum malaria in Antioquia, Colombia. All treatment doses were supervised and administered according to patients' weight; sexual and asexual parasitemia were evaluated during 28- or 42-days follow-up in 468 patients. Artemisinin-based combination therapy showed greater parasiticidal ability, showing a mean asexual parasitemia survival rate of one day and mean gametocyte survival rate of 1–2 days. Sexual and asexual parasitemias were eliminated more quickly and effectively in the group receiving artemisinin-based combination therapy. Adding 45 mg of primaquine to treatment with artesunate and mefloquine reduced gametocyte and asexual parasite survival by one day. PMID:20595483

  12. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria

    NASA Astrophysics Data System (ADS)

    Ariey, Frédéric; Witkowski, Benoit; Amaratunga, Chanaki; Beghain, Johann; Langlois, Anne-Claire; Khim, Nimol; Kim, Saorin; Duru, Valentine; Bouchier, Christiane; Ma, Laurence; Lim, Pharath; Leang, Rithea; Duong, Socheat; Sreng, Sokunthea; Suon, Seila; Chuor, Char Meng; Bout, Denis Mey; Ménard, Sandie; Rogers, William O.; Genton, Blaise; Fandeur, Thierry; Miotto, Olivo; Ringwald, Pascal; Le Bras, Jacques; Berry, Antoine; Barale, Jean-Christophe; Fairhurst, Rick M.; Benoit-Vical, Françoise; Mercereau-Puijalon, Odile; Ménard, Didier

    2014-01-01

    Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain (`K13-propeller') with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread.

  13. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria

    PubMed Central

    Ariey, Frédéric; Witkowski, Benoit; Amaratunga, Chanaki; Beghain, Johann; Langlois, Anne-Claire; Khim, Nimol; Kim, Saorin; Duru, Valentine; Bouchier, Christiane; Ma, Laurence; Lim, Pharath; Leang, Rithea; Duong, Socheat; Sreng, Sokunthea; Suon, Seila; Chuor, Char Meng; Bout, Denis Mey; Ménard, Sandie; Rogers, William O.; Genton, Blaise; Fandeur, Thierry; Miotto, Olivo; Ringwald, Pascal; Le Bras, Jacques; Berry, Antoine; Barale, Jean-Christophe; Fairhurst, Rick M.; Benoit-Vical, Françoise; Mercereau-Puijalon, Odile; Ménard, Didier

    2016-01-01

    Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain (‘K13-propeller’) with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread. PMID:24352242

  14. Haplotypes associated with resistance to sulfadoxine-pyrimethamine in Plasmodium falciparum in two malaria endemic locations in Colombia.

    PubMed

    Hernández, Diana Carolina; Guerra, Angela Patricia; Cucunubá, Zulma Milena; Nicholls, Ruben Santiago; Barrera, Sandra Milena

    2013-08-01

    Colombia has four main malaria transmission zones. In vivo efficacy studies carried out in these areas showed big differences in the response of Plasmodium falciparum to treatment with sulphadoxine-pyrimethamine. In addition, there is still insufficient information about the genetics of P. falciparum populations. The objective of this study was to determine the haplotypes in dhfr and dhps genes of P. falciparum circulating in two distinct endemic zones. Samples from patients with non-complicated P. falciparum malaria were collected: 135 from Tumaco and 206 from Tierralta. Alleles 108 and 51 of the dhfr gene, and 437 and 540 of the dhps gene were analyzed by PCR/enzymatic restriction, while alleles 59 and 164 (dhfr), and 581(dhps) by PCR/dot blot/hybridization. Five different haplotypes were found, of which the triple mutant 51I/C59/108N/I164/437G/K540/A581 was the most frequent (54.6%). In Tumaco, the parasites with wild haplotype predominated, while mutant parasites predominated in Tierralta. Another interesting finding is the presence of the C59R mutation in the dhfr gene in two samples, a mutation rarely found in South America. These data provide information about parasite population genetics and highlight the importance of starting a long term molecular surveillance program. PMID:23714094

  15. Trend and manifestations of falciparum malaria in a tertiary care hospital of India

    PubMed Central

    Saya, Rama Prakasha; Saya, Ganesh Kumar; Debabrata, Goswami

    2016-01-01

    Background: The recent focus is on the increase in the burden of falciparum cases with a varied spectrum of presentation and outcome, especially in developing countries like India. This study was undertaken to analyze the trend and manifestations of falciparum malaria in a tertiary care hospital. Materials and Methods: This descriptive study was carried out at the Gauhati Government Medical College and Hospital from June 2006 to May 2007. The data were collected on demographic and time characteristics, clinical and laboratory findings, the outcome of disease and expressed in proportion or percentages. Results: Out of the 100 cases, around 2nd/3rd (63%) of cases were in the age group of 15–30 years and the mean age was found to be 29.51 years. About 66% of them were males. Clinical presentations included pain abdomen (42, 42%), nausea and vomiting (35, 35%), jaundice (34, 34%), oliguria (24, 24%), altered sensorium (24, 24%), breathing difficulty (10, 10%), and seizures (5, 5%). Number of cases and mortality were more with a peak in the month of May and September. Manifestations of severe falciparum malaria included hepatopathy (38%), renal failure (28%), shock (9%), acute respiratory distress syndrome (7%), hypoglycemia (3%), and severe anemia (1%). Eighty-two cases (82%) recovered and 18 cases (18%) expired. Conclusion: Falciparum malaria is more among younger adult age group and males. Complications and mortality are also more due to falciparum malaria. PMID:27563638

  16. Estimating the Global Clinical Burden of Plasmodium falciparum Malaria in 2007

    PubMed Central

    Hay, Simon I.; Okiro, Emelda A.; Gething, Peter W.; Patil, Anand P.; Tatem, Andrew J.; Guerra, Carlos A.; Snow, Robert W.

    2010-01-01

    Background The epidemiology of malaria makes surveillance-based methods of estimating its disease burden problematic. Cartographic approaches have provided alternative malaria burden estimates, but there remains widespread misunderstanding about their derivation and fidelity. The aims of this study are to present a new cartographic technique and its application for deriving global clinical burden estimates of Plasmodium falciparum malaria for 2007, and to compare these estimates and their likely precision with those derived under existing surveillance-based approaches. Methods and Findings In seven of the 87 countries endemic for P. falciparum malaria, the health reporting infrastructure was deemed sufficiently rigorous for case reports to be used verbatim. In the remaining countries, the mapped extent of unstable and stable P. falciparum malaria transmission was first determined. Estimates of the plausible incidence range of clinical cases were then calculated within the spatial limits of unstable transmission. A modelled relationship between clinical incidence and prevalence was used, together with new maps of P. falciparum malaria endemicity, to estimate incidence in areas of stable transmission, and geostatistical joint simulation was used to quantify uncertainty in these estimates at national, regional, and global scales. Combining these estimates for all areas of transmission risk resulted in 451 million (95% credible interval 349–552 million) clinical cases of P. falciparum malaria in 2007. Almost all of this burden of morbidity occurred in areas of stable transmission. More than half of all estimated P. falciparum clinical cases and associated uncertainty occurred in India, Nigeria, the Democratic Republic of the Congo (DRC), and Myanmar (Burma), where 1.405 billion people are at risk. Recent surveillance-based methods of burden estimation were then reviewed and discrepancies in national estimates explored. When these cartographically derived national

  17. Association of severe malaria with a specific Plasmodium falciparum genotype in French Guiana.

    PubMed

    Ariey, F; Hommel, D; Le Scanf, C; Duchemin, J B; Peneau, C; Hulin, A; Sarthou, J L; Reynes, J M; Fandeur, T; Mercereau-Puijalon, O

    2001-07-15

    Why severe Plasmodium falciparum malaria occurs in only a small percentage of patients is unclear. The possibility that specific parasite characteristics contribute to severity has been investigated in French Guiana, a hypoendemic area, where parasite diversity is low and all patients with severe cases are referred to a single intensive care unit. Parasite genotyping in geographically and temporally matched patients with mild and severe disease showed that the association of a specific msp-1 allele (B-K1) with a specific var gene (var-D) was overrepresented among patients with severe versus mild disease (47% vs. 3%, respectively; P<.001). Moreover, this genotype combination was consistently observed in the most severe clinical cases. Reverse-transcription polymerase chain reaction demonstrated programmed expression of var-D in vivo, which is consistent with its potential implication in severe disease. These results provide field evidence of an association of severe malaria with specific genetic characteristics of parasites and open the way for intervention strategies targeting key virulence factors of parasites.

  18. Chloroquine resistant Plasmodium falciparum malaria in Osogbo Nigeria: efficacy of amodiaquine + sulfadoxine-pyrimethamine and chloroquine + chlorpheniramine for treatment.

    PubMed

    Ogungbamigbe, T O; Ojurongbe, O; Ogunro, P S; Okanlawon, B M; Kolawole, S O

    2008-02-01

    Chloroquine (CQ) resistance in Plasmodium falciparum contributes to increasing malaria-attributable morbidity and mortality in Sub-Saharan Africa. Despite a change in drug policy, continued prescription of CQ did not abate. Therefore the therapeutic efficacy of CQ in uncomplicated falciparum malaria patients was assessed in a standard 28-day protocol in 116 children aged between six and 120 months in Osogbo, Southwest Nigeria. Parasitological and clinical assessments of response to treatment showed that 72 (62.1%) of the patients were cured and 44 (37.9%) failed the CQ treatment. High initial parasite density and young age were independent predictors for early treatment failure. Out of the 44 patients that failed CQ, 24 received amodiaquine + sulphadoxine/pyrimethamine (AQ+SP) and 20 received chlorpheniramine + chloroquine (CH+CQ) combinations. Mean fever clearance time in those treated with AQ+SP was not significantly different from those treated with CH+CQ (p = 0.05). There was no significant difference in the mean parasite density of the two groups. The cure rate for AQ+SP group was 92% while those of CH+CQ was 85%. There was a significant difference in parasite clearance time (p = 0.01) between the two groups. The 38% treatment failure for CQ reported in this study is higher than the 10% recommended by World Health Organization in other to effect change in antimalarial treatment policy. Hence we conclude that CQ can no more be solely relied upon for the treatment of falciparum malaria in Osogbo, Nigeria. AQ+SP and CH+CQ are effective in the treatment of acute uncomplicated malaria and may be considered as useful alternative drugs in the absence of artemisinin-based combination therapies.

  19. Safety of falciparum malaria diagnostic strategy based on rapid diagnostic tests in returning travellers and migrants: a retrospective study

    PubMed Central

    2012-01-01

    Background Rapid diagnostic tests for malaria (RDTs) allow accurate diagnosis and prompt treatment. Validation of their usefulness in travellers with fever was needed. The safety of a strategy to diagnose falciparum malaria based on RDT followed by immediate or delayed microscopy reading at first attendance was evaluated in one referral hospital in Switzerland. Methods A retrospective study was conducted in the outpatient clinic and emergency ward of University Hospital, covering a period of eight years (1999–2007). The study was conducted in the outpatient clinic and emergency ward of University Hospital. All adults suspected of malaria with a diagnostic test performed were included. RDT and microscopy as immediate tests were performed during working hours, and RDT as immediate test and delayed microscopy reading out of laboratory working hours. The main outcome measure was occurrence of specific complications in RDT negative and RDT positive adults. Results 2,139 patients were recruited. 1987 had both initial RDT and blood smear (BS) result negative. Among those, 2/1987 (0.1%) developed uncomplicated malaria with both RDT and BS positive on day 1 and day 6 respectively. Among the 152 patients initially malaria positive, 137 had both RDT and BS positive, four only BS positive and five only RDT positive (PCR confirmed) (six had only one test performed). None of the four initially RDT negative/BS positive and none of the five initially BS negative/RDT positive developed severe malaria while 6/137 of both RDT and BS positive did so. The use of RDT allowed a reduction of a median of 2.1 hours to get a first malaria test result. Conclusions A malaria diagnostic strategy based on RDTs and a delayed BS is safe in non-immune populations, and shortens the time to first malaria test result. PMID:23158019

  20. Increasing Plasmodium falciparum malaria in southwest London: a 25 year observational study

    PubMed Central

    Williams, J; Chitre, M; Sharland, M

    2002-01-01

    Aims: To identify changes in the presenting number and species of imported malaria in children in southwest London. Methods: A prospective single observer study over 25 years (1975–99) of all cases of paediatric malaria seen at St George's Hospital. Results: A confirmed diagnosis was made in 249 children (56% boys; 44% girls; median age 8.0 years). Of these, 53% were UK residents and 44% were children travelling to the UK. A significant increase was noted in the number of cases over the 25 years (1975–79: mean 4.8 cases/year; 1990–99: mean 13.7 cases/year). Over the 25 years Plasmodium falciparum was seen in 77%, P vivax in 14%, P ovale in 6%, and P malariae in 3% of cases. P falciparum had increased in frequency (1975–79: P falciparum 50%, P vivax 50%; 1990–99: P falciparum 82%, P vivax 6%), associated with an increase in the proportion of children acquiring their infection in sub-Saharan Africa. Median time between arrival in the UK to the onset of fever was: P falciparum, 5 days; P ovale, 25 days; P malariae, 37 days; and P vivax, 62 days. Median time interval between the onset of fever to commencement of treatment was 4 days. This had not improved over the 25 year period. Only 41% of UK resident children presenting to hospital had taken prophylaxis and the overall number of symptomatic children taking no prophylaxis was increasing. Conclusion: Imported childhood P falciparum malaria is increasing in southwest London associated with increasing travel from sub-Saharan Africa. Over the 25 year period there has been no improvement in chemoprophylaxis rates or time to diagnosis. PMID:12023177

  1. Population genetics of Plasmodium falciparum and Plasmodium vivax and asymptomatic malaria in Temotu Province, Solomon Islands

    PubMed Central

    2013-01-01

    Background Temotu Province, Solomon Islands is progressing toward malaria elimination. A baseline survey conducted in 2008 showed that most Plasmodium infections in the province were of low parasite density and asymptomatic infections. To better understand mechanisms underlying these malaria transmission characteristics genetic diversity and relationships among Plasmodium falciparum and Plasmodium vivax populations in the province were examined. Methods Forty-five P. falciparum and 67 P. vivax samples collected in the 2008 baseline survey were successfully genotyped using eight P. falciparum and seven P. vivax microsatellite markers. Genetic diversity, relationships and distribution of both P. falciparum and P. vivax populations were analysed. Results Plasmodium falciparum population exhibited low diversity with 19 haplotypes identified and had closely related clusters indicating clonal expansion. Interestingly, a dominant haplotype was significantly associated with fever and high parasite density. In contrast, the P. vivax population was highly diverse with 58 haplotypes identified that were not closely related. Parasite populations between different islands in the province showed low genetic differentiation. Conclusion The low diversity and clonal population of P. falciparum population may partially account for clinical immunity developed against illness. However, it is possible that importation of a new P. falciparum strain was the major cause of illness. High diversity in P. vivax population and low relatedness between strains suggested clinical immunity to P. vivax may be maintained by different mechanisms. The genetic diversity, population structure and distribution of strains indicate that transmission of P. falciparum was low, but that of P. vivax was still high in 2008. These data will be useful for assessing changes in malaria transmission resulting from interventions. PMID:24261646

  2. Malaria morbidity in Papua Indonesia, an area with multidrug resistant Plasmodium vivax and Plasmodium falciparum

    PubMed Central

    Karyana, Muhammad; Burdarm, Lenny; Yeung, Shunmay; Kenangalem, Enny; Wariker, Noah; Maristela, Rilia; Umana, Ketut Gde; Vemuri, Ram; Okoseray, Maurits J; Penttinen, Pasi M; Ebsworth, Peter; Sugiarto, Paulus; Anstey, Nicholas M; Tjitra, Emiliana; Price, Richard N

    2008-01-01

    Background Multidrug resistance has emerged to both Plasmodium vivax and Plasmodium falciparum and yet the comparative epidemiology of these infections is poorly defined. Methods All laboratory-confirmed episodes of malaria in Timika, Papua, Indonesia, presenting to community primary care clinics and an inpatient facility were reviewed over a two-year period. In addition information was gathered from a house-to-house survey to quantify the prevalence of malaria and treatment-seeking behaviour of people with fever. Results Between January 2004 and December 2005, 99,158 laboratory-confirmed episodes of malaria were reported, of which 58% (57,938) were attributable to P. falciparum and 37% (36,471) to P. vivax. Malaria was most likely to be attributable to pure P. vivax in children under one year of age (55% 2,684/4,889). In the household survey, the prevalence of asexual parasitaemia was 7.5% (290/3,890) for P. falciparum and 6.4% (248/3,890) for P. vivax. The prevalence of P. falciparum infection peaked in young adults aged 15–25 years (9.8% 69/707), compared to P. vivax infection which peaked in children aged 1 to 4 years (9.5% 61/642). Overall 35% (1,813/5,255) of people questioned reported a febrile episode in the preceding month. Of the 60% of people who were estimated to have had malaria, only 39% would have been detected by the surveillance network. The overall incidence of malaria was therefore estimated as 876 per 1,000 per year (Range: 711–906). Conclusion In this region of multidrug-resistant P. vivax and P. falciparum, both species are associated with substantial morbidity, but with significant differences in the age-related risk of infection. PMID:18673572

  3. Falciparum malaria and climate change in the northwest frontier province of Pakistan.

    PubMed

    Bouma, M J; Dye, C; van der Kaay, H J

    1996-08-01

    Following a striking increase in the severity of autumnal outbreaks of Plasmodium falciparum during the last decade in the Northwest Frontier Province (NWFP) of Pakistan, the role of climatologic variables was investigated. A multivariate analysis showed that during the transmission season of P. falciparum, the amount of rainfall in September and October, the temperature in November and December, and the humidity in December were all correlated (r2 = 0.82) with two measures of P. falciparum, the falciparum rate (percent of slides examined positive for P. falciparum) since 1981 and the annual P. falciparum proportion (percent of all malaria infections diagnosed as P. falciparum) since 1978. Climatologic records since 1876 show an increase in mean November and December temperatures by 2 degrees C and 1.5 degrees C, respectively, and in October rainfall. Mean humidity in December has also been increasing since 1950. These climatologic changes in the area appear to have made conditions for transmission of P. falciparum more favorable, and may account for the increase in incidence observed in the NWFP in recent years.

  4. Loop-mediated isothermal PCR (LAMP) for the diagnosis of falciparum malaria.

    PubMed

    Paris, Daniel H; Imwong, Mallika; Faiz, Abul M; Hasan, Mahtabuddin; Yunus, Emran Bin; Silamut, Kamolrat; Lee, Sue J; Day, Nicholas P J; Dondorp, Arjen M

    2007-11-01

    A recently described loop-mediated isothermal polymerase chain reaction (LAMP) for molecular detection of Plasmodium falciparum was compared with microscopy, PfHRP2-based rapid diagnostic test (RDT), and nested polymerase chain reaction (PCR) as the "gold standard" in 115 Bangladeshi in-patients with fever. DNA extraction for LAMP was conducted by conventional methods or simple heating of the sample; test results were either assessed visually or by gel electrophoresis. Conventional DNA extraction followed by gel electrophoresis had the highest agreement with the reference method (81.7%, kappa = 0.64), with a sensitivity (95% CI) of 76.1% (68.3-83.9%), comparable to RDT and microscopy, but a specificity of 89.6% (84.0-95.2%) compared with 100% for RDT and microscopy. DNA extraction by heat treatment deteriorated specificity to unacceptable levels. LAMP enables molecular diagnosis of falciparum malaria in settings with limited technical resources but will need further optimization. The results are in contrast with a higher accuracy reported in an earlier study comparing LAMP with a non-validated PCR method.

  5. Insights into the pyrimidine biosynthetic pathway of human malaria parasite Plasmodium falciparum as chemotherapeutic target.

    PubMed

    Krungkrai, Sudaratana R; Krungkrai, Jerapan

    2016-06-01

    Malaria is a major cause of morbidity and mortality in humans. Artemisinins remain as the first-line treatment for Plasmodium falciparum (P. falciparum) malaria although drug resistance has already emerged and spread in Southeast Asia. Thus, to fight this disease, there is an urgent need to develop new antimalarial drugs for malaria chemotherapy. Unlike human host cells, P. falciparum cannot salvage preformed pyrimidine bases or nucleosides from the extracellular environment and relies solely on nucleotides synthesized through the de novo biosynthetic pathway. This review presents significant progress on understanding the de novo pyrimidine pathway and the functional enzymes in the human parasite P. falciparum. Current knowledge in genomics and metabolomics are described, particularly focusing on the parasite purine and pyrimidine nucleotide metabolism. These include gene annotation, characterization and molecular mechanism of the enzymes that are different from the human host pathway. Recent elucidation of the three-dimensional crystal structures and the catalytic reactions of three enzymes: dihydroorotate dehydrogenase, orotate phosphoribosyltransferase, and orotidine 5'-monophosphate decarboxylase, as well as their inhibitors are reviewed in the context of their therapeutic potential against malaria. PMID:27262062

  6. Insights into the pyrimidine biosynthetic pathway of human malaria parasite Plasmodium falciparum as chemotherapeutic target.

    PubMed

    Krungkrai, Sudaratana R; Krungkrai, Jerapan

    2016-06-01

    Malaria is a major cause of morbidity and mortality in humans. Artemisinins remain as the first-line treatment for Plasmodium falciparum (P. falciparum) malaria although drug resistance has already emerged and spread in Southeast Asia. Thus, to fight this disease, there is an urgent need to develop new antimalarial drugs for malaria chemotherapy. Unlike human host cells, P. falciparum cannot salvage preformed pyrimidine bases or nucleosides from the extracellular environment and relies solely on nucleotides synthesized through the de novo biosynthetic pathway. This review presents significant progress on understanding the de novo pyrimidine pathway and the functional enzymes in the human parasite P. falciparum. Current knowledge in genomics and metabolomics are described, particularly focusing on the parasite purine and pyrimidine nucleotide metabolism. These include gene annotation, characterization and molecular mechanism of the enzymes that are different from the human host pathway. Recent elucidation of the three-dimensional crystal structures and the catalytic reactions of three enzymes: dihydroorotate dehydrogenase, orotate phosphoribosyltransferase, and orotidine 5'-monophosphate decarboxylase, as well as their inhibitors are reviewed in the context of their therapeutic potential against malaria.

  7. A non-pharmaceutical form of Artemisia annua is not effective in preventing Plasmodium falciparum malaria.

    PubMed

    Lagarce, Laurence; Lerolle, Nicolas; Asfar, Pierre; Le Govic, Yohann; Lainé-Cessac, Pascale; de Gentile, Ludovic

    2016-05-01

    Non-pharmaceutical forms of Artemisia annua (a Chinese plant containing artemisinin) are used by some travellers who believe these products are safer than anti-malarial drugs. We report two cases of severe Plasmodium falciparum malaria requiring hospitalization in an Intensive Care Unit following prophylaxis with non-pharmaceutical A. annua in French travellers.

  8. Slow Clearance of Plasmodium falciparum in Severe Pediatric Malaria, Uganda, 2011-2013.

    PubMed

    Hawkes, Michael; Conroy, Andrea L; Opoka, Robert O; Namasopo, Sophie; Zhong, Kathleen; Liles, W Conrad; John, Chandy C; Kain, Kevin C

    2015-07-01

    Plasmodium falciparum resistance to artemisinin derivatives is emerging in Asia. We examined molecular markers of resistance in 78 children in Uganda who had severe malaria and were treated with intravenous artesunate. We observed in the K13-propeller domain, A578S, a low-frequency (3/78), nonsynonymous, single-nucleotide polymorphism associated with prolonged parasite clearance.

  9. Slow Clearance of Plasmodium falciparum in Severe Pediatric Malaria, Uganda, 2011-2013.

    PubMed

    Hawkes, Michael; Conroy, Andrea L; Opoka, Robert O; Namasopo, Sophie; Zhong, Kathleen; Liles, W Conrad; John, Chandy C; Kain, Kevin C

    2015-07-01

    Plasmodium falciparum resistance to artemisinin derivatives is emerging in Asia. We examined molecular markers of resistance in 78 children in Uganda who had severe malaria and were treated with intravenous artesunate. We observed in the K13-propeller domain, A578S, a low-frequency (3/78), nonsynonymous, single-nucleotide polymorphism associated with prolonged parasite clearance. PMID:26079933

  10. Slow Clearance of Plasmodium falciparum in Severe Pediatric Malaria, Uganda, 2011–2013

    PubMed Central

    Hawkes, Michael; Conroy, Andrea L.; Opoka, Robert O.; Namasopo, Sophie; Zhong, Kathleen; Liles, W. Conrad; John, Chandy C.

    2015-01-01

    Plasmodium falciparum resistance to artemisinin derivatives is emerging in Asia. We examined molecular markers of resistance in 78 children in Uganda who had severe malaria and were treated with intravenous artesunate. We observed in the K13-propeller domain, A578S, a low-frequency (3/78), nonsynonymous, single-nucleotide polymorphism associated with prolonged parasite clearance. PMID:26079933

  11. A non-pharmaceutical form of Artemisia annua is not effective in preventing Plasmodium falciparum malaria.

    PubMed

    Lagarce, Laurence; Lerolle, Nicolas; Asfar, Pierre; Le Govic, Yohann; Lainé-Cessac, Pascale; de Gentile, Ludovic

    2016-05-01

    Non-pharmaceutical forms of Artemisia annua (a Chinese plant containing artemisinin) are used by some travellers who believe these products are safer than anti-malarial drugs. We report two cases of severe Plasmodium falciparum malaria requiring hospitalization in an Intensive Care Unit following prophylaxis with non-pharmaceutical A. annua in French travellers. PMID:27432906

  12. Chemotherapy for falciparum malaria: the armoury, the problems and the prospects.

    PubMed

    Winstanley, P A

    2000-04-01

    Peter Winstanley here describes the pharmacology and therapeutics of the main drugs used for falciparum malaria in the tropical setting, rather than in the developed world, as an overview for newcomers to the field. He then examines some of the current major problems and prospects for the future.

  13. Rapid reemergence of T cells into peripheral circulation following treatment of severe and uncomplicated Plasmodium falciparum malaria.

    PubMed Central

    Hviid, L; Kurtzhals, J A; Goka, B Q; Oliver-Commey, J O; Nkrumah, F K; Theander, T G

    1997-01-01

    Frequencies and absolute numbers of peripheral T-cell subsets were monitored closely following acute Plasmodium falciparum malaria in 22 Ghanaian children from an area of hyperendemicity for seasonal malaria transmission. The children presented with cerebral or uncomplicated malaria (CM or UM, respectively) or with severe malarial anemia. For all patients the frequencies and absolute numbers of peripheral T cells were lower than normal during the acute stage of disease. This lowering was most pronounced in the CM group and least pronounced in the UM group. Of particular interest, the CM patients showed markedly reduced frequencies of CD4+ cells, the number of which also normalized slower than in the other clinical groups. In all patients, the T-cell frequencies gradually approached normal values after the initiation of therapy, whereas the absolute numbers rapidly reverted from lower than normal to higher than normal before returning to steady-state levels. Furthermore, the initially reduced T-cell surface density of the T-cell receptor/CD3 complex, which rapidly normalized, was a general finding for all three clinical groups, suggesting a state of peripheral T-cell hyporesponsiveness during acute malaria. The data presented suggest a rapid therapy-induced reemergence of T cells that had been temporarily removed from the peripheral circulation as a consequence of the malaria attack and that the degree of the disease-induced T-cell reallocation correlates with disease severity. PMID:9317012

  14. Proteomic analysis of Plasmodium falciparum induced alterations in humans from different endemic regions of India to decipher malaria pathogenesis and identify surrogate markers of severity.

    PubMed

    Ray, Sandipan; Kumar, Vipin; Bhave, Amruta; Singh, Vaidhvi; Gogtay, Nithya J; Thatte, Urmila M; Talukdar, Arunansu; Kochar, Sanjay K; Patankar, Swati; Srivastava, Sanjeeva

    2015-09-01

    India significantly contributes to the global malaria burden and has the largest population in the world at risk of malaria. This study aims to analyze alterations in the human serum proteome as a consequence of non-severe and severe infections by the malaria parasite Plasmodium falciparum to identify markers related to disease severity and to obtain mechanistic insights about disease pathogenesis and host immune responses. In discovery phase of the study, a comprehensive quantitative proteomic analysis was performed using gel-based (2D-DIGE) and gel-free (iTRAQ) techniques on two independent mass spectrometry platforms (ESI-Q-TOF and Q-Exactive mass spectrometry), and selected targets were validated by ELISA. Proteins showing altered serum abundance in falciparum malaria patients revealed the modulation of different physiological pathways including chemokine and cytokine signaling, IL-12 signaling and production in macrophages, complement cascades, blood coagulation, and protein ubiquitination pathways. Some muscle related and cytoskeletal proteins such as titin and galectin-3-binding protein were found to be up-regulated in severe malaria patients. Hemoglobin levels and platelet counts were also found to be drastically lower in severe malaria patients. Identified proteins including serum amyloid A, C-reactive protein, apolipoprotein E and haptoglobin, which exhibited sequential alterations in their serum abundance in different severity levels of malaria, could serve as potential predictive markers for disease severity. To the best of our information, we report here the first comprehensive analysis describing the serum proteomic alterations observed in severe P. falciparum infected patients from different malaria endemic regions of India. This article is part of a Special Issue entitled: Proteomics in India.

  15. Assessment of the therapeutic efficacy of artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria in northern KwaZulu-Natal: an observational cohort study

    PubMed Central

    2012-01-01

    Background Recent malaria epidemics in KwaZulu-Natal indicate that effective anti-malarial therapy is essential for malaria control. Although artemether-lumefantrine has been used as first-line treatment for uncomplicated Plasmodium falciparum malaria in northern KwaZulu-Natal since 2001, its efficacy has not been assessed since 2002. The objectives of this study were to quantify the proportion of patients treated for uncomplicated P. falciparum malaria with artemether-lumefantrine who failed treatment after 28 days, and to determine the prevalence of molecular markers associated with artemether-lumefantrine and chloroquine resistance. Methods An observational cohort of 49 symptomatic patients, diagnosed with uncomplicated P. falciparum malaria by rapid diagnostic test, had blood taken for malaria blood films and P. falciparum DNA polymerase chain reaction (PCR). Following diagnosis, patients were treated with artemether-lumefantrine (Coartem®) and invited to return to the health facility after 28 days for repeat blood film and PCR. All PCR P. falciparum positive samples were analysed for molecular markers of lumefantrine and chloroquine resistance. Results Of 49 patients recruited on the basis of a positive rapid diagnostic test, only 16 were confirmed to have P. falciparum by PCR. At follow-up, 14 were PCR-negative for malaria, one was lost to follow-up and one blood specimen had insufficient blood for a PCR analysis. All 16 with PCR-confirmed malaria carried a single copy of the multi-drug resistant (mdr1) gene, and the wild type asparagine allele mdr1 codon 86 (mdr1 86N). Ten of the 16 samples carried the wild type haplotype (CVMNK) at codons 72-76 of the chloroquine resistance transporter gene (pfcrt); three samples carried the resistant CVIET allele; one carried both the resistant and wild type, and in two samples the allele could not be analysed. Conclusions The absence of mdr1 gene copy number variation detected in this study suggests lumefantrine

  16. Immune mimicry in malaria: Plasmodium falciparum secretes a functional histamine-releasing factor homolog in vitro and in vivo

    PubMed Central

    MacDonald, Susan M.; Bhisutthibhan, Jamaree; Shapiro, Theresa A.; Rogerson, Stephen J.; Taylor, Terrie E.; Tembo, Madalitso; Langdon, Jacqueline M.; Meshnick, Steven R.

    2001-01-01

    The Plasmodium falciparum translationally controlled tumor protein (TCTP) is a homolog of the mammalian histamine-releasing factor (HRF), which causes histamine release from human basophils and IL-8 secretion from eosinophils. Histamine, IL-8, and eosinophils have been reported to be elevated in patients with malaria. This study was undertaken to determine whether malarial TCTP is found in the plasma of malaria-infected patients and to determine whether it has HRF biologic activity. Malarial TCTP was found in lightly infected human volunteers and in heavily infected Malawian children, but not in uninfected patients. Recombinant malarial TCTP, like HRF, stimulated histamine release from basophils and IL-8 secretion from eosinophils in vitro. Whereas malarial TCTP was less active than HRF, the concentrations that were effective in vitro could be achievable in vivo. These data suggest that malarial TCTP, present in human plasma during a malarial illness, may affect host immune responses in vivo. PMID:11535839

  17. Hypothesis: Dynamics of Classical Malaria Epidemics Show Plasmodium falciparum's Survival Strategy

    PubMed Central

    Shanks, G. Dennis

    2015-01-01

    Areas of marginal transmission can generate enormous lethal falciparum malaria epidemics when factors favoring the parasite shift only slightly. Although usually described in terms of vectorial capacity, medical scientists working in India in the early 20th century came to the conclusion that “an epidemic of relapses” was the key triggering event of malaria epidemics. This explanation has been largely discarded, because the biology of Plasmodium falciparum recrudescence has since been differentiated from P. vivax relapse. Using data from the Punjab in 1908 and Ceylon in 1934–1935, the genesis of malaria epidemics has been re-examined to inform current control efforts. The epidemics were focused geographically depending on recent rainfall or drought. Epidemics arose very suddenly and simultaneously in several places. Malaria spleen surveys indicated very little recent malaria transmission, and blood smears showed very few gametocytes just before the epidemic. Population stress as indicated by high grain prices because of a poor harvest caused by drought the previous year was a risk factor for malaria epidemics. Although increased female Anopheline survival because of increased humidity played an important part in the magnification of the epidemic, it does not explain its genesis. Human population stress triggering a shift toward gametocytogenesis is hypothesized as the key initiation factor for malaria epidemics. Its evolutionary significance may be that it allows the parasite to match the tropical agricultural cycle. PMID:25624407

  18. Transcriptomic evidence for modulation of host inflammatory responses during febrile Plasmodium falciparum malaria

    PubMed Central

    Tran, Tuan M.; Jones, Marcus B.; Ongoiba, Aissata; Bijker, Else M.; Schats, Remko; Venepally, Pratap; Skinner, Jeff; Doumbo, Safiatou; Quinten, Edwin; Visser, Leo G.; Whalen, Elizabeth; Presnell, Scott; O’Connell, Elise M.; Kayentao, Kassoum; Doumbo, Ogobara K.; Chaussabel, Damien; Lorenzi, Hernan; Nutman, Thomas B.; Ottenhoff, Tom H. M.; Haks, Mariëlle C.; Traore, Boubacar; Kirkness, Ewen F.; Sauerwein, Robert W.; Crompton, Peter D.

    2016-01-01

    Identifying molecular predictors and mechanisms of malaria disease is important for understanding how Plasmodium falciparum malaria is controlled. Transcriptomic studies in humans have so far been limited to retrospective analysis of blood samples from clinical cases. In this prospective, proof-of-principle study, we compared whole-blood RNA-seq profiles at pre-and post-infection time points from Malian adults who were either asymptomatic (n = 5) or febrile (n = 3) during their first seasonal PCR-positive P. falciparum infection with those from malaria-naïve Dutch adults after a single controlled human malaria infection (n = 5). Our data show a graded activation of pathways downstream of pro-inflammatory cytokines, with the highest activation in malaria-naïve Dutch individuals and significantly reduced activation in malaria-experienced Malians. Newly febrile and asymptomatic infections in Malians were statistically indistinguishable except for genes activated by pro-inflammatory cytokines. The combined data provide a molecular basis for the development of a pyrogenic threshold as individuals acquire immunity to clinical malaria. PMID:27506615

  19. Transcriptomic evidence for modulation of host inflammatory responses during febrile Plasmodium falciparum malaria.

    PubMed

    Tran, Tuan M; Jones, Marcus B; Ongoiba, Aissata; Bijker, Else M; Schats, Remko; Venepally, Pratap; Skinner, Jeff; Doumbo, Safiatou; Quinten, Edwin; Visser, Leo G; Whalen, Elizabeth; Presnell, Scott; O'Connell, Elise M; Kayentao, Kassoum; Doumbo, Ogobara K; Chaussabel, Damien; Lorenzi, Hernan; Nutman, Thomas B; Ottenhoff, Tom H M; Haks, Mariëlle C; Traore, Boubacar; Kirkness, Ewen F; Sauerwein, Robert W; Crompton, Peter D

    2016-01-01

    Identifying molecular predictors and mechanisms of malaria disease is important for understanding how Plasmodium falciparum malaria is controlled. Transcriptomic studies in humans have so far been limited to retrospective analysis of blood samples from clinical cases. In this prospective, proof-of-principle study, we compared whole-blood RNA-seq profiles at pre-and post-infection time points from Malian adults who were either asymptomatic (n = 5) or febrile (n = 3) during their first seasonal PCR-positive P. falciparum infection with those from malaria-naïve Dutch adults after a single controlled human malaria infection (n = 5). Our data show a graded activation of pathways downstream of pro-inflammatory cytokines, with the highest activation in malaria-naïve Dutch individuals and significantly reduced activation in malaria-experienced Malians. Newly febrile and asymptomatic infections in Malians were statistically indistinguishable except for genes activated by pro-inflammatory cytokines. The combined data provide a molecular basis for the development of a pyrogenic threshold as individuals acquire immunity to clinical malaria. PMID:27506615

  20. Vaccination with SPf66, a chemically synthesised vaccine, against Plasmodium falciparum malaria in Colombia.

    PubMed

    Valero, M V; Amador, L R; Galindo, C; Figueroa, J; Bello, M S; Murillo, L A; Mora, A L; Patarroyo, G; Rocha, C L; Rojas, M

    1993-03-20

    Preclinical and clinical studies have established the safety and immunogenicity of the chemically synthesised SPf66 malaria vaccine. The present study is a phase III randomised, double-blind, placebo-controlled, efficacy trial completed in La Tola, Colombia. 1548 volunteers over one year of age received three doses of either the vaccine (n = 738) or placebo (n = 810). Active and passive case detection methods were used to document clinical episodes of malaria among the study population. The follow-up period began one month after the third dose and lasted for one year. 168 and 297 episodes of Plasmodium falciparum malaria were documented in the SPf66 group and the placebo group, respectively; this corresponds to a crude protective efficacy of 38.8%. Incidence rates for first or only P falciparum malarial episodes were 22.3% per annum among the vaccinee group and 33.5% among the placebo group (RR = 1.5; 95% Cl 1.23, 1.84). Therefore, the protective efficacy of SPf66 against first or only episodes was 33.6% (95% Cl 18.8, 45.7), being highest in children aged 1-4 years (77%) and adults older than 45 years (67%). The estimated protective efficacy against second episodes was 50.5% (95% Cl 12.9-71.9). Our study shows that the chemically synthesised SPf66 malaria vaccine is safe, immunogenic, and protective against P falciparum malaria in semi-immune populations subject to natural challenge.

  1. Decreased Endothelial Nitric Oxide Bioavailability, Impaired Microvascular Function, and Increased Tissue Oxygen Consumption in Children with Falciparum Malaria

    PubMed Central

    Yeo, Tsin W.; Lampah, Daniel A.; Kenangalem, Enny; Tjitra, Emiliana; Weinberg, J. Brice; Granger, Donald L.; Price, Ric N.; Anstey, Nicholas M.

    2014-01-01

    Endothelial nitric oxide (NO) bioavailability, microvascular function, and host oxygen consumption have not been assessed in pediatric malaria. We measured NO-dependent endothelial function by using peripheral artery tonometry to determine the reactive hyperemia index (RHI), and microvascular function and oxygen consumption (VO2) using near infrared resonance spectroscopy in 13 Indonesian children with severe falciparum malaria and 15 with moderately severe falciparum malaria. Compared with 19 controls, children with severe malaria and those with moderately severe malaria had lower RHIs (P = .03); 12% and 8% lower microvascular function, respectively (P = .03); and 29% and 25% higher VO2, respectively. RHIs correlated with microvascular function in all children with malaria (P < .001) and all with severe malaria (P < .001). Children with malaria have decreased endothelial and microvascular function and increased oxygen consumption, likely contributing to the pathogenesis of the disease. PMID:24879801

  2. Decreased endothelial nitric oxide bioavailability, impaired microvascular function, and increased tissue oxygen consumption in children with falciparum malaria.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Kenangalem, Enny; Tjitra, Emiliana; Weinberg, J Brice; Granger, Donald L; Price, Ric N; Anstey, Nicholas M

    2014-11-15

    Endothelial nitric oxide (NO) bioavailability, microvascular function, and host oxygen consumption have not been assessed in pediatric malaria. We measured NO-dependent endothelial function by using peripheral artery tonometry to determine the reactive hyperemia index (RHI), and microvascular function and oxygen consumption (VO2) using near infrared resonance spectroscopy in 13 Indonesian children with severe falciparum malaria and 15 with moderately severe falciparum malaria. Compared with 19 controls, children with severe malaria and those with moderately severe malaria had lower RHIs (P = .03); 12% and 8% lower microvascular function, respectively (P = .03); and 29% and 25% higher VO2, respectively. RHIs correlated with microvascular function in all children with malaria (P < .001) and all with severe malaria (P < .001). Children with malaria have decreased endothelial and microvascular function and increased oxygen consumption, likely contributing to the pathogenesis of the disease.

  3. Tailoring a Pediatric Formulation of Artemether-Lumefantrine for Treatment of Plasmodium falciparum Malaria

    PubMed Central

    Ogutu, Bernhards; Djimde, Abdoulaye; Stricker, Kirstin; Hamed, Kamal

    2015-01-01

    Specially created pediatric formulations have the potential to improve the acceptability, effectiveness, and accuracy of dosing of artemisinin-based combination therapy (ACT) in young children, a patient group that is inherently vulnerable to malaria. Artemether-lumefantrine (AL) Dispersible is a pediatric formulation of AL that is specifically tailored for the treatment of children with uncomplicated Plasmodium falciparum malaria, offering benefits relating to efficacy, convenience and acceptance, accuracy of dosing, safety, sterility, stability, and a pharmacokinetic profile and bioequivalence similar to those of crushed and intact AL tablets. However, despite being the first pediatric antimalarial to meet World Health Organization (WHO) specifications for use in infants and children who are ≥5 kg in body weight and its inclusion in WHO Guidelines, there are few publications that focus on AL Dispersible. Based on a systematic review of the recent literature, this paper provides a comprehensive overview of the clinical experience with AL Dispersible to date. A randomized, phase 3 study that compared the efficacy and safety of AL Dispersible to those of crushed AL tablets in 899 African children reported high PCR-corrected cure rates at day 28 (97.8% and 98.5% for AL Dispersible and crushed tablets, respectively), and the results of several subanalyses of these data indicate that this activity is observed regardless of patient weight, food intake, and maximum plasma concentrations of artemether or its active metabolite, dihydroartemisinin. These and other clinical data support the continued use of pediatric antimalarial formulations in all children <5 years of age with uncomplicated malaria when accompanied by continued monitoring for the emergence of resistance. PMID:26014953

  4. Tailoring a Pediatric Formulation of Artemether-Lumefantrine for Treatment of Plasmodium falciparum Malaria.

    PubMed

    Bassat, Quique; Ogutu, Bernhards; Djimde, Abdoulaye; Stricker, Kirstin; Hamed, Kamal

    2015-08-01

    Specially created pediatric formulations have the potential to improve the acceptability, effectiveness, and accuracy of dosing of artemisinin-based combination therapy (ACT) in young children, a patient group that is inherently vulnerable to malaria. Artemether-lumefantrine (AL) Dispersible is a pediatric formulation of AL that is specifically tailored for the treatment of children with uncomplicated Plasmodium falciparum malaria, offering benefits relating to efficacy, convenience and acceptance, accuracy of dosing, safety, sterility, stability, and a pharmacokinetic profile and bioequivalence similar to those of crushed and intact AL tablets. However, despite being the first pediatric antimalarial to meet World Health Organization (WHO) specifications for use in infants and children who are ≥5 kg in body weight and its inclusion in WHO Guidelines, there are few publications that focus on AL Dispersible. Based on a systematic review of the recent literature, this paper provides a comprehensive overview of the clinical experience with AL Dispersible to date. A randomized, phase 3 study that compared the efficacy and safety of AL Dispersible to those of crushed AL tablets in 899 African children reported high PCR-corrected cure rates at day 28 (97.8% and 98.5% for AL Dispersible and crushed tablets, respectively), and the results of several subanalyses of these data indicate that this activity is observed regardless of patient weight, food intake, and maximum plasma concentrations of artemether or its active metabolite, dihydroartemisinin. These and other clinical data support the continued use of pediatric antimalarial formulations in all children <5 years of age with uncomplicated malaria when accompanied by continued monitoring for the emergence of resistance.

  5. Efficacy of Pyrimethamine/Sulfadoxine versus Chloroquine for the Treatment of Uncomplicated Falciparum Malaria in Children Aged Under 5 Years

    PubMed Central

    Zheng, W; Jiang, H; Xiong, Z; Jiang, Z; Chen, H

    2013-01-01

    The children aged under 5 years from vast African areas badly suffer from falciparum malaria and many of them die of this disease. Therapeutic efficacy of anti-malaria drugs, especially pyrimethamine-sulfadoxine (PS) and chloroquine (CQ) to falciparum malaria is frequently evaluated and reported in recent 10 years. Unfortunately, to date, these widespread materials and researches have not been systematically collected and analyzed. In our study, two investigators were employed to widely and independently gather researches on efficacy of PS vs. CQ mono-therapy of falciparum malaria in children aged below 5 years in unpublished and published databases. Meta-analyses were conducted in categories of PS group and CQ group respectively. Pooled OR of PS vs. CQ was 0.11 (95%CI, 0.05-0.24). PS showed higher therapeutic efficacy to falciparum malaria in less-than-5-year children than CQ. Random model was chosen to analyze for the heterogeneity existence between different studies. Subgroup analyses were performed, but heterogeneity was still presented. Heterogeneity might be caused by different resistance of falciparum malaria to PS and CQ in different settings. Malaria type associated with parasite species, basic information of PS and CQ, and PS & CQ resistant malaria control measures were demonstrated and discussed respectively in detail in this article. PMID:23682255

  6. Early treatment failure during treatment of Plasmodium falciparum malaria with atovaquone-proguanil in the Republic of Ivory Coast.

    PubMed

    Wurtz, Nathalie; Pascual, Aurélie; Marin-Jauffre, Adeline; Bouchiba, Housem; Benoit, Nicolas; Desbordes, Marc; Martelloni, Maryse; Pommier de Santi, Vincent; Richa, Georges; Taudon, Nicolas; Pradines, Bruno; Briolant, Sébastien

    2012-05-02

    The increased spread of drug-resistant malaria highlights the need for alternative drugs for treatment and chemoprophylaxis. The combination of atovaquone-proguanil (Malarone®) has shown high efficacy against Plasmodium falciparum with only mild side-effects. Treatment failures have been attributed to suboptimal dosages or to parasite resistance resulting from a point mutation in the cytochrome b gene. In this paper, a case of early treatment failure was reported in a patient treated with atovaquone-proguanil; this failure was not associated with a mutation in the parasite cytochrome b gene, with impaired drug bioavailability, or with re-infection.

  7. High levels of Plasmodium falciparum rosetting in all clinical forms of severe malaria in African children.

    PubMed

    Doumbo, Ogobara K; Thera, Mahamadou A; Koné, Abdoulaye K; Raza, Ahmed; Tempest, Louisa J; Lyke, Kirsten E; Plowe, Christopher V; Rowe, J Alexandra

    2009-12-01

    Plasmodium falciparum rosetting (the spontaneous binding of infected erythrocytes to uninfected erythrocytes) is a well-recognized parasite virulence factor. However, it is currently unclear whether rosetting is associated with all clinical forms of severe malaria, or only with specific syndromes such as cerebral malaria. We investigated the relationship between rosetting and clinical malaria in 209 Malian children enrolled in a case-control study of severe malaria. Rosetting was significantly higher in parasite isolates from severe malaria cases compared with non-severe hyperparasitemia and uncomplicated malaria controls (F(2,117) = 8.15, P < 0.001). Analysis of sub-categories of severe malaria (unrousable coma, severe anemia, non-comatose neurological impairment, repeated seizures or a small heterogeneous group with signs of renal failure or jaundice) showed high levels of rosetting in all sub-categories, and no statistically significant differences in rosetting between sub-categories (F(4,67) = 1.28, P = 0.28). Thus rosetting may contribute to the pathogenesis of all severe malaria syndromes in African children, and interventions to disrupt rosetting could be potential adjunctive therapies for all forms of severe malaria in Africa. PMID:19996426

  8. Prolonged neutrophil dysfunction after Plasmodium falciparum malaria is related to hemolysis and heme oxygenase-1 induction.

    PubMed

    Cunnington, Aubrey J; Njie, Madi; Correa, Simon; Takem, Ebako N; Riley, Eleanor M; Walther, Michael

    2012-12-01

    It is not known why people are more susceptible to bacterial infections such as nontyphoid Salmonella during and after a malaria infection, but in mice, malarial hemolysis impairs resistance to nontyphoid Salmonella by impairing the neutrophil oxidative burst. This acquired neutrophil dysfunction is a consequence of induction of the cytoprotective, heme-degrading enzyme heme oxygenase-1 (HO-1) in neutrophil progenitors in bone marrow. In this study, we assessed whether neutrophil dysfunction occurs in humans with malaria and how this relates to hemolysis. We evaluated neutrophil function in 58 Gambian children with Plasmodium falciparum malaria [55 (95%) with uncomplicated disease] and examined associations with erythrocyte count, haptoglobin, hemopexin, plasma heme, expression of receptors for heme uptake, and HO-1 induction. Malaria caused the appearance of a dominant population of neutrophils with reduced oxidative burst activity, which gradually normalized over 8 wk of follow-up. The degree of neutrophil impairment correlated significantly with markers of hemolysis and HO-1 induction. HO-1 expression was increased in blood during acute malaria, but at a cellular level HO-1 expression was modulated by changes in surface expression of the haptoglobin receptor (CD163). These findings demonstrate that neutrophil dysfunction occurs in P. falciparum malaria and support the relevance of the mechanistic studies in mice. Furthermore, they suggest the presence of a regulatory pathway to limit HO-1 induction by hemolysis in the context of infection and indicate new targets for therapeutic intervention to abrogate the susceptibility to bacterial infection in the context of hemolysis in humans.

  9. Parasitaemia and Its Relation to Hematological Parameters and Liver Function among Patients Malaria in Abs, Hajjah, Northwest Yemen.

    PubMed

    Al-Salahy, Mohamed; Shnawa, Bushra; Abed, Gamal; Mandour, Ahmed; Al-Ezzi, Ali

    2016-01-01

    Plasmodium falciparum malaria is the most common infection in Yemen. The present study aims to investigate changes in hematological and hepatic function indices of P. falciparum infected individuals. This study included 67 suspected falciparum malarial patients attended in clinics and rural Abs Hospital (Tehama, Hajjah), Yemen, from October 2013 to April 2014. The diagnosis of malaria was confirmed by thick and thin film with Giemsa staining of malaria parasite. Hematological parameters and serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and bilirubin (total and direct) as test indicators of liver function were studied. Patients with parasitaemia tended to have significantly lower hemoglobin, hematocrit, white blood cell count, lymphocytes, and platelets, compared with healthy normal subjects. Neutrophils levels were significantly higher in cases of falciparum malaria in comparison to healthy normal subjects. Serums AST, ALT, ALP, and bilirubin (total and direct) in falciparum malaria patients were significantly higher (p < 0.0001) than those of falciparum malaria of free individuals. Hematological and liver dysfunctions measured parameters were seen associated with moderate and severe parasitaemia infection. This study concludes that hematological and hepatic dysfunction parameters could be indicator of malaria in endemic regions. PMID:27051422

  10. Parasitaemia and Its Relation to Hematological Parameters and Liver Function among Patients Malaria in Abs, Hajjah, Northwest Yemen

    PubMed Central

    Al-Salahy, Mohamed; Shnawa, Bushra; Abed, Gamal; Mandour, Ahmed

    2016-01-01

    Plasmodium falciparum malaria is the most common infection in Yemen. The present study aims to investigate changes in hematological and hepatic function indices of P. falciparum infected individuals. This study included 67 suspected falciparum malarial patients attended in clinics and rural Abs Hospital (Tehama, Hajjah), Yemen, from October 2013 to April 2014. The diagnosis of malaria was confirmed by thick and thin film with Giemsa staining of malaria parasite. Hematological parameters and serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and bilirubin (total and direct) as test indicators of liver function were studied. Patients with parasitaemia tended to have significantly lower hemoglobin, hematocrit, white blood cell count, lymphocytes, and platelets, compared with healthy normal subjects. Neutrophils levels were significantly higher in cases of falciparum malaria in comparison to healthy normal subjects. Serums AST, ALT, ALP, and bilirubin (total and direct) in falciparum malaria patients were significantly higher (p < 0.0001) than those of falciparum malaria of free individuals. Hematological and liver dysfunctions measured parameters were seen associated with moderate and severe parasitaemia infection. This study concludes that hematological and hepatic dysfunction parameters could be indicator of malaria in endemic regions. PMID:27051422

  11. Earth Observation, Geographic Information Systems and Plasmodium falciparum Malaria in Sub-Saharan Africa

    PubMed Central

    Hay, S.I.; Omumbo, J.A.; Craig, M.H.; Snow, R. W.

    2011-01-01

    This review highlights the progress and current status of remote sensing (RS) and geographical information systems (GIS) as currently applied to the problem of Plasmodium falciparum malaria in sub-Saharan Africa (SSA). The burden of P. falciparum malaria in SSA is first summarized and then contrasted with the paucity of accurate and recent information on the nature and extent of the disease. This provides perspective on both the global importance of the pathogen and the potential for contribution of RS and GIS techniques. The ecology of P. falciparum malaria and its major anopheline vectors in SSA is then outlined, to provide the epidemiological background for considering disease transmission processes and their environmental correlates. Because RS and GIS are recent techniques in epidemiology, all mosquito-borne diseases are considered in this review in order to convey the range of ideas, insights and innovation provided. To conclude, the impact of these initial studies is assessed and suggestions provided on how these advances could be best used for malaria control in an appropriate and sustainable manner, with key areas for future research highlighted. PMID:10997207

  12. Sterile Protective Immunity to Malaria is Associated with a Panel of Novel P. falciparum Antigens*

    PubMed Central

    Trieu, Angela; Kayala, Matthew A.; Burk, Chad; Molina, Douglas M.; Freilich, Daniel A.; Richie, Thomas L.; Baldi, Pierre; Felgner, Philip L.; Doolan, Denise L.

    2011-01-01

    The development of an effective malaria vaccine remains a global public health priority. Less than 0.5% of the Plasmodium falciparum genome has been assessed as potential vaccine targets and candidate vaccines have been based almost exclusively on single antigens. It is possible that the failure to develop a malaria vaccine despite decades of effort might be attributed to this historic focus. To advance malaria vaccine development, we have fabricated protein microarrays representing 23% of the entire P. falciparum proteome and have probed these arrays with plasma from subjects with sterile protection or no protection after experimental immunization with radiation attenuated P. falciparum sporozoites. A panel of 19 pre-erythrocytic stage antigens was identified as strongly associated with sporozoite-induced protective immunity; 16 of these antigens were novel and 85% have been independently identified in sporozoite and/or liver stage proteomic or transcriptomic data sets. Reactivity to any individual antigen did not correlate with protection but there was a highly significant difference in the cumulative signal intensity between protected and not protected individuals. Functional annotation indicates that most of these signature proteins are involved in cell cycle/DNA processing and protein synthesis. In addition, 21 novel blood-stage specific antigens were identified. Our data provide the first evidence that sterile protective immunity against malaria is directed against a panel of novel P. falciparum antigens rather than one antigen in isolation. These results have important implications for vaccine development, suggesting that an efficacious malaria vaccine should be multivalent and targeted at a select panel of key antigens, many of which have not been previously characterized. PMID:21628511

  13. 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

  14. Identification of a Platelet Membrane Glycoprotein as a Falciparum Malaria Sequestration Receptor

    NASA Astrophysics Data System (ADS)

    Ockenhouse, Christian F.; Tandon, Narendra N.; Magowan, Cathleen; Jamieson, G. A.; Chulay, Jeffrey D.

    1989-03-01

    Infections with the human malaria parasite Plasmodium falciparum are characterized by sequestration of erythrocytes infected with mature forms of the parasite. Sequestration of infected erythrocytes appears to be critical for survival of the parasite and to mediate immunopathological abnormalities in severe malaria. A leukocyte differentiation antigen (CD36) was previously suggested to have a role in sequestration of malaria-infected erythrocytes. CD36 was purified from platelets, where it is known as GPIV, and was shown to be a receptor for binding of infected erythrocytes. Infected erythrocytes adhered to CD36 immobilized on plastic; purified CD36 exhibited saturable, specific binding to infected erythrocytes; and purified CD36 or antibodies to CD36 inhibited and reversed binding of infected erythrocytes to cultured endothelial cells and melanoma cells in vitro. The portion of the CD36 molecule that reverses cytoadherence may be useful therapeutically for rapid reversal of sequestration in cerebral malaria.

  15. A Malaria Diagnostic Tool Based on Computer Vision Screening and Visualization of Plasmodium falciparum Candidate Areas in Digitized Blood Smears

    PubMed Central

    Walliander, Margarita; Mårtensson, Andreas; Diwan, Vinod; Rahtu, Esa; Pietikäinen, Matti; Lundin, Mikael; Lundin, Johan

    2014-01-01

    Introduction Microscopy is the gold standard for diagnosis of malaria, however, manual evaluation of blood films is highly dependent on skilled personnel in a time-consuming, error-prone and repetitive process. In this study we propose a method using computer vision detection and visualization of only the diagnostically most relevant sample regions in digitized blood smears. Methods Giemsa-stained thin blood films with P. falciparum ring-stage trophozoites (n = 27) and uninfected controls (n = 20) were digitally scanned with an oil immersion objective (0.1 µm/pixel) to capture approximately 50,000 erythrocytes per sample. Parasite candidate regions were identified based on color and object size, followed by extraction of image features (local binary patterns, local contrast and Scale-invariant feature transform descriptors) used as input to a support vector machine classifier. The classifier was trained on digital slides from ten patients and validated on six samples. Results The diagnostic accuracy was tested on 31 samples (19 infected and 12 controls). From each digitized area of a blood smear, a panel with the 128 most probable parasite candidate regions was generated. Two expert microscopists were asked to visually inspect the panel on a tablet computer and to judge whether the patient was infected with P. falciparum. The method achieved a diagnostic sensitivity and specificity of 95% and 100% as well as 90% and 100% for the two readers respectively using the diagnostic tool. Parasitemia was separately calculated by the automated system and the correlation coefficient between manual and automated parasitemia counts was 0.97. Conclusion We developed a decision support system for detecting malaria parasites using a computer vision algorithm combined with visualization of sample areas with the highest probability of malaria infection. The system provides a novel method for blood smear screening with a significantly reduced need for visual examination and

  16. Plasmodium falciparum complicated malaria: Modulation and connectivity between exportome and variant surface antigen gene families.

    PubMed

    Subudhi, Amit Kumar; Boopathi, P A; Pandey, Isha; Kohli, Ramandeep; Karwa, Rohan; Middha, Sheetal; Acharya, Jyoti; Kochar, Sanjay K; Kochar, Dhanpat K; Das, Ashis

    2015-05-01

    In temperate and sub-tropical regions of Asia and Latin America, complicated malaria manifested as hepatic dysfunction or renal dysfunction is seen in all age groups. There has been a concerted focus on understanding the patho-physiological and molecular basis of complicated malaria in children, much less is known about it in adults. We report here, the analysis of data from a custom, cross strain microarray (Agilent Platform) using material from adult patient samples, showing hepatic dysfunction or renal failure. These are the most common manifestations seen in adults along with cerebral malaria. The data has been analyzed with reference to variant surface antigens, encoded by the var, rifin and stevor gene families. The differential regulation profiles of key genes (comparison between Plasmodium falciparum complicated and uncomplicated isolates) have been observed. The exportome has been analyzed using similar parameters. Gene ontology term based functional enrichment of differentially regulated genes identified, up-regulated genes statistically enriched (P<0.05) to critical biological processes like generation of precursor metabolite and energy, chromosome organization and electron transport chain. Systems network based functional enrichment of overall differentially regulated genes yielded a similar result. We are reporting here, up-regulation of var group B and C genes whose proteins are predicted to interact with CD36 receptor in the host, the up-regulation of domain cassette 13 (DC13) containing var group A, as also the up-regulation of group A rifins and many of the stevors. This is contrary to most other reports from pediatric patients, with cerebral malaria where the up-regulation of mostly var A group genes have been seen. A protein-protein interaction based network has been created and analysis performed. This co-expression and text mining based network has shown overall connectivity between the variant surface antigens (VSA) and the exportome. The up

  17. Plasmodium falciparum var genes expressed in children with severe malaria encode CIDRα1 domains.

    PubMed

    Jespersen, Jakob S; Wang, Christian W; Mkumbaye, Sixbert I; Minja, Daniel Tr; Petersen, Bent; Turner, Louise; Petersen, Jens Ev; Lusingu, John Pa; Theander, Thor G; Lavstsen, Thomas

    2016-01-01

    Most severe Plasmodium falciparum infections are experienced by young children. Severe symptoms are precipitated by vascular sequestration of parasites expressing a particular subset of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion molecules. Parasites binding human endothelial protein C receptor (EPCR) through the CIDRα1 domain of certain PfEMP1 were recently associated with severe malaria in children. However, it has remained unclear to which extend the EPCR-binding CIDRα1 domains epitomize PfEMP1 expressed in severe malaria. Here, we characterized the near full-length transcripts dominating the var transcriptome in children with severe malaria and found that the only common feature of the encoded PfEMP1 was CIDRα1 domains. Such genes were highly and dominantly expressed in both children with severe malarial anaemia and cerebral malaria. These observations support the hypothesis that the CIDRα1-EPCR interaction is key to the pathogenesis of severe malaria and strengthen the rationale for pursuing a vaccine or adjunctive treatment aiming at inhibiting or reducing the damaging effects of this interaction. PMID:27354391

  18. Plasmodium falciparum var genes expressed in children with severe malaria encode CIDRα1 domains.

    PubMed

    Jespersen, Jakob S; Wang, Christian W; Mkumbaye, Sixbert I; Minja, Daniel Tr; Petersen, Bent; Turner, Louise; Petersen, Jens Ev; Lusingu, John Pa; Theander, Thor G; Lavstsen, Thomas

    2016-01-01

    Most severe Plasmodium falciparum infections are experienced by young children. Severe symptoms are precipitated by vascular sequestration of parasites expressing a particular subset of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion molecules. Parasites binding human endothelial protein C receptor (EPCR) through the CIDRα1 domain of certain PfEMP1 were recently associated with severe malaria in children. However, it has remained unclear to which extend the EPCR-binding CIDRα1 domains epitomize PfEMP1 expressed in severe malaria. Here, we characterized the near full-length transcripts dominating the var transcriptome in children with severe malaria and found that the only common feature of the encoded PfEMP1 was CIDRα1 domains. Such genes were highly and dominantly expressed in both children with severe malarial anaemia and cerebral malaria. These observations support the hypothesis that the CIDRα1-EPCR interaction is key to the pathogenesis of severe malaria and strengthen the rationale for pursuing a vaccine or adjunctive treatment aiming at inhibiting or reducing the damaging effects of this interaction.

  19. Large-scale growth of the Plasmodium falciparum malaria parasite in a wave bioreactor.

    PubMed

    Dalton, John P; Demanga, Corine G; Reiling, Sarah J; Wunderlich, Juliane; Eng, Jenny W L; Rohrbach, Petra

    2012-01-01

    We describe methods for the large-scale in vitro culturing of synchronous and asynchronous blood-stage Plasmodium falciparum parasites in sterile disposable plastic bioreactors controlled by wave-induced motion (wave bioreactor). These cultures perform better than static flask cultures in terms of preserving parasite cell cycle synchronicity and reducing the number of multiple-infected erythrocytes. The straight-forward methods described here will facilitate the large scale production of malaria parasites for antigen and organelle isolation and characterisation, for the high throughput screening of compound libraries with whole cells or extracts, and the development of live- or whole-cell malaria vaccines under good manufacturing practice compliant standards.

  20. A fresh look at the origin of Plasmodium falciparum, the most malignant malaria agent.

    PubMed

    Prugnolle, Franck; Durand, Patrick; Ollomo, Benjamin; Duval, Linda; Ariey, Frédéric; Arnathau, Céline; Gonzalez, Jean-Paul; Leroy, Eric; Renaud, François

    2011-02-01

    From which host did the most malignant human malaria come: birds, primates, or rodents? When did the transfer occur? Over the last half century, these have been some of the questions up for debate about the origin of Plasmodium falciparum, the most common and deadliest human malaria parasite, which is responsible for at least one million deaths every year. Recent findings bring elements in favor of a transfer from great apes, but are these evidences really solid? What are the grey areas that remain to be clarified? Here, we examine in depth these new elements and discuss how they modify our perception of the origin and evolution of P. falciparum. We also discuss the perspectives these new discoveries open.

  1. Plasmodium falciparum kelch 13: a potential molecular marker for tackling artemisinin-resistant malaria parasites.

    PubMed

    Mita, Toshihiro; Tachibana, Shin-Ichiro; Hashimoto, Muneaki; Hirai, Makoto

    2016-01-01

    Although artemisinin combination therapies have been deployed as a first-line treatment for uncomplicated malaria in almost all endemic countries, artemisinin-resistant parasites have emerged and have gradually spread across the Greater Mekong subregions. There is growing concern that the resistant parasites may migrate to or emerge indigenously in sub-Saharan Africa, which might provoke a global increase in malaria-associated morbidity and mortality. Therefore, development of molecular markers that enable identification of artemisinin resistance with high sensitivity is urgently required to combat this issue. In 2014, a potential artemisinin-resistance responsible gene, Plasmodium falciparum kelch13, was discovered. Here, we review the genetic features of P. falciparum kelch13 and discuss its related resistant mechanisms and potential as a molecular marker.

  2. Serine Proteases of Malaria Parasite Plasmodium falciparum: Potential as Antimalarial Drug Targets

    PubMed Central

    2014-01-01

    Malaria is a major global parasitic disease and a cause of enormous mortality and morbidity. Widespread drug resistance against currently available antimalarials warrants the identification of novel drug targets and development of new drugs. Malarial proteases are a group of molecules that serve as potential drug targets because of their essentiality for parasite life cycle stages and feasibility of designing specific inhibitors against them. Proteases belonging to various mechanistic classes are found in P. falciparum, of which serine proteases are of particular interest due to their involvement in parasite-specific processes of egress and invasion. In P. falciparum, a number of serine proteases belonging to chymotrypsin, subtilisin, and rhomboid clans are found. This review focuses on the potential of P. falciparum serine proteases as antimalarial drug targets. PMID:24799897

  3. Plasmodium falciparum Histidine-Rich Protein II Compromises Brain Endothelial Barriers and May Promote Cerebral Malaria Pathogenesis

    PubMed Central

    Pal, Priya; Daniels, Brian P.; Oskman, Anna; Diamond, Michael S.; Klein, Robyn S.

    2016-01-01

    ABSTRACT Cerebral malaria (CM) is a disease of the vascular endothelium caused by Plasmodium falciparum. It is characterized by parasite sequestration, inflammatory cytokine production, and vascular leakage. A distinguishing feature of P. falciparum infection is parasite production and secretion of histidine-rich protein II (HRPII). Plasma HRPII is a diagnostic and prognostic marker for falciparum malaria. We demonstrate that disruption of a human cerebral microvascular endothelial barrier by P. falciparum-infected erythrocytes depends on expression of HRPII. Purified recombinant or native HRPII can recapitulate these effects. HRPII action occurs via activation of the inflammasome, resulting in decreased integrity of tight junctions and increased endothelial permeability. We propose that HRPII is a virulence factor that may contribute to cerebral malaria by compromising endothelial barrier integrity within the central nervous system. PMID:27273825

  4. Multiple dimensions of epigenetic gene regulation in the malaria parasite Plasmodium falciparum: gene regulation via histone modifications, nucleosome positioning and nuclear architecture in P. falciparum.

    PubMed

    Ay, Ferhat; Bunnik, Evelien M; Varoquaux, Nelle; Vert, Jean-Philippe; Noble, William Stafford; Le Roch, Karine G

    2015-02-01

    Plasmodium falciparum is the most deadly human malarial parasite, responsible for an estimated 207 million cases of disease and 627,000 deaths in 2012. Recent studies reveal that the parasite actively regulates a large fraction of its genes throughout its replicative cycle inside human red blood cells and that epigenetics plays an important role in this precise gene regulation. Here, we discuss recent advances in our understanding of three aspects of epigenetic regulation in P. falciparum: changes in histone modifications, nucleosome occupancy and the three-dimensional genome structure. We compare these three aspects of the P. falciparum epigenome to those of other eukaryotes, and show that large-scale compartmentalization is particularly important in determining histone decomposition and gene regulation in P. falciparum. We conclude by presenting a gene regulation model for P. falciparum that combines the described epigenetic factors, and by discussing the implications of this model for the future of malaria research.

  5. Genetic Diversity of Plasmodium falciparum Populations in Malaria Declining Areas of Sabah, East Malaysia

    PubMed Central

    Mohd Abd Razak, Mohd Ridzuan; Sastu, Umi Rubiah; Norahmad, Nor Azrina; Abdul-Karim, Abass; Muhammad, Amirrudin; Muniandy, Prem Kumar; Jelip, Jenarun; Rundi, Christina; Imwong, Mallika; Mudin, Rose Nani; Abdullah, Noor Rain

    2016-01-01

    Malaysia has a national goal to eliminate malaria by 2020. Understanding the genetic diversity of malaria parasites in residual transmission foci can provide invaluable information which may inform the intervention strategies used to reach elimination targets. This study was conducted to determine the genetic diversity level of P. falciparum isolates in malaria residual foci areas of Sabah. Malaria active case detection was conducted in Kalabakan and Kota Marudu. All individuals in the study sites were screened for malaria infection by rapid diagnostic test. Blood from P. falciparum-infected individuals were collected on filter paper prior to DNA extraction. Genotyping was performed using merozoite surface protein-1 (MSP-1), merozoite surface protein-2 (MSP-2), glutamate rich protein (GLURP) and 10 neutral microsatellite loci markers. The size of alleles, multiplicity of infection (MOI), mean number of alleles (Na), expected heterozygosity (He), linkage disequilibrium (LD) and genetic differentiation (FST) were determined. In Kalabakan, the MSP-1 and MSP-2 alleles were predominantly K1 and FC27 family types, respectively. The GLURP genotype VI (751–800 bp) was predominant. The MOI for MSP-1 and MSP-2 were 1.65 and 1.20, respectively. The Na per microsatellite locus was 1.70. The He values for MSP-1, MSP-2, GLURP and neutral microsatellites were 0.17, 0.37, 0.70 and 0.33, respectively. In Kota Marudu, the MSP-1 and MSP-2 alleles were predominantly MAD20 and 3D7 family types, respectively. The GLURP genotype IV (651–700 bp) was predominant. The MOI for both MSP-1 and MSP-2 was 1.05. The Na per microsatellite locus was 3.60. The He values for MSP-1, MSP-2, GLURP and neutral microsatellites were 0.24, 0.25, 0.69 and 0.30, respectively. A significant LD was observed in Kalabakan (0.495, p<0.01) and Kota Marudu P. falciparum populations (0.601, p<0.01). High genetic differentiation between Kalabakan and Kota Marudu P. falciparum populations was observed (FST = 0

  6. Genetic Diversity of Plasmodium falciparum Populations in Malaria Declining Areas of Sabah, East Malaysia.

    PubMed

    Mohd Abd Razak, Mohd Ridzuan; Sastu, Umi Rubiah; Norahmad, Nor Azrina; Abdul-Karim, Abass; Muhammad, Amirrudin; Muniandy, Prem Kumar; Jelip, Jenarun; Rundi, Christina; Imwong, Mallika; Mudin, Rose Nani; Abdullah, Noor Rain

    2016-01-01

    Malaysia has a national goal to eliminate malaria by 2020. Understanding the genetic diversity of malaria parasites in residual transmission foci can provide invaluable information which may inform the intervention strategies used to reach elimination targets. This study was conducted to determine the genetic diversity level of P. falciparum isolates in malaria residual foci areas of Sabah. Malaria active case detection was conducted in Kalabakan and Kota Marudu. All individuals in the study sites were screened for malaria infection by rapid diagnostic test. Blood from P. falciparum-infected individuals were collected on filter paper prior to DNA extraction. Genotyping was performed using merozoite surface protein-1 (MSP-1), merozoite surface protein-2 (MSP-2), glutamate rich protein (GLURP) and 10 neutral microsatellite loci markers. The size of alleles, multiplicity of infection (MOI), mean number of alleles (Na), expected heterozygosity (He), linkage disequilibrium (LD) and genetic differentiation (FST) were determined. In Kalabakan, the MSP-1 and MSP-2 alleles were predominantly K1 and FC27 family types, respectively. The GLURP genotype VI (751-800 bp) was predominant. The MOI for MSP-1 and MSP-2 were 1.65 and 1.20, respectively. The Na per microsatellite locus was 1.70. The He values for MSP-1, MSP-2, GLURP and neutral microsatellites were 0.17, 0.37, 0.70 and 0.33, respectively. In Kota Marudu, the MSP-1 and MSP-2 alleles were predominantly MAD20 and 3D7 family types, respectively. The GLURP genotype IV (651-700 bp) was predominant. The MOI for both MSP-1 and MSP-2 was 1.05. The Na per microsatellite locus was 3.60. The He values for MSP-1, MSP-2, GLURP and neutral microsatellites were 0.24, 0.25, 0.69 and 0.30, respectively. A significant LD was observed in Kalabakan (0.495, p<0.01) and Kota Marudu P. falciparum populations (0.601, p<0.01). High genetic differentiation between Kalabakan and Kota Marudu P. falciparum populations was observed (FST = 0

  7. Efficacy of artemether-lumefantrine, the nationally-recommended artemisinin combination for the treatment of uncomplicated falciparum malaria, in southern Laos

    PubMed Central

    2012-01-01

    Background The Lao Government changed the national policy for uncomplicated Plasmodium falciparum malaria from chloroquine to artemether-lumefantrine (AL) in 2005. Since then, no information on AL efficacy has been reported. With evidence of resistance to artemisinin derivatives in adjacent Cambodia, there has been a concern as to AL efficacy. Monitoring of AL efficacy would help the Lao Government to make decisions on appropriate malaria treatment. Methods The efficacy of a three-day, twice daily oral artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Xepon District, Savannakhet Province, southern Laos was studied over 42 days follow-up. This was part of a trial of thiamin supplementation in falciparum malaria. Results Of 630 patients with P. falciparum enrolled in the trial of thiamin treatment, 549 (87%, 357 children ≤15 years and 192 adults) were included in this study. The per protocol 42-day cure rates were 97% (524/541) [96% (337/352) for children and 99% (187/189) for adults, p = 0.042]. By conventional intention-to-treat analysis, the 42-day cure rates adjusted for re-infection, were 97% (532/549) [96% (342/357) in children and 99% (190/192) in adults, p = 0.042]. The proportion of patients who remained parasitaemic at day 1 after treatment was significantly higher in children [33% (116/356)] compared to adults [15% (28/192)] (p < 0.001) and only one adult patient had detectable parasitaemia on day 2. There were no serious adverse events. Potential side effects after treatment were reported more commonly in adults (32%) compared to children (15%) (p < 0.001). Patients with recrudescent infections were significantly younger, had longer mean time to fever clearance, and had longer median time to parasite clearance compared to those who were cured. Conclusions The current nationally-recommended anti-malarial treatment (artemether-lumefantrine) remains highly efficacious for the treatment of uncomplicated

  8. Parasite-induced permeation of nucleosides in Plasmodium falciparum malaria.

    PubMed

    Upston, J M; Gero, A M

    1995-06-14

    A mechanism which mediates the transport of the nonphysiological nucleoside, L-adenosine, was demonstrated in Plasmodium falciparum infected erythrocytes and naturally released merozoites. L-Adenosine was not a substrate for influx in freed intraerythrocytic parasites or in normal human erythrocytes nor was L-adenosine transported in a variety of cell types including other parasitic protozoa such as Crithidia luciliae, Trichomonas vaginalis, Giardia intestinalis, or the mammalian cells, Buffalo Green Monkey and HeLa cells. L-Adenosine transport in P. falciparum infected cells was nonsaturable, with a rate of 0.13 +/- 0.01 pmol/microliter cell water per s per microM L-adenosine, yet the transport was inhibited by furosemide, phloridzin and piperine with IC50 values between 1-13 microM, distinguishing the transport pathway from simple diffusion. The channel-like permeation was selective as disaccharides were not permeable to parasitised cells. In addition, an unusual metabolic property of parasitic adenosine deaminase was found in that L-adenosine was metabolised to L-inosine by both P. falciparum infected erythrocytes and merozoites, an activity which was inhibited by 50 nM deoxycoformycin. No other cell type examined displayed this enzymic activity. The results further substantiate that nucleoside transport in P. falciparum infected cells was significantly altered compared to uninfected erythrocytes and that L-adenosine transport and metabolism was a biochemical property of Plasmodium infected cells and merozoites and not found in normal erythrocytes nor any of the other cell types investigated.

  9. Standardization of the antibody-dependent respiratory burst assay with human neutrophils and Plasmodium falciparum malaria.

    PubMed

    Llewellyn, David; Miura, Kazutoyo; Fay, Michael P; Williams, Andrew R; Murungi, Linda M; Shi, Jianguo; Hodgson, Susanne H; Douglas, Alexander D; Osier, Faith H; Fairhurst, Rick M; Diakite, Mahamadou; Pleass, Richard J; Long, Carole A; Draper, Simon J

    2015-09-16

    The assessment of naturally-acquired and vaccine-induced immunity to blood-stage Plasmodium falciparum malaria is of long-standing interest. However, the field has suffered from a paucity of in vitro assays that reproducibly measure the anti-parasitic activity induced by antibodies in conjunction with immune cells. Here we optimize the antibody-dependent respiratory burst (ADRB) assay, which assesses the ability of antibodies to activate the release of reactive oxygen species from human neutrophils in response to P. falciparum blood-stage parasites. We focus particularly on assay parameters affecting serum preparation and concentration, and importantly assess reproducibility. Our standardized protocol involves testing each serum sample in singlicate with three independent neutrophil donors, and indexing responses against a standard positive control of pooled hyper-immune Kenyan sera. The protocol can be used to quickly screen large cohorts of samples from individuals enrolled in immuno-epidemiological studies or clinical vaccine trials, and requires only 6 μL of serum per sample. Using a cohort of 86 samples, we show that malaria-exposed individuals induce higher ADRB activity than malaria-naïve individuals. The development of the ADRB assay complements the use of cell-independent assays in blood-stage malaria, such as the assay of growth inhibitory activity, and provides an important standardized cell-based assay in the field.

  10. Schistosomiasis Coinfection in Children Influences Acquired Immune Response against Plasmodium falciparum Malaria Antigens

    PubMed Central

    Gaayeb, Lobna; Schacht, Anne-Marie; Charrier, Nicole; De Clerck, Dick; Dompnier, Jean-Pierre; Pillet, Sophie; Garraud, Olivier; N'Diaye, Abdoulaye A.; Riveau, Gilles

    2010-01-01

    Background Malaria and schistosomiasis coinfection frequently occurs in tropical countries. This study evaluates the influence of Schistosoma haematobium infection on specific antibody responses and cytokine production to recombinant merozoite surface protein-1-19 (MSP1-19) and schizont extract of Plasmodium falciparum in malaria-infected children. Methodology Specific IgG1 to MSP1-19, as well as IgG1 and IgG3 to schizont extract were significantly increased in coinfected children compared to P. falciparum mono-infected children. Stimulation with MSP1-19 lead to a specific production of both interleukin-10 (IL-10) and interferon-γ (IFN-γ), whereas the stimulation with schizont extract produced an IL-10 response only in the coinfected group. Conclusions Our study suggests that schistosomiasis coinfection favours anti-malarial protective antibody responses, which could be associated with the regulation of IL-10 and IFN-γ production and seems to be antigen-dependent. This study demonstrates the importance of infectious status of the population in the evaluation of acquired immunity against malaria and highlights the consequences of a multiple infection environment during clinical trials of anti-malaria vaccine candidates. PMID:20856680

  11. Defining Falciparum-Malaria-Attributable Severe Febrile Illness in Moderate-to-High Transmission Settings on the Basis of Plasma PfHRP2 Concentration

    PubMed Central

    Hendriksen, Ilse C. E.; White, Lisa J.; Veenemans, Jacobien; Mtove, George; Woodrow, Charles; Amos, Ben; Saiwaew, Somporn; Gesase, Samwel; Nadjm, Behzad; Silamut, Kamolrat; Joseph, Sarah; Chotivanich, Kesinee; Day, Nicholas P. J.; von Seidlein, Lorenz; Verhoef, Hans; Reyburn, Hugh; White, Nicholas J.; Dondorp, Arjen M.

    2013-01-01

    Background. In malaria-endemic settings, asymptomatic parasitemia complicates the diagnosis of malaria. Histidine-rich protein 2 (HRP2) is produced by Plasmodium falciparum, and its plasma concentration reflects the total body parasite burden. We aimed to define the malaria-attributable fraction of severe febrile illness, using the distributions of plasma P. falciparum HRP2 (PfHRP2) concentrations from parasitemic children with different clinical presentations. Methods. Plasma samples were collected from and peripheral blood slides prepared for 1435 children aged 6−60 months in communities and a nearby hospital in northeastern Tanzania. The study population included children with severe or uncomplicated malaria, asymptomatic carriers, and healthy control subjects who had negative results of rapid diagnostic tests. The distributions of plasma PfHRP2 concentrations among the different groups were used to model severe malaria-attributable disease. Results. The plasma PfHRP2 concentration showed a close correlation with the severity of infection. PfHRP2 concentrations of >1000 ng/mL denoted a malaria-attributable fraction of severe disease of 99% (95% credible interval [CI], 96%–100%), with a sensitivity of 74% (95% CI, 72%–77%), whereas a concentration of <200 ng/mL denoted severe febrile illness of an alternative diagnosis in >10% (95% CI, 3%–27%) of patients. Bacteremia was more common among patients in the lowest and highest PfHRP2 concentration quintiles. Conclusions. The plasma PfHRP2 concentration defines malaria-attributable disease and distinguishes severe malaria from coincidental parasitemia in African children in a moderate-to-high transmission setting. PMID:23136222

  12. In vivo drug resistance of falciparum malaria in mining areas of Venezuela.

    PubMed

    Aché, A; Escorihuela, M; Vivas, E; Páez, E; Miranda, L; Matos, A; Pérez, W; Díaz, O; Izarra, E

    2002-09-01

    The Lot Quality Assurance Double-Sampling Plan (LQADSP) technique was used in three areas, Maripa, Kilómetro 88 and Ikabaru, to assess the efficacy of antimalarials used routinely by the Venezuelan Malaria Programme. The use of chloroquine (25 mg/kg), chloroquine (40 mg/kg) and the combination of sulfadoxine (500 mg) and pyrimethamine (25 mg) registered treatment failures above the threshold level of 25% in Maripa and Kilómertro 88. In Ikabaru the use of chloroquine (40 mg/kg) did not surpass that quality level and could possibly be less than 10%. Quinine (30 mg/kg) was totally effective in curing patients in all three areas. The use of this technique seems adequate for rapid field evaluations and in this case for providing appropriate information to assist this health programme. However, whilst being an ideal technique for surveying areas in which considerable variation may exist among lots and particularly for Plasmodium falciparum infections in these areas, repeated surveys should be carried out in the same areas over time to monitor changes in the susceptibility of this parasite to first-, second- and third-line drugs. In that way, national drug policies can be modified adequately. PMID:12225503

  13. The spatial and temporal patterns of falciparum and vivax malaria in Perú: 1994–2006

    PubMed Central

    Chowell, Gerardo; Munayco, Cesar V; Escalante, Ananias A; McKenzie, F Ellis

    2009-01-01

    Background Malaria is the direct cause of approximately one million deaths worldwide each year, though it is both preventable and curable. Increasing the understanding of the transmission dynamics of falciparum and vivax malaria and their relationship could suggest improvements for malaria control efforts. Here the weekly number of malaria cases due to Plasmodium falciparum (1994–2006) and Plasmodium vivax (1999–2006) in Perú at different spatial scales in conjunction with associated demographic, geographic and climatological data are analysed. Methods Malaria periodicity patterns were analysed through wavelet spectral analysis, studied patterns of persistence as a function of community size and assessed spatial heterogeneity via the Lorenz curve and the summary Gini index. Results Wavelet time series analyses identified annual cycles in the incidence of both malaria species as the dominant pattern. However, significant spatial heterogeneity was observed across jungle, mountain and coastal regions with slightly higher levels of spatial heterogeneity for P. vivax than P. falciparum. While the incidence of P. falciparum has been declining in recent years across geographic regions, P. vivax incidence has remained relatively steady in jungle and mountain regions with a slight decline in coastal regions. Factors that may be contributing to this decline are discussed. The time series of both malaria species were significantly synchronized in coastal (ρ = 0.9, P < 0.0001) and jungle regions (ρ = 0.76, P < 0.0001) but not in mountain regions. Community size was significantly associated with malaria persistence due to both species in jungle regions, but not in coastal and mountain regions. Conclusion Overall, findings highlight the importance of highly refined spatial and temporal data on malaria incidence together with demographic and geographic information in improving the understanding of malaria persistence patterns associated with multiple malaria species in

  14. Cortisol, prolactin, cytokines and the susceptibility of pregnant Sudanese women to Plasmodium falciparum malaria.

    PubMed

    Bayoumi, N K; Elhassan, E M; Elbashir, M I; Adam, I

    2009-03-01

    Understanding the hormonal and cytokine interactions that underlie susceptibility to the disease should be helpful in elucidating the pathogenesis of malaria during pregnancy. The current study was conducted in the Wad Medani hospital, in an area of central Sudan that is characterised by unstable malarial transmission. Its aims were to investigate the roles and interactions of cortisol, prolactin, interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and interleukin-10 (IL-10) in pregnant women with Plasmodium falciparum malaria. The 82 pregnant subjects who were enrolled either had uncomplicated, P. falciparum malaria (the 47 cases) or were apparently uninfected and healthy women (the 37 controls) who were similar to the cases in terms of their mean age, weight, gravidity, gestational age and haemoglobin concentration. Compared with the controls, the cases were found to have significantly higher serum concentrations of total cortisol and IL-10 and significantly lower levels of prolactin and IFN-gamma (but similar concentrations of IL-4). The hormone and cytokine concentrations measured in the infected primigravidae were similar to those recorded in the infected multigravidae. Among the cases, there was a significant positive correlation between serum cortisol and IL-10 (r=0.188; P=0.025) and significant negative correlations between prolactin and both IL-4 (r=-0.175; P=0.038) and IL-10 (r=-0.186; P=0.027) but no significant correlation between prolactin and cortisol. During pregnancy, immune responses appear to be influenced by P. falciparum infections, irrespective of parity. Cortisol, prolactin and some cytokines appear to be key mediators in the host response to P. ?falciparum infection, although further research on this subject is clearly needed.

  15. The effect of malaria control on Plasmodium falciparum in Africa between 2000 and 2015.

    PubMed

    Bhatt, S; Weiss, D J; Cameron, E; Bisanzio, D; Mappin, B; Dalrymple, U; Battle, K E; Moyes, C L; Henry, A; Eckhoff, P A; Wenger, E A; Briët, O; Penny, M A; Smith, T A; Bennett, A; Yukich, J; Eisele, T P; Griffin, J T; Fergus, C A; Lynch, M; Lindgren, F; Cohen, J M; Murray, C L J; Smith, D L; Hay, S I; Cibulskis, R E; Gething, P W

    2015-10-01

    Since the year 2000, a concerted campaign against malaria has led to unprecedented levels of intervention coverage across sub-Saharan Africa. Understanding the effect of this control effort is vital to inform future control planning. However, the effect of malaria interventions across the varied epidemiological settings of Africa remains poorly understood owing to the absence of reliable surveillance data and the simplistic approaches underlying current disease estimates. Here we link a large database of malaria field surveys with detailed reconstructions of changing intervention coverage to directly evaluate trends from 2000 to 2015, and quantify the attributable effect of malaria disease control efforts. We found that Plasmodium falciparum infection prevalence in endemic Africa halved and the incidence of clinical disease fell by 40% between 2000 and 2015. We estimate that interventions have averted 663 (542-753 credible interval) million clinical cases since 2000. Insecticide-treated nets, the most widespread intervention, were by far the largest contributor (68% of cases averted). Although still below target levels, current malaria interventions have substantially reduced malaria disease incidence across the continent. Increasing access to these interventions, and maintaining their effectiveness in the face of insecticide and drug resistance, should form a cornerstone of post-2015 control strategies.

  16. The effect of malaria control on Plasmodium falciparum in Africa between 2000 and 2015.

    PubMed

    Bhatt, S; Weiss, D J; Cameron, E; Bisanzio, D; Mappin, B; Dalrymple, U; Battle, K E; Moyes, C L; Henry, A; Eckhoff, P A; Wenger, E A; Briët, O; Penny, M A; Smith, T A; Bennett, A; Yukich, J; Eisele, T P; Griffin, J T; Fergus, C A; Lynch, M; Lindgren, F; Cohen, J M; Murray, C L J; Smith, D L; Hay, S I; Cibulskis, R E; Gething, P W

    2015-10-01

    Since the year 2000, a concerted campaign against malaria has led to unprecedented levels of intervention coverage across sub-Saharan Africa. Understanding the effect of this control effort is vital to inform future control planning. However, the effect of malaria interventions across the varied epidemiological settings of Africa remains poorly understood owing to the absence of reliable surveillance data and the simplistic approaches underlying current disease estimates. Here we link a large database of malaria field surveys with detailed reconstructions of changing intervention coverage to directly evaluate trends from 2000 to 2015, and quantify the attributable effect of malaria disease control efforts. We found that Plasmodium falciparum infection prevalence in endemic Africa halved and the incidence of clinical disease fell by 40% between 2000 and 2015. We estimate that interventions have averted 663 (542-753 credible interval) million clinical cases since 2000. Insecticide-treated nets, the most widespread intervention, were by far the largest contributor (68% of cases averted). Although still below target levels, current malaria interventions have substantially reduced malaria disease incidence across the continent. Increasing access to these interventions, and maintaining their effectiveness in the face of insecticide and drug resistance, should form a cornerstone of post-2015 control strategies. PMID:26375008

  17. Changes in cytokine production associated with acquired immunity to Plasmodium falciparum malaria

    PubMed Central

    Rhee, M S M; Akanmori, B D; Waterfall, M; Riley, E M

    2001-01-01

    Individuals living in malaria-endemic areas eventually develop clinical immunity to Plasmodium falciparum. That is, they are able to limit blood parasite densities to extremely low levels and fail to show symptoms of infection. As the clinical symptoms of malaria infection are mediated in part by pro-inflammatory cytokines it is not clear whether the acquisition of clinical immunity is due simply to the development of antiparasitic mechanisms or whether the ability to regulate inflammatory cytokine production is also involved. We hypothesize that there is a correlation between risk of developing clinical malaria and the tendency to produce high levels of proinflammatory cytokines in response to malaria infection. In order to test this hypothesis, we have compared the ability of peripheral blood mononuclear cells from malaria-naive and malaria-exposed adult donors to proliferate and to secrete IFN-γ in response to P. falciparum schizont extract (PfSE). In order to determine how PfSE-induced IFN-γ production is regulated, we have also measured production of IL-12p40 and IL-10 from PfSE-stimulated PBMC and investigated the role of neutralizing antibody to IL-12 in modulating IFN-γ production. We find that cells from naive donors produce moderate amounts of IFN-γ in response to PfSE and that IFN-γ production is strongly IL-12 dependent. Cells from malaria-exposed donors living in an area of low malaria endemicity produce much higher levels of IFN-γ and this response is also at least partially IL-12 dependent. In complete contrast, cells from donors living in an area of very high endemicity produce minimal amounts of IFN-γ. No significant differences were detected between the groups in IL-10 production, suggesting that this cytokine does not play a major role in regulating malaria-induced IFN-γ production. The data from this study thus strongly support the hypothesis that down-regulation of inflammatory cytokine production may be a component of acquired clinical

  18. Impaired systemic tetrahydrobiopterin bioavailability and increased oxidized biopterins in pediatric falciparum malaria: association with disease severity.

    PubMed

    Rubach, Matthew P; Mukemba, Jackson; Florence, Salvatore; Lopansri, Bert K; Hyland, Keith; Volkheimer, Alicia D; Yeo, Tsin W; Anstey, Nicholas M; Weinberg, J Brice; Mwaikambo, Esther D; Granger, Donald L

    2015-03-01

    Decreased bioavailability of nitric oxide (NO) is a major contributor to the pathophysiology of severe falciparum malaria. Tetrahydrobiopterin (BH4) is an enzyme cofactor required for NO synthesis from L-arginine. We hypothesized that systemic levels of BH₄ would be decreased in children with cerebral malaria, contributing to low NO bioavailability. In an observational study in Tanzania, we measured urine levels of biopterin in its various redox states (fully reduced [BH₄] and the oxidized metabolites, dihydrobiopterin [BH₂] and biopterin [B₀]) in children with uncomplicated malaria (UM, n = 55), cerebral malaria (CM, n = 45), non-malaria central nervous system conditions (NMC, n = 48), and in 111 healthy controls (HC). Median urine BH4 concentration in CM (1.10 [IQR:0.55-2.18] μmol/mmol creatinine) was significantly lower compared to each of the other three groups - UM (2.10 [IQR:1.32-3.14];p<0.001), NMC (1.52 [IQR:1.01-2.71];p = 0.002), and HC (1.60 [IQR:1.15-2.23];p = 0.005). Oxidized biopterins were increased, and the BH4:BH2 ratio markedly decreased in CM. In a multivariate logistic regression model, each Log10-unit decrease in urine BH4 was independently associated with a 3.85-fold (95% CI:1.89-7.61) increase in odds of CM (p<0.001). Low systemic BH4 levels and increased oxidized biopterins contribute to the low NO bioavailability observed in CM. Adjunctive therapy to regenerate BH4 may have a role in improving NO bioavailability and microvascular perfusion in severe falciparum malaria.

  19. A Randomised Controlled Trial to Assess the Efficacy of Dihydroartemisinin-Piperaquine for the Treatment of Uncomplicated Falciparum Malaria in Peru

    PubMed Central

    Grande, Tanilu; Bernasconi, Andrea; Erhart, Annette; Gamboa, Dioni; Casapia, Martin; Delgado, Christopher; Torres, Kathy; Fanello, Caterina; Llanos-Cuentas, Alejandro; D'Alessandro, Umberto

    2007-01-01

    Background Multi-drug resistant falciparum malaria is an important health problem in the Peruvian Amazon region. We carried out a randomised open label clinical trial comparing mefloquine-artesunate, the current first line treatment in this region, with dihydroartemisinin-piperaquine. Methods and Findings Between July 2003 and July 2005, 522 patients with P. falciparum uncomplicated malaria were recruited, randomized (260 with mefloquine-artesunate and 262 with dihydroartemisinin-piperaquine), treated and followed up for 63 days. PCR-adjusted adequate clinical and parasitological response, estimated by Kaplan Meier survival and Per Protocol analysis, was extremely high for both drugs (99.6% for mefloquine-artesunate and 98.4% and for dihydroartemisinin-piperaquine) (RR: 0.99, 95%CI [0.97−1.01], Fisher Exact p = 0.21). All recrudescences were late parasitological failures. Overall, gametocytes were cleared faster in the mefloquine-artesunate group (28 vs 35 days) and new gametocytes tended to appear more frequently in patients treated with dihydroartemisinin-piperaquine (day 7: 8 (3.6%) vs 2 (0.9%), RR: 3.84, 95%CI [0.82–17.87]). Adverse events such as anxiety and insomnia were significantly more frequent in the mefloquine-artesunate group, both in adults and children. Conclusion Dihydroartemisinin-piperaquine is as effective as mefloquine-artesunate in treating uncomplicated P. falciparum malaria but it is better tolerated and more affordable than mefloquine-artesunate (US$1.0 versus US$18.65 on the local market). Therefore, it should be considered as a potential candidate for the first line treatment of P.falciparum malaria in Peru. Trial Registration ClinicalTrials.gov NCT00373607 PMID:17971864

  20. High efficacy of short-term quinine-antibiotic combinations for treating adult malaria patients in an area in which malaria is hyperendemic.

    PubMed Central

    Metzger, W; Mordmüller, B; Graninger, W; Bienzle, U; Kremsner, P G

    1995-01-01

    In a randomized trial, a three-dose quinine monotherapy was compared with short-term combination regimens of quinine-clindamycin and quinine-doxycycline for treating adult Gabonese patients with Plasmodium falciparum malaria. In quinine-treated patients, only 38% were ultimately cured. In contrast, more than 90% of patients were cured after treatment with either combination regimen. PMID:7695315

  1. K13-Propeller Polymorphisms in Plasmodium falciparum Isolates from Patients in Mayotte in 2013 and 2014.

    PubMed

    Torrentino-Madamet, Marylin; Collet, Louis; Lepère, Jean François; Benoit, Nicolas; Amalvict, Rémy; Ménard, Didier; Pradines, Bruno

    2015-12-01

    Plasmodium falciparum isolates were collected from 29 malaria patients treated with artemether-lumefantrine in Mayotte in 2013 and 2014. Twenty-four cases (83%) consisted of imported malaria. Seventeen percent of the isolates presented mutations in one of the six K13-propeller blades (N490H, F495L, N554H/K, and E596G). A total of 23.8% of the isolates from the Union of Comoros showed K13-propeller polymorphisms. Three of the 18 isolates (16.7%) from Grande Comore showed polymorphisms (N490H, N554K, and E596G).

  2. K13-Propeller Polymorphisms in Plasmodium falciparum Isolates from Patients in Mayotte in 2013 and 2014.

    PubMed

    Torrentino-Madamet, Marylin; Collet, Louis; Lepère, Jean François; Benoit, Nicolas; Amalvict, Rémy; Ménard, Didier; Pradines, Bruno

    2015-12-01

    Plasmodium falciparum isolates were collected from 29 malaria patients treated with artemether-lumefantrine in Mayotte in 2013 and 2014. Twenty-four cases (83%) consisted of imported malaria. Seventeen percent of the isolates presented mutations in one of the six K13-propeller blades (N490H, F495L, N554H/K, and E596G). A total of 23.8% of the isolates from the Union of Comoros showed K13-propeller polymorphisms. Three of the 18 isolates (16.7%) from Grande Comore showed polymorphisms (N490H, N554K, and E596G). PMID:26416865

  3. Relationship between Antibody Levels, IgG Binding to Plasmodium falciparum-Infected Erythrocytes, and Disease Outcome in Hospitalized Urban Malaria Patients from Dakar, Sénégal

    PubMed Central

    Mbengue, Babacar; Fall, Mouhamadou Mansour; Sylla Niang, Maguette; Niang, Birahim; Varela, Marie Louise; Diatta, Antoine Marie; Mbow, Moustapha; Ndiaye, Kantome; Ndiaye Diallo, Rokhaya; Dieye, Alioune; Perraut, Ronald

    2016-01-01

    Background. Management of clinical malaria requires the development of reliable diagnostic methods and efficient biomarkers for follow-up of patients. Protection is partly based on IgG responses to parasite antigens exposed at the surface of infected erythrocytes (iRBCs). These IgG responses appeared low during clinical infection, particularly in severe disease. Methods. We analyzed the IgG binding capacity to the surface of live erythrocytes infected by knob positive FCR3 strain. Sera from 69 cerebral malaria (CM) and 72 mild malaria (MM) cases were analyzed by ELISA for IgG responses to five antigens from iRBC and by flow cytometry for IgG binding as expressed in labeling index ratio (LIR). The relationship between IgG levels, LIR, parasitemia, age, and the clinical outcomes was evaluated. Results. We found a significant decrease of LIR in adult CM fatal cases compared to surviving patients (p = 0.019). In MM, LIRs were correlated to IgG anti-iRBC and anti-PfEMP3/5 levels. In CM, no correlation was found between LIR, IgG levels, and parasitemia. Conclusion. The IgG binding assay was able to discriminate outcome of cerebral malaria cases and it deserves further development as a potential functional-associated assay for symptomatic malaria analysis. PMID:27563669

  4. Relationship between Antibody Levels, IgG Binding to Plasmodium falciparum-Infected Erythrocytes, and Disease Outcome in Hospitalized Urban Malaria Patients from Dakar, Sénégal.

    PubMed

    Mbengue, Babacar; Fall, Mouhamadou Mansour; Sylla Niang, Maguette; Niang, Birahim; Varela, Marie Louise; Diatta, Antoine Marie; Mbow, Moustapha; Ndiaye, Kantome; Ndiaye Diallo, Rokhaya; Dieye, Alioune; Perraut, Ronald

    2016-01-01

    Background. Management of clinical malaria requires the development of reliable diagnostic methods and efficient biomarkers for follow-up of patients. Protection is partly based on IgG responses to parasite antigens exposed at the surface of infected erythrocytes (iRBCs). These IgG responses appeared low during clinical infection, particularly in severe disease. Methods. We analyzed the IgG binding capacity to the surface of live erythrocytes infected by knob positive FCR3 strain. Sera from 69 cerebral malaria (CM) and 72 mild malaria (MM) cases were analyzed by ELISA for IgG responses to five antigens from iRBC and by flow cytometry for IgG binding as expressed in labeling index ratio (LIR). The relationship between IgG levels, LIR, parasitemia, age, and the clinical outcomes was evaluated. Results. We found a significant decrease of LIR in adult CM fatal cases compared to surviving patients (p = 0.019). In MM, LIRs were correlated to IgG anti-iRBC and anti-PfEMP3/5 levels. In CM, no correlation was found between LIR, IgG levels, and parasitemia. Conclusion. The IgG binding assay was able to discriminate outcome of cerebral malaria cases and it deserves further development as a potential functional-associated assay for symptomatic malaria analysis. PMID:27563669

  5. Molecular Investigation into a Malaria Outbreak in Cusco, Peru: Plasmodium falciparum BV1 Lineage is Linked to a Second Outbreak in Recent Times.

    PubMed

    Okoth, Sheila Akinyi; Chenet, Stella M; Arrospide, Nancy; Gutierrez, Sonia; Cabezas, Cesar; Matta, Jose Antonio; Udhayakumar, Venkatachalam

    2016-01-01

    In November 2013, a Plasmodium falciparum malaria outbreak of 11 cases occurred in Cusco, southern Peru, where falciparum malaria had not been reported since 1946. Although initial microscopic diagnosis reported only Plasmodium vivax infection in each of the specimens, subsequent examination by the national reference laboratory confirmed P. falciparum infection in all samples. Molecular typing of four available isolates revealed identity as the B-variant (BV1) strain that was responsible for a malaria outbreak in Tumbes, northern Peru, between 2010 and 2012. The P. falciparum BV1 strain is multidrug resistant, can escape detection by PfHRP2-based rapid diagnostic tests, and has contributed to two malaria outbreaks in Peru. This investigation highlights the importance of accurate species diagnosis given the potential for P. falciparum to be reintroduced to regions where it may have been absent. Similar molecular epidemiological investigations can track the probable source(s) of outbreak parasite strains for malaria surveillance and control purposes.

  6. Molecular Investigation into a Malaria Outbreak in Cusco, Peru: Plasmodium falciparum BV1 Lineage is Linked to a Second Outbreak in Recent Times.

    PubMed

    Okoth, Sheila Akinyi; Chenet, Stella M; Arrospide, Nancy; Gutierrez, Sonia; Cabezas, Cesar; Matta, Jose Antonio; Udhayakumar, Venkatachalam

    2016-01-01

    In November 2013, a Plasmodium falciparum malaria outbreak of 11 cases occurred in Cusco, southern Peru, where falciparum malaria had not been reported since 1946. Although initial microscopic diagnosis reported only Plasmodium vivax infection in each of the specimens, subsequent examination by the national reference laboratory confirmed P. falciparum infection in all samples. Molecular typing of four available isolates revealed identity as the B-variant (BV1) strain that was responsible for a malaria outbreak in Tumbes, northern Peru, between 2010 and 2012. The P. falciparum BV1 strain is multidrug resistant, can escape detection by PfHRP2-based rapid diagnostic tests, and has contributed to two malaria outbreaks in Peru. This investigation highlights the importance of accurate species diagnosis given the potential for P. falciparum to be reintroduced to regions where it may have been absent. Similar molecular epidemiological investigations can track the probable source(s) of outbreak parasite strains for malaria surveillance and control purposes. PMID:26483121

  7. Malaria.

    PubMed

    Garcia, Lynne S

    2010-03-01

    Malaria has had a greater impact on world history than any other infectious disease. More than 300 to 500 million individuals worldwide are infected with Plasmodium spp, and 1.5 to 2.7 million people a year, most of whom are children, die from the infection. Malaria is endemic in over 90 countries in which 2400 million people live; this represents 40% of the world's population. Approximately 90% of malaria deaths occur in Africa. Despite continuing efforts in vaccine development, malaria prevention is difficult, and no drug is universally effective. This article examines malaria caused by the 4 most common Plasmodium spp that infect humans, P vivax, P ovale, P malariae, and P falciparum, as well as mixed infections and the simian parasite P knowlesi. A comprehensive review of the microbiology, clinical presentation, pathogenesis, diagnosis, and treatment of these forms of malaria is given.

  8. A High Malaria Prevalence Identified by PCR among Patients with Acute Undifferentiated Fever in India

    PubMed Central

    Haanshuus, Christel Gill; Chandy, Sara; Manoharan, Anand; Vivek, Rosario; Mathai, Dilip; Xena, Deepika; Singh, Ashita; Langeland, Nina; Blomberg, Bjørn; Vasanthan, George; Sitaram, Usha; Appasamy, Jonathan; Nesaraj, Joel; Henry, Anil; Patil, Suvarna; Alvarez-Uria, Gerardo; Armstrong, Lois; Mørch, Kristine

    2016-01-01

    Background Approximately one million malaria cases were reported in India in 2015, based on microscopy. This study aims to assess the malaria prevalence among hospitalised fever patients in India identified by PCR, and to evaluate the performance of routine diagnostic methods. Methods During June 2011-December 2012, patients admitted with acute undifferentiated fever to seven secondary level community hospitals in Assam (Tezpur), Bihar (Raxaul), Chhattisgarh (Mungeli), Maharashtra (Ratnagiri), Andhra Pradesh (Anantapur) and Tamil Nadu (Oddanchatram and Ambur) were included. The malaria prevalence was assessed by polymerase chain reaction (PCR), routine microscopy, and a rapid diagnostic test (RDT) with PCR as a reference method. Results The malaria prevalence by PCR was 19% (268/1412) ranging from 6% (Oddanchatram, South India) to 35% (Ratnagiri, West India). Among malaria positive patients P. falciparum single infection was detected in 46%, while 38% had P. vivax, 11% mixed infections with P. falciparum and P. vivax, and 5% P. malariae. Compared to PCR, microscopy had sensitivity of 29% and specificity of 98%, while the RDT had sensitivity of 24% and specificity of 99%. Conclusions High malaria prevalence was identified by PCR in this cohort. Routine diagnostic methods had low sensitivity compared to PCR. The results suggest that malaria is underdiagnosed in rural India. However, low parasitaemia controlled by immunity may constitute a proportion of PCR positive cases, which calls for awareness of the fact that other pathogens could be responsible for the febrile disease in submicroscopic malaria. PMID:27389396

  9. Incidence of Severe Malaria Syndromes and Status of Immune Responses among Khat Chewer Malaria Patients in Ethiopia

    PubMed Central

    Ketema, Tsige

    2015-01-01

    Although more emphasis has been given to the genetic and environmental factors that determine host vulnerability to malaria, other factors that might have a crucial role in burdening the disease have not been evaluated yet. Therefore, this study was designed to assess the effect of khat chewing on the incidence of severe malaria syndromes and immune responses during malaria infection in an area where the two problems co-exist. Clinical, physical, demographic, hematological, biochemical and immunological data were collected from Plasmodium falciparum mono-infected malaria patients (age ≥ 10 years) seeking medication in Halaba Kulito and Jimma Health Centers. In addition, incidences of severe malaria symptoms were assessed. The data were analyzed using SPSS (version 20) software. Prevalence of current khat chewer malaria patients was 57.38% (95%CI =53-61.56%). Malaria symptoms such as hyperpyrexia, prostration and hyperparasitemia were significantly lower (P<0.05) among khat chewer malaria patients. However, relative risk to jaundice and renal failure were significantly higher (P<0.05) in khat chewers than in non-khat chewer malaria patients. Longer duration of khat use was positively associated with incidence of anemia. IgM and IgG antibody titers were significantly higher (P<0.05) among khat chewer malaria patients than among malaria positive non-chewers. Although levels of IgG subclasses in malaria patients did not show significant differences (P>0.05), IgG3 antibody was significantly higher (P<0.001) among khat chewer malaria patients. Moreover, IgM, IgG, IgG1and IgG3 antibodies had significant negative association (P<0.001) with parasite burden and clinical manifestations of severe malaria symptoms, but not with severe anemia and hypoglycemia. Additionally, a significant increment (P<0.05) in CD4+ T-lymphocyte population was observed among khat users. Khat might be an important risk factor for incidence of some severe malaria complications. Nevertheless, it

  10. Magneto immunoassays for Plasmodium falciparum histidine-rich protein 2 related to malaria based on magnetic nanoparticles.

    PubMed

    Castilho, M de Souza; Laube, T; Yamanaka, H; Alegret, S; Pividori, M I

    2011-07-15

    Magneto immunoassay-based strategies for the detection of Plasmodium falciparum histidine-rich protein 2 (HRP2) related to malaria are described for the first time by using magnetic micro- and nanoparticles. The covalent immobilization of a commercial monoclonal antibody toward the HRP2 protein in magnetic beads and nanoparticles was evaluated and compared. The immunological reaction for the protein HRP2 was successfully performed in a sandwich assay on magnetic micro- and nanoparticles by using a second monoclonal antibody labeled with the enzyme, horseradish peroxidase (HRP). Then, the modified magnetic particles were easily captured by a magneto sensor made of graphite-epoxy composite (m-GEC) which was also used as the transducer for the electrochemical detection. The performance of the immunoassay-based strategy with the electrochemical magneto immunosensors was successfully evaluated and compared with a novel magneto-ELISA based on optical detection using spiked serum samples. Improved sensitivity was obtained when using 300 nm magnetic nanoparticles in both cases. The electrochemical magneto immunosensor coupled with magnetic nanoparticles have shown better analytical performance in terms of limit of detection (0.36 ng mL(-1)), which is much lower than the LOD reported by other methods. Moreover, at a low level of HRP2 concentration of 31.0 ng mL(-1), a signal of 15.30 μA was reached with a cutoff value of 0.34 μA, giving a clear positive result with a non-specific adsorption ratio of 51. Due to the high sensitivity, this novel strategy offers great promise for rapid, simple, cost-effective, and on-site detection of falciparum malaria disease in patients, but also to screen out at-risk blood samples for prevention of transfusion-transmitted malaria.

  11. Functional consequences of perturbing polyamine metabolism in the malaria parasite, Plasmodium falciparum.

    PubMed

    Clark, K; Niemand, J; Reeksting, S; Smit, S; van Brummelen, A C; Williams, M; Louw, A I; Birkholtz, L

    2010-02-01

    Inhibition of polyamine biosynthesis and/or the perturbation of polyamine functionality have been exploited with success against parasitic diseases such as Trypanosoma infections. However, when the classical polyamine biosynthesis inhibitor, alpha-difluoromethylornithine, is used against the human malaria parasite, Plasmodium falciparum, it results in only a cytostatic growth arrest. Polyamine metabolism in this parasite has unique properties not shared by any other organism. These include the bifunctional arrangement of the catalytic decarboxylases and an apparent absence of the typical polyamine interconversion pathways implying different mechanisms for the regulation of polyamine homeostasis that includes the uptake of exogenous polyamines at least in vitro. These properties make polyamine metabolism an enticing drug target in P. falciparum provided that the physiological and functional consequences of polyamine metabolism perturbation are understood. This review highlights our current understanding of the biological consequences of inhibition of the biosynthetic enzymes in the polyamine pathway in P. falciparum as revealed by several global analytical approaches. Ultimately, the evidence suggests that polyamine metabolism in P. falciparum is a validated drug target worth exploiting. PMID:19997948

  12. Clinical Variation of Plasmodium falciparum eba-175, ama-1, and msp-3 Genotypes in Young Children Living in a Seasonally High Malaria Transmission Setting in Burkina Faso.

    PubMed

    Soulama, Issiaka; Sermé, Samuel S; Bougouma, Edith C; Diarra, Amidou; Tiono, Alfred B; Ouedraogo, Alphonse; Konate, Amadou T; Nebie, Issa; Sirima, Sodiomon B

    2015-01-01

    The association between P. falciparum eba-175, ama-1, and msp-3 polymorphism in the pathogenicity of malaria disease was investigated. We therefore compared the prevalence of different alleles between symptomatic and asymptomatic malarial children under five years of age living in Burkina Faso. Blood filter papers were collected during the 2008 malaria transmission season from 228 symptomatic and 199 asymptomatic children under five years of age. All patients were living in the rural area of Saponé at about 50 km from Ouagadougou, the capital city of Burkina Faso. P. falciparum parasite DNA was extracted using QIAGEN kits and the alleles diversity was assessed by a nested PCR. PCR products were then digested by restriction enzymes based on already described polymorphic regions of the eba-175, ama-1, and msp-3 genes. The individual alleles eba-175_FCR3 and msp-3_K1 frequencies were statistically higher (p < 0.0001) in the asymptomatic group compared to the symptomatic ones. No statistically significant difference was noted in the prevalence of ama-1-3D7, ama-1-K1, and ama-1-HB3 genotypes between the two groups (p > 0.05). The comparative analysis of P. falciparum genotypes indicated that the polymorphism in eba-175 and msp-3 genotypes varied between asymptomatic and symptomatic clinical groups and may contribute to the pathogenesis of malaria. PMID:26634149

  13. Contrasting Transmission Dynamics of Co-endemic Plasmodium vivax and P. falciparum: Implications for Malaria Control and Elimination

    PubMed Central

    Noviyanti, Rintis; Coutrier, Farah; Utami, Retno A. S.; Trimarsanto, Hidayat; Tirta, Yusrifar K.; Trianty, Leily; Kusuma, Andreas; Sutanto, Inge; Kosasih, Ayleen; Kusriastuti, Rita; Hawley, William A.; Laihad, Ferdinand; Lobo, Neil; Marfurt, Jutta; Clark, Taane G.; Price, Ric N.; Auburn, Sarah

    2015-01-01

    Background Outside of Africa, P. falciparum and P. vivax usually coexist. In such co-endemic regions, successful malaria control programs have a greater impact on reducing falciparum malaria, resulting in P. vivax becoming the predominant species of infection. Adding to the challenges of elimination, the dormant liver stage complicates efforts to monitor the impact of ongoing interventions against P. vivax. We investigated molecular approaches to inform the respective transmission dynamics of P. falciparum and P. vivax and how these could help to prioritize public health interventions. Methodology/ Principal Findings Genotype data generated at 8 and 9 microsatellite loci were analysed in 168 P. falciparum and 166 P. vivax isolates, respectively, from four co-endemic sites in Indonesia (Bangka, Kalimantan, Sumba and West Timor). Measures of diversity, linkage disequilibrium (LD) and population structure were used to gauge the transmission dynamics of each species in each setting. Marked differences were observed in the diversity and population structure of P. vivax versus P. falciparum. In Bangka, Kalimantan and Timor, P. falciparum diversity was low, and LD patterns were consistent with unstable, epidemic transmission, amenable to targeted intervention. In contrast, P. vivax diversity was higher and transmission appeared more stable. Population differentiation was lower in P. vivax versus P. falciparum, suggesting that the hypnozoite reservoir might play an important role in sustaining local transmission and facilitating the spread of P. vivax infections in different endemic settings. P. vivax polyclonality varied with local endemicity, demonstrating potential utility in informing on transmission intensity in this species. Conclusions/ Significance Molecular approaches can provide important information on malaria transmission that is not readily available from traditional epidemiological measures. Elucidation of the transmission dynamics circulating in a given

  14. Within-host competition and drug resistance in the human malaria parasite Plasmodium falciparum.

    PubMed

    Bushman, Mary; Morton, Lindsay; Duah, Nancy; Quashie, Neils; Abuaku, Benjamin; Koram, Kwadwo A; Dimbu, Pedro Rafael; Plucinski, Mateusz; Gutman, Julie; Lyaruu, Peter; Kachur, S Patrick; de Roode, Jacobus C; Udhayakumar, Venkatachalam

    2016-03-16

    Infections with the malaria parasite Plasmodium falciparum typically comprise multiple strains, especially in high-transmission areas where infectious mosquito bites occur frequently. However, little is known about the dynamics of mixed-strain infections, particularly whether strains sharing a host compete or grow independently. Competition between drug-sensitive and drug-resistant strains, if it occurs, could be a crucial determinant of the spread of resistance. We analysed 1341 P. falciparum infections in children from Angola, Ghana and Tanzania and found compelling evidence for competition in mixed-strain infections: overall parasite density did not increase with additional strains, and densities of individual chloroquine-sensitive (CQS) and chloroquine-resistant (CQR) strains were reduced in the presence of competitors. We also found that CQR strains exhibited low densities compared with CQS strains (in the absence of chloroquine), which may underlie observed declines of chloroquine resistance in many countries following retirement of chloroquine as a first-line therapy. Our observations support a key role for within-host competition in the evolution of drug-resistant malaria. Malaria control and resistance-management efforts in high-transmission regions may be significantly aided or hindered by the effects of competition in mixed-strain infections. Consideration of within-host dynamics may spur development of novel strategies to minimize resistance while maximizing the benefits of control measures.

  15. Within-host competition and drug resistance in the human malaria parasite Plasmodium falciparum.

    PubMed

    Bushman, Mary; Morton, Lindsay; Duah, Nancy; Quashie, Neils; Abuaku, Benjamin; Koram, Kwadwo A; Dimbu, Pedro Rafael; Plucinski, Mateusz; Gutman, Julie; Lyaruu, Peter; Kachur, S Patrick; de Roode, Jacobus C; Udhayakumar, Venkatachalam

    2016-03-16

    Infections with the malaria parasite Plasmodium falciparum typically comprise multiple strains, especially in high-transmission areas where infectious mosquito bites occur frequently. However, little is known about the dynamics of mixed-strain infections, particularly whether strains sharing a host compete or grow independently. Competition between drug-sensitive and drug-resistant strains, if it occurs, could be a crucial determinant of the spread of resistance. We analysed 1341 P. falciparum infections in children from Angola, Ghana and Tanzania and found compelling evidence for competition in mixed-strain infections: overall parasite density did not increase with additional strains, and densities of individual chloroquine-sensitive (CQS) and chloroquine-resistant (CQR) strains were reduced in the presence of competitors. We also found that CQR strains exhibited low densities compared with CQS strains (in the absence of chloroquine), which may underlie observed declines of chloroquine resistance in many countries following retirement of chloroquine as a first-line therapy. Our observations support a key role for within-host competition in the evolution of drug-resistant malaria. Malaria control and resistance-management efforts in high-transmission regions may be significantly aided or hindered by the effects of competition in mixed-strain infections. Consideration of within-host dynamics may spur development of novel strategies to minimize resistance while maximizing the benefits of control measures. PMID:26984625

  16. Mitochondrial genes support a common origin of rodent malaria parasites and Plasmodium falciparum's relatives infecting great apes

    PubMed Central

    2011-01-01

    Background Plasmodium falciparum is responsible for the most acute form of human malaria. Most recent studies demonstrate that it belongs to a monophyletic lineage specialized in the infection of great ape hosts. Several other Plasmodium species cause human malaria. They all belong to another distinct lineage of parasites which infect a wider range of primate species. All known mammalian malaria parasites appear to be monophyletic. Their clade includes the two previous distinct lineages of parasites of primates and great apes, one lineage of rodent parasites, and presumably Hepatocystis species. Plasmodium falciparum and great ape parasites are commonly thought to be the sister-group of all other mammal-infecting malaria parasites. However, some studies supported contradictory origins and found parasites of great apes to be closer to those of rodents, or to those of other primates. Results To distinguish between these mutually exclusive hypotheses on the origin of Plasmodium falciparum and its great ape infecting relatives, we performed a comprehensive phylogenetic analysis based on a data set of three mitochondrial genes from 33 to 84 malaria parasites. We showed that malarial mitochondrial genes have evolved slowly and are compositionally homogeneous. We estimated their phylogenetic relationships using Bayesian and maximum-likelihood methods. Inferred trees were checked for their robustness to the (i) site selection, (ii) assumptions of various probabilistic models, and (iii) taxon sampling. Our results robustly support a common ancestry of rodent parasites and Plasmodium falciparum's relatives infecting great apes. Conclusions Our results refute the most common view of the origin of great ape malaria parasites, and instead demonstrate the robustness of a less well-established phylogenetic hypothesis, under which Plasmodium falciparum and its relatives infecting great apes are closely related to rodent parasites. This study sheds light on the evolutionary history

  17. Characterization of class II apurinic/apyrimidinic endonuclease activities in the human malaria parasite, Plasmodium falciparum.

    PubMed Central

    Haltiwanger, B M; Karpinich, N O; Taraschi, T F

    2000-01-01

    We have reported that the human malaria parasite, Plasmodium falciparum, repairs apurinic/apyrimidinic (AP) sites on DNA by a long-patch base excision repair (BER) pathway. This biology is different from that in mammalian cells, which predominantly repair AP sites by a DNA-polymerase-beta-dependent, one-nucleotide patch BER pathway. As a starting point for the identification and biochemical characterization of the enzymes involved in the parasite DNA BER pathway, we chose characterization of the AP endonuclease activity in a P. falciparum cell-free lysate. Evidence is provided for the presence of class II, Mg(2+)-dependent and independent AP endonucleases in the parasite lysate. The investigation of the processing of AP sites in Plasmodium will provide new information about long-patch BER pathways; if they are different from those in the human host they might provide a new target for anti-malarial chemotherapy. PMID:10600642

  18. Epidemic of Plasmodium falciparum malaria involving substandard antimalarial drugs, Pakistan, 2003.

    PubMed

    Leslie, Toby; Kaur, Harpakash; Mohammed, Nasir; Kolaczinski, Kate; Ord, Rosalynn L; Rowland, Mark

    2009-11-01

    Because of instability in eastern Afghanistan, new refugees crossed into the federally administered tribal areas of northwestern Pakistan in 2002. In 2003, we investigated an epidemic of Plasmodium falciparum malaria in 1 of the camps. Incidence was 100.4 cases/1,000 person-years; in other nearby camps it was only 2.1/1,000 person-years. Anopheline mosquitoes were found despite an earlier spray campaign. Documented clinical failures at the basic health unit prompted a drug resistance survey of locally manufactured sulfadoxine-pyrimethamine used for routine treatment. The in vivo failure rate was 28.5%. PCR analysis of the P. falciparum dihydrofolate reductase and dihyropteroate synthase genes showed no mutations associated with clinical failure. However, chemical analysis of the drug showed that it was substandard. As global incidence decreases and epidemics become more of a threat, enhanced quality assurance of control interventions is essential. PMID:19891862

  19. Epidemic of Plasmodium falciparum Malaria Involving Substandard Antimalarial Drugs, Pakistan, 2003

    PubMed Central

    Kaur, Harpakash; Mohammed, Nasir; Kolaczinski, Kate; Ord, Rosalynn L.; Rowland, Mark

    2009-01-01

    Because of instability in eastern Afghanistan, new refugees crossed into the federally administered tribal areas of northwestern Pakistan in 2002. In 2003, we investigated an epidemic of Plasmodium falciparum malaria in 1 of the camps. Incidence was 100.4 cases/1,000 person-years; in other nearby camps it was only 2.1/1,000 person-years. Anopheline mosquitoes were found despite an earlier spray campaign. Documented clinical failures at the basic health unit prompted a drug resistance survey of locally manufactured sulfadoxine-pyrimethamine used for routine treatment. The in vivo failure rate was 28.5%. PCR analysis of the P. falciparum dihydrofolate reductase and dihyropteroate synthase genes showed no mutations associated with clinical failure. However, chemical analysis of the drug showed that it was substandard. As global incidence decreases and epidemics become more of a threat, enhanced quality assurance of control interventions is essential. PMID:19891862

  20. Haemoglobin-E in the presence of oxidative substances from fava bean may be protective against Plasmodium falciparum malaria.

    PubMed

    Kitayaporn, D; Nelson, K E; Charoenlarp, P; Pholpothi, T

    1992-01-01

    A case-control study was carried out at a community hospital in eastern Thailand in order to study the association between haemoglobin E and Plasmodium falciparum malaria; 271 P. falciparum cases and 271 controls were enrolled. After adjusting for age, sex, time since last malaria attack, history of mosquito net use, and history of fava bean consumption in the previous month, neither heterozygous nor homozygous haemoglobin E provided significant protection against P. falciparum infection, with odds ratios (OR) = 0.91 (95% confidence limits = 0.61, 1.36) and 0.78 (0.34, 1.82) respectively when compared to persons with haemoglobin A who were not consumers of fava beans. However, haemoglobin E carriers who ate fava beans were significantly protected against P. falciparum malaria with OR = 0.26 (0.09, 0.76) and OR = 0.001 (0.00, 1120.59) for subjects with heterozygous and homozygous haemoglobin E, respectively. The study suggests a possible synergistic protective effect of haemoglobin E on the risk of P. falciparum malaria in subjects who have consumed fava beans.

  1. Haemoglobin-E in the presence of oxidative substances from fava bean may be protective against Plasmodium falciparum malaria.

    PubMed

    Kitayaporn, D; Nelson, K E; Charoenlarp, P; Pholpothi, T

    1992-01-01

    A case-control study was carried out at a community hospital in eastern Thailand in order to study the association between haemoglobin E and Plasmodium falciparum malaria; 271 P. falciparum cases and 271 controls were enrolled. After adjusting for age, sex, time since last malaria attack, history of mosquito net use, and history of fava bean consumption in the previous month, neither heterozygous nor homozygous haemoglobin E provided significant protection against P. falciparum infection, with odds ratios (OR) = 0.91 (95% confidence limits = 0.61, 1.36) and 0.78 (0.34, 1.82) respectively when compared to persons with haemoglobin A who were not consumers of fava beans. However, haemoglobin E carriers who ate fava beans were significantly protected against P. falciparum malaria with OR = 0.26 (0.09, 0.76) and OR = 0.001 (0.00, 1120.59) for subjects with heterozygous and homozygous haemoglobin E, respectively. The study suggests a possible synergistic protective effect of haemoglobin E on the risk of P. falciparum malaria in subjects who have consumed fava beans. PMID:1412643

  2. Characteristics of Travel-Related Severe Plasmodium vivax and Plasmodium falciparum Malaria in Individuals Hospitalized at a Tertiary Referral Center in Lima, Peru.

    PubMed

    Llanos-Chea, Fiorella; Martínez, Dalila; Rosas, Angel; Samalvides, Frine; Vinetz, Joseph M; Llanos-Cuentas, Alejandro

    2015-12-01

    Severe Plasmodium falciparum malaria is uncommon in South America. Lima, Peru, while not endemic for malaria, is home to specialized centers for infectious diseases that admit and manage patients with severe malaria (SM), all of whom contracted infection during travel. This retrospective study describes severe travel-related malaria in individuals admitted to one tertiary care referral hospital in Lima, Peru; severity was classified based on criteria published by the World Health Organization in 2000. Data were abstracted from medical records of patients with SM admitted to Hospital Nacional Cayetano Heredia from 2006 to 2011. Of 33 SM cases with complete clinical data, the mean age was 39 years and the male/female ratio was 2.8. Most cases were contracted in known endemic regions within Peru: Amazonia (47%), the central jungle (18%), and the northern coast (12%); cases were also found in five (15%) travelers returning from Africa. Plasmodium vivax was most commonly identified (71%) among the severe infections, followed by P. falciparum (18%); mixed infections composed 11% of the group. Among the criteria of severity, jaundice was most common (58%), followed by severe thrombocytopenia (47%), hyperpyrexia (32%), and shock (15%). Plasmodium vivax mono-infection predominated as the etiology of SM in cases acquired in Peru.

  3. Optimizing Intradermal Administration of Cryopreserved Plasmodium falciparum Sporozoites in Controlled Human Malaria Infection

    PubMed Central

    Lyke, Kirsten E.; Laurens, Matthew B.; Strauss, Kathy; Adams, Matthew; Billingsley, Peter F.; James, Eric; Manoj, Anita; Chakravarty, Sumana; Plowe, Christopher V.; Li, Ming Lin; Ruben, Adam; Edelman, Robert; Green, Michael; Dube, Tina J.; Kim Lee Sim, B.; Hoffman, Stephen L.

    2015-01-01

    Controlled human malaria infection (CHMI) is a powerful tool to evaluate malaria vaccine and prophylactic drug efficacy. Until recently CHMI was only carried out by the bite of infected mosquitoes. A parenteral method of CHMI would standardize Plasmodium falciparum sporozoite (PfSPZ) administration, eliminate the need for expensive challenge facility infrastructure, and allow for use of many P. falciparum strains. Recently, intradermal (ID) injection of aseptic, purified, cryopreserved PfSPZ was shown to induce P. falciparum malaria; however, 100% infection rates were not achieved by ID injection. To optimize ID PfSPZ dosing so as to achieve 100% infection, 30 adults aged 18–45 years were randomized to one of six groups composed of five volunteers each. The parameters of dose (1 × 104 versus 5 × 104 PfSPZ total dose per volunteer), number of injections (two versus eight), and aliquot volume per ID injection (10 μL versus 50 μL) were studied. Three groups attained 100% infection: 1 × 104 PfSPZ in 50 μL/2 doses, 1 × 104 PfSPZ in 10 μL/2 doses, and 5 × 104 PfSPZ in 10 μL/8 doses. The group that received 5 × 104 PfSPZ total dose in eight 10 μL injections had a 100% infection rate and the shortest prepatent period (mean of 12.7 days), approaching the prepatent period for the current CHMI standard of five infected mosquitoes. PMID:26416102

  4. Optimizing Intradermal Administration of Cryopreserved Plasmodium falciparum Sporozoites in Controlled Human Malaria Infection.

    PubMed

    Lyke, Kirsten E; Laurens, Matthew B; Strauss, Kathy; Adams, Matthew; Billingsley, Peter F; James, Eric; Manoj, Anita; Chakravarty, Sumana; Plowe, Christopher V; Li, Ming Lin; Ruben, Adam; Edelman, Robert; Green, Michael; Dube, Tina J; Sim, B Kim Lee; Hoffman, Stephen L

    2015-12-01

    Controlled human malaria infection (CHMI) is a powerful tool to evaluate malaria vaccine and prophylactic drug efficacy. Until recently CHMI was only carried out by the bite of infected mosquitoes. A parenteral method of CHMI would standardize Plasmodium falciparum sporozoite (PfSPZ) administration, eliminate the need for expensive challenge facility infrastructure, and allow for use of many P. falciparum strains. Recently, intradermal (ID) injection of aseptic, purified, cryopreserved PfSPZ was shown to induce P. falciparum malaria; however, 100% infection rates were not achieved by ID injection. To optimize ID PfSPZ dosing so as to achieve 100% infection, 30 adults aged 18-45 years were randomized to one of six groups composed of five volunteers each. The parameters of dose (1 × 10(4) versus 5 × 10(4) PfSPZ total dose per volunteer), number of injections (two versus eight), and aliquot volume per ID injection (10 μL versus 50 μL) were studied. Three groups attained 100% infection: 1 × 10(4) PfSPZ in 50 μL/2 doses, 1 × 10(4) PfSPZ in 10 μL/2 doses, and 5 × 10(4) PfSPZ in 10 μL/8 doses. The group that received 5 × 10(4) PfSPZ total dose in eight 10 μL injections had a 100% infection rate and the shortest prepatent period (mean of 12.7 days), approaching the prepatent period for the current CHMI standard of five infected mosquitoes.

  5. Transport of lactate and pyruvate in the intraerythrocytic malaria parasite, Plasmodium falciparum.

    PubMed Central

    Elliott, J L; Saliba, K J; Kirk, K

    2001-01-01

    The mature, intraerythrocytic form of the human malaria parasite, Plasmodium falciparum, is reliant on glycolysis for its energetic requirements. It produces large quantities of lactic acid, which have to be removed from the parasite's cytosol to maintain the cell's integrity and metabolic viability. Here we show that the monocarboxylates lactate and pyruvate are both transported across the parasite's plasma membrane via a H(+)/monocarboxylate symport process that is saturable and inhibited by the bioflavonoid phloretin. The results provide direct evidence for the presence at the parasite surface of a H(+)-coupled monocarboxylate transporter with features in common with members of the MCT (monocarboxylate transporter) family of higher eukaryotes. PMID:11311136

  6. Population genetic study of Plasmodium falciparum parasites pertaining to dhps gene sequence in malaria endemic areas of Assam.

    PubMed

    Sharma, J; Dutta, P; Khan, S A

    2015-01-01

    Plasmodium falciparum malaria parasite had developed resistance to almost all the currently used antimalarial drugs. The purpose of the study was to come across the genetic distances in P. falciparum dhps gene sequences circulating in Assam. A partial fragment of P. falciparum dhps gene containing major single nucleotide polymorphisms associated with sulphadoxine resistance were amplified and sequenced. Thereafter specific bioinformatics tools like BioEdit v7.0.9, ClustalW in Mega 5, DnaSP version v.5.10.01 etc were used for the analysis. A total of 100 P. falciparum positive cases in different malaria endemic areas of Assam were included for the study. Based upon the mutation analysis, a total of seven different P. falciparum dhps genotypes were observed with five variable sites. Maximum five haplotypes were found in the P. falciparum isolates from Jorhat district of Assam. Four polymorphic sites were observed in the P. falciparum dhps gene sequences in Karbi Anglong, NC Hills, Chirang and Jorhat whereas the isolates from other study areas had three polymorphic sites. A statistically significant positive value of Tajima's D were observed among the P. falciparum field isolates in Assam indicating that there is an excess of intermediate frequency alleles and can result from population bottlenecks, structure and/or balancing selection. Extensive gene flow took place among the P. falciparum population of Jorhat with Sivasagar, Chirang with Sivasagar and Chirang with Karbi Anglong. However, large genetic differentiation was observed among the P. falciparum isolates of NC Hills with Lakhimpur, Tinsukia, Dibrugarh and Golaghat and also the parasite population of Karbi Anglong with Lakhimpur and Tinsukia signifying little gene flow among the population. This finding has shown that mutant Pfdhps gene associated with sulphadoxine resistance is circulating in Assam. It is believed that, the parasite population may have undergone high level of breeding.

  7. Defining the In Vivo Phenotype of Artemisinin-Resistant Falciparum Malaria: A Modelling Approach

    PubMed Central

    White, Lisa J.; Flegg, Jennifer A.; Phyo, Aung Pyae; Wiladpai-ngern, Ja Hser; Bethell, Delia; Plowe, Christopher; Anderson, Tim; Nkhoma, Standwell; Nair, Shalini; Tripura, Rupam; Stepniewska, Kasia; Pan-Ngum, Wirichada; Silamut, Kamolrat; Cooper, Ben S.; Lubell, Yoel; Ashley, Elizabeth A.; Nguon, Chea; Nosten, François; White, Nicholas J.; Dondorp, Arjen M.

    2015-01-01

    Background Artemisinin-resistant falciparum malaria has emerged in Southeast Asia, posing a major threat to malaria control. It is characterised by delayed asexual-stage parasite clearance, which is the reference comparator for the molecular marker ‘Kelch 13’ and in vitro sensitivity tests. However, current cut-off values denoting slow clearance based on the proportion of individuals remaining parasitaemic on the third day of treatment ('day-3'), or on peripheral blood parasite half-life, are not well supported. We here explore the parasite clearance distributions in an area of artemisinin resistance with the aim refining the in vivo phenotypic definitions. Methods and Findings Data from 1,518 patients on the Thai-Myanmar and Thai-Cambodian borders with parasite half-life assessments after artesunate treatment were analysed. Half-lives followed a bimodal distribution. A statistical approach was developed to infer the characteristics of the component distributions and their relative contribution to the composite mixture. A model representing two parasite subpopulations with geometric mean (IQR) parasite half-lives of 3.0 (2.4-3.9) hours and 6.50 (5.7-7.4) hours was consistent with the data. For individual patients, the parasite half-life provided a predicted likelihood of an artemisinin-resistant infection which depends on the population prevalence of resistance in that area. Consequently, a half-life where the probability is 0.5 varied between 3.5 and 5.5 hours. Using this model, the current 'day-3' cut-off value of 10% predicts the potential presence of artemisinin-resistant infections in most but not all scenarios. These findings are relevant to the low-transmission setting of Southeast Asia. Generalisation to a high transmission setting as in regions of Sub-Saharan Africa will need additional evaluation. Conclusions Characterisation of overlapping distributions of parasite half-lives provides quantitative insight into the relationship between parasite

  8. Genome-wide mapping of DNA methylation in the human malaria parasite Plasmodium falciparum

    PubMed Central

    Ponts, Nadia; Fu, Lijuan; Harris, Elena Y.; Zhang, Jing; Chung, Duk-Won D.; Cervantes, Michael C.; Prudhomme, Jacques; Atanasova-Penichon, Vessela; Zehraoui, Enric; Bunnik, Evelien; Rodrigues, Elisandra M.; Lonardi, Stefano; Hicks, Glenn R.; Wang, Yinsheng; Le Roch, Karine G.

    2014-01-01

    SUMMARY Cytosine DNA methylation is an epigenetic mark in most eukaryotic cells that regulates numerous processes, including gene expression and stress responses. We performed a genome-wide analysis of DNA methylation in the human malaria parasite Plasmodium falciparum. We mapped the positions of methylated cytosines and identified a single functional DNA methyltransferase, PfDNMT, that may mediate these genomic modifications. These analyses revealed that the malaria genome is asymmetrically methylated, in which only one DNA strand is methylated, and shares common features with undifferentiated plant and mammalian cells. Notably, core promoters are hypomethylated and transcript levels correlate with intra-exonic methylation. Additionally, there are sharp methylation transitions at nucleosome and exon-intron boundaries. These data suggest that DNA methylation could regulate virulence gene expression and transcription elongation. Furthermore, the broad range of action of DNA methylation and uniqueness of PfDNMT suggest that the methylation pathway is a potential target for anti-malarial strategies. PMID:24331467

  9. Large-scale growth of the Plasmodium falciparum malaria parasite in a wave bioreactor.

    PubMed

    Dalton, John P; Demanga, Corine G; Reiling, Sarah J; Wunderlich, Juliane; Eng, Jenny W L; Rohrbach, Petra

    2012-01-01

    We describe methods for the large-scale in vitro culturing of synchronous and asynchronous blood-stage Plasmodium falciparum parasites in sterile disposable plastic bioreactors controlled by wave-induced motion (wave bioreactor). These cultures perform better than static flask cultures in terms of preserving parasite cell cycle synchronicity and reducing the number of multiple-infected erythrocytes. The straight-forward methods described here will facilitate the large scale production of malaria parasites for antigen and organelle isolation and characterisation, for the high throughput screening of compound libraries with whole cells or extracts, and the development of live- or whole-cell malaria vaccines under good manufacturing practice compliant standards. PMID:22326740

  10. Targeting of a Transporter to the Outer Apicoplast Membrane in the Human Malaria Parasite Plasmodium falciparum

    PubMed Central

    Goodman, Christopher D.; McFadden, Geoffrey I.

    2016-01-01

    Apicoplasts are vestigial plastids in apicomplexan parasites like Plasmodium, the causative agent of malaria. Apicomplexan parasites are dependant on their apicoplasts for synthesis of various molecules that they are unable to scavenge in sufficient quantity from their host, which makes apicoplasts attractive drug targets. Proteins known as plastid phosphate translocators (pPTs) are embedded in the outer apicoplast membrane and are responsible for the import of carbon, energy and reducing power to drive anabolic synthesis in the organelle. We investigated how a pPT is targeted into the outer apicoplast membrane of the human malaria parasite P. falciparum. We showed that a transmembrane domain is likely to act as a recessed signal anchor to direct the protein into the endomembrane system, and that a tyrosine in the cytosolic N-terminus of the protein is essential for targeting, but one or more, as yet unidentified, factors are also essential to direct the protein into the outer apicoplast membrane. PMID:27442138

  11. Targeting of a Transporter to the Outer Apicoplast Membrane in the Human Malaria Parasite Plasmodium falciparum.

    PubMed

    Lim, Liting; Sayers, Claire P; Goodman, Christopher D; McFadden, Geoffrey I

    2016-01-01

    Apicoplasts are vestigial plastids in apicomplexan parasites like Plasmodium, the causative agent of malaria. Apicomplexan parasites are dependant on their apicoplasts for synthesis of various molecules that they are unable to scavenge in sufficient quantity from their host, which makes apicoplasts attractive drug targets. Proteins known as plastid phosphate translocators (pPTs) are embedded in the outer apicoplast membrane and are responsible for the import of carbon, energy and reducing power to drive anabolic synthesis in the organelle. We investigated how a pPT is targeted into the outer apicoplast membrane of the human malaria parasite P. falciparum. We showed that a transmembrane domain is likely to act as a recessed signal anchor to direct the protein into the endomembrane system, and that a tyrosine in the cytosolic N-terminus of the protein is essential for targeting, but one or more, as yet unidentified, factors are also essential to direct the protein into the outer apicoplast membrane. PMID:27442138

  12. Spontaneous Subdural Empyema Following a High-Parasitemia Falciparum Infection in a 58-Year-Old Female From a Malaria-Endemic Region: A Case Report.

    PubMed

    Pallangyo, Pedro; Lyimo, Frederick; Nicholaus, Paulina; Kain, Ulimbakisya; Janabi, Mohamed

    2016-01-01

    Malaria remains a significant public health problem of the tropical world. Falciparum malaria is most prevalent in the sub-Saharan African region, which harbors about 90% of all malaria cases and fatalities globally. Infection by the falciparum species often manifests with a spectrum of multi-organ complications (eg, cerebral malaria), some of which are life-threatening. Spontaneous subdural empyema is a very rare complication of cerebral malaria that portends a very poor prognosis unless diagnosed and treated promptly. We report a case of spontaneous subdural empyema in a 58-year-old woman from Tanzania who presented with high-grade fever, decreased urine output, and altered sensorium. PMID:27635411

  13. Spontaneous Subdural Empyema Following a High-Parasitemia Falciparum Infection in a 58-Year-Old Female From a Malaria-Endemic Region

    PubMed Central

    Pallangyo, Pedro; Lyimo, Frederick; Nicholaus, Paulina; Kain, Ulimbakisya; Janabi, Mohamed

    2016-01-01

    Malaria remains a significant public health problem of the tropical world. Falciparum malaria is most prevalent in the sub-Saharan African region, which harbors about 90% of all malaria cases and fatalities globally. Infection by the falciparum species often manifests with a spectrum of multi-organ complications (eg, cerebral malaria), some of which are life-threatening. Spontaneous subdural empyema is a very rare complication of cerebral malaria that portends a very poor prognosis unless diagnosed and treated promptly. We report a case of spontaneous subdural empyema in a 58-year-old woman from Tanzania who presented with high-grade fever, decreased urine output, and altered sensorium.

  14. Spontaneous Subdural Empyema Following a High-Parasitemia Falciparum Infection in a 58-Year-Old Female From a Malaria-Endemic Region

    PubMed Central

    Pallangyo, Pedro; Lyimo, Frederick; Nicholaus, Paulina; Kain, Ulimbakisya; Janabi, Mohamed

    2016-01-01

    Malaria remains a significant public health problem of the tropical world. Falciparum malaria is most prevalent in the sub-Saharan African region, which harbors about 90% of all malaria cases and fatalities globally. Infection by the falciparum species often manifests with a spectrum of multi-organ complications (eg, cerebral malaria), some of which are life-threatening. Spontaneous subdural empyema is a very rare complication of cerebral malaria that portends a very poor prognosis unless diagnosed and treated promptly. We report a case of spontaneous subdural empyema in a 58-year-old woman from Tanzania who presented with high-grade fever, decreased urine output, and altered sensorium. PMID:27635411

  15. Plasmodium falciparum signal peptide peptidase cleaves malaria heat shock protein 101 (HSP101). Implications for gametocytogenesis

    SciTech Connect

    Baldwin, Michael; Russo, Crystal; Li, Xuerong; Chishti, Athar H.

    2014-08-08

    Highlights: • PfSPP is an ER resident protease. • PfSPP is expressed both as a monomer and dimer. • The signal peptide of HSP101 is the first known substrate of PfSPP. • Reduced PfSPP activity may significantly affect ER homeostasis. - Abstract: Previously we described the identification of a Plasmodium falciparum signal peptide peptidase (PfSPP) functioning at the blood stage of malaria infection. Our studies also demonstrated that mammalian SPP inhibitors prevent malaria parasite growth at the late-ring/early trophozoite stage of intra-erythrocytic development. Consistent with its role in development, we tested the hypothesis that PfSPP functions at the endoplasmic reticulum of P.falciparum where it cleaves membrane-bound signal peptides generated following the enzyme activity of signal peptidase. The localization of PfSPP to the endoplasmic reticulum was confirmed by immunofluorescence microscopy and immunogold electron microscopy. Biochemical analysis indicated the existence of monomer and dimer forms of PfSPP in the parasite lysate. A comprehensive bioinformatics screen identified several candidate PfSPP substrates in the parasite genome. Using an established transfection based in vivo luminescence assay, malaria heat shock protein 101 (HSP101) was identified as a substrate of PfSPP, and partial inhibition of PfSPP correlated with the emergence of gametocytes. This finding unveils the first known substrate of PfSPP, and provides new perspectives for the function of intra-membrane proteolysis at the erythrocyte stage of malaria parasite life cycle.

  16. Gametocyte clearance dynamics following oral artesunate treatment of uncomplicated falciparum malaria in Malian children.

    PubMed

    Djimde, Abdoulaye A; Maiga, Amelia W; Ouologuem, Dinkorma; Fofana, Bakary; Sagara, Issaka; Dembele, Demba; Toure, Sekou; Sanogo, Kassim; Dama, Souleymane; Sidibe, Bakary; Doumbo, Ogobara K

    2016-01-01

    Artemisinin-based combination therapies decrease Plasmodium gametocyte carriage. However, the role of artesunate in monotherapy in vivo, the mechanisms involved, and the utility of gametocyte carriage as a potential tool for the surveillance of antimalarial resistance are poorly understood. In 2010-2011, we conducted an open-label, prospective efficacy study of artesunate as monotherapy in children 1-10 years of age with uncomplicated falciparum malaria in Bougoula-Hameau, Mali. Standard oral doses of artesunate were administered for 7 days and patients were followed up for 28 days. The data were compared to a similar study conducted in 2002-2004. Of 100 children enrolled in the 2010-2011 study, 92 were analyzed and compared to 217 children enrolled in the 2002-2004 study. The proportion of gametocyte carriers was unchanged at the end of treatment (23% at baseline vs. 24% on day 7, p = 1.0) and did not significantly decline until day 21 of follow-up (23% vs. 6%, p = 0.003). The mean gametocyte density at inclusion remained unchanged at the end of treatment (12 gametocytes/μL vs. 16 gametocytes/μL, p = 0.6). Overall, 46% of the 71 initial non-carriers had gametocytes detected by day 7. Similar results were found in the 2002-2004 study. In both studies, although gametocyte carriage significantly decreased by the end of the 28-day follow-up, artesunate did not clear mature gametocytes during treatment and did not prevent the appearance of new stage V gametocytes as assessed by light microscopy. Baseline gametocyte carriage was significantly higher 6 years after the deployment of artemisinin-based combination therapies in this setting. PMID:26839003

  17. Gametocyte clearance dynamics following oral artesunate treatment of uncomplicated falciparum malaria in Malian children

    PubMed Central

    Djimde, Abdoulaye A.; Maiga, Amelia W.; Ouologuem, Dinkorma; Fofana, Bakary; Sagara, Issaka; Dembele, Demba; Toure, Sekou; Sanogo, Kassim; Dama, Souleymane; Sidibe, Bakary; Doumbo, Ogobara K.

    2016-01-01

    Artemisinin-based combination therapies decrease Plasmodium gametocyte carriage. However, the role of artesunate in monotherapy in vivo, the mechanisms involved, and the utility of gametocyte carriage as a potential tool for the surveillance of antimalarial resistance are poorly understood. In 2010–2011, we conducted an open-label, prospective efficacy study of artesunate as monotherapy in children 1–10 years of age with uncomplicated falciparum malaria in Bougoula-Hameau, Mali. Standard oral doses of artesunate were administered for 7 days and patients were followed up for 28 days. The data were compared to a similar study conducted in 2002–2004. Of 100 children enrolled in the 2010–2011 study, 92 were analyzed and compared to 217 children enrolled in the 2002–2004 study. The proportion of gametocyte carriers was unchanged at the end of treatment (23% at baseline vs. 24% on day 7, p = 1.0) and did not significantly decline until day 21 of follow-up (23% vs. 6%, p = 0.003). The mean gametocyte density at inclusion remained unchanged at the end of treatment (12 gametocytes/μL vs. 16 gametocytes/μL, p = 0.6). Overall, 46% of the 71 initial non-carriers had gametocytes detected by day 7. Similar results were found in the 2002–2004 study. In both studies, although gametocyte carriage significantly decreased by the end of the 28-day follow-up, artesunate did not clear mature gametocytes during treatment and did not prevent the appearance of new stage V gametocytes as assessed by light microscopy. Baseline gametocyte carriage was significantly higher 6 years after the deployment of artemisinin-based combination therapies in this setting. PMID:26839003

  18. Does artesunate prolong the electrocardiograph QT interval in patients with severe malaria?

    PubMed

    Maude, Richard J; Plewes, Katherine; Faiz, M Abul; Hanson, Josh; Charunwatthana, Prakaykaew; Lee, Sue J; Tärning, Joel; Yunus, Emran Bin; Hoque, M Gofranul; Hasan, Mahatab Uddin; Hossain, Amir; Lindegardh, Niklas; Day, Nicholas P J; White, Nicholas J; Dondorp, Arjen M

    2009-01-01

    Several antimalarials can cause significant prolongation of the electrocardiograph QT interval, which can be associated with an increased risk of potentially lethal ventricular arrhythmias. High doses of artemether and artemotil have been associated with QT prolongation in dogs, raising the possibility of a class effect with the artemisinin derivatives. Serial electrocardiograms were recorded, and QTc interval was calculated before and after administration of artesunate by intravenous injection in patients with severe falciparum malaria in Bangladesh. Of 21 adult patients with severe malaria enrolled, 8 (38%) died. The mean QTc interval was unaffected by bolus intravenous artesunate (2.4 mg/kg). In two patients, the QTc interval exceeded 0.5 seconds, but in both cases, an alternative explanation was plausible. No effect was observed on the JTc or PR interval, QRS width, blood pressure, or heart rate. Intravenous artesunate does not have significant cardiovascular effects in patients with severe falciparum malaria.

  19. Reduced Parasite Burden in Children with Falciparum Malaria and Bacteremia Coinfections: Role of Mediators of Inflammation.

    PubMed

    Davenport, Gregory C; Hittner, James B; Otieno, Vincent; Karim, Zachary; Mukundan, Harshini; Fenimore, Paul W; Hengartner, Nicolas W; McMahon, Benjamin H; Kempaiah, Prakasha; Ong'echa, John M; Perkins, Douglas J

    2016-01-01

    Bacteremia and malaria coinfection is a common and life-threatening condition in children residing in sub-Saharan Africa. We previously showed that coinfection with Gram negative (G[-]) enteric Bacilli and Plasmodium falciparum (Pf[+]) was associated with reduced high-density parasitemia (HDP, >10,000 parasites/μL), enhanced respiratory distress, and severe anemia. Since inflammatory mediators are largely unexplored in such coinfections, circulating cytokines were determined in four groups of children (n = 206, aged <3 yrs): healthy; Pf[+] alone; G[-] coinfected; and G[+] coinfected. Staphylococcus aureus and non-Typhi Salmonella were the most frequently isolated G[+] and G[-] organisms, respectively. Coinfected children, particularly those with G[-] pathogens, had lower parasite burden (peripheral and geometric mean parasitemia and HDP). In addition, both coinfected groups had increased IL-4, IL-5, IL-7, IL-12, IL-15, IL-17, IFN-γ, and IFN-α and decreased TNF-α relative to malaria alone. Children with G[-] coinfection had higher IL-1β and IL-1Ra and lower IL-10 than the Pf[+] group and higher IFN-γ than the G[+] group. To determine how the immune response to malaria regulates parasitemia, cytokine production was investigated with a multiple mediation model. Cytokines with the greatest mediational impact on parasitemia were IL-4, IL-10, IL-12, and IFN-γ. Results here suggest that enhanced immune activation, especially in G[-] coinfected children, acts to reduce malaria parasite burden. PMID:27418744

  20. Efficacy and pharmacokinetics of a new intrarectal quinine formulation in children with Plasmodium falciparum malaria

    PubMed Central

    BARENNES, H.; PUSSARD, E.; MAHAMAN SANI, A.; CLAVIER, F.; KAHIATANI, F.; GRANIC, G.; HENZEL, D.; RAVINET, L.; VERDIER, F.

    1996-01-01

    1Three groups of seven children aged 2–14 years with acute uncomplicated Plasmodium falciparum malaria received 12.8 mg kg−1 quinine gluconate by the intrarectal route (new cream formulation) or 8 mg kg−1 Quinimax (a Cinchona alkaloid combination) by the intramuscular or intravenous (4 h infusion) route every 8 h for 3 days. Clinical and parasitological status was similar in the three groups at enrolment. 2At 36 h, body temperature of all children of the three groups was returned to normal and remained so until day 7. 3The decrease in parasitaemia did not differ between the three groups and the time required for a 50% fall in parasitaemia relative to baseline was 12.3±5.4, 18.2±6.1 and 14.5±4.2 h in the intrarectal, intramuscular and intravenous treatment groups, respectively. Parasitaemia expressed as a percentage of initial values was not significantly different in the three groups after 48 h of treatment (7.4±16.0, 4.1±4.2 and 2.2±3.8% in the intrarectal, intramuscular and intravenous treatment groups, respectively). All the patients were aparasitaemic by day 7. 4The tolerability of the three treatments was good; in particular, no rectal irritation was reported with the cream formulation. 5The tmax occurred later after intrarectal (4.1±2.4 h) and intravenous infusion (3.8±0.5 h) than after intramuscular injection (1.6±1.3 h) (P=0.02). Cmax was lower with the intrarectal (3.0±1.0 mg l−1) and intramuscular routes (3.2±0.7 mg l−1) than with the intravenous route (5.1±1.4 mg l−1) (P=0.003). Areas under the curve (AUC(0, 8 h)) were smaller with the intrarectal (17.0±7 mg l−1 h) and intramuscular routes (19.4±4.8 mg l−1 h) than with the intravenous route (27.8±8.2 mg l−1 h) (P=0.02). The approximate bioavailability of intrarectal quinine from 0 to 8 h was 36%vs intravenous quinine and 51%vs intramuscular quinine. 6The good tolerability and efficacy of this new intrarectal quinine formulation

  1. Alterations in Plasmodium falciparum Genetic Structure Two Years after Increased Malaria Control Efforts in Western Kenya

    PubMed Central

    Vardo-Zalik, Anne M.; Zhou, Guofa; Zhong, Daibin; Afrane, Yaw A.; Githeko, Andrew K.; Yan, Guiyun

    2013-01-01

    The impact of malaria intervention measures (insecticide-treated net use and artemisinin combination therapy) on malaria genetics was investigated at two sites in western Kenya: an endemic lowland and an epidemic highland. The genetic structure of the parasite population was assessed by using microsatellites, and the prevalence of drug-resistant mutations was examined by using the polymerase chain reaction–restriction fragment length polymorphism method. Two years after intervention, genetic diversity remained high in both populations. A significant decrease in the prevalence of quintuple mutations conferring resistance to sulfadoxine-pyrimethamine was detected in both populations, but the mutation prevalence at codon 1246 of the Plasmodium falciparum multidrug resistance 1 gene had increased in the highland population. The decrease in sulfadoxine-pyrimethamine–resistant mutants is encouraging, but the increase in P. falciparum multidrug resistance 1 gene mutations is worrisome because these mutations are linked to resistance to other antimalarial drugs. In addition, the high level of genetic diversity observed after intervention suggests transmission is still high in each population. PMID:23166196

  2. Molecular basis of differential resistance to cycloguanil and pyrimethamine in Plasmodium falciparum malaria.

    PubMed Central

    Peterson, D S; Milhous, W K; Wellems, T E

    1990-01-01

    Proguanil and pyrimethamine are antifolate drugs with distinct chemical structures that are used commonly in the prophylaxis and treatment of Plasmodium falciparum malaria. Clinical reports and field studies have suggested that some parasites refractory to proguanil can be treated with pyrimethamine, and vice versa. Analysis of the P. falciparum dihydrofolate reductase (DHFR) from different parasites reveals the structural basis for differential susceptibility to these antifolate drugs. Parasites harboring a pair of point mutations from Ala-16 to Val-16 and from Ser-108 to Thr-108 are resistant to cycloguanil (the active metabolite of proguanil) but not to pyrimethamine. A single Asn-108 mutation, on the other hand, confers resistance to pyrimethamine with only a moderate decrease in susceptibility to cycloguanil. Significant cross-resistance to both drugs occurs in parasites having mutations that include Ser-108----Asn-108 and Ile-164----Leu-164. These results reflect the distinct structures of pyrimethamine and cycloguanil and suggest fine differences in binding within the active site cavity of DHFR. Alternative inhibitors, used alone or in combination, may be effective against some strains of cycloguanil- or pyrimethamine-resistant malaria. Images PMID:2183222

  3. DNA repair mechanisms and their biological roles in the malaria parasite Plasmodium falciparum.

    PubMed

    Lee, Andrew H; Symington, Lorraine S; Fidock, David A

    2014-09-01

    Research into the complex genetic underpinnings of the malaria parasite Plasmodium falciparum is entering a new era with the arrival of site-specific genome engineering. Previously restricted only to model systems but now expanded to most laboratory organisms, and even to humans for experimental gene therapy studies, this technology allows researchers to rapidly generate previously unattainable genetic modifications. This technological advance is dependent on DNA double-strand break repair (DSBR), specifically homologous recombination in the case of Plasmodium. Our understanding of DSBR in malaria parasites, however, is based largely on assumptions and knowledge taken from other model systems, which do not always hold true in Plasmodium. Here we describe the causes of double-strand breaks, the mechanisms of DSBR, and the differences between model systems and P. falciparum. These mechanisms drive basic parasite functions, such as meiosis, antigen diversification, and copy number variation, and allow the parasite to continually evolve in the contexts of host immune pressure and drug selection. Finally, we discuss the new technologies that leverage DSBR mechanisms to accelerate genetic investigations into this global infectious pathogen.

  4. Development and Application of a Simple Plaque Assay for the Human Malaria Parasite Plasmodium falciparum

    PubMed Central

    Thomas, James A.; Collins, Christine R.; Das, Sujaan; Hackett, Fiona; Graindorge, Arnault; Bell, Donald; Deu, Edgar; Blackman, Michael J.

    2016-01-01

    Malaria is caused by an obligate intracellular protozoan parasite that replicates within and destroys erythrocytes. Asexual blood stages of the causative agent of the most virulent form of human malaria, Plasmodium falciparum, can be cultivated indefinitely in vitro in human erythrocytes, facilitating experimental analysis of parasite cell biology, biochemistry and genetics. However, efforts to improve understanding of the basic biology of this important pathogen and to develop urgently required new antimalarial drugs and vaccines, suffer from a paucity of basic research tools. This includes a simple means of quantifying the effects of drugs, antibodies and gene modifications on parasite fitness and replication rates. Here we describe the development and validation of an extremely simple, robust plaque assay that can be used to visualise parasite replication and resulting host erythrocyte destruction at the level of clonal parasite populations. We demonstrate applications of the plaque assay by using it for the phenotypic characterisation of two P. falciparum conditional mutants displaying reduced fitness in vitro. PMID:27332706

  5. Geographic differentiation of polymorphism in the Plasmodium falciparum malaria vaccine candidate gene SERA5.

    PubMed

    Tanabe, Kazuyuki; Arisue, Nobuko; Palacpac, Nirianne M Q; Yagi, Masanori; Tougan, Takahiro; Honma, Hajime; Ferreira, Marcelo U; Färnert, Anna; Björkman, Anders; Kaneko, Akira; Nakamura, Masatoshi; Hirayama, Kenji; Mita, Toshihiro; Horii, Toshihiro

    2012-02-21

    SERA5 is regarded as a promising malaria vaccine candidate of the most virulent human malaria parasite Plasmodium falciparum. SERA5 is a 120 kDa abundantly expressed blood-stage protein containing a papain-like protease. Since substantial polymorphism in blood-stage vaccine candidates may potentially limit their efficacy, it is imperative to fully investigate polymorphism of the SERA5 gene (sera5). In this study, we performed evolutionary and population genetic analysis of sera5. The level of inter-species divergence (kS=0.076) between P. falciparum and Plasmodium reichenowi, a closely related chimpanzee malaria parasite is comparable to that of housekeeping protein genes. A signature of purifying selection was detected in the proenzyme and enzyme domains. Analysis of 445 near full-length P. falciparum sera5 sequences from nine countries in Africa, Southeast Asia, Oceania and South America revealed extensive variations in the number of octamer repeat (OR) and serine repeat (SR) regions as well as substantial level of single nucleotide polymorphism (SNP) in non-repeat regions (2562 bp). Remarkably, a 14 amino acid sequence of SERA5 (amino acids 59-72) that is known to be the in vitro target of parasite growth inhibitory antibodies was found to be perfectly conserved in all 445 worldwide isolates of P. falciparum evaluated. Unlike other major vaccine target antigen genes such as merozoite surface protein-1, apical membrane antigen-1 or circumsporozoite protein, no strong evidence for positive selection was detected for SNPs in the non-repeat regions of sera5. A biased geographical distribution was observed in SNPs as well as in the haplotypes of the sera5 OR and SR regions. In Africa, OR- and SR-haplotypes with low frequency (<5%) and SNPs with minor allele frequency (<5%) were abundant and were mostly continent-specific. Consistently, significant genetic differentiation, assessed by the Wright's fixation index (Fst) of inter-population variance in allele frequencies

  6. An open randomized controlled trial to compare the efficacy of two fixed dose combinations of artemesinin based combinations for uncomplicated falciparum malaria in Bangladesh.

    PubMed

    Samad, R; Rahman, M R; Yunus, E B; Hussain, M A; Arif, S M; Islam, M N; Hafiz, S A M M A; Hossain, M M; Faiz, M A

    2013-12-01

    National Malaria Control Program (NMCP) of Bangladesh has introduced Artemisinin Based Combination (ACT), Coartem(R) (Artemether-Lumefantrine (AL), fixed dose combination, in the confirmed cases of uncomplicated P. falciparum malaria since 2004. Despite the reduction of mortality due to malaria, the development and spread of anti-malarial drug resistance wordwide posing a threat to the health services and will make it difficult to control malaria in Bangladesh in future. We need to have an alternative to Coartem which could be Artesunate-amodiaquine (AA) in a fixed dose combination (FDC), a cheaper altenative not yet evidenced to be effective and safe to our population. In this study we compared the efficacy and safety of Artemether + Lumefantrene (FDC, Coartem) with Artesunate +Amodiaquine tablets (100/270 mg FDC) for the treatment of uncomplicated P. falciparum malaria in three high risk multi-drug resistant malaria prevalent areas of Bangladesh. It was an open label randomized controlled trial conducted between December 2008 and November 2009 in 4 upazillas in patients over the age 12 to 60 years diagnosed as a case of uncomplicated P. falciparum malaria. The outcome of the cases were measured as clinical response, parasitological response, defervescence time and parasite clearance time. Drug safety was assessed by comparing the adverse events. A total of 252 cases were randomized to receive Artesunate + Amodiaquine (AA group, 147 cases) and Artemether + Lumefantrene (AL group, 106 cases), one lost to follow up at day 28 in AA group. The distribution of the cases was comparable by age, sex and study sites. Treatment success' response was observed 100% in the AL group and AA group had 99%, two failures with AA were late treatment failures and the difference was not statistically significant (p > .1). The parasitological sensitive (S) response was observed in 97% of cases in AL group and 95% in the AA group, and was not a statistically significant difference

  7. The Clp Chaperones and Proteases of the Human Malaria Parasite Plasmodium falciparum

    SciTech Connect

    Bakkouri, Majida El; Pow, Andre; Mulichak, Anne; Cheung, Kevin L.Y.; Artz, Jennifer D.; Amani, Mehrnaz; Fell, Stuart; de Koning-Ward, Tania F.; Goodman, C. Dean; McFadden, Geoffrey I.; Ortega, Joaquin; Hui, Raymond; Houry, Walid A.

    2015-02-09

    The Clp chaperones and proteases play an important role in protein homeostasis in the cell. They are highly conserved across prokaryotes and found also in the mitochondria of eukaryotes and the chloroplasts of plants. They function mainly in the disaggregation, unfolding and degradation of native as well as misfolded proteins. Here, we provide a comprehensive analysis of the Clp chaperones and proteases in the human malaria parasite Plasmodium falciparum. The parasite contains four Clp ATPases, which we term PfClpB1, PfClpB2, PfClpC and PfClpM. One PfClpP, the proteolytic subunit, and one PfClpR, which is an inactive version of the protease, were also identified. Expression of all Clp chaperones and proteases was confirmed in blood-stage parasites. The proteins were localized to the apicoplast, a non-photosynthetic organelle that accommodates several important metabolic pathways in P. falciparum, with the exception of PfClpB2 (also known as Hsp101), which was found in the parasitophorous vacuole. Both PfClpP and PfClpR form mostly homoheptameric rings as observed by size-exclusion chromatography, analytical ultracentrifugation and electron microscopy. The X-ray structure of PfClpP showed the protein as a compacted tetradecamer similar to that observed for Streptococcus pneumoniae and Mycobacterium tuberculosis ClpPs. Our data suggest the presence of a ClpCRP complex in the apicoplast of P. falciparum.

  8. Use of Peptide Nucleic Acids to Manipulate Gene Expression in the Malaria Parasite Plasmodium falciparum

    PubMed Central

    Naik, Shankar; Yavin, Eylon; Dzikowski, Ron

    2014-01-01

    One of the major concerns in treating malaria by conventional small drug molecules is the rapid emergence of drug resistance. Specific silencing of essential genes by antisense oliogomers has been proposed as an alternative approach that may result in antimalarial activity which is not associated with drug resistance. In addition, such an approach could be an important biological tool for studying many genes' function by reverse genetics. Here we present a novel methodology of using peptide nucleic acids (PNAs) as a useful tool for gene silencing in Plasmodium falciparum. PNAs, designed as specific antisense molecules, were conjugated to a cell penetrating peptide (CPP); namely, octa-D-lysine via the C-terminus, to allow facile delivery through cell membranes. PNAs added to P. falciparum cultures were found exclusively in infected erythrocytes and were eventually localized in nuclei of the parasites at all stages of intra erythrocytic development. We show that these PNAs specifically down regulated both a stably expressed transgene as well as an endogenous essential gene, which significantly reduced parasites' viability. This study paves the way for a simple approach to silence a variety of P. falciparum genes as means of deciphering their function and potentially to develop highly specific and potent antimalarial agents. PMID:24466246

  9. Parasite Sequestration in Plasmodium falciparum Malaria: Spleen and Antibody Modulation of Cytoadherence of Infected Erythrocytes

    NASA Astrophysics Data System (ADS)

    David, Peter H.; Hommel, Marcel; Miller, Louis H.; Udeinya, Iroka J.; Oligino, Lynette D.

    1983-08-01

    Sequestration, the adherence of infected erythrocytes containing late developmental stages of the parasite (trophozoites and schizonts) to the endothelium of capillaries and venules, is characteristic of Plasmodium falciparum infections. We have studied two host factors, the spleen and antibody, that influence sequestration of P. falciparum in the squirrel monkey. Sequestration of trophozoite/schizont-infected erythrocytes that occurs in intact animals is reduced in splenectomized animals; in vitro, when infected blood is incubated with monolayers of human melanoma cells, trophozoite/schizont-infected erythrocytes from intact animals but not from splenectomized animals bind to the melanoma cells. The switch in cytoadherence characteristics of the infected erythrocytes from nonbinding to binding occurs with a cloned parasite. Immune serum can inhibit and reverse in vitro binding to melanoma cells of infected erythrocytes from intact animals. Similarly, antibody can reverse in vivo sequestration as shown by the appearance of trophozoite/schizont-infected erythrocytes in the peripheral blood of an intact animal after inoculation with immune serum. These results indicate that the spleen modulates the expression of parasite alterations of the infected erythrocyte membrane responsible for sequestration and suggest that the prevention and reversal of sequestration could be one of the effector mechanisms involved in antibody-mediated protection against P. falciparum malaria.

  10. A genomic glimpse of aminoacyl-tRNA synthetases in malaria parasite Plasmodium falciparum

    PubMed Central

    2009-01-01

    Background Plasmodium parasites are causative agents of malaria which affects >500 million people and claims ~2 million lives annually. The completion of Plasmodium genome sequencing and availability of PlasmoDB database has provided a platform for systematic study of parasite genome. Aminoacyl-tRNA synthetases (aaRSs) are pivotal enzymes for protein translation and other vital cellular processes. We report an extensive analysis of the Plasmodium falciparum genome to identify and classify aaRSs in this organism. Results Using various computational and bioinformatics tools, we have identified 37 aaRSs in P. falciparum. Our key observations are: (i) fraction of proteome dedicated to aaRSs in P. falciparum is very high compared to many other organisms; (ii) 23 out of 37 Pf-aaRS sequences contain signal peptides possibly directing them to different cellular organelles; (iii) expression profiles of Pf-aaRSs vary considerably at various life cycle stages of the parasite; (iv) several PfaaRSs posses very unusual domain architectures; (v) phylogenetic analyses reveal evolutionary relatedness of several parasite aaRSs to bacterial and plants aaRSs; (vi) three dimensional structural modelling has provided insights which could be exploited in inhibitor discovery against parasite aaRSs. Conclusion We have identified 37 Pf-aaRSs based on our bioinformatics analysis. Our data reveal several unique attributes in this protein family. We have annotated all 37 Pf-aaRSs based on predicted localization, phylogenetics, domain architectures and their overall protein expression profiles. The sets of distinct features elaborated in this work will provide a platform for experimental dissection of this family of enzymes, possibly for the discovery of novel drugs against malaria. PMID:20042123

  11. On the diversity of malaria parasites in African apes and the origin of Plasmodium falciparum from Bonobos.

    PubMed

    Krief, Sabrina; Escalante, Ananias A; Pacheco, M Andreina; Mugisha, Lawrence; André, Claudine; Halbwax, Michel; Fischer, Anne; Krief, Jean-Michel; Kasenene, John M; Crandfield, Mike; Cornejo, Omar E; Chavatte, Jean-Marc; Lin, Clara; Letourneur, Franck; Grüner, Anne Charlotte; McCutchan, Thomas F; Rénia, Laurent; Snounou, Georges

    2010-02-12

    The origin of Plasmodium falciparum, the etiological agent of the most dangerous forms of human malaria, remains controversial. Although investigations of homologous parasites in African Apes are crucial to resolve this issue, studies have been restricted to a chimpanzee parasite related to P. falciparum, P. reichenowi, for which a single isolate was available until very recently. Using PCR amplification, we detected Plasmodium parasites in blood samples from 18 of 91 individuals of the genus Pan, including six chimpanzees (three Pan troglodytes troglodytes, three Pan t. schweinfurthii) and twelve bonobos (Pan paniscus). We obtained sequences of the parasites' mitochondrial genomes and/or from two nuclear genes from 14 samples. In addition to P. reichenowi, three other hitherto unknown lineages were found in the chimpanzees. One is related to P. vivax and two to P. falciparum that are likely to belong to distinct species. In the bonobos we found P. falciparum parasites whose mitochondrial genomes indicated that they were distinct from those present in humans, and another parasite lineage related to P. malariae. Phylogenetic analyses based on this diverse set of Plasmodium parasites in African Apes shed new light on the evolutionary history of P. falciparum. The data suggested that P. falciparum did not originate from P. reichenowi of chimpanzees (Pan troglodytes), but rather evolved in bonobos (Pan paniscus), from which it subsequently colonized humans by a host-switch. Finally, our data and that of others indicated that chimpanzees and bonobos maintain malaria parasites, to which humans are susceptible, a factor of some relevance to the renewed efforts to eradicate malaria.

  12. Open-label trial on efficacy of artemether/lumefantrine against the uncomplicated Plasmodium falciparum malaria in Metema district, Northwestern Ethiopia

    PubMed Central

    Wudneh, Feven; Assefa, Ashenafi; Nega, Desalegn; Mohammed, Hussien; Solomon, Hiwot; Kebede, Tadesse; Woyessa, Adugna; Assefa, Yibeltal; Kebede, Amha; Kassa, Moges

    2016-01-01

    Purpose Following the increased Plasmodium falciparum resistance to chloroquine and sulfadoxine/pyrimethamine, Ethiopia adopted artemether/lumefantrine (AL) as the first-line treatment for uncomplicated P. falciparum in 2004. According to the recommendation of the World Health Organization, this study was carried out for regular monitoring of the efficacy of AL in treating the uncomplicated P. falciparum malaria in Metema district, Gondar Zone, Northwest Ethiopia. Patients and methods This is a one-arm prospective 28-day in vivo therapeutic efficacy study among the uncomplicated P. falciparum malaria patients aged 6 months and older. The study was conducted from October 2014 to January 2015, based on the revised World Health Organization protocol of 2009 for surveillance of antimalarial drug therapeutic efficacy study. Standard six-dose regimen of AL was given twice daily for 3 days, and then the treatment outcomes were assessed on days 0, 1, 2, 3, 7, 14, 21, 28, and any other unscheduled day for emergency cases. Results There were 91 study subjects enrolled in this study, of whom 80 study subjects completed the full follow-up schedules and showed adequate clinical and parasitological responses on day 28, with no major adverse event. Per protocol analysis, the unadjusted cure rate of Coartem® was 98.8% (95% confidence interval: 93.3%–100%) in the study area. Recurrence of one P. falciparum case was detected on day 28, with a late parasitological failure rate of 1.2%. No early treatment failure occurred. Complete parasite and fever clearance was observed on day 3. Gametocyte carriage was 4.4% at enrollment that cleared on day 21. Although the difference is statistically not significant, a slight increase in the level of mean hemoglobin from baseline to day 28 was observed. Conclusion The study showed high efficacy and tolerability of Coartem® against uncomplicated P. falciparum malaria, suggesting the continuation as a first-line drug in the study district

  13. Open-label trial on efficacy of artemether/lumefantrine against the uncomplicated Plasmodium falciparum malaria in Metema district, Northwestern Ethiopia

    PubMed Central

    Wudneh, Feven; Assefa, Ashenafi; Nega, Desalegn; Mohammed, Hussien; Solomon, Hiwot; Kebede, Tadesse; Woyessa, Adugna; Assefa, Yibeltal; Kebede, Amha; Kassa, Moges

    2016-01-01

    Purpose Following the increased Plasmodium falciparum resistance to chloroquine and sulfadoxine/pyrimethamine, Ethiopia adopted artemether/lumefantrine (AL) as the first-line treatment for uncomplicated P. falciparum in 2004. According to the recommendation of the World Health Organization, this study was carried out for regular monitoring of the efficacy of AL in treating the uncomplicated P. falciparum malaria in Metema district, Gondar Zone, Northwest Ethiopia. Patients and methods This is a one-arm prospective 28-day in vivo therapeutic efficacy study among the uncomplicated P. falciparum malaria patients aged 6 months and older. The study was conducted from October 2014 to January 2015, based on the revised World Health Organization protocol of 2009 for surveillance of antimalarial drug therapeutic efficacy study. Standard six-dose regimen of AL was given twice daily for 3 days, and then the treatment outcomes were assessed on days 0, 1, 2, 3, 7, 14, 21, 28, and any other unscheduled day for emergency cases. Results There were 91 study subjects enrolled in this study, of whom 80 study subjects completed the full follow-up schedules and showed adequate clinical and parasitological responses on day 28, with no major adverse event. Per protocol analysis, the unadjusted cure rate of Coartem® was 98.8% (95% confidence interval: 93.3%–100%) in the study area. Recurrence of one P. falciparum case was detected on day 28, with a late parasitological failure rate of 1.2%. No early treatment failure occurred. Complete parasite and fever clearance was observed on day 3. Gametocyte carriage was 4.4% at enrollment that cleared on day 21. Although the difference is statistically not significant, a slight increase in the level of mean hemoglobin from baseline to day 28 was observed. Conclusion The study showed high efficacy and tolerability of Coartem® against uncomplicated P. falciparum malaria, suggesting the continuation as a first-line drug in the study district

  14. Malaria antifolate resistance with contrasting Plasmodium falciparum dihydrofolate reductase (DHFR) polymorphisms in humans and Anopheles mosquitoes

    PubMed Central

    Mharakurwa, Sungano; Kumwenda, Taida; Mkulama, Mtawa A. P.; Musapa, Mulenga; Chishimba, Sandra; Shiff, Clive J.; Sullivan, David J.; Thuma, Philip E.; Liu, Kun; Agre, Peter

    2011-01-01

    Surveillance for drug-resistant parasites in human blood is a major effort in malaria control. Here we report contrasting antifolate resistance polymorphisms in Plasmodium falciparum when parasites in human blood were compared with parasites in Anopheles vector mosquitoes from sleeping huts in rural Zambia. DNA encoding P. falciparum dihydrofolate reductase (EC 1.5.1.3) was amplified by PCR with allele-specific restriction enzyme digestions. Markedly prevalent pyrimethamine-resistant mutants were evident in human P. falciparum infections—S108N (>90%), with N51I, C59R, and 108N+51I+59R triple mutants (30–80%). This resistance level may be from selection pressure due to decades of sulfadoxine/pyrimethamine use in the region. In contrast, cycloguanil-resistant mutants were detected in very low frequency in parasites from human blood samples—S108T (13%), with A16V and 108T+16V double mutants (∼4%). Surprisingly, pyrimethamine-resistant mutants were of very low prevalence (2–12%) in the midguts of Anopheles arabiensis vector mosquitoes, but cycloguanil-resistant mutants were highly prevalent—S108T (90%), with A16V and the 108T+16V double mutant (49–57%). Structural analysis of the dihydrofolate reductase by in silico modeling revealed a key difference in the enzyme within the NADPH binding pocket, predicting the S108N enzyme to have reduced stability but the S108T enzyme to have increased stability. We conclude that P. falciparum can bear highly host-specific drug-resistant polymorphisms, most likely reflecting different selective pressures found in humans and mosquitoes. Thus, it may be useful to sample both human and mosquito vector infections to accurately ascertain the epidemiological status of drug-resistant alleles. PMID:22065788

  15. Pattern of humoral immune response to Plasmodium falciparum blood stages in individuals presenting different clinical expressions of malaria

    PubMed Central

    Leoratti, Fabiana MS; Durlacher, Rui R; Lacerda, Marcus VG; Alecrim, Maria G; Ferreira, Antonio W; Sanchez, Maria CA; Moraes, Sandra L

    2008-01-01

    Background The development of protective immunity against malaria is slow and to be maintained, it requires exposure to multiple antigenic variants of malaria parasites and age-associated maturation of the immune system. Evidence that the protective immunity is associated with different classes and subclasses of antibodies reveals the importance of considering the quality of the response. In this study, we have evaluated the humoral immune response against Plasmodium falciparum blood stages of individuals naturally exposed to malaria who live in endemic areas of Brazil in order to assess the prevalence of different specific isotypes and their association with different malaria clinical expressions. Methods Different isotypes against P. falciparum blood stages, IgG, IgG1, IgG2, IgG3, IgG4, IgM, IgE and IgA, were determined by ELISA. The results were based on the analysis of different clinical expressions of malaria (complicated, uncomplicated and asymptomatic) and factors related to prior malaria exposure such as age and the number of previous clinical malaria attacks. The occurrence of the H131 polymorphism of the FcγIIA receptor was also investigated in part of the studied population. Results The highest levels of IgG, IgG1, IgG2 and IgG3 antibodies were observed in individuals with asymptomatic and uncomplicated malaria, while highest levels of IgG4, IgE and IgM antibodies were predominant among individuals with complicated malaria. Individuals reporting more than five previous clinical malaria attacks presented a predominance of IgG1, IgG2 and IgG3 antibodies, while IgM, IgA and IgE antibodies predominated among individuals reporting five or less previous clinical malaria attacks. Among individuals with uncomplicated and asymptomatic malaria, there was a predominance of high-avidity IgG, IgG1, IgG2 antibodies and low-avidity IgG3 antibodies. The H131 polymorphism was found in 44.4% of the individuals, and the highest IgG2 levels were observed among asymptomatic

  16. The multifunctional autophagy pathway in the human malaria parasite, Plasmodium falciparum.

    PubMed

    Cervantes, Serena; Bunnik, Evelien M; Saraf, Anita; Conner, Christopher M; Escalante, Aster; Sardiu, Mihaela E; Ponts, Nadia; Prudhomme, Jacques; Florens, Laurence; Le Roch, Karine G

    2014-01-01

    Autophagy is a catabolic pathway typically induced by nutrient starvation to recycle amino acids, but can also function in removing damaged organelles. In addition, this pathway plays a key role in eukaryotic development. To date, not much is known about the role of autophagy in apicomplexan parasites and more specifically in the human malaria parasite Plasmodium falciparum. Comparative genomic analysis has uncovered some, but not all, orthologs of autophagy-related (ATG) genes in the malaria parasite genome. Here, using a genome-wide in silico analysis, we confirmed that ATG genes whose products are required for vesicle expansion and completion are present, while genes involved in induction of autophagy and cargo packaging are mostly absent. We subsequently focused on the molecular and cellular function of P. falciparum ATG8 (PfATG8), an autophagosome membrane marker and key component of the autophagy pathway, throughout the parasite asexual and sexual erythrocytic stages. In this context, we showed that PfATG8 has a distinct and atypical role in parasite development. PfATG8 localized in the apicoplast and in vesicles throughout the cytosol during parasite development. Immunofluorescence assays of PfATG8 in apicoplast-minus parasites suggest that PfATG8 is involved in apicoplast biogenesis. Furthermore, treatment of parasite cultures with bafilomycin A 1 and chloroquine, both lysosomotropic agents that inhibit autophagosome and lysosome fusion, resulted in dramatic morphological changes of the apicoplast, and parasite death. Furthermore, deep proteomic analysis of components associated with PfATG8 indicated that it may possibly be involved in ribophagy and piecemeal microautophagy of the nucleus. Collectively, our data revealed the importance and specificity of the autophagy pathway in the malaria parasite and offer potential novel therapeutic strategies.

  17. Interethnic Differences in Antigen-Presenting Cell Activation and TLR Responses in Malian Children during Plasmodium falciparum Malaria

    PubMed Central

    Boström, Stéphanie; Dara, Victor; Traore, Boubacar; Dolo, Amagana; Doumbo, Ogobara; Varani, Stefania; Troye-Blomberg, Marita

    2011-01-01

    The Fulani ethnic group from West Africa is relatively better protected against Plasmodium falciparum malaria as compared to other sympatric ethnic groups, such as the Dogon. However, the mechanisms behind this lower susceptibility to malaria are largely unknown, particularly those concerning innate immunity. Antigen-presenting cells (APCs), and in particular dendritic cells (DCs) are important components of the innate and adaptive immune systems. Therefore, in this study we investigated whether APCs obtained from Fulani and Dogon children exhibited differences in terms of activation status and toll-like receptor (TLR) responses during malaria infection. Lower frequency and increased activation was observed in circulating plasmacytoid DCs and BDCA-3+ myeloid DCs of infected Fulani as compared to their uninfected counterparts. Conversely, a higher frequency and reduced activation was observed in the same DC subsets obtained from peripheral blood of P. falciparum-infected Dogon children as compared to their uninfected peers. Moreover, infected individuals of both ethnic groups exhibited higher percentages of both classical and inflammatory monocytes that were less activated as compared to their non-infected counterparts. In line with APC impairment during malaria infection, TLR4, TLR7 and TLR9 responses were strongly inhibited by P. falciparum infection in Dogon children, while no such TLR inhibition was observed in the Fulani children. Strikingly, the TLR-induced IFN-γ release was completely abolished in the Dogon undergoing infection while no difference was seen within infected and non-infected Fulani. Thus, P. falciparum infection is associated with altered activation status of important APC subsets and strongly inhibited TLR responses in peripheral blood of Dogon children. In contrast, P. falciparum induces DC activation and does not affect the innate response to specific TLR ligands in Fulani children. These findings suggest that DCs and TLR signalling may be

  18. Interethnic differences in antigen-presenting cell activation and TLR responses in Malian children during Plasmodium falciparum malaria.

    PubMed

    Arama, Charles; Giusti, Pablo; Boström, Stéphanie; Dara, Victor; Traore, Boubacar; Dolo, Amagana; Doumbo, Ogobara; Varani, Stefania; Troye-Blomberg, Marita

    2011-03-31

    The Fulani ethnic group from West Africa is relatively better protected against Plasmodium falciparum malaria as compared to other sympatric ethnic groups, such as the Dogon. However, the mechanisms behind this lower susceptibility to malaria are largely unknown, particularly those concerning innate immunity. Antigen-presenting cells (APCs), and in particular dendritic cells (DCs) are important components of the innate and adaptive immune systems. Therefore, in this study we investigated whether APCs obtained from Fulani and Dogon children exhibited differences in terms of activation status and toll-like receptor (TLR) responses during malaria infection. Lower frequency and increased activation was observed in circulating plasmacytoid DCs and BDCA-3+ myeloid DCs of infected Fulani as compared to their uninfected counterparts. Conversely, a higher frequency and reduced activation was observed in the same DC subsets obtained from peripheral blood of P. falciparum-infected Dogon children as compared to their uninfected peers. Moreover, infected individuals of both ethnic groups exhibited higher percentages of both classical and inflammatory monocytes that were less activated as compared to their non-infected counterparts. In line with APC impairment during malaria infection, TLR4, TLR7 and TLR9 responses were strongly inhibited by P. falciparum infection in Dogon children, while no such TLR inhibition was observed in the Fulani children. Strikingly, the TLR-induced IFN-γ release was completely abolished in the Dogon undergoing infection while no difference was seen within infected and non-infected Fulani. Thus, P. falciparum infection is associated with altered activation status of important APC subsets and strongly inhibited TLR responses in peripheral blood of Dogon children. In contrast, P. falciparum induces DC activation and does not affect the innate response to specific TLR ligands in Fulani children. These findings suggest that DCs and TLR signalling may be

  19. Maintenance of phenotypic diversity within a set of virulence encoding genes of the malaria parasite Plasmodium falciparum.

    PubMed

    Holding, Thomas; Recker, Mario

    2015-12-01

    Infection by the human malaria parasite Plasmodium falciparum results in a broad spectrum of clinical outcomes, ranging from severe and potentially life-threatening malaria to asymptomatic carriage. In a process of naturally acquired immunity, individuals living in malaria-endemic regions build up a level of clinical protection, which attenuates infection severity in an exposure-dependent manner. Underlying this shift in the immunoepidemiology as well as the observed range in malaria pathogenesis is the var multigene family and the phenotypic diversity embedded within. The var gene-encoded surface proteins Plasmodium falciparum erythrocyte membrane protein 1 mediate variant-specific binding of infected red blood cells to a diverse set of host receptors that has been linked to specific disease manifestations, including cerebral and pregnancy-associated malaria. Here, we show that cross-reactive immune responses, which minimize the within-host benefit of each additionally expressed gene during infection, can cause selection for maximum phenotypic diversity at the genome level. We further show that differential functional constraints on protein diversification stably maintain uneven ratios between phenotypic groups, in line with empirical observation. Our results thus suggest that the maintenance of phenotypic diversity within P. falciparum is driven by an evolutionary trade-off that optimizes between within-host parasite fitness and between-host selection pressure.

  20. Screening the Medicines for Malaria Venture "Malaria Box" against the Plasmodium falciparum aminopeptidases, M1, M17 and M18.

    PubMed

    Paiardini, Alessandro; Bamert, Rebecca S; Kannan-Sivaraman, Komagal; Drinkwater, Nyssa; Mistry, Shailesh N; Scammells, Peter J; McGowan, Sheena

    2015-01-01

    Malaria is a parasitic disease that remains a global health burden. The ability of the parasite to rapidly develop resistance to therapeutics drives an urgent need for the delivery of new drugs. The Medicines for Malaria Venture have compounds known for their antimalarial activity, but not necessarily the molecular targets. In this study, we assess the ability of the "MMV 400" compounds to inhibit the activity of three metalloaminopeptidases from Plasmodium falciparum, PfA-M1, PfA-M17 and PfM18 AAP. We have developed a multiplex assay system to allow rapid primary screening of compounds against all three metalloaminopeptidases, followed by detailed analysis of promising compounds. Our results show that there were no PfM18AAP inhibitors, whereas two moderate inhibitors of the neutral aminopeptidases PfA-M1 and PfA-M17 were identified. Further investigation through structure-activity relationship studies and molecular docking suggest that these compounds are competitive inhibitors with novel binding mechanisms, acting through either non-classical zinc coordination or independently of zinc binding altogether. Although it is unlikely that inhibition of PfA-M1 and/or PfA-M17 is the primary mechanism responsible for the antiplasmodial activity reported for these compounds, their detailed characterization, as presented in this work, pave the way for their further optimization as a novel class of dual PfA-M1/PfA-M17 inhibitors utilising non-classical zinc binding groups.

  1. Human population, urban settlement patterns and their impact on Plasmodium falciparum malaria endemicity

    PubMed Central

    Tatem, Andrew J; Guerra, Carlos A; Kabaria, Caroline W; Noor, Abdisalan M; Hay, Simon I

    2008-01-01

    Background The efficient allocation of financial resources for malaria control and the optimal distribution of appropriate interventions require accurate information on the geographic distribution of malaria risk and of the human populations it affects. Low population densities in rural areas and high population densities in urban areas can influence malaria transmission substantially. Here, the Malaria Atlas Project (MAP) global database of Plasmodium falciparum parasite rate (PfPR) surveys, medical intelligence and contemporary population surfaces are utilized to explore these relationships and other issues involved in combining malaria risk maps with those of human population distribution in order to define populations at risk more accurately. Methods First, an existing population surface was examined to determine if it was sufficiently detailed to be used reliably as a mask to identify areas of very low and very high population density as malaria free regions. Second, the potential of international travel and health guidelines (ITHGs) for identifying malaria free cities was examined. Third, the differences in PfPR values between surveys conducted in author-defined rural and urban areas were examined. Fourth, the ability of various global urban extent maps to reliably discriminate these author-based classifications of urban and rural in the PfPR database was investigated. Finally, the urban map that most accurately replicated the author-based classifications was analysed to examine the effects of urban classifications on PfPR values across the entire MAP database. Results Masks of zero population density excluded many non-zero PfPR surveys, indicating that the population surface was not detailed enough to define areas of zero transmission resulting from low population densities. In contrast, the ITHGs enabled the identification and mapping of 53 malaria free urban areas within endemic countries. Comparison of PfPR survey results showed significant differences

  2. Controlled Human Malaria Infections by Intradermal Injection of Cryopreserved Plasmodium falciparum Sporozoites

    PubMed Central

    Roestenberg, Meta; Bijker, Else M.; Sim, B. Kim Lee; Billingsley, Peter F.; James, Eric R.; Bastiaens, Guido J. H.; Teirlinck, Anne C.; Scholzen, Anja; Teelen, Karina; Arens, Theo; van der Ven, André J. A. M.; Gunasekera, Anusha; Chakravarty, Sumana; Velmurugan, Soundarapandian; Hermsen, Cornelus C.; Sauerwein, Robert W.; Hoffman, Stephen L.

    2013-01-01

    Controlled human malaria infection with sporozoites is a standardized and powerful tool for evaluation of malaria vaccine and drug efficacy but so far only applied by exposure to bites of Plasmodium falciparum (Pf)-infected mosquitoes. We assessed in an open label Phase 1 trial, infection after intradermal injection of respectively 2,500, 10,000, or 25,000 aseptic, purified, vialed, cryopreserved Pf sporozoites (PfSPZ) in three groups (N = 6/group) of healthy Dutch volunteers. Infection was safe and parasitemia developed in 15 of 18 volunteers (84%), 5 of 6 volunteers in each group. There were no differences between groups in time until parasitemia by microscopy or quantitative polymerase chain reaction, parasite kinetics, clinical symptoms, or laboratory values. This is the first successful infection by needle and syringe with PfSPZ manufactured in compliance with regulatory standards. After further optimization, the use of such PfSPZ may facilitate and accelerate clinical development of novel malaria drugs and vaccines. PMID:23149582

  3. Plasmodium falciparum serine repeat antigen 5 (SE36) as a malaria vaccine candidate.

    PubMed

    Palacpac, Nirianne Marie Q; Arisue, Nobuko; Tougan, Takahiro; Ishii, Ken J; Horii, Toshihiro

    2011-08-11

    A devastating disease spread by mosquitoes with high-efficiency, malaria imposes an enormous burden for which no licensed vaccine currently exists. Although the genome complexity of the parasite has made vaccine development tenuous, an effective malaria vaccine would be a valuable tool for control, elimination and eventual eradication. The Plasmodium serine repeat antigen 5 (SERA5) is an abundant asexual blood stage antigen that does not show any antigenic variation and exhibits limited polymorphism, making it a suitable vaccine candidate. Identified by comparing the IgG status of people in endemic areas with protective immunity and those with malaria symptoms, the vaccine potential of the N-terminal domain of Plasmodium falciparum SERA5 is also strongly supported by experimental data and immune responses both measured in vitro and in animal challenge models. The current understanding of SERA5 will be presented, particularly in relation to its path towards clinical development. The review highlights lessons learned and sorts out issues upon which further research efforts are needed. PMID:21718740

  4. Analysis of Antibodies Directed against Merozoite Surface Protein 1 of the Human Malaria Parasite Plasmodium falciparum

    PubMed Central

    Woehlbier, Ute; Epp, Christian; Kauth, Christian W.; Lutz, Rolf; Long, Carole A.; Coulibaly, Boubacar; Kouyaté, Bocar; Arevalo-Herrera, Myriam; Herrera, Sócrates; Bujard, Hermann

    2006-01-01

    The 190-kDa merozoite surface protein 1 (MSP-1) of Plasmodium falciparum, an essential component in the parasite's life cycle, is a primary candidate for a malaria vaccine. Rabbit antibodies elicited by the heterologously produced MSP-1 processing products p83, p30, p38, and p42, derived from strain 3D7, were analyzed for the potential to inhibit in vitro erythrocyte invasion by the parasite and parasite growth. Our data show that (i) epitopes recognized by antibodies, which inhibit parasite replication, are distributed throughout the entire MSP-1 molecule; (ii) when combined, antibodies specific for different regions of MSP-1 inhibit in a strictly additive manner; (iii) anti-MSP-1 antibodies interfere with erythrocyte invasion as well as with the intraerythrocytic growth of the parasite; and (iv) antibodies raised against MSP-1 of strain 3D7 strongly cross-inhibit replication of the heterologous strain FCB-1. Accordingly, anti-MSP-1 antibodies appear to be capable of interfering with parasite multiplication at more than one level. Since the overall immunogenicity profile of MSP-1 in rabbits closely resembles that found in sera of Aotus monkeys immunized with parasite-derived MSP-1 and of humans semi-immune to malaria from whom highly inhibiting antigen-specific antibodies were recovered, we consider the findings reported here to be relevant for the development of MSP-1-based vaccines against malaria. PMID:16428781

  5. Analysis of antibodies directed against merozoite surface protein 1 of the human malaria parasite Plasmodium falciparum.

    PubMed

    Woehlbier, Ute; Epp, Christian; Kauth, Christian W; Lutz, Rolf; Long, Carole A; Coulibaly, Boubacar; Kouyaté, Bocar; Arevalo-Herrera, Myriam; Herrera, Sócrates; Bujard, Hermann

    2006-02-01

    The 190-kDa merozoite surface protein 1 (MSP-1) of Plasmodium falciparum, an essential component in the parasite's life cycle, is a primary candidate for a malaria vaccine. Rabbit antibodies elicited by the heterologously produced MSP-1 processing products p83, p30, p38, and p42, derived from strain 3D7, were analyzed for the potential to inhibit in vitro erythrocyte invasion by the parasite and parasite growth. Our data show that (i) epitopes recognized by antibodies, which inhibit parasite replication, are distributed throughout the entire MSP-1 molecule; (ii) when combined, antibodies specific for different regions of MSP-1 inhibit in a strictly additive manner; (iii) anti-MSP-1 antibodies interfere with erythrocyte invasion as well as with the intraerythrocytic growth of the parasite; and (iv) antibodies raised against MSP-1 of strain 3D7 strongly cross-inhibit replication of the heterologous strain FCB-1. Accordingly, anti-MSP-1 antibodies appear to be capable of interfering with parasite multiplication at more than one level. Since the overall immunogenicity profile of MSP-1 in rabbits closely resembles that found in sera of Aotus monkeys immunized with parasite-derived MSP-1 and of humans semi-immune to malaria from whom highly inhibiting antigen-specific antibodies were recovered, we consider the findings reported here to be relevant for the development of MSP-1-based vaccines against malaria.

  6. Real-Time Imaging of the Intracellular Glutathione Redox Potential in the Malaria Parasite Plasmodium falciparum

    PubMed Central

    Kasozi, Denis; Mohring, Franziska; Rahlfs, Stefan; Meyer, Andreas J.; Becker, Katja

    2013-01-01

    In the malaria parasite Plasmodium falciparum, the cellular redox potential influences signaling events, antioxidant defense, and mechanisms of drug action and resistance. Until now, the real-time determination of the redox potential in malaria parasites has been limited because conventional approaches disrupt sub-cellular integrity. Using a glutathione biosensor comprising human glutaredoxin-1 linked to a redox-sensitive green fluorescent protein (hGrx1-roGFP2), we systematically characterized basal values and drug-induced changes in the cytosolic glutathione-dependent redox potential (EGSH) of drug-sensitive (3D7) and resistant (Dd2) P. falciparum parasites. Via confocal microscopy, we demonstrated that hGrx1-roGFP2 rapidly detects EGSH changes induced by oxidative and nitrosative stress. The cytosolic basal EGSH of 3D7 and Dd2 were estimated to be −314.2±3.1 mV and −313.9±3.4 mV, respectively, which is indicative of a highly reducing compartment. We furthermore monitored short-, medium-, and long-term changes in EGSH after incubation with various redox-active compounds and antimalarial drugs. Interestingly, the redox cyclers methylene blue and pyocyanin rapidly changed the fluorescence ratio of hGrx1-roGFP2 in the cytosol of P. falciparum, which can, however, partially be explained by a direct interaction with the probe. In contrast, quinoline and artemisinin-based antimalarial drugs showed strong effects on the parasites' EGSH after longer incubation times (24 h). As tested for various conditions, these effects were accompanied by a drop in total glutathione concentrations determined in parallel with alternative methods. Notably, the effects were generally more pronounced in the chloroquine-sensitive 3D7 strain than in the resistant Dd2 strain. Based on these results hGrx1-roGFP2 can be recommended as a reliable and specific biosensor for real-time spatiotemporal monitoring of the intracellular EGSH in P. falciparum. Applying this technique in further

  7. Efficacy and effectiveness of mefloquine and artesunate combination therapy for uncomplicated Plasmodium falciparum malaria in the Peruvian Amazon.

    PubMed

    de Oliveira, Alexandre Macedo; Chavez, Jorge; de Leon, Gabriel Ponce; Durand, Salomon; Arrospide, Nancy; Roberts, Jacquelin; Cabezas, Cesar; Marquiño, Wilmer

    2011-09-01

    We evaluated the efficacy and effectiveness of mefloquine (MQ) plus artesunate (AS) to treat patients with uncomplicated malaria in the Peruvian Amazon Basin in April 2005-March 2006. Patients ≥ 1 year of age with fever (axillary temperature ≥ 37.5°C) or history of fever and Plasmodium falciparum monoinfection were included. Patients received antimalarial treatment with MQ (12.5 mg/kg/day for two days) and AS (4.0 mg/kg/day for three days) either by directly observed therapy or without directly observed therapy. After a 28-day follow-up, treatment efficacy and effectiveness were assessed on the basis of clinical and parasitologic outcomes. Ninety-six patients were enrolled in each study group; nine patients were lost to follow-up. All patients, except for one in the observed group, demonstrated adequate clinical and parasitologic response; none had detectable parasitemia on day 3. The efficacy of MQ + AS efficacy was 98.9% (95% confidence interval = 94.1-100.0%) and the effectiveness was 100.0% (95% confidence interval = 95.9-100.0%). Our study shows that MQ + AS is highly efficacious in the Peruvian Amazon.

  8. Plasmodium vivax and Plasmodium falciparum at the Crossroads of Exchange among Islands in Vanuatu: Implications for Malaria Elimination Strategies

    PubMed Central

    Chan, Chim W.; Sakihama, Naoko; Tachibana, Shin-Ichiro; Idris, Zulkarnain Md; Lum, J. Koji; Kaneko, Akira

    2015-01-01

    Understanding the transmission and movement of Plasmodium parasites is crucial for malaria elimination and prevention of resurgence. Located at the limit of malaria transmission in the Pacific, Vanuatu is an ideal candidate for elimination programs due to low endemicity and the isolated nature of its island setting. We analyzed the variation in the merozoite surface protein 1 (msp1) and the circumsporozoite protein (csp) of P. falciparum and P. vivax populations to examine the patterns of gene flow and population structures among seven sites on five islands in Vanuatu. Genetic diversity was in general higher in P. vivax than P. falciparum from the same site. In P. vivax, high genetic diversity was likely maintained by greater extent of gene flow among sites and among islands. Consistent with the different patterns of gene flow, the proportion of genetic variance found among islands was substantially higher in P. falciparum (28.81–31.23%) than in P. vivax (-0.53–3.99%). Our data suggest that the current island-by-island malaria elimination strategy in Vanuatu, while adequate for P. falciparum elimination, might need to be complemented with more centrally integrated measures to control P. vivax movement across islands. PMID:25793260

  9. An Imported Case of Severe Falciparum Malaria with Prolonged Hemolytic Anemia Clinically Mimicking a Coinfection with Babesiosis

    PubMed Central

    Na, Young Ju; Chai, Jong-Yil; Jung, Bong-Kwang; Lee, Hyun Jung; Song, Ji Young; Je, Ji Hye; Seo, Ji Hye; Park, Sung Hun; Choi, Ji Seon

    2014-01-01

    While imported falciparum malaria has been increasingly reported in recent years in Korea, clinicians have difficulties in making a clinical diagnosis as well as in having accessibility to effective anti-malarial agents. Here we describe an unusual case of imported falciparum malaria with severe hemolytic anemia lasting over 2 weeks, clinically mimicking a coinfection with babesiosis. A 48-year old Korean man was diagnosed with severe falciparum malaria in France after traveling to the Republic of Benin, West Africa. He received a 1-day course of intravenous artesunate and a 7-day course of Malarone (atovaquone/proguanil) with supportive hemodialysis. Coming back to Korea 5 days after discharge, he was readmitted due to recurrent fever, and further treated with Malarone for 3 days. Both the peripheral blood smears and PCR test were positive for Plasmodium falciparum. However, he had prolonged severe hemolytic anemia (Hb 5.6 g/dl). Therefore, 10 days after the hospitalization, Babesia was considered to be potentially coinfected. A 7-day course of Malarone and azithromycin was empirically started. He became afebrile within 3 days of this babesiosis treatment, and hemolytic anemia profiles began to improve at the completion of the treatment. He has remained stable since his discharge. Unexpectedly, the PCR assays failed to detect DNA of Babesia spp. from blood. In addition, during the retrospective review of the case, the artesunate-induced delayed hemolytic anemia was considered as an alternative cause of the unexplained hemolytic anemia. PMID:25548419

  10. Plasmodium falciparum Genotype Diversity in Artemisinin Derivatives Treatment Failure Patients along the Thai-Myanmar Border

    PubMed Central

    Hoonchaiyapoom, Thirasak; Inorn, Kornnarin

    2014-01-01

    Genetic characteristics of Plasmodium falciparum may play a role in the treatment outcome of malaria infection. We have studied the association between diversity at the merozoite surface protein-1 (msp-1), msp-2, and glutamate-rich protein (glurp) loci and the treatment outcome of uncomplicated falciparum malaria patients along the Thai-Myanmar border who were treated with artemisinin derivatives combination therapy. P. falciparum isolates were collected prior to treatment from 3 groups of patients; 50 cases of treatment failures, 50 recrudescences, and 56 successful treatments. Genotyping of the 3 polymorphic markers was analyzed by nested PCR. The distribution of msp-1 alleles was significantly different among the 3 groups of patients but not the msp-2 and glurp alleles. The allelic frequencies of K1 and MAD20 alleles of msp1 gene were higher while RO33 allele was significantly lower in the successful treatment group. Treatment failure samples had a higher median number of alleles as compared to the successful treatment group. Specific genotypes of msp-1, msp-2, and glurp were significantly associated with the treatment outcomes. Three allelic size variants were significantly higher among the isolates from the treatment failure groups, i.e., K1270-290, 3D7610-630, G650-690, while 2 variants, K1150-170, and 3D7670-690 were significantly lower. In conclusion, the present study reports the differences in multiplicity of infection and distribution of specific alleles of msp-1, msp-2, and glurp genes in P. falciparum isolates obtained from treatment failure and successful treatment patients following artemisinin derivatives combination therapy. PMID:25548414

  11. Prevalence of Plasmodium falciparum transmission reducing immunity among primary school children in a malaria moderate transmission region in Zimbabwe.

    PubMed

    Paul, Noah H; Vengesai, Arthur; Mduluza, Takafira; Chipeta, James; Midzi, Nicholas; Bansal, Geetha P; Kumar, Nirbhay

    2016-11-01

    Malaria continues to cause alarming morbidity and mortality in more than 100 countries worldwide. Antigens in the various life cycle stages of malaria parasites are presented to the immune system during natural infection and it is widely recognized that after repeated malaria exposure, adults develop partially protective immunity. Specific antigens of natural immunity represent among the most important targets for the development of malaria vaccines. Immunity against the transmission stages of the malaria parasite represents an important approach to reduce malaria transmission and is believed to become an important tool for gradual elimination of malaria. Development of immunity against Plasmodium falciparum sexual stages was evaluated in primary school children aged 6-16 years in Makoni district of Zimbabwe, an area of low to modest malaria transmission. Malaria infection was screened by microscopy, rapid diagnostic tests and finally using nested PCR. Plasma samples were tested for antibodies against recombinant Pfs48/45 and Pfs47 by ELISA. Corresponding serum samples were used to test for P. falciparum transmission reducing activity in Anopheles stephensi and An. gambiae mosquitoes using the membrane feeding assay. The prevalence of malaria diagnosed by rapid diagnostic test kit (Paracheck)™ was 1.7%. However, of the randomly tested blood samples, 66% were positive by nested PCR. ELISA revealed prevalence (64% positivity at 1:500 dilution, in randomly selected 66 plasma samples) of antibodies against recombinant Pfs48/45 (mean A 405nm=0.53, CI=0.46-0.60) and Pfs47 (mean A405nm=0.91, CI=0.80-1.02); antigens specific to the sexual stages. The mosquito membrane feeding assay demonstrated measurable transmission reducing ability of the samples that were positive for Pfs48/45 antibodies by ELISA. Interestingly, 3 plasma samples revealed enhancement of infectivity of P. falciparum in An. stephensi mosquitoes. These studies revealed the presence of antibodies with

  12. Malaria vaccine candidate antigen targeting the pre-erythrocytic stage of Plasmodium falciparum produced at high level in plants.

    PubMed

    Voepel, Nadja; Boes, Alexander; Edgue, Güven; Beiss, Veronique; Kapelski, Stephanie; Reimann, Andreas; Schillberg, Stefan; Pradel, Gabriele; Fendel, Rolf; Scheuermayer, Matthias; Spiegel, Holger; Fischer, Rainer

    2014-11-01

    Plants have emerged as low-cost production platforms suitable for vaccines targeting poverty-related diseases. Besides functional efficacy, the stability, yield, and purification process determine the production costs of a vaccine and thereby the feasibility of plant-based production. We describe high-level plant production and functional characterization of a malaria vaccine candidate targeting the pre-erythrocytic stage of Plasmodium falciparum. CCT, a fusion protein composed of three sporozoite antigens (P. falciparum cell traversal protein for ookinetes and sporozoites [PfCelTOS], P. falciparum circumsporozoite protein [PfCSP], and P. falciparum thrombospondin-related adhesive protein [PfTRAP]), was transiently expressed by agroinfiltration in Nicotiana benthamiana leaves, accumulated to levels up to 2 mg/g fresh leaf weight (FLW), was thermostable up to 80°C and could be purified to >95% using a simple two-step procedure. Reactivity of sera from malaria semi-immune donors indicated the immunogenic conformation of the purified fusion protein consisting of PfCelTOS, PfCSP_TSR, PfTRAP_TSR domains (CCT) protein. Total IgG from the CCT-specific mouse immune sera specifically recognized P. falciparum sporozoites in immunofluorescence assays and induced up to 35% inhibition in hepatocyte invasion assays. Featuring domains from three promising sporozoite antigens with different roles (attachment and cell traversal) in the hepatocyte invasion process, CCT has the potential to elicit broader immune responses against the pre-erythrocytic stage of P. falciparum and represents an interesting new candidate, also as a component of multi-stage, multi-subunit malaria vaccine cocktails. PMID:25200253

  13. Genetic variability and population structure of Plasmodium falciparum parasite populations from different malaria ecological regions of Kenya.

    PubMed

    Ingasia, Luicer A; Cheruiyot, Jelagat; Okoth, Sheila Akinyi; Andagalu, Ben; Kamau, Edwin

    2016-04-01

    Transmission intensity, movement of human and vector hosts, biogeographical features, and malaria control measures are some of the important factors that determine Plasmodium falciparum parasite genetic variability and population structure. Kenya has different malaria ecologies which might require different disease intervention methods. Refined parasite population genetic studies are critical for informing malaria control and elimination strategies. This study describes the genetic diversity and population structure of P. falciparum parasites from the different malaria ecological zones in Kenya. Twelve multi-locus microsatellite (MS) loci previously described were genotyped in 225 P. falciparum isolates collected between 2012 and 2013 from five sites; three in lowland endemic regions (Kisumu, Kombewa, and Malindi) and two in highland, epidemic regions (Kisii and Kericho). Parasites from the lowland endemic and highland epidemic regions of western Kenya had high genetic diversity compared to coastal lowland endemic region of Kenya [Malindi]. The Kenyan parasites had a mean genetic differentiation index (FST) of 0.072 (p=0.011). The multi-locus genetic analysis of the 12 MS revealed all the parasites had unique haplotypes. Significant linkage disequilibrium (LD) was observed in all the five parasite populations. Kisumu had the most significant index of association values (0.16; p<0.0001) whereas Kisii had the least significant index of association values (0.03; p<0.0001). Our data suggest high genetic diversity in Kenyan parasite population with the exception of parasite from Malindi where malaria has been on the decline. The presence of significant LD suggests that there is occurrence of inbreeding in the parasite population. Parasite populations from Kisii showed the strongest evidence for epidemic population structure whereas the rest of the regions showed panmixia. Defining the genetic diversity of the parasites in different ecological regions of Kenya after

  14. Reduced Parasite Burden in Children with Falciparum Malaria and Bacteremia Coinfections: Role of Mediators of Inflammation

    DOE PAGES

    Davenport, Gregory C.; Hittner, James B.; Otieno, Vincent; Karim, Zachary; Mukundan, Harshini; Fenimore, Paul W.; Hengartner, Nicolas W.; McMahon, Benjamin H.; Kempaiah, Prakasha; Ong’echa, John M.; et al

    2016-01-01

    Bmore » acteremia and malaria coinfection is a common and life-threatening condition in children residing in sub-Saharan Africa. We previously showed that coinfection with Gram negative (G[−]) entericacilli and Plasmodium falciparum ( Pf [+]) was associated with reduced high-density parasitemia (HDP, >10,000 parasites/ μ L), enhanced respiratory distress, and severe anemia. Since inflammatory mediators are largely unexplored in such coinfections, circulating cytokines were determined in four groups of children ( n = 206 , aged <3 yrs): healthy; Pf [+] alone; G[−] coinfected; and G[+] coinfected. Staphylococcus aureus and non-Typhi Salmonella were the most frequently isolated G[+] and G[−] organisms, respectively. Coinfected children, particularly those with G[−] pathogens, had lower parasite burden (peripheral and geometric mean parasitemia and HDP). In addition, both coinfected groups had increased IL-4, IL-5, IL-7, IL-12, IL-15, IL-17, IFN- γ , and IFN- α and decreased TNF- α relative to malaria alone. Children with G[−] coinfection had higher IL-1 β and IL-1Ra and lower IL-10 than the Pf [+] group and higher IFN- γ than the G[+] group. To determine how the immune response to malaria regulates parasitemia, cytokine production was investigated with a multiple mediation model. Cytokines with the greatest mediational impact on parasitemia were IL-4, IL-10, IL-12, and IFN- γ . Results here suggest that enhanced immune activation, especially in G[−] coinfected children, acts to reduce malaria parasite burden.« less

  15. Reduced Parasite Burden in Children with Falciparum Malaria and Bacteremia Coinfections: Role of Mediators of Inflammation

    PubMed Central

    Davenport, Gregory C.; Mukundan, Harshini; Fenimore, Paul W.; Hengartner, Nicolas W.; McMahon, Benjamin H.; Ong'echa, John M.

    2016-01-01

    Bacteremia and malaria coinfection is a common and life-threatening condition in children residing in sub-Saharan Africa. We previously showed that coinfection with Gram negative (G[−]) enteric Bacilli and Plasmodium falciparum (Pf[+]) was associated with reduced high-density parasitemia (HDP, >10,000 parasites/μL), enhanced respiratory distress, and severe anemia. Since inflammatory mediators are largely unexplored in such coinfections, circulating cytokines were determined in four groups of children (n = 206, aged <3 yrs): healthy; Pf[+] alone; G[−] coinfected; and G[+] coinfected. Staphylococcus aureus and non-Typhi Salmonella were the most frequently isolated G[+] and G[−] organisms, respectively. Coinfected children, particularly those with G[−] pathogens, had lower parasite burden (peripheral and geometric mean parasitemia and HDP). In addition, both coinfected groups had increased IL-4, IL-5, IL-7, IL-12, IL-15, IL-17, IFN-γ, and IFN-α and decreased TNF-α relative to malaria alone. Children with G[−] coinfection had higher IL-1β and IL-1Ra and lower IL-10 than the Pf[+] group and higher IFN-γ than the G[+] group. To determine how the immune response to malaria regulates parasitemia, cytokine production was investigated with a multiple mediation model. Cytokines with the greatest mediational impact on parasitemia were IL-4, IL-10, IL-12, and IFN-γ. Results here suggest that enhanced immune activation, especially in G[−] coinfected children, acts to reduce malaria parasite burden. PMID:27418744

  16. PfEMP1 - A Parasite Protein Family of Key Importance in Plasmodium falciparum Malaria Immunity and Pathogenesis.

    PubMed

    Hviid, Lars; Jensen, Anja T R

    2015-04-01

    Plasmodium falciparum causes the most severe form of malaria and is responsible for essentially all malaria-related deaths. The accumulation in various tissues of erythrocytes infected by mature P. falciparum parasites can lead to circulatory disturbances and inflammation, and is thought to be a central element in the pathogenesis of the disease. It is mediated by the interaction of parasite ligands on the erythrocyte surface and a range of host receptor molecules in many organs and tissues. Among several proteins and protein families implicated in this process, the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family of high-molecular weight and highly variable antigens appears to be the most prominent. In this chapter, we aim to provide a systematic overview of the current knowledge about these proteins, their structure, their function, how they are presented on the erythrocyte surface, and how the var genes encoding them are regulated. The role of PfEMP1 in the pathogenesis of malaria, PfEMP1-specific immune responses, and the prospect of PfEMP1-specific vaccination against malaria are also covered briefly.

  17. Water and urea transport in human erythrocytes infected with the malaria parasite Plasmodium falciparum.

    PubMed

    Zanner, M A; Galey, W R; Scaletti, J V; Brahm, J; Vander Jagt, D L

    1990-05-01

    The permeability properties of the human red cell membrane to various solutes are altered by malarial infection. In the present work we show that the permeability of the red cell membrane to water is also affected by the intraerythrocytic growth of the malaria parasite Plasmodium falciparum, whereas urea permeability appears unchanged. The data from infected cells show decreases in membrane surface area, cell volume, the osmotically active water fraction (Weff), and osmotic water permeability (Pf) as measured by stopped-flow spectroscopy. On the other hand, the data suggest an increase in diffusive water permeability (Pd) in infected cells with no change in urea permeability when measured by the continuous flow method. The decreased Pf/Pd ratio of infected cell membranes and its implications in the geometry of the red cell membrane water channel or pore are discussed. PMID:2194124

  18. Human Monoclonal Antibodies to Pf 155, a Major Antigen of Malaria Parasite Plasmodium falciparum

    NASA Astrophysics Data System (ADS)

    Udomsangpetch, Rachanee; Lundgren, Katarina; Berzins, Klavs; Wahlin, Birgitta; Perlmann, Hedvig; Troye-Blomberg, Marita; Carlsson, Jan; Wahlgren, Mats; Perlmann, Peter; Bjorkman, Anders

    1986-01-01

    Pf 155, a protein of the human malaria parasite Plasmodium falciparum, is strongly immunogenic in humans and is believed to be a prime candidate for the preparation of a vaccine. Human monoclonal antibodies to Pf 155 were obtained by cloning B cells that had been prepared from an immune donor and transformed with Epstein-Barr virus. When examined by indirect immunofluorescence, these antibodies stained the surface of infected erythrocytes, free merozoites, segmented schizonts, and gametocytes. They bound to a major polypeptide with a relative molecular weight of 155K and to two minor ones (135K and 120K), all having high affinity for human glycophorin. The antibodies strongly inhibited merozoite reinvasion in vitro, suggesting that they might be appropriate reagents for therapeutic administration in vivo.

  19. Plasmodium falciparum STEVOR phosphorylation regulates host erythrocyte deformability enabling malaria parasite transmission.

    PubMed

    Naissant, Bernina; Dupuy, Florian; Duffier, Yoann; Lorthiois, Audrey; Duez, Julien; Scholz, Judith; Buffet, Pierre; Merckx, Anais; Bachmann, Anna; Lavazec, Catherine

    2016-06-16

    Deformability of Plasmodium falciparum gametocyte-infected erythrocytes (GIEs) allows them to persist for several days in blood circulation and to ensure transmission to mosquitoes. Here, we investigate the mechanism by which the parasite proteins STEVOR (SubTElomeric Variable Open Reading frame) exert changes on GIE deformability. Using the microsphiltration method, immunoprecipitation, and mass spectrometry, we produce evidence that GIE stiffness is dependent on the cytoplasmic domain of STEVOR that interacts with ankyrin complex at the erythrocyte skeleton. Moreover, we show that GIE deformability is regulated by protein kinase A (PKA)-mediated phosphorylation of the STEVOR C-terminal domain at a specific serine residue (S324). Finally, we show that the increase of GIE stiffness induced by sildenafil (Viagra) is dependent on STEVOR phosphorylation status and on another independent mechanism. These data provide new insights into mechanisms by which phosphodiesterase inhibitors may block malaria parasite transmission. PMID:27136945

  20. Plasmodium falciparum STEVOR phosphorylation regulates host erythrocyte deformability enabling malaria parasite transmission.

    PubMed

    Naissant, Bernina; Dupuy, Florian; Duffier, Yoann; Lorthiois, Audrey; Duez, Julien; Scholz, Judith; Buffet, Pierre; Merckx, Anais; Bachmann, Anna; Lavazec, Catherine

    2016-06-16

    Deformability of Plasmodium falciparum gametocyte-infected erythrocytes (GIEs) allows them to persist for several days in blood circulation and to ensure transmission to mosquitoes. Here, we investigate the mechanism by which the parasite proteins STEVOR (SubTElomeric Variable Open Reading frame) exert changes on GIE deformability. Using the microsphiltration method, immunoprecipitation, and mass spectrometry, we produce evidence that GIE stiffness is dependent on the cytoplasmic domain of STEVOR that interacts with ankyrin complex at the erythrocyte skeleton. Moreover, we show that GIE deformability is regulated by protein kinase A (PKA)-mediated phosphorylation of the STEVOR C-terminal domain at a specific serine residue (S324). Finally, we show that the increase of GIE stiffness induced by sildenafil (Viagra) is dependent on STEVOR phosphorylation status and on another independent mechanism. These data provide new insights into mechanisms by which phosphodiesterase inhibitors may block malaria parasite transmission.

  1. Artesunate versus quinine in the treatment of severe falciparum malaria in African children (AQUAMAT): an open-label, randomised trial

    PubMed Central

    Dondorp, Arjen M; Fanello, Caterina I; Hendriksen, Ilse CE; Gomes, Ermelinda; Seni, Amir; Chhaganlal, Kajal D; Bojang, Kalifa; Olaosebikan, Rasaq; Anunobi, Nkechinyere; Maitland, Kathryn; Kivaya, Esther; Agbenyega, Tsiri; Nguah, Samuel Blay; Evans, Jennifer; Gesase, Samwel; Kahabuka, Catherine; Mtove, George; Nadjm, Behzad; Deen, Jacqueline; Mwanga-Amumpaire, Juliet; Nansumba, Margaret; Karema, Corine; Umulisa, Noella; Uwimana, Aline; Mokuolu, Olugbenga A; Adedoyin, Olanrewaju T; Johnson, Wahab BR; Tshefu, Antoinette K; Onyamboko, Marie A; Sakulthaew, Tharisara; Ngum, Wirichada Pan; Silamut, Kamolrat; Stepniewska, Kasia; Woodrow, Charles J; Bethell, Delia; Wills, Bridget; Oneko, Martina; Peto, Tim E; von Seidlein, Lorenz; Day, Nicholas PJ; White, Nicholas J

    2010-01-01

    Summary Background Severe malaria is a major cause of childhood death and often the main reason for paediatric hospital admission in sub-Saharan Africa. Quinine is still the established treatment of choice, although evidence from Asia suggests that artesunate is associated with a lower mortality. We compared parenteral treatment with either artesunate or quinine in African children with severe malaria. Methods This open-label, randomised trial was undertaken in 11 centres in nine African countries. Children (<15 years) with severe falciparum malaria were randomly assigned to parenteral artesunate or parenteral quinine. Randomisation was in blocks of 20, with study numbers corresponding to treatment allocations kept inside opaque sealed paper envelopes. The trial was open label at each site, and none of the investigators or trialists, apart from for the trial statistician, had access to the summaries of treatment allocations. The primary outcome measure was in-hospital mortality, analysed by intention to treat. This trial is registered, number ISRCTN50258054. Findings 5425 children were enrolled; 2712 were assigned to artesunate and 2713 to quinine. All patients were analysed for the primary outcome. 230 (8·5%) patients assigned to artesunate treatment died compared with 297 (10·9%) assigned to quinine treatment (odds ratio [OR] stratified for study site 0·75, 95% CI 0·63–0·90; relative reduction 22·5%, 95% CI 8·1–36·9; p=0·0022). Incidence of neurological sequelae did not differ significantly between groups, but the development of coma (65/1832 [3·5%] with artesunate vs 91/1768 [5·1%] with quinine; OR 0·69 95% CI 0·49–0·95; p=0·0231), convulsions (224/2712 [8·3%] vs 273/2713 [10·1%]; OR 0·80, 0·66–0·97; p=0·0199), and deterioration of the coma score (166/2712 [6·1%] vs 208/2713 [7·7%]; OR 0·78, 0·64–0·97; p=0·0245) were all significantly less frequent in artesunate recipients than in quinine recipients. Post

  2. Efficacy and tolerability of artesunate plus sulfadoxine-pyrimethamine and sulfadoxine-pyrimethamine alone for the treatment of uncomplicated Plasmodium falciparum malaria in Peru.

    PubMed

    Marquiño, Wilmer; Ylquimiche, Laura; Hermenegildo, Ygor; Palacios, Ana Maria; Falconí, Eduardo; Cabezas, César; Arróspide, Nancy; Gutierrez, Sonia; Ruebush, Trenton K

    2005-05-01

    To assist the Peruvian Ministry of Health in modifying the malaria treatment policy for their north Pacific coastal region, we conducted an in vivo efficacy trial of sulfadoxine-pyrimethamine (SP) and SP plus artesunate (SP-AS) for the treatment for uncomplicated Plasmodium falciparum infections. A total of 197 patients were randomized to therapy with either SP (25 mg/kg of the sulfadoxine component in a single dose on day 0) or a combination of SP plus AS (4 mg/kg on days 0, 1, and 2) and were followed for 28 days for symptoms and recurrence of parasitemia. No statistically significant differences between the two groups were observed on enrollment with respect to age, sex, history of malaria, or geometric mean parasite density. A total of 185 subjects completed the 28-day follow-up. Of the 91 subjects treated with SP alone, two had recurrences of parasitemia on day 7 and one on day 21. Of the 94 subjects treated with SP-AS, one had a recurrence of parasitemia on day 21. Fever and asexual parasite density decreased significantly more rapidly and the proportion of patients with gametocytemia on days 3-28 was significantly lower in subjects treated with combination therapy than in those who received SP alone. No severe adverse drug reactions were observed; however, self-limited rash and pruritus were significantly more common and an exacerbation of nausea, vomiting, and abdominal pain were observed significantly more frequently among patients who had received SP-AS. These results have contributed to a National Malaria Control Program decision to change to SP-AS combination therapy as the first-line treatment for uncomplicated P. falciparum malaria in northern coastal Peru in November 2001, making Peru the first country in the Americas to recommend this combination therapy.

  3. Protein Export Marks the Early Phase of Gametocytogenesis of the Human Malaria Parasite Plasmodium falciparum*

    PubMed Central

    Silvestrini, Francesco; Lasonder, Edwin; Olivieri, Anna; Camarda, Grazia; van Schaijk, Ben; Sanchez, Massimo; Younis Younis, Sumera; Sauerwein, Robert; Alano, Pietro

    2010-01-01

    Despite over a century of study of malaria parasites, parts of the Plasmodium falciparum life cycle remain virtually unknown. One of these is the early gametocyte stage, a round shaped cell morphologically similar to an asexual trophozoite in which major cellular transformations ensure subsequent development of the elongated gametocyte. We developed a protocol to obtain for the first time highly purified preparations of early gametocytes using a transgenic line expressing a green fluorescent protein from the onset of gametocytogenesis. We determined the cellular proteome (1427 proteins) of this parasite stage by high accuracy tandem mass spectrometry and newly determined the proteomes of asexual trophozoites and mature gametocytes, identifying altogether 1090 previously undetected parasite proteins. Quantitative label-free comparative proteomics analysis determined enriched protein clusters for the three parasite developmental stages. Gene set enrichment analysis on the 251 proteins enriched in the early gametocyte proteome revealed that proteins putatively exported and involved in erythrocyte remodeling are the most overrepresented protein set in these stages. One-tenth of the early gametocyte-enriched proteome is constituted of putatively exported proteins, here named PfGEXPs (P. falciparum gametocyte-exported proteins). N-terminal processing and N-acetylation at a conserved leucine residue within the Plasmodium export element pentamotif were detected by mass spectrometry for three such proteins in the early but not in the mature gametocyte sample, further supporting a specific role in protein export in early gametocytogenesis. Previous reports and results of our experiments confirm that the three proteins are indeed exported in the erythrocyte cytoplasm. This work indicates that protein export profoundly marks early sexual differentiation in P. falciparum, probably contributing to host cell remodeling in this phase of the life cycle, and that gametocyte

  4. Direct Tests of Enzymatic Heme Degradation by the Malaria Parasite Plasmodium falciparum*

    PubMed Central

    Sigala, Paul A.; Crowley, Jan R.; Hsieh, Samantha; Henderson, Jeffrey P.; Goldberg, Daniel E.

    2012-01-01

    Malaria parasites generate vast quantities of heme during blood stage infection via hemoglobin digestion and limited de novo biosynthesis, but it remains unclear if parasites metabolize heme for utilization or disposal. Recent in vitro experiments with a heme oxygenase (HO)-like protein from Plasmodium falciparum suggested that parasites may enzymatically degrade some heme to the canonical HO product, biliverdin (BV), or its downstream metabolite, bilirubin (BR). To directly test for BV and BR production by P. falciparum parasites, we DMSO-extracted equal numbers of infected and uninfected erythrocytes and developed a sensitive LC-MS/MS assay to quantify these tetrapyrroles. We found comparable low levels of BV and BR in both samples, suggesting the absence of HO activity in parasites. We further tested live parasites by targeted expression of a fluorescent BV-binding protein within the parasite cytosol, mitochondrion, and plant-like plastid. This probe could detect exogenously added BV but gave no signal indicative of endogenous BV production within parasites. Finally, we recombinantly expressed and tested the proposed heme degrading activity of the HO-like protein, PfHO. Although PfHO bound heme and protoporphyrin IX with modest affinity, it did not catalyze heme degradation in vivo within bacteria or in vitro in UV absorbance and HPLC assays. These observations are consistent with PfHO's lack of a heme-coordinating His residue and suggest an alternative function within parasites. We conclude that P. falciparum parasites lack a canonical HO pathway for heme degradation and thus rely fully on alternative mechanisms for heme detoxification and iron acquisition during blood stage infection. PMID:22992734

  5. Erythrocyte sequestration and anemia in severe falciparum malaria. Analysis of acute changes in venous hematocrit using a simple mathematical model.

    PubMed Central

    Davis, T M; Krishna, S; Looareesuwan, S; Supanaranond, W; Pukrittayakamee, S; Attatamsoonthorn, K; White, N J

    1990-01-01

    Microvascular erythrocyte sequestration, the characteristic pathological feature of falciparum malaria, was evaluated using a mathematical model in 46 patients with severe infections. From admission radioisotopic circulating red cell volumes and simultaneous venous hematocrits, the model-derived sequestrum hematocrit (mean [95% confidence limits]: 0.70 [0.43-0.97], n = 29) was twice that of peripheral blood (0.33 [0.30-0.36]). Serial reticulocyte and radiolabeled erythrocyte counts indicated that small numbers of cells enter the circulation during initial therapy. The mean fall in hematocrit over 84 h in 26 nontransfused patients conformed to a three-term equation. A first-order decline (t1/2 2.0 h [0.6-3.4]) suggested an average 7.5% plasma volume expansion through rehydration. A zero-order 6.3% (3.1-9.5) fall (t1/2 25.7 h [21.2-30.2]) occurred contemporaneously with a fall in mean parasitemia from 4.5% (3.6-5.4); from these data the model-derived average sequestered erythrocyte volume (4.8% of the admission hematocrit) was similar to the peripheral parasite burden. A second, first-order fall (t1/2 1,047 h [278-1,816]) indicated loss of uninfected erythrocytes with mean lifespan 62 d. Predicted total plasma volume expansion during initial therapy (21.2%) was similar to radioisotopic estimates in 11 patients (17.3% [2.0-33.1]). Application of the model to individual patient data showed wide variations in relative proportions of circulating and sequestered parasitized cells. The model provides evidence of the nature and fate of all parasitized erythrocytes in malaria. PMID:2203822

  6. Nanovaccines for malaria using Plasmodium falciparum antigen Pfs25 attached gold nanoparticles.

    PubMed

    Kumar, Rajesh; Ray, Paresh C; Datta, Dibyadyuti; Bansal, Geetha P; Angov, Evelina; Kumar, Nirbhay

    2015-09-22

    Malaria transmission-blocking vaccines (TBV) targeting sexual stages of the parasite represent an ideal intervention to reduce the burden of the disease and eventual elimination at the population level in endemic regions. Immune responses against sexual stage antigens impair the development of parasite inside the mosquitoes. Target antigens identified in Plasmodium falciparum include surface proteins Pfs230 and Pfs48/45 in male and female gametocytes and Pfs25 expressed in zygotes and ookinetes. The latter has undergone extensive evaluation in pre-clinical and phase I clinical trials and remains one of the leading target antigens for the development of TBV. Pfs25 has a complex tertiary structure characterized by four EGF-like repeat motifs formed by 11 disulfide bonds, and it has been rather difficult to obtain Pfs25 as a homogenous product in native conformation in any heterologous expression system. Recently, we have reported expression of codon-harmonized recombinant Pfs25 in Escherichia coli (CHrPfs25) and which elicited highly potent malaria transmission-blocking antibodies in mice. In the current study, we investigated CHrPfs25 along with gold nanoparticles of different shapes, size and physicochemical properties as adjuvants for induction of transmission blocking immunity. The results revealed that CHrPfs25 delivered with various gold nanoparticles elicited strong transmission blocking antibodies and suggested that gold nanoparticles based formulations can be developed as nanovaccines to enhance the immunogenicity of vaccine antigens.

  7. Defining the relationship between infection prevalence and clinical incidence of Plasmodium falciparum malaria

    PubMed Central

    Cameron, Ewan; Battle, Katherine E.; Bhatt, Samir; Weiss, Daniel J.; Bisanzio, Donal; Mappin, Bonnie; Dalrymple, Ursula; Hay, Simon I.; Smith, David L.; Griffin, Jamie T.; Wenger, Edward A.; Eckhoff, Philip A.; Smith, Thomas A.; Penny, Melissa A.; Gething, Peter W.

    2015-01-01

    In many countries health system data remain too weak to accurately enumerate Plasmodium falciparum malaria cases. In response, cartographic approaches have been developed that link maps of infection prevalence with mathematical relationships to predict the incidence rate of clinical malaria. Microsimulation (or ‘agent-based') models represent a powerful new paradigm for defining such relationships; however, differences in model structure and calibration data mean that no consensus yet exists on the optimal form for use in disease-burden estimation. Here we develop a Bayesian statistical procedure combining functional regression-based model emulation with Markov Chain Monte Carlo sampling to calibrate three selected microsimulation models against a purpose-built data set of age-structured prevalence and incidence counts. This allows the generation of ensemble forecasts of the prevalence–incidence relationship stratified by age, transmission seasonality, treatment level and exposure history, from which we predict accelerating returns on investments in large-scale intervention campaigns as transmission and prevalence are progressively reduced. PMID:26348689

  8. Controlled Human Malaria Infection of Tanzanians by Intradermal Injection of Aseptic, Purified, Cryopreserved Plasmodium falciparum Sporozoites

    PubMed Central

    Shekalaghe, Seif; Rutaihwa, Mastidia; Billingsley, Peter F.; Chemba, Mwajuma; Daubenberger, Claudia A.; James, Eric R.; Mpina, Maximillian; Ali Juma, Omar; Schindler, Tobias; Huber, Eric; Gunasekera, Anusha; Manoj, Anita; Simon, Beatus; Saverino, Elizabeth; Church, L. W. Preston; Hermsen, Cornelus C.; Sauerwein, Robert W.; Plowe, Christopher; Venkatesan, Meera; Sasi, Philip; Lweno, Omar; Mutani, Paul; Hamad, Ali; Mohammed, Ali; Urassa, Alwisa; Mzee, Tutu; Padilla, Debbie; Ruben, Adam; Lee Sim, B. Kim; Tanner, Marcel; Abdulla, Salim; Hoffman, Stephen L.

    2014-01-01

    Controlled human malaria infection (CHMI) by mosquito bite has been used to assess anti-malaria interventions in > 1,500 volunteers since development of methods for infecting mosquitoes by feeding on Plasmodium falciparum (Pf) gametocyte cultures. Such CHMIs have never been used in Africa. Aseptic, purified, cryopreserved Pf sporozoites, PfSPZ Challenge, were used to infect Dutch volunteers by intradermal injection. We conducted a double-blind, placebo-controlled trial to assess safety and infectivity of PfSPZ Challenge in adult male Tanzanians. Volunteers were injected intradermally with 10,000 (N = 12) or 25,000 (N = 12) PfSPZ or normal saline (N = 6). PfSPZ Challenge was well tolerated and safe. Eleven of 12 and 10 of 11 subjects, who received 10,000 and 25,000 PfSPZ respectively, developed parasitemia. In 10,000 versus 25,000 PfSPZ groups geometric mean days from injection to Pf positivity by thick blood film was 15.4 versus 13.5 (P = 0.023). Alpha-thalassemia heterozygosity had no apparent effect on infectivity. PfSPZ Challenge was safe, well tolerated, and infectious. PMID:25070995

  9. Defining the relationship between infection prevalence and clinical incidence of Plasmodium falciparum malaria.

    PubMed

    Cameron, Ewan; Battle, Katherine E; Bhatt, Samir; Weiss, Daniel J; Bisanzio, Donal; Mappin, Bonnie; Dalrymple, Ursula; Hay, Simon I; Smith, David L; Griffin, Jamie T; Wenger, Edward A; Eckhoff, Philip A; Smith, Thomas A; Penny, Melissa A; Gething, Peter W

    2015-01-01

    In many countries health system data remain too weak to accurately enumerate Plasmodium falciparum malaria cases. In response, cartographic approaches have been developed that link maps of infection prevalence with mathematical relationships to predict the incidence rate of clinical malaria. Microsimulation (or 'agent-based') models represent a powerful new paradigm for defining such relationships; however, differences in model structure and calibration data mean that no consensus yet exists on the optimal form for use in disease-burden estimation. Here we develop a Bayesian statistical procedure combining functional regression-based model emulation with Markov Chain Monte Carlo sampling to calibrate three selected microsimulation models against a purpose-built data set of age-structured prevalence and incidence counts. This allows the generation of ensemble forecasts of the prevalence-incidence relationship stratified by age, transmission seasonality, treatment level and exposure history, from which we predict accelerating returns on investments in large-scale intervention campaigns as transmission and prevalence are progressively reduced. PMID:26348689

  10. Relationship between Plasmodium falciparum malaria prevalence, genetic diversity and endemic Burkitt lymphoma in Malawi.

    PubMed

    Johnston, W Thomas; Mutalima, Nora; Sun, David; Emmanuel, Benjamin; Bhatia, Kishor; Aka, Peter; Wu, Xiaolin; Borgstein, E; Liomba, G N; Kamiza, Steve; Mkandawire, Nyengo; Batumba, Mkume; Carpenter, Lucy M; Jaffe, Harold; Molyneux, Elizabeth M; Goedert, James J; Soppet, Daniel; Newton, Robert; Mbulaiteye, Sam M

    2014-01-01

    Endemic Burkitt lymphoma (eBL) has been linked to Plasmodium falciparum (Pf) malaria infection, but the contribution of infection with multiple Pf genotypes is uncertain. We studied 303 eBL (cases) and 274 non eBL-related cancers (controls) in Malawi using a sensitive and specific molecular-barcode array of 24 independently segregating Pf single nucleotide polymorphisms. Cases had a higher Pf malaria prevalence than controls (64.7% versus 45.3%; odds ratio [OR] 2.1, 95% confidence interval (CI): 1.5 to 3.1). Cases and controls were similar in terms of Pf density (4.9 versus 4.5 log copies, p = 0.28) and having ≥3 non-clonal calls (OR 2.7, 95% CI: 0.7-9.9, P = 0.14). However, cases were more likely to have a higher Pf genetic diversity score (153.9 versus 133.1, p = 0.036), which measures a combination of clonal and non-clonal calls, than controls. Further work is needed to evaluate the possible role of Pf genetic diversity in the pathogenesis of endemic BL.

  11. Nanovaccines for Malaria Using Plasmodium falciparum Antigen Pfs25 Attached Gold Nanoparticles

    PubMed Central

    Kumar, Rajesh; Ray, Paresh C.; Datta, Dibyadyuti; Bansal, Geetha P.; Angov, Evelina; Kumar, Nirbhay

    2015-01-01

    Malaria transmission-blocking vaccines (TBV) targeting sexual stages of the parasite represent an ideal intervention to reduce the burden of the disease and eventual elimination at the population level in endemic regions. Immune responses against sexual stage antigens impair the development of parasite inside the mosquitoes. Target antigens identified in Plasmodium falciparum include surface proteins Pfs230 and Pfs48/45 in male and female gametocytes and Pfs25 expressed in zygotes and ookinetes. The latter has undergone extensive evaluation in pre-clinical and phase I clinical trials and remains one of the leading target antigens for the development of TBV. Pfs25 has a complex tertiary structure characterized by four EGF-like repeat motifs formed by 11 disulfide bonds, and it has been rather difficult to obtain Pfs25 as a homogenous product in native conformation in any heterologous expression system. Recently, we have reported expression of codon-harmonized recombinant Pfs25 in E. coli (CHrPfs25) and which elicited highly potent malaria transmission-blocking antibodies in mice. In the current study, we investigated CHrPfs25 along with gold nanoparticles of different shapes, size and physicochemical properties as adjuvants for induction of transmission blocking immunity. The results revealed that CHrPfs25 delivered with various gold nanoparticles elicited strong transmission blocking antibodies and suggested that gold nanoparticles based formulations can be developed as nanovaccines to enhance the immunogenicity of vaccine antigens. PMID:26299750

  12. Enhanced Basophil Reactivities during Severe Malaria and Their Relationship with the Plasmodium falciparum Histamine-Releasing Factor Translationally Controlled Tumor Protein

    PubMed Central

    Pelleau, Stéphane; Diop, Sylvie; Dia Badiane, Méry; Vitte, Joana; Beguin, Pierre; Nato, Farida; Diop, Bernard M.; Bongrand, Pierre; Parzy, Daniel

    2012-01-01

    Recent studies suggest shared pathogenic pathways during malaria and allergy. Indeed, IgE, histamine, and the parasite-derived Plasmodium falciparum histamine-releasing factor translationally controlled tumor protein (PfTCTP) can be found at high levels in serum from patients experiencing malaria, but their relationship with basophil activation remains unknown. We recruited P. falciparum-infected patients in Senegal with mild malaria (MM; n = 19) or severe malaria (SM; n = 9) symptoms and healthy controls (HC; n = 38). Levels of serum IgE, PfTCTP, and IgG antibodies against PfTCTP were determined by enzyme-linked immunosorbent assays (ELISA). Basophil reactivities to IgE-dependent and -independent stimulations were measured ex vivo using fresh blood by looking at the expression level of the basophil activation marker CD203c with flow cytometry. Unstimulated basophils from MM had significantly lower levels of CD203c expression compared to those from HC and SM. After normalization on this baseline level, basophils from SM showed an enhanced reactivity to calcimycin (A23187) and hemozoin. Although SM reached higher median levels of activation after anti-IgE stimulation, great interindividual differences did not allow the results to reach statistical significance. When primed with recombinant TCTP before anti-IgE, qualitative differences in terms of a better ability to control excessive activation could be described for SM. IgE levels were very high in malaria patients, but concentrations in MM and SM were similar and were not associated with basophil responses, which demonstrates that the presence of IgE alone cannot explain the various basophil reactivities. Indeed, PfTCTP could be detected in 32% of patients, with higher concentrations for SM. These PfTCTP-positive patients displayed significantly higher basophil reactivities to any stimulus. Moreover, the absence of anti-PfTCTP IgG was associated with higher responses in SM but not MM. Our results show an

  13. Enhanced basophil reactivities during severe malaria and their relationship with the Plasmodium falciparum histamine-releasing factor translationally controlled tumor protein.

    PubMed

    Pelleau, Stéphane; Diop, Sylvie; Dia Badiane, Méry; Vitte, Joana; Beguin, Pierre; Nato, Farida; Diop, Bernard M; Bongrand, Pierre; Parzy, Daniel; Jambou, Ronan

    2012-08-01

    Recent studies suggest shared pathogenic pathways during malaria and allergy. Indeed, IgE, histamine, and the parasite-derived Plasmodium falciparum histamine-releasing factor translationally controlled tumor protein (PfTCTP) can be found at high levels in serum from patients experiencing malaria, but their relationship with basophil activation remains unknown. We recruited P. falciparum-infected patients in Senegal with mild malaria (MM; n = 19) or severe malaria (SM; n = 9) symptoms and healthy controls (HC; n = 38). Levels of serum IgE, PfTCTP, and IgG antibodies against PfTCTP were determined by enzyme-linked immunosorbent assays (ELISA). Basophil reactivities to IgE-dependent and -independent stimulations were measured ex vivo using fresh blood by looking at the expression level of the basophil activation marker CD203c with flow cytometry. Unstimulated basophils from MM had significantly lower levels of CD203c expression compared to those from HC and SM. After normalization on this baseline level, basophils from SM showed an enhanced reactivity to calcimycin (A23187) and hemozoin. Although SM reached higher median levels of activation after anti-IgE stimulation, great interindividual differences did not allow the results to reach statistical significance. When primed with recombinant TCTP before anti-IgE, qualitative differences in terms of a better ability to control excessive activation could be described for SM. IgE levels were very high in malaria patients, but concentrations in MM and SM were similar and were not associated with basophil responses, which demonstrates that the presence of IgE alone cannot explain the various basophil reactivities. Indeed, PfTCTP could be detected in 32% of patients, with higher concentrations for SM. These PfTCTP-positive patients displayed significantly higher basophil reactivities to any stimulus. Moreover, the absence of anti-PfTCTP IgG was associated with higher responses in SM but not MM. Our results show an

  14. Plasmodium falciparum Clearance Is Rapid and Pitting Independent in Immune Malian Children Treated With Artesunate for Malaria

    PubMed Central

    Ndour, Papa Alioune; Lopera-Mesa, Tatiana M.; Diakité, Seidina A. S.; Chiang, Serena; Mouri, Oussama; Roussel, Camille; Jauréguiberry, Stéphane; Biligui, Sylvestre; Kendjo, Eric; Claessens, Antoine; Ciceron, Liliane; Mazier, Dominique; Thellier, Marc; Diakité, Mahamadou; Fairhurst, Rick M.; Buffet, Pierre A.

    2015-01-01

    Background In Plasmodium falciparum–infected patients treated with artemisinins, parasitemia declines through so-called pitting, an innate splenic process that transforms infected red blood cells (iRBCs) into once-infected RBCs (O-iRBCs). Methods We measured pitting in 83 French travelers and 42 Malian children treated for malaria with artesunate. Results In travelers, O-iRBCs peaked at 107.7% initial parasitemia. In Malian children aged 1.5–4 years, O-iRBCs peaked at higher concentrations than in children aged 9–13 years (91.60% vs 31.95%; P = .0097). The parasite clearance time in older children was shorter than in younger children (P = .0001), and the decline in parasitemia in children aged 1.5–4 years often started 6 hours after treatment initiation, a lag phase generally absent in infants and older children. A 6-hour lag phase in artificial pitting of artesunate-exposed iRBCs was also observed in vitro. The proportion of iRBCs recognized by autologous immunoglobulin G (IgG) correlated with the parasite clearance time (r = −0.501; P = .0006) and peak O-iRBC concentration (r = −0.420; P = .0033). Conclusions Antimalarial immunity correlates with fast artemisinin-induced parasite clearance and low pitting rates. In nonimmune populations, artemisinin-induced P. falciparum clearance is related to pitting and starts after a 6-hour lag phase. In immune populations, passively and naturally acquired immune mechanisms operating faster than pitting may exist. This mechanism may mitigate the emergence of artemisinin-resistant P. falciparum in Africa. PMID:25183768

  15. In silico multiple-targets identification for heme detoxification in the human malaria parasite Plasmodium falciparum.

    PubMed

    Phaiphinit, Suthat; Pattaradilokrat, Sittiporn; Lursinsap, Chidchanok; Plaimas, Kitiporn

    2016-01-01

    Detoxification of hemoglobin byproducts or free heme is an essential step and considered potential targets for anti-malaria drug development. However, most of anti-malaria drugs are no longer effective due to the emergence and spread of the drug resistant malaria parasites. Therefore, it is an urgent need to identify potential new targets and even for target combinations for effective malaria drug design. In this work, we reconstructed the metabolic networks of Plasmodium falciparum and human red blood cells for the simulation of steady mass and flux flows of the parasite's metabolites under the blood environment by flux balance analysis (FBA). The integrated model, namely iPF-RBC-713, was then adjusted into two stage-specific metabolic models, which first was for the pathological stage metabolic model of the parasite when invaded the red blood cell without any treatment and second was for the treatment stage of the parasite when a drug acted by inhibiting the hemozoin formation and caused high production rate of heme toxicity. The process of identifying target combinations consisted of two main steps. Firstly, the optimal fluxes of reactions in both the pathological and treatment stages were computed and compared to determine the change of fluxes. Corresponding enzymes of the reactions with zero fluxes in the treatment stage but non-zero fluxes in the pathological stage were predicted as a preliminary list of potential targets in inhibiting heme detoxification. Secondly, the combinations of all possible targets listed in the first step were examined to search for the best promising target combinations resulting in more effective inhibition of the detoxification to kill the malaria parasites. Finally, twenty-three enzymes were identified as a preliminary list of candidate targets which mostly were in pyruvate metabolism and citrate cycle. The optimal set of multiple targets for blocking the detoxification was a set of heme ligase, adenosine transporter, myo

  16. Malaria among patients and aid workers consulting a primary healthcare centre in Leogane, Haiti, November 2010 to February 2011 - a prospective observational study.

    PubMed

    Neuberger, A; Zaulan, O; Tenenboim, S; Vernet, S; Pex, R; Held, K; Urman, M; Garpenfeldt, K; Schwartz, E

    2011-01-01

    Plasmodium falciparum malaria is endemic in Haiti, but epidemiological data are scarce. A total of 61 cases of malaria were diagnosed between November 2010 and February 2011 among 130 Haitian patients with undifferentiated fever. Three additional cases were diagnosed in expatriates not taking the recommended chemoprophylaxis. No cases were diagnosed among aid workers using chemoprophylaxis. In conclusion, malaria is a significant health problem in Leogane, Haiti. Aid workers and visitors should use chemoprophylaxis according to existing guidelines.

  17. Oral artesunate-amodiaquine and artemether-lumefantrine in the treatment of uncomplicated hyperparasitaemic Plasmodium falciparum malaria in children.

    PubMed

    Gbotosho, Grace O; Sowunmi, Akintunde; Okuboyejo, Titilope M; Happi, Christian T

    2012-04-01

    The therapeutic efficacy, changes in haematocrit and declines in parasitaemias were evaluated in 56 children with uncomplicated falciparum hyperparasitaemia after oral artesunate-amodiaquine or artemether-lumefantrine. All children recovered clinically within 2 days and without progression to severe malaria. Falls in haematocrit in the first 3 days after treatment began were similar and <5%. Declines in parasitaemias were monoexponential with both treatments with an estimated half-life of 1 h.

  18. Plasmodium falciparum-like parasites infecting wild apes in southern Cameroon do not represent a recurrent source of human malaria

    PubMed Central

    Sundararaman, Sesh A.; Liu, Weimin; Keele, Brandon F.; Learn, Gerald H.; Bittinger, Kyle; Mouacha, Fatima; Ahuka-Mundeke, Steve; Manske, Magnus; Sherrill-Mix, Scott; Li, Yingying; Malenke, Jordan A.; Delaporte, Eric; Laurent, Christian; Mpoudi Ngole, Eitel; Kwiatkowski, Dominic P.; Shaw, George M.; Rayner, Julian C.; Peeters, Martine; Sharp, Paul M.; Bushman, Frederic D.; Hahn, Beatrice H.

    2013-01-01

    Wild-living chimpanzees and gorillas harbor a multitude of Plasmodium species, including six of the subgenus Laverania, one of which served as the progenitor of Plasmodium falciparum. Despite the magnitude of this reservoir, it is unknown whether apes represent a source of human infections. Here, we used Plasmodium species-specific PCR, single-genome amplification, and 454 sequencing to screen humans from remote areas of southern Cameroon for ape Laverania infections. Among 1,402 blood samples, we found 1,000 to be Plasmodium mitochondrial DNA (mtDNA) positive, all of which contained human parasites as determined by sequencing and/or restriction enzyme digestion. To exclude low-abundance infections, we subjected 514 of these samples to 454 sequencing, targeting a region of the mtDNA genome that distinguishes ape from human Laverania species. Using algorithms specifically developed to differentiate rare Plasmodium variants from 454-sequencing error, we identified single and mixed-species infections with P. falciparum, Plasmodium malariae, and/or Plasmodium ovale. However, none of the human samples contained ape Laverania parasites, including the gorilla precursor of P. falciparum. To characterize further the diversity of P. falciparum in Cameroon, we used single-genome amplification to amplify 3.4-kb mtDNA fragments from 229 infected humans. Phylogenetic analysis identified 62 new variants, all of which clustered with extant P. falciparum, providing further evidence that P. falciparum emerged following a single gorilla-to-human transmission. Thus, unlike Plasmodium knowlesi-infected macaques in southeast Asia, African apes harboring Laverania parasites do not seem to serve as a recurrent source of human malaria, a finding of import to ongoing control and eradication measures. PMID:23569255

  19. A population pharmacokinetic model of piperaquine in pregnant and non-pregnant women with uncomplicated Plasmodium falciparum malaria in Sudan

    PubMed Central

    2012-01-01

    Background Pregnancy is associated with an increased risk of developing a malaria infection and a higher risk of developing severe malaria. The pharmacokinetic properties of many anti-malarials are also altered during pregnancy, often resulting in a decreased drug exposure. Piperaquine is a promising anti-malarial partner drug used in a fixed-dose combination with dihydroartemisinin. The aim of this study was to investigate the population pharmacokinetics of piperaquine in pregnant and non-pregnant Sudanese women with uncomplicated Plasmodium falciparum malaria. Method Symptomatic patients received a standard dose regimen of the fixed dose oral piperaquine-dihydroartemisinin combination treatment. Densely sampled plasma aliquots were collected and analysed using a previously described LC-MS/MS method. Data from 12 pregnant and 12 non-pregnant women were analysed using nonlinear mixed-effects modelling. A Monte Carlo Mapped Power (MCMP) analysis was conducted based on a previously published study to evaluate the power of detecting covariates in this relatively small study. Results A three-compartment disposition model with a transit-absorption model described the observed data well. Body weight was added as an allometric function on all clearance and volume parameters. A statistically significant decrease in estimated terminal piperaquine half-life in pregnant compared with non-pregnant women was found, but there were no differences in post-hoc estimates of total piperaquine exposure. The MCMP analysis indicated a minimum of 13 pregnant and 13 non-pregnant women were required to identify pregnancy as a covariate on relevant pharmacokinetic parameters (80% power and p=0.05). Pregnancy was, therefore, evaluated as a categorical and continuous covariate (i.e. estimate gestational age) in a full covariate approach. Using this approach pregnancy was not associated with any major change in piperaquine elimination clearance. However, a trend of increasing elimination

  20. Hemolysis after Oral Artemisinin Combination Therapy for Uncomplicated Plasmodium falciparum Malaria

    PubMed Central

    Lingscheid, Tilman; Steiner, Florian; Stegemann, Miriam S.; Bélard, Sabine; Menner, Nikolai; Pongratz, Peter; Kim, Johanna; von Bernuth, Horst; Mayer, Beate; Damm, Georg; Seehofer, Daniel; Salama, Abdulgabar; Suttorp, Norbert; Zoller, Thomas

    2016-01-01

    Episodes of delayed hemolysis 2–6 weeks after treatment of severe malaria with intravenous artesunate have been described. We performed a prospective observational study of patients with uncomplicated malaria to investigate whether posttreatment hemolysis also occurs after oral artemisinin-based combination therapy. Eight of 20 patients with uncomplicated malaria who were given oral artemisinin-based combination therapy met the definition of posttreatment hemolysis (low haptoglobin level and increased lactate dehydrogenase level on day 14). Five patients had hemolysis persisting for 1 month. Patients with posttreatment hemolysis had a median decrease in hemoglobin level of 1.3 g/dL (interquartile range 0.3–2.0 g/dL) in the posttreatment period, and patients without posttreatment hemolysis had a median increase of 0.3 g/dL (IQR −0.1 to 0.7 g/dL; p = 0.002). These findings indicate a need for increased vigilance for hemolytic events in malaria patients, particularly those with predisposing factors for anemia. PMID:27434054

  1. Patterns and dynamics of genetic diversity in Plasmodium falciparum: what past human migrations tell us about malaria.

    PubMed

    Mita, Toshihiro; Jombart, Thibaut

    2015-06-01

    Plasmodium falciparum is the main agent of malaria, one of the major human infectious diseases affecting millions of people worldwide. The genetic diversity of P. falciparum populations is an essential factor in the parasite's ability to adapt to changes in its environment, enabling the development of drug resistance and the evasion from the host immune system through antigenic variation. Therefore, characterizing these patterns and understanding the main drivers of the pathogen's genetic diversity can provide useful inputs for informing control strategies. In this paper, we review the pioneering work led by Professor Kazuyuki Tanabe on the genetic diversity of P. falciparum populations. In a first part, we recall basic results from population genetics for quantifying within-population genetic diversity, and discuss the main mechanisms driving this diversity. Then, we show how these approaches have been used for reconstructing the historical spread of malaria worldwide, and how current patterns of genetic diversity suggest that the pathogen followed our ancestors in their journey out of Africa. Because these results are robust to different types of genetic markers, they provide a baseline for predicting the pathogen's diversity in unsampled populations, and some useful elements for predicting vaccine efficacy and informing malaria control strategies.

  2. Genotyping of chloroquine resistant Plasmodium falciparum in wild caught Anopheles minimus mosquitoes in a malaria endemic area of Assam, India.

    PubMed

    Sarma, D K; Mohapatra, P K; Bhattacharyya, D R; Mahanta, J; Prakash, A

    2014-09-01

    We validated the feasibility of using Plasmodium falciparum, the human malaria parasite, DNA present in wild caught vector mosquitoes for the characterization of chloroquine resistance status. House frequenting mosquitoes belonging to Anopheles minimus complex were collected from human dwellings in a malaria endemic area of Assam, Northeast India and DNA was extracted from the head-thorax region of individual mosquitoes. Anopheles minimus complex mosquitoes were identified to species level and screened for the presence of Plasmodium sp. using molecular tools. Nested PCR-RFLP method was used for genotyping of P. falciparum based on K76T mutation in the chloroquine resistance transporter (pfcrt) gene. Three of the 27 wild caught An. minimus mosquitoes were harbouring P. falciparum sporozoites (positivity 11.1%) and all 3 were had 76T mutation in the pfcrt gene, indicating chloroquine resistance. The approach of characterizing antimalarial resistance of malaria parasite in vector mosquitoes can potentially be used as a surveillance tool for monitoring transmission of antimalarial drug resistant parasite strains in the community.

  3. Infectivity of Plasmodium falciparum in Malaria-Naive Individuals Is Related to Knob Expression and Cytoadherence of the Parasite.

    PubMed

    Stanisic, Danielle I; Gerrard, John; Fink, James; Griffin, Paul M; Liu, Xue Q; Sundac, Lana; Sekuloski, Silvana; Rodriguez, Ingrid B; Pingnet, Jolien; Yang, Yuedong; Zhou, Yaoqi; Trenholme, Katharine R; Wang, Claire Y T; Hackett, Hazel; Chan, Jo-Anne A; Langer, Christine; Hanssen, Eric; Hoffman, Stephen L; Beeson, James G; McCarthy, James S; Good, Michael F

    2016-09-01

    Plasmodium falciparum is the most virulent human malaria parasite because of its ability to cytoadhere in the microvasculature. Nonhuman primate studies demonstrated relationships among knob expression, cytoadherence, and infectivity. This has not been examined in humans. Cultured clinical-grade P. falciparum parasites (NF54, 7G8, and 3D7B) and ex vivo-derived cell banks were characterized. Knob and knob-associated histidine-rich protein expression, CD36 adhesion, and antibody recognition of parasitized erythrocytes (PEs) were evaluated. Parasites from the cell banks were administered to malaria-naive human volunteers to explore infectivity. For the NF54 and 3D7B cell banks, blood was collected from the study participants for in vitro characterization. All parasites were infective in vivo However, infectivity of NF54 was dramatically reduced. In vitro characterization revealed that unlike other cell bank parasites, NF54 PEs lacked knobs and did not cytoadhere. Recognition of NF54 PEs by immune sera was observed, suggesting P. falciparum erythrocyte membrane protein 1 expression. Subsequent recovery of knob expression and CD36-mediated adhesion were observed in PEs derived from participants infected with NF54. Knobless cell bank parasites have a dramatic reduction in infectivity and the ability to adhere to CD36. Subsequent infection of malaria-naive volunteers restored knob expression and CD36-mediated cytoadherence, thereby showing that the human environment can modulate virulence.

  4. A country-wide malaria survey in Mozambique. I. Plasmodium falciparum infection in children in different epidemiological settings

    PubMed Central

    Mabunda, Samuel; Casimiro, Sónia; Quinto, Llorenç; Alonso, Pedro

    2008-01-01

    Background Across tropical Africa the bulk of malaria-related morbidity and mortality is particularly high during childhood. Classical malariometric surveys have relied on assessing malaria infection prevalence. The last comprehensive evaluation of the malaria situation in Mozambique was carried out during the 1950s. This study aims to characterize the malaria transmission intensities and to estimate the disease burden that may help guide control programme. Methods Between February 2002 and April 2003, a house-to-house survey, was carried out in 24 districts randomly selected. A total of 8,816 children aged below 10 years old were enrolled. Finger prick and blood collection were performed to prepare thick and thin films for malaria parasite species identification, density and haemoglobin concentration. Axillary temperature was also measured. Prevalence of infection, parasite density and anaemia were estimated for age groups category in each region/stratum. Comparisons between proportions were made using Chi-square test or Fisher exact. Relationship between age groups, region/stratum and parasite prevalence, density was determined using linear regression. All survey mean estimations were adjusted for sampling weights, clustering and stratification. Results Malaria parasite prevalence was 58.9% (5.190/8.816), the majority of blood smears 52.4% (4,616/8,816) were due to Plasmodium falciparum and geometric mean parasite density was 1,211 parasites/μl (95% CI, 1,141 – 1.286). Gametocytes prevalence, only for P. falciparum was 5.6% (518/8,816). The burden was highest in the northern regions and in the coastal stratum. Parasite infection and geometric mean parasite density peaked during the second year of life and thereafter decreased with increasing age. Mean haemoglobin concentrations was 9.9 g/dl (95% CI 9.5 – 10.2). Anaemia prevalence was 69.8% (6.257/8.816) and among anaemic children 11.5% (743/6.257) were severely anaemic. Anaemia rose dramatically during the

  5. Platelet-mediated clumping of Plasmodium falciparum-infected erythrocytes is a common adhesive phenotype and is associated with severe malaria

    PubMed Central

    Pain, Arnab; Ferguson, David J. P.; Kai, Oscar; Urban, Britta C.; Lowe, Brett; Marsh, Kevin; Roberts, David J.

    2001-01-01

    Sequestration of malaria-infected erythrocytes in the peripheral circulation has been associated with the virulence of Plasmodium falciparum. Defining the adhesive phenotypes of infected erythrocytes may therefore help us to understand how severe disease is caused and how to prevent or treat it. We have previously shown that malaria-infected erythrocytes may form apparent autoagglutinates of infected erythrocytes. Here we show that such autoagglutination of a laboratory line of P. falciparum is mediated by platelets and that the formation of clumps of infected erythrocytes and platelets requires expression of the platelet surface glycoprotein CD36. Platelet-dependent clumping is a distinct adhesive phenotype, expressed by some but not all CD36-binding parasite lines, and is common in field isolates of P. falciparum. Finally, we have established that platelet-mediated clumping is strongly associated with severe malaria. Precise definition of the molecular basis of this intriguing adhesive phenotype may help to elucidate the complex pathophysiology of malaria. PMID:11172032

  6. Categorical complexities of Plasmodium falciparum malaria in individuals is associated with genetic variations in ADORA2A and GRK5 genes.

    PubMed

    Gupta, Himanshu; Jain, Aditya; Saadi, Abdul Vahab; Vasudevan, Thanvanthri G; Hande, Manjunath H; D'Souza, Sydney C; Ghosh, Susanta K; Umakanth, Shashikiran; Satyamoorthy, Kapaettu

    2015-08-01

    In the erythrocytes, malaria parasite entry and infection is mediated through complex membrane sorting and signaling processes. We investigated the effects of single-locus and multilocus interactions to test the hypothesis that the members of the GPCR family genes, adenosine A2a receptor (ADORA2A) and G-protein coupled receptor kinase5 (GRK5), may contribute to the pathogenesis of malaria caused by Plasmodium falciparum (Pf) independently or through complex interactions. In a case-control study of adults, individuals affected by Pf malaria (complicated n=168; uncomplicated n=282) and healthy controls (n=450) were tested for their association to four known SNPs in GRK5 (rs2230345, rs2275036, rs4752307 and rs11198918) and two in ADORA2A (rs9624472 and rs5751876) genes with malaria susceptibility, using techniques of polymerase chain reaction-restriction fragment length polymorphisms and direct DNA sequencing. Single-locus analysis showed significant association of 2 SNPs; rs5751876 (OR=3.2(2.0-5.2); p=0.0006) of ADORA2A and rs2230345 (OR=0.3(0.2-0.5); p=0.0006) of GRK5 with malaria. The mean of the serum creatinine levels were significantly higher in patients with variant GG (p=0.006) of rs9624472 in ADORA2A gene compared to AA and AG genotypes in complicated Pf malaria cases, with the G allele also showing increased risk for malaria (OR=1.3(1.1-1.6); p=0.017). Analyses of predicted haplotypes of the two ADORA2A and the four GRK5 SNPs have identified the haplotypes that conferred risk as well as resistance to malaria with statistical significance. Molecular docking analysis of evolutionary rs2230345 SNP indicated a stable activity of GRK5 for the mutant allele compared to the wild type. Further, generalized multifactor dimensionality reduction to test the contribution of individual effects of the six polymorphisms and higher-order interactions to risk of symptoms/clinical complications of malaria suggested a best six-locus model showing statistical significance. The

  7. Functional deficit of T regulatory cells in Fulani, an ethnic group with low susceptibility to Plasmodium falciparum malaria

    PubMed Central

    Torcia, Maria G.; Santarlasci, Veronica; Cosmi, Lorenzo; Clemente, AnnMaria; Maggi, Laura; Mangano, Valentina D.; Verra, Federica; Bancone, Germana; Nebie, Issa; Sirima, Bienvenu Sodiomon; Liotta, Francesco; Frosali, Francesca; Angeli, Roberta; Severini, Carlo; Sannella, Anna R.; Bonini, Paolo; Lucibello, Maria; Maggi, Enrico; Garaci, Enrico; Coluzzi, Mario; Cozzolino, Federico; Annunziato, Francesco; Romagnani, Sergio; Modiano, David

    2008-01-01

    Previous interethnic comparative studies on the susceptibility to malaria performed in West Africa showed that Fulani are more resistant to Plasmodium falciparum malaria than are sympatric ethnic groups. This lower susceptibility is not associated to classic malaria-resistance genes, and the analysis of the immune response to P. falciparum sporozoite and blood stage antigens, as well as non-malaria antigens, revealed higher immune reactivity in Fulani. In the present study we compared the expression profile of a panel of genes involved in immune response in peripheral blood mononuclear cells (PBMC) from Fulani and sympatric Mossi from Burkina Faso. An increased expression of T helper 1 (TH1)-related genes (IL-18, IFNγ, and TBX21) and TH2-related genes (IL-4 and GATA3) and a reduced expression of genes distinctive of T regulatory activity (CTLA4 and FOXP3) were observed in Fulani. Microarray analysis on RNA from CD4+CD25+ (T regulatory) cells, performed with a panel of cDNA probes specific for 96 genes involved in immune modulation, indicated obvious differences between the two ethnic groups with 23% of genes, including TGFβ, TGFβRs, CTLA4, and FOXP3, less expressed in Fulani compared with Mossi and European donors not exposed to malaria. As further indications of a low T regulatory cell activity, Fulani showed lower serum levels of TGFβ and higher concentrations of the proinflammatory chemokines CXCL10 and CCL22 compared with Mossi; moreover, the proliferative response of Fulani to malaria antigens was not affected by the depletion of CD25+ regulatory cells whereas that of Mossi was significantly increased. The results suggest that the higher resistance to malaria of the Fulani could derive from a functional deficit of T regulatory cells. PMID:18174328

  8. Genetic red cell disorders and severity of falciparum malaria in Myanmar.

    PubMed Central

    Oo, M.; Tin-Shwe; Marlar-Than; O'Sullivan, W. J.

    1995-01-01

    A hospital-based survey was undertaken to investigate the relationship between the incidence and severity of malaria infection and various red cell disorders in Myanmar. The mean parasitaemia levels of patients with alpha- or beta-thalassaemia trait or with severe glucose-6-phosphate dehydrogenase (G6PD) deficiency were lower than those of individuals with normal haemoglobin AA or with heterozygous haemoglobin E. The double genetic defect of thalassaemia trait and severe G6PD deficiency appeared to confer some degree of protection against malaria. PMID:8846492

  9. Declining Efficacy of Artemisinin Combination Therapy Against P. Falciparum Malaria on the Thai–Myanmar Border (2003–2013): The Role of Parasite Genetic Factors

    PubMed Central

    Phyo, Aung Pyae; Ashley, Elizabeth A.; Anderson, Tim J. C.; Bozdech, Zbynek; Carrara, Verena I.; Sriprawat, Kanlaya; Nair, Shalini; White, Marina McDew; Dziekan, Jerzy; Ling, Clare; Proux, Stephane; Konghahong, Kamonchanok; Jeeyapant, Atthanee; Woodrow, Charles J.; Imwong, Mallika; McGready, Rose; Lwin, Khin Maung; Day, Nicholas P. J.; White, Nicholas J.; Nosten, Francois

    2016-01-01

    Background. Deployment of mefloquine–artesunate (MAS3) on the Thailand–Myanmar border has led to a sustained reduction in falciparum malaria, although antimalarial efficacy has declined substantially in recent years. The role of Plasmodium falciparum K13 mutations (a marker of artemisinin resistance) in reducing treatment efficacy remains controversial. Methods. Between 2003 and 2013, we studied the efficacy of MAS3 in 1005 patients with uncomplicated P. falciparum malaria in relation to molecular markers of resistance. Results. Polymerase chain reaction (PCR)–adjusted cure rates declined from 100% in 2003 to 81.1% in 2013 as the proportions of isolates with multiple Pfmdr1 copies doubled from 32.4% to 64.7% and those with K13 mutations increased from 6.7% to 83.4%. K13 mutations conferring moderate artemisinin resistance (notably E252Q) predominated initially but were later overtaken by propeller mutations associated with slower parasite clearance (notably C580Y). Those infected with both multiple Pfmdr1 copy number and a K13 propeller mutation were 14 times more likely to fail treatment. The PCR-adjusted cure rate was 57.8% (95% confidence interval [CI], 45.4, 68.3) compared with 97.8% (95% CI, 93.3, 99.3) in patients with K13 wild type and Pfmdr1 single copy. K13 propeller mutation alone was a strong risk factor for recrudescence (P = .009). The combined population attributable fraction of recrudescence associated with K13 mutation and Pfmdr1 amplification was 82%. Conclusions. The increasing prevalence of K13 mutations was the decisive factor for the recent and rapid decline in efficacy of artemisinin-based combination (MAS3) on the Thailand–Myanmar border. PMID:27313266

  10. Plasmodium falciparum Merozoite Surface Protein-1 Polymorphisms among Asymptomatic Sickle Cell Anemia Patients in Nigeria.

    PubMed

    Bamidele Abiodun, Iwalokun; Oluwadun, Afolabi; Olugbenga Ayoola, Aina; Senapon Olusola, Iwalokun

    2016-01-01

    Asymptomatic malaria (ASM) has been implicated in the development of hemolytic crisis in infected sickle cell anemia (SCA) patients worldwide. This study surveyed steady state SCA Nigerian patients for ASM to investigate the influence of malaria prevention behaviors and age on parasitaemia and multiplicity of infection (MOI). A total of 78 steady SCA patients aged 5 - 27 years on routine care at three health facilities in Lagos were investigated for ASM by light microscopy and PCR with a multiplicity of infection determined by genotyping block 2 of merozoite surface protein 1 (msp1) gene of Plasmodium falciparum (P. falciparum). Use of malaria prevention measures was captured using a semi-structured questionnaire. The prevalence rates of ASM (due to Pf only) by microscopy and PCR were found to be 27.3% and 47.4% respectively (P < 0.05) with a Mean + SEM parasite density of 2238.4 + 464.3 parasites/uL. Five distinct msp1 genotypes [K1 (2), MAD20 (2), RO33 (1)] were detected and significant (P<0.05) disparity in allele frequencies (K1, 91.8%, MAD20, 32.4%; RO33, 18.9%) was found. The overall MOI was 1.43 and 37.8% of infections were polyclonal (P<0.05). ASM was associated with non-use of preventive measures and occurred in 62.1% of SCA patients aged < 10y with lower MOI of 1.3 compared to 38.1% in older patients with a higher MOI of 1.5 (P<0.05). We conclude that PCR improved the diagnosis of ASM among Nigerian SCA patients with infections being of low complexity and associated with non-use of preventive interventions and R033 msp1 allele selection. PMID:26853290

  11. Serological Conservation of Parasite-Infected Erythrocytes Predicts Plasmodium falciparum Erythrocyte Membrane Protein 1 Gene Expression but Not Severity of Childhood Malaria.

    PubMed

    Warimwe, George M; Abdi, Abdirahman I; Muthui, Michelle; Fegan, Gregory; Musyoki, Jennifer N; Marsh, Kevin; Bull, Peter C

    2016-05-01

    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), expressed on P. falciparum-infected erythrocytes, is a major family of clonally variant targets of naturally acquired immunity to malaria. Previous studies have demonstrated that in areas where malaria is endemic, antibodies to infected erythrocytes from children with severe malaria tend to be more seroprevalent than antibodies to infected erythrocytes from children with nonsevere malaria. These data have led to a working hypothesis that PfEMP1 variants associated with parasite virulence are relatively conserved in structure. However, the longevity of such serologically conserved variants in the parasite population is unknown. Here, using infected erythrocytes from recently sampled clinical P. falciparum samples, we measured serological conservation using pools of antibodies in sera that had been sampled 10 to 12 years earlier. The serological conservation of infected erythrocytes strongly correlated with the expression of specific PfEMP1 subsets previously found to be associated with severe malaria. However, we found no association between serological conservation per se and disease severity within these data. This contrasts with the simple hypothesis that P. falciparum isolates with a serologically conserved group of PfEMP1 variants cause severe malaria. The data are instead consistent with periodic turnover of the immunodominant epitopes of PfEMP1 associated with severe malaria.

  12. Lumefantrine and Desbutyl-Lumefantrine Population Pharmacokinetic-Pharmacodynamic Relationships in Pregnant Women with Uncomplicated Plasmodium falciparum Malaria on the Thailand-Myanmar Border.

    PubMed

    Kloprogge, Frank; McGready, Rose; Hanpithakpong, Warunee; Blessborn, Daniel; Day, Nicholas P J; White, Nicholas J; Nosten, François; Tarning, Joel

    2015-10-01

    Artemether-lumefantrine is the most widely used antimalarial artemisinin-based combination treatment. Recent studies have suggested that day 7 plasma concentrations of the potent metabolite desbutyl-lumefantrine correlate better with treatment outcomes than those of lumefantrine. Low cure rates have been reported in pregnant women with uncomplicated falciparum malaria treated with artemether-lumefantrine in northwest Thailand. A simultaneous pharmacokinetic drug-metabolite model was developed based on dense venous and sparse capillary lumefantrine and desbutyl-lumefantrine plasma samples from 116 pregnant patients on the Thailand-Myanmar border. The best model was used to evaluate therapeutic outcomes with a time-to-event approach. Lumefantrine and desbutyl-lumefantrine concentrations, implemented in an Emax model, both predicted treatment outcomes, but lumefantrine provided better predictive power. A combined model including both lumefantrine and desbutyl-lumefantrine did not improve the model further. Simulations suggested that cure rates in pregnant women with falciparum malaria could be increased by prolonging the treatment course. (These trials were registered at controlled-trials.com [ISRCTN 86353884].).

  13. Lumefantrine and Desbutyl-Lumefantrine Population Pharmacokinetic-Pharmacodynamic Relationships in Pregnant Women with Uncomplicated Plasmodium falciparum Malaria on the Thailand-Myanmar Border

    PubMed Central

    Kloprogge, Frank; McGready, Rose; Hanpithakpong, Warunee; Blessborn, Daniel; Day, Nicholas P. J.; White, Nicholas J.; Nosten, François

    2015-01-01

    Artemether-lumefantrine is the most widely used antimalarial artemisinin-based combination treatment. Recent studies have suggested that day 7 plasma concentrations of the potent metabolite desbutyl-lumefantrine correlate better with treatment outcomes than those of lumefantrine. Low cure rates have been reported in pregnant women with uncomplicated falciparum malaria treated with artemether-lumefantrine in northwest Thailand. A simultaneous pharmacokinetic drug-metabolite model was developed based on dense venous and sparse capillary lumefantrine and desbutyl-lumefantrine plasma samples from 116 pregnant patients on the Thailand-Myanmar border. The best model was used to evaluate therapeutic outcomes with a time-to-event approach. Lumefantrine and desbutyl-lumefantrine concentrations, implemented in an Emax model, both predicted treatment outcomes, but lumefantrine provided better predictive power. A combined model including both lumefantrine and desbutyl-lumefantrine did not improve the model further. Simulations suggested that cure rates in pregnant women with falciparum malaria could be increased by prolonging the treatment course. (These trials were registered at controlled-trials.com [ISRCTN 86353884].) PMID:26239986

  14. Persistent ICT malaria P.f/P.v panmalarial and HRP2 antigen reactivity after treatment of Plasmodium falciparum malaria is associated with gametocytemia and results in false-positive diagnoses of Plasmodium vivax in convalescence.

    PubMed

    Tjitra, E; Suprianto, S; McBroom, J; Currie, B J; Anstey, N M

    2001-03-01

    A problem with rapid Plasmodium falciparum-specific antigen histidine-rich protein 2 (HRP2) detection tests for malaria is the persistence of antigen in blood after the disappearance of asexual-stage parasitemia and clinical symptoms, resulting in false-positive (FP) test results following treatment. The ICT P.f/P.v immunochromatographic test detects both HRP2 and a panmalarial antigen (PMA) found in both P. falciparum and Plasmodium vivax. To examine posttreatment antigen persistence with this test and whether persistent sexual-stage forms (gametocytes) are a cause of FP tests after treatment, we compared serial antigen test results with microscopy results from patients symptomatic with P. falciparum malaria in Indonesia for 28 days following treatment with chloroquine (CQ; n = 66), sulfadoxine-pyrimethamine (SP; n = 36), and artesunate plus sulfadoxine-pyrimethamine (ART + SP; n = 15). Persistent FP antigenemia following SP treatment occurred in 29% (HRP2) and 42% (PMA) of the patients on day 7 and in 10% (HRP2) and 23% (PMA) on day 14. The high rates of persistent HRP2 and PMA antigenemia following CQ and SP treatment were strongly associated with the presence of gametocytemia, with the proportion with gametocytes on day 7 posttreatment being significantly greater in those with FP results than in those with true-negative PMA and HRP2 results. Gametocyte frequency on day 14 post-SP treatment was also greater in those with FP PMA results. Following SP treatment, PMA persisted longer than HRP2, giving an FP diagnosis of P. vivax in up to 16% of patients on day 14, with all FP P. vivax diagnoses having gametocytemia. In contrast, PMA was rapidly cleared following ART + SP treatment in association with rapid clearance of gametocytemia. Gametocytes appear to be an important cause of persistent posttreatment panmalarial antigenemia in areas of endemicity and may also contribute in part to persistent HRP2 antigenemia following treatment. PMID:11230422

  15. Activity of Herbal Medicines on Plasmodium falciparum Gametocytes: Implications for Malaria Transmission in Ghana

    PubMed Central

    Amoah, Linda Eva; Kakaney, Courage; Kwansa-Bentum, Bethel; Kusi, Kwadwo Asamoah

    2015-01-01

    Background Malaria still remains a major health issue in Ghana despite the introduction of Artemisinin-based combination therapy (ACT) coupled with other preventative measures such as the use of insecticide treated nets (ITNs). The global quest for eradication of malaria has heightened the interest of identifying drugs that target the sexual stage of the parasite, referred to as transmission-blocking drugs. This study aimed at assessing the efficacy and gametocydal effects of some commonly used herbal malaria products in Ghana. Methodology/Principal Findings After identifying herbal anti-malarial products frequently purchased on the Ghanaian market, ten of them were selected and lyophilized. In vitro drug sensitivity testing of different concentrations of the herbal products was carried out on asexual and in vitro generated gametocytes of the 3D7 strain of Plasmodium falciparum. The efficacies of the products were assessed by microscopy. Cultures containing low dose of RT also produced the least number of late stage gametocytes. Two of the herbal products CM and RT inhibited the growth of late stage gametocytes by > 80% at 100 μg/ml whilst KG was the most inhibitory to early stage gametocytes at that same concentration. However at 1 μg/ml, only YF significantly inhibited the survival of late stage gametocytes although at that same concentration YF barely inhibited the survival of early stage gametocytes. Conclusions/Significance Herbal product RT (Aloe schweinfurthii, Khaya senegalensis, Piliostigma thonningii and Cassia siamea) demonstrated properties of a highly efficacious gametocydal product. Low dose of herbal product RT exhibited the highest gametocydal activity and at 100 μg/ml, RT exhibited >80% inhibition of late stage gametocytes. However inhibition of asexual stage parasite by RT was not optimal. Improving the asexual inhibition of RT could convert RT into an ideal antimalarial herbal product. We also found that generally C. sanguinolenta containing

  16. Selective killing of the human malaria parasite Plasmodium falciparum by a benzylthiazolium dye.

    PubMed

    Kelly, Jane X; Winter, Rolf W; Braun, Theodore P; Osei-Agyemang, Myralyn; Hinrichs, David J; Riscoe, Michael K

    2007-06-01

    Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium. The most virulent form of the disease is caused by Plasmodium falciparum which infects hundreds of millions of people and is responsible for the deaths of 1-2 million individuals each year. An essential part of the parasitic process is the remodeling of the red blood cell membrane and its protein constituents to permit a higher flux of nutrients and waste products into or away from the intracellular parasite. Much of this increased permeability is due to a single type of broad specificity channel variously called the new permeation pathway (NPP), the nutrient channel, and the Plasmodial surface anion channel (PSAC). This channel is permeable to a range of low molecular weight solutes both charged and uncharged, with a strong preference for anions. Drugs such as furosemide that are known to block anion-selective channels inhibit PSAC. In this study, we have investigated a dye known as benzothiocarboxypurine, BCP, which had been studied as a possible diagnostic aid given its selective uptake by P. falciparum infected red cells. We found that the dye enters parasitized red cells via the furosemide-inhibitable PSAC, forms a brightly fluorescent complex with parasite nucleic acids, and is selectively toxic to infected cells. Our study describes an antimalarial agent that exploits the altered permeability of Plasmodium-infected red cells as a means to killing the parasite and highlights a chemical reagent that may prove useful in high throughput screening of compounds for inhibitors of the channel.

  17. Evidence of a Mild Mutator Phenotype in Cambodian Plasmodium falciparum Malaria Parasites.

    PubMed

    Lee, Andrew H; Fidock, David A

    2016-01-01

    Malaria control efforts have been continuously stymied by drug-resistant strains of Plasmodium falciparum, which typically originate in Southeast Asia prior to spreading into high-transmission settings in Africa. One earlier proposed explanation for Southeast Asia being a hotbed of resistance has been the hypermutability or "Accelerated Resistance to Multiple Drugs" (ARMD) phenotype, whereby multidrug-resistant Southeast Asian parasites were reported to exhibit 1,000-fold higher rates of resistance to unrelated antimalarial agents when compared to drug-sensitive parasites. However, three recent studies do not recapitulate this hypermutability phenotype. Intriguingly, genome sequencing of recently derived multidrug-resistant Cambodian isolates has identified a high proportion of DNA repair gene mutations in multidrug-resistant parasites, suggesting their potential role in shaping local parasite evolution. By adapting fluctuation assays for use in P. falciparum, we have examined the in vitro mutation rates of five recent Cambodian isolates and three reference laboratory strains. For these studies we also generated a knockout parasite line lacking the DNA repair factor Exonuclease I. In these assays, parasites were typed for their ability to acquire resistance to KAE609, currently in advanced clinical trials, yielding 13 novel mutations in the Na+/H+-ATPase PfATP4, the primary resistance determinant. We observed no evidence of hypermutability. Instead, we found evidence of a mild mutator (up to a 3.4-fold increase in mutation rate) phenotype in two artemisinin-resistant Cambodian isolates, which carry DNA repair gene mutations. We observed that one such mutation in the Mismatch Repair protein Mlh1 contributes to the mild mutator phenotype when modeled in yeast (scmlh1-P157S). Compared to basal rates of mutation, a mild mutator phenotype may provide a greater overall benefit for parasites in Southeast Asia in terms of generating drug resistance without incurring

  18. Targets and Mechanisms Associated with Protection from Severe Plasmodium falciparum Malaria in Kenyan Children.

    PubMed

    Murungi, Linda M; Sondén, Klara; Llewellyn, David; Rono, Josea; Guleid, Fatuma; Williams, Andrew R; Ogada, Edna; Thairu, Amos; Färnert, Anna; Marsh, Kevin; Draper, Simon J; Osier, Faith H A

    2016-04-01

    Severe malaria (SM) is a life-threatening complication of infection with Plasmodium falciparum Epidemiological observations have long indicated that immunity against SM is acquired relatively rapidly, but prospective studies to investigate its immunological basis are logistically challenging and have rarely been undertaken. We investigated the merozoite targets and antibody-mediated mechanisms associated with protection against SM in Kenyan children aged 0 to 2 years. We designed a unique prospective matched case-control study of well-characterized SM clinical phenotypes nested within a longitudinal birth cohort of children (n= 5,949) monitored over the first 2 years of life. We quantified immunological parameters in sera collected before the SM event in cases and their individually matched controls to evaluate the prospective odds of developing SM in the first 2 years of life. Anti-AMA1 antibodies were associated with a significant reduction in the odds of developing SM (odds ratio [OR] = 0.37; 95% confidence interval [CI] = 0.15 to 0.90; P= 0.029) after adjustment for responses to all other merozoite antigens tested, while those against MSP-2, MSP-3, Plasmodium falciparum Rh2 [PfRh2], MSP-119, and the infected red blood cell surface antigens were not. The combined ability of total IgG to inhibit parasite growth and mediate the release of reactive oxygen species from neutrophils was associated with a marked reduction in the odds of developing SM (OR = 0.07; 95% CI = 0.006 to 0.82;P= 0.03). Assays of these two functional mechanisms were poorly correlated (Spearman rank correlation coefficient [rs] = 0.12;P= 0.07). Our data provide epidemiological evidence that multiple antibody-dependent mechanisms contribute to protective immunity via distinct targets whose identification could accelerate the development of vaccines to protect against SM. PMID:26787721

  19. Evidence of a Mild Mutator Phenotype in Cambodian Plasmodium falciparum Malaria Parasites.

    PubMed

    Lee, Andrew H; Fidock, David A

    2016-01-01

    Malaria control efforts have been continuously stymied by drug-resistant strains of Plasmodium falciparum, which typically originate in Southeast Asia prior to spreading into high-transmission settings in Africa. One earlier proposed explanation for Southeast Asia being a hotbed of resistance has been the hypermutability or "Accelerated Resistance to Multiple Drugs" (ARMD) phenotype, whereby multidrug-resistant Southeast Asian parasites were reported to exhibit 1,000-fold higher rates of resistance to unrelated antimalarial agents when compared to drug-sensitive parasites. However, three recent studies do not recapitulate this hypermutability phenotype. Intriguingly, genome sequencing of recently derived multidrug-resistant Cambodian isolates has identified a high proportion of DNA repair gene mutations in multidrug-resistant parasites, suggesting their potential role in shaping local parasite evolution. By adapting fluctuation assays for use in P. falciparum, we have examined the in vitro mutation rates of five recent Cambodian isolates and three reference laboratory strains. For these studies we also generated a knockout parasite line lacking the DNA repair factor Exonuclease I. In these assays, parasites were typed for their ability to acquire resistance to KAE609, currently in advanced clinical trials, yielding 13 novel mutations in the Na+/H+-ATPase PfATP4, the primary resistance determinant. We observed no evidence of hypermutability. Instead, we found evidence of a mild mutator (up to a 3.4-fold increase in mutation rate) phenotype in two artemisinin-resistant Cambodian isolates, which carry DNA repair gene mutations. We observed that one such mutation in the Mismatch Repair protein Mlh1 contributes to the mild mutator phenotype when modeled in yeast (scmlh1-P157S). Compared to basal rates of mutation, a mild mutator phenotype may provide a greater overall benefit for parasites in Southeast Asia in terms of generating drug resistance without incurring

  20. Evidence of a Mild Mutator Phenotype in Cambodian Plasmodium falciparum Malaria Parasites

    PubMed Central

    Lee, Andrew H.; Fidock, David A.

    2016-01-01

    Malaria control efforts have been continuously stymied by drug-resistant strains of Plasmodium falciparum, which typically originate in Southeast Asia prior to spreading into high-transmission settings in Africa. One earlier proposed explanation for Southeast Asia being a hotbed of resistance has been the hypermutability or “Accelerated Resistance to Multiple Drugs” (ARMD) phenotype, whereby multidrug-resistant Southeast Asian parasites were reported to exhibit 1,000-fold higher rates of resistance to unrelated antimalarial agents when compared to drug-sensitive parasites. However, three recent studies do not recapitulate this hypermutability phenotype. Intriguingly, genome sequencing of recently derived multidrug-resistant Cambodian isolates has identified a high proportion of DNA repair gene mutations in multidrug-resistant parasites, suggesting their potential role in shaping local parasite evolution. By adapting fluctuation assays for use in P. falciparum, we have examined the in vitro mutation rates of five recent Cambodian isolates and three reference laboratory strains. For these studies we also generated a knockout parasite line lacking the DNA repair factor Exonuclease I. In these assays, parasites were typed for their ability to acquire resistance to KAE609, currently in advanced clinical trials, yielding 13 novel mutations in the Na+/H+-ATPase PfATP4, the primary resistance determinant. We observed no evidence of hypermutability. Instead, we found evidence of a mild mutator (up to a 3.4-fold increase in mutation rate) phenotype in two artemisinin-resistant Cambodian isolates, which carry DNA repair gene mutations. We observed that one such mutation in the Mismatch Repair protein Mlh1 contributes to the mild mutator phenotype when modeled in yeast (scmlh1-P157S). Compared to basal rates of mutation, a mild mutator phenotype may provide a greater overall benefit for parasites in Southeast Asia in terms of generating drug resistance without incurring

  1. Selective Killing of the Human Malaria Parasite Plasmodium falciparum by a Benzylthiazolium dye

    PubMed Central

    Kelly, Jane X.; Winter, Rolf W.; Braun, Theodore P.; Osei-Agyemang, Myralyn; Hinrichs, David J.; Riscoe, Michael K.

    2007-01-01

    Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium. The most virulent form of the disease is caused by P. falciparum which infects hundreds of millions of people and is responsible for the deaths of 1 to 2 million individuals each year. An essential part of the parasitic process is the remodeling of the red blood cell membrane and its protein constituents to permit a higher flux of nutrients and waste products into or away from the intracellular parasite. Much of this increased permeability is due to a single type of broad specificity channel variously called the new permeation pathway (NPP), the nutrient channel, and the Plasmodial surface anion channel (PSAC). This channel is permeable to a range of low molecular weight solutes both charged and uncharged, with a strong preference for anions. Drugs such as furosemide that are known to block anion-selective channels inhibit PSAC. In this study we have investigated a dye known as benzothiocarboxypurine, BCP, which had been studied as a possible diagnostic aid given its selective uptake by P. falciparum infected red cells. We found that the dye enters parasitized red cells via the furosemide-inhibitable PSAC, forms a brightly fluorescent complex with parasite nucleic acids, and is selectively toxic to infected cells. Our study describes an antimalarial agent that exploits the altered permeability of Plasmodium-infected red cells as a means to killing the parasite and highlights a chemical reagent that may prove useful in high throughput screening of compounds for inhibitors of the channel. PMID:17266952

  2. Targets and Mechanisms Associated with Protection from Severe Plasmodium falciparum Malaria in Kenyan Children

    PubMed Central

    Sondén, Klara; Llewellyn, David; Rono, Josea; Guleid, Fatuma; Williams, Andrew R.; Ogada, Edna; Thairu, Amos; Färnert, Anna; Marsh, Kevin; Draper, Simon J.; Osier, Faith H. A.

    2016-01-01

    Severe malaria (SM) is a life-threatening complication of infection with Plasmodium falciparum. Epidemiological observations have long indicated that immunity against SM is acquired relatively rapidly, but prospective studies to investigate its immunological basis are logistically challenging and have rarely been undertaken. We investigated the merozoite targets and antibody-mediated mechanisms associated with protection against SM in Kenyan children aged 0 to 2 years. We designed a unique prospective matched case-control study of well-characterized SM clinical phenotypes nested within a longitudinal birth cohort of children (n = 5,949) monitored over the first 2 years of life. We quantified immunological parameters in sera collected before the SM event in cases and their individually matched controls to evaluate the prospective odds of developing SM in the first 2 years of life. Anti-AMA1 antibodies were associated with a significant reduction in the odds of developing SM (odds ratio [OR] = 0.37; 95% confidence interval [CI] = 0.15 to 0.90; P = 0.029) after adjustment for responses to all other merozoite antigens tested, while those against MSP-2, MSP-3, Plasmodium falciparum Rh2 [PfRh2], MSP-119, and the infected red blood cell surface antigens were not. The combined ability of total IgG to inhibit parasite growth and mediate the release of reactive oxygen species from neutrophils was associated with a marked reduction in the odds of developing SM (OR = 0.07; 95% CI = 0.006 to 0.82; P = 0.03). Assays of these two functional mechanisms were poorly correlated (Spearman rank correlation coefficient [rs] = 0.12; P = 0.07). Our data provide epidemiological evidence that multiple antibody-dependent mechanisms contribute to protective immunity via distinct targets whose identification could accelerate the development of vaccines to protect against SM. PMID:26787721

  3. Protective epitopes of the Plasmodium falciparum SERA5 malaria vaccine reside in intrinsically unstructured N-terminal repetitive sequences.

    PubMed

    Yagi, Masanori; Bang, Gilles; Tougan, Takahiro; Palacpac, Nirianne M Q; Arisue, Nobuko; Aoshi, Taiki; Matsumoto, Yoshitsugu; Ishii, Ken J; Egwang, Thomas G; Druilhe, Pierre; Horii, Toshihiro

    2014-01-01

    The malaria vaccine candidate antigen, SE36, is based on the N-terminal 47 kDa domain of Plasmodium falciparum serine repeat antigen 5 (SERA5). In epidemiological studies, we have previously shown the inhibitory effects of SE36 specific antibodies on in vitro parasite growth and the negative correlation between antibody level and malaria symptoms. A phase 1 b trial of the BK-SE36 vaccine in Uganda elicited 72% protective efficacy against symptomatic malaria in children aged 6-20 years during the follow-up period 130-365 days post-second vaccination. Here, we performed epitope mapping with synthetic peptides covering the whole sequence of SE36 to identify and map dominant epitopes in Ugandan adult serum presumed to have clinical immunity to P. falciparum malaria. High titer sera from the Ugandan adults predominantly reacted with peptides corresponding to two successive N-terminal regions of SERA5 containing octamer repeats and serine rich sequences, regions of SERA5 that were previously reported to have limited polymorphism. Affinity purified antibodies specifically recognizing the octamer repeats and serine rich sequences exhibited a high antibody-dependent cellular inhibition (ADCI) activity that inhibited parasite growth. Furthermore, protein structure predictions and structural analysis of SE36 using spectroscopic methods indicated that N-terminal regions possessing inhibitory epitopes are intrinsically unstructured. Collectively, these results suggest that strict tertiary structure of SE36 epitopes is not required to elicit protective antibodies in naturally immune Ugandan adults. PMID:24886718

  4. Protective Epitopes of the Plasmodium falciparum SERA5 Malaria Vaccine Reside in Intrinsically Unstructured N-Terminal Repetitive Sequences

    PubMed Central

    Tougan, Takahiro; Palacpac, Nirianne M. Q.; Arisue, Nobuko; Aoshi, Taiki; Matsumoto, Yoshitsugu; Ishii, Ken J.; Egwang, Thomas G.; Druilhe, Pierre; Horii, Toshihiro

    2014-01-01

    The malaria vaccine candidate antigen, SE36, is based on the N-terminal 47 kDa domain of Plasmodium falciparum serine repeat antigen 5 (SERA5). In epidemiological studies, we have previously shown the inhibitory effects of SE36 specific antibodies on in vitro parasite growth and the negative correlation between antibody level and malaria symptoms. A phase 1 b trial of the BK-SE36 vaccine in Uganda elicited 72% protective efficacy against symptomatic malaria in children aged 6–20 years during the follow-up period 130–365 days post–second vaccination. Here, we performed epitope mapping with synthetic peptides covering the whole sequence of SE36 to identify and map dominant epitopes in Ugandan adult serum presumed to have clinical immunity to P. falciparum malaria. High titer sera from the Ugandan adults predominantly reacted with peptides corresponding to two successive N-terminal regions of SERA5 containing octamer repeats and serine rich sequences, regions of SERA5 that were previously reported to have limited polymorphism. Affinity purified antibodies specifically recognizing the octamer repeats and serine rich sequences exhibited a high antibody-dependent cellular inhibition (ADCI) activity that inhibited parasite growth. Furthermore, protein structure predictions and structural analysis of SE36 using spectroscopic methods indicated that N-terminal regions possessing inhibitory epitopes are intrinsically unstructured. Collectively, these results suggest that strict tertiary structure of SE36 epitopes is not required to elicit protective antibodies in naturally immune Ugandan adults. PMID:24886718

  5. Progress with Plasmodium falciparum sporozoite (PfSPZ)-based malaria vaccines.

    PubMed

    Richie, Thomas L; Billingsley, Peter F; Sim, B Kim Lee; James, Eric R; Chakravarty, Sumana; Epstein, Judith E; Lyke, Kirsten E; Mordmüller, Benjamin; Alonso, Pedro; Duffy, Patrick E; Doumbo, Ogobara K; Sauerwein, Robert W; Tanner, Marcel; Abdulla, Salim; Kremsner, Peter G; Seder, Robert A; Hoffman, Stephen L

    2015-12-22

    Sanaria Inc. has developed methods to manufacture, purify and cryopreserve aseptic Plasmodium falciparum (Pf) sporozoites (SPZ), and is using this platform technology to develop an injectable PfSPZ-based vaccine that provides high-grade, durable protection against infection with Pf malaria. Several candidate vaccines are being developed and tested, including PfSPZ Vaccine, in which the PfSPZ are attenuated by irradiation, PfSPZ-CVac, in which fully infectious PfSPZ are attenuated in vivo by concomitant administration of an anti-malarial drug, and PfSPZ-GA1, in which the PfSPZ are attenuated by gene knockout. Forty-three research groups in 15 countries, organized as the International PfSPZ Consortium (I-PfSPZ-C), are collaborating to advance this program by providing intellectual, clinical, and financial support. Fourteen clinical trials of these products have been completed in the USA, Europe and Africa, two are underway and at least 12 more are planned for 2015-2016 in the US (four trials), Germany (2 trials), Tanzania, Kenya, Mali, Burkina Faso, Ghana and Equatorial Guinea. Sanaria anticipates application to license a first generation product as early as late 2017, initially to protect adults, and a year later to protect all persons >6 months of age for at least six months. Improved vaccine candidates will be advanced as needed until the following requirements have been met: long-term protection against natural transmission, excellent safety and tolerability, and operational feasibility for population-wide administration. Here we describe the three most developed whole PfSPZ vaccine candidates, associated clinical trials, initial plans for licensure and deployment, and long-term objectives for a final product suitable for mass administration to achieve regional malaria elimination and eventual global eradication.

  6. Splenic retention of Plasmodium falciparum gametocytes to block the transmission of malaria.

    PubMed

    Duez, Julien; Holleran, John P; Ndour, Papa Alioune; Loganathan, Sasdekumar; Amireault, Pascal; Français, Olivier; El Nemer, Wassim; Le Pioufle, Bruno; Amado, Inês F; Garcia, Sylvie; Chartrel, Nathalie; Le Van Kim, Caroline; Lavazec, Catherine; Avery, Vicky M; Buffet, Pierre A

    2015-07-01

    Plasmodium falciparum is transmitted from humans to Anopheles mosquito vectors via the sexual erythrocytic forms termed gametocytes. Erythrocyte filtration through microsphere layers (microsphiltration) had shown that circulating gametocytes are deformable. Compounds reducing gametocyte deformability would induce their splenic clearance, thus removing them from the blood circulation and blocking malaria transmission. The hand-made, single-sample prototype for microsphiltration was miniaturized to a 96-well microtiter plate format, and gametocyte retention in the microsphere filters was quantified by high-content imaging. The stiffening activity of 40 pharmacological compounds was assessed in microtiter plates, using a small molecule (calyculin) as a positive control. The stiffening activity of calyculin was assessed in spleen-mimetic microfluidic chips and in macrophage-depleted mice. Marked mechanical retention (80% to 90%) of mature gametocytes was obtained in microplates following exposure to calyculin at concentrations with no effect on parasite viability. Of the 40 compounds tested, including 20 antimalarials, only 5 endoperoxides significantly increased gametocyte retention (1.5- to 2.5-fold; 24 h of exposure at 1 μM). Mature gametocytes exposed to calyculin accumulated in microfluidic chips and were cleared from the circulation of macrophage-depleted mice as rapidly as heat-stiffened erythrocytes, thus confirming results obtained using the microsphiltration assay. An automated miniaturized approach to select compounds for their gametocyte-stiffening effect has been established. Stiffening induces gametocyte clearance both in vitro and in vivo. Based on physiologically validated tools, this screening cascade can identify novel compounds and uncover new targets to block malaria transmission. Innovative applications in hematology are also envisioned. PMID:25941228

  7. Splenic Retention of Plasmodium falciparum Gametocytes To Block the Transmission of Malaria

    PubMed Central

    Duez, Julien; Holleran, John P.; Ndour, Papa Alioune; Loganathan, Sasdekumar; Amireault, Pascal; Français, Olivier; El Nemer, Wassim; Le Pioufle, Bruno; Amado, Inês F.; Garcia, Sylvie; Chartrel, Nathalie; Le Van Kim, Caroline; Lavazec, Catherine; Avery, Vicky M.

    2015-01-01

    Plasmodium falciparum is transmitted from humans to Anopheles mosquito vectors via the sexual erythrocytic forms termed gametocytes. Erythrocyte filtration through microsphere layers (microsphiltration) had shown that circulating gametocytes are deformable. Compounds reducing gametocyte deformability would induce their splenic clearance, thus removing them from the blood circulation and blocking malaria transmission. The hand-made, single-sample prototype for microsphiltration was miniaturized to a 96-well microtiter plate format, and gametocyte retention in the microsphere filters was quantified by high-content imaging. The stiffening activity of 40 pharmacological compounds was assessed in microtiter plates, using a small molecule (calyculin) as a positive control. The stiffening activity of calyculin was assessed in spleen-mimetic microfluidic chips and in macrophage-depleted mice. Marked mechanical retention (80% to 90%) of mature gametocytes was obtained in microplates following exposure to calyculin at concentrations with no effect on parasite viability. Of the 40 compounds tested, including 20 antimalarials, only 5 endoperoxides significantly increased gametocyte retention (1.5- to 2.5-fold; 24 h of exposure at 1 μM). Mature gametocytes exposed to calyculin accumulated in microfluidic chips and were cleared from the circulation of macrophage-depleted mice as rapidly as heat-stiffened erythrocytes, thus confirming results obtained using the microsphiltration assay. An automated miniaturized approach to select compounds for their gametocyte-stiffening effect has been established. Stiffening induces gametocyte clearance both in vitro and in vivo. Based on physiologically validated tools, this screening cascade can identify novel compounds and uncover new targets to block malaria transmission. Innovative applications in hematology are also envisioned. PMID:25941228

  8. Splenic retention of Plasmodium falciparum gametocytes to block the transmission of malaria.

    PubMed

    Duez, Julien; Holleran, John P; Ndour, Papa Alioune; Loganathan, Sasdekumar; Amireault, Pascal; Français, Olivier; El Nemer, Wassim; Le Pioufle, Bruno; Amado, Inês F; Garcia, Sylvie; Chartrel, Nathalie; Le Van Kim, Caroline; Lavazec, Catherine; Avery, Vicky M; Buffet, Pierre A

    2015-07-01

    Plasmodium falciparum is transmitted from humans to Anopheles mosquito vectors via the sexual erythrocytic forms termed gametocytes. Erythrocyte filtration through microsphere layers (microsphiltration) had shown that circulating gametocytes are deformable. Compounds reducing gametocyte deformability would induce their splenic clearance, thus removing them from the blood circulation and blocking malaria transmission. The hand-made, single-sample prototype for microsphiltration was miniaturized to a 96-well microtiter plate format, and gametocyte retention in the microsphere filters was quantified by high-content imaging. The stiffening activity of 40 pharmacological compounds was assessed in microtiter plates, using a small molecule (calyculin) as a positive control. The stiffening activity of calyculin was assessed in spleen-mimetic microfluidic chips and in macrophage-depleted mice. Marked mechanical retention (80% to 90%) of mature gametocytes was obtained in microplates following exposure to calyculin at concentrations with no effect on parasite viability. Of the 40 compounds tested, including 20 antimalarials, only 5 endoperoxides significantly increased gametocyte retention (1.5- to 2.5-fold; 24 h of exposure at 1 μM). Mature gametocytes exposed to calyculin accumulated in microfluidic chips and were cleared from the circulation of macrophage-depleted mice as rapidly as heat-stiffened erythrocytes, thus confirming results obtained using the microsphiltration assay. An automated miniaturized approach to select compounds for their gametocyte-stiffening effect has been established. Stiffening induces gametocyte clearance both in vitro and in vivo. Based on physiologically validated tools, this screening cascade can identify novel compounds and uncover new targets to block malaria transmission. Innovative applications in hematology are also envisioned.

  9. Progress with Plasmodium falciparum sporozoite (PfSPZ)-based malaria vaccines

    PubMed Central

    Richie, Thomas L.; Billingsley, Peter F.; Sim, B. Kim Lee; James, Eric R.; Chakravarty, Sumana; Epstein, Judith E.; Lyke, Kirsten E.; Mordmüller, Benjamin; Alonso, Pedro; Duffy, Patrick E.; Doumbo, Ogobara K.; Sauerwein, Robert W.; Tanner, Marcel; Abdulla, Salim; Kremsner, Peter G.; Seder, Robert A.; Hoffman, Stephen L.

    2016-01-01

    Sanaria Inc. has developed methods to manufacture, purify and cryopreserve aseptic Plasmodium falciparum (Pf) sporozoites (SPZ), and is using this platform technology to develop an injectable PfSPZ-based vaccine that provides high-grade, durable protection against infection with Pf malaria. Several candidate vaccines are being developed and tested, including PfSPZ Vaccine, in which the PfSPZ are attenuated by irradiation, PfSPZ-CVac, in which fully infectious PfSPZ are attenuated in vivo by concomitant administration of an anti-malarial drug, and PfSPZ-GA1, in which the PfSPZ are attenuated by gene knockout. Forty-three research groups in 15 countries, organized as the International PfSPZ Consortium (I-PfSPZ-C), are collaborating to advance this program by providing intellectual, clinical, and financial support. Fourteen clinical trials of these products have been completed in the USA, Europe and Africa, two are underway and at least 12 more are planned for 2015–2016 in the US (four trials), Germany (2 trials), Tanzania, Kenya, Mali, Burkina Faso, Ghana and Equatorial Guinea. Sanaria anticipates application to license a first generation product as early as late 2017, initially to protect adults, and a year later to protect all persons >6 months of age for at least six months. Improved vaccine candidates will be advanced as needed until the following requirements have been met: long-term protection against natural transmission, excellent safety and tolerability, and operational feasibility for population-wide administration. Here we describe the three most developed whole PfSPZ vaccine candidates, associated clinical trials, initial plans for licensure and deployment, and long-term objectives for a final product suitable for mass administration to achieve regional malaria elimination and eventual global eradication. PMID:26469720

  10. Naturally Acquired Antibody Responses to Plasmodium vivax and Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) C-Terminal 19 kDa Domains in an Area of Unstable Malaria Transmission in Southeast Asia

    PubMed Central

    Wang, Qinghui; Zhao, Zhenjun; Zhang, Xuexing; Li, Xuelian; Zhu, Min; Li, Peipei; Yang, Zhaoqing; Wang, Ying; Yan, Guiyun; Shang, Hong; Cao, Yaming; Fan, Qi; Cui, Liwang

    2016-01-01

    Understanding naturally acquired immunity to infections caused by Plasmodia in different malaria endemicity settings is needed for better vaccine designs and for exploring antibody responses as a proxy marker of malaria transmission intensity. This study investigated the sero-epidemiology of malaria along the international border between China and Myanmar, where malaria elimination action plans are in place. This study recruited 233 P. vivax and 156 P. falciparum infected subjects with acute malaria at the malaria clinics and hospitals. In addition, 93 and 67 healthy individuals from the same endemic region or from non-endemic region, respectively, were used as controls. Acute malaria infections were identified by microscopy. Anti-recombinant PfMSP119 and PvMSP119 antibody levels were measured by ELISA. Antibody responses to respective MSP119 were detected in 50.9% and 78.2% patients with acute P. vivax and P. falciparum infections, respectively. There were cross-reacting antibodies in Plasmodium patients against these two recombinant proteins, though we could not exclude the possibility of submicroscopic mixed-species infections. IgG1, IgG3 and IgG4 were the major subclasses. Interestingly, 43.2% of the healthy endemic population also had antibodies against PfMSP119, whereas only 3.9% of this population had antibodies against PvMSP119. Higher antibody levels were correlated with age and parasite density, but not with season, gender or malaria history. Both total IgG and individual IgG subclasses underwent substantial declines during the convalescent period in three months. This study demonstrated that individuals in a hypoendemic area with coexistence of P. vivax and P. falciparum can mount rapid antibody responses against both PfMSP119 and PvMSP119. The significantly higher proportion of responders to PfMSP119 in the healthy endemic population indicates higher prevalence of P. falciparum in the recent past. Specific antibodies against PvMSP119 could serve as a

  11. Evaluation of the Sensitivity of a pLDH-Based and an Aldolase-Based Rapid Diagnostic Test for Diagnosis of Uncomplicated and Severe Malaria Caused by PCR-Confirmed Plasmodium knowlesi, Plasmodium falciparum, and Plasmodium vivax

    PubMed Central

    William, Timothy; Grigg, Matthew J.; Piera, Kim; Yeo, Tsin W.; Anstey, Nicholas M.

    2013-01-01

    Plasmodium knowlesi can cause severe and fatal human malaria in Southeast Asia. Rapid diagnosis of all Plasmodium species is essential for initiation of effective treatment. Rapid diagnostic tests (RDTs) are sensitive for detection of uncomplicated and severe falciparum malaria but have not been systematically evaluated in knowlesi malaria. At a tertiary referral hospital in Sabah, Malaysia, we prospectively evaluated the sensitivity of two combination RDTs for the diagnosis of uncomplicated and severe malaria from all three potentially fatal Plasmodium species, using a pan-Plasmodium lactate dehydrogenase (pLDH)-P. falciparum histidine-rich protein 2 (PfHRP2) RDT (First Response) and a pan-Plasmodium aldolase-PfHRP2 RDT (ParaHIT). Among 293 hospitalized adults with PCR-confirmed Plasmodium monoinfection, the sensitivity of the pLDH component of the pLDH-PfHRP2 RDT was 74% (95/129; 95% confidence interval [CI], 65 to 80%), 91% (110/121; 95% CI, 84 to 95%), and 95% (41/43; 95% CI, 85 to 99%) for PCR-confirmed P. knowlesi, P. falciparum, and P. vivax infections, respectively, and 88% (30/34; 95% CI, 73 to 95%), 90% (38/42; 95% CI, 78 to 96%), and 100% (12/12; 95% CI, 76 to 100%) among patients tested before antimalarial treatment was begun. Sensitivity in severe malaria was 95% (36/38; 95% CI, 83 to 99), 100% (13/13; 95% CI, 77 to 100), and 100% (7/7; 95% CI, 65 to 100%), respectively. The aldolase component of the aldolase-PfHRP2 RDT performed poorly in all Plasmodium species. The pLDH-based RDT was highly sensitive for the diagnosis of severe malaria from all species; however, neither the pLDH- nor aldolase-based RDT demonstrated sufficiently high overall sensitivity for P. knowlesi. More sensitive RDTs are needed in regions of P. knowlesi endemicity. PMID:23345297

  12. Evaluation of the sensitivity of a pLDH-based and an aldolase-based rapid diagnostic test for diagnosis of uncomplicated and severe malaria caused by PCR-confirmed Plasmodium knowlesi, Plasmodium falciparum, and Plasmodium vivax.

    PubMed

    Barber, Bridget E; William, Timothy; Grigg, Matthew J; Piera, Kim; Yeo, Tsin W; Anstey, Nicholas M

    2013-04-01

    Plasmodium knowlesi can cause severe and fatal human malaria in Southeast Asia. Rapid diagnosis of all Plasmodium species is essential for initiation of effective treatment. Rapid diagnostic tests (RDTs) are sensitive for detection of uncomplicated and severe falciparum malaria but have not been systematically evaluated in knowlesi malaria. At a tertiary referral hospital in Sabah, Malaysia, we prospectively evaluated the sensitivity of two combination RDTs for the diagnosis of uncomplicated and severe malaria from all three potentially fatal Plasmodium species, using a pan-Plasmodium lactate dehydrogenase (pLDH)-P. falciparum histidine-rich protein 2 (PfHRP2) RDT (First Response) and a pan-Plasmodium aldolase-PfHRP2 RDT (ParaHIT). Among 293 hospitalized adults with PCR-confirmed Plasmodium monoinfection, the sensitivity of the pLDH component of the pLDH-PfHRP2 RDT was 74% (95/129; 95% confidence interval [CI], 65 to 80%), 91% (110/121; 95% CI, 84 to 95%), and 95% (41/43; 95% CI, 85 to 99%) for PCR-confirmed P. knowlesi, P. falciparum, and P. vivax infections, respectively, and 88% (30/34; 95% CI, 73 to 95%), 90% (38/42; 95% CI, 78 to 96%), and 100% (12/12; 95% CI, 76 to 100%) among patients tested before antimalarial treatment was begun. Sensitivity in severe malaria was 95% (36/38; 95% CI, 83 to 99), 100% (13/13; 95% CI, 77 to 100), and 100% (7/7; 95% CI, 65 to 100%), respectively. The aldolase component of the aldolase-PfHRP2 RDT performed poorly in all Plasmodium species. The pLDH-based RDT was highly sensitive for the diagnosis of severe malaria from all species; however, neither the pLDH- nor aldolase-based RDT demonstrated sufficiently high overall sensitivity for P. knowlesi. More sensitive RDTs are needed in regions of P. knowlesi endemicity.

  13. [Multiple and successive treatment failures in a patient infected by Plasmodium falciparum in Cambodia and treated by dihydroartemisinin-piperaquine].

    PubMed

    Witkowski, B; Khim, N; Kim, S; Domergue, A; Duru, V; Menard, D

    2016-05-01

    Cases of treatment failures following administration of artemisinin-based combination therapies (ACT) remain rare in malaria endemic areas. In Cambodia, however, failures of these treatments are now commonly observed. Usually, these post-treatment recurrences occur only once and a second course of the same treatment is sufficient to cure patients.We describe here an atypical case of a Plasmodium falciparum-infected patient manifesting several malaria recrudescence episodes following dihydroartemisinin-piperaquine (Eurartesim®) treatment. This case report illustrates the current issue of resistance to the latest generation of antimalarial drugs in Southeast Asia and highlights the difficulty in efficaciously fighting malaria in this region if new therapy remains unimplemented. PMID:27100863

  14. Falciparum malaria in eastern Thailand: a randomized trial of the efficacy of a single dose of mefloquine.

    PubMed Central

    Fontanet, A. L.; Johnston, B. D.; Walker, A. M.; Bergqvist, Y.; Hellgren, U.; Rooney, W.

    1994-01-01

    Reported are the results of a randomized trial of a single dose of mefloquine (15 mg/kg or 25 mg/kg body weight) for the treatment of uncomplicated multidrug-resistant falciparum malaria. Of the 110 adult patients enrolled in the study 57 were randomly assigned to the 15 mg/kg group and 53 to the 25 mg/kg group. The baseline characteristics of the patients did not differ significantly in the two groups, except that those in the 15 mg/kg group had lower haemoglobin levels. Adverse effects following treatment were commoner in the 25 mg/kg group, but not significantly so. Seven patients (6%) did not complete the 42-day follow-up. The parasitological failure rates in the 15 and 25 mg/kg groups were, respectively, 50% (28/56) and 43% (25/53) on day 28, and 62% (33/53) and 56% (28/50) on day 42. Treatment failures were not correlated with the serum mefloquine concentrations on day 2, and 13 out of 19 patients with serum mefloquine concentrations > 2000 micrograms/l on day 2 showed an R response during the follow-up. The mean ratio between the concentrations of the (SR)-(-) and (RS)-(+) enantiomers of mefloquine on day 2 was 3.37, indicating that there are differences in their pharmacokinetics. Re-treatment of patients who showed an R response with seven days of quinine (30 mg.kg-1.day-1)+tetracycline (25 mg.kg-1.day-1) was successful in 93% of the cases. PMID:8131253

  15. Therapeutic Efficacy of Artemether-Lumefantrine (Coartem®) in Treating Uncomplicated P. falciparum Malaria in Metehara, Eastern Ethiopia: Regulatory Clinical Study

    PubMed Central

    Assefa, Ashenafi; Mohamed, Hussein; Solomon, Hiwot; Woyessa, Adugna; Assefa, Yibeltal; Kebede, Amha; Kassa, Moges

    2016-01-01

    Background As per the WHO recommendation, the development of resistance by P. falciparum to most artemisinin combination therapies (ACTs) triggered the need for routine monitoring of the efficacy of the drugs every two years in all malaria endemic countries. Hence, this study was carried out to assess the therapeutic efficacy of Artemether-Lumefantrine (Coartem®) in treating the uncomplicated falciparum malaria, after 9 years of its introduction in the Metehara, Eastern Ethiopia. Method This is part of the therapeutic efficacy studies by the Federal Ministry of Health Ethiopia, which were conducted in regionally representative sentinel sites in the country from October 2014 to January 2015. Based on the study criteria set by WHO, febrile and malaria suspected outpatients in the health center were consecutively recruited to study. A standard six-dose regimen of AL was administered over three days and followed up for measuring therapeutic responses over 28 days. Data entry and analysis was done by using the WHO designed Excel spreadsheet and SPSS version 20 for Windows. Statistical significant was considered for P-value less than 0.05. Result Of the 91 patients enrolled, the day-28 analysis showed 83 adequate clinical and parasitological responses (ACPRs). Per protocol analysis, PCR-uncorrected & corrected cure rates of Coartem® among the study participants were 97.6% (95%CI: 93.6–99.5) and 98.8% (CI: 93.5–100%), respectively. No parasite detected on day 3 and onwards. Fever clearance was above 91% on day-3. Mean hemoglobin was significantly increased (P<0.000) from 12.39 g/dl at day 0 to 13.45 g/dl on day 28. No serious adverse drug reactions were observed among the study participants. Conclusion This study showed high efficacy of AL in the study area, which suggests the continuation of AL as first line drug for the treatment of uncomplicated P. falciparum malaria in the study area. This study recommends further studies on drug toxicity, particularly on

  16. Quinine-induced arrhythmia in a patient with severe malaria.

    PubMed

    Gunawan, Carta A; Harijanto, Paul N; Nugroho, Agung

    2007-01-01

    It was reported that there was a case of severe malaria patient with jaundice who presented with arrhythmia (premature ventricular contraction) while getting quinine infusion was reported. A man, 25 years old, was admitted to hospital with high fever, chill, vomiting, jaundice. The patient was fully conscious, blood pressure 120/80 mmHg, pulse rate 100 x/minute, regular. On admission, laboratory examination showed Plasmodium falciparum (++++), total bilirubin 8.25 mg/dL, conjugated bilirubin 4.36 mg/dL, unconjugated bilirubin 3.89 mg/dL, potassium 3.52 meq/L Patient was diagnosed as severe malaria with jaundice and got quinine infusion in dextrose 5% 500 mg/8 hour. On the second day the patient had vomitus, diarrhea, tinnitus, loss of hearing. After 30 hours of quinine infusion the patient felt palpitation and electrocardiography (ECG) recording showed premature ventricular contraction (PVC) > 5 x/minute, trigemini, constant type--sinoatrial block, positive U wave. He was treated with lidocaine 50 mg intravenously followed by infusion 1500 mg in dextrose 5%/24 hour and potassium aspartate tablet. Quinine infusion was discontinued and changed with sulfate quinine tablets. Three hours later the patient felt better, the frequency of PVC reduced to 4 - 5 x/minute and on the third day ECG was normal, potassium level was 3.34 meq/L. He was discharged on 7th day in good condition. Quinine, like quinidine, is a chincona alkaloid that has anti-arrhythmic property, although it also pro-arrhythmic that can cause various arrhythmias, including severe arrhythmia such as multiple PVC. Administration of parenteral quinine must be done carefully and with good observation because of its pro-arrhythmic effect, especially in older patients who have heart diseases or patients with electrolyte disorder (hypokalemia) which frequently occurs due to vomiting and or diarrhea in malaria cases. PMID:17297207

  17. Antisense long noncoding RNAs regulate var gene activation in the malaria parasite Plasmodium falciparum.

    PubMed

    Amit-Avraham, Inbar; Pozner, Guy; Eshar, Shiri; Fastman, Yair; Kolevzon, Netanel; Yavin, Eylon; Dzikowski, Ron

    2015-03-01

    The virulence of Plasmodium falciparum, the causative agent of the deadliest form of human malaria, is attributed to its ability to evade human immunity through antigenic variation. These parasites alternate between expression of variable antigens, encoded by members of a multicopy gene family named var. Immune evasion through antigenic variation depends on tight regulation of var gene expression, ensuring that only a single var gene is expressed at a time while the rest of the family is maintained transcriptionally silent. Understanding how a single gene is chosen for activation is critical for understanding mutually exclusive expression but remains a mystery. Here, we show that antisense long noncoding RNAs (lncRNAs) initiating from var introns are associated with the single active var gene at the time in the cell cycle when the single var upstream promoter is active. We demonstrate that these antisense transcripts are incorporated into chromatin, and that expression of these antisense lncRNAs in trans triggers activation of a silent var gene in a sequence- and dose-dependent manner. On the other hand, interference with these lncRNAs using complement peptide nucleic acid molecules down-regulated the active var gene, erased the epigenetic memory, and induced expression switching. Altogether, our data provide evidence that these antisense lncRNAs play a key role in regulating var gene activation and mutually exclusive expression.

  18. Crystallization and preliminary crystallographic analysis of orotidine 5′-monophosphate decarboxylase from the human malaria parasite Plasmodium falciparum

    SciTech Connect

    Krungkrai, Sudaratana R.; Tokuoka, Keiji; Kusakari, Yukiko; Inoue, Tsuyoshi; Adachi, Hiroaki; Matsumura, Hiroyoshi; Takano, Kazufumi; Murakami, Satoshi; Mori, Yusuke; Kai, Yasushi; Krungkrai, Jerapan; Horii, Toshihiro

    2006-06-01

    Orotidine 5′-monophosphate decarboxylase of human malaria parasite P. falciparum was crystallized by the seeding method in a hanging drop using PEG 3000 as a precipitant. A complete set of diffraction data from a native crystal was collected to 2.7 Å resolution at 100 K using synchrotron radiation. Orotidine 5′-monophosphate (OMP) decarboxylase (OMPDC; EC 4.1.1.23) catalyzes the final step in the de novo synthesis of uridine 5′-monophosphate (UMP) and defects in the enzyme are lethal in the malaria parasite Plasmodium falciparum. Active recombinant P. falciparum OMPDC (PfOMPDC) was crystallized by the seeding method in a hanging drop using PEG 3000 as a precipitant. A complete set of diffraction data from a native crystal was collected to 2.7 Å resolution at 100 K using synchrotron radiation at the Swiss Light Source. The crystal exhibits trigonal symmetry (space group R3), with hexagonal unit-cell parameters a = b = 201.81, c = 44.03 Å. With a dimer in the asymmetric unit, the solvent content is 46% (V{sub M} = 2.3 Å{sup 3} Da{sup −1})

  19. Translocation of sickle cell erythrocyte microRNAs into Plasmodium falciparum inhibits parasite translation and contributes to malaria resistance.

    PubMed

    LaMonte, Gregory; Philip, Nisha; Reardon, Joseph; Lacsina, Joshua R; Majoros, William; Chapman, Lesley; Thornburg, Courtney D; Telen, Marilyn J; Ohler, Uwe; Nicchitta, Christopher V; Haystead, Timothy; Chi, Jen-Tsan

    2012-08-16

    Erythrocytes carrying a variant hemoglobin allele (HbS), which causes sickle cell disease and resists infection by the malaria parasite Plasmodium falciparum. The molecular basis of this resistance, which has long been recognized as multifactorial, remains incompletely understood. Here we show that the dysregulated microRNA (miRNA) composition, of either heterozygous HbAS or homozygous HbSS erythrocytes, contributes to resistance against P. falciparum. During the intraerythrocytic life cycle of P. falciparum, a subset of erythrocyte miRNAs translocate into the parasite. Two miRNAs, miR-451 and let-7i, were highly enriched in HbAS and HbSS erythrocytes, and these miRNAs, along with miR-223, negatively regulated parasite growth. Surprisingly, we found that miR-451 and let-7i integrated into essential parasite messenger RNAs and, via impaired ribosomal loading, resulted in translational inhibition. Hence, sickle cell erythrocytes exhibit cell-intrinsic resistance to malaria in part through an atypical miRNA activity, which may represent a unique host defense strategy against complex eukaryotic pathogens.

  20. A new ELISA kit which uses a combination of Plasmodium falciparum extract and recombinant Plasmodium vivax antigens as an alternative to IFAT for detection of malaria antibodies

    PubMed Central

    Doderer, Cecile; Heschung, Aurelie; Guntz, Phillippe; Cazenave, Jean-Pierre; Hansmann, Yves; Senegas, Alexandre; Pfaff, Alexander W; Abdelrahman, Tamer; Candolfi, Ermanno

    2007-01-01

    Background The methods most commonly used to measure malarial antibody titres are the Indirect Fluorescence Antibody Test (IFAT), regarded as the gold standard, and the Enzyme-Linked ImmunoSorbent Assay (ELISA). The objective here was to assess the diagnostic performance, i.e. the sensitivity and specificity, of a new malaria antibody ELISA kit in comparison to IFAT. This new ELISA kit, the ELISA malaria antibody test (DiaMed), uses a combination of crude soluble Plasmodium falciparum extract and recombinant Plasmodium vivax antigens. Methods Two groups were used: 95 samples from malaria patients to assess the clinical sensitivity and 2,152 samples from blood donors, who had not been exposed to malaria, to assess the clinical specificity. Results The DiaMed ELISA test kit had a clinical sensitivity of 84.2% and a clinical specificity of 99.6% as compared with 70.5% and 99.6% respectively, using the IFAT method. The ELISA method was more sensitive than the IFAT method for P. vivax infections (75% vs. 25%). However, in 923 malaria risk donors the analytical sensitivity of the ELISA test was 40% and its specificity 98.3%, performances impaired by large numbers of equivocal results non-concordant between ELISA and IFAT. When the overall analytical performances of ELISA was compared to IFAT, the ELISA efficiency J index was 0.84 versus 0.71 for IFAT. Overall analytical sensitivity was 93.1% and the analytical specificity 96.7%. Overall agreement between the two methods reached 0.97 with a reliability k index of 0.64. Conclusion The DiaMed ELISA test kit shows a good correlation with IFAT for analytical and clinical parameters. It may be an interesting method to replace the IFAT especially in blood banks, but further extensive investigations are needed to examine the analytical performance of the assay, especially in a blood bank setting. PMID:17313669

  1. Modelling entomological-climatic interactions of Plasmodium falciparum malaria transmission in two Colombian endemic-regions: contributions to a National Malaria Early Warning System

    PubMed Central

    Ruiz, Daniel; Poveda, Germán; Vélez, Iván D; Quiñones, Martha L; Rúa, Guillermo L; Velásquez, Luz E; Zuluaga, Juan S

    2006-01-01

    Background Malaria has recently re-emerged as a public health burden in Colombia. Although the problem seems to be climate-driven, there remain significant gaps of knowledge in the understanding of the complexity of malaria transmission, which have motivated attempts to develop a comprehensive model. Methods The mathematical tool was applied to represent Plasmodium falciparum malaria transmission in two endemic-areas. Entomological exogenous variables were estimated through field campaigns and laboratory experiments. Availability of breeding places was included towards representing fluctuations in vector densities. Diverse scenarios, sensitivity analyses and instabilities cases were considered during experimentation-validation process. Results Correlation coefficients and mean square errors between observed and modelled incidences reached 0.897–0.668 (P > 0.95) and 0.0002–0.0005, respectively. Temperature became the most relevant climatic parameter driving the final incidence. Accordingly, malaria outbreaks are possible during the favourable epochs following the onset of El Niño warm events. Sporogonic and gonotrophic cycles showed to be the entomological key-variables controlling the transmission potential of mosquitoes' population. Simulation results also showed that seasonality of vector density becomes an important factor towards understanding disease transmission. Conclusion The model constitutes a promising tool to deepen the understanding of the multiple interactions related to malaria transmission conducive to outbreaks. In the foreseeable future it could be implemented as a tool to diagnose possible dynamical patterns of malaria incidence under several scenarios, as well as a decision-making tool for the early detection and control of outbreaks. The model will be also able to be merged with forecasts of El Niño events to provide a National Malaria Early Warning System. PMID:16882349

  2. Variation in susceptibility of African Plasmodium falciparum malaria parasites to TEP1 mediated killing in Anopheles gambiae mosquitoes

    PubMed Central

    Eldering, Maarten; Morlais, Isabelle; van Gemert, Geert-Jan; van de Vegte-Bolmer, Marga; Graumans, Wouter; Siebelink-Stoter, Rianne; Vos, Martijn; Abate, Luc; Roeffen, Will; Bousema, Teun; Levashina, Elena A.; Sauerwein, Robert W.

    2016-01-01

    Anopheles gambiae s.s. mosquitoes are efficient vectors for Plasmodium falciparum, although variation exists in their susceptibility to infection. This variation depends partly on the thioester-containing protein 1 (TEP1) and TEP depletion results in significantly elevated numbers of oocysts in susceptible and resistant mosquitoes. Polymorphism in the Plasmodium gene coding for the surface protein Pfs47 modulates resistance of some parasite laboratory strains to TEP1-mediated killing. Here, we examined resistance of P. falciparum isolates of African origin (NF54, NF165 and NF166) to TEP1-mediated killing in a susceptible Ngousso and a refractory L3–5 strain of A. gambiae. All parasite clones successfully developed in susceptible mosquitoes with limited evidence for an impact of TEP1 on transmission efficiency. In contrast, NF166 and NF165 oocyst densities were strongly reduced in refractory mosquitoes and TEP1 silencing significantly increased oocyst densities. Our results reveal differences between African P. falciparum strains in their capacity to evade TEP1-mediated killing in resistant mosquitoes. There was no significant correlation between Pfs47 genotype and resistance of a given P. falciparum isolate for TEP1 killing. These data suggest that polymorphisms in this locus are not the sole mediators of immune evasion of African malaria parasites. PMID:26861587

  3. The challenge of artemisinin resistance can only be met by eliminating Plasmodium falciparum malaria across the Greater Mekong subregion.

    PubMed

    Smith Gueye, Cara; Newby, Gretchen; Hwang, Jimee; Phillips, Allison A; Whittaker, Maxine; MacArthur, John R; Gosling, Roly D; Feachem, Richard G A

    2014-01-01

    Artemisinin-based combinations are currently the most effective anti-malarials and, in addition to vector control, have led to significant declines in malaria morbidity and mortality. However, foci of artemisinin drug resistance have been identified in the Greater Mekong subregion (GMS) of the Asia Pacific, threatening the major gains made in malaria control and potentially creating a parasite pool that is more difficult to treat and eliminate. Efforts are underway to halt the spread of artemisinin resistance, including coordination of activities and funding, and identification of areas of suspected artemisinin resistance, now using a newly identified molecular marker. However, targeting resources to the containment of resistant parasites is likely inefficient and monitoring impact is challenging. A more sustainable solution is the rapid elimination of all Plasmodium falciparum parasites from the GMS. This strategy is more efficient for several reasons. First, a subregional strategy is in line with current commitment to elimination and will build upon the existing national political support for elimination as well as enhancing collaboration among countries. Second, the challenge of human mobility in the GMS is subregional in scope and requires a harmonized elimination strategy. Third, countries will need to improve and intensify malaria operations to reach elimination, and this will be a singular goal across the subregion. Rallying around the goal of P. falciparum elimination will not only utilize existing regional bodies to catalyze political and funding support, but will also leverage the funding already in place to achieve this subregional goal.

  4. A simple and predictive phenotypic High Content Imaging assay for Plasmodium falciparum mature gametocytes to identify malaria transmission blocking compounds

    PubMed Central

    Lucantoni, Leonardo; Silvestrini, Francesco; Signore, Michele; Siciliano, Giulia; Eldering, Maarten; Dechering, Koen J.; Avery, Vicky M.; Alano, Pietro

    2015-01-01

    Plasmodium falciparum gametocytes, specifically the mature stages, are the only malaria parasite stage in humans transmissible to the mosquito vector. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria and tools allowing the screening of large compound libraries with high predictive power are needed to identify new candidates. As gametocytes are not a replicative stage it is difficult to apply the same drug screening methods used for asexual stages. Here we propose an assay, based on high content imaging, combining “classic” gametocyte viability readout based on gametocyte counts with a functional viability readout, based on gametocyte activation and the discrimination of the typical gamete spherical morphology. This simple and rapid assay has been miniaturized to a 384-well format using acridine orange staining of wild type P. falciparum 3D7A sexual forms, and was validated by screening reference antimalarial drugs and the MMV Malaria Box. The assay demonstrated excellent robustness and ability to identify quality hits with high likelihood of confirmation of transmission reducing activity in subsequent mosquito membrane feeding assays. PMID:26553647

  5. Malaria vaccines: using models of immunity and functional genomics tools to accelerate the development of vaccines against Plasmodium falciparum.

    PubMed

    Duffy, Patrick E; Krzych, Urszula; Francis, Susan; Fried, Michal

    2005-03-18

    Naturally acquired immunity and immunity acquired after immunization with attenuated parasites indicate that a vaccine against malaria is feasible. Several obstacles have stymied malaria vaccine development, among them our poor understanding of protective immunity and technical difficulties for studying gene and protein expression in the Plasmodium falciparum parasite. Pregnancy malaria offers a model approach for vaccine development: recent findings have elucidated the basis for disease pathogenesis and protective immunity in this syndrome, and this understanding has focused the effort to identify the optimal antigens for a pregnancy malaria vaccine. In parallel, functional genomics tools are overcoming several of the obstacles for studying protein expression in the malaria parasite, vastly accelerating the pace for antigen discovery. Together, these conceptual and technological advances allow a rational approach to vaccine antigen selection, in which a finite number of antigens are selected from the entire genome by merit of the expression patterns and specific features. These candidate antigens are then subjected to detailed studies according to criteria established by the understanding of pathogenesis and protective immunity, to identify the optimal antigens for inclusion in subunit vaccines.

  6. Pooled deep sequencing of Plasmodium falciparum isolates: an efficient and scalable tool to quantify prevailing malaria drug-resistance genotypes.

    PubMed

    Taylor, Steve M; Parobek, Christian M; Aragam, Nash; Ngasala, Billy E; Mårtensson, Andreas; Meshnick, Steven R; Juliano, Jonathan J

    2013-12-15

    Molecular surveillance for drug-resistant malaria parasites requires reliable, timely, and scalable methods. These data may be efficiently produced by genotyping parasite populations using second-generation sequencing (SGS). We designed and validated a SGS protocol to quantify mutant allele frequencies in the Plasmodium falciparum genes dhfr and dhps in mixed isolates. We applied this new protocol to field isolates from children and compared it to standard genotyping using Sanger sequencing. The SGS protocol accurately quantified dhfr and dhps allele frequencies in a mixture of parasite strains. Using SGS of DNA that was extracted and then pooled from individual isolates, we estimated mutant allele frequencies that were closely correlated to those estimated by Sanger sequencing (correlations, >0.98). The SGS protocol obviated most molecular steps in conventional methods and is cost saving for parasite populations >50. This SGS genotyping method efficiently and reproducibly estimates parasite allele frequencies within populations of P. falciparum for molecular epidemiologic studies.

  7. Acquisition of Antibodies against Plasmodium falciparum Merozoites and Malaria Immunity in Young Children and the Influence of Age, Force of Infection, and Magnitude of Response

    PubMed Central

    Stanisic, Danielle I.; Fowkes, Freya J. I.; Koinari, Melanie; Javati, Sarah; Lin, Enmoore; Kiniboro, Benson; Richards, Jack S.; Robinson, Leanne J.; Schofield, Louis; Kazura, James W.; King, Christopher L.; Zimmerman, Peter; Felger, Ingrid; Siba, Peter M.

    2014-01-01

    Individuals in areas of Plasmodium falciparum endemicity develop immunity to malaria after repeated exposure. Knowledge of the acquisition and nature of protective immune responses to P. falciparum is presently limited, particularly for young children. We examined antibodies (IgM, IgG, and IgG subclasses) to merozoite antigens and their relationship to the prospective risk of malaria in children 1 to 4 years of age in a region of malaria endemicity in Papua New Guinea. IgG, IgG1, and IgG3 responses generally increased with age, were higher in children with active infection, and reflected geographic heterogeneity in malaria transmission. Antigenic properties, rather than host factors, appeared to be the main determinant of the type of IgG subclass produced. High antibody levels were not associated with protection from malaria; in contrast, they were typically associated with an increased risk of malaria. Adjustment for malaria exposure, using a novel molecular measure of the force of infection by P. falciparum, accounted for much of the increased risk, suggesting that the antibodies were markers of higher exposure to P. falciparum. Comparisons between antibodies in this cohort of young children and in a longitudinal cohort of older children suggested that the lack of protective association was explained by lower antibody levels among young children and that there is a threshold level of antibodies required for protection from malaria. Our results suggest that in populations with low immunity, such as young children, antibodies to merozoite antigens may act as biomarkers of malaria exposure and that, with increasing exposure and responses of higher magnitude, antibodies may act as biomarkers of protective immunity. PMID:25422270

  8. Selection of drug resistance-mediating Plasmodium falciparum genetic polymorphisms by seasonal malaria chemoprevention in Burkina Faso.

    PubMed

    Somé, Anyirékun Fabrice; Zongo, Issaka; Compaoré, Yves-Daniel; Sakandé, Souleymane; Nosten, François; Ouédraogo, Jean-Bosco; Rosenthal, Philip J

    2014-07-01

    Seasonal malaria chemoprevention (SMC), with regular use of amodiaquine plus sulfadoxine-pyrimethamine (AQ/SP) during the transmission season, is now a standard malaria control measure in the Sahel subregion of Africa. Another strategy under study is SMC with dihydroartemisinin plus piperaquine (DP). Plasmodium falciparum single nucleotide polymorphisms (SNPs) in P. falciparum crt (pfcrt), pfmdr1, pfdhfr, and pfdhps are associated with decreased response to aminoquinoline and antifolate antimalarials and are selected by use of these drugs. To characterize selection by SMC of key polymorphisms, we assessed 13 SNPs in P. falciparum isolated from children aged 3 to 59 months living in southwestern Burkina Faso and randomized to receive monthly DP or AQ/SP for 3 months in 2009. We compared SNP prevalence before the onset of SMC and 1 month after the third treatment in P. falciparum PCR-positive samples from 120 randomly selected children from each treatment arm and an additional 120 randomly selected children from a control group that did not receive SMC. The prevalence of relevant mutations was increased after SMC with AQ/SP. Significant selection was seen for pfcrt 76T (68.5% to 83.0%, P = 0.04), pfdhfr 59R (54.8% to 83.3%, P = 0.0002), and pfdhfr 108N (55.0% to 87.2%, P = 0.0001), with trends toward selection of pfmdr1 86Y, pfdhfr 51I, and pfdhps 437G. After SMC with DP, only borderline selection of wild-type pfmdr1 D1246 (mutant; 7.7% to 0%, P = 0.05) was seen. In contrast to AQ/SP, SMC with DP did not clearly select for known resistance-mediating polymorphisms. SMC with AQ/SP, but not DP, may hasten the development of resistance to components of this regimen. (This study has been registered at ClinicalTrials.gov under registration no. NCT00941785.).

  9. Kinetics of B cell responses to Plasmodium falciparum erythrocyte membrane protein 1 in Ghanaian women naturally exposed to malaria parasites.

    PubMed

    Ampomah, Paulina; Stevenson, Liz; Ofori, Michael F; Barfod, Lea; Hviid, Lars

    2014-06-01

    Naturally acquired protective immunity to Plasmodium falciparum malaria takes years to develop. It relies mainly on Abs, particularly IgG specific for Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins on the infected erythrocyte surface. It is only partially understood why acquisition of clinical protection takes years to develop, but it probably involves a range of immune-evasive parasite features, not least of which are PfEMP1 polymorphism and clonal variation. Parasite-induced subversion of immunological memory and expansion of "atypical" memory B cells may also contribute. In this first, to our knowledge, longitudinal study of its kind, we measured B cell subset composition, as well as PfEMP1-specific Ab levels and memory B cell frequencies, in Ghanaian women followed from early pregnancy up to 1 y after delivery. Cell phenotypes and Ag-specific B cell function were assessed three times during and after pregnancy. Levels of IgG specific for pregnancy-restricted, VAR2CSA-type PfEMP1 increased markedly during pregnancy and declined after delivery, whereas IgG levels specific for two PfEMP1 proteins not restricted to pregnancy did not. Changes in VAR2CSA-specific memory B cell frequencies showed typical primary memory induction among primigravidae and recall expansion among multigravidae, followed by contraction postpartum in all. No systematic changes in the frequencies of memory B cells specific for the two other PfEMP1 proteins were identified. The B cell subset analysis confirmed earlier reports of high atypical memory B cell frequencies among residents of P. falciparum-endemic areas, and indicated an additional effect of pregnancy. Our study provides new knowledge regarding immunity to P. falciparum malaria and underpins efforts to develop PfEMP1-based vaccines against this disease.

  10. Risk factors for Plasmodium falciparum and Plasmodium vivax gametocyte carriage in Papua New Guinean children with uncomplicated malaria.

    PubMed

    Karl, Stephan; Laman, Moses; Moore, Brioni R; Benjamin, John M; Salib, Mary; Lorry, Lina; Maripal, Samuel; Siba, Peter; Robinson, Leanne J; Mueller, Ivo; Davis, Timothy M E

    2016-08-01

    There are limited data on gametocytaemia risk factors before/after treatment with artemisinin combination therapy in children from areas with transmission of multiple Plasmodium species. We utilised data from a randomised trial comparing artemether-lumefantrine (AL) and artemisinin-naphthoquine (AN) in 230 Papua New Guinean children aged 0.5-5 years with uncomplicated malaria in whom determinants of gametocytaemia by light microscopy were assessed at baseline using logistic regression and during follow-up using multilevel mixed effects modelling. Seventy-four (32%) and 18 (8%) children presented with P. falciparum and P. vivax gametocytaemia, respectively. Baseline P. falciparum gametocytaemia was associated with Hackett spleen grade 1 (odds ratio (95% CI) 4.01 (1.60-10.05) vs grade 0; P<0.001) and haemoglobin (0.95 (0.92-0.97) per 1g/L increase; P<0.001), and P. falciparum asexual parasitaemia in slide-positive cases (0.36 (0.19-0.68) for a 10-fold increase; P=0.002). Baseline P. vivax gametocytaemia was associated with Hackett grade 2 (12.66 (1.31-122.56); P=0.028), mixed P. falciparum/vivax infection (0.16 (0.03-1.00); P=0.050), P. vivax asexual parasitaemia (5.68 (0.98-33.04); P=0.053) and haemoglobin (0.94 (0.88-1.00); P=0.056). For post-treatment P. falciparum gametocytaemia, independent predictors were AN vs AL treatment (4.09 (1.43-11.65)), haemoglobin (0.95 (0.93-0.97)), presence/absence of P. falciparum asexual forms (3.40 (1.66-0.68)) and day post-treatment (0.086 (0.82-0.90)) (P<0.001). Post-treatment P. vivax gametocytaemia was predicted by presence of P. vivax asexual forms (596 (12-28,433); P<0.001). Consistent with slow P. falciparum gametocyte maturation, low haemoglobin, low asexual parasite density and higher spleen grading, markers of increased prior infection exposure/immunity, were strong associates of pre-treatment gametocyte positivity. The persistent inverse association between P. falciparum gametocytaemia and haemoglobin during follow

  11. Risk factors for Plasmodium falciparum and Plasmodium vivax gametocyte carriage in Papua New Guinean children with uncomplicated malaria.

    PubMed

    Karl, Stephan; Laman, Moses; Moore, Brioni R; Benjamin, John M; Salib, Mary; Lorry, Lina; Maripal, Samuel; Siba, Peter; Robinson, Leanne J; Mueller, Ivo; Davis, Timothy M E

    2016-08-01

    There are limited data on gametocytaemia risk factors before/after treatment with artemisinin combination therapy in children from areas with transmission of multiple Plasmodium species. We utilised data from a randomised trial comparing artemether-lumefantrine (AL) and artemisinin-naphthoquine (AN) in 230 Papua New Guinean children aged 0.5-5 years with uncomplicated malaria in whom determinants of gametocytaemia by light microscopy were assessed at baseline using logistic regression and during follow-up using multilevel mixed effects modelling. Seventy-four (32%) and 18 (8%) children presented with P. falciparum and P. vivax gametocytaemia, respectively. Baseline P. falciparum gametocytaemia was associated with Hackett spleen grade 1 (odds ratio (95% CI) 4.01 (1.60-10.05) vs grade 0; P<0.001) and haemoglobin (0.95 (0.92-0.97) per 1g/L increase; P<0.001), and P. falciparum asexual parasitaemia in slide-positive cases (0.36 (0.19-0.68) for a 10-fold increase; P=0.002). Baseline P. vivax gametocytaemia was associated with Hackett grade 2 (12.66 (1.31-122.56); P=0.028), mixed P. falciparum/vivax infection (0.16 (0.03-1.00); P=0.050), P. vivax asexual parasitaemia (5.68 (0.98-33.04); P=0.053) and haemoglobin (0.94 (0.88-1.00); P=0.056). For post-treatment P. falciparum gametocytaemia, independent predictors were AN vs AL treatment (4.09 (1.43-11.65)), haemoglobin (0.95 (0.93-0.97)), presence/absence of P. falciparum asexual forms (3.40 (1.66-0.68)) and day post-treatment (0.086 (0.82-0.90)) (P<0.001). Post-treatment P. vivax gametocytaemia was predicted by presence of P. vivax asexual forms (596 (12-28,433); P<0.001). Consistent with slow P. falciparum gametocyte maturation, low haemoglobin, low asexual parasite density and higher spleen grading, markers of increased prior infection exposure/immunity, were strong associates of pre-treatment gametocyte positivity. The persistent inverse association between P. falciparum gametocytaemia and haemoglobin during follow

  12. Molecular Identification of Falciparum Malaria and Human Tuberculosis Co-Infections in Mummies from the Fayum Depression (Lower Egypt)

    PubMed Central

    Bianucci, Raffaella; Welte, Beatrix; Nerlich, Andreas G.; Kun, Jürgen F. J.; Pusch, Carsten M.

    2013-01-01

    Due to the presence of the lake Quarun and to the particular nature of its irrigation system, it has been speculated that the Fayum, a large depression 80 kilometers south- west of modern Cairo, was exposed to the hazards of malaria in historic times. Similarly, it has been speculated that, in the same area, also human tuberculosis might have been far more widespread in the antiquity than in its recent past. If these hypotheses were confirmed, it would imply that frequent cases of co-infection between the two pathogens might have occurred in ancient populations. To substantiate those speculations, molecular analyses were carried out on sixteen mummified heads recovered from the necropolis of Abusir el Meleq (Fayum) dating from the 3rd Intermediate Period (1064- 656 BC) to the Roman Period (30 BC- 300 AD). Soft tissue biopsies were used for DNA extractions and PCR amplifications using well-suited protocols. A partial 196-bp fragment of Plasmodium falciparum apical membrane antigen 1 gene and a 123-bp fragment of the Mycobacterium tuberculosis complex insertion sequence IS6110 were amplified and sequenced in six and five of the sixteen specimens, respectively. A 100% concordance rates between our sequences and those of P. falciparum and M. tuberculosis complex ones were obtained. Lastly, concomitant PCR amplification of P. falciparum and M. tuberculosis complex DNA specific fragments was obtained in four mummies, three of which are 14 C dated to the Late and Graeco-Roman Periods. Our data confirm that the hydrography of Fayum was extremely conducive to the spread of malaria. They also support the notion that the agricultural boom and dense crowding occurred in this region, especially under the Ptolemies, highly increased the probability for the manifestation and spread of tuberculosis. Here we extend back-wards to ca. 800 BC new evidence for malaria tropica and human tuberculosis co-occurrence in ancient Lower Egypt. PMID:23565222

  13. Interactions between Plasmodium falciparum skeleton-binding protein 1 and the membrane skeleton of malaria-infected red blood cells

    PubMed Central

    Buckingham, Donna W.; Blanc, Lionel; Hale, John; Guo, Xinhua; Pei, Xinhong; Herrmann, Susann; Hanssen, Eric G.; Coppel, Ross L.; Mohandas, Narla; An, Xiuli; Cooke, Brian M.

    2015-01-01

    During development inside red blood cells (RBCs), Plasmodium falciparum malaria parasites export proteins that associate with the RBC membrane skeleton. These interactions cause profound changes to the biophysical properties of RBCs that underpin the often severe and fatal clinical manifestations of falciparum malaria. P. falciparum erythrocyte membrane protein 1 (PfEMP1) is one such exported parasite protein that plays a major role in malaria pathogenesis since its exposure on the parasitised RBC surface mediates their adhesion to vascular endothelium and placental syncytioblasts. En route to the RBC membrane skeleton, PfEMP1 transiently associates with Maurer's clefts (MCs), parasite-derived membranous structures in the RBC cytoplasm. We have previously shown that a resident MC protein, skeleton-binding protein 1 (SBP1), is essential for the placement of PfEMP1 onto the RBC surface and hypothesised that the function of SBP1 may be to target MCs to the RBC membrane. Since this would require additional protein interactions, we set out to identify binding partners for SBP1. Using a combination of approaches, we have defined the region of SBP1 that binds specifically to defined subdomains of two major components of the RBC membrane skeleton, protein 4.1R and spectrin. We show that these interactions serve as one mechanism to anchor MCs to the RBC membrane skeleton, however, while they appear to be necessary, they are not sufficient for the translocation of PfEMP1 onto the RBC surface. The N-terminal domain of SBP1 that resides within the lumen of MCs clearly plays an essential, but presently unknown role in this process. PMID:25883090

  14. Interactions between Plasmodium falciparum skeleton-binding protein 1 and the membrane skeleton of malaria-infected red blood cells.

    PubMed

    Kats, Lev M; Proellocks, Nicholas I; Buckingham, Donna W; Blanc, Lionel; Hale, John; Guo, Xinhua; Pei, Xinhong; Herrmann, Susann; Hanssen, Eric G; Coppel, Ross L; Mohandas, Narla; An, Xiuli; Cooke, Brian M

    2015-07-01

    During development inside red blood cells (RBCs), Plasmodium falciparum malaria parasites export proteins that associate with the RBC membrane skeleton. These interactions cause profound changes to the biophysical properties of RBCs that underpin the often severe and fatal clinical manifestations of falciparum malaria. P. falciparum erythrocyte membrane protein 1 (PfEMP1) is one such exported parasite protein that plays a major role in malaria pathogenesis since its exposure on the parasitised RBC surface mediates their adhesion to vascular endothelium and placental syncytioblasts. En route to the RBC membrane skeleton, PfEMP1 transiently associates with Maurer's clefts (MCs), parasite-derived membranous structures in the RBC cytoplasm. We have previously shown that a resident MC protein, skeleton-binding protein 1 (SBP1), is essential for the placement of PfEMP1 onto the RBC surface and hypothesised that the function of SBP1 may be to target MCs to the RBC membrane. Since this would require additional protein interactions, we set out to identify binding partners for SBP1. Using a combination of approaches, we have defined the region of SBP1 that binds specifically to defined sub-domains of two major components of the RBC membrane skeleton, protein 4.1R and spectrin. We show that these interactions serve as one mechanism to anchor MCs to the RBC membrane skeleton, however, while they appear to be necessary, they are not sufficient for the translocation of PfEMP1 onto the RBC surface. The N-terminal domain of SBP1 that resides within the lumen of MCs clearly plays an essential, but presently unknown role in this process.

  15. Inhibition of Plasmodium falciparum proliferation in vitro by double-stranded RNA nanoparticle against malaria topoisomerase II.

    PubMed

    Attasart, Pongsopee; Boonma, Siriwan; Sunintaboon, Panya; Tanwilai, Dolpawan; Pothikasikorn, Jinrapa; Noonpakdee, Wilai Tienrungroj

    2016-05-01

    The need to develop new effective antimalarial agents is urgent due to the rapid emergence of drug resistance to all current drugs by the most virulent human malaria parasite, Plasmodium falciparum. A promising avenue is in the development of antimalarials based on RNA interference targeting expression of malaria parasite vital genes, viz. DNA topoisomerase II gene (PfTOP2). Biodegradable chitosan nanoparticle system has proven to be effective in delivering DNA and small double-stranded interfering RNA to target cells. We have employed a long double-stranded (dsRNA) targeting the coding region of PfTOP2 that is complexed with chitosan nanoparticles in order to interfere with the cognate mRNA expression and examined its effect on P. falciparum growth in culture. Exposure of ring stage-infected erythrocytes to 10 μg/ml PfTOP2 chitosan/dsRNA nanoparticles for 48 h resulted in 71% growth inhibition as determined by [(3)H] hypoxanthine incorporation and microscopic assays, compared with 41% inhibition using an equivalent amount of free PfTOP2 dsRNA or 12% with unrelated chitosan/dsRNA nanoparticles. This inhibition was shown to occur during maturation of trophozoite to schizont stages. RT-PCR analysis indicated 56% and 38% decrease in PfTOP2 transcript levels in P. falciparum trophozoites treated with PfTOP2 dsRNA nanoparticles and free PfTOP2 dsRNA respectively. These results suggest that chitosan-based nanoparticles might be a useful tool for delivering dsRNA into malaria parasites.

  16. Electrocardiographic safety evaluation of dihydroartemisinin piperaquine in the treatment of uncomplicated falciparum malaria.

    PubMed

    Mytton, Oliver T; Ashley, Elizabeth A; Peto, Leon; Price, Ric N; La, Yar; Hae, Rae; Singhasivanon, Pratap; White, Nicholas J; Nosten, François

    2007-09-01

    Dihydroartemisinin-piperaquine (DP) could become a leading fixed combination malaria treatment worldwide. Although there is accumulating evidence of efficacy and safety from clinical trials, data on cardiotoxicity are limited. In two randomized controlled trials in Thailand, 56 patients had ECGs performed before treatment, 4 hours after the first dose, and 4 hours after the last dose. The mean (95% CI) changes in QTc interval (Bazett's correction) were 2 (-6 to 9) ms and 14 (7 to 21) ms, respectively. These small changes on the third day of treatment are similar to those observed elsewhere in the convalescent phase following antimalarial treatment with drugs known to have no cardiac effects and are therefore likely to result from recovery from acute malaria and not the treatment given. At therapeutic doses, DP does not have clinically significant effects on the electrocardiogram. PMID:17827358

  17. Polymorphism at the apical membrane antigen 1 gene (AMA1) of the malaria parasite Plasmodium falciparum in a Vietnamese population.

    PubMed

    Quang, Nguyen Duc; Hoa, Phan Thi Phuong; Tuan, Mai Sy; Viet, Nguyen Xuan; Jalloh, Amadu; Matsuoka, Hiroyuki

    2009-06-01

    The patterns of molecular evolution of the most diverse region of the apical membrane antigen 1 (AMA1) gene in Plasmodium falciparum from a Vietnamese subpopulation (Bao Loc) were investigated. Within the Bao Loc population, the sequenced gene region showed relatively high allelic and nucleotide diversity (0.985 and 0.02694, respectively). Further, the level of population recombination was substantial, resulting in a significant decay of linkage disequilibrium along the gene region. The results suggest that AMA1 is a useful genetic marker for studying the relationships between adaptation of parasite populations (to the human host immune system) and malaria epidemiology.

  18. Evidence of Plasmodium falciparum Malaria Multidrug Resistance to Artemisinin and Piperaquine in Western Cambodia: Dihydroartemisinin-Piperaquine Open-Label Multicenter Clinical Assessment.

    PubMed

    Leang, Rithea; Taylor, Walter R J; Bouth, Denis Mey; Song, Lijiang; Tarning, Joel; Char, Meng Chuor; Kim, Saorin; Witkowski, Benoit; Duru, Valentine; Domergue, Anais; Khim, Nimol; Ringwald, Pascal; Menard, Didier

    2015-08-01

    Western Cambodia is recognized as the epicenter of Plasmodium falciparum multidrug resistance. Recent reports of the efficacy of dihydroartemisinin (DHA)-piperaquine (PP), the latest of the artemisinin-based combination therapies (ACTs) recommended by the WHO, have prompted further investigations. The clinical efficacy of dihydroartemisinin-piperaquine in uncomplicated falciparum malaria was assessed in western and eastern Cambodia over 42 days. Day 7 plasma piperaquine concentrations were measured and day 0 isolates tested for in vitro susceptibilities to piperaquine and mefloquine, polymorphisms in the K13 gene, and the copy number of the Pfmdr-1 gene. A total of 425 patients were recruited in 2011 to 2013. The proportion of patients with recrudescent infections was significantly higher in western (15.4%) than in eastern (2.5%) Cambodia (P <10(-3)). Day 7 plasma PP concentrations and median 50% inhibitory concentrations (IC50) of PP were independent of treatment outcomes, in contrast to median mefloquine IC50, which were found to be lower for isolates from patients with recrudescent infections (18.7 versus 39.7 nM; P = 0.005). The most significant risk factor associated with DHA-PP treatment failure was infection by parasites carrying the K13 mutant allele (odds ratio [OR], 17.5; 95% confidence interval [CI], 1 to 308; P = 0.04). Our data show evidence of P. falciparum resistance to PP in western Cambodia, an area of widespread artemisinin resistance. New therapeutic strategies, such as the use of triple ACTs, are urgently needed and must be tested. (This study has been registered at the Australian New Zealand Clinical Trials Registry under registration no. ACTRN12614000344695.). PMID:26014949

  19. Evidence of Plasmodium falciparum Malaria Multidrug Resistance to Artemisinin and Piperaquine in Western Cambodia: Dihydroartemisinin-Piperaquine Open-Label Multicenter Clinical Assessment

    PubMed Central

    Leang, Rithea; Taylor, Walter R. J.; Bouth, Denis Mey; Song, Lijiang; Tarning, Joel; Char, Meng Chuor; Kim, Saorin; Witkowski, Benoit; Duru, Valentine; Domergue, Anais; Khim, Nimol

    2015-01-01

    Western Cambodia is recognized as the epicenter of Plasmodium falciparum multidrug resistance. Recent reports of the efficacy of dihydroartemisinin (DHA)-piperaquine (PP), the latest of the artemisinin-based combination therapies (ACTs) recommended by the WHO, have prompted further investigations. The clinical efficacy of dihydroartemisinin-piperaquine in uncomplicated falciparum malaria was assessed in western and eastern Cambodia over 42 days. Day 7 plasma piperaquine concentrations were measured and day 0 isolates tested for in vitro susceptibilities to piperaquine and mefloquine, polymorphisms in the K13 gene, and the copy number of the Pfmdr-1 gene. A total of 425 patients were recruited in 2011 to 2013. The proportion of patients with recrudescent infections was significantly higher in western (15.4%) than in eastern (2.5%) Cambodia (P <10−3). Day 7 plasma PP concentrations and median 50% inhibitory concentrations (IC50) of PP were independent of treatment outcomes, in contrast to median mefloquine IC50, which were found to be lower for isolates from patients with recrudescent infections (18.7 versus 39.7 nM; P = 0.005). The most significant risk factor associated with DHA-PP treatment failure was infection by parasites carrying the K13 mutant allele (odds ratio [OR], 17.5; 95% confidence interval [CI], 1 to 308; P = 0.04). Our data show evidence of P. falciparum resistance to PP in western Cambodia, an area of widespread artemisinin resistance. New therapeutic strategies, such as the use of triple ACTs, are urgently needed and must be tested. (This study has been registered at the Australian New Zealand Clinical Trials Registry under registration no. ACTRN12614000344695.) PMID:26014949

  20. Evidence of Plasmodium falciparum Malaria Multidrug Resistance to Artemisinin and Piperaquine in Western Cambodia: Dihydroartemisinin-Piperaquine Open-Label Multicenter Clinical Assessment.

    PubMed

    Leang, Rithea; Taylor, Walter R J; Bouth, Denis Mey; Song, Lijiang; Tarning, Joel; Char, Meng Chuor; Kim, Saorin; Witkowski, Benoit; Duru, Valentine; Domergue, Anais; Khim, Nimol; Ringwald, Pascal; Menard, Didier

    2015-08-01

    Western Cambodia is recognized as the epicenter of Plasmodium falciparum multidrug resistance. Recent reports of the efficacy of dihydroartemisinin (DHA)-piperaquine (PP), the latest of the artemisinin-based combination therapies (ACTs) recommended by the WHO, have prompted further investigations. The clinical efficacy of dihydroartemisinin-piperaquine in uncomplicated falciparum malaria was assessed in western and eastern Cambodia over 42 days. Day 7 plasma piperaquine concentrations were measured and day 0 isolates tested for in vitro susceptibilities to piperaquine and mefloquine, polymorphisms in the K13 gene, and the copy number of the Pfmdr-1 gene. A total of 425 patients were recruited in 2011 to 2013. The proportion of patients with recrudescent infections was significantly higher in western (15.4%) than in eastern (2.5%) Cambodia (P <10(-3)). Day 7 plasma PP concentrations and median 50% inhibitory concentrations (IC50) of PP were independent of treatment outcomes, in contrast to median mefloquine IC50, which were found to be lower for isolates from patients with recrudescent infections (18.7 versus 39.7 nM; P = 0.005). The most significant risk factor associated with DHA-PP treatment failure was infection by parasites carrying the K13 mutant allele (odds ratio [OR], 17.5; 95% confidence interval [CI], 1 to 308; P = 0.04). Our data show evidence of P. falciparum resistance to PP in western Cambodia, an area of widespread artemisinin resistance. New therapeutic strategies, such as the use of triple ACTs, are urgently needed and must be tested. (This study has been registered at the Australian New Zealand Clinical Trials Registry under registration no. ACTRN12614000344695.).

  1. In Vivo Efficacy and Tolerability of Artesunate-Azithromycin for the Treatment of Falciparum Malaria in Vietnam.

    PubMed

    Phong, Nguyen Chinh; Quang, Huynh Hong; Thanh, Nguyen Xuan; Trung, Trieu Nguyen; Dai, Bui; Shanks, G Dennis; Chavchich, Marina; Edstein, Michael D

    2016-07-01

    Safe and effective antimalarial drugs are required for the treatment of pregnant women. We report a 3-day regimen of artesunate (4 mg/kg/day)-azithromycin (25 mg/kg/day) (ASAZ) to be efficacious (polymerase chain reaction-corrected cure rate of 96.7%) and well tolerated in the treatment of Plasmodium falciparum malaria in children (N = 11) and adults (N = 19), in Vietnam in 2010. In comparison, the cure rate for artesunate (4 mg/kg on day 0, 2 mg/kg on days 1-6) was 90.0% in children (N = 7) and adults (N = 23). Because azithromycin is considered safe in pregnancy, our findings provide further evidence that ASAZ should be evaluated for the treatment of pregnant women with malaria. PMID:27215294

  2. Interactions between merozoite surface proteins 1, 6, and 7 of the malaria parasite Plasmodium falciparum.

    PubMed

    Kauth, Christian W; Woehlbier, Ute; Kern, Michaela; Mekonnen, Zeleke; Lutz, Rolf; Mücke, Norbert; Langowski, Jörg; Bujard, Hermann

    2006-10-20

    Merozoites of the malaria parasite Plasmodium falciparum expose at their surface a large multiprotein complex, composed of proteolytically processed, noncovalently associated products of at least three genes, msp-1, msp-6, and msp-7. During invasion of erythrocytes, this complex is shed from the surface except for a small glycosylphosphatidylinositol-anchored portion originating from MSP-1. The proteolytic cleavage separating the C-terminal portion of MSP-1 is required for successful invasion. Little is known about the structure and function of the abundant and essential multipartite complex. Using heterologously produced MSP-1, MSP-6, and MSP-7 in precursor and with the exception of MSP-7 in processed form, we have studied in vitro the complex formation between the different proteins to identify the interaction partners within the complex. Both MSP-6(36) and MSP-7 bind only to MSP-1 subunits that are shed, but although MSP-6(36) contacts just subunit p38, MSP-7 interacts with p83, p30, and p38. The intact C-terminal region of MSP-6 is required for the association with p38 as well as for its multimerization into tetramers. Furthermore, our data suggest that only the processed form and not the precursor form of MSP-1 interacts with MSP-6(36). MSP-6- as well as MSP-7-specific rabbit antibodies inhibit parasite multiplication in vitro as shown previously for antibodies directed against MSP-1. Our findings raise interesting questions with regard to proteolysis-mediated mechanisms of maturation of the MSP-1-MSP-6-MSP-7 complex and to the mode by which antibodies directed against this complex interfere with parasite multiplication.

  3. Genetic Resistance to Malaria Is Associated With Greater Enhancement of Immunoglobulin (Ig)M Than IgG Responses to a Broad Array of Plasmodium falciparum Antigens

    PubMed Central

    Arama, Charles; Skinner, Jeff; Doumtabe, Didier; Portugal, Silvia; Tran, Tuan M.; Jain, Aarti; Traore, Boubacar; Doumbo, Ogobara K.; Davies, David Huw; Troye-Blomberg, Marita; Dolo, Amagana; Felgner, Philip L.; Crompton, Peter D.

    2015-01-01

    Background. People of the Fulani ethnic group are more resistant to malaria compared with genetically distinct ethnic groups, such as the Dogon people, in West Africa, and studies suggest that this resistance is mediated by enhanced antibody responses to Plasmodium falciparum antigens. However, prior studies measured antibody responses to <0.1% of P falciparum proteins, so whether the Fulani mount an enhanced and broadly reactive immunoglobulin (Ig)M and IgG response to P falciparum remains unknown. In general, little is known about the extent to which host genetics influence the overall antigen specificity of IgM and IgG responses to natural infections. Methods. In a cross-sectional study in Mali, we collected plasma from asymptomatic, age-matched Fulani (n = 24) and Dogon (n = 22) adults with or without concurrent P falciparum infection. We probed plasma against a protein microarray containing 1087 P falciparum antigens and compared IgM and IgG profiles by ethnicity. Results. We found that the breadth and magnitude of P falciparum-specific IgM and IgG responses were significantly higher in the malaria-resistant Fulani versus the malaria-susceptible Dogon, and, unexpectedly, P falciparum-specific IgM responses more strongly distinguished the 2 ethnic groups. Conclusions. These findings point to an underappreciated role for IgM in protection from malaria, and they suggest that host genetics may influence the antigen specificity of IgM and IgG responses to infection. PMID:26361633

  4. Bilateral optic neuritis due to malaria.

    PubMed

    Chacko, Joseph G; Onteddu, Sanjeeva; Rosenbaum, Eric R

    2013-09-01

    Malaria is a mosquito-borne infectious disease caused by protists of the genus Plasmodium. Malaria is widespread in tropical regions around the equator, including much of sub-Saharan Africa, Asia, and the Americas, and uncommonly seen in the developed world. Although a variety of ocular manifestations have been linked to malaria, optic neuritis is rare. We report a patient who developed bilateral optic neuritis after he was treated successfully for acute falciparum malaria.

  5. High IFN-gamma and TNF production by peripheral NK cells of Colombian patients with different clinical presentation of Plasmodium falciparum

    PubMed Central

    2012-01-01

    Background In Colombia, Plasmodium falciparum infection rarely results in severe disease or mortality compared to infections in African populations. During natural infection NK cells exhibit a cytolytic effect and regulate dendritic cells, macrophages, neutrophils as well as affect antigen specific T and B cell responses. To characterize the NK cells in P. falciparum infected patients of a highly endemic region of Colombia, the degree of NK proliferation and production of IFN gamma and TNF production in these cells were explored. Methods Seventeen patients with acute and three with severe P. falciparum malaria patients from the Northwest region of the country were recruited in the study. In addition, 20 healthy controls were included: 10 from Medellin (no-transmission area) and 10 from the Uraba region (a malaria endemic area). Immunophenotypic analysis of peripheral mononuclear cells was performed by FACS to detect total number of NK cells, subtypes and intracellular IFNγ and TNF production by NK cells in the different patient groups. Results The total mean CD56+/CD3- NK cell proportions in acute and severe malaria subjects were 9.14% (7.15%CD56dim, 2.01%CD56bright) and 19.62% (16.05%CD56dim, 3.58%CD56bright), respectively, in contrast to healthy controls from endemic (total mean CD56+/CD3-1.2%) and non-endemic area (total mean CD56+/CD3- 0.67%). Analysis of basal IFNγ and TNF levels confirmed the CD56bright NK population as the main cytokine producer (p < 0.0001) in the groups affected with malaria, with the CD56dim NK cell exhibiting the highest potential of TNF production after stimulus in the acute malaria group. Conclusions The results confirm the important role of not only CD56bright but also of CD56dim NK cell populations as producers of the two cytokines in malaria patients in Colombia. PMID:22316273

  6. Efficacy of oral and intravenous artesunate in male Tanzanian adults with Plasmodium falciparum malaria and in vitro susceptibility to artemisinin, chloroquine, and mefloquine.

    PubMed

    Alin, M H; Kihamia, C M; Bjorkman, A; Bwijo, B A; Premji, Z; Mtey, G J; Ashton, M

    1995-12-01

    The clinical efficacy of oral and intravenous (iv) artesunate was compared in an open randomized trial in 50 male adult patients with uncomplicated Plasmodium falciparum malaria in Kibaha, Tanzania. Oral artesunate treatment was started with 2 x 50 mg initially followed by 50 mg 12 hr later and then 50 mg twice a day for four days (total dose = 550 mg or 9.6 mg/kg). Intravenous artesunate administration began with 2 x 0.8 mg/kg initially followed by 0.8 mg/kg 12 hr later and then 0.8 mg/kg twice a day for four days (total dose = 8.8 mg/kg). The mean +/- SD parasite clearance times (PCTs) were nearly identical at 23.4 +/- 5.9 hr and 24.2 +/- 7.2 hr after oral and iv administration, respectively. Mean +/- SD fever subsidence times (FSTs) were also similar at 18.7 +/- 8.3 hr and 21.0 +/- 4.8 hr, respectively. All patients remained negative for P. falciparum for at least 14 days. Recrudescence/reinfection occurred between days 21 and 28 in five of 25 patients (20%) after oral treatment and in four of 25 patients (16%) after iv treatment. The mean erythrocyte count and hemoglobin concentration were slightly reduced after iv treatment but remained in the normal range. Otherwise, there was no change in blood biochemistry, hematology, and electrocardiograms monitored prior to and during the last dose. It is concluded that treatment with oral and iv artesunate was equally efficacious and well tolerated. A 24-hr in vitro susceptibility test of P. falciparum to artemisinin, chloroquine, and mefloquine was performed in samples from all patients. The three compounds exhibited 100% inhibition with the exception of three isolates, which showed chloroquine resistance. Parameter estimates of a sigmoid Emax model (drug concentration at which 50% of the growth inhibition occurs [EC50]), the sigmoidicity factor s and EC95 fitted to the growth inhibition data differed between compounds and isolates, indicating different sensitivity of P. falciparum isolates. There was no correlation

  7. Active case detection, treatment of falciparum malaria with combined chloroquine and sulphadoxine/pyrimethamine and vivax malaria with chloroquine and molecular markers of anti-malarial resistance in the Republic of Vanuatu

    PubMed Central

    2010-01-01

    Background Chloroquine-resistant Plasmodium falciparum was first described in the Republic of Vanuatu in the early 1980s. In 1991, the Vanuatu Ministry of Health instituted new treatment guidelines for uncomplicated P. falciparum infection consisting of chloroquine/sulphadoxine-pyrimethamine combination therapy. Chloroquine remains the recommended treatment for Plasmodium vivax. Methods In 2005, cross-sectional blood surveys at 45 sites on Malo Island were conducted and 4,060 adults and children screened for malaria. Of those screened, 203 volunteer study subjects without malaria at the time of screening were followed for 13 weeks to observe peak seasonal incidence of infection. Another 54 subjects with malaria were followed over a 28-day period to determine efficacy of anti-malarial therapy; chloroquine alone for P. vivax and chloroquine/sulphadoxine-pyrimethamine for P. falciparum infections. Results The overall prevalence of parasitaemia by mass blood screening was 6%, equally divided between P. falciparum and P. vivax. Twenty percent and 23% of participants with patent P. vivax and P. falciparum parasitaemia, respectively, were febrile at the time of screening. In the incidence study cohort, after 2,303 person-weeks of follow-up, the incidence density of malaria was 1.3 cases per person-year with P. vivax predominating. Among individuals participating in the clinical trial, the 28-day chloroquine P. vivax cure rate was 100%. The 28-day chloroquine/sulphadoxine-pyrimethamine P. falciparum cure rate was 97%. The single treatment failure, confirmed by merozoite surface protein-2 genotyping, was classified as a day 28 late parasitological treatment failure. All P. falciparum isolates carried the Thr-76 pfcrt mutant allele and the double Asn-108 + Arg-59 dhfr mutant alleles. Dhps mutant alleles were not detected in the study sample. Conclusion Peak seasonal malaria prevalence on Malo Island reached hypoendemic levels during the study observation period. The only in

  8. Molecular inference of sources and spreading patterns of Plasmodium falciparum malaria parasites in internally displaced persons settlements in Myanmar-China border area.

    PubMed

    Lo, Eugenia; Zhou, Guofa; Oo, Winny; Lee, Ming-Chieh; Baum, Elisabeth; Felgner, Philip L; Yang, Zhaoqing; Cui, Liwang; Yan, Guiyun

    2015-07-01

    In Myanmar, civil unrest and establishment of internally displaced persons (IDP) settlement along the Myanmar-China border have impacted malaria transmission. The growing IDP populations raise deep concerns about health impact on local communities. Microsatellite markers were used to examine the source and spreading patterns of Plasmodium falciparum between IDP settlement and surrounding villages in Myanmar along the China border. Genotypic structure of P. falciparum was compared over the past three years from the same area and the demographic history was inferred to determine the source of recent infections. In addition, we examined if border migration is a factor of P. falciparum infections in China by determining gene flow patterns across borders. Compared to local community, the IDP samples showed a reduced and consistently lower genetic diversity over the past three years. A strong signature of genetic bottleneck was detected in the IDP samples. P. falciparum infections from the border regions in China were genetically similar to Myanmar and parasite gene flow was not constrained by geographical distance. Reduced genetic diversity of P. falciparum suggested intense malaria control within the IDP settlement. Human movement was a key factor to the spread of malaria both locally in Myanmar and across the international border.

  9. Plasmodium falciparum malaria in the Peruvian Amazon, a region of low transmission, is associated with immunologic memory.

    PubMed

    Clark, Eva H; Silva, Claudia J; Weiss, Greta E; Li, Shanping; Padilla, Carlos; Crompton, Peter D; Hernandez, Jean N; Branch, OraLee H

    2012-04-01

    The development of clinical immunity to Plasmodium falciparum malaria is thought to require years of parasite exposure, a delay often attributed to difficulties in developing protective antibody levels. In this study, we evaluated several P. falciparum vaccine candidate antigens, including apical membrane antigen 1 (AMA-1), circumsporozoite protein (CSP), erythrocyte binding antigen 175 (EBA-175), and the 19-kDa region of merozoite surface protein 1 (MSP1(19)). After observing a more robust antibody response to MSP1(19), we evaluated the magnitude and longevity of IgG responses specific to this antigen in Peruvian adults and children before, during, and after P. falciparum infection. In this low-transmission region, even one reported prior infection was sufficient to produce a positive anti-MSP1(19) IgG response for >5 months in the absence of reinfection. We also observed an expansion of the total plasmablast (CD19(+) CD27(+) CD38(high)) population in the majority of individuals shortly after infection and detected MSP1-specific memory B cells in a subset of individuals at various postinfection time points. This evidence supports our hypothesis that effective antimalaria humoral immunity can develop in low-transmission regions.

  10. Inhibition of malaria parasite Plasmodium falciparum development by crotamine, a cell penetrating peptide from the snake venom.

    PubMed

    El Chamy Maluf, S; Dal Mas, C; Oliveira, E B; Melo, P M; Carmona, A K; Gazarini, M L; Hayashi, M A F

    2016-04-01

    We show here that crotamine, a polypeptide from the South American rattlesnake venom with cell penetrating and selective anti-fungal and anti-tumoral properties, presents a potent anti-plasmodial activity in culture. Crotamine inhibits the development of the Plasmodium falciparum parasites in a dose-dependent manner [IC50 value of 1.87 μM], and confocal microscopy analysis showed a selective internalization of fluorescent-labeled crotamine into P. falciparum infected erythrocytes, with no detectable fluorescence in uninfected healthy erythrocytes. In addition, similarly to the crotamine cytotoxic effects, the mechanism underlying the anti-plasmodial activity may involve the disruption of parasite acidic compartments H(+) homeostasis. In fact, crotamine promoted a reduction of parasites organelle fluorescence loaded with the lysosomotropic fluorochrome acridine orange, in the same way as previously observed mammalian tumoral cells. Taken together, we show for the first time crotamine not only compromised the metabolism of the P. falciparum, but this toxin also inhibited the parasite growth. Therefore, we suggest this snake polypeptide as a promising lead molecule for the development of potential new molecules, namely peptidomimetics, with selectivity for infected erythrocytes and ability to inhibit the malaria infection by its natural affinity for acid vesicles. PMID:26806200

  11. Plasmodium falciparum malaria transmission indices in a highland village of the Ikopa River Valley near Antananarivo, Madagascar.

    PubMed

    Ralisoa, O; Rasamindrakotroka, A; Ravelojana, B; Rafarasoa, L; Randrianarisoa, E; Rakotoson, R; Bosman, A; Coluzzi, M

    1991-12-01

    Data are reported from a malaria survey carried out in June 1991 in the small village of Ankadimbazinba, near Miantso, about 45 km North-West of Antananarivo (Madagascar). The objective was to evaluate the level of transmission of P. falciparum by entomological, parasitological and serological indices. All indices were found consistent with the description of a focus of hyperendemic transmission dependent on the presence of An. funestus at high density, corresponding to more than 50 females per house collected by hand catch. The positivity rate for the circumsporozoite protein (CS) of P. falciparum in blood-fed or gravid An. funestus was 2.0% (11/562) in the house resting sample. The parasite rate in the village population was 47.9% reaching 68.4% in the 0-14 age group and the gametocyte rate in the total sample was 25.0%. The seroprevalence of P. falciparum antisporozoite antibodies was 40.0% in children under 15 years old, 84.2% in the 15-29 age group and 90.9% in the over 29 age group.

  12. Longitudinal survey in an endemic region of plasma soluble interleukin-2 receptor and antibody levels in Plasmodium falciparum malaria.

    PubMed Central

    Chumpitazi, B F; Peyron, F; Simon, J; Boudin, C; Sheick-Zakiuddin, I; Picot, S; Ambroise-Thomas, P

    1990-01-01

    A survey involving 81 individuals living in Dafinso and Vallée du Kou no. 4 (near Bobo-Dioulasso), Burkina Faso, was performed in June 1987, August to September 1987, and January 1988, respectively, at the beginning of, during, and after the transmission season of malaria. The clinical longitudinal study during the transmission period allowed us to define three different groups in terms of both age and occurrence of malaria attack (5,000 Plasmodium falciparum per mm3 of blood and axillary fever of greater than 37.7 degrees C) as follows: group 1, persons less than or equal to 15 years old who had at least one malaria attack during the transmission period; group 2, individuals less than or equal to 15 years old who did not have any malaria attacks; and group 3, individuals considered to be protected (adults greater than 15 years old with no malaria attacks). Soluble interleukin-2 receptor (sIL-2R) levels were found to be significantly increased (P less than 0.001) in the first two groups (1,047 +/- 481 U/ml [mean +/- standard deviation]) as compared with the adult group (605 +/- 307 U/ml). Considering all the groups, no significant difference was observed between observation periods. Levels of sIL-2R were inversely correlated (r = -0.39, n = 237, P less than 0.01) with age (range, 4 to 67 years). Negative correlations were also noticed between the levels of sIL-2R and those of antibodies to somatic antigen of P. falciparum (immunoglobulin G [IgG] class [r = -0.33, n = 237, P less than 0.01] and IgM class [r = -0.20, n = 237, P less than 0.05]). IgG antibody levels to somatic antigen were correlated with age, but IgM antibody levels to somatic antigen were not. The possible role played by sIL-2R in effector mechanisms against malaria is discussed. PMID:2199518

  13. A Unique Virulence Gene Occupies a Principal Position in Immune Evasion by the Malaria Parasite Plasmodium falciparum.

    PubMed

    Ukaegbu, Uchechi E; Zhang, Xu; Heinberg, Adina R; Wele, Mamadou; Chen, Qijun; Deitsch, Kirk W

    2015-05-01

    Mutually exclusive gene expression, whereby only one member of a multi-gene family is selected for activation, is used by the malaria parasite Plasmodium falciparum to escape the human immune system and perpetuate long-term, chronic infections. A family of genes called var encodes the chief antigenic and virulence determinant of P. falciparum malaria. var genes are transcribed in a mutually exclusive manner, with switching between active genes resulting in antigenic variation. While recent work has shed considerable light on the epigenetic basis for var gene activation and silencing, how switching is controlled remains a mystery. In particular, switching seems not to be random, but instead appears to be coordinated to result in timely activation of individual genes leading to sequential waves of antigenically distinct parasite populations. The molecular basis for this apparent coordination is unknown. Here we show that var2csa, an unusual and highly conserved var gene, occupies a unique position within the var gene switching hierarchy. Induction of switching through the destabilization of var specific chromatin using both genetic and chemical methods repeatedly led to the rapid and exclusive activation of var2csa. Additional experiments demonstrated that these represent "true" switching events and not simply de-silencing of the var2csa promoter, and that activation is limited to the unique locus on chromosome 12. Combined with translational repression of var2csa transcripts, frequent "default" switching to this locus and detection of var2csa untranslated transcripts in non-pregnant individuals, these data suggest that var2csa could play a central role in coordinating switching, fulfilling a prediction made by mathematical models derived from population switching patterns. These studies provide the first insights into the mechanisms by which var gene switching is coordinated as well as an example of how a pharmacological agent can disrupt antigenic variation in

  14. A Unique Virulence Gene Occupies a Principal Position in Immune Evasion by the Malaria Parasite Plasmodium falciparum

    PubMed Central

    Heinberg, Adina R.; Wele, Mamadou; Chen, Qijun; Deitsch, Kirk W.

    2015-01-01

    Mutually exclusive gene expression, whereby only one member of a multi-gene family is selected for activation, is used by the malaria parasite Plasmodium falciparum to escape the human immune system and perpetuate long-term, chronic infections. A family of genes called var encodes the chief antigenic and virulence determinant of P. falciparum malaria. var genes are transcribed in a mutually exclusive manner, with switching between active genes resulting in antigenic variation. While recent work has shed considerable light on the epigenetic basis for var gene activation and silencing, how switching is controlled remains a mystery. In particular, switching seems not to be random, but instead appears to be coordinated to result in timely activation of individual genes leading to sequential waves of antigenically distinct parasite populations. The molecular basis for this apparent coordination is unknown. Here we show that var2csa, an unusual and highly conserved var gene, occupies a unique position within the var gene switching hierarchy. Induction of switching through the destabilization of var specific chromatin using both genetic and chemical methods repeatedly led to the rapid and exclusive activation of var2csa. Additional experiments demonstrated that these represent “true” switching events and not simply de-silencing of the var2csa promoter, and that activation is limited to the unique locus on chromosome 12. Combined with translational repression of var2csa transcripts, frequent “default” switching to this locus and detection of var2csa untranslated transcripts in non-pregnant individuals, these data suggest that var2csa could play a central role in coordinating switching, fulfilling a prediction made by mathematical models derived from population switching patterns. These studies provide the first insights into the mechanisms by which var gene switching is coordinated as well as an example of how a pharmacological agent can disrupt antigenic variation

  15. Prevalence of Plasmodium falciparum Molecular Markers of Antimalarial Drug Resistance in a Residual Malaria Focus Area in Sabah, Malaysia

    PubMed Central

    Mohd Abd Razak, Mohd Ridzuan; Abdullah, Noor Rain; Sastu, Umi Rubiah; Imwong, Mallika; Muniandy, Prem Kumar; Saat, Muhammad Nor Farhan; Muhammad, Amirrudin; Jelip, Jenarun; Tikuson, Moizin; Yusof, Norsalleh; Rundi, Christina; Mudin, Rose Nani; Syed Mohamed, Ami Fazlin

    2016-01-01

    Chloroquine (CQ) and fansidar (sulphadoxine-pyrimethamine, SP) were widely used for treatment of Plasmodium falciparum for several decades in Malaysia prior to the introduction of Artemisinin-based Combination Therapy (ACT) in 2008. Our previous study in Kalabakan, located in south-east coast of Sabah showed a high prevalence of resistance to CQ and SP, suggesting the use of the treatment may no longer be effective in the area. This study aimed to provide a baseline data of antimalarial drug resistant markers on P. falciparum isolates in Kota Marudu located in the north-east coast of Sabah. Mutations on genes associated with CQ (pfcrt and pfmdr1) and SP (pfdhps and pfdhfr) were assessed by PCR amplification and restriction fragment length polymorphism. Mutations on the kelch13 marker (K13) associated with artemisinin resistance were determined by DNA sequencing technique. The assessment of pfmdr1 copy number variation associated with mefloquine resistant was done by real-time PCR technique. A low prevalence (6.9%) was indicated for both pfcrt K76T and pfmdr1 N86Y mutations. All P. falciparum isolates harboured the pfdhps A437G mutation. Prevalence of pfdhfr gene mutations, S108N and I164L, were 100% and 10.3%, respectively. Combining the different resistant markers, only two isolates were conferred to have CQ and SP treatment failure markers as they contained mutant alleles of pfcrt and pfmdr1 together with quintuple pfdhps/pfdhfr mutation (combination of pfdhps A437G+A581G and pfdhfr C59R+S108N+I164L). All P. falciparum isolates carried single copy number of pfmdr1 and wild type K13 marker. This study has demonstrated a low prevalence of CQ and SP resistance alleles in the study area. Continuous monitoring of antimalarial drug efficacy is warranted and the findings provide information for policy makers in ensuring a proper malaria control. PMID:27788228

  16. Various pfcrt and pfmdr1 genotypes of Plasmodium falciparum cocirculate with P. malariae, P. ovale spp., and P. vivax in northern Angola.

    PubMed

    Fançony, Cláudia; Gamboa, Dina; Sebastião, Yuri; Hallett, Rachel; Sutherland, Colin; Sousa-Figueiredo, José Carlos; Nery, Susana Vaz

    2012-10-01

    Artemisinin-based combination therapy for malaria has become widely available across Africa. Populations of Plasmodium falciparum that were previously dominated by chloroquine (CQ)-resistant genotypes are now under different drug selection pressures. P. malariae, P. ovale curtisi, and P. ovale wallikeri are sympatric with P. falciparum across the continent and are frequently present as coinfections. The prevalence of human Plasmodium species was determined by PCR using DNA from blood spots collected during a cross-sectional survey in northern Angola. P. falciparum was genotyped at resistance-associated loci in pfcrt and pfmdr1 by real-time PCR or by direct sequencing of amplicons. Of the 3,316 samples collected, 541 (16.3%) contained Plasmodium species infections; 477 (88.2%) of these were P. falciparum alone, 6.5% were P. falciparum and P. malariae together, and 1.1% were P. vivax alone. The majority of the remainder (3.7%) harbored P. ovale curtisi or P. ovale wallikeri alone or in combination with other species. Of 430 P. falciparum isolates genotyped for pfcrt, 61.6% carried the wild-type allele CVMNK at codons 72 to 76, either alone or in combination with the resistant allele CVIET. No other pfcrt allele was found. Wild-type alleles dominated at codons 86, 184, 1034, 1042, and 1246 of the pfmdr1 locus among the sequenced isolates. In contrast to previous studies, P. falciparum in the study area comprises an approximately equal mix of genotypes associated with CQ sensitivity and with CQ resistance, suggesting either lower drug pressure due to poor access to treatment in rural areas or a rapid impact of the policy change away from the use of standard monotherapies.

  17. Placental Malaria in Colombia: Histopathologic Findings in Plasmodium vivax and P. falciparum Infections

    PubMed Central

    Carmona-Fonseca, Jaime; Arango, Eliana; Maestre, Amanda

    2013-01-01

    Studies on gestational malaria and placental malaria have been scarce in malaria-endemic areas of the Western Hemisphere. To describe the histopathology of placental malaria in Colombia, a longitudinal descriptive study was conducted. In this study, 179 placentas were studied by histologic analysis (112 with gestational malaria and 67 negative for malaria). Placental malaria was confirmed in 22.35%, 50.0% had previous infections, and 47.5% had acute infections. Typical malaria-associated changes were observed in 37%. The most common changes were villitis, intervillitis, deciduitis, increased fibrin deposition, increased syncytial knots, mononuclear (monocytes/macrophages and lymphocytes), polymorphonuclear cell infiltration, and trophozoites in fetal erythrocytes. No association was found between type of placental changes observed and histopathologic classification of placental malaria. The findings are consistent with those reported for placental malaria in other regions. Plasmodium vivax was the main parasite responsible for placental and gestational malaria, but its role in the pathogenesis of placental malaria was not conclusive. PMID:23546807

  18. Network-based gene prediction for Plasmodium falciparum malaria towards genetics-based drug discovery

    PubMed Central

    2015-01-01

    Background Malaria is the most deadly parasitic infectious disease. Existing drug treatments have limited efficacy in malaria elimination, and the complex pathogenesis of the disease is not fully understood. Detecting novel malaria-associated genes not only contributes in revealing the disease pathogenesis, but also facilitates discovering new targets for anti-malaria drugs. Methods In this study, we developed a network-based approach to predict malaria-associated genes. We constructed a cross-species network to integrate human-human, parasite-parasite and human-parasite protein interactions. Then we extended the random walk algorithm on this network, and used known malaria genes as the seeds to find novel candidate genes for malaria. Results We validated our algorithms using 77 known malaria genes: 14 human genes and 63 parasite genes were ranked averagely within top 2% and top 4%, respectively among human and parasite genomes. We also evaluated our method for predicting novel malaria genes using a set of 27 genes with literature supporting evidence. Our approach ranked 12 genes within top 1% and 24 genes within top 5%. In addition, we demonstrated that top-ranked candied genes were enriched for drug targets, and identified commonalities underlying top-ranked malaria genes through pathway analysis. In summary, the candidate malaria-associated genes predicted by our data-driven approach have the potential to guide genetics-based anti-malaria drug discovery. PMID:26099491

  19. Assessing the impact of next-generation rapid diagnostic tests on Plasmodium falciparum malaria elimination strategies.

    PubMed

    Slater, Hannah C; Ross, Amanda; Ouédraogo, André Lin; White, Lisa J; Nguon, Chea; Walker, Patrick G T; Ngor, Pengby; Aguas, Ricardo; Silal, Sheetal P; Dondorp, Arjen M; La Barre, Paul; Burton, Robert; Sauerwein, Robert W; Drakeley, Chris; Smith, Thomas A; Bousema, Teun; Ghani, Azra C

    2015-12-01

    Mass-screen-and-treat and targeted mass-drug-administration strategies are being considered as a means to interrupt transmission of Plasmodium falciparum malaria. However, the effectiveness of such strategies will depend on the extent to which current and future diagnostics are able to detect those individuals who are infectious to mosquitoes. We estimate the relationship between parasite density and onward infectivity using sensitive quantitative parasite diagnostics and mosquito feeding assays from Burkina Faso. We find that a diagnostic with a lower detection limit of 200 parasites per microlitre would detect 55% of the infectious reservoir (the combined infectivity to mosquitoes of the whole population weighted by how often each individual is bitten) whereas a test with a limit of 20 parasites per microlitre would detect 83% and 2 parasites per microlitre would detect 95% of the infectious reservoir. Using mathematical models, we show that increasing the diagnostic sensitivity from 200 parasites per microlitre (equivalent to microscopy or current rapid diagnostic tests) to 2 parasites per microlitre would increase the number of regions where transmission could be interrupted with a mass-screen-and-treat programme from an entomological inoculation rate below 1 to one of up to 4. The higher sensitivity diagnostic could reduce the number of treatment rounds required to interrupt transmission in areas of lower prevalence. We predict that mass-screen-and-treat with a highly sensitive diagnostic is less effective than mass drug administration owing to the prophylactic protection provided to uninfected individuals by the latter approach. In low-transmission settings such as those in Southeast Asia, we find that a diagnostic tool with a sensitivity of 20 parasites per microlitre may be sufficient for targeted mass drug administration because this diagnostic is predicted to identify a similar village population prevalence compared with that currently detected using

  20. Skin scarification with Plasmodium falciparum peptide vaccine using synthetic TLR agonists as adjuvants elicits malaria sporozoite neutralizing immunity

    PubMed Central

    Mitchell, Robert A.; Altszuler, Rita; Frevert, Ute; Nardin, Elizabeth H.

    2016-01-01

    Malaria eradication will require a combination of vector control, chemotherapy and an easily administered vaccine. Sterile immunity can be elicited in humans by immunization with sporozoites, the infective stage injected by bite of the mosquito vector, however, whole parasite vaccines present formidable logistical challenges for production, storage and administration. The “gold standard” for infectious disease eradiation, the Smallpox Eradication Programme, utilized mass immunization using the skin scarification (SS) route. SS may more closely mimic the natural route of malaria infection initiated by sporozoites injected by mosquito bite which elicits both neutralizing antibodies and protective cell mediated immunity. We investigated the potential of SS immunization using a malaria repeat peptide containing a protective B cell epitope of Plasmodium falciparum, the most lethal human species, and delivery vehicles containing TLR agonists as adjuvants. In a murine model, SS immunization with peptide in combination with TLR-7/8 and -9 agonists elicited high levels of systemic sporozoite neutralizing antibody, Th1- type CD4+ T cells and resistance to challenge by bites of infected mosquitoes. SS provides the potential to elicit humoral immunity to target Plasmodium at multiple stages of its complex life cycle. PMID:27624667

  1. Skin scarification with Plasmodium falciparum peptide vaccine using synthetic TLR agonists as adjuvants elicits malaria sporozoite neutralizing immunity.

    PubMed

    Mitchell, Robert A; Altszuler, Rita; Frevert, Ute; Nardin, Elizabeth H

    2016-01-01

    Malaria eradication will require a combination of vector control, chemotherapy and an easily administered vaccine. Sterile immunity can be elicited in humans by immunization with sporozoites, the infective stage injected by bite of the mosquito vector, however, whole parasite vaccines present formidable logistical challenges for production, storage and administration. The "gold standard" for infectious disease eradiation, the Smallpox Eradication Programme, utilized mass immunization using the skin scarification (SS) route. SS may more closely mimic the natural route of malaria infection initiated by sporozoites injected by mosquito bite which elicits both neutralizing antibodies and protective cell mediated immunity. We investigated the potential of SS immunization using a malaria repeat peptide containing a protective B cell epitope of Plasmodium falciparum, the most lethal human species, and delivery vehicles containing TLR agonists as adjuvants. In a murine model, SS immunization with peptide in combination with TLR-7/8 and -9 agonists elicited high levels of systemic sporozoite neutralizing antibody, Th1- type CD4+ T cells and resistance to challenge by bites of infected mosquitoes. SS provides the potential to elicit humoral immunity to target Plasmodium at multiple stages of its complex life cycle. PMID:27624667

  2. Malaria parasite-inhibitory antibody epitopes on Plasmodium falciparum merozoite surface protein-1(19) mapped by TROSY NMR.

    PubMed

    Morgan, William D; Lock, Matthew J; Frenkiel, Thomas A; Grainger, Munira; Holder, Anthony A

    2004-11-01

    Plasmodium falciparum merozoite surface protein 1 (MSP1)(19), the C-terminal fragment of merozoite surface protein 1, is a leading candidate antigen for development of a vaccine against the blood stages of the malaria parasite. Many human and animal studies have indicated the importance of MSP1(19)-specific immune responses. Anti-MSP1(19) antibodies can prevent invasion of red blood cells by P. falciparum parasites in vitro. However, the fine specificity of anti-MSP1(19) antibodies is also important, as only a fraction of monoclonal antibodies (mAbs) have parasite-inhibitory activity in vitro. Human sera from malaria-endemic locations show strong MSP1(19) reactivity, but individual serum samples vary greatly in inhibitory activity. NMR is an excellent method for studying protein-protein interactions, and has been used widely to study binding of peptides representing known epitopes (as well as non-protein antigens) to antibodies and antibody fragments. The recent development of transverse relaxation optimized spectroscopy (TROSY) and related methods has significantly extended the maximum size limit of molecules that can be studied by NMR. TROSY NMR experiments produce high quality spectra of Fab complexes that allow the mapping of epitopes by the chemical shift perturbation technique on a complete, folded protein antigen such as MSP1(19). We studied the complexes of P. falciparum MSP1(19) with Fab fragments from three monoclonal antibodies. Two of these antibodies have parasite-inhibitory activity in vitro, while the third is non-inhibitory. NMR epitope mapping showed a close relationship between binding sites for the two inhibitory antibodies, distinct from the location of the non-inhibitory antibody. Together with a previously published crystal structure of the P. falciparum MSP1(19) complex with the Fab fragment of another non-inhibitory antibody, these results revealed a surface on MSP1(19) where inhibitory antibodies bind. This information will be useful in

  3. Population Pharmacokinetics of Pyronaridine in Pediatric Malaria Patients

    PubMed Central

    Ayyoub, Amal; Methaneethorn, Janthima; Ramharter, Michael; Djimde, Abdoulaye A.; Tekete, Mamadou; Duparc, Stephan; Borghini-Fuhrer, Isabelle; Shin, Jang-Sik

    2015-01-01

    Pyramax is a pyronaridine (PYR)-artesunate (PA) combination for the treatment of uncomplicated malaria in adult and pediatric patients. A granule formulation of this combination is being developed for treatment of uncomplicated P. falciparum and P. vivax malaria in pediatric patients. The aims of this study were to describe the pharmacokinetics of PYR using a total of 1,085 blood PYR concentrations available from 349 malaria patients younger than 16 years of age with mild to moderate uncomplicated malaria and to confirm the dosing regimen for the pediatric granule formulation. Nonlinear mixed-effects modeling using NONMEM software was used to obtain the pharmacokinetic and inter- and intraindividual variability parameter estimates. The population pharmacokinetics of PYR were described by a two-compartment model with first-order absorption and elimination. Allometric scaling was implemented to address the effect of body weight on clearance and volume parameters. The final parameter estimates of PYR apparent clearance (CL/F), central volume of distribution (V2/F), peripheral volume of distribution (V3/F), intercompartmental clearance (Q/F), and absorption rate constant (Ka) were 377 liters/day, 2,230 liters, 3,230 liters, 804 liters/day and 17.9 day−1, respectively. Covariate model building conducted using forward addition (P < 0.05) followed by backward elimination (P < 0.001) yielded two significant covariate-parameter relationships, i.e., age on V2/F and formulation on Ka. Evaluation of bootstrapping, visual predictive check, and condition number indicated that the final model displayed satisfactory robustness, predictive power, and stability. Simulations of PYR concentration-time profiles generated from the final model show similar exposures across pediatric weight ranges, supporting the proposed labeling for weight-based dosing of Pyramax granules. (These studies have been registered at ClinicalTrials.gov under registration no. NCT00331136 [phase II study] and

  4. Quantitative analysis of drug effects at the whole-body level: a case study for glucose metabolism in malaria patients.

    PubMed

    Snoep, Jacky L; Green, Kathleen; Eicher, Johann; Palm, Daniel C; Penkler, Gerald; du Toit, Francois; Walters, Nicolas; Burger, Robert; Westerhoff, Hans V; van Niekerk, David D

    2015-12-01

    We propose a hierarchical modelling approach to construct models for disease states at the whole-body level. Such models can simulate effects of drug-induced inhibition of reaction steps on the whole-body physiology. We illustrate the approach for glucose metabolism in malaria patients, by merging two detailed kinetic models for glucose metabolism in the parasite Plasmodium falciparum and the human red blood cell with a coarse-grained model for whole-body glucose metabolism. In addition we use a genome-scale metabolic model for the parasite to predict amino acid production profiles by the malaria parasite that can be used as a complex biomarker. PMID:26614654

  5. Longevity of Genotype-Specific Immune Responses to Plasmodium falciparum Merozoite Surface Protein 1 in Kenyan Children from Regions of Different Malaria Transmission Intensity.

    PubMed

    Bowman, Natalie M; Juliano, Jonathan J; Snider, Cynthia J; Kharabora, Oksana; Meshnick, Steven R; Vulule, John; John, Chandy C; Moormann, Ann M

    2016-09-01

    Naturally acquired immunity to Plasmodium falciparum presents a changing landscape as malaria control programs and vaccine initiatives are implemented. Determining which immunologic indicators remain surrogates of past infection, as opposed to mediators of protection, led us to compare stability of immune responses across regions with divergent malaria transmission intensities. A repeat cross-sectional study of Kenyan children from a malaria-holoendemic area and an epidemic-prone area was used to examine longitudinal antibody and interferon-gamma (IFN-γ) responses to the 3D7 and FVO variants of merozoite surface protein 1 (MSP1). Antibodies to MSP1 were common in both study populations and did not significantly wane over a 21-month time period. IFN-γ responses were less frequent and rapidly disappeared in children after a prolonged period of no malaria transmission. Antibody and IFN-γ responses rarely correlated with each other; however, MSP1-specific IFN-γ response correlated with lack of concurrent P. falciparum parasitemia of the same genotype, though only statistically significantly in the malaria-holoendemic region (odds ratio = 0.31, 95% confidence interval = 0.12-0.84). This study affirms that antimalarial antibodies are informative for evaluation of history of malaria exposure within individuals, whereas cell-mediated immunity, though short lived under natural exposure conditions, might provide an assessment of recent infection and protection from parasitemia. PMID:27481054

  6. Impact of age of first exposure to Plasmodium falciparum on antibody responses to malaria in children: a randomized, controlled trial in Mozambique

    PubMed Central

    2014-01-01

    Background The impact of the age of first Plasmodium falciparum infection on the rate of acquisition of immunity to malaria and on the immune correlates of protection has proven difficult to elucidate. A randomized, double-blind, placebo-controlled trial using monthly chemoprophylaxis with sulphadoxine-pyrimethamine plus artesunate was conducted to modify the age of first P. falciparum erythrocytic exposure in infancy and assess antibodies and malaria risk over two years. Methods Participants (n = 349) were enrolled at birth to one of three groups: late exposure, early exposure and control group, and were followed up for malaria morbidity and immunological analyses at birth, 2.5, 5.5, 10.5, 15 and 24 months of age. Total IgG, IgG subclasses and IgM responses to MSP-119, AMA-1, and EBA-175 were measured by ELISA, and IgG against variant antigens on the surface of infected erythrocytes by flow cytometry. Factors affecting antibody responses in relation to chemoprophylaxis and malaria incidence were evaluated. Results Generally, antibody responses did not vary significantly between exposure groups except for levels of IgM to EBA-175, and seropositivity of IgG1 and IgG3 to MSP-119. Previous and current malaria infections were strongly associated with increased IgG against MSP-119, EBA-175 and AMA-1 (p < 0.0001). After adjusting for exposure, only higher levels of anti-EBA-175 IgG were significantly associated with reduced clinical malaria incidence (IRR 0.67, p = 0.0178). Conclusions Overall, the age of first P. falciparum infection did not influence the magnitude and breadth of IgG responses, but previous exposure was critical for antibody acquisition. IgG responses to EBA-175 were the strongest correlate of protection against clinical malaria. Trial registration ClinicalTrials.gov: NCT00231452. PMID:24674654

  7. Therapeutic efficacy of sulfadoxine-pyrimethamine, amodiaquine and the sulfadoxine-pyrimethamine-amodiaquine combination against uncomplicated Plasmodium falciparum malaria in young children in Cameroon.

    PubMed Central

    Basco, Leonardo K.; Same-Ekobo, Albert; Ngane, Vincent Foumane; Ndounga, Mathieu; Metoh, Theresia; Ringwald, Pascal; Soula, Georges

    2002-01-01

    OBJECTIVE: To evaluate the therapeutic efficacy of sulfadoxine-pyrimethamine, amodiaquine, and the sulfadoxine-pyrimethamine-amodiaquine combination for the treatment of uncomplicated Plasmodium falciparum malaria in young children in Cameroon. METHODS: In a randomized study we evaluated the effectiveness and tolerance of (i) sulfadoxine-pyrimethamine (SP) (25 mg/kg body weight of sulfadoxine and 1.25 mg/kg of pyrimethamine in a single oral dose), (ii) amodiaquine (AQ) (30 mg/kg body weight in three divided daily doses), and (iii) the sulfadoxine-pyrimethamine-amodiaquine combination (SP+AQ) (same doses as in the other two treatment groups, given simultaneously on day 0) in young children in southern Cameroon. The parasitological and clinical responses were studied until day 28 in accordance with the modified 1996 WHO protocol for the evaluation of the therapeutic efficacy of antimalarial drugs. FINDINGS: Of 191 enrolled patients, 6 and 8 were excluded or lost to follow-up before day 14 and between day 14 and day 28, respectively. For the AQ-treated patients, parasitological and clinical evaluation on day 14 showed late treatment failure in 2 of 61 (3.3%) and adequate clinical response with parasitological failure in one (1.6%). There was an adequate clinical response in all patients treated with SP or SP+AQ. Therapeutic failure rates on day 28 were 13.6%, 10.2% and 0% in the SP, AQ, and SP+AQ groups, respectively. Anaemia improved in all three regimens. AQ produced faster fever clearance but was associated with more transient minor side-effects than SP. SP+AQ reduced the risk of recrudescence between day 14 and day 28 but increased the incidence of minor side-effects. CONCLUSION: SP+AQ can be recommended as a temporary means of slowing the spread of multidrug resistance in Plasmodium falciparum in Africa while the introduction of other combinations, including artemisinin derivatives, is awaited. PMID:12163917

  8. Adaptive evolution and fixation of drug-resistant Plasmodium falciparum genotypes in pregnancy-associated malaria: 9-year results from the QuEERPAM study

    PubMed Central

    Taylor, Steve M; Antonia, Alejandro; Feng, Gaoqian; Mwapasa, Victor; Chaluluka, Ebbie; Molyneux, Malcolm; Kuile, Feiko O ter; Rogerson, Stephen J; Meshnick, Steven R

    2011-01-01

    Sulfadoxine-pyrimethamine (SP) has been widely deployed in Africa for malaria control and molecular evidence of parasite drug-resistance is prevalent. However, the temporal effects on the selection of Plasmodium falciparum are not well understood. We conducted a retrospective serial cross-sectional study between 1997 and 2006 to investigate changes in drug-resistant malaria among pregnant women delivering at a single hospital in Blantyre, Malawi. P. falciparum parasites were genotyped for parasite clone multiplicity and drug-resistance mutations, and the strength of selection upon mutant genotypes was quantified. Five mutations in the dihydrofolate reductase and dihydropteroate synthase genes began at moderate frequencies and achieved fixation by 2005; the frequency of the highly-SP-resistant “quintuple mutant” haplotype increased from 19% to 100%. The selective advantage of alleles and haplotypes were quantified with selection coefficients: Selection was positive on all mutant alleles and haplotypes associated with SP resistance, and the relative fitness of the quintuple mutant haplotype was 0.139 (95% C.I. 0.067 – 0.211), indicating a substantial positive selective advantage. Mutations that confer higher levels of resistance to SP did not emerge. SP-resistant haplotypes were rapidly selected for and fixed in P. falciparum populations infecting pregnant women while SP was widely deployed in Malawi. These results underscore the pressing need for new preventive measures for pregnancy-associated malaria and provide a real-world model of the selection landscape malaria parasites. PMID:22119749

  9. Discovery of a new family of carbonic anhydrases in the malaria pathogen Plasmodium falciparum--the η-carbonic anhydrases.

    PubMed

    Del Prete, Sonia; Vullo, Daniela; Fisher, Gillian M; Andrews, Katherine T; Poulsen, Sally-Ann; Capasso, Clemente; Supuran, Claudiu T

    2014-09-15

    The genome of the protozoan parasite Plasmodium falciparum, the causative agent of the most lethal type of human malaria, contains a single gene annotated as encoding a carbonic anhydrase (CAs, EC 4.2.1.1) thought to belong to the α-class, PfCA. Here we demonstrate the kinetic properties of PfCA for the CO2 hydration reaction, as well as an inhibition study of this enzyme with inorganic and complex anions and other molecules known to interact with zinc proteins, including sulfamide, sulfamic acid, and phenylboronic/arsonic acids, detecting several low micromolar inhibitors. A closer examination of the sequence of this and the CAs from other Plasmodium spp., as well as a phylogenetic analysis, revealed that these protozoa encode for a yet undisclosed, new genetic family of CAs termed the η-CA class. The main features of the η-CAs are described in this report. PMID:25168745

  10. Absence of the human CYP2C8*3 allele in Ugandan children exposed to Plasmodium falciparum malaria.

    PubMed

    Paganotti, Giacomo Maria; Cosentino, Valentina; Russo, Gianluca; Tabacchi, Francesca; Gramolelli, Silvia; Coluzzi, Mario; Romano, Rita

    2014-10-01

    Study of host pharmacogenetics can improve our knowledge of mechanisms of drug resistance selection and spread. This issue has recently been addressed with respect to chloroquine and amodiaquine in malaria endemic areas of West and East Africa. Here we report, from surveys performed in two different areas of Uganda, that the human CYP2C8*3 allele, which had been reported to be strongly associated with parasite drug resistance in Zanzibar, is absent, being a marker of genetic admixture of the Zanzibari population with a Caucasoid component. Moreover, a retrospective analysis of CYP2C8*2 and the Plasmodium falciparum drug resistant pfmdr1 86Y allele does not show any association, which may be related to the high level of drug resistance.

  11. Performance of Interferon-Gamma and IP-10 Release Assays for Diagnosing Latent Tuberculosis Infections in Patients with Concurrent Malaria in Tanzania.

    PubMed

    Drabe, Camilla H; Vestergaard, Lasse S; Helleberg, Marie; Nyagonde, Nyagonde; Rose, Michala V; Francis, Filbert; Theilgaard, Ola P; Asbjørn, Jens; Amos, Ben; Bygbjerg, Ib Christian; Ruhwald, Morten; Ravn, Pernille

    2016-04-01

    Interferon-gamma (IFN-γ) release assays (IGRAs) are used to detect cellular immune recognition of Mycobacterium tuberculosis The chemokine IFN-γ-inducible protein 10 (IP-10) is an alternative diagnostic biomarker to IFN-γ. Several conditions interfere with IGRA test performance. We aimed to assess the possible influence of Plasmodium falciparum infection on the IGRA test QuantiFERON-TB GOLD® In-Tube (QFT) test and an in-house IP-10 release assay. In total, 241 Tanzanian adults were included; 184 patients with uncomplicated malaria (88 human immunodeficiency virus [HIV] coinfected) and 57 HIV-infected patients without malaria infection. Malaria was treated with artemether-lumefantrine (Coartem®). QFT testing was performed before initiation of malaria treatment and at days 7 and 42. In total, 172 patients completed follow-up. IFN-γ and IP-10 was measured in QFT supernatants. We found that during malaria infection IFN-γ and IP-10 levels in the unstimulated samples were elevated, mitogen responsiveness was impaired, and CD4 cell counts were decreased. These alterations reverted after malaria treatment. Concurrent malaria infection did not affect QFT test results, whereas there were more indeterminate IP-10 results during acute malaria infection. We suggest that IGRA and IP-10 release assay results of malaria patients should be interpreted with caution and that testing preferably should be postponed until after malaria treatment.

  12. Iron Deficiency Protects Against Severe Plasmodium falciparum Malaria and Death in Young Children

    PubMed Central

    Gwamaka, Moses; Kurtis, Jonathan D.; Sorensen, Bess E.; Holte, Sarah; Morrison, Robert; Mutabingwa, Theonest K.; Fried, Michal

    2012-01-01

    (See the Editorial Commentary by Awah and Kaneko, on pages 1145–7.) Background. Iron supplementation may increase malaria morbidity and mortality, but the effect of naturally occurring variation in iron status on malaria risk is not well studied. Methods. A total of 785 Tanzanian children living in an area of intense malaria transmission were enrolled at birth, and intensively monitored for parasitemia and illness including malaria for up to 3 years, with an average of 47 blood smears. We assayed plasma samples collected at routine healthy-child visits, and evaluated the impact of iron deficiency (ID) on future malaria outcomes and mortality. Results. ID at routine, well-child visits significantly decreased the odds of subsequent parasitemia (23% decrease, P < .001) and subsequent severe malaria (38% decrease, P = .04). ID was also associated with 60% lower all-cause mortality (P = .04) and 66% lower malaria-associated mortality (P = .11). When sick visits as well as routine healthy-child visits are included in analyses (average of 3 iron status assays/child), ID reduced the prevalence of parasitemia (6.6-fold), hyperparasitemia (24.0-fold), and severe malaria (4.0-fold) at the time of sample collection (all P < .001). Conclusions. Malaria risk is influenced by physiologic iron status, and therefore iron supplementation may have adverse effects even among children with ID. Future interventional studies should assess whether treatment for ID coupled with effective malaria control can mitigate the risks of iron supplementation for children in areas of malaria transmission. PMID:22354919

  13. 3D nuclear architecture reveals coupled cell cycle dynamics of chromatin and nuclear pores in the malaria parasite Plasmodium falciparum.

    PubMed

    Weiner, Allon; Dahan-Pasternak, Noa; Shimoni, Eyal; Shinder, Vera; von Huth, Palle; Elbaum, Michael; Dzikowski, Ron

    2011-07-01

    The deadliest form of human malaria is caused by the protozoan parasite Plasmodium falciparum. The complex life cycle of this parasite is associated with tight transcriptional regulation of gene expression. Nuclear positioning and chromatin dynamics may play an important role in regulating P. falciparum virulence genes. We have applied an emerging technique of electron microscopy to construct a 3D model of the parasite nucleus at distinct stages of development within the infected red blood cell. We have followed the distribution of nuclear pores and chromatin throughout the intra-erythrocytic cycle, and have found a striking coupling between the distributions of nuclear pores and chromatin organization. Pore dynamics involve clustering, biogenesis, and division among daughter cells, while chromatin undergoes stage-dependent changes in packaging. Dramatic changes in heterochromatin distribution coincide with a previously identified transition in gene expression and nucleosome positioning during the mid-to-late schizont phase. We also found a correlation between euchromatin positioning at the nuclear envelope and the local distribution of nuclear pores, as well as a dynamic nuclear polarity during schizogony. These results suggest that cyclic patterns in gene expression during parasite development correlate with gross changes in cellular and nuclear architecture.

  14. Expression of senescent antigen on erythrocytes infected with a knobby variant of the human malaria parasite Plasmodium falciparum

    SciTech Connect

    Winograd, E.; Greenan, J.R.T.; Sherman, I.W.

    1987-04-01

    Erythrocytes infected with a knobby variant of Plasmodium falciparum selectively bind IgG autoantibodies in normal human serum. Quantification of membrane-bound IgG, by use of /sup 125/I-labeled protein A, revealed that erythrocytes infected with the knobby variant bound 30 times more protein A than did noninfected erythrocytes; infection with a knobless variant resulted in less than a 2-fold difference compared with noninfected erythrocytes. IgG binding to knobby erythrocytes appeared to be related to parasite development, since binding of /sup 125/I-labeled protein A to cells bearing young trophozoites (less than 20 hr after parasite invasion) was similar to binding to uninfected erythrocytes. By immunoelectron microscopy, the membrane-bound IgG on erythrocytes infected with the knobby variant was found to be preferentially associated with the protuberances (knobs) of the plasma membrane. The removal of aged or senescent erythrocytes from the peripheral circulation is reported to involve the binding of specific antibodies to an antigen (senescent antigen) related to the major erythrocyte membrane protein band 3. Since affinity-purified autoantibodies against band 3 specifically bound to the plasma membrane of erythrocytes infected with the knobby variant of P. falciparum, it is clear that the malaria parasite induces expression of senescent antigen.

  15. Predictors of the failure of treatment with chloroquine plus chlorpheniramine, in children with acute, uncomplicated, Plasmodium falciparum malaria.

    PubMed

    Sowunmi, A; Fateye, B A; Adedeji, A A; Fehintola, F A; Gbotosho, G O; Happi, T C; Oduola, A M J

    2005-06-01

    Resistance to chloroquine in Plasmodium falciparum can be reversed, both in vitro and in vivo, by chlorpheniramine, a histamine H(1) receptor antagonist. This reversal raises the possibility of using chlorpheniramine to prolong the clinical usefulness of chloroquine in resource-poor communities. The factors that identify children at risk of treatment failure after being given chloroquine plus chlorpheniramine have now been evaluated in 281 children with uncomplicated, P. falciparum malaria. The children, who had taken part in six trials of antimalarial drugs between February 1996 and September 1999, in a hyper-endemic area of south-western Nigeria, were enrolled prospectively for the present study. Following treatment with chloroquine plus chlorpheniramine, 13 (5%) of the children failed treatment by day 7 or 14. In a multivariate analysis, an age of < or =3 years (adjusted odds ratio = 11.1; 95% confidence interval = 2.2-55.3; P = 0.003) and a parasitaemia that took >3 days to clear (adjusted odds ratio=7.9; 95% confidence interval = 1.3-49.4; P = 0.027) were found to be independent predictors of treatment failure. In addition, compared with the children who had a lower axillary temperature then, the children who had an axillary temperature of > or =38 degrees C 2 days after commencing treatment were significantly more likely to be treatment failures. In resource-poor communities using chloroquine plus chlorpheniramine, the easily identifiable predictors of treatment failure might be used to identify children requiring alternative antimalarial drugs.

  16. The treatment of malaria.

    PubMed

    White, N J

    1996-09-12

    Increasing drug resistance in Plasmodium falciparum and a resurgence of malaria in tropical areas have effected a change in treatment of malaria in the last two decades. Symptoms of malaria are fever, chills, headache, and malaise. The prognosis worsens as the parasite counts, counts of mature parasites, and counts of neutrophils containing pigment increase. Treatment depends on severity, age of patient, degree of background immunity, likely pattern of susceptibility to antimalarial drugs, and the cost and availability of drugs. Chloroquine should be used for P. vivax, P. malariae, and P. ovale. P. vivax has shown high resistance to chloroquine in Oceania, however. Primaquine may be needed to treat P. vivax and P. ovale to rid the body of hypnozoites that survive in the liver. Chloroquine can treat P. falciparum infections acquired in North Africa, Central America north of the Panama Canal, Haiti, or the Middle East but not in most of Africa and some parts of Asia and South America. In areas of low grade resistance to chloroquine, amodiaquine can be used to effectively treat falciparum malaria. A combination of sulfadoxine-pyrimethamine is responsive to falciparum infections with high grade resistance to chloroquine. Mefloquine, halofantrine, or quinine with tetracycline can be used to treat multidrug-resistant P. falciparum. Derivatives of artemisinin obtained from qinghao or sweet wormwood developed as pharmaceuticals in China are the most rapidly acting of all antimalarial drugs. Children tend to tolerate antimalarial drugs well. Children who weigh less than 15 kg should not be given mefloquine. Health workers should not prescribe primaquine to pregnant women or newborns due to the risk of hemolysis. Chloroquine, sulfadoxine-pyrimethamine, quinine, and quinidine can be safely given in therapeutic doses throughout pregnancy. Clinical manifestations of severe malaria are hypoglycemia, convulsions, severe anemia, acute renal failure, jaundice, pulmonary edema

  17. Efficacy of a Novel Sublingual Spray Formulation of Artemether in African Children with Plasmodium falciparum Malaria

    PubMed Central

    Rulisa, Stephen; Ansah, Patrick; Sirima, Sodiomon

    2015-01-01

    The efficacy of sublingual artemether (ArTiMist) was investigated in two studies. In study 1, 31 children were randomized to sublingual artemether (n = 16) or intravenous (i.v.) quinine (n = 15). In study 2, 151 children were randomized to sublingual artemether (n = 77) or i.v. quinine (n = 74). For both studies, patients weighed between 5 and 15 kg and had either severe or complicated malaria based on WHO criteria, or they had uncomplicated malaria but were unable to tolerate oral medication as a result of nausea, vomiting, or diarrhea. Patients received either 3 mg/kg of body weight of sublingual artemether or a loading dose of 20 mg/kg of i.v. quinine followed by 10 mg/kg every 8 h i.v. thereafter. The primary endpoint was parasitological success, defined as a reduction in parasite count of ≥90% of that at baseline at 24 h after the first dose. Other endpoints based on parasite clearance and clinical response were evaluated. In study 1, there were parasitological success rates of 93.3% (14/15) and 66.7% (10/15) for the sublingual artemether and quinine treatments, respectively. In study 2, 94.3% (66/70) of the ArTiMist-treated patients and 39.4% (28/71) of the quinine-treated patients had parasitological success (P < 0.0001). Indicators of parasite clearance (parasite clearance time [PCT], time for parasite count to fall by 50% [PCT50], time for parasite count to fall by 90% [PCT90], and percent reduction in parasitemia from baseline at 24 h [PRR24]) were significantly superior for children treated with sublingual artemether compared to those treated with i.v. quinine. There were no differences between treatments for the clinical endpoints, such as fever clearance time. The local tolerability of sublingual artemether was good. Sublingual artemether leads to rapid parasite clearance and clinical recovery. (Studies 1 and 2 are registered at ClinicalTrials.gov under registration numbers NCT01047436 and NCT01258049, respectively.) PMID:26303805

  18. Detection of Plasmodium vivax and Plasmodium falciparum DNA in human saliva and urine: loop-mediated isothermal amplification for malaria diagnosis.

    PubMed

    Ghayour Najafabadi, Zahra; Oormazdi, Hormozd; Akhlaghi, Lame; Meamar, Ahmad Reza; Nateghpour, Mehdi; Farivar, Leila; Razmjou, Elham

    2014-08-01

    This study investigated loop-mediated isothermal amplification (LAMP) detection of Plasmodium falciparum and Plasmodium vivax in urine and saliva of malaria patients. From May to November 2011, 108 febrile patients referred to health centers in Sistan and Baluchestan Province of south-eastern Iran participated in the study. Saliva, urine, and blood samples were analyzed with nested PCR and LAMP targeting the species-specific nucleotide sequence of small subunit ribosomal RNA gene (18S rRNA) of P. falciparum and P. vivax and evaluated for diagnostic accuracy by comparison to blood nested PCR assay. When nested PCR of blood is used as standard, microscopy and nested PCR of saliva and urine samples showed sensitivity of 97.2%, 89.4% and 71% and specificity of 100%, 97.3% and 100%, respectively. LAMP sensitivity of blood, saliva, and urine was 95.8%, 47% and 29%, respectively, whereas LAMP specificity of these samples was 100%. Microscopy and nested PCR of saliva and LAMP of blood were comparable to nested PCR of blood (к=0.95, 0.83, and 0.94, respectively), but agreement for nested PCR of urine was moderate (к=0.64) and poor to fair for saliva LAMP and urine LAMP (к=0.38 and 0.23, respectively). LAMP assay showed low sensitivity for detection of Plasmodium DNA in human saliva and urine compared to results with blood and to nested PCR of blood, saliva, and urine. However, considering the advantages of LAMP technology and of saliva and urine sampling, further research into the method is worthwhile. LAMP protocol and precise preparation protocols need to be defined and optimized for template DNA of saliva and urine.

  19. Greater endothelial activation, Weibel-Palade body release and host inflammatory response to Plasmodium vivax, compared with Plasmodium falciparum: a prospective study in Papua, Indonesia.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Tjitra, Emiliana; Piera, Kim; Gitawati, Retno; Kenangalem, Enny; Price, Ric N; Anstey, Nicholas M

    2010-07-01

    Pathogenic mechanisms underlying vivax malaria are poorly understood, with few studies comparing endothelial and inflammatory responses with falciparum malaria. In adults with uncomplicated vivax or falciparum malaria, we compared plasma measurements of endothelial Weibel-Palade body release (angiopoietin-2) and activation (ICAM-1, E-selectin), as well as selected cytokines. Despite a lower median parasite count, angiopoietin-2 concentrations were higher in patients with vivax malaria, compared with falciparum malaria. Per peripheral parasite, median plasma angiopoietin-2, ICAM-1, E-selectin, interleukin-6, and interleukin-10 concentrations were higher in patients with malaria due to Plasmodium vivax. P. vivax induces greater endothelial Weibel-Palade body release and activation and greater host inflammatory responses, compared with Plasmodium falciparum.

  20. Novel phenotypic assays for the detection of artemisinin-resistant Plasmodium falciparum malaria in Cambodia: in-vitro and ex-vivo drug-response studies

    PubMed Central

    Witkowski, Benoit; Amaratunga, Chanaki; Khim, Nimol; Sreng, Sokunthea; Chim, Pheaktra; Kim, Saorin; Lim, Pharath; Mao, Sivanna; Sopha, Chantha; Sam, Baramey; Anderson, Jennifer M; Duong, Socheat; Chuor, Char Meng; Taylor, Walter R J; Suon, Seila; Mercereau-Puijalon, Odile; Fairhurst, Rick M; Menard, Didier

    2016-01-01

    Summary Background Artemisinin resistance in Plasmodium falciparum lengthens parasite clearance half-life during artemisinin monotherapy or artemisinin-based combination therapy. Absence of in-vitro and ex-vivo correlates of artemisinin resistance hinders study of this phenotype. We aimed to assess whether an in-vitro ring-stage survival assay (RSA) can identify culture-adapted P falciparum isolates from patients with slow-clearing or fast-clearing infections, to investigate the stage-dependent susceptibility of parasites to dihydroartemisinin in the in-vitro RSA, and to assess whether an ex-vivo RSA can identify artemisinin-resistant P falciparum infections. Methods We culture-adapted parasites from patients with long and short parasite clearance half-lives from a study done in Pursat, Cambodia, in 2010 (registered with ClinicalTrials.gov, number NCT00341003) and used novel in-vitro survival assays to explore the stage-dependent susceptibility of slow-clearing and fast-clearing parasites to dihydroartemisinin. In 2012, we implemented the RSA in prospective parasite clearance studies in Pursat, Preah Vihear, and Ratanakiri, Cambodia (NCT01736319), to measure the ex-vivo responses of parasites from patients with malaria. Continuous variables were compared with the Mann-Whitney U test. Correlations were analysed with the Spearman correlation test. Findings In-vitro survival rates of culture-adapted parasites from 13 slow-clearing and 13 fast-clearing infections differed significantly when assays were done on 0–3 h ring-stage parasites (10·88% vs 0·23%; p=0·007). Ex-vivo survival rates significantly correlated with in-vivo parasite clearance half-lives (n=30, r=0·74, 95% CI 0·50–0·87; p<0·0001). Interpretation The in-vitro RSA of 0–3 h ring-stage parasites provides a platform for the molecular characterisation of artemisinin resistance. The ex-vivo RSA can be easily implemented where surveillance for artemisinin resistance is needed. Funding Institut

  1. Differential Recognition of Terminal Extracellular Plasmodium falciparum VAR2CSA Domains by Sera from Multigravid, Malaria-Exposed Malian Women

    PubMed Central

    Travassos, Mark A.; Coulibaly, Drissa; Bailey, Jason A.; Niangaly, Amadou; Adams, Matthew; Nyunt, Myaing M.; Ouattara, Amed; Lyke, Kirsten E.; Laurens, Matthew B.; Pablo, Jozelyn; Jasinskas, Algis; Nakajima, Rie; Berry, Andrea A.; Takala-Harrison, Shannon; Kone, Abdoulaye K.; Kouriba, Bourema; Rowe, J. Alexandra; Doumbo, Ogobara K.; Thera, Mahamadou A.; Laufer, Miriam K.; Felgner, Philip L.; Plowe, Christopher V.

    2015-01-01

    The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family mediates parasite sequestration in small capillaries through tissue-specific cytoadherence. The best characterized of these proteins is VAR2CSA, which is expressed on the surface of infected erythrocytes that bind to chondroitin sulfate in the placental matrix. Antibodies to VAR2CSA prevent placental cytoadherence and protect against placental malaria. The size and complexity of the VAR2CSA protein pose challenges for vaccine development, but smaller constitutive domains may be suitable for subunit vaccine development. A protein microarray was printed to include five overlapping fragments of the 3D7 VAR2CSA extracellular region. Malian women with a history of at least one pregnancy had antibody recognition of four of these fragments and had stronger reactivity against the two distal fragments than did nulliparous women, children, and men from Mali, suggesting that the C-terminal extracellular VAR2CSA domains are a potential focus of protective immunity. With carefully chosen sera from longitudinal studies of pregnant women, this approach has the potential to identify seroreactive VAR2CSA domains associated with protective immunity against pregnancy-associated malaria. PMID:25918203

  2. Efficacy of Artemisinin-Based Combination Treatments of Uncomplicated Falciparum Malaria in Under-Five-Year-Old Nigerian Children

    PubMed Central

    Oguche, Stephen; Okafor, Henrietta U.; Watila, Ismaila; Meremikwu, Martin; Agomo, Philip; Ogala, William; Agomo, Chimere; Ntadom, Godwin; Banjo, Olajide; Okuboyejo, Titilope; Ogunrinde, Gboye; Odey, Friday; Aina, Olugbemiga; Sofola, Tolulope; Sowunmi, Akintunde

    2014-01-01

    The efficacy of 3-day regimens of artemether-lumefantrine and artesunate-amodiaquine were evaluated in 747 children < 5 years of age with uncomplicated malaria from six geographical areas of Nigeria. Fever clearance was significantly faster (P = 0.006) and the proportion of children with parasitemia 1 day after treatment began was significantly lower (P = 0.016) in artesunate-amodiaquine—compared with artemether-lumefantrine-treated children. Parasite clearance times were similar with both treatments. Overall efficacy was 96.3% (95% confidence interval [CI] 94.5–97.6%), and was similar for both regimens. Polymerase chain reaction-corrected parasitologic cure rates on Day 28 were 96.9% (95% CI 93.9–98.2%) and 98.3% (95% CI 96.1–99.3%) for artemether-lumefantrine and artesunate-amodiaquine, respectively. Gametocyte carriage post treatment was significantly lower than pretreatment (P < 0.0001). In anemic children, mean time to recovery from anemia was 10 days (95% CI 9.04–10.9) and was similar for both regimens. Both treatments were well tolerated and are safe and efficacious treatments of uncomplicated falciparum malaria in young Nigerian children. PMID:25246693

  3. A genetically attenuated malaria vaccine candidate based on P. falciparum b9/slarp gene-deficient sporozoites.

    PubMed

    van Schaijk, Ben C L; Ploemen, Ivo H J; Annoura, Takeshi; Vos, Martijn W; Foquet, Lander; van Gemert, Geert-Jan; Chevalley-Maurel, Severine; van de Vegte-Bolmer, Marga; Sajid, Mohammed; Franetich, Jean-Francois; Lorthiois, Audrey; Leroux-Roels, Geert; Meuleman, Philip; Hermsen, Cornelius C; Mazier, Dominique; Hoffman, Stephen L; Janse, Chris J; Khan, Shahid M; Sauerwein, Robert W

    2014-01-01

    A highly efficacious pre-erythrocytic stage vaccine would be an important tool for the control and elimination of malaria but is currently unavailable. High-level protection in humans can be achieved by experimental immunization with Plasmodium falciparum sporozoites attenuated by radiation or under anti-malarial drug coverage. Immunization with genetically attenuated parasites (GAP) would be an attractive alternative approach. In this study, we present data on safety and protective efficacy using sporozoites with deletions of two genes, that is the newly identified b9 and slarp, which govern independent and critical processes for successful liver-stage development. In the rodent malaria model, PbΔb9ΔslarpGAP was completely attenuated showing no breakthrough infections while efficiently inducing high-level protection. The human PfΔb9ΔslarpGAP generated without drug resistance markers were infective to human hepatocytes in vitro and to humanized mice engrafted with human hepatocytes in vivo but completely aborted development after infection. These findings support the clinical development of a PfΔb9ΔslarpSPZ vaccine. PMID:25407681

  4. Efficacy of artemisinin-based combination treatments of uncomplicated falciparum malaria in under-five-year-old Nigerian children.

    PubMed

    Oguche, Stephen; Okafor, Henrietta U; Watila, Ismaila; Meremikwu, Martin; Agomo, Philip; Ogala, William; Agomo, Chimere; Ntadom, Godwin; Banjo, Olajide; Okuboyejo, Titilope; Ogunrinde, Gboye; Odey, Friday; Aina, Olugbemiga; Sofola, Tolulope; Sowunmi, Akintunde

    2014-11-01

    The efficacy of 3-day regimens of artemether-lumefantrine and artesunate-amodiaquine were evaluated in 747 children < 5 years of age with uncomplicated malaria from six geographical areas of Nigeria. Fever clearance was significantly faster (P = 0.006) and the proportion of children with parasitemia 1 day after treatment began was significantly lower (P = 0.016) in artesunate-amodiaquine-compared with artemether-lumefantrine-treated children. Parasite clearance times were similar with both treatments. Overall efficacy was 96.3% (95% confidence interval [CI] 94.5-97.6%), and was similar for both regimens. Polymerase chain reaction-corrected parasitologic cure rates on Day 28 were 96.9% (95% CI 93.9-98.2%) and 98.3% (95% CI 96.1-99.3%) for artemether-lumefantrine and artesunate-amodiaquine, respectively. Gametocyte carriage post treatment was significantly lower than pretreatment (P < 0.0001). In anemic children, mean time to recovery from anemia was 10 days (95% CI 9.04-10.9) and was similar for both regimens. Both treatments were well tolerated and are safe and efficacious treatments of uncomplicated falciparum malaria in young Nigerian children.

  5. Nanoparticle-Based Histidine-Rich Protein-2 Assay for the Detection of the Malaria Parasite Plasmodium falciparum.

    PubMed

    Castro-Sesquen, Yagahira E; Kim, Chloe; Gilman, Robert H; Sullivan, David J; Searson, Peter C

    2016-08-01

    A nanoparticle-based assay for detection and quantification of Plasmodium falciparum histidine-rich protein 2 (HRP2) in urine and serum is reported. The assay uses magnetic beads conjugated with anti-HRP2 antibody for protein capture and concentration, and antibody-conjugated quantum dots for optical detection. Western blot analysis demonstrated that magnetic beads allow the concentration of HRP2 protein in urine by 20-fold. The concentration effect was achieved because large volume of urine can be incubated with beads, and magnetic separation can be easily performed in minutes to isolate beads containing HRP2 protein. Magnetic beads and quantum dots conjugated to anti-HRP2 antibodies allows the detection of low concentrations of HRP2 protein (0.5 ng/mL), and quantification in the range of 33-2,000 ng/mL corresponding to the range associated with non-severe to severe malaria. This assay can be easily adapted to a noninvasive point-of-care test for classification of severe malaria.

  6. A genetically attenuated malaria vaccine candidate based on P. falciparum b9/slarp gene-deficient sporozoites

    PubMed Central

    van Schaijk, Ben C L; Ploemen, Ivo H J; Annoura, Takeshi; Vos, Martijn W; Foquet, Lander; van Gemert, Geert-Jan; Chevalley-Maurel, Severine; van de Vegte-Bolmer, Marga; Sajid, Mohammed; Franetich, Jean-Francois; Lorthiois, Audrey; Leroux-Roels, Geert; Meuleman, Philip; Hermsen, Cornelius C; Mazier, Dominique; Hoffman, Stephen L; Janse, Chris J; Khan, Shahid M; Sauerwein, Robert W

    2014-01-01

    A highly efficacious pre-erythrocytic stage vaccine would be an important tool for the control and elimination of malaria but is currently unavailable. High-level protection in humans can be achieved by experimental immunization with Plasmodium falciparum sporozoites attenuated by radiation or under anti-malarial drug coverage. Immunization with genetically attenuated parasites (GAP) would be an attractive alternative approach. In this study, we present data on safety and protective efficacy using sporozoites with deletions of two genes, that is the newly identified b9 and slarp, which govern independent and critical processes for successful liver-stage development. In the rodent malaria model, PbΔb9ΔslarpGAP was completely attenuated showing no breakthrough infections while efficiently inducing high-level protection. The human PfΔb9ΔslarpGAP generated without drug resistance markers were infective to human hepatocytes in vitro and to humanized mice engrafted with human hepatocytes in vivo but completely aborted development after infection. These findings support the clinical development of a PfΔb9ΔslarpSPZ vaccine. DOI: http://dx.doi.org/10.7554/eLife.03582.001 PMID:25407681

  7. Chemokines responses to Plasmodium falciparum malaria and co-infections among rural Cameroonians.

    PubMed

    Che, Jane Nchangnwi; Nmorsi, Onyebiguwa Patrick Goddey; Nkot, Baleguel Pierre; Isaac, Clement; Okonkwo, Browne Chukwudi

    2015-04-01

    Malaria remains the major cause of disease morbidity and mortality in sub-Saharan Africa with complex immune responses associated with disease outcomes. Symptoms associated with severe malaria have generally shown chemokine upregulation but little is known of responses to uncomplicated malaria. Eight villages in central Cameroon of 1045 volunteers were screened. Among these, malaria-positive individuals with some healthy controls were selected for chemokine analysis using Enzyme-Linked Immunosorbent Assay (ELISA) kits. Depressed serum levels of CXCL5 and raised CCL28 were observed in malarial positives when compared with healthy controls. The mean concentration of CXCL11 was higher in symptomatic than asymptomatic group, while CCL28 was lower in symptomatic individuals. Lower chemokine levels were associated with symptoms of uncomplicated malaria except for CXCL11 which was upregulated among fever-positive group. The mean CXCL5 level was higher in malaria sole infection than co-infections with HIV and Loa loa. Also, there was a raised mean level of malaria+HIV co-infection for CXCL9. This study hypothesises a situation where depressed chemokines in the face of clinical presentations could indicate an attempt by the immune system in preventing a progression process from uncomplicated to complicated outcomes with CXCL11 being identified as possible biomarker for malarial fever. PMID:25462711

  8. Chemokines responses to Plasmodium falciparum malaria and co-infections among rural Cameroonians.

    PubMed

    Che, Jane Nchangnwi; Nmorsi, Onyebiguwa Patrick Goddey; Nkot, Baleguel Pierre; Isaac, Clement; Okonkwo, Browne Chukwudi

    2015-04-01

    Malaria remains the major cause of disease morbidity and mortality in sub-Saharan Africa with complex immune responses associated with disease outcomes. Symptoms associated with severe malaria have generally shown chemokine upregulation but little is known of responses to uncomplicated malaria. Eight villages in central Cameroon of 1045 volunteers were screened. Among these, malaria-positive individuals with some healthy controls were selected for chemokine analysis using Enzyme-Linked Immunosorbent Assay (ELISA) kits. Depressed serum levels of CXCL5 and raised CCL28 were observed in malarial positives when compared with healthy controls. The mean concentration of CXCL11 was higher in symptomatic than asymptomatic group, while CCL28 was lower in symptomatic individuals. Lower chemokine levels were associated with symptoms of uncomplicated malaria except for CXCL11 which was upregulated among fever-positive group. The mean CXCL5 level was higher in malaria sole infection than co-infections with HIV and Loa loa. Also, there was a raised mean level of malaria+HIV co-infection for CXCL9. This study hypothesises a situation where depressed chemokines in the face of clinical presentations could indicate an attempt by the immune system in preventing a progression process from uncomplicated to complicated outcomes with CXCL11 being identified as possible biomarker for malarial fever.

  9. A cross strain Plasmodium falciparum microarray optimized for the transcriptome analysis of Plasmodium falciparum patient derived isolates.

    PubMed

    Subudhi, Amit Kumar; Boopathi, P A; Middha, Sheetal; Acharya, Jyoti; Rao, Sudha Narayana; Mugasimangalam, Raja C; Sirohi, Paramendra; Kochar, Sanjay K; Kochar, Dhanpat K; Das, Ashis

    2016-09-01

    Malarial parasite P. falciparum, an apicomplexan protozoan has a 23.3 MB nuclear genome and encodes ~ 5600 transcripts. The genetic diversity of the parasite within and across geographical zones is a challenge to gene expression studies which are essential for understanding of disease process, outcome and developing markers for diagnostics and prognostics. Here, we describe the strategy involved in designing a custom P. falciparum 15K array using the Agilent platform and Genotypic's Right Design methodology to study the transcriptome of Indian field isolates for which genome sequence information is limited. The array contains probes representing genome sequences of two distinct geographical isolates (i.e. 3D7 and HB3) and sub-telomeric var gene sequences of a third isolate (IT4) known to adhere in culture condition. Probes in the array have been selected based on their efficiency to detect transcripts through a 244K array experimentation. Array performance for the 15K array, was evaluated and validated using RNA materials from P. falciparum clinical isolates. A large percentage (91%) of the represented transcripts was detected from Indian P. falciparum patient isolates. Replicated probes and multiple probes representing the same gene showed perfect correlation between them suggesting good probe performance. Additional transcripts could be detected due to inclusion of unique probes representing HB3 strain transcripts. Variant surface antigen (VSA) transcripts were detected by optimized probes representing the VSA genes of three geographically distinct strains. The 15K cross strain P. falciparum array has shown good efficiency in detecting transcripts from P. falciparum parasite samples isolated from patients. The low parasite loads and presence of host RNA makes arrays a preferred platform for gene expression studies over RNA-Seq. PMID:27489776

  10. High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands

    PubMed Central

    Waltmann, Andreea; Darcy, Andrew W.; Harris, Ivor; Koepfli, Cristian; Lodo, John; Vahi, Ventis; Piziki, David; Shanks, G. Dennis; Barry, Alyssa E.; Whittaker, Maxine; Kazura, James W.; Mueller, Ivo

    2015-01-01

    Introduction Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. Methods In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). Results By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0–38.5%, p<0.001) and across age groups (5.3–25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. Conclusion P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and

  11. Detection of Plasmodium falciparum and Plasmodium vivax subclinical infection in non-endemic region: implications for blood transfusion and malaria epidemiology

    PubMed Central

    2014-01-01

    Background In Brazil, malaria is endemic in the Amazon River basin and non-endemic in the extra-Amazon region, which includes areas of São Paulo state. In this state, a number of autochthonous cases of malaria occur annually, and the prevalence of subclinical infection is unknown. Asymptomatic infections may remain undetected, maintaining transmission of the pathogen, including by blood transfusion. In these report it has been described subclinical Plasmodium infection in blood donors from a blood transfusion centre in São Paulo, Brazil. Methods In this cross-sectional study, representative samples of blood were obtained from 1,108 healthy blood donors at the Fundação Pró-Sangue Hemocentro de São Paulo, the main blood transfusion centre in São Paulo. Malaria exposure was defined by the home region (exposed: forest region; non-exposed: non-forest region). Real-time PCR was used to detect Plasmodium falciparum and Plasmodium vivax. Subclinical malaria cases were geo-referenced. Results Eighty-four (7.41%) blood donors tested positive for Plasmodium; 57 of these were infected by P. falciparum, 25 by P. vivax, and 2 by both. The prevalence of P. falciparum and P. vivax was 5.14 and 2.26, respectively. The overall prevalence ratio (PR) was 3.23 (95% confidence interval (CI) 2.03, 5.13); P. falciparum PR was 16.11 (95% CI 5.87, 44.21) and P. vivax PR was 0.47 (95% CI 0.2, 1.12). Plasmodium falciparum subclinical malaria infection in the Atlantic Forest domain was present in the mountain regions while P. vivax infection was observed in cities from forest-surrounded areas. Conclusions The presence of Plasmodium in healthy blood donors from a region known as non-endemic, which is important in the context of transfusion biosafety, was described. Infected recipients may become asymptomatic carriers and a reservoir for parasites, maintaining their transmission. Furthermore, P. falciparum PR was positively associated with the forest environment, and P. vivax was

  12. Plasma Uric Acid Levels Correlate with Inflammation and Disease Severity in Malian Children with Plasmodium falciparum Malaria

    PubMed Central

    Lopera-Mesa, Tatiana M.; Mita-Mendoza, Neida K.; van de Hoef, Diana L.; Doumbia, Saibou; Konaté, Drissa; Doumbouya, Mory; Gu, Wenjuan; Traoré, Karim; Diakité, Seidina A. S.; Remaley, Alan T.; Anderson, Jennifer M.; Rodriguez, Ana; Fay, Michael P.; Long, Carole A.; Diakité, Mahamadou; Fairhurst, Rick M.

    2012-01-01

    Background Plasmodium falciparum elicits host inflammatory responses that cause the symptoms and severe manifestations of malaria. One proposed mechanism involves formation of immunostimulatory uric acid (UA) precipitates, which are released from sequestered schizonts into microvessels. Another involves hypoxanthine and xanthine, which accumulate in parasitized red blood cells (RBCs) and may be converted by plasma xanthine oxidase to UA at schizont rupture. These two forms of ‘parasite-derived’ UA stimulate immune cells to produce inflammatory cytokines in vitro. Methods and Findings We measured plasma levels of soluble UA and inflammatory cytokines and chemokines (IL-6, IL-10, sTNFRII, MCP-1, IL-8, TNFα, IP-10, IFNγ, GM-CSF, IL-1β) in 470 Malian children presenting with uncomplicated malaria (UM), non-cerebral severe malaria (NCSM) or cerebral malaria (CM). UA levels were elevated in children with NCSM (median 5.74 mg/dl, 1.21-fold increase, 95% CI 1.09–1.35, n = 23, p = 0.0007) and CM (median 5.69 mg/dl, 1.19-fold increase, 95% CI 0.97–1.41, n = 9, p = 0.0890) compared to those with UM (median 4.60 mg/dl, n = 438). In children with UM, parasite density and plasma creatinine levels correlated with UA levels. These UA levels correlated with the levels of seven cytokines [IL-6 (r = 0.259, p<0.00001), IL-10 (r = 0.242, p<0.00001), sTNFRII (r = 0.221, p<0.00001), MCP-1 (r = 0.220, p<0.00001), IL-8 (r = 0.147, p = 0.002), TNFα (r = 0.132, p = 0.006) and IP-10 (r = 0.120, p = 0.012)]. In 39 children, UA levels were 1.49-fold (95% CI 1.34–1.65; p<0.0001) higher during their malaria episode [geometric mean titer (GMT) 4.67 mg/dl] than when they were previously healthy and aparasitemic (GMT 3.14 mg/dl). Conclusions Elevated UA levels may contribute to the pathogenesis of P. falciparum malaria by activating immune cells to produce inflammatory cytokines. While this study cannot identify the cause of

  13. Plasmodium falciparum circumsporozoite vaccine immunogenicity and efficacy trial with natural challenge quantitation in an area of endemic human malaria of Kenya.

    PubMed

    Sherwood, J A; Copeland, R S; Taylor, K A; Abok, K; Oloo, A J; Were, J B; Strickland, G T; Gordon, D M; Ballou, W R; Bales, J D; Wirtz, R A; Wittes, J; Gross, M; Que, J U; Cryz, S J; Oster, C N; Roberts, C R; Sadoff, J C

    1996-06-01

    It has been hypothesized that antibody induced by Plasmodium falciparum circumsporozoite protein vaccine would be effective against endemic human malaria. In a malaria endemic region of Kenya, 76 volunteers, in 38 pairs sleeping adjacently, were immunized with subunit circumsporozoite protein Asn-Ala-Asn-Pro tetrapeptide repeat-pseudomonas toxin A, or hepatitis B vaccine. After quinine and doxcycycline, volunteers were followed for illness daily, parasitemia weekly, antibody, T-lymphocyte responses, and treated if indicated. Anopheles mosquitoes resting in houses were collected, and tested for P. falciparum antigen, or dissected for sporozoites and tested for blood meal ABO type and P. falciparum antigen. Vaccine was safe, with side-effects similar in both groups, and immunogenic, engendering IgG antibody as high as 600 micrograms ml-1, but did not increase the proportion of volunteers with T-lymphocyte responses. Estimation of P. falciparum challenge averaged 0.194 potentially infective Anopheles bites/volunteer/ day. Mosquito blood meals showed no difference in biting intensity between vaccine and control groups. Both groups had similar malaria-free survival curves, cumulative positive blood slides, cumulative parasites mm-3, and numbers of parasites mm-3 on first positive blood slide, during three post-vaccination observation periods. Every volunteer had P. falciparum parastemia at least once. Vaccinees had 82% and controls 89% incidences of symptomatic parasitemia (P = 0.514, efficacy 9%, statistical power 95% probability of efficacy < 50%). Vaccine-induced anti-sporozoite antibody was not protective in this study. Within designed statistical precisions the present study is in agreement with efficacy studies in Colombia, Venezuela and Tanzania.

  14. Multiple stiffening effects of nanoscale knobs on human red blood cells infected with Plasmodium falciparum malaria parasite

    PubMed Central

    Zhang, Yao; Kim, Sangtae; Golkaram, Mahdi; Dixon, Matthew W. A.; Tilley, Leann; Li, Ju; Zhang, Sulin; Suresh, Subra

    2015-01-01

    During its asexual development within the red blood cell (RBC), Plasmodium falciparum (Pf), the most virulent human malaria parasite, exports proteins that modify the host RBC membrane. The attendant increase in cell stiffness and cytoadherence leads to sequestration of infected RBCs in microvasculature, which enables the parasite to evade the spleen, and leads to organ dysfunction in severe cases of malaria. Despite progress in understanding malaria pathogenesis, the molecular mechanisms responsible for the dramatic loss of deformability of Pf-infected RBCs have remained elusive. By recourse to a coarse-grained (CG) model that captures the molecular structures of Pf-infected RBC membrane, here we show that nanoscale surface protrusions, known as “knobs,” introduce multiple stiffening mechanisms through composite strengthening, strain hardening, and knob density-dependent vertical coupling. On one hand, the knobs act as structural strengtheners for the spectrin network; on the other, the presence of knobs results in strain inhomogeneity in the spectrin network with elevated shear strain in the knob-free regions, which, given its strain-hardening property, effectively stiffens the network. From the trophozoite to the schizont stage that ensues within 24–48 h of parasite invasion into the RBC, the rise in the knob density results in the increased number of vertical constraints between the spectrin network and the lipid bilayer, which further stiffens the membrane. The shear moduli of Pf-infected RBCs predicted by the CG model at different stages of parasite maturation are in agreement with experimental results. In addition to providing a fundamental understanding of the stiffening mechanisms of Pf-infected RBCs, our simulation results suggest potential targets for antimalarial therapies. PMID:25918423

  15. Angiopoietin-2 is associated with decreased endothelial nitric oxide and poor clinical outcome in severe falciparum malaria.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Gitawati, Retno; Tjitra, Emiliana; Kenangalem, Enny; Piera, Kim; Price, Ric N; Duffull, Stephen B; Celermajer, David S; Anstey, Nicholas M

    2008-11-01

    Adherence of parasitized erythrocytes to activated endothelium causes microvascular obstruction, tissue ischemia, and clinical complications in severe malaria (SM); however, the mechanisms leading to endothelial activation remain unclear. The angiogenic factors, angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF) are modulators of endothelial activation, with Ang-2 release from Weibel-Palade bodies (WPBs) being regulated by endothelial nitric oxide (NO). We explored the relationships between endothelial NO bioavailability, Ang-2, VEGF, tissue perfusion, and clinical outcomes in SM. We measured plasma Ang-2 and VEGF, together with biomarkers of severity from 146 adults with and without SM, in parallel with longitudinal measures of endothelial function by using reactive hyperemia peripheral arterial tonometry (a measure of endothelial NO bioavailability). Regression was used to relate concentrations of Ang-2/VEGF with malaria disease severity, biomarkers of perfusion, endothelial activation, and parasite biomass. The longitudinal relationship between Ang-2 and endothelial function was assessed by using a mixed-effects model. Ang-2 concentrations were elevated in SM and associated with increased venous lactate, plasma intercellular cell adhesion molecule-1 concentrations, parasite biomass, and mortality. In contrast, VEGF concentrations were inversely associated with these biomarkers. Ang-2 concentrations were significantly better predictors of death than venous lactate (P = 0.03). Recovery of endothelial function was associated with falling concentrations of Ang-2. Ang-2 release from endothelial cells with reduced NO bioavailability is likely to contribute to endothelial activation, sequestered parasite biomass, impaired perfusion, and poor outcome in severe falciparum malaria. Agents that improve endothelial NO, reduce WPB exocytosis, and/or antagonize Ang-2 may have therapeutic roles in SM.

  16. Two Imported Malaria Cases Caused by Plasmodium falciparum in A Week.

    PubMed

    Erdil, Zeynep; Kurt, Celali; Kalaycı, Hacer Özlem; Gözlükaya, Özgül; Tayar, Cemal

    2016-06-01

    Malaria is a condition that threatens millions of people in many countries in spite of precautions. Sporadic cases have not been observed in our country since 2010, but imported malaria cases are still to be seen because of migration. In this study, two malaria cases are presented that appeared in a non-endemic region within 1 week. Complaints appeared 20 days later after leaving Ivory Coast in the first case and one week after returning from Ghana in the second case. With this two import cases which have a travel story about two different countries and non taking regular chemoprophylaxis; it is aimed to call attention that malaria is a question of common concern and a protozoon which needs to be struggled worldwide. PMID:27594293

  17. The Association of K76T Mutation in Pfcrt Gene and Chloroquine Treatment Failure in Uncomplicated Plasmodium falciparum Malaria in a Cohort of Nigerian Children

    NASA Astrophysics Data System (ADS)

    Umar, R. A.; Hassan, S. W.; Ladan, M. J.; Nma Jiya, M.; Abubakar, M. K.; Nata`Ala, U.

    The aim of this study was to evaluate the association of K76T mutation in Pfcrt gene and chloroquine treatment failure following reports that the efficacy of chloroquine in the treatment of uncomplicated falciparum malaria in Africa is seriously compromised by high levels of drug resistance. The occurrence of mutation on codon 76 of Plasmodium falciparum chloroquine resistance transporter (Pfcrt) gene has been associated with development of resistance to chloroquine. We investigated the association of K76T mutation in Pfcrt gene in malaria-infected blood samples from a cohort of Nigerian children with uncomplicated falciparum malaria treated with chloroquine and its association with clinical (in vivo) resistance. The Pfcrt T76 allele was very significantly associated with resistance to chloroquine (Fischer exact test: p = 0.0001). We conclude that K76T mutation in Pfcrt gene is significantly associated with chloroquine resistance and that it could be used as a population marker for chloroquine resistance in this part of the country

  18. Rosette-Disrupting Effect of an Anti-Plasmodial Compound for the Potential Treatment of Plasmodium falciparum Malaria Complications.

    PubMed

    Ch'ng, Jun-Hong; Moll, Kirsten; Quintana, Maria Del Pilar; Chan, Sherwin Chun Leung; Masters, Ellen; Moles, Ernest; Liu, Jianping; Eriksson, Anders B; Wahlgren, Mats

    2016-07-11

    The spread of artemisinin-resistant parasites could lead to higher incidence of patients with malaria complications. However, there are no current treatments that directly dislodge sequestered parasites from the microvasculature. We show that four common antiplasmodial drugs do not disperse rosettes (erythrocyte clusters formed by malaria parasites) and therefore develop a cell-based high-throughput assay to identify potential rosette-disrupting compounds. A pilot screen of 2693 compounds identified Malaria Box compound MMV006764 as a potential candidate. Although it reduced rosetting by a modest 20%, MMV006764 was validated to be similarly effective against both blood group O and A rosettes of three laboratory parasite lines. Coupled with its antiplasmodial activity and drug-likeness, MMV006764 represents the first small-molecule compound that disrupts rosetting and could potentially be used in a resource-limited setting to treat patients deteriorating rapidly from malaria complications. Such dual-action drugs that simultaneously restore microcirculation and reduce parasite load could significantly reduce malaria morbidity and mortality.

  19. Rosette-Disrupting Effect of an Anti-Plasmodial Compound for the Potential Treatment of Plasmodium falciparum Malaria Complications

    PubMed Central

    Ch’ng, Jun-Hong; Moll, Kirsten; Quintana, Maria del Pilar; Chan, Sherwin Chun Leung; Masters, Ellen; Moles, Ernest; Liu, Jianping; Eriksson, Anders B.; Wahlgren, Mats

    2016-01-01

    The spread of artemisinin-resistant parasites could lead to higher incidence of patients with malaria complications. However, there are no current treatments that directly dislodge sequestered parasites from the microvasculature. We show that four common antiplasmodial drugs do not disperse rosettes (erythrocyte clusters formed by malaria parasites) and therefore develop a cell-based high-throughput assay to identify potential rosette-disrupting compounds. A pilot screen of 2693 compounds identified Malaria Box compound MMV006764 as a potential candidate. Although it reduced rosetting by a modest 20%, MMV006764 was validated to be similarly effective against both blood group O and A rosettes of three laboratory parasite lines. Coupled with its antiplasmodial activity and drug-likeness, MMV006764 represents the first small-molecule compound that disrupts rosetting and could potentially be used in a resource-limited setting to treat patients deteriorating rapidly from malaria complications. Such dual-action drugs that simultaneously restore microcirculation and reduce parasite load could significantly reduce malaria morbidity and mortality. PMID:27403804

  20. Rosette-Disrupting Effect of an Anti-Plasmodial Compound for the Potential Treatment of Plasmodium falciparum Malaria Complications.

    PubMed

    Ch'ng, Jun-Hong; Moll, Kirsten; Quintana, Maria Del Pilar; Chan, Sherwin Chun Leung; Masters, Ellen; Moles, Ernest; Liu, Jianping; Eriksson, Anders B; Wahlgren, Mats

    2016-01-01

    The spread of artemisinin-resistant parasites could lead to higher incidence of patients with malaria complications. However, there are no current treatments that directly dislodge sequestered parasites from the microvasculature. We show that four common antiplasmodial drugs do not disperse rosettes (erythrocyte clusters formed by malaria parasites) and therefore develop a cell-based high-throughput assay to identify potential rosette-disrupting compounds. A pilot screen of 2693 compounds identified Malaria Box compound MMV006764 as a potential candidate. Although it reduced rosetting by a modest 20%, MMV006764 was validated to be similarly effective against both blood group O and A rosettes of three laboratory parasite lines. Coupled with its antiplasmodial activity and drug-likeness, MMV006764 represents the first small-molecule compound that disrupts rosetting and could potentially be used in a resource-limited setting to treat patients deteriorating rapidly from malaria complications. Such dual-action drugs that simultaneously restore microcirculation and reduce parasite load could significantly reduce malaria morbidity and mortality. PMID:27403804

  1. Neurological manifestations of malaria.

    PubMed

    Román, G C; Senanayake, N

    1992-03-01

    The involvement of the nervous system in malaria is reviewed in this paper. Cerebral malaria, the acute encephalopathy which complicates exclusively the infection by Plasmodium falciparum commonly affects children and adolescents in hyperendemic areas. Plugging of cerebral capillaries and venules by clumped, parasitized red cells causing sludging in the capillary circulation is one hypothesis to explain its pathogenesis. The other is a humoral hypothesis which proposes nonspecific, immune-mediated, inflammatory responses with release of vasoactive substances capable of producing endothelial damage and alterations of permeability. Cerebral malaria has a mortality rate up to 50%, and also a considerable longterm morbidity, particularly in children. Hypoglycemia, largely in patients treated with quinine, may complicate the cerebral symptomatology. Other central nervous manifestations of malaria include intracranial hemorrhage, cerebral arterial occlusion, and transient extrapyramidal and neuropsychiatric manifestations. A self-limiting, isolated cerebellar ataxia, presumably caused by immunological mechanisms, in patients recovering from falciparum malaria has been recognized in Sri Lanka. Malaria is a common cause of febrile seizures in the tropics, and it also contributes to the development of epilepsy in later life. Several reports of spinal cord and peripheral nerve involvement are also available. A transient muscle paralysis resembling periodic paralysis during febrile episodes of malaria has been described in some patients. The pathogenesis of these neurological manifestations remains unexplored, but offers excellent perspectives for research at a clinical as well as experimental level. PMID:1307475

  2. A survey of malaria and some arboviral infections among suspected febrile patients visiting a health centre in Simawa, Ogun State, Nigeria.

    PubMed

    Ayorinde, Adenola F; Oyeyiga, Ayorinde M; Nosegbe, Nwakaego O; Folarin, Onikepe A

    2016-01-01

    Most febrile patients are often misdiagnosed with malaria due to similar symptoms, such as fever shared by malaria and certain arboviral infections. This study surveyed the incidence of malaria, chikungunya and dengue infections among a number of suspected febrile patients visiting Simawa Health Centre, Ogun State, Nigeria. Venous blood samples were obtained from 60 febrile patients (age 3-70 years) visiting the centre between April and May 2014. The rapid diagnostic test (RDT) was used to detect the presence of chikungunya (CHK) antibodies (IgM), dengue (DEN) virus and antibodies (NS1, IgM and IgG) and malaria parasites (Plasmodium falciparum and Plasmodium vivax). Malarial confirmatory tests were by microscopy and nested polymerase chain reaction (PCR) using the polymorphic region of Glutamate-Rich Protein (GLURP) gene. The complexity of P. falciparum infection in the community also determined by the use of nested PCR. These three mosquito-borne infections were observed in 63% (38) of the patients. The prevalence of CHK, DEN and malarial infections singularly were 11%, 0% and 63%, respectively, whereas malaria with either CHK or DEN infections were 24% (9) and 3% (1), respectively. No subjects were positive for CHK and DEN co-infection. Malarial microscopic confirmation was in 94% (32) of the malaria RDT-positive samples, 50% (17) were successfully analysed by nested PCR and the mean multiplicity of infection was 1.6 (1-3 clones). One patient sample harboured both P. falciparum and P. vivax. The study reports the presence of some arboviral infections having similar symptoms with malaria at Simawa, Ogun State. The proper diagnosis of infectious diseases is important for controlling them.

  3. Detection of the Plasmodium falciparum antigen histidine-rich protein 2 in blood of pregnant women: implications for diagnosing placental malaria.

    PubMed

    Leke, R F; Djokam, R R; Mbu, R; Leke, R J; Fogako, J; Megnekou, R; Metenou, S; Sama, G; Zhou, Y; Cadigan, T; Parra, M; Taylor, D W

    1999-09-01

    Pregnant women have an increased susceptibility to infection by Plasmodium falciparum. Parasites may be present in the placenta yet not detectable in peripheral blood smears by routine light microscopy. In order to determine how frequently misdiagnosis occurs, peripheral blood and placental samples were collected from 1,077 Cameroonian women at the time of giving birth and examined for the presence of malarial parasites by using light microscopy. Results showed that 20.1% of the women who had placental malaria were peripheral blood smear negative. Thus, malarial infection was not detected by microscopic examination of peripheral blood smears from approximately one out of five malaria-infected women. Since P. falciparum parasites secrete histidine-rich protein 2 (HRP-2), we sought to determine if detecting HRP-2 in either peripheral plasma or whole blood might be used to diagnose the presence of parasites "hidden" in the placenta. Samples of peripheral plasma from 127 women with different levels of placental malarial infection were assayed by HRP-2-specific enzyme-linked immunosorbent assay. HRP-2 was detected in 88% of the women with placental malaria who tested negative by blood smear. Additionally, whole blood was obtained from 181 women and tested for HRP-2 with a rapid, chromatographic strip test (ICT). The ICT test accurately detected malarial infection in 89.1% of P. falciparum-infected women. Furthermore, 94% of women with malaria were accurately diagnosed by using a combination of microscopy and the ICT test. Thus, detection of HRP-2 in conjunction with microscopy should improve diagnosis of malaria in pregnant women.

  4. Advances in mapping malaria for elimination: fine resolution modelling of Plasmodium falciparum incidence

    PubMed Central

    Alegana, Victor A.; Atkinson, Peter M.; Lourenço, Christopher; Ruktanonchai, Nick W.; Bosco, Claudio; Erbach-Schoenberg, Elisabeth zu; Didier, Bradley; Pindolia, Deepa; Le Menach, Arnaud; Katokele, Stark; Uusiku, Petrina; Tatem, Andrew J.

    2016-01-01

    The long-term goal of the global effort to tackle malaria is national and regional elimination and eventually eradication. Fine scale multi-temporal mapping in low malaria transmission settings remains a challenge and the World Health Organisation propose use of surveillance in elimination settings. Here, we show how malaria incidence can be modelled at a fine spatial and temporal resolution from health facility data to help focus surveillance and control to population not attending health facilities. Using Namibia as a case study, we predicted the incidence of malaria, via a Bayesian spatio-temporal model, at a fine spatial resolution from parasitologically confirmed malaria cases and incorporated metrics on healthcare use as well as measures of uncertainty associated with incidence predictions. We then combined the incidence estimates with population maps to estimate clinical burdens and show the benefits of such mapping to identifying areas and seasons that can be targeted for improved surveillance and interventions. Fine spatial resolution maps produced using this approach were then used to target resources to specific local populations, and to specific months of the season. This remote targeting can be especially effective where the population distribution is sparse and further surveillance can be limited to specific local areas. PMID:27405532

  5. Advances in mapping malaria for elimination: fine resolution modelling of Plasmodium falciparum incidence.

    PubMed

    Alegana, Victor A; Atkinson, Peter M; Lourenço, Christopher; Ruktanonchai, Nick W; Bosco, Claudio; Erbach-Schoenberg, Elisabeth Zu; Didier, Bradley; Pindolia, Deepa; Le Menach, Arnaud; Katokele, Stark; Uusiku, Petrina; Tatem, Andrew J

    2016-01-01

    The long-term goal of the global effort to tackle malaria is national and regional elimination and eventually eradication. Fine scale multi-temporal mapping in low malaria transmission settings remains a challenge and the World Health Organisation propose use of surveillance in elimination settings. Here, we show how malaria incidence can be modelled at a fine spatial and temporal resolution from health facility data to help focus surveillance and control to population not attending health facilities. Using Namibia as a case study, we predicted the incidence of malaria, via a Bayesian spatio-temporal model, at a fine spatial resolution from parasitologically confirmed malaria cases and incorporated metrics on healthcare use as well as measures of uncertainty associated with incidence predictions. We then combined the incidence estimates with population maps to estimate clinical burdens and show the benefits of such mapping to identifying areas and seasons that can be targeted for improved surveillance and interventions. Fine spatial resolution maps produced using this approach were then used to target resources to specific local populations, and to specific months of the season. This remote targeting can be especially effective where the population distribution is sparse and further surveillance can be limited to specific local areas. PMID:27405532

  6. Antibody responses to the merozoite surface protein-1 complex in cerebral malaria patients in India

    PubMed Central

    Lucchi, Naomi W; Tongren, Jon Eric; Jain, Vidhan; Nagpal, Avinash C; Kauth, Christian W; Woehlbier, Ute; Bujard, Hermann; Dash, Aditya P; Singh, Neeru; Stiles, Jonathan K; Udhayakumar, Venkatachalam

    2008-01-01

    Background Plasmodium falciparum infection causes cerebral malaria (CM) in a subset of patients with anti-malarial treatment protecting only about 70% to 80% of patients. Why a subset of malaria patients develops CM complications, including neurological sequelae or death, is still not well understood. It is believed that host immune factors may modulate CM outcomes and there is substantial evidence that cellular immune factors, such as cytokines, play an important role in this process. In this study, the potential relationship between the antibody responses to the merozoite surface protein (MSP)-1 complex (which consists of four fragments namely: MSP-183, MSP-130, MSP-138 and MSP-142), MSP-636 and MSP-722 and CM was investigated. Methods Peripheral blood antibody responses to recombinant antigens of the two major allelic forms of MSP-1 complex, MSP-636 and MSP-722 were compared between healthy subjects, mild malaria patients (MM) and CM patients residing in a malaria endemic region of central India. Total IgG and IgG subclass antibody responses were determined using ELISA method. Results The prevalence and levels of IgG and its subclasses in the plasma varied for each antigen. In general, the prevalence of total IgG, IgG1 and IgG3 was higher in the MM patients and lower in CM patients compared to healthy controls. Significantly lower levels of total IgG antibodies to the MSP-1f38, IgG1 levels to MSP-1d83, MSP-119 and MSP-636 and IgG3 levels to MSP-1f42 and MSP-722 were observed in CM patients as compared to MM patients. Conclusion These results suggest that there may be some dysregulation in the generation of antibody responses to some MSP antigens in CM patients and it is worth investigating further whether perturbations of antibody responses in CM patients contribute to pathogenesis. PMID:18601721

  7. Studies on the humoral immune response to a synthetic vaccine against Plasmodium falciparum malaria.

    PubMed Central

    Salcedo, M; Barreto, L; Rojas, M; Moya, R; Cote, J; Patarroyo, M E

    1991-01-01

    A synthetic vaccine against the asexual blood stages of P. falciparum, the SPf 66 synthetic hybrid polymer, composed of peptides derived from three merozoite membrane proteins as well as one peptide from the sporozoite CS protein, has been developed by our group and tested in different protection assays in Aotus monkeys as well as in human volunteers. This study evaluates the humoral immune response induced by the SPf 66 protein vaccination in adult human volunteers from the Colombian Pacific coast as follows: determination of specific IgG antibody levels against SPf 66 by FAST-ELISA after each immunization; analysis of antibody reactivity with P. falciparum schizont lysates by immunoblots; and determination of the in vitro parasite growth inhibition. A clear boosting effect, dependent on time and dose, was observed in the antibody production kinetics. These antibodies also specifically recognize three proteins of the P. falciparum schizont lysate corresponding to the molecular weights of the proteins from which the amino acid sequence was derived. These sera were also capable of markedly inhibiting in vitro parasite growth. PMID:2015702

  8. Multicentre study evaluating the non-inferiority of the new paediatric formulation of artesunate/amodiaquine versus artemether/lumefantrine for the management of uncomplicated Plasmodium falciparum malaria in children in Cameroon, Ivory Coast and Senegal

    PubMed Central

    2012-01-01

    Background This multicentre study was carried out in Cameroon, Ivory Coast and Senegal to evaluate the non-inferiority of the new paediatric formulation of artesunate/amodiaquine (AS+AQ)(Camoquin-Plus Paediatric®) in suspension form versus artemether/lumefantrine (AL)(Coartem®) in the management of African children with uncomplicated falciparum malaria. Methods It was an open randomized trial including children aged between 7 months and 7 years. The endpoints were Adequate Clinical and Parasitological Response (ACPR) at day 28, the clinical and biological tolerability. Statistical analyses were done in Intention To Treat (ITT) and in Per protocol (PP). Results At the end of the study 481 patients were enrolled in the three countries (249 in the AS+AQ arm and 232 in the AL arm). ACRP in ITT after PCR correction did not show any statistical difference between the two groups with 97.6% for AS+AQ versus 94.8% for AL. In the PP analysis, the corrected ACRP were respectively 98.7% and 96.9% for the two regimens. The clinical tolerance was good without significant difference. Anaemia was significantly higher at D7 in the two groups compared to D0. Conclusion This study demonstrates the non-inferiority of AS+AQ versus AL, its efficacy and tolerance in the management of uncomplicated Plasmodium falciparum malaria in African children. PMID:23270636

  9. Comparative performance of the ParaSight F test for detection of Plasmodium falciparum in malaria-immune and nonimmune populations in Irian Jaya, Indonesia.

    PubMed

    Fryauff, D J; Gomez-Saladin, E; Purnomo; Sumawinata, I; Sutamihardja, M A; Tuti, S; Subianto, B; Richie, T L

    1997-01-01

    A comparison was made of the performance of the ParaSight F test (F test) for detection of Plasmodium falciparum in blood from malaria-immune (410 native Irianese) and nonimmune (369 new transmigrants) populations in Irian Jaya, Indonesia, where malaria is hyperendemic and all four species of human malaria occur. There were highly significant differences between populations in the sensitivity (Irianese, 60% versus transmigrants, 84%; P < 0.001) and specificity (Irianese, 97% versus transmigrants, 84%; P < 0.001) of the F test. The test had comparably high levels of sensitivity for Irianese children aged < or = 10 years, both age groups of transmigrants (76-85%), but low sensitivity for Irianese aged > 10 years (40%), among whom only 7% of parasitaemias < 120 per microliter and 69% of those > 120 per microliter were detected. Specificity was comparably high for transmigrant children aged < or = 10 years and both age groups of Irianese (93-98%). The low specificity for transmigrants aged > 10 years (79%) was due to a preponderance of false positives, frequently identified by microscopy as P. vivax. The results suggest that comparison based on microscopy underestimated the performance of the ParaSight F test and that malaria immune status, irrespective of P. falciparum density, may influence the test's sensitivity.

  10. Imported malaria cases in Okinawa Prefecture, Japan.

    PubMed

    Higa, Futoshi; Tateyama, Masao; Tasato, Daisuke; Karimata, Yosuke; Nakamura, Hideta; Miyagi, Kazuya; Haranaga, Shusaku; Hirata, Tetsuo; Hokama, Akira; Cash, Haley L; Toma, Hiromu; Fujita, Jiro

    2013-01-01

    With the increase in global transportation, imported malaria has become a significant public health concern in Japan. In the present study, we retrospectively analyzed all imported malaria cases in Okinawa Prefecture from 1988 to 2012. In that period, 23 patients with imported malaria were admitted to the University of the Ryukyus Hospital. Malaria types observed included Plasmodium falciparum (14 cases), P. vivax (7 cases), combined P. falciparum and P. ovale (1 case), and combined P. vivax and P. malariae (1 case). All cases were resolved by anti-malarial treatment. The clinical data from these patients highlights the importance of collecting patient travel history and ensuring an adequate supply of both diagnostic test and drug treatments in Okinawa.

  11. Impaired systemic tetrahydrobiopterin bioavailability and increased dihydrobiopterin in adult falciparum malaria: association with disease severity, impaired microvascular function and increased endothelial activation.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Kenangalem, Enny; Tjitra, Emiliana; Price, Ric N; Weinberg, J Brice; Hyland, Keith; Granger, Donald L; Anstey, Nicholas M

    2015-03-01

    Tetrahydrobiopterin (BH₄) is a co-factor required for catalytic activity of nitric oxide synthase (NOS) and amino acid-monooxygenases, including phenylalanine hydroxylase. BH4 is unstable: during oxidative stress it is non-enzymatically oxidized to dihydrobiopterin (BH₂), which inhibits NOS. Depending on BH₄ availability, NOS oscillates between NO synthase and NADPH oxidase: as the BH₄/BH₂ ratio decreases, NO production falls and is replaced by superoxide. In African children and Asian adults with severe malaria, NO bioavailability decreases and plasma phenylalanine increases, together suggesting possible BH₄ deficiency. The primary three biopterin metabolites (BH₄, BH₂ and B₀ [biopterin]) and their association with disease severity have not been assessed in falciparum malaria. We measured pterin metabolites in urine of adults with severe falciparum malaria (SM; n=12), moderately-severe malaria (MSM, n=17), severe sepsis (SS; n=5) and healthy subjects (HC; n=20) as controls. In SM, urinary BH₄ was decreased (median 0.16 ¼mol/mmol creatinine) compared to MSM (median 0.27), SS (median 0.54), and HC (median 0.34)]; p<0.001. Conversely, BH₂ was increased in SM (median 0.91 ¼mol/mmol creatinine), compared to MSM (median 0.67), SS (median 0.39), and HC (median 0.52); p<0.001, suggesting increased oxidative stress and insufficient recycling of BH2 back to BH4 in severe malaria. Overall, the median BH₄/BH₂ ratio was lowest in SM [0.18 (IQR: 0.04-0.32)] compared to MSM (0.45, IQR 0.27-61), SS (1.03; IQR 0.54-2.38) and controls (0.66; IQR 0.43-1.07); p<0.001. In malaria, a lower BH₄/BH₂ ratio correlated with decreased microvascular reactivity (r=0.41; p=0.03) and increased ICAM-1 (r=-0.52; p=0.005). Decreased BH4 and increased BH₂ in severe malaria (but not in severe sepsis) uncouples NOS, leading to impaired NO bioavailability and potentially increased oxidative stress. Adjunctive therapy to regenerate BH4 may have a role in improving NO

  12. Genetic variation in the Plasmodium falciparum circumsporozoite protein in India and its relevance to RTS,S malaria vaccine.

    PubMed

    Zeeshan, Mohammad; Alam, Mohammad Tauqeer; Vinayak, Sumiti; Bora, Hema; Tyagi, Rupesh Kumar; Alam, Mohd Shoeb; Choudhary, Vandana; Mittra, Pooja; Lumb, Vanshika; Bharti, Praveen Kumar; Udhayakumar, Venkatachalam; Singh, Neeru; Jain, Vidhan; Singh, Pushpendra Pal; Sharma, Yagya Dutta

    2012-01-01

    RTS,S is the most advanced malaria vaccine candidate, currently under phase-III clinical trials in Africa. This Plasmodium falciparum vaccine contains part of the central repeat region and the complete C-terminal T cell epitope region (Th2R and Th3R) of the circumsporozoite protein (CSP). Since naturally occurring polymorphisms at the vaccine candidate loci are critical determinants of the protective efficacy of the vaccines, it is imperative to investigate these polymorphisms in field isolates. In this study we have investigated the genetic diversity at the central repeat, C-terminal T cell epitope (Th2R and Th3R) and N-terminal T cell epitope regions of the CSP, in P. falciparum isolates from Madhya Pradesh state of India. These isolates were collected through a 5-year prospective study aimed to develop a well-characterized field-site for the future evaluation of malaria vaccine in India. Our results revealed that the central repeat (63 haplotypes, n = 161) and C-terminal Th2R/Th3R epitope (24 haplotypes, n = 179) regions were highly polymorphic, whereas N-terminal non-repeat region was less polymorphic (5 haplotypes, n = 161) in this population. We did not find any evidence of the role of positive natural selection in maintaining the genetic diversity at the Th2R/Th3R regions of CSP. Comparative analysis of the Th2R/Th3R sequences from this study to the global isolates (n = 1160) retrieved from the GenBank database revealed two important points. First, the majority of the sequences (~61%, n = 179) from this study were identical to the Dd2/Indochina type, which is also the predominant Th2R/Th3R haplotype in Asia (~59%, n = 974). Second, the Th2R/Th3R sequences in Asia, South America and Africa are geographically distinct with little allele sharing between continents. In conclusion, this study provides an insight on the existing polymorphisms in the CSP in a parasite population from India that could potentially influence the efficacy of RTS,S vaccine in this

  13. [A histologic study of brain in fatal cerebral malaria].

    PubMed

    Burel-Vandenbos, Fanny; Effa'a, Christian; Alunni, Véronique; Cardot-Leccia, Nathalie; Haudebourg, Juliette; Michiels, Jean-François

    2008-12-01

    Plasmodium falciparum infection is an emergency because of the risk of cerebral malaria, that is the most severe complication. Malaria diagnosis is usually made on blood samples of feverish patients coming from endemic area. The pathologist is rarely confronted with malaria lesions. If the occasion arises, the diagnosis of malaria is often already known or suspected and the pathologist has to confirm it. Rarely, malaria is unknown before histological examination and the diagnosis is based on the identification of specific histological features. We report a case of sudden death due to cerebral malaria diagnosed on autopsy findings. PMID:19084718

  14. Polymorphisms in host genes encoding NOSII, C-reactive protein, and adhesion molecules thrombospondin and E-selectin are risk factors for Plasmodium falciparum malaria in India.

    PubMed

    Kanchan, K; Pati, S S; Mohanty, S; Mishra, S K; Sharma, S K; Awasthi, S; Venkatesh, V; Habib, S

    2015-10-01

    Cytoadherence of Plasmodium falciparum-infected red blood cells (RBCs) in host microvasculature and complex regulation of the immune response are important contributors to the clinical outcome of disease. We tested the association of 23 single nucleotide polymorphisms (SNPs) and a microsatellite repeat in adhesion molecule genes THBS1 and ESEL, and immune regulatory molecule genes NOSII, CRP, and MBL2 with falciparum malaria in populations residing in a malaria-endemic and a non-endemic region of India. The THBS1 haplotype CCCCA (rs1478604, rs7170682, rs2664141, rs12912082, rs3743125) was a risk factor in the endemic region (relative risk = 3.78) and an ESEL SNP (rs5368, His468Tyr) associated with cerebral malaria (CM) [CM vs. non-cerebral malaria (NCM), odds ratio (OR) = 2.23, p = 0.03]. In the non-endemic region, an ESEL 3'UTR SNP (rs5359) associated with enhanced risk of disease (OR = 3.62, p = 1 × 10(-4)) and the CT genotype of the CRP promoter SNP (C/T/A) strongly associated with protection (severe vs. control, OR = 0.29, p = 6 × 10(-5)). Long repeat alleles of the NOSII promoter microsatellite (CCTTT)n exhibited strong association with protection and the NOSII ATG haplotype (rs3729508, rs2297520, rs9282801) was strongly protective against severe malaria in both regions (endemic, severe vs. control, OR = 0.05, p = 0.0001; non-endemic, severe vs. control, OR = 0.3, p = 1 × 10(-5)). Our results suggest differential contribution of variants of the investigated genes in determining the outcome of malaria in Indian populations.

  15. Human immune system mice immunized with Plasmodium falciparum circumsporozoite protein induce protective human humoral immunity against malaria.

    PubMed

    Huang, Jing; Li, Xiangming; Coelho-dos-Reis, Jordana G A; Zhang, Min; Mitchell, Robert; Nogueira, Raquel Tayar; Tsao, Tiffany; Noe, Amy R; Ayala, Ramses; Sahi, Vincent; Gutierrez, Gabriel M; Nussenzweig, Victor; Wilson, James M; Nardin, Elizabeth H; Nussenzweig, Ruth S; Tsuji, Moriya

    2015-12-01

    In this study, we developed human immune system (HIS) mice that possess functional human CD4+ T cells and B cells, named HIS-CD4/B mice. HIS-CD4/B mice were generated by first introducing HLA class II genes, including DR1 and DR4, along with genes encoding various human cytokines and human B cell activation factor (BAFF) to NSG mice by adeno-associated virus serotype 9 (AAV9) vectors, followed by engrafting human hematopoietic stem cells (HSCs). HIS-CD4/B mice, in which the reconstitution of human CD4+ T and B cells resembles to that of humans, produced a significant level of human IgG against Plasmodium falciparum circumsporozoite (PfCS) protein upon immunization. CD4+ T cells in HIS-CD4/B mice, which possess central and effector memory phenotypes like those in humans, are functional, since PfCS protein-specific human CD4+ T cells secreting IFN-γ and IL-2 were detected in immunized HIS-CD4/B mice. Lastly, PfCS protein-immunized HIS-CD4/B mice were protected from in vivo challenge with transgenic P. berghei sporozoites expressing the PfCS protein. The immune sera collected from protected HIS-CD4/B mice reacted against transgenic P. berghei sporozoites expressing the PfCS protein and also inhibited the parasite invasion into hepatocytes in vitro. Taken together, these studies show that our HIS-CD4/B mice could mount protective human anti-malaria immunity, consisting of human IgG and human CD4+ T cell responses both specific for a human malaria antigen.

  16. Artemether-Lumefantrine Pharmacokinetics and Clinical Response Are Minimally Altered in Pregnant Ugandan Women Treated for Uncomplicated Falciparum Malaria

    PubMed Central

    Nyunt, Myaing M.; Nguyen, Vy K.; Kajubi, Richard; Huang, Liusheng; Ssebuliba, Joshua; Kiconco, Sylvia; Mwima, Moses W.; Achan, Jane; Aweeka, Francesca

    2015-01-01

    Artemether-lumefantrine is a first-line regimen for the treatment of uncomplicated malaria during the second and third trimesters of pregnancy. Previous studies have reported changes in the pharmacokinetics and clinical outcomes following treatment with artemether-lumefantrine in pregnant women compared to nonpregnant adults; however, the results are inconclusive. We conducted a study in rural Uganda to compare the pharmacokinetics of artemether-lumefantrine and the treatment responses between 30 pregnant women and 30 nonpregnant adults with uncomplicated Plasmodium falciparum malaria. All participants were uninfected with HIV, treated with a six-dose regimen of artemether-lumefantrine, and monitored clinically for 42 days. The pharmacokinetics of artemether, its metabolite dihydroartemisinin, and lumefantrine were evaluated for 21 days following treatment. We found no significant differences in the overall pharmacokinetics of artemether, dihydroartemisinin, or lumefantrine in a direct comparison of pregnant women to nonpregnant adults, except for a statistically significant but small difference in the terminal elimination half-lives of both dihydroartemisinin and lumefantrine. There were seven PCR-confirmed reinfections (5 pregnant and 2 nonpregnant participants). The observation of a shorter terminal half-life for lumefantrine may have contributed to a higher frequency of reinfection or a shorter posttreatment prophylactic period in pregnant women than in nonpregnant adults. While the comparable overall pharmacokinetic exposure is reassuring, studies are needed to further optimize antimalarial efficacy in pregnant women, particularly in high-transmission settings and because of emerging drug resistance. (This study is registered at ClinicalTrials.gov under registration no. NCT01717885.) PMID:26666942

  17. Human immune system mice immunized with Plasmodium falciparum circumsporozoite protein induce protective human humoral immunity against malaria.

    PubMed

    Huang, Jing; Li, Xiangming; Coelho-dos-Reis, Jordana G A; Zhang, Min; Mitchell, Robert; Nogueira, Raquel Tayar; Tsao, Tiffany; Noe, Amy R; Ayala, Ramses; Sahi, Vincent; Gutierrez, Gabriel M; Nussenzweig, Victor; Wilson, James M; Nardin, Elizabeth H; Nussenzweig, Ruth S; Tsuji, Moriya

    2015-12-01

    In this study, we developed human immune system (HIS) mice that possess functional human CD4+ T cells and B cells, named HIS-CD4/B mice. HIS-CD4/B mice were generated by first introducing HLA class II genes, including DR1 and DR4, along with genes encoding various human cytokines and human B cell activation factor (BAFF) to NSG mice by adeno-associated virus serotype 9 (AAV9) vectors, followed by engrafting human hematopoietic stem cells (HSCs). HIS-CD4/B mice, in which the reconstitution of human CD4+ T and B cells resembles to that of humans, produced a significant level of human IgG against Plasmodium falciparum circumsporozoite (PfCS) protein upon immunization. CD4+ T cells in HIS-CD4/B mice, which possess central and effector memory phenotypes like those in humans, are functional, since PfCS protein-specific human CD4+ T cells secreting IFN-γ and IL-2 were detected in immunized HIS-CD4/B mice. Lastly, PfCS protein-immunized HIS-CD4/B mice were protected from in vivo challenge with transgenic P. berghei sporozoites expressing the PfCS protein. The immune sera collected from protected HIS-CD4/B mice reacted against transgenic P. berghei sporozoites expressing the PfCS protein and also inhibited the parasite invasion into hepatocytes in vitro. Taken together, these studies show that our HIS-CD4/B mice could mount protective human anti-malaria immunity, consisting of human IgG and human CD4+ T cell responses both specific for a human malaria antigen. PMID:26410104

  18. Dihydroartemisinin-Piperaquine Treatment of Multidrug Resistant Falciparum and Vivax Malaria in Pregnancy

    PubMed Central

    Poespoprodjo, Jeanne Rini; Fobia, Wendy; Kenangalem, Enny; Lampah, Daniel A.; Sugiarto, Paulus; Tjitra, Emiliana; Anstey, Nicholas M.; Price, Ric N.

    2014-01-01

    Background Artemisinin combination therapy (ACT) is recommended for the treatment of multidrug resistant malaria in the second and third trimesters of pregnancy, but the experience with ACTs is limited. We review the exposure of pregnant women to the combination dihydroartemisinin-piperaquine over a 6 year period. Methods From April 2004–June 2009, a prospective hospital-based surveillance screened all pregnant women for malaria and documented maternal and neonatal outcomes. Results Data were available on 6519 pregnant women admitted to hospital; 332 (5.1%) women presented in the first trimester, 324 (5.0%) in the second, 5843 (89.6%) in the third, and in 20 women the trimester was undocumented. Peripheral parasitaemia was confirmed in 1682 women, of whom 106 (6.3%) had severe malaria. Of the 1217 women admitted with malaria in the second and third trimesters without an impending adverse outcome, those treated with DHP were more likely to be discharged with an ongoing pregnancy compared to those treated with a non-ACT regimen (Odds Ratio OR = 2.48 [1.26–4.86]); p = 0.006. However in the first trimester 63% (5/8) of women treated with oral DHP miscarried compared to 2.6% (1/38) of those receiving oral quinine; p<0.001. Of the 847 women admitted for delivery those reporting a history of malaria during their pregnancy who had been treated with quinine-based regimens rather than DHP had a higher risk of malaria at delivery (adjusted OR = 1.56 (95%CI 0.97–2.5), p = 0.068) and perinatal mortality (adjusted OR = 3.17 [95%CI: 1.17–8.60]; p = 0.023). Conclusions In the second and third trimesters of pregnancy, a three day course of DHP simplified antimalarial treatment and had significant benefits over quinine-based regimens in reducing recurrent malaria and poor fetal outcome. These data provide reassuring evidence for the rational design of prospective randomized clinical trials and pharmacokinetic studies. PMID:24465458

  19. Absolute stability and Hopf bifurcation in a Plasmodium falciparum malaria model incorporating discrete immune response delay.

    PubMed

    Ncube, Israel

    2013-05-01

    We consider the absolute stability of the disease-free equilibrium of an intra-host Plasmodium falciparum malarial model allowing for antigenic variation within a single species. Antigenic variation can be viewed as an adaptation of the parasite to evade host defence [2]. The model was recently developed in [3-6]. The host's immune response is compartmentalised into reactions to major and minor epitopes. The immune response mounted by the human host is delayed, where, for simplicity, the delay is assumed to be discrete. We investigate the resulting characteristic equation, with a view to establishing absolute stability criteria and computing the Hopf bifurcation of the disease-free equilibrium.

  20. Evidence that a point mutation in dihydrofolate reductase-thymidylate synthase confers resistance to pyrimethamine in falciparum malaria.

    PubMed Central

    Peterson, D S; Walliker, D; Wellems, T E

    1988-01-01

    Analysis of a genetic cross of Plasmodium falciparum and of independent parasite isolates from Southeast Asia, Africa, and South America indicates that resistance to pyrimethamine, an antifolate used in the treatment of malaria, results from point mutations in the gene encoding dihydrofolate reductase-thymidylate synthase (EC 1.5.1.3 and EC 2.1.1.45, respectively). Parasites having a mutation from Thr-108/Ser-108 to Asn-108 in DHFR-TS are resistant to the drug. The Asn-108 mutation occurs in a region analogous to the C alpha-helix bordering the active site cavity of bacterial, avian, and mammalian enzymes. Additional point mutations (Asn-51 to Ile-51 and Cys-59 to Arg-59) are associated with increased pyrimethamine resistance and also occur at sites expected to border the active site cavity. Analogies with known inhibitor/enzyme structures from other organisms suggest that the point mutations occur where pyrimethamine contacts the enzyme and may act by inhibiting binding of the drug. Images PMID:2904149

  1. Recombinant plasmepsin 1 from the human malaria parasite Plasmodium falciparum: Enzymatic characterization, active site inhibitor design, and structural analysis

    PubMed Central

    Liu, Peng; Marzahn, Melissa R.; Robbins, Arthur H.; Gutiérrez-de-Terán, Hugo; Rodríguez, David; McClung, Scott; Stevens, Stanley M.; Yowell, Charles A.; Dame, John B.; McKenna, Robert; Dunn, Ben M.

    2009-01-01

    A mutated form of truncated proplasmepsin 1 (proPfPM1) from the human malaria parasite Plasmodium falciparum, proPfPM1 K110pN, was generated and overexpressed in E. coli. The auto-maturation process was carried out at pH 4.0 and 4.5, and the optimal catalytic pH of the resulting mature PfPM1 was determined to be pH 5.5. This mature PfPM1 showed comparable binding affinity to peptide substrates and inhibitors with the naturally-occurring form isolated from parasites. The S3-S3’ subsite preferences of the recombinant mature PfPM1 were explored using combinatorial chemistry based peptide libraries. Based on the results, a peptidomimetic inhibitor (compound 1) was designed and yielded 5-fold selectivity for binding to PfPM1 versus the homologous human cathepsin D (hcatD). The 2.8 Å structure of the PfPMP2-compound 1 complex is reported. Modeling studies were conducted using a series of peptidomimetic inhibitors (compounds 1–6, Table 3) and three plasmepsins: the crystal structure of PfPM2, and homology derived models of PfPM1 and PfPM4. PMID:19271776

  2. Inhibition of Plasmodium falciparum proliferation in vitro by double-stranded RNA directed against malaria histone deacetylase

    SciTech Connect

    Sriwilaijaroen, N.; Boonma, S.; Attasart, P.; Pothikasikorn, J.; Panyim, S.; Noonpakdee, W.

    2009-04-03

    Acetylation and deacetylation of histones play important roles in transcription regulation, cell cycle progression and development events. The steady state status of histone acetylation is controlled by a dynamic equilibrium between competing histone acetylase and deacetylase (HDAC). We have used long PfHDAC-1 double-stranded (ds)RNA to interfere with its cognate mRNA expression and determined the effect on malaria parasite growth and development. Chloroquine- and pyrimethamine-resistant Plasmodium falciparum K1 strain was exposed to 1-25 {mu}g of dsRNA/ml of culture for 48 h and growth was determined by [{sup 3}H]-hypoxanthine incorporation and microscopic examination. Parasite culture treated with 10 {mu}g/ml pfHDAC-1 dsRNA exhibited 47% growth inhibition when compared with either untreated control or culture treated with an unrelated dsRNA. PfHDAC-1 dsRNA specifically blocked maturation of trophozoite to schizont stages and decreased PfHDAC-1 transcript 44% in treated trophozoites. These results indicate the potential of HDAC-1 as a target for development of novel antimalarials.

  3. Neutral sphingomyelinase activity dependent on Mg2+ and anionic phospholipids in the intraerythrocytic malaria parasite Plasmodium falciparum.

    PubMed Central

    Hanada, K; Mitamura, T; Fukasawa, M; Magistrado, P A; Horii, T; Nishijima, M

    2000-01-01

    Sphingolipid metabolism and metabolites are important in various cellular events in eukaryotes. However, little is known about their function in plasmodial parasites. Here we demonstrate that neutral sphingomyelinase (SMase) involved in the sphingomyelin (SM) catabolism is retained by the intraerythrocytic parasite Plasmodium falciparum. When assayed in a neutral pH buffer supplemented with Mg(2+) and phosphatidylserine, an activity for the release of the phosphocholine group from SM was detected in parasite-infected, but not in uninfected, erythrocyte ghosts. The SMase activity in the parasite-infected erythrocyte ghosts was enhanced markedly by anionic phospholipids including unsaturated but not saturated phosphatidylserine. Mn(2+) could not substitute for Mg(2+) to activate SMase in parasite-infected erythrocyte ghosts, whereas both Mn(2+) and Mg(2+) activated mammalian neutral SMase. The specific activity level of SMase was higher in isolated parasites than in infected erythrocyte ghosts; further fractionation of lysates of the isolated parasites showed that the activity was bound largely to the membrane fraction of the parasites. The plasmodial SMase seemed not to hydrolyse phosphatidylcholine or phosphatidylinositol. The plasmodial SMase, but not SM synthase, was sensitive to scyphostatin, an inhibitor of mammalian neutral SMase, indicating that the plasmodial activities for SM hydrolysis and SM synthesis are mediated by different catalysts. Our finding that the malaria parasites possess SMase activity might explain why the parasites seem to have an SM synthase activity but no activity to synthesize ceramide de novo. PMID:10698693

  4. Regulatory Elements within the Prodomain of Falcipain-2, a Cysteine Protease of the Malaria Parasite Plasmodium falciparum

    PubMed Central

    Pandey, Kailash C.; Barkan, David T.; Sali, Andrej; Rosenthal, Philip J.

    2009-01-01

    Falcipain-2, a papain family cysteine protease of the malaria parasite Plasmodium falciparum, plays a key role in parasite hydrolysis of hemoglobin and is a potential chemotherapeutic target. As with many proteases, falcipain-2 is synthesized as a zymogen, and the prodomain inhibits activity of the mature enzyme. To investigate the mechanism of regulation of falcipain-2 by its prodomain, we expressed constructs encoding different portions of the prodomain and tested their ability to inhibit recombinant mature falcipain-2. We identified a C-terminal segment (Leu155–Asp243) of the prodomain, including two motifs (ERFNIN and GNFD) that are conserved in cathepsin L sub-family papain family proteases, as the mediator of prodomain inhibitory activity. Circular dichroism analysis showed that the prodomain including the C-terminal segment, but not constructs lacking this segment, was rich in secondary structure, suggesting that the segment plays a crucial role in protein folding. The falcipain-2 prodomain also efficiently inhibited other papain family proteases, including cathepsin K, cathepsin L, cathepsin B, and cruzain, but it did not inhibit cathepsin C or tested proteases of other classes. A structural model of pro-falcipain-2 was constructed by homology modeling based on crystallographic structures of mature falcipain-2, procathepsin K, procathepsin L, and procaricain, offering insights into the nature of the interaction between the prodomain and mature domain of falcipain-2 as well as into the broad specificity of inhibitory activity of the falcipain-2 prodomain. PMID:19479029

  5. Pulmonary pathology in pediatric cerebral malaria.

    PubMed

    Milner, Danny; Factor, Rachel; Whitten, Rich; Carr, Richard A; Kamiza, Steve; Pinkus, Geraldine; Molyneux, Malcolm; Taylor, Terrie

    2013-12-01

    Respiratory signs are common in African children where malaria is highly endemic, and thus, parsing the role of pulmonary pathology in illness is challenging. We examined the lungs of 100 children from an autopsy series in Blantyre, Malawi, many of whom death was attributed to Plasmodium falciparum malaria. Our aim was to describe the pathologic manifestations of fatal malaria; to understand the role of parasites, pigment, and macrophages; and to catalog comorbidities. From available patients, which included 55 patients with cerebral malaria and 45 controls, we obtained 4 cores of lung tissue for immunohistochemistry and morphological evaluation. We found that, in patients