Label-free microfluidic enrichment of ring-stage Plasmodium falciparum-infected red blood cells using non-inertial hydrodynamic lift.

PubMed

Geislinger, Thomas M; Chan, Sherwin; Moll, Kirsten; Wixforth, Achim; Wahlgren, Mats; Franke, Thomas

2014-09-20

Understanding of malaria pathogenesis caused by Plasmodium falciparum has been greatly deepened since the introduction of in vitro culture system, but the lack of a method to enrich ring-stage parasites remains a technical challenge. Here, a novel way to enrich red blood cells containing parasites in the early ring stage is described and demonstrated. A simple, straight polydimethylsiloxane microchannel connected to two syringe pumps for sample injection and two height reservoirs for sample collection is used to enrich red blood cells containing parasites in the early ring stage (8-10 h p.i.). The separation is based on the non-inertial hydrodynamic lift effect, a repulsive cell-wall interaction that enables continuous and label-free separation with deformability as intrinsic marker. The possibility to enrich red blood cells containing P. falciparum parasites at ring stage with a throughput of ~12,000 cells per hour and an average enrichment factor of 4.3 ± 0.5 is demonstrated. The method allows for the enrichment of red blood cells early after the invasion by P. falciparum parasites continuously and without any need to label the cells. The approach promises new possibilities to increase the sensitivity of downstream analyses like genomic- or diagnostic tests. The device can be produced as a cheap, disposable chip with mass production technologies and works without expensive peripheral equipment. This makes the approach interesting for the development of new devices for field use in resource poor settings and environments, e.g. with the aim to increase the sensitivity of microscope malaria diagnosis.

Cerebral malaria in mice: demonstration of cytoadherence of infected red blood cells and microrheologic correlates.

PubMed

Kaul, D K; Nagel, R L; Llena, J F; Shear, H L

1994-04-01

To understand the microcirculatory events during cerebral malaria, we have studied the lethal strain of rodent Plasmodia, Plasmodium yoelii 17XL, originally described by Yoeli and Hargreaves in 1974. The virulence of P. yoelii 17XL is caused by intravascular sequestration of infected red blood cells (IRBCs), especially in the brain vessels and capillaries. This mouse model resembles human P. falciparum infection more closely than P. berghei ANKA infection since it shows little, if any, inflammation of the brain. In vivo microcirculatory studies on cytoadherence of IRBCs were performed using the cremaster muscle preparation, which is an easily accessible vasculature for intravital observations. Ex vivo assay of cytoadherence was carried out in the artificially perfused mesocecum preparation of the rat. The results in either preparation demonstrated cytoadherence of IRBCs that was restricted to postcapillary venules. Furthermore, the in vivo measurements showed the prevalence of cytoadherence in small-diameter (< 40 microns) venules in accordance with the local wall shear rates. The parasitized animals demonstrated significantly reduced red blood cell velocities and wall shear rates in the small-diameter postcapillary venules of the cremaster. The relationship between cytoadherence and venular wall shear rates was also reflected in the inverse correlation between the number of adhered cells and the venular diameter in the ex vivo mesocecum preparation. In the ex vivo preparation, cytoadherence of IRBCs was accompanied by a higher peripheral resistance. Transmission electron microscopy of the cremaster muscle and brain tissues showed a tight association of IRBCs with the endothelium of small venules. These observations demonstrate that cytoadherence of P. yoelii 17XL-infected mouse red blood cells is very similar to that of P. falciparum-infected cells. Thus, this model should allow a detailed analysis of the molecular mechanisms involved in the generation of cerebral

Mature parasite-infected erythrocyte surface antigen (MESA) of Plasmodium falciparum binds to the 30-kDa domain of protein 4.1 in malaria-infected red blood cells.

PubMed

Waller, Karena L; Nunomura, Wataru; An, Xiuli; Cooke, Brian M; Mohandas, Narla; Coppel, Ross L

2003-09-01

The Plasmodium falciparum mature parasite-infected erythrocyte surface antigen (MESA) is exported from the parasite to the infected red blood cell (IRBC) membrane skeleton, where it binds to protein 4.1 (4.1R) via a 19-residue MESA sequence. Using purified RBC 4.1R and recombinant 4.1R fragments, we show MESA binds the 30-kDa region of RBC 4.1R, specifically to a 51-residue region encoded by exon 10 of the 4.1R gene. The 3D structure of this region reveals that the MESA binding site overlaps the region of 4.1R involved in the p55, glycophorin C, and 4.1R ternary complex. Further binding studies using p55, 4.1R, and MESA showed competition between p55 and MESA for 4.1R, implying that MESA bound at the IRBC membrane skeleton may modulate normal 4.1R and p55 interactions in vivo. Definition of minimal binding domains involved in critical protein interactions in IRBCs may aid the development of novel therapies for falciparum malaria.

Absence of Plasmodium inui and Plasmodium cynomolgi, but detection of Plasmodium knowlesi and Plasmodium vivax infections in asymptomatic humans in the Betong division of Sarawak, Malaysian Borneo.

PubMed

Siner, Angela; Liew, Sze-Tze; Kadir, Khamisah Abdul; Mohamad, Dayang Shuaisah Awang; Thomas, Felicia Kavita; Zulkarnaen, Mohammad; Singh, Balbir

2017-10-17

Plasmodium knowlesi, a simian malaria parasite, has become the main cause of malaria in Sarawak, Malaysian Borneo. Epidemiological data on malaria for Sarawak has been derived solely from hospitalized patients, and more accurate epidemiological data on malaria is necessary. Therefore, a longitudinal study of communities affected by knowlesi malaria was undertaken. A total of 3002 blood samples on filter paper were collected from 555 inhabitants of 8 longhouses with recently reported knowlesi malaria cases in the Betong Division of Sarawak, Malaysian Borneo. Each longhouse was visited bimonthly for a total of 10 times during a 21-month study period (Jan 2014-Oct 2015). DNA extracted from blood spots were examined by a nested PCR assay for Plasmodium and positive samples were then examined by nested PCR assays for Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, Plasmodium knowlesi, Plasmodium cynomolgi and Plasmodium inui. Blood films of samples positive by PCR were also examined by microscopy. Genus-specific PCR assay detected Plasmodium DNA in 9 out of 3002 samples. Species-specific PCR identified 7 P. knowlesi and one P. vivax. Malaria parasites were observed in 5 thick blood films of the PCR positive samples. No parasites were observed in blood films from one knowlesi-, one vivax- and the genus-positive samples. Only one of 7 P. knowlesi-infected individual was febrile and had sought medical treatment at Betong Hospital the day after sampling. The 6 knowlesi-, one vivax- and one Plasmodium-infected individuals were afebrile and did not seek any medical treatment. Asymptomatic human P. knowlesi and P. vivax malaria infections, but not P. cynomolgi and P. inui infections, are occurring within communities affected with malaria.

Towards a needle-free diagnosis of malaria: in vivo identification and classification of red and white blood cells containing haemozoin.

PubMed

Burnett, Jennifer L; Carns, Jennifer L; Richards-Kortum, Rebecca

2017-11-07

Optical detection of circulating haemozoin has been suggested as a needle free method to diagnose malaria using in vivo microscopy. Haemozoin is generated within infected red blood cells by the malaria parasite, serving as a highly specific, endogenous biomarker of malaria. However, phagocytosis of haemozoin by white blood cells which persist after the infection is resolved presents the potential for false positive diagnosis; therefore, the focus of this work is to identify a feature of the haemozoin signal to discriminate between infected red blood cells and haemozoin-containing white blood cells. Conventional brightfield microscopy of thin film blood smears was used to analyse haemozoin absorbance signal in vitro. Cell type and parasite maturity were morphologically determined using colocalized DAPI staining. The ability of features to discriminate between infected red blood cells and haemozoin-containing white blood cells was evaluated using images of smears from subjects infected with two species of Plasmodium, Plasmodium yoelii and Plasmodium falciparum. Discriminating features identified by blood smear microscopy were characterized in vivo in P. yoelii-infected mice. Two features of the haemozoin signal, haemozoin diameter and normalized intensity difference, were identified as potential parameters to differentiate infected red blood cells and haemozoin-containing white blood cells. Classification performance was evaluated using the area under the receiver operating characteristic curve, with area under the curve values of 0.89 for the diameter parameter and 0.85 for the intensity parameter when assessed in P. yoelii samples. Similar results were obtained from P. falciparum blood smears, showing an AUC of 0.93 or greater for both classification features. For in vivo investigations, the intensity-based metric was the best classifier, with an AUC of 0.91. This work demonstrates that size and intensity features of haemozoin absorbance signal collected by in vivo

Characterization of blood dendritic and regulatory T cells in asymptomatic adults with sub-microscopic Plasmodium falciparum or Plasmodium vivax infection.

PubMed

Kho, Steven; Marfurt, Jutta; Handayuni, Irene; Pava, Zuleima; Noviyanti, Rintis; Kusuma, Andreas; Piera, Kim A; Burdam, Faustina H; Kenangalem, Enny; Lampah, Daniel A; Engwerda, Christian R; Poespoprodjo, Jeanne R; Price, Ric N; Anstey, Nicholas M; Minigo, Gabriela; Woodberry, Tonia

2016-06-21

Plasmodium falciparum and Plasmodium vivax infections compromise dendritic cell (DC) function and expand regulatory T (Treg) cells in both clinical disease (malaria) and experimental human sub-microscopic infection. Conversely, in asymptomatic microscopy-positive (patent) P. falciparum or P. vivax infection in endemic areas, blood DC increase or retain HLA-DR expression and Treg cells exhibit reduced activation, suggesting that DC and Treg cells contribute to the control of patent asymptomatic infection. The effect of sub-microscopic (sub-patent) asymptomatic Plasmodium infection on DC and Treg cells in malaria-endemic area residents remains unclear. In a cross-sectional household survey conducted in Papua, Indonesia, 162 asymptomatic adults were prospectively evaluated for DC and Treg cells using field-based flow cytometry. Of these, 161 individuals (99 %) were assessed retrospectively by polymerase chain reaction (PCR), 19 of whom had sub-microscopic infection with P. falciparum and 15 with sub-microscopic P. vivax infection. Flow cytometric data were re-analysed after re-grouping asymptomatic individuals according to PCR results into negative controls, sub-microscopic and microscopic parasitaemia to examine DC and Treg cell phenotype in sub-microscopic infection. Asymptomatic adults with sub-microscopic P. falciparum or P. vivax infection had DC HLA-DR expression and Treg cell activation comparable to PCR-negative controls. Sub-microscopic P. falciparum infection was associated with lower peripheral CD4(+) T cells and lymphocytes, however sub-microscopic Plasmodium infection had no apparent effect on DC sub-set number or Treg cell frequency. In contrast to the impairment of DC maturation/function and the activation of Treg cells seen with sub-microscopic parasitaemia in primary experimental human Plasmodium infection, no phenotypic evidence of dysregulation of DC and Treg cells was observed in asymptomatic sub-microscopic Plasmodium infection in Indonesian

Plasmodium knowlesi from archival blood films: Further evidence that human infections are widely distributed and not newly emergent in Malaysian Borneo

PubMed Central

Lee, Kim-Sung; Cox-Singh, Janet; Brooke, George; Matusop, Asmad; Singh, Balbir

2009-01-01

Human infections with Plasmodium knowlesi have been misdiagnosed by microscopy as Plasmodium malariae due to their morphological similarities. Although microscopy-identified P. malariae cases have been reported in the state of Sarawak (Malaysian Borno) as early as 1952, recent epidemiological studies suggest the absence of indigenous P. malariae infections. The present study aimed to determine the past incidence and distribution of P. knowlesi infections in the state of Sarawak based on archival blood films from patients diagnosed by microscopy as having P. malariae infections. Nested PCR assays were used to identify Plasmodium species in DNA extracted from 47 thick blood films collected in 1996 from patients in seven different divisions throughout the state of Sarawak. Plasmodium knowlesi DNA was detected in 35 (97.2%) of 36 blood films that were positive for Plasmodium DNA, with patients originating from all seven divisions. Only one sample was positive for P. malariae DNA. This study provides further evidence of the widespread distribution of human infections with P. knowlesi in Sarawak and its past occurrence. Taken together with data from previous studies, our findings suggest that P. knowlesi malaria is not a newly emergent disease in humans. PMID:19358848

ABO Blood Groups Influence Macrophage-mediated Phagocytosis of Plasmodium falciparum-infected Erythrocytes

PubMed Central

Branch, Donald R.; Hult, Annika K.; Olsson, Martin L.; Liles, W. Conrad; Cserti-Gazdewich, Christine M.; Kain, Kevin C.

2012-01-01

Erythrocyte polymorphisms associated with a survival advantage to Plasmodium falciparum infection have undergone positive selection. There is a predominance of blood group O in malaria-endemic regions, and several lines of evidence suggest that ABO blood groups may influence the outcome of P. falciparum infection. Based on the hypothesis that enhanced innate clearance of infected polymorphic erythrocytes is associated with protection from severe malaria, we investigated whether P. falciparum-infected O erythrocytes are more efficiently cleared by macrophages than infected A and B erythrocytes. We show that human macrophages in vitro and mouse monocytes in vivo phagocytose P. falciparum-infected O erythrocytes more avidly than infected A and B erythrocytes and that uptake is associated with increased hemichrome deposition and high molecular weight band 3 aggregates in infected O erythrocytes. Using infected A1, A2, and O erythrocytes, we demonstrate an inverse association of phagocytic capacity with the amount of A antigen on the surface of infected erythrocytes. Finally, we report that enzymatic conversion of B erythrocytes to type as O before infection significantly enhances their uptake by macrophages to observed level comparable to that with infected O wild-type erythrocytes. These data provide the first evidence that ABO blood group antigens influence macrophage clearance of P. falciparum-infected erythrocytes and suggest an additional mechanism by which blood group O may confer resistance to severe malaria. PMID:23071435

Quantitative non-invasive intracellular imaging of Plasmodium falciparum infected human erythrocytes

NASA Astrophysics Data System (ADS)

Edward, Kert; Farahi, Faramarz

2014-05-01

Malaria is a virulent pathological condition which results in over a million annual deaths. The parasitic agent Plasmodium falciparum has been extensively studied in connection with this epidemic but much remains unknown about its development inside the red blood cell host. Optical and fluorescence imaging are among the two most common procedures for investigating infected erythrocytes but both require the introduction of exogenous contrast agents. In this letter, we present a procedure for the non-invasive in situ imaging of malaria infected red blood cells. The procedure is based on the utilization of simultaneously acquired quantitative phase and independent topography data to extract intracellular information. Our method allows for the identification of the developmental stages of the parasite and facilitates in situ analysis of the morphological changes associated with the progression of this disease. This information may assist in the development of efficacious treatment therapies for this condition.

A systematic review: Performance of RDTs for the detection of Plasmodium knowlesi, Plasmodium malariae, and Plasmodium ovale mono-infections in human blood.

PubMed

Yerlikaya, Seda; Campillo, Ana; Gonzalez, Iveth J

2018-03-15

Despite the increased use and worldwide distribution of malaria rapid diagnostic tests (RDTs) which distinguish between Plasmodium falciparum and non-falciparum species, little is known about their performance for detecting Plasmodium knowlesi (Pk), Plasmodium malariae (Pm), and Plasmodium ovale (Po). The objective of this review is to analyze results of published studies evaluating the diagnostic accuracy of malaria RDTs in detecting Pk, Pm and Po mono-infections.MEDLINE, EMBASE, Web of Science and CENTRAL databases were systematically searched to identify studies which reported on the performance of RDTs in detecting Pk, Pm,Po mono-infections.Among 40 studies included in the review, three reported on Pk, eight on Pm, five on Po, one on Pk and Pm, and 23 on Pm and Po infections. In the meta-analysis, estimates of sensitivities of RDTs in detecting Pk infections ranged from 2% to 48%. Test performances for Pm and Po infections were less accurate and highly heterogeneous, mainly due to the small number of samples tested.Limited data available suggest that malaria RDTs show suboptimal performance for detecting Pk, Pm,Po infections. New improved RDTs as well as appropriately designed, cross-sectional studies to demonstrate their usefulness in the detection of neglected Plasmodium species, are urgently needed.

CD8+ T Cells and IFN-γ Mediate the Time-Dependent Accumulation of Infected Red Blood Cells in Deep Organs during Experimental Cerebral Malaria

PubMed Central

Claser, Carla; Malleret, Benoît; Gun, Sin Yee; Wong, Alicia Yoke Wei; Chang, Zi Wei; Teo, Pearline; See, Peter Chi Ee; Howland, Shanshan Wu; Ginhoux, Florent; Rénia, Laurent

2011-01-01

Background Infection with Plasmodium berghei ANKA (PbA) in susceptible mice induces a syndrome called experimental cerebral malaria (ECM) with severe pathologies occurring in various mouse organs. Immune mediators such as T cells or cytokines have been implicated in the pathogenesis of ECM. Red blood cells infected with PbA parasites have been shown to accumulate in the brain and other tissues during infection. This accumulation is thought to be involved in PbA–induced pathologies, which mechanisms are poorly understood. Methods and Findings Using transgenic PbA parasites expressing the luciferase protein, we have assessed by real-time in vivo imaging the dynamic and temporal contribution of different immune factors in infected red blood cell (IRBC) accumulation and distribution in different organs during PbA infection. Using deficient mice or depleting antibodies, we observed that CD8+ T cells and IFN-γ drive the rapid increase in total parasite biomass and accumulation of IRBC in the brain and in different organs 6–12 days post-infection, at a time when mice develop ECM. Other cells types like CD4+ T cells, monocytes or neutrophils or cytokines such as IL-12 and TNF-α did not influence the early increase of total parasite biomass and IRBC accumulation in different organs. Conclusions CD8+ T cells and IFN-γ are the major immune mediators controlling the time-dependent accumulation of P. berghei-infected red blood cells in tissues. PMID:21494565

New insights into host-parasite ubiquitin proteome dynamics in P. falciparum infected red blood cells using a TUBEs-MS approach.

PubMed

Mata-Cantero, Lydia; Azkargorta, Mikel; Aillet, Fabienne; Xolalpa, Wendy; LaFuente, Maria J; Elortza, Felix; Carvalho, Ana Sofia; Martin-Plaza, Julio; Matthiesen, Rune; Rodriguez, Manuel S

2016-04-29

Malaria, caused by Plasmodium falciparum (P. falciparum), ranks as one of the most baleful infectious diseases worldwide. New antimalarial treatments are needed to face existing or emerging drug resistant strains. Protein degradation appears to play a significant role during the asexual intraerythrocytic developmental cycle (IDC) of P. falciparum. Inhibition of the ubiquitin proteasome system (UPS), a major intracellular proteolytic pathway, effectively reduces infection and parasite replication. P. falciparum and erythrocyte UPS coexist during IDC but the nature of their relationship is largely unknown. We used an approach based on Tandem Ubiquitin-Binding Entities (TUBEs) and 1D gel electrophoresis followed by mass spectrometry to identify major components of the TUBEs-associated ubiquitin proteome of both host and parasite during ring, trophozoite and schizont stages. Ring-exported protein (REX1), a P. falciparum protein located in Maurer's clefts and important for parasite nutrient import, was found to reach a maximum level of ubiquitylation in trophozoites stage. The Homo sapiens (H. sapiens) TUBEs associated ubiquitin proteome decreased during the infection, whereas the equivalent P. falciparum TUBEs-associated ubiquitin proteome counterpart increased. Major cellular processes such as DNA repair, replication, stress response, vesicular transport and catabolic events appear to be regulated by ubiquitylation along the IDC P. falciparum infection. In this work we analyze for the first time the interconnection between Plasmodium and human red blood cells ubiquitin-regulated proteins in the context of infection. We identified a number of human and Plasmodium proteins whose ubiquitylation pattern changes during the asexual infective stage. We demonstrate that ubiquitylation of REX1, a P. falciparum protein located in Maurer's clefts and important for parasite nutrient import, peaks in trophozoites stage. The ubiquitin-proteome from P. falciparum infected red blood

Prevalence and distribution of human Plasmodium infection in Pakistan.

PubMed

Khattak, Aamer A; Venkatesan, Meera; Nadeem, Muhammad F; Satti, Humayoon S; Yaqoob, Adnan; Strauss, Kathy; Khatoon, Lubna; Malik, Salman A; Plowe, Christopher V

2013-08-28

Both Plasmodium vivax and Plasmodium falciparum are prevalent in Pakistan, yet up-to-date data on the epidemiology of malaria in Pakistan are not available. This study was undertaken to determine the current prevalence and distribution of Plasmodium species across the country. A malariometric population survey was conducted in 2011 using blood samples collected from 801 febrile patients of all ages in four provinces and the capital city of Islamabad. Microscopically confirmed Plasmodium-positive blood samples were reconfirmed by polymerase chain reaction (PCR). Confirmed parasite-positive samples were subjected to species-specific PCR capable of detecting four species of human malaria. Of the 707 PCR-positive samples, 128 (18%) were P. falciparum, 536 (76%) were P. vivax, and 43 (6%) were mixed P. falciparum and P. vivax. Ninety-four microscopy-positive samples were PCR-negative, and Plasmodium malariae and Plasmodium ovale were not detected. Prevalence of P. vivax ranged from 2.4% in Punjab Province to 10.8% in Sindh Province and prevalence of P. falciparum ranged from 0.1% in Islamabad to 3.8% in Balochistan. Plasmodium infections in Pakistan are largely attributed to P. vivax but P. falciparum and mixed species infections are also prevalent. In addition, regional variation in the prevalence and species composition of malaria is high.

Strain-specific spleen remodelling in Plasmodium yoelii infections in Balb/c mice facilitates adherence and spleen macrophage-clearance escape

PubMed Central

Martin-Jaular, Lorena; Ferrer, Mireia; Calvo, Maria; Rosanas-Urgell, Anna; Kalko, Susana; Graewe, Stefanie; Soria, Guadalupe; Cortadellas, Núria; Ordi, Jaume; Planas, Anna; Burns, James; Heussler, Volker; del Portillo, Hernando A

2011-01-01

Knowledge of the dynamic features of the processes driven by malaria parasites in the spleen is lacking. To gain insight into the function and structure of the spleen in malaria, we have implemented intravital microscopy and magnetic resonance imaging of the mouse spleen in experimental infections with non-lethal (17X) and lethal (17XL) Plasmodium yoelii strains. Noticeably, there was higher parasite accumulation, reduced motility, loss of directionality, increased residence time and altered magnetic resonance only in the spleens of mice infected with 17X. Moreover, these differences were associated with the formation of a strain-specific induced spleen tissue barrier of fibroblastic origin, with red pulp macrophage-clearance evasion and with adherence of infected red blood cells to this barrier. Our data suggest that in this reticulocyte-prone non-lethal rodent malaria model, passage through the spleen is different from what is known in other Plasmodium species and open new avenues for functional/structural studies of this lymphoid organ in malaria. PMID:20923452

Prevalence and distribution of human Plasmodium infection in Pakistan

PubMed Central

2013-01-01

Background Both Plasmodium vivax and Plasmodium falciparum are prevalent in Pakistan, yet up-to-date data on the epidemiology of malaria in Pakistan are not available. This study was undertaken to determine the current prevalence and distribution of Plasmodium species across the country. Methods A malariometric population survey was conducted in 2011 using blood samples collected from 801 febrile patients of all ages in four provinces and the capital city of Islamabad. Microscopically confirmed Plasmodium-positive blood samples were reconfirmed by polymerase chain reaction (PCR). Confirmed parasite-positive samples were subjected to species-specific PCR capable of detecting four species of human malaria. Results Of the 707 PCR-positive samples, 128 (18%) were P. falciparum, 536 (76%) were P. vivax, and 43 (6%) were mixed P. falciparum and P. vivax. Ninety-four microscopy-positive samples were PCR-negative, and Plasmodium malariae and Plasmodium ovale were not detected. Prevalence of P. vivax ranged from 2.4% in Punjab Province to 10.8% in Sindh Province and prevalence of P. falciparum ranged from 0.1% in Islamabad to 3.8% in Balochistan. Conclusions Plasmodium infections in Pakistan are largely attributed to P. vivax but P. falciparum and mixed species infections are also prevalent. In addition, regional variation in the prevalence and species composition of malaria is high. PMID:23984968

Avian malaria co-infections confound infectivity and vector competence assays of Plasmodium homopolare.

PubMed

Carlson, Jenny S; Nelms, Brittany; Barker, Christopher M; Reisen, William K; Sehgal, Ravinder N M; Cornel, Anthony J

2018-05-29

Currently, there are very few studies of avian malaria that investigate relationships among the host-vector-parasite triad concomitantly. In the current study, we experimentally measured the vector competence of several Culex mosquitoes for a newly described avian malaria parasite, Plasmodium homopolare. Song sparrow (Melospiza melodia) blood infected with a low P. homopolare parasitemia was inoculated into a naïve domestic canary (Serinus canaria forma domestica). Within 5 to 10 days post infection (dpi), the canary unexpectedly developed a simultaneous high parasitemic infection of Plasmodium cathemerium (Pcat6) and a low parasitemic infection of P. homopolare, both of which were detected in blood smears. During this infection period, PCR detected Pcat6, but not P. homopolare in the canary. Between 10 and 60 dpi, Pcat6 blood stages were no longer visible and PCR no longer amplified Pcat6 parasite DNA from canary blood. However, P. homopolare blood stages remained visible, albeit still at very low parasitemias, and PCR was able to amplify P. homopolare DNA. This pattern of mixed Pcat6 and P. homopolare infection was repeated in three secondary infected canaries that were injected with blood from the first infected canary. Mosquitoes that blood-fed on the secondary infected canaries developed infections with Pcat6 as well as another P. cathemerium lineage (Pcat8); none developed PCR detectable P. homopolare infections. These observations suggest that the original P. homopolare-infected songbird also had two un-detectable P. cathemerium lineages/strains. The vector and host infectivity trials in this study demonstrated that current molecular assays may significantly underreport the extent of mixed avian malaria infections in vectors and hosts.

Therapeutic PD-L1 and LAG-3 blockade rapidly clears established blood-stage Plasmodium infection

PubMed Central

Butler, Noah S.; Moebius, Jacqueline; Pewe, Lecia L.; Traore, Boubacar; Doumbo, Ogobara K.; Tygrett, Lorraine T.; Waldschmidt, Thomas J.; Crompton, Peter D.; Harty, John T.

2011-01-01

Plasmodium infection of erythrocytes induces clinical malaria. Parasite-specific CD4+ T cells correlate with reduced parasite burdens and severity of human malaria, and are required to control blood-stage infection in mice. However, the characteristics of CD4+ T cells that determine protection or parasite persistence remain unknown. Here we show that P. falciparum infection of humans increased expression of an inhibitory receptor (PD-1) associated with T cell dysfunction. In vivo blockade of PD-L1 and LAG-3 restored CD4+ T cell function, amplified T follicular helper cell and germinal center B cell and plasmablast numbers, enhanced protective antibodies and rapidly cleared blood-stage malaria in mice. Thus, chronic malaria drives specific T cell dysfunction, which can be rescued to enhance parasite control using inhibitory therapies. PMID:22157630

A Novel ENU-Mutation in Ankyrin-1 Disrupts Malaria Parasite Maturation in Red Blood Cells of Mice

PubMed Central

Greth, Andreas; Lampkin, Shelley; Mayura-Guru, Preethi; Rodda, Fleur; Drysdale, Karen; Roberts-Thomson, Meredith; McMorran, Brendan J.; Foote, Simon J.; Burgio, Gaétan

2012-01-01

The blood stage of the plasmodium parasite life cycle is responsible for the clinical symptoms of malaria. Epidemiological studies have identified coincidental malarial endemicity and multiple red blood cell (RBC) disorders. Many RBC disorders result from mutations in genes encoding cytoskeletal proteins and these are associated with increased protection against malarial infections. However the mechanisms underpinning these genetic, host responses remain obscure. We have performed an N-ethyl-N-nitrosourea (ENU) mutagenesis screen and have identified a novel dominant (haploinsufficient) mutation in the Ank-1 gene (Ank1MRI23420) of mice displaying hereditary spherocytosis (HS). Female mice, heterozygous for the Ank-1 mutation showed increased survival to infection by Plasmodium chabaudi adami DS with a concomitant 30% decrease in parasitemia compared to wild-type, isogenic mice (wt). A comparative in vivo red cell invasion and parasite growth assay showed a RBC-autonomous effect characterised by decreased proportion of infected heterozygous RBCs. Within approximately 6–8 hours post-invasion, TUNEL staining of intraerythrocytic parasites, showed a significant increase in dead parasites in heterozygotes. This was especially notable at the ring and trophozoite stages in the blood of infected heterozygous mutant mice compared to wt (p<0.05). We conclude that increased malaria resistance due to ankyrin-1 deficiency is caused by the intraerythrocytic death of P. chabaudi parasites. PMID:22723917

[Application of Nested PCR in the Diagnosis of Imported Plasmodium Ovale Infection].

PubMed

Huang, Bing-cheng; Xu, Chao; Li, Jin; Xiao, Ting; Yin, Kun; Liu, Gong-zhen; Wang, Wei-yan; Zhao, Gui-hua; Wei, Yan-bin; Wang, Yong-bin; Zhao, Chang-lei; Wei, Qing-kuan

2015-02-01

To identity Plasmodium ovale infection by 18S rRNA gene nested PCR. Whole blood and filter paper blood samples of malaria patients in Shandong Province were collected during 2012-2013. The parasites were observed under a microscope with Giemsa staining. The genome DNA of blood samples were extracted as PCR templates. Genus- and species-specific primers were designed according to the Plasmodium 18S rRNA gene sequences. Plasmodium ovale-positive specimens were identified by nested PCR as well as verified by sequencing. There were 7 imported cases of P. ovale infection in the province during 2012-2013. Nested PCR results showed that the P. ovale specific band (800 bp) was amplified in all the 7 specimens. Blast results indicated that the PCR products were consistent with the Plasmodium ovale reference sequence in GenBank. Seven imported cases of ovale malaria in Shandong Province in 2012-2013 are confirmed by nested PCR.

The persistence and oscillations of submicroscopic Plasmodium falciparum and Plasmodium vivax infections over time in Vietnam: an open cohort study.

PubMed

Nguyen, Thuy-Nhien; von Seidlein, Lorenz; Nguyen, Tuong-Vy; Truong, Phuc-Nhi; Hung, Son Do; Pham, Huong-Thu; Nguyen, Tam-Uyen; Le, Thanh Dong; Dao, Van Hue; Mukaka, Mavuto; Day, Nicholas Pj; White, Nicholas J; Dondorp, Arjen M; Thwaites, Guy E; Hien, Tran Tinh

2018-05-01

A substantial proportion of Plasmodium species infections are asymptomatic with densities too low to be detectable with standard diagnostic techniques. The importance of such asymptomatic plasmodium infections in malaria transmission is probably related to their duration and density. To explore the duration of asymptomatic plasmodium infections and changes in parasite densities over time, a cohort of participants who were infected with Plasmodium parasites was observed over a 2-year follow-up period. In this open cohort study, inhabitants of four villages in Vietnam were invited to participate in baseline and subsequent 3-monthly surveys up to 24 months, which included the collection of venous blood samples. Samples were batch-screened using ultra-sensitive (u)PCR (lower limit of detection of 22 parasites per mL). Participants found to be infected by uPCR during any of these surveys were invited to join a prospective cohort and provide monthly blood samples. We estimated the persistence of Plasmodium falciparum and Plasmodium vivax infections and changes in parasite densities over a study period of 24 months. Between Dec 1, 2013, and Jan 8, 2016, 356 villagers participated in between one and 22 surveys. These study participants underwent 4248 uPCR evaluations (11·9 tests per participant). 1874 (32%) of 4248 uPCR tests indicated a plasmodium infection; 679 (36%) of 1874 tests were P falciparum monoinfections, 507 (27%) were P vivax monoinfections, 463 (25%) were co-infections with P falciparum and P vivax, and 225 (12%) were indeterminate species of Plasmodium. The median duration of P falciparum infection was 2 months (IQR 1-3); after accounting for censoring, participants had a 20% chance of having parasitaemia for 4 months or longer. The median duration of P vivax infection was 6 months (3-9), and participants had a 59% chance of having parasitaemia for 4 months or longer. The parasite densities of persistent infections oscillated; following ultralow

Anopheles gambiae Circumsporozoite Protein–Binding Protein Facilitates Plasmodium Infection of Mosquito Salivary Glands

PubMed Central

Wang, Jiuling; Zhang, Yue; Zhao, Yang O.; Li, Michelle W. M.; Zhang, Lili; Dragovic, Srdjan; Abraham, Nabil M.; Fikrig, Erol

2013-01-01

Malaria, a mosquito-borne disease caused by Plasmodium species, causes substantial morbidity and mortality throughout the world. Plasmodium sporozoites mature in oocysts formed in the mosquito gut wall and then invade the salivary glands, where they remain until transmitted to the vertebrate host during a mosquito bite. The Plasmodium circumsporozoite protein (CSP) binds to salivary glands and plays a role in the invasion of this organ by sporozoites. We identified an Anopheles salivary gland protein, named CSP-binding protein (CSPBP), that interacts with CSP. Downregulation of CSPBP in mosquito salivary glands inhibited invasion by Plasmodium organisms. In vivo bioassays showed that mosquitoes that were fed blood with CSPBP antibody displayed a 25% and 90% reduction in the parasite load in infected salivary glands 14 and 18 days after the blood meal, respectively. These results suggest that CSPBP is important for the infection of the mosquito salivary gland by Plasmodium organisms and that blocking CSPBP can interfere with the Plasmodium life cycle. PMID:23801601

Identification of malaria parasite-infected red blood cell surface aptamers by inertial microfluidic SELEX (I-SELEX)

NASA Astrophysics Data System (ADS)

Birch, Christina M.; Hou, Han Wei; Han, Jongyoon; Niles, Jacquin C.

2015-07-01

Plasmodium falciparum malaria parasites invade and remodel human red blood cells (RBCs) by trafficking parasite-synthesized proteins to the RBC surface. While these proteins mediate interactions with host cells that contribute to disease pathogenesis, the infected RBC surface proteome remains poorly characterized. Here we use a novel strategy (I-SELEX) to discover high affinity aptamers that selectively recognize distinct epitopes uniquely present on parasite-infected RBCs. Based on inertial focusing in spiral microfluidic channels, I-SELEX enables stringent partitioning of cells (efficiency ≥ 106) from unbound oligonucleotides at high volume throughput (~2 × 106 cells min-1). Using an RBC model displaying a single, non-native antigen and live malaria parasite-infected RBCs as targets, we establish suitability of this strategy for de novo aptamer selections. We demonstrate recovery of a diverse set of aptamers that recognize distinct, surface-displayed epitopes on parasite-infected RBCs with nanomolar affinity, including an aptamer against the protein responsible for placental sequestration, var2CSA. These findings validate I-SELEX as a broadly applicable aptamer discovery platform that enables identification of new reagents for mapping the parasite-infected RBC surface proteome at higher molecular resolution to potentially contribute to malaria diagnostics, therapeutics and vaccine efforts.

Does Magnetic Field Affect Malaria Parasite Replication in Human Red Blood Cells?

NASA Technical Reports Server (NTRS)

Chanturiya, Alexandr N.; Glushakova, Svetlana; Yin, Dan; Zimmerberg, Joshua

2004-01-01

Digestion of red blood cell (RBC) hemoglobin by the malaria parasite results in the formation of paramagnetic hemazoin crystals inside the parasite body. A number of reports suggest that magnetic field interaction with hamazoin crystals significantly reduces the number of infected cells in culture, and thus magnetic field can be used to combat malaria. We studies the effects of magnetic filed on the Plasmodium falciparum asexual life cycle inside RBCs under various experimental conditions. No effect was found during prolonged exposure of infected RBCs to constant magnetic fields up to 6000 Gauss. Infected RBCs were also exposed, under temperature-controlled conditions, to oscillating magnetic fields with frequencies in the range of 500-20000 kHz, and field strength 30-600 Gauss. This exposure often changed the proportion of different parasite stages in treated culture compared to controls. However, no significant effect on parasitemia was observed in treated cultures. This result indicates that the magnetic field effect on Plasmodium falciparum is negligible, or that hypothetical negative and positive effects on different stages within one 48-hour compensate each other.

Quantifying the biophysical characteristics of Plasmodium-falciparum-parasitized red blood cells in microcirculation

PubMed Central

Fedosov, D. A.; Caswell, B.; Suresh, S.; Karniadakis, G. E.

2011-01-01

The pathogenicity of Plasmodium falciparum (Pf) malaria results from the stiffening of red blood cells (RBCs) and its ability to adhere to endothelial cells (cytoadherence). The dynamics of Pf-parasitized RBCs is studied by three-dimensional mesoscopic simulations of flow in cylindrical capillaries in order to predict the flow resistance enhancement at different parasitemia levels. In addition, the adhesive dynamics of Pf-RBCs is explored for various parameters revealing several types of cell dynamics such as firm adhesion, very slow slipping along the wall, and intermittent flipping. The parasite inside the RBC is modeled explicitly in order to capture phenomena such as “hindered tumbling” motion of the RBC and the sudden transition from firm RBC cytoadherence to flipping on the endothelial surface. These predictions are in quantitative agreement with recent experimental observations, and thus the three-dimensional modeling method presented here provides new capabilities for guiding and interpreting future in vitro and in vivo studies of malaria. PMID:21173269

Functional Antibodies against VAR2CSA in Nonpregnant Populations from Colombia Exposed to Plasmodium falciparum and Plasmodium vivax

PubMed Central

Doritchamou, Justin; Arango, Eliana M.; Cabrera, Ana; Arroyo, Maria Isabel; Kain, Kevin C.; Ndam, Nicaise Tuikue; Maestre, Amanda

2014-01-01

In pregnancy, parity-dependent immunity is observed in response to placental infection with Plasmodium falciparum. Antibodies recognize the surface antigen, VAR2CSA, expressed on infected red blood cells and inhibit cytoadherence to the placental tissue. In most settings of malaria endemicity, antibodies against VAR2CSA are predominantly observed in multigravid women and infrequently in men, children, and nulligravid women. However, in Colombia, we detected antibodies against multiple constructs of VAR2CSA among men and children with acute P. falciparum and Plasmodium vivax infection. The majority of men and children (>60%) had high levels of IgGs against three recombinant domains of VAR2CSA: DBL5ε, DBL3X, and ID1-ID2. Surprisingly, these antibodies were observed only in pregnant women, men, and children exposed either to P. falciparum or to P. vivax. Moreover, the anti-VAR2CSA antibodies are of high avidity and efficiently inhibit adherence of infected red blood cells to chondroitin sulfate A in vitro, suggesting that they are specific and functional. These unexpected results suggest that there may be genotypic or phenotypic differences in the parasites of this region or in the host response to either P. falciparum or P. vivax infection outside pregnancy. These findings may hold significant clinical relevance to the pathophysiology and outcome of malaria infections in this region. PMID:24686068

Wherever I may roam: protein and membrane trafficking in P. falciparum-infected red blood cells.

PubMed

Deponte, Marcel; Hoppe, Heinrich C; Lee, Marcus C S; Maier, Alexander G; Richard, Dave; Rug, Melanie; Spielmann, Tobias; Przyborski, Jude M

2012-12-01

Quite aside from its immense importance as a human pathogen, studies in recent years have brought to light the fact that the malaria parasite Plasmodium falciparum is an interesting eukaryotic model system to study protein trafficking. Studying parasite cell biology often reveals an overrepresentation of atypical cell biological features, possibly driven by the parasites' need to survive in an unusual biological niche. Malaria parasites possess uncommon cellular compartments to which protein traffic must be directed, including secretory organelles such as rhoptries and micronemes, a lysosome-like compartment referred to as the digestive vacuole and a complex (four membrane-bound) plastid, the apicoplast. In addition, the parasite must provide proteins to extracellular compartments and structures including the parasitophorous vacuole, the parasitophorous vacuolar membrane, the Maurer's clefts and both cytosol and plasma membrane of the host cell, the mature human red blood cell. Although some of these unusual destinations are possessed by other cell types, only Plasmodium parasites contain them all within one cell. Here we review what is known about protein and membrane transport in the P. falciparum-infected cell, highlighting novel features of these processes. A growing body of evidence suggests that this parasite is a real "box of tricks" with regards to protein traffic. Possibly, these tricks may be turned against the parasite by exploiting them as novel therapeutic targets. Copyright © 2012 Elsevier B.V. All rights reserved.

MAPK phosphotase 5 deficiency contributes to protection against blood-stage Plasmodium yoelii 17XL infection in mice.

PubMed

Cheng, Qianqian; Zhang, Qingfeng; Xu, Xindong; Yin, Lan; Sun, Lin; Lin, Xin; Dong, Chen; Pan, Weiqing

2014-04-15

Cell-mediated immunity plays a crucial role in the development of host resistance to asexual blood-stage malaria infection. However, little is known of the regulatory factors involved in this process. In this study, we investigated the impact of MAPK phosphotase 5 (MKP5) on protective immunity against a lethal Plasmodium yoelii 17XL blood-stage infection using MKP5 knockout C57BL/6 mice. Compared with wild-type control mice, MKP5 knockout mice developed significantly lower parasite burdens with prolonged survival times. We found that this phenomenon correlated with a rapid and strong IFN-γ-dependent cellular immune response during the acute phase of infection. Inactivation of IFN-γ by the administration of a neutralizing Ab significantly reduced the protective effects in MKP5 knockout mice. By analyzing IFN-γ production in innate and adaptive lymphocyte subsets, we observed that MKP5 deficiency specifically enhanced the IFN-γ response mediated by CD4+ T cells, which was attributable to the increased stimulatory capacity of splenic CD11c+ dendritic cells. Furthermore, following vaccination with whole blood-stage soluble plasmodial Ag, MKP5 knockout mice acquired strongly enhanced Ag-specific immune responses and a higher level of protection against subsequent P. yoelii 17XL challenge. Finally, we found the enhanced response mediated by MKP5 deficiency resulted in a lethal consequence in mice when infected with nonlethal P. yoelii 17XNL. Thus, our data indicate that MKP5 is a potential regulator of immune resistance against Plasmodium infection in mice, and that an understanding of the role of MKP5 in manipulating anti-malaria immunity may provide valuable information on the development of better control strategies for human malaria.

Persistence and immunogenicity of chemically attenuated blood stage Plasmodium falciparum in Aotus monkeys.

PubMed

De, Sai Lata; Stanisic, Danielle I; van Breda, Karin; Bellete, Bernadette; Harris, Ivor; McCallum, Fiona; Edstein, Michael D; Good, Michael F

2016-08-01

Malaria is a disease caused by a protozoan of the Plasmodium genus and results in 0.5-0.7million deaths per year. Increasing drug resistance of the parasite and insecticide resistance of mosquitoes necessitate alternative control measures. Numerous vaccine candidates have been identified but none have been able to induce robust, long-lived protection when evaluated in malaria endemic regions. Rodent studies have demonstrated that chemically attenuated blood stage parasites can persist at sub-patent levels and induce homologous and heterologous protection against malaria. Parasite-specific cellular responses were detected, with protection dependent on CD4+ T cells. To investigate this vaccine approach for Plasmodium falciparum, we characterised the persistence and immunogenicity of chemically attenuated P. falciparum FVO strain parasites (CAPs) in non-splenectomised Aotus nancymaae monkeys following administration of a single dose. Control monkeys received either normal red blood cells or wild-type parasites followed by drug treatment. Chemical attenuation was performed using tafuramycin A, which irreversibly binds to DNA. CAPs were detected in the peripheral blood for up to 2days following inoculation as determined by thick blood smears, and for up to 8days as determined by quantitative PCR. Parasite-specific IgG was not detected in monkeys that received CAPs; however, in vitro parasite-specific T cell proliferation was observed. Following challenge, the CAP monkeys developed an infection; however, one CAP monkey and the infection and drug-cure monkeys showed partial or complete resistance. These experiments lay the groundwork for further assessment of CAPs as a potential vaccine against malaria. Copyright © 2016 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

Gellan sulfate inhibits Plasmodium falciparum growth and invasion of red blood cells in vitro

PubMed Central

Recuenco, Frances Cagayat; Kobayashi, Kyousuke; Ishiwa, Akiko; Enomoto-Rogers, Yukiko; Fundador, Noreen Grace V.; Sugi, Tatsuki; Takemae, Hitoshi; Iwanaga, Tatsuya; Murakoshi, Fumi; Gong, Haiyan; Inomata, Atsuko; Horimoto, Taisuke; Iwata, Tadahisa; Kato, Kentaro

2014-01-01

Here, we assessed the sulfated derivative of the microbial polysaccharide gellan gum and derivatives of λ and κ-carrageenans for their ability to inhibit Plasmodium falciparum 3D7 and Dd2 growth and invasion of red blood cells in vitro. Growth inhibition was assessed by means of flow cytometry after a 96-h exposure to the inhibitors and invasion inhibition was assessed by counting ring parasites after a 20-h exposure to them. Gellan sulfate strongly inhibited invasion and modestly inhibited growth for both P. falciparum 3D7 and Dd2; both inhibitory effects exceeded those achieved with native gellan gum. The hydrolyzed λ-carrageenan and oversulfated κ-carrageenan were less inhibitory than their native forms. In vitro cytotoxicity and anticoagulation assays performed to determine the suitability of the modified polysaccharides for in vivo studies showed that our synthesized gellan sulfate had low cytotoxicity and anticoagulant activity. PMID:24740150

Characterization of malaria infected blood cells by scanning confocal laser and acoustic vector contrast microscopy

NASA Astrophysics Data System (ADS)

Ahmed Mohamed, E. T.; Schubert, S.; Gilberger, T. W.; Kamanyi, A., Jr.; Wannemacher, R.; Grill, W.

2006-03-01

Acoustic and optical multiple contrast microscopy has been employed in order to explore characterizable parameters of red blood cells, including cells infected by the parasite Plasmodium falciparum, in order to investigate cellular modifications caused by the infection and to identify possible detection schemes for disease monitoring. Imaging schemes were based on fluorescence, optical transmission, optical reflection, and amplitude and phase of ultrasound reflected from the cells. Contrast variations observed in acoustic microscopy, but not in optical microscopy, were tentatively ascribed to changes caused by the infection.

First case of a naturally acquired human infection with Plasmodium cynomolgi

PubMed Central

2014-01-01

Since 1960, a total of seven species of monkey malaria have been reported as transmissible to man by mosquito bite: Plasmodium cynomolgi, Plasmodium brasilianum, Plasmodium eylesi, Plasmodium knowlesi, Plasmodium inui, Plasmodium schwetzi and Plasmodium simium. With the exception of P. knowlesi, none of the other species has been found to infect humans in nature. In this report, it is described the first known case of a naturally acquired P. cynomolgi malaria in humans. The patient was a 39-year-old woman from a malaria-free area with no previous history of malaria or travel to endemic areas. Initially, malaria was diagnosed and identified as Plasmodium malariae/P. knowlesi by microscopy in the Terengganu State Health Department. Thick and thin blood films stained with 10% Giemsa were performed for microscopy examination. Molecular species identification was performed at the Institute for Medical Research (IMR, Malaysia) and in the Malaria & Emerging Parasitic Diseases Laboratory (MAPELAB, Spain) using different nested PCR methods. Microscopic re-examination in the IMR showed characteristics of Plasmodium vivax and was confirmed by a nested PCR assay developed by Snounou et al. Instead, a different PCR assay plus sequencing performed at the MAPELAB confirmed that the patient was infected with P. cynomolgi and not with P. vivax. This is the first report of human P. cynomolgi infection acquired in a natural way, but there might be more undiagnosed or misdiagnosed cases, since P. cynomolgi is morphologically indistinguishable from P. vivax, and one of the most used PCR methods for malaria infection detection may identify a P. cynomolgi infection as P. vivax. Simian Plasmodium species may routinely infect humans in Southeast Asia. New diagnostic methods are necessary to distinguish between the human and monkey malaria species. Further epidemiological studies, incriminating also the mosquito vector(s), must be performed to know the relevance of cynomolgi malaria and its

First case of a naturally acquired human infection with Plasmodium cynomolgi.

PubMed

Ta, Thuy H; Hisam, Shamilah; Lanza, Marta; Jiram, Adela I; Ismail, NorParina; Rubio, José M

2014-02-24

Since 1960, a total of seven species of monkey malaria have been reported as transmissible to man by mosquito bite: Plasmodium cynomolgi, Plasmodium brasilianum, Plasmodium eylesi, Plasmodium knowlesi, Plasmodium inui, Plasmodium schwetzi and Plasmodium simium. With the exception of P. knowlesi, none of the other species has been found to infect humans in nature. In this report, it is described the first known case of a naturally acquired P. cynomolgi malaria in humans.The patient was a 39-year-old woman from a malaria-free area with no previous history of malaria or travel to endemic areas. Initially, malaria was diagnosed and identified as Plasmodium malariae/P. knowlesi by microscopy in the Terengganu State Health Department. Thick and thin blood films stained with 10% Giemsa were performed for microscopy examination. Molecular species identification was performed at the Institute for Medical Research (IMR, Malaysia) and in the Malaria & Emerging Parasitic Diseases Laboratory (MAPELAB, Spain) using different nested PCR methods.Microscopic re-examination in the IMR showed characteristics of Plasmodium vivax and was confirmed by a nested PCR assay developed by Snounou et al. Instead, a different PCR assay plus sequencing performed at the MAPELAB confirmed that the patient was infected with P. cynomolgi and not with P. vivax.This is the first report of human P. cynomolgi infection acquired in a natural way, but there might be more undiagnosed or misdiagnosed cases, since P. cynomolgi is morphologically indistinguishable from P. vivax, and one of the most used PCR methods for malaria infection detection may identify a P. cynomolgi infection as P. vivax.Simian Plasmodium species may routinely infect humans in Southeast Asia. New diagnostic methods are necessary to distinguish between the human and monkey malaria species. Further epidemiological studies, incriminating also the mosquito vector(s), must be performed to know the relevance of cynomolgi malaria and its

Merozoite surface proteins in red blood cell invasion, immunity and vaccines against malaria

PubMed Central

Beeson, James G.; Drew, Damien R.; Boyle, Michelle J.; Feng, Gaoqian; Fowkes, Freya J.I.; Richards, Jack S.

2016-01-01

Malaria accounts for an enormous burden of disease globally, with Plasmodium falciparum accounting for the majority of malaria, and P. vivax being a second important cause, especially in Asia, the Americas and the Pacific. During infection with Plasmodium spp., the merozoite form of the parasite invades red blood cells and replicates inside them. It is during the blood-stage of infection that malaria disease occurs and, therefore, understanding merozoite invasion, host immune responses to merozoite surface antigens, and targeting merozoite surface proteins and invasion ligands by novel vaccines and therapeutics have been important areas of research. Merozoite invasion involves multiple interactions and events, and substantial processing of merozoite surface proteins occurs before, during and after invasion. The merozoite surface is highly complex, presenting a multitude of antigens to the immune system. This complexity has proved challenging to our efforts to understand merozoite invasion and malaria immunity, and to developing merozoite antigens as malaria vaccines. In recent years, there has been major progress in this field, and several merozoite surface proteins show strong potential as malaria vaccines. Our current knowledge on this topic is reviewed, highlighting recent advances and research priorities. PMID:26833236

Merozoite surface proteins in red blood cell invasion, immunity and vaccines against malaria.

PubMed

Beeson, James G; Drew, Damien R; Boyle, Michelle J; Feng, Gaoqian; Fowkes, Freya J I; Richards, Jack S

2016-05-01

Malaria accounts for an enormous burden of disease globally, with Plasmodium falciparum accounting for the majority of malaria, and P. vivax being a second important cause, especially in Asia, the Americas and the Pacific. During infection with Plasmodium spp., the merozoite form of the parasite invades red blood cells and replicates inside them. It is during the blood-stage of infection that malaria disease occurs and, therefore, understanding merozoite invasion, host immune responses to merozoite surface antigens, and targeting merozoite surface proteins and invasion ligands by novel vaccines and therapeutics have been important areas of research. Merozoite invasion involves multiple interactions and events, and substantial processing of merozoite surface proteins occurs before, during and after invasion. The merozoite surface is highly complex, presenting a multitude of antigens to the immune system. This complexity has proved challenging to our efforts to understand merozoite invasion and malaria immunity, and to developing merozoite antigens as malaria vaccines. In recent years, there has been major progress in this field, and several merozoite surface proteins show strong potential as malaria vaccines. Our current knowledge on this topic is reviewed, highlighting recent advances and research priorities. © FEMS 2016.

Simplified Pan-species Real-time PCR-based Detection of Plasmodium Spp. in Blood Smear.

PubMed

Hassanpour, Gholamreza; Mirhendi, Hossein; Mohebali, Mehdi; Raeisi, Ahmad; Zeraati, Hojjat; Keshavarz, Hossein

2016-01-01

We aimed to quicken and simplify the detection of Plasmodium in blood samples by developing and testing a pan- Plasmodium real-time PCR for accurate screening of individuals suspected of malaria. A single primer/probe set for pan-species Plasmodium -specific real time PCR targeting a conserved region of the small subunit 18S ribosomal DNA was designed and evaluated for rapid diagnosis and screening of malaria infections using dried blood smears. FTA cards were used for rapid and simple DNA extraction. The primers and probes showed a positive response with the DNA extracted from bloods infected with P. falciparum and P. vivax but not with DNA extracted from various smears from uninfected blood samples. Seven positive cases positive by both microscopy and nested PCR were found among 280 blood samples taken from in South and Southeast Iran. Five samples were identified as positive for P. vivax and two as positive for P. falciparum . All positive samples were positive by real-time PCR. Furthermore, all 38-blood samples positive by microscopy were positive by real-time PCR. No microscopy-negative samples were positive by real-time PCR. By using a simple FTA card for DNA extraction and by application of the real-time PCR developed in this study, sensitivity similar to nested-PCR and microscopy was achieved. This format simplifies the detection of Plasmodium in large numbers of samples.

Hematozoa in two populations of the threatened red-billed chough in Spain.

PubMed

Blanco, G; Merino, S; Tella, J L; Fargallo, J A; Gajón, A

1997-07-01

The prevalence of hematozoa in two populations of red-billed choughs (Pyrrhocorax pyrrhocorax) was sampled in 1992 and 1994 in Spain. Two blood parasites infected red-billed choughs. A species of Plasmodium, possibly Plasmodium relictum, and the piroplasm Babesia frugilegica, are described for the first time from this host. Low prevalence (1/178, < 1%) of hematozoa in these populations, was evidence for a lack of effects of blood parasites on the life history and conservation of this threatened species in at least the two populations studied.

TLR4 and TLR9 signals stimulate protective immunity against blood-stage Plasmodium yoelii infection in mice.

PubMed

Zhang, Yanjun; Zhu, Xiaotong; Feng, Yonghui; Pang, Wei; Qi, Zanmei; Cui, Liwang; Cao, Yaming

2016-11-01

The mechanisms regulating the induction of protective immunity against blood-stage malaria remain unclear. Resistant DBA/2 mouse develops a higher Th1 response compared with a susceptible BALB/c strain during Plasmodium yoelii (Py) infection. It is known that the T helper cell response is initiated and polarized by dendritic cells (DCs) of the innate immune system, during which TLR4 and TLR9 are important receptors for the innate recognition of the malaria parasite and its products. We hypothesized that TLR4/9 may play critical roles in the induction of protective immunity against Py infection. We used TLR4/9 antagonists and agonists to study their effects on mouse resistance to Py infection. We found that the administration of an antagonist prior to infection aggravated disease outcomes, impaired DC functions and suppressed the pro-inflammatory response to Py infection in resistant DBA/2 mice. Treatment with the TLR4 agonist lipopolysaccharide (LPS) but not TLR9 agonist significantly improved the survival rate of susceptible Py-infected BALB/c mice. LPS administration promoted the activation and expansion of DCs and drove a Th1-biased response. Our data demonstrate the important roles of TLR4/9 signals in inducing resistance to malaria parasites and provide evidence for the rational use of TLR agonists to potentiate protective immunity against Plasmodium infection. Copyright © 2016 Elsevier Inc. All rights reserved.

Plasmodium ovale infection in Malaysia: first imported case

PubMed Central

2010-01-01

Background Plasmodium ovale infection is rarely reported in Malaysia. This is the first imported case of P. ovale infection in Malaysia which was initially misdiagnosed as Plasmodium vivax. Methods Peripheral blood sample was first examined by Giemsa-stained microscopy examination and further confirmed using a patented in-house multiplex PCR followed by sequencing. Results and Discussion Initial results from peripheral blood smear examination diagnosed P. vivax infection. However further analysis using a patented in-house multiplex PCR followed by sequencing confirmed the presence of P. ovale. Given that Anopheles maculatus and Anopheles dirus, vectors of P. ovale are found in Malaysia, this finding has significant implication on Malaysia's public health sector. Conclusions The current finding should serve as an alert to epidemiologists, clinicians and laboratory technicians in the possibility of finding P. ovale in Malaysia. P. ovale should be considered in the differential diagnosis of imported malaria cases in Malaysia due to the exponential increase in the number of visitors from P. ovale endemic regions and the long latent period of P. ovale. It is also timely that conventional diagnosis of malaria via microscopy should be coupled with more advanced molecular tools for effective diagnosis. PMID:20929588

Plasmodium ovale infection in Malaysia: first imported case.

PubMed

Lim, Yvonne A L; Mahmud, Rohela; Chew, Ching Hoong; T, Thiruventhiran; Chua, Kek Heng

2010-10-08

Plasmodium ovale infection is rarely reported in Malaysia. This is the first imported case of P. ovale infection in Malaysia which was initially misdiagnosed as Plasmodium vivax. Peripheral blood sample was first examined by Giemsa-stained microscopy examination and further confirmed using a patented in-house multiplex PCR followed by sequencing. Initial results from peripheral blood smear examination diagnosed P. vivax infection. However further analysis using a patented in-house multiplex PCR followed by sequencing confirmed the presence of P. ovale. Given that Anopheles maculatus and Anopheles dirus, vectors of P. ovale are found in Malaysia, this finding has significant implication on Malaysia's public health sector. The current finding should serve as an alert to epidemiologists, clinicians and laboratory technicians in the possibility of finding P. ovale in Malaysia. P. ovale should be considered in the differential diagnosis of imported malaria cases in Malaysia due to the exponential increase in the number of visitors from P. ovale endemic regions and the long latent period of P. ovale. It is also timely that conventional diagnosis of malaria via microscopy should be coupled with more advanced molecular tools for effective diagnosis.

Further evaluation of the NWF filter for the purification of Plasmodium vivax-infected erythrocytes.

PubMed

Li, Jiangyan; Tao, Zhiyong; Li, Qian; Brashear, Awtum; Wang, Ying; Xia, Hui; Fang, Qiang; Cui, Liwang

2017-05-17

Isolation of Plasmodium-infected red blood cells (iRBCs) from clinical blood samples is often required for experiments, such as ex vivo drug assays, in vitro invasion assays and genome sequencing. Current methods for removing white blood cells (WBCs) from malaria-infected blood are time-consuming or costly. A prototype non-woven fabric (NWF) filter was developed for the purification of iRBCs, which showed great efficiency for removing WBCs in a pilot study. Previous work was performed with prototype filters optimized for processing 5-10 mL of blood. With the commercialization of the filters, this study aims to evaluate the efficiency and suitability of the commercial NWF filter for the purification of Plasmodium vivax-infected RBCs in smaller volumes of blood and to compare its performance with that of Plasmodipur ® filters. Forty-three clinical P. vivax blood samples taken from symptomatic patients attending malaria clinics at the China-Myanmar border were processed using the NWF filters in a nearby field laboratory. The numbers of WBCs and iRBCs and morphology of P. vivax parasites in the blood samples before and after NWF filtration were compared. The viability of P. vivax parasites after filtration from 27 blood samples was examined by in vitro short-term culture. In addition, the effectiveness of the NWF filter for removing WBCs was compared with that of the Plasmodipur ® filter in six P. vivax blood samples. Filtration of 1-2 mL of P. vivax-infected blood with the NWF filter removed 99.68% WBCs. The densities of total iRBCs, ring and trophozoite stages before and after filtration were not significantly different (P > 0.05). However, the recovery rates of schizont- and gametocyte-infected RBCs, which were minor parasite stages in the clinical samples, were relatively low. After filtration, the P. vivax parasites did not show apparent morphological changes. Culture of 27 P. vivax-infected blood samples after filtration showed that parasites successfully

Simplified Pan-species Real-time PCR-based Detection of Plasmodium Spp. in Blood Smear

PubMed Central

HASSANPOUR, Gholamreza; MIRHENDI, Hossein; MOHEBALI, Mehdi; RAEISI, Ahmad; ZERAATI, Hojjat; KESHAVARZ, Hossein

2016-01-01

Background: We aimed to quicken and simplify the detection of Plasmodium in blood samples by developing and testing a pan-Plasmodium real-time PCR for accurate screening of individuals suspected of malaria. Methods: A single primer/probe set for pan-species Plasmodium-specific real time PCR targeting a conserved region of the small subunit 18S ribosomal DNA was designed and evaluated for rapid diagnosis and screening of malaria infections using dried blood smears. FTA cards were used for rapid and simple DNA extraction. Results: The primers and probes showed a positive response with the DNA extracted from bloods infected with P. falciparum and P. vivax but not with DNA extracted from various smears from uninfected blood samples. Seven positive cases positive by both microscopy and nested PCR were found among 280 blood samples taken from in South and Southeast Iran. Five samples were identified as positive for P. vivax and two as positive for P. falciparum. All positive samples were positive by real-time PCR. Furthermore, all 38-blood samples positive by microscopy were positive by real-time PCR. No microscopy-negative samples were positive by real-time PCR. Conclusion: By using a simple FTA card for DNA extraction and by application of the real-time PCR developed in this study, sensitivity similar to nested-PCR and microscopy was achieved. This format simplifies the detection of Plasmodium in large numbers of samples. PMID:28127357

Flow cytometry as a tool for analyzing changes in Plasmodium falciparum cell cycle following treatment with indol compounds.

PubMed

Schuck, Desirée Cigaran; Ribeiro, Ramira Yuri; Nery, Arthur A; Ulrich, Henning; Garcia, Célia R S

2011-11-01

Melatonin and its derivatives modulate the Plasmodium falciparum and Plasmodium chabaudi cell cycle. Flow cytometry was employed together with the nucleic acid dye YOYO-1 allowing precise discrimination between mono- and multinucleated forms of P. falciparum-infected red blood cell. The use of YOYO-1 permitted excellent discrimination between uninfected and infected red blood cells as well as between early and late parasite stages. Fluorescence intensities of schizont-stage parasites were about 10-fold greater than those of ring-trophozoite form parasites. Melatonin and related indolic compounds including serotonin, N-acetyl-serotonin and tryptamine induced an increase in the percentage of multinucleated forms compared to non-treated control cultures. YOYO-1 staining of infected erythrocyte and subsequent flow cytometry analysis provides a powerful tool in malaria research for screening of bioactive compounds. Copyright © 2011 International Society for Advancement of Cytometry.

Infection and Co-infection with Helminths and Plasmodium among School Children in Côte d’Ivoire: Results from a National Cross-Sectional Survey

PubMed Central

Yapi, Richard B.; Hürlimann, Eveline; Houngbedji, Clarisse A.; Ndri, Prisca B.; Silué, Kigbafori D.; Soro, Gotianwa; Kouamé, Ferdinand N.; Vounatsou, Penelope; Fürst, Thomas; N’Goran, Eliézer K.; Utzinger, Jürg; Raso, Giovanna

2014-01-01

Background Helminth infection and malaria remain major causes of ill-health in the tropics and subtropics. There are several shared risk factors (e.g., poverty), and hence, helminth infection and malaria overlap geographically and temporally. However, the extent and consequences of helminth-Plasmodium co-infection at different spatial scales are poorly understood. Methodology This study was conducted in 92 schools across Côte d’Ivoire during the dry season, from November 2011 to February 2012. School children provided blood samples for detection of Plasmodium infection, stool samples for diagnosis of soil-transmitted helminth (STH) and Schistosoma mansoni infections, and urine samples for appraisal of Schistosoma haematobium infection. A questionnaire was administered to obtain demographic, socioeconomic, and behavioral data. Multinomial regression models were utilized to determine risk factors for STH-Plasmodium and Schistosoma-Plasmodium co-infection. Principal Findings Complete parasitological and questionnaire data were available for 5,104 children aged 5-16 years. 26.2% of the children were infected with any helminth species, whilst the prevalence of Plasmodium infection was 63.3%. STH-Plasmodium co-infection was detected in 13.5% and Schistosoma-Plasmodium in 5.6% of the children. Multinomial regression analysis revealed that boys, children aged 10 years and above, and activities involving close contact to water were significantly and positively associated with STH-Plasmodium co-infection. Boys, wells as source of drinking water, and water contact were significantly and positively associated with Schistosoma-Plasmodium co-infection. Access to latrines, deworming, higher socioeconomic status, and living in urban settings were negatively associated with STH-Plasmodium co-infection; whilst use of deworming drugs and access to modern latrines were negatively associated with Schistosoma-Plasmodium co-infection. Conclusions/Significance More than 60% of the

Reduced erythrocyte susceptibility and increased host clearance of young parasites slows Plasmodium growth in a murine model of severe malaria

NASA Astrophysics Data System (ADS)

Khoury, David S.; Cromer, Deborah; Best, Shannon E.; James, Kylie R.; Sebina, Ismail; Haque, Ashraful; Davenport, Miles P.

2015-05-01

The best correlate of malaria severity in human Plasmodium falciparum (Pf) infection is the total parasite load. Pf-infected humans could control parasite loads by two mechanisms, either decreasing parasite multiplication, or increasing parasite clearance. However, few studies have directly measured these two mechanisms in vivo. Here, we have directly quantified host clearance of parasites during Plasmodium infection in mice. We transferred labelled red blood cells (RBCs) from Plasmodium infected donors into uninfected and infected recipients, and tracked the fate of donor parasites by frequent blood sampling. We then applied age-based mathematical models to characterise parasite clearance in the recipient mice. Our analyses revealed an increased clearance of parasites in infected animals, particularly parasites of a younger developmental stage. However, the major decrease in parasite multiplication in infected mice was not mediated by increased clearance alone, but was accompanied by a significant reduction in the susceptibility of RBCs to parasitisation.

IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

PubMed Central

Sebina, Ismail; James, Kylie R.; Soon, Megan S. F.; Best, Shannon E.; Montes de Oca, Marcela; Amante, Fiona H.; Thomas, Bryce S.; Beattie, Lynette; Souza-Fonseca-Guimaraes, Fernando; Smyth, Mark J.; Hertzog, Paul J.; Hill, Geoffrey R.; Engwerda, Christian R.

2016-01-01

Parasite-specific antibodies protect against blood-stage Plasmodium infection. However, in malaria-endemic regions, it takes many months for naturally-exposed individuals to develop robust humoral immunity. Explanations for this have focused on antigenic variation by Plasmodium, but have considered less whether host production of parasite-specific antibody is sub-optimal. In particular, it is unclear whether host immune factors might limit antibody responses. Here, we explored the effect of Type I Interferon signalling via IFNAR1 on CD4+ T-cell and B-cell responses in two non-lethal murine models of malaria, P. chabaudi chabaudi AS (PcAS) and P. yoelii 17XNL (Py17XNL) infection. Firstly, we demonstrated that CD4+ T-cells and ICOS-signalling were crucial for generating germinal centre (GC) B-cells, plasmablasts and parasite-specific antibodies, and likewise that T follicular helper (Tfh) cell responses relied on B cells. Next, we found that IFNAR1-signalling impeded the resolution of non-lethal blood-stage infection, which was associated with impaired production of parasite-specific IgM and several IgG sub-classes. Consistent with this, GC B-cell formation, Ig-class switching, plasmablast and Tfh differentiation were all impaired by IFNAR1-signalling. IFNAR1-signalling proceeded via conventional dendritic cells, and acted early by limiting activation, proliferation and ICOS expression by CD4+ T-cells, by restricting the localization of activated CD4+ T-cells adjacent to and within B-cell areas of the spleen, and by simultaneously suppressing Th1 and Tfh responses. Finally, IFNAR1-deficiency accelerated humoral immune responses and parasite control by boosting ICOS-signalling. Thus, we provide evidence of a host innate cytokine response that impedes the onset of humoral immunity during experimental malaria. PMID:27812214

Plasmodium falciparum full life cycle and Plasmodium ovale liver stages in humanized mice.

PubMed

Soulard, Valérie; Bosson-Vanga, Henriette; Lorthiois, Audrey; Roucher, Clémentine; Franetich, Jean-François; Zanghi, Gigliola; Bordessoulles, Mallaury; Tefit, Maurel; Thellier, Marc; Morosan, Serban; Le Naour, Gilles; Capron, Frédérique; Suemizu, Hiroshi; Snounou, Georges; Moreno-Sabater, Alicia; Mazier, Dominique

2015-07-24

Experimental studies of Plasmodium parasites that infect humans are restricted by their host specificity. Humanized mice offer a means to overcome this and further provide the opportunity to observe the parasites in vivo. Here we improve on previous protocols to achieve efficient double engraftment of TK-NOG mice by human primary hepatocytes and red blood cells. Thus, we obtain the complete hepatic development of P. falciparum, the transition to the erythrocytic stages, their subsequent multiplication, and the appearance of mature gametocytes over an extended period of observation. Furthermore, using sporozoites derived from two P. ovale-infected patients, we show that human hepatocytes engrafted in TK-NOG mice sustain maturation of the liver stages, and the presence of late-developing schizonts indicate the eventual activation of quiescent parasites. Thus, TK-NOG mice are highly suited for in vivo observations on the Plasmodium species of humans.

Infectivity of Plasmodium falciparum sporozoites determines emerging parasitemia in infected volunteers.

PubMed

McCall, Matthew B B; Wammes, Linda J; Langenberg, Marijke C C; van Gemert, Geert-Jan; Walk, Jona; Hermsen, Cornelus C; Graumans, Wouter; Koelewijn, Rob; Franetich, Jean-François; Chishimba, Sandra; Gerdsen, Max; Lorthiois, Audrey; van de Vegte, Marga; Mazier, Dominique; Bijker, Else M; van Hellemond, Jaap J; van Genderen, Perry J J; Sauerwein, Robert W

2017-06-21

Malaria sporozoites must first undergo intrahepatic development before a pathogenic blood-stage infection is established. The success of infection depends on host and parasite factors. In healthy human volunteers undergoing controlled human malaria infection (CHMI), we directly compared three clinical Plasmodium falciparum isolates for their ability to infect primary human hepatocytes in vitro and to drive the production of blood-stage parasites in vivo. Our data show a correlation between the efficiency of strain-specific sporozoite invasion of human hepatocytes and the dynamics of patent parasitemia in study subjects, highlighting intrinsic differences in infectivity among P. falciparum isolates from distinct geographical locales. The observed heterogeneity in infectivity among strains underscores the value of assessing the protective efficacy of candidate malaria vaccines against heterologous strains in the CHMI model. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Long-term pathogenic response to Plasmodium relictum infection in Culex pipiens mosquito.

PubMed

Pigeault, Romain; Villa, Manon

2018-01-01

The transmission of Plasmodium within a vertebrate host population is strongly associated with the life history traits of its vector. Therefore the effect of malaria infection on mosquito fecundity and longevity has traditionally received a lot of attention. Several species of malaria parasites reduce mosquito fecundity, nevertheless almost all of the studies have focused only on the first gonotrophic cycle. Yet, during their lifetime, female mosquitoes go through several gonotrophic cycles, which raises the question of whether they are able to compensate the fecundity costs induced by the parasite. The impact of Plasmodium infection on female longevity is not so clear and has produced conflicting results. Here we measured the impact of Plasmodium relictum on its vector's longevity and fecundity during three consecutive gonotrophic cycles. In accordance with previous studies, we observed a negative impact of Plasmodium infection on mosquito (Culex pipiens) fecundity in the first gonotrophic cycle. Interestingly, despite having taken two subsequent uninfected blood meals, the negative impact of malaria parasite persisted. Nevertheless no impact of infection on mosquito longevity was observed. Our results are not in line with the hypothesis that the reduction of fecundity observed in infected mosquitoes is an adaptive strategy of Plasmodium to increase the longevity of its vector. We discuss the different underlying mechanisms that may explain our results.

Helminth Parasites Alter Protection against Plasmodium Infection

PubMed Central

Salazar-Castañon, Víctor H.; Legorreta-Herrera, Martha

2014-01-01

More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response. PMID:25276830

Helminth parasites alter protection against Plasmodium infection.

PubMed

Salazar-Castañon, Víctor H; Legorreta-Herrera, Martha; Rodriguez-Sosa, Miriam

2014-01-01

More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response.

First case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia.

PubMed

Tanizaki, Ryutaro; Ujiie, Mugen; Kato, Yasuyuki; Iwagami, Moritoshi; Hashimoto, Aki; Kutsuna, Satoshi; Takeshita, Nozomi; Hayakawa, Kyoko; Kanagawa, Shuzo; Kano, Shigeyuki; Ohmagari, Norio

2013-04-15

This is the first case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia. In September 2012, a previously healthy 35-year-old Japanese man presented to National Center for Global Health and Medicine in Tokyo with a two-day history of daily fever, mild headaches and mild arthralgia. Malaria parasites were found in the Giemsa-stained thin blood smear, which showed band forms similar to Plasmodium malariae. Although a nested PCR showed the amplification of the primer of Plasmodium vivax and Plasmodium knowlesi, he was finally diagnosed with P. knowlesi mono-infection by DNA sequencing. He was treated with mefloquine, and recovered without any complications. DNA sequencing of the PCR products is indispensable to confirm P. knowlesi infection, however there is limited access to DNA sequencing procedures in endemic areas. The extent of P. knowlesi transmission in Asia has not been clearly defined. There is limited availability of diagnostic tests and routine surveillance system for reporting an accurate diagnosis in the Asian endemic regions. Thus, reporting accurately diagnosed cases of P. knowlesi infection in travellers would be important for assessing the true nature of this emerging human infection.

Bone Marrow Is a Major Parasite Reservoir in Plasmodium vivax Infection

PubMed Central

2018-01-01

ABSTRACT Plasmodium vivax causes heavy burdens of disease across malarious regions worldwide. Mature P. vivax asexual and transmissive gametocyte stages occur in the blood circulation, and it is often assumed that accumulation/sequestration in tissues is not an important phase in their development. Here, we present a systematic study of P. vivax stage distributions in infected tissues of nonhuman primate (NHP) malaria models as well as in blood from human infections. In a comparative analysis of the transcriptomes of P. vivax and Plasmodium falciparum blood-stage parasites, we found a conserved cascade of stage-specific gene expression despite the greatly different gametocyte maturity times of these two species. Using this knowledge, we validated a set of conserved asexual- and gametocyte-stage markers both by quantitative real-time PCR and by antibody assays of peripheral blood samples from infected patients and NHP (Aotus sp.). Histological analyses of P. vivax parasites in organs of 13 infected NHP (Aotus and Saimiri species) demonstrated a major fraction of immature gametocytes in the parenchyma of the bone marrow, while asexual schizont forms were enriched to a somewhat lesser extent in this region of the bone marrow as well as in sinusoids of the liver. These findings suggest that the bone marrow is an important reservoir for gametocyte development and proliferation of malaria parasites. PMID:29739900

Plasmodium malariae and Plasmodium ovale infections in the China-Myanmar border area.

PubMed

Li, Peipei; Zhao, Zhenjun; Xing, Hua; Li, Wenli; Zhu, Xiaotong; Cao, Yaming; Yang, Zhaoqing; Sattabongkot, Jetsumon; Yan, Guiyun; Fan, Qi; Cui, Liwang

2016-11-15

The Greater Mekong Subregion is aiming to achieve regional malaria elimination by 2030. Though a shift in malaria parasite species predominance by Plasmodium vivax has been recently documented, the transmission of the two minor Plasmodium species, Plasmodium malariae and Plasmodium ovale spp., is poorly characterized in the region. This study aims to determine the prevalence of these minor species in the China-Myanmar border area and their genetic diversity. Epidemiology study was conducted during passive case detection in hospitals and clinics in Myanmar and four counties in China along the China-Myanmar border. Cross-sectional surveys were conducted in villages and camps for internally displaced persons to determine the prevalence of malaria infections. Malaria infections were diagnosed initially by microscopy and later in the laboratory using nested PCR for the SSU rRNA genes. Plasmodium malariae and P. ovale infections were confirmed by sequencing the PCR products. The P. ovale subtypes were determined by sequencing the Pocytb, Pocox1 and Pog3p genes. Parasite populations were evaluated by PCR amplification and sequencing of the MSP-1 genes. Antifolate sensitivity was assessed by sequencing the dhfr-ts and dhps genes from the P. malariae and P. ovale isolates. Analysis of 2701 blood samples collected from the China-Myanmar border by nested PCR targeting the parasite SSU rRNA genes identified 561 malaria cases, including 161 Plasmodium falciparum, 327 P. vivax, 66 P. falciparum/P. vivax mixed infections, 4 P. malariae and 3 P. ovale spp. P. vivax and P. falciparum accounted for >60 and ~30% of all malaria cases, respectively. In comparison, the prevalence of P. malariae and P. ovale spp. was very low and only made up ~1% of all PCR-positive cases. Nevertheless, these two species were often misidentified as P. vivax infections or completely missed by microscopy even among symptomatic patients. Phylogenetic analysis of the SSU rRNA, Pocytb, Pocox1 and Pog3p genes

[Iditification of five imported cases of Plasmodium ovale wallikeri infection in Zhejiang Province].

PubMed

Zhang, Ling-ling; Ruan, Wei; Chen, Hua-liang; Lu, Qiao-yi; Yao, Li-nong

2014-10-01

To identify and analyze Plasmodium ovale wallikeri in 5 imported malaria cases, who were detected positive by microscopy and negative by conventional PCR. Epidemiological information and blood samples were collected from the five patients. The detection was conducted by microscopy, Rapid Diagnostic Test (RDT) and nested PCR with Plasmodium genus-specific, species-specific and Plasmodium ovale wallikeri-specific primers. The amplified products were sequenced and Blast analysis was performed on line in NCBI. The five patients returned from Africa, and all had a history of malaria. They were microscopically positive for Plasmodium sp., and two cases showed Pan positive RDT result. All blood samples were negative for four Plasmodium spp. by conventional nested PCR, but positive by nested PCR with Plasmodium ovale wallikeri-specific primers. Blast analysis showed that the amplified sequences of the five cases had complete homology with P. ovale wallikeri clone RSH10 18S ribosomal RNA gene (Accession No. KF219561.1). The five cases which classified as positive by microscopy while negative by conventional PCR have been confirmed as Plasmodium ovale wallikeri infection by nested PCR with P. ovale wallikeri-specific primers.

Composition of Anopheles mosquitoes, their blood-meal hosts, and Plasmodium falciparum infection rates in three islands with disparate bed net coverage in Lake Victoria, Kenya.

PubMed

Ogola, Edwin; Villinger, Jandouwe; Mabuka, Danspaid; Omondi, David; Orindi, Benedict; Mutunga, James; Owino, Vincent; Masiga, Daniel K

2017-09-08

Small islands serve as potential malaria reservoirs through which new infections might come to the mainland and may be important targets in malaria elimination efforts. This study investigated malaria vector species diversity, blood-meal hosts, Plasmodium infection rates, and long-lasting insecticidal net (LLIN) coverage on Mageta, Magare and Ngodhe Islands of Lake Victoria in western Kenya, a region where extensive vector control is implemented on the mainland. From trapping for six consecutive nights per month (November 2012 to March 2015) using CDC light traps, pyrethrum spray catches and backpack aspiration, 1868 Anopheles mosquitoes were collected. Based on their cytochrome oxidase I (COI) and intergenic spacer region PCR and sequencing, Anopheles gambiae s.l. (68.52%), Anopheles coustani (19.81%) and Anopheles funestus s.l. (11.67%) mosquitoes were differentiated. The mean abundance of Anopheles mosquitoes per building per trap was significantly higher (p < 0.001) in Mageta than in Magare and Ngodhe. Mageta was also the most populated island (n = 6487) with low LLIN coverage of 62.35% compared to Ngodhe (n = 484; 88.31%) and Magare (n = 250; 98.59%). Overall, 416 (22.27%) engorged Anopheles mosquitoes were analysed, of which 41 tested positive for Plasmodium falciparum infection by high-resolution melting (HRM) analysis of 18S rRNA and cytochrome b PCR products. Plasmodium falciparum infection rates were 10.00, 11.76, 0, and 18.75% among blood-fed An. gambiae s.s. (n = 320), Anopheles arabiensis (n = 51), An. funestus s.s. (n = 29), and An. coustani (n = 16), respectively. Based on HRM analysis of vertebrate cytochrome b, 16S rRNA and COI PCR products, humans (72.36%) were the prominent blood-meal hosts of malaria vectors, but 20.91% of blood-meals were from non-human vertebrate hosts. These findings demonstrate high Plasmodium infection rates among the primary malaria vectors An. gambiae s.s. and An. arabiensis, as well as in An. coustani

Survival of Plasmodium falciparum in human blood during refrigeration.

PubMed

Chattopadhyay, Rana; Majam, Victoria F; Kumar, Sanjai

2011-03-01

Transfusion-transmitted malaria remains a serious concern for blood safety. Viable Plasmodium parasites must be present in human blood to transmit malaria, but their survival in blood over time stored under refrigeration has never been carefully investigated. We spiked leukoreduced normal human blood with Plasmodium falciparum (3D7 strain) asexual ring-stage parasites and stored it at 4 °C for 28 days, taking samples at different days intervals. We evaluated the samples for parasitemia by blood film microscopy and by culturing red blood cells (RBCs) to allow further development of parasites. We observed a significant reduction in parasitemia (0.5% vs. 0.12%) after only 1 day in storage at 4 °C. Thereafter, reduction in parasitemia was relatively gradual. Microscopically detectable parasites were present even after 28 days of storage. However, after storing for more than 14 days at 4 °C, parasites no longer replicated when cultured in vitro. Although the storage of asexual blood-stage P. falciparum parasites at 4 °C is detrimental to their survival (a 7.1-fold reduction in parasitemia after 14 days in storage), parasites remained microscopically detectable for 28 days, the end time point of our study. Further in vitro and in vivo studies will be needed to confirm loss of viability of P. falciparum after 14 days in storage, but our initial efforts repeatedly failed to show maturation and development of the parasites in cultured RBCs after that time. © 2010 American Association of Blood Banks.

A novel method for extracting nucleic acids from dried blood spots for ultrasensitive detection of low-density Plasmodium falciparum and Plasmodium vivax infections.

PubMed

Zainabadi, Kayvan; Adams, Matthew; Han, Zay Yar; Lwin, Hnin Wai; Han, Kay Thwe; Ouattara, Amed; Thura, Si; Plowe, Christopher V; Nyunt, Myaing M

2017-09-18

Greater Mekong Subregion countries are committed to eliminating Plasmodium falciparum malaria by 2025. Current elimination interventions target infections at parasite densities that can be detected by standard microscopy or rapid diagnostic tests (RDTs). More sensitive detection methods have been developed to detect lower density "asymptomatic" infections that may represent an important transmission reservoir. These ultrasensitive polymerase chain reaction (usPCR) tests have been used to identify target populations for mass drug administration (MDA). To date, malaria usPCR tests have used either venous or capillary blood sampling, which entails complex sample collection, processing and shipping requirements. An ultrasensitive method performed on standard dried blood spots (DBS) would greatly facilitate the molecular surveillance studies needed for targeting elimination interventions. A highly sensitive method for detecting Plasmodium falciparum and P. vivax 18S ribosomal RNA from DBS was developed by empirically optimizing nucleic acid extraction conditions. The limit of detection (LoD) was determined using spiked DBS samples that were dried and stored under simulated field conditions. Further, to assess its utility for routine molecular surveillance, two cross-sectional surveys were performed in Myanmar during the wet and dry seasons. The lower LoD of the DBS-based ultrasensitive assay was 20 parasites/mL for DBS collected on Whatman 3MM filter paper and 23 parasites/mL for Whatman 903 Protein Saver cards-equivalent to 1 parasite per 50 µL DBS. This is about 5000-fold more sensitive than standard RDTs and similar to the LoD of ≤16-22 parasites/mL reported for other ultrasensitive methods based on whole blood. In two cross-sectional surveys in Myanmar, nearly identical prevalence estimates were obtained from contemporaneous DBS samples and capillary blood samples collected during the wet and dry season. The DBS-based ultrasensitive method described in this

Microvascular hemodynamics and in vivo evidence for the role of intercellular adhesion molecule-1 in the sequestration of infected red blood cells in a mouse model of lethal malaria.

PubMed

Kaul, D K; Liu, X D; Nagel, R L; Shear, H L

1998-02-01

The cytoadherence of infected red blood cells (IRBCs) to the vascular endothelium is the major cause of IRBC sequestration and vessel blockage in the cerebral form of human malaria. Among the rodent models of malaria, Plasmodium yoelii 17XL-infected mice show many similarities with the human cerebral malaria caused by P. falciparum. In both, the sequestration of IRBCs in the brain vessels is secondary to the cytoadherence of IRBCs to the vascular endothelium. Similar to P. falciparum infection in the human but in contrast to P. berghei ANKA infection in mice, P. yoelii 17XL results in little, if any, accumulation of monocytes in the brain. In vivo microcirculatory studies reported here were designed to further understand the hemodynamic aspects and mechanisms underlying cytoadherence of IRBCs in the P. yoelii model using the easily accessible cremaster muscle vasculature. The results show significant decreases in arteriovenous red blood cell velocities (Vrbc) and wall shear rates in the microcirculation of P. yoelii-infected mice, with a maximal decrease occurring in small-diameter postcapillary venules, the main sites of cytoadherence. This reflects contributions from IRBC cytoadherence as well as from increased rigidity of parasitized red blood cells. No cytoadherence is observed in arterioles of the infected mice despite decreased wall shear rates, indicating that endothelial receptors for cytoadherence are restricted to venules. Infusion of a monoclonal antibody (MAb) against the intercellular adhesion molecule-1 (ICAM-1) resulted in significant increases in both arteriolar and venular Vrbc and wall shear rates, accompanied by detachment of adhered IRBCs at some venular sites. The peripheral blood smears taken after the MAb infusion showed a distinct increase in the percentage of schizonts, again indicating detachment and/or prevention of cytoadherence. An MAb against the vascular cell adhesion molecule-1 (VCAM-1) as well as an irrelevant control antibody had

Multiplicity and molecular epidemiology of Plasmodium vivax and Plasmodium falciparum infections in East Africa.

PubMed

Zhong, Daibin; Lo, Eugenia; Wang, Xiaoming; Yewhalaw, Delenasaw; Zhou, Guofa; Atieli, Harrysone E; Githeko, Andrew; Hemming-Schroeder, Elizabeth; Lee, Ming-Chieh; Afrane, Yaw; Yan, Guiyun

2018-05-02

Parasite genetic diversity and multiplicity of infection (MOI) affect clinical outcomes, response to drug treatment and naturally-acquired or vaccine-induced immunity. Traditional methods often underestimate the frequency and diversity of multiclonal infections due to technical sensitivity and specificity. Next-generation sequencing techniques provide a novel opportunity to study complexity of parasite populations and molecular epidemiology. Symptomatic and asymptomatic Plasmodium vivax samples were collected from health centres/hospitals and schools, respectively, from 2011 to 2015 in Ethiopia. Similarly, both symptomatic and asymptomatic Plasmodium falciparum samples were collected, respectively, from hospitals and schools in 2005 and 2015 in Kenya. Finger-pricked blood samples were collected and dried on filter paper. Long amplicon (> 400 bp) deep sequencing of merozoite surface protein 1 (msp1) gene was conducted to determine multiplicity and molecular epidemiology of P. vivax and P. falciparum infections. The results were compared with those based on short amplicon (117 bp) deep sequencing. A total of 139 P. vivax and 222 P. falciparum samples were pyro-sequenced for pvmsp1 and pfmsp1, yielding a total of 21 P. vivax and 99 P. falciparum predominant haplotypes. The average MOI for P. vivax and P. falciparum were 2.16 and 2.68, respectively, which were significantly higher than that of microsatellite markers and short amplicon (117 bp) deep sequencing. Multiclonal infections were detected in 62.2% of the samples for P. vivax and 74.8% of the samples for P. falciparum. Four out of the five subjects with recurrent P. vivax malaria were found to be a relapse 44-65 days after clearance of parasites. No difference was observed in MOI among P. vivax patients of different symptoms, ages and genders. Similar patterns were also observed in P. falciparum except for one study site in Kenyan lowland areas with significantly higher MOI. The study used a novel method

Plasmodium Parasitemia Associated With Increased Survival in Ebola Virus–Infected Patients

PubMed Central

Rosenke, Kyle; Adjemian, Jennifer; Munster, Vincent J.; Marzi, Andrea; Falzarano, Darryl; Onyango, Clayton O.; Ochieng, Melvin; Juma, Bonventure; Fischer, Robert J.; Prescott, Joseph B.; Safronetz, David; Omballa, Victor; Owuor, Collins; Hoenen, Thomas; Groseth, Allison; Martellaro, Cynthia; van Doremalen, Neeltje; Zemtsova, Galina; Self, Joshua; Bushmaker, Trenton; McNally, Kristin; Rowe, Thomas; Emery, Shannon L.; Feldmann, Friederike; Williamson, Brandi N.; Best, Sonja M.; Nyenswah, Tolbert G.; Grolla, Allen; Strong, James E.; Kobinger, Gary; Bolay, Fatorma K.; Zoon, Kathryn C.; Stassijns, Jorgen; Giuliani, Ruggero; de Smet, Martin; Nichol, Stuart T.; Fields, Barry; Sprecher, Armand; Massaquoi, Moses; Feldmann, Heinz; de Wit, Emmie

2016-01-01

Background. The ongoing Ebola outbreak in West Africa has resulted in 28 646 suspected, probable, and confirmed Ebola virus infections. Nevertheless, malaria remains a large public health burden in the region affected by the outbreak. A joint Centers for Disease Control and Prevention/National Institutes of Health diagnostic laboratory was established in Monrovia, Liberia, in August 2014, to provide laboratory diagnostics for Ebola virus. Methods. All blood samples from suspected Ebola virus–infected patients admitted to the Médecins Sans Frontières ELWA3 Ebola treatment unit in Monrovia were tested by quantitative real-time polymerase chain reaction for the presence of Ebola virus and Plasmodium species RNA. Clinical outcome in laboratory-confirmed Ebola virus–infected patients was analyzed as a function of age, sex, Ebola viremia, and Plasmodium species parasitemia. Results. The case fatality rate of 1182 patients with laboratory-confirmed Ebola virus infections was 52%. The probability of surviving decreased with increasing age and decreased with increasing Ebola viral load. Ebola virus–infected patients were 20% more likely to survive when Plasmodium species parasitemia was detected, even after controlling for Ebola viral load and age; those with the highest levels of parasitemia had a survival rate of 83%. This effect was independent of treatment with antimalarials, as this was provided to all patients. Moreover, treatment with antimalarials did not affect survival in the Ebola virus mouse model. Conclusions. Plasmodium species parasitemia is associated with an increase in the probability of surviving Ebola virus infection. More research is needed to understand the molecular mechanism underlying this remarkable phenomenon and translate it into treatment options for Ebola virus infection. PMID:27531847

A Two-Dimensional Numerical Investigation of Transport of Malaria-Infected Red Blood Cells in Stenotic Microchannels

PubMed Central

Tao, Yong; Rongin, Uwitije; Xing, Zhongwen

2016-01-01

The malaria-infected red blood cells experience a significant decrease in cell deformability and increase in cell membrane adhesion. Blood hemodynamics in microvessels is significantly affected by the alteration of the mechanical property as well as the aggregation of parasitized red blood cells. In this study, we aim to numerically study the connection between cell-level mechanobiological properties of human red blood cells and related malaria disease state by investigating the transport of multiple red blood cell aggregates passing through microchannels with symmetric stenosis. Effects of stenosis magnitude, aggregation strength, and cell deformability on cell rheology and flow characteristics were studied by a two-dimensional model using the fictitious domain-immersed boundary method. The results indicated that the motion and dissociation of red blood cell aggregates were influenced by these factors and the flow resistance increases with the increase of aggregating strength and cell stiffness. Further, the roughness of the velocity profile was enhanced by cell aggregation, which considerably affected the blood flow characteristics. The study may assist us in understanding cellular-level mechanisms in disease development. PMID:28105411

Vivax malaria in a blood donor in Spain, relapse or a new infection in a malaria non-endemic country?

PubMed

Rubio, J M; Jiménez Del Bianco, A I; Cervera-Alonso, Y; Fernandez-Garcia, M D; Lanza, M; Ta Tang, T H; Sevil Puras, F; Blanco, L

2016-02-01

Malaria is a vectorborne disease caused by protozoan of the genus Plasmodium, which can also be transmitted by the transfusion of infected red blood cells. One year after return from a travel to Honduras, a Spanish traveller developed vivax malaria. Prior to the onset of symptoms, the donor made a donation that tested non-reactive using an immunological test for malaria. Samples from the donor taken before donation and tested by serological and molecular methods were negative but positive at the time of hospital admission. The possible sources of the donors' infection, imported versus locally acquired, are discussed. © 2015 International Society of Blood Transfusion.

Hemoparasites in a wild primate: Infection patterns suggest interaction of Plasmodium and Babesia in a lemur species☆

PubMed Central

Springer, Andrea; Fichtel, Claudia; Calvignac-Spencer, Sébastien; Leendertz, Fabian H.; Kappeler, Peter M.

2015-01-01

Hemoparasites can cause serious morbidity in humans and animals and often involve wildlife reservoirs. Understanding patterns of hemoparasite infections in natural populations can therefore inform about emerging disease risks, especially in the light of climate change and human disruption of natural ecosystems. We investigated the effects of host age, sex, host group size and season on infection patterns of Plasmodium sp., Babesia sp. and filarial nematodes in a population of wild Malagasy primates, Verreaux's sifakas (Propithecus verreauxi), as well as the effects of these infections on hematological variables. We tested 45 blood samples from 36 individuals and identified two species of Plasmodium, one species of Babesia and two species of filarial nematodes. Plasmodium spp. and Babesia sp. infections showed opposite patterns of age-dependency, with babesiosis being prevalent among young animals, while older animals were infected with Plasmodium sp. In addition, Babesia sp. infection was a statistically significant negative predictor of Plasmodium sp. infection. These results suggest that Plasmodium and Babesia parasites may interact within the host, either through cross-immunity or via resource competition, so that Plasmodium infections can only establish after babesiosis has resolved. We found no effects of host sex, host group size and season on hemoparasite infections. Infections showed high prevalences and did not influence hematological variables. This preliminary evidence supports the impression that the hosts and parasites considered in this study appear to be well-adapted to each other, resulting in persistent infections with low pathogenic and probably low zoonotic potential. Our results illustrate the crucial role of biodiversity in host-parasite relationships, specifically how within-host pathogen diversity may regulate the abundance of parasites. PMID:26767166

Hemoparasites in a wild primate: Infection patterns suggest interaction of Plasmodium and Babesia in a lemur species.

PubMed

Springer, Andrea; Fichtel, Claudia; Calvignac-Spencer, Sébastien; Leendertz, Fabian H; Kappeler, Peter M

2015-12-01

Hemoparasites can cause serious morbidity in humans and animals and often involve wildlife reservoirs. Understanding patterns of hemoparasite infections in natural populations can therefore inform about emerging disease risks, especially in the light of climate change and human disruption of natural ecosystems. We investigated the effects of host age, sex, host group size and season on infection patterns of Plasmodium sp., Babesia sp. and filarial nematodes in a population of wild Malagasy primates, Verreaux's sifakas (Propithecus verreauxi), as well as the effects of these infections on hematological variables. We tested 45 blood samples from 36 individuals and identified two species of Plasmodium, one species of Babesia and two species of filarial nematodes. Plasmodium spp. and Babesia sp. infections showed opposite patterns of age-dependency, with babesiosis being prevalent among young animals, while older animals were infected with Plasmodium sp. In addition, Babesia sp. infection was a statistically significant negative predictor of Plasmodium sp. infection. These results suggest that Plasmodium and Babesia parasites may interact within the host, either through cross-immunity or via resource competition, so that Plasmodium infections can only establish after babesiosis has resolved. We found no effects of host sex, host group size and season on hemoparasite infections. Infections showed high prevalences and did not influence hematological variables. This preliminary evidence supports the impression that the hosts and parasites considered in this study appear to be well-adapted to each other, resulting in persistent infections with low pathogenic and probably low zoonotic potential. Our results illustrate the crucial role of biodiversity in host-parasite relationships, specifically how within-host pathogen diversity may regulate the abundance of parasites.

Cytokine profiles among patients co-infected with Plasmodium falciparum malaria and soil borne helminths attending Kampala International University Teaching Hospital, in Uganda.

PubMed

Bwanika, Richard; Kato, Charles D; Welishe, Johnson; Mwandah, Daniel C

2018-01-01

Malaria and helminths share the same geographical distribution in tropical Africa. Studies of the interaction of helminth and malaria co-infection in humans have been few and are mainly epidemiological, with little information on cellular immune responses. This study aimed to determine Cytokine profiles among patients co-infected with Plasmodium falciparum malaria and soil borne helminth attending Kampala International University Teaching Hospital (KIU). A case control study of 240 patients were recruited at KIU teaching hospital. Patients with Plasmodium falciparum malaria were 55 (22.9%) and those with soil-borne helminths were 63 (26.3%). The controls were 89 (37.1%), while those co-infected with Plasmodium falciparum malaria and soil-borne helminths were 33 (13.8%). Cases were defined as having a positive blood smear for P. falciparum malaria, those with helminths or co-infections of the two. Negative controls were those with a negative blood smear for P. falciparum malaria and those with no stool parasitic infections. Patients presenting with signs and symptoms of malaria or those suspected of having helminths were recruited for the study. A panel of five cytokines (IFN-γ, TNF-α, IL-6, TGF-β and IL-10) were assayed from plasma samples in patients with and without Plasmodium falciparum malaria, patients with and without helminth, and then those co-infected with the two diseases diagnosis was done using thick blood smears stained with 10% Giemsa and stool examination was done following the Kato Katz technique following standard procedures. The prevalence of Plasmodium falciparum malaria by sex was 28 (11.7%) and 27 (11.3%) in male and female respectively. The overall prevalence of soil borne helminth was 26.3%, and among those harbouring helminths, 13.8% were co-infected with Plasmodium falciparum. Cytokine levels significantly differed across Plasmodium falciparum malaria, soil borne helminth infected patients and health controls for IFN-γ (P = 0.023), IL

Detection of mixed infection level of Plasmodium falciparum and Plasmodium vivax by SYBR Green I-based real-time PCR in North Gondar, north-west Ethiopia.

PubMed

Tajebe, Addimas; Magoma, Gabriel; Aemero, Mulugeta; Kimani, Francis

2014-10-18

Malaria is caused by five Plasmodium species and transmitted by anopheline mosquitoes. It occurs in single and mixed infections. Mixed infection easily leads to misdiagnosis. Accurate detection of malaria species is vital. Therefore, the study was conducted to determine the level of mixed infection and misdiagnosis of malaria species in the study area using SYBR Green I-based real time PCR. The study was conducted in seven health centres from North Gondar, north-west Ethiopia. The data of all febrile patients, who attended the outpatient department for malaria diagnosis, from October to December 2013, was recorded. Dried blood spots were prepared from 168 positive samples for molecular re-evaluation. Parasite DNA was extracted using a commercial kit and Plasmodium species were re-evaluated with SYBR Green I-based real time PCR to detect mixed infections and misdiagnosed mono-infections. Among 7343 patients who were diagnosed for malaria in six study sites within the second quarter of the Ethiopian fiscal year (2013) 1802 (24.54%) were positive for malaria parasite. Out of this, 1,216 (67.48%) Plasmodium falciparum, 553 (30.68%) Plasmodium vivax and 33 (1.8%) mixed infections of both species were recorded. The result showed high prevalence of P. falciparum and P. vivax, but very low prevalence of mixed infections. Among 168 samples collected on dried blood spot 7 (4.17%) were P. vivax, 158 (94.05%) were P. falciparum and 3 (1.80%) were mixed infections of both species. After re-evaluation 10 (5.95%) P. vivax, 112 (66.67%) P. falciparum, 21 (12.50%) P. falciparum + P. vivax mixed infection, and 17 (10.12%) Plasmodium ovale positive rate was recorded. The re-evaluation showed high level of mixed infection, and misdiagnosis of P. ovale and P. vivax. The result shows that P. falciparum prevalence is higher than P. vivax in the study area. The results, obtained from SYBR Green I-based real time PCR, indicated that the diagnosis efficiency of microscopy is very low for

Plasmodium infection decreases fecundity and increases survival of mosquitoes.

PubMed

Vézilier, J; Nicot, A; Gandon, S; Rivero, A

2012-10-07

Long-lived mosquitoes maximize the chances of Plasmodium transmission. Yet, in spite of decades of research, the effect of Plasmodium parasites on mosquito longevity remains highly controversial. On the one hand, many studies report shorter lifespans in infected mosquitoes. On the other hand, parallel (but separate) studies show that Plasmodium reduces fecundity and imply that this is an adaptive strategy of the parasite aimed at redirecting resources towards longevity. No study till date has, however, investigated fecundity and longevity in the same individuals to see whether this prediction holds. In this study, we follow for both fecundity and longevity in Plasmodium-infected and uninfected mosquitoes using a novel, albeit natural, experimental system. We also explore whether the genetic variations that arise through the evolution of insecticide resistance modulate the effect of Plasmodium on these two life-history traits. We show that (i) a reduction in fecundity in Plasmodium-infected mosquitoes is accompanied by an increase in longevity; (ii) this increase in longevity arises through a trade-off between reproduction and survival; and (iii) in insecticide-resistant mosquitoes, the slope of this trade-off is steeper when the mosquito is infected by Plasmodium (cost of insecticide resistance).

Molecular Mechanistic Insights into the Endothelial Receptor Mediated Cytoadherence of Plasmodium falciparum-Infected Erythrocytes

PubMed Central

Li, Ang; Lim, Tong Seng; Shi, Hui; Yin, Jing; Tan, Swee Jin; Li, Zhengjun; Low, Boon Chuan; Tan, Kevin Shyong Wei; Lim, Chwee Teck

2011-01-01

Cytoadherence or sequestration is essential for the pathogenesis of the most virulent human malaria species, Plasmodium falciparum (P. falciparum). Similar to leukocyte-endothelium interaction in response to inflammation, cytoadherence of P. falciparum infected red blood cells (IRBCs) to endothelium occurs under physiological shear stresses in blood vessels and involves an array of molecule complexes which cooperate to form stable binding. Here, we applied single-molecule force spectroscopy technique to quantify the dynamic force spectra and characterize the intrinsic kinetic parameters for specific ligand-receptor interactions involving two endothelial receptor proteins: thrombospondin (TSP) and CD36. It was shown that CD36 mediated interaction was much more stable than that mediated by TSP at single molecule level, although TSP-IRBC interaction appeared stronger than CD36-IRBC interaction in the high pulling rate regime. This suggests that TSP-mediated interaction may initiate cell adhesion by capturing the fast flowing IRBCs whereas CD36 functions as the ‘holder’ for providing stable binding. PMID:21437286

Plasmodium vivax trophozoite-stage proteomes

PubMed Central

Anderson, D.C.; Lapp, Stacey A.; Akinyi, Sheila; Meyer, Esmeralda V.S.; Barnwell, John W.; Korir-Morrison, Cindy; Galinski, Mary R.

2015-01-01

Plasmodium vivax is the causative infectious agent of 80–300 million annual cases of malaria. Many aspects of this parasite’s biology remain unknown. To further elucidate the interaction of P. vivax with its Saimiri boliviensis host, we obtained detailed proteomes of infected red blood cells, representing the trophozoite-enriched stage of development. Data from two of three biological replicate proteomes, emphasized here, were analyzed using five search engines, which enhanced identifications and resulted in the most comprehensive P. vivax proteomes to date, with 1375 P. vivax and 3209 S. boliviensis identified proteins. Ribosome subunit proteins were noted for both P. vivax and S. boliviensis, consistent with P. vivax’s known reticulocyte host–cell specificity. A majority of the host and pathogen proteins identified belong to specific functional categories, and several parasite gene families, while 33% of the P. vivax proteins have no reported function. Hemoglobin was significantly oxidized in both proteomes, and additional protein oxidation and nitration was detected in one of the two proteomes. Detailed analyses of these post-translational modifications are presented. The proteins identified here significantly expand the known P. vivax proteome and complexity of available host protein functionality underlying the host–parasite interactive biology, and reveal unsuspected oxidative modifications that may impact protein function. Biological significance Plasmodium vivax malaria is a serious neglected disease, causing an estimated 80 to 300 million cases annually in 95 countries. Infection can result in significant morbidity and possible death. P. vivax, unlike the much better-studied Plasmodium falciparum species, cannot be grown in long-term culture, has a dormant form in the liver called the hypnozoite stage, has a reticulocyte host–cell preference in the blood, and creates caveolae vesicle complexes at the surface of the infected reticulocyte

Plasmodium Parasitemia Associated With Increased Survival in Ebola Virus-Infected Patients.

PubMed

Rosenke, Kyle; Adjemian, Jennifer; Munster, Vincent J; Marzi, Andrea; Falzarano, Darryl; Onyango, Clayton O; Ochieng, Melvin; Juma, Bonventure; Fischer, Robert J; Prescott, Joseph B; Safronetz, David; Omballa, Victor; Owuor, Collins; Hoenen, Thomas; Groseth, Allison; Martellaro, Cynthia; van Doremalen, Neeltje; Zemtsova, Galina; Self, Joshua; Bushmaker, Trenton; McNally, Kristin; Rowe, Thomas; Emery, Shannon L; Feldmann, Friederike; Williamson, Brandi N; Best, Sonja M; Nyenswah, Tolbert G; Grolla, Allen; Strong, James E; Kobinger, Gary; Bolay, Fatorma K; Zoon, Kathryn C; Stassijns, Jorgen; Giuliani, Ruggero; de Smet, Martin; Nichol, Stuart T; Fields, Barry; Sprecher, Armand; Massaquoi, Moses; Feldmann, Heinz; de Wit, Emmie

2016-10-15

The ongoing Ebola outbreak in West Africa has resulted in 28 646 suspected, probable, and confirmed Ebola virus infections. Nevertheless, malaria remains a large public health burden in the region affected by the outbreak. A joint Centers for Disease Control and Prevention/National Institutes of Health diagnostic laboratory was established in Monrovia, Liberia, in August 2014, to provide laboratory diagnostics for Ebola virus. All blood samples from suspected Ebola virus-infected patients admitted to the Médecins Sans Frontières ELWA3 Ebola treatment unit in Monrovia were tested by quantitative real-time polymerase chain reaction for the presence of Ebola virus and Plasmodium species RNA. Clinical outcome in laboratory-confirmed Ebola virus-infected patients was analyzed as a function of age, sex, Ebola viremia, and Plasmodium species parasitemia. The case fatality rate of 1182 patients with laboratory-confirmed Ebola virus infections was 52%. The probability of surviving decreased with increasing age and decreased with increasing Ebola viral load. Ebola virus-infected patients were 20% more likely to survive when Plasmodium species parasitemia was detected, even after controlling for Ebola viral load and age; those with the highest levels of parasitemia had a survival rate of 83%. This effect was independent of treatment with antimalarials, as this was provided to all patients. Moreover, treatment with antimalarials did not affect survival in the Ebola virus mouse model. Plasmodium species parasitemia is associated with an increase in the probability of surviving Ebola virus infection. More research is needed to understand the molecular mechanism underlying this remarkable phenomenon and translate it into treatment options for Ebola virus infection. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Cytoadherence and sequestration in Plasmodium falciparum: defining the ties that bind.

PubMed

Sherman, Irwin W; Eda, Shigetoshi; Winograd, Enrique

2003-08-01

Infected erythrocytes containing the more mature stages of the human malaria Plasmodium falciparum may adhere to endothelial cells and uninfected red cells. These phenomena, called sequestration and rosetting, respectively, are involved in both host pathogenesis and parasite survival. This review provides a critical summary of recent advances in the characterization of the molecules of the infected red blood cell involved in adhesion, i.e. parasite-encoded molecules (PfEMP1, MESA, rifins, stevor, clag 9, histidine-rich protein), a modified host membrane protein (band 3) and exofacial exposure of phosphatidylserine, as well as receptors on the endothelium, i.e. thrombospondin, CD36, ICAM-1 (intercellular adhesion molecule), and chondroitin sulfate.

Detection of Plasmodium sp. in capybara.

PubMed

dos Santos, Leonilda Correia; Curotto, Sandra Mara Rotter; de Moraes, Wanderlei; Cubas, Zalmir Silvino; Costa-Nascimento, Maria de Jesus; de Barros Filho, Ivan Roque; Biondo, Alexander Welker; Kirchgatter, Karin

2009-07-07

In the present study, we have microscopically and molecularly surveyed blood samples from 11 captive capybaras (Hydrochaeris hydrochaeris) from the Sanctuary Zoo for Plasmodium sp. infection. One animal presented positive on blood smear by light microscopy. Polymerase chain reaction was carried out accordingly using a nested genus-specific protocol, which uses oligonucleotides from conserved sequences flanking a variable sequence region in the small subunit ribosomal RNA (ssrRNA) of all Plasmodium organisms. This revealed three positive animals. Products from two samples were purified and sequenced. The results showed less than 1% divergence between the two capybara sequences. When compared with GenBank sequences, a 55% similarity was obtained to Toxoplasma gondii and a higher similarity (73-77.2%) was found to ssrRNAs from Plasmodium species that infect reptile, avian, rodents, and human beings. The most similar Plasmodium sequence was from Plasmodium mexicanum that infects lizards of North America, where around 78% identity was found. This work is the first report of Plasmodium in capybaras, and due to the low similarity with other Plasmodium species, we suggest it is a new species, which, in the future could be denominated "Plasmodium hydrochaeri".

Contribution of Plasmodium knowlesi to Multispecies Human Malaria Infections in North Sumatera, Indonesia.

PubMed

Lubis, Inke N D; Wijaya, Hendri; Lubis, Munar; Lubis, Chairuddin P; Divis, Paul C S; Beshir, Khalid B; Sutherland, Colin J

2017-04-01

As Indonesia works toward the goal of malaria elimination, information is lacking on malaria epidemiology from some western provinces. As a basis for studies of antimalarial efficacy, we set out to survey parasite carriage in 3 communities in North Sumatera Province. A combination of active and passive detection of infection was carried out among communities in Batubara, Langkat, and South Nias regencies. Finger-prick blood samples from consenting individuals of all ages provided blood films for microscopic examination and blood spots on filter paper. Plasmodium species were identified using nested polymerase chain reaction (PCR) of ribosomal RNA genes and a novel assay that amplifies a conserved sequence specific for the sicavar gene family of Plasmodium knowlesi. Of 3731 participants, 614 (16.5%) were positive for malaria parasites by microscopy. PCR detected parasite DNA in samples from 1169 individuals (31.3%). In total, 377 participants (11.8%) harbored P. knowlesi. Also present were Plasmodium vivax (14.3%), Plasmodium falciparum (10.5%) and Plasmodium malariae (3.4%). Amplification of sicavar is a specific and sensitive test for the presence of P. knowlesi DNA in humans. Subpatent and asymptomatic multispecies parasitemia is relatively common in North Sumatera, so PCR-based surveillance is required to support control and elimination activities. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Endothelin-1 Treatment Induces an Experimental Cerebral Malaria-Like Syndrome in C57BL/6 Mice Infected with Plasmodium berghei NK65.

PubMed

Martins, Yuri C; Freeman, Brandi D; Akide Ndunge, Oscar B; Weiss, Louis M; Tanowitz, Herbert B; Desruisseaux, Mahalia S

2016-11-01

Plasmodium berghei ANKA infection of C57BL/6 mice is a widely used model of experimental cerebral malaria (ECM). By contrast, the nonneurotropic P. berghei NK65 (PbN) causes severe malarial disease in C57BL/6 mice but does not cause ECM. Previous studies suggest that endothelin-1 (ET-1) contributes to the pathogenesis of ECM. In this study, we characterize the role of ET-1 on ECM vascular dysfunction. Mice infected with 10 6 PbN-parasitized red blood cells were treated with either ET-1 or saline from 2 to 8 days postinfection (dpi). Plasmodium berghei ANKA-infected mice served as the positive control. ET-1-treated PbN-infected mice exhibited neurological signs, hypothermia, and behavioral alterations characteristic of ECM, dying 4 to 8 dpi. Parasitemia was not affected by ET-1 treatment. Saline-treated PbN-infected mice did not display ECM, surviving until 12 dpi. ET-1-treated PbN-infected mice displayed leukocyte adhesion to the vascular endothelia and petechial hemorrhages throughout the brain at 6 dpi. Intravital microscopic images demonstrated significant brain arteriolar vessel constriction, decreased functional capillary density, and increased blood-brain barrier permeability. These alterations were not present in either ET-1-treated uninfected or saline-treated PbN-infected mice. In summary, ET-1 treatment of PbN-infected mice induced an ECM-like syndrome, causing brain vasoconstriction, adherence of activated leukocytes in the cerebral microvasculature, and blood-brain barrier leakage, indicating that ET-1 is involved in the genesis of brain microvascular alterations that are the hallmark of ECM. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Diagnosis of Plasmodium falciparum infection in man: detection of parasite antigens by ELISA*

PubMed Central

Mackey, L. J.; McGregor, I. A.; Paounova, N.; Lambert, P. H.

1982-01-01

An ELISA method has been developed for the diagnosis of Plasmodium falciparum infection in man. Parasites from in vitro cultures of P. falciparum were used as source of antigen for the solid phase and the source of specific antibody was immune Gambian sera; binding of antibody in antigen-coated wells was registered by means of alkaline phosphatase-conjugated anti-human IgG. Parasites were detected on the basis of inhibition of antibody-binding. The test was applied to the detection of parasites in human red blood cells (RBC) from in vitro cultures of P. falciparum and in RBC from infected Gambians; RBC from 100 Geneva blood donors served as normal, uninfected controls. In titration experiments, the degree of antibody-binding inhibition correlated with the number of parasites in the test RBC. Parasites were detected at a level of 8 parasites/106 RBC. Samples of RBC were tested from 126 Gambians with microscopically proven infection; significant antibody-binding inhibition was found in 86% of these cases, where parasitaemia ranged from 10 to 125 000/μl of blood. The presence of high-titre antibody in the test preparations was found to reduce the sensitivity of parasite detection in infected RBC from in vitro cultures mixed with equal volumes of different antibody-containing sera. The sensitivity was restored in most cases by recovering the RBC by centrifugation before testing. In a preliminary experiment, there was no significant difference in antibody-binding inhibition using fresh infected RBC and RBC dried on filter-paper and recovered by elution, although there was greater variation in the latter samples. PMID:7044589

Natural Plasmodium infection in monkeys in the state of Rondônia (Brazilian Western Amazon)

PubMed Central

2013-01-01

Background Simian malaria is still an open question concerning the species of Plasmodium parasites and species of New World monkeys susceptible to the parasites. In addition, the lingering question as to whether these animals are reservoirs for human malaria might become important especially in a scenario of eradication of the disease. To aid in the answers to these questions, monkeys were surveyed for malaria parasite natural infection in the Amazonian state of Rondônia, Brazil, a state with intense environmental alterations due to human activities, which facilitated sampling of the animals. Methods Parasites were detected and identified in DNA from blood of monkeys, by PCR with primers for the 18S rRNA, CSP and MSP1 genes and sequencing of the amplified fragments. Multiplex PCR primers for the 18S rRNA genes were designed for the parasite species Plasmodium falciparum and Plasmodium vivax, Plasmodium malariae/Plasmodium brasilianum and Plasmodium simium. Results An overall infection rate of 10.9% was observed or 20 out 184 monkey specimens surveyed, mostly by P. brasilianum. However, four specimens of monkeys were found infected with P. falciparum, two of them doubly infected with P. brasilianum and P. falciparum. In addition, a species of monkey of the family Aotidae, Aotus nigriceps, is firstly reported here naturally infected with P. brasilianum. None of the monkeys surveyed was found infected with P. simium/P. vivax. Conclusion The rate of natural Plasmodium infection in monkeys in the Brazilian state of Rondônia is in line with previous surveys of simian malaria in the Amazon region. The fact that a monkey species was found that had not previously been described to harbour malaria parasites indicates that the list of monkey species susceptible to Plasmodium infection is yet to be completed. Furthermore, finding monkeys in the region infected with P. falciparum clearly indicates parasite transfer from humans to the animals. Whether this parasite can be

Raman acoustic levitation spectroscopy of red blood cells and Plasmodium falciparum trophozoites.

PubMed

Puskar, Ljiljana; Tuckermann, Rudolf; Frosch, Torsten; Popp, Jürgen; Ly, Vanalysa; McNaughton, Don; Wood, Bayden R

2007-09-01

Methods to probe the molecular structure of living cells are of paramount importance in understanding drug interactions and environmental influences in these complex dynamical systems. The coupling of an acoustic levitation device with a micro-Raman spectrometer provides a direct molecular probe of cellular chemistry in a containerless environment minimizing signal attenuation and eliminating the affects of adhesion to walls and interfaces. We show that the Raman acoustic levitation spectroscopic (RALS) approach can be used to monitor the heme dynamics of a levitated 5 microL suspension of red blood cells and to detect hemozoin in malaria infected cells. The spectra obtained have an excellent signal-to-noise ratio and demonstrate for the first time the utility of the technique as a diagnostic and monitoring tool for minute sample volumes of living animal cells.

On the birefringence of healthy and malaria-infected red blood cells

NASA Astrophysics Data System (ADS)

Dharmadhikari, Aditya K.; Basu, Himanish; Dharmadhikari, Jayashree A.; Sharma, Shobhona; Mathur, Deepak

2013-12-01

The birefringence of a red blood cell (RBC) is quantitatively monitored as it becomes infected by a malarial parasite. Large changes occur in the cell's refractive index at different stages of malarial infection. The observed rotation of an optically trapped, malaria-infected RBC is not a simple function of shape distortion: the malarial parasite is found to itself exercise a profound influence on the rotational dynamics by inducing stage-specific birefringence. Our measurements shed new light on the competition between shape- and form-birefringence in RBCs. We demonstrate the possibility of using birefringence to establish very early stages of infected parasites and of assessing various factors that contribute to birefringence in normal and infected cells. Our results have implications for the development and use of noninvasive techniques of quantifying changes in cell properties induced by malaria disease pathology.

Assessment of prion reduction filters in decreasing infectivity of ultracentrifuged 263K scrapie-infected brain homogenates in "spiked" human blood and red blood cells.

PubMed

Cardone, Franco; Sowemimo-Coker, Samuel; Abdel-Haq, Hanin; Sbriccoli, Marco; Graziano, Silvia; Valanzano, Angelina; Berardi, Vito Angelo; Galeno, Roberta; Puopolo, Maria; Pocchiari, Maurizio

2014-04-01

The safety of red blood cells (RBCs) is of concern because of the occurrence of four transfusion-transmitted variant Creutzfeldt-Jakob disease (vCJD) cases in the United Kingdom. The absence of validated screening tests requires the use of procedures to remove prions from blood to minimize the risk of transmission. These procedures must be validated using infectious prions in a form that is as close as possible to one in blood. Units of human whole blood (WB) and RBCs were spiked with high-speed supernatants of 263K scrapie-infected hamster brain homogenates. Spiked samples were leukoreduced and then passed through prion-removing filters (Pall Corporation). In another experiment, RBCs from 263K scrapie-infected hamsters were treated as above, and residual infectivity was measured by bioassay. The overall removal of infectivity by the filters from prion-spiked WB and RBCs was approximately two orders of magnitude. No infectivity was detected in filtered hamster RBCs endogenously infected with scrapie. The use of prion-removing filters may help to reduce the risk of transfusion-transmitted vCJD. To avoid overestimation of prion removal efficiency in validation studies, it may be more appropriate to use supernates from ultracentrifugation of scrapie-infected hamster brain homogenate rather than the current standard brain homogenates. © 2013 American Association of Blood Banks.

Intravital Observation of Plasmodium berghei Sporozoite Infection of the Liver

PubMed Central

Engelmann, Sabine; Zougbédé, Sergine; Stange, Jörg; Ng, Bruce; Matuschewski, Kai; Liebes, Leonard; Yee, Herman

2005-01-01

Plasmodium sporozoite invasion of liver cells has been an extremely elusive event to study. In the prevailing model, sporozoites enter the liver by passing through Kupffer cells, but this model was based solely on incidental observations in fixed specimens and on biochemical and physiological data. To obtain direct information on the dynamics of sporozoite infection of the liver, we infected live mice with red or green fluorescent Plasmodium berghei sporozoites and monitored their behavior using intravital microscopy. Digital recordings show that sporozoites entering a liver lobule abruptly adhere to the sinusoidal cell layer, suggesting a high-affinity interaction. They glide along the sinusoid, with or against the bloodstream, to a Kupffer cell, and, by slowly pushing through a constriction, traverse across the space of Disse. Once inside the liver parenchyma, sporozoites move rapidly for many minutes, traversing several hepatocytes, until ultimately settling within a final one. Migration damage to hepatocytes was confirmed in liver sections, revealing clusters of necrotic hepatocytes adjacent to structurally intact, sporozoite-infected hepatocytes, and by elevated serum alanine aminotransferase activity. In summary, malaria sporozoites bind tightly to the sinusoidal cell layer, cross Kupffer cells, and leave behind a trail of dead hepatocytes when migrating to their final destination in the liver. PMID:15901208

Association of Plasmodium falciparum with Human Endothelial Cells in vitro

PubMed Central

Utter, Christopher; Serrano, Adelfa E.; Glod, John W.; Leibowitz, Michael J.

2017-01-01

Endothelial abnormalities play a critical role in the pathogenesis of malaria caused by the human pathogen, Plasmodium falciparum. In serious infections and especially in cerebral malaria, red blood cells infected with the parasite are sequestered in small venules in various organs, resulting in endothelial activation and vascular occlusion, which are believed to be largely responsible for the morbidity and mortality caused by this infection, especially in children. We demonstrate that after incubation with infected red blood cells (iRBCs), cultured human umbilical vein endothelial cells (HUVECs) contain parasite protein, genomic DNA, and RNA, as well as intracellular vacuoles with apparent parasite-derived material, but not engulfed or adherent iRBCs. The association of this material with the HUVECs is observed over 96 hours after removal of iRBCs. This phenomenon may occur in endothelial cells in vivo by the process of trogocytosis, in which transfer of material between cells depends on direct cell contact. This process may contribute to the endothelial activation and disruption involved in the pathogenesis of cerebral malaria. PMID:28656007

Monitoring the uptake of glycosphingolipids in Plasmodium falciparum-infected erythrocytes using both fluorescence microscopy and capillary electrophoresis with laser-induced fluorescence detection

PubMed Central

Essaka, David C.; White, John; Rathod, Pradip; Whitmore, Colin D.; Hindsgaul, Ole; Palcic, Monica M.

2010-01-01

The metabolism of glycosphingolipids by the malaria-causing parasite Plasmodium falciparum plays an important role in the progression of the disease. We report a new and highly sensitive method to monitor the uptake of glycosphingolipids in infected red blood cells (iRBCs). A tetramethylrhodamine-labeled glycosphingolipid (GM1-TMR) was used as a substrate. Uptake was demonstrated by fluorescence microscopy. The iRBCs were lysed with a 15% solution of saponin and washed with phosphate buffered saline to release intact parasites. The parasites were further lysed and the resulting homogenates were analyzed by capillary electrophoresis with laser-induced fluorescence detection. The lysate from erythrocytes infected at 1% parasitemia generated a signal twenty standard deviations larger than uninfected erythrocytes, which suggests that relatively low infection levels can be studied with this technique. PMID:21043509

Automatic detection of malaria parasite in blood images using two parameters.

PubMed

Kim, Jong-Dae; Nam, Kyeong-Min; Park, Chan-Young; Kim, Yu-Seop; Song, Hye-Jeong

2015-01-01

Malaria must be diagnosed quickly and accurately at the initial infection stage and treated early to cure it properly. The malaria diagnosis method using a microscope requires much labor and time of a skilled expert and the diagnosis results vary greatly between individual diagnosticians. Therefore, to be able to measure the malaria parasite infection quickly and accurately, studies have been conducted for automated classification techniques using various parameters. In this study, by measuring classification technique performance according to changes of two parameters, the parameter values were determined that best distinguish normal from plasmodium-infected red blood cells. To reduce the stain deviation of the acquired images, a principal component analysis (PCA) grayscale conversion method was used, and as parameters, we used a malaria infected area and a threshold value used in binarization. The parameter values with the best classification performance were determined by selecting the value (72) corresponding to the lowest error rate on the basis of cell threshold value 128 for the malaria threshold value for detecting plasmodium-infected red blood cells.

Retention of Plasmodium falciparum ring-infected erythrocytes in the slow, open microcirculation of the human spleen.

PubMed

Safeukui, Innocent; Correas, Jean-Michel; Brousse, Valentine; Hirt, Déborah; Deplaine, Guillaume; Mulé, Sébastien; Lesurtel, Mickael; Goasguen, Nicolas; Sauvanet, Alain; Couvelard, Anne; Kerneis, Sophie; Khun, Huot; Vigan-Womas, Inès; Ottone, Catherine; Molina, Thierry Jo; Tréluyer, Jean-Marc; Mercereau-Puijalon, Odile; Milon, Geneviève; David, Peter H; Buffet, Pierre A

2008-09-15

The current paradigm in Plasmodium falciparum malaria pathogenesis states that young, ring-infected erythrocytes (rings) circulate in peripheral blood and that mature stages are sequestered in the vasculature, avoiding clearance by the spleen. Through ex vivo perfusion of human spleens, we examined the interaction of this unique blood-filtering organ with P falciparum-infected erythrocytes. As predicted, mature stages were retained. However, more than 50% of rings were also retained and accumulated upstream from endothelial sinus wall slits of the open, slow red pulp microcirculation. Ten percent of rings were retained at each spleen passage, a rate matching the proportion of blood flowing through the slow circulatory compartment established in parallel using spleen contrast-enhanced ultrasonography in healthy volunteers. Rings displayed a mildly but significantly reduced elongation index, consistent with a retention process, due to their altered mechanical properties. This raises the new paradigm of a heterogeneous ring population, the less deformable subset being retained in the spleen, thereby reducing the parasite biomass that will sequester in vital organs, influencing the risk of severe complications, such as cerebral malaria or severe anemia. Cryptic ring retention uncovers a new role for the spleen in the control of parasite density, opening novel intervention opportunities.

Wolbachia increases susceptibility to Plasmodium infection in a natural system.

PubMed

Zélé, F; Nicot, A; Berthomieu, A; Weill, M; Duron, O; Rivero, A

2014-03-22

Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia-mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito-Wolbachia-Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones.

Anti-erythrocyte antibodies may contribute to anaemia in Plasmodium vivax malaria by decreasing red blood cell deformability and increasing erythrophagocytosis.

PubMed

Mourão, Luiza Carvalho; Roma, Paula Magda da Silva; Sultane Aboobacar, Jamila da Silva; Medeiros, Camila Maia Pantuzzo; de Almeida, Zélia Barbosa; Fontes, Cor Jesus Fernandes; Agero, Ubirajara; de Mesquita, Oscar Nassif; Bemquerer, Marcelo Porto; Braga, Érika Martins

2016-08-04

Plasmodium vivax accounts for the majority of human malaria infections outside Africa and is being increasingly associated in fatal outcomes with anaemia as one of the major complications. One of the causes of malarial anaemia is the augmented removal of circulating non-infected red blood cells (nRBCs), an issue not yet fully understood. High levels of auto-antibodies against RBCs have been associated with severe anaemia and reduced survival of nRBCs in patients with falciparum malaria. Since there are no substantial data about the role of those antibodies in vivax malaria, this study was designed to determine whether or not auto-antibodies against erythrocytes are involved in nRBC clearance. Moreover, the possible immune mechanisms elicited by them that may be associated to induce anaemia in P. vivax infection was investigated. Concentrations of total IgG were determined by sandwich ELISA in sera from clinically well-defined groups of P. vivax-infected patients with or without anaemia and in healthy controls never exposed to malaria, whereas the levels of specific IgG to nRBCs were determined by cell-ELISA. Erythrophagocytosis assay was used to investigate the ability of IgGs purified from each studied pooled sera in enhancing nRBC in vitro clearance by THP-1 macrophages. Defocusing microscopy was employed to measure the biomechanical modifications of individual nRBCs opsonized by IgGs purified from each group. Anaemic patients had higher levels of total and specific anti-RBC antibodies in comparison to the non-anaemic ones. Opsonization with purified IgG from anaemic patients significantly enhanced RBCs in vitro phagocytosis by THP-1 macrophages. Auto-antibodies purified from anaemic patients decreased the nRBC dynamic membrane fluctuations suggesting a possible participation of such antibodies in the perturbation of erythrocyte flexibility and morphology integrity maintenance. These findings revealed that vivax-infected patients with anaemia have increased

Decreased level of 2,3-diphosphoglycerate and alteration of structural integrity in erythrocytes infected with Plasmodium falciparum in vitro.

PubMed

Dubey, M L; Hegde, Ramakrishna; Ganguly, N K; Mahajan, R C

2003-04-01

2,3-Diphosphoglycerate (2,3-DPG), an intracellular metabolite of glycolytic pathway is known to affect the oxygen binding capacity of haemoglobin and mechanical properties of the red blood cells. 2,3-DPG levels have been reported to be elevated during anaemic conditions including visceral leishmaniasis. 2,3-DPG activity in P. falciparum infected red blood cells, particularly in cells infected with different stages of the parasite and its relationship with structural integrity of the cells is not known. Chloroquine sensitive and resistant strains of P. falciparum were cultured in vitro and synchronized cultures of ring, trophozoite and schizont stage rich cells along with the uninfected control erythrocytes were assayed for 2,3-DPG activity and osmotic fragility. It was observed that in both the strains, in infected erythrocytes the 2,3-DPG activity gradually decreased and osmotic fragility gradually increased as the parasite matured from ring to schizont stage. The decrease in 2,3-DPG may probably be due to increased pyruvate kinase activity of parasite origin, which has been shown in erythrocytes infected with several species of Plasmodium. The absence of compensatory increase in 2,3-DPG in P. falciparum infected erythrocytes may aggravate hypoxia due to anaemia in malaria and probably may contribute to hypoxia in cerebral malaria. As 2,3-DPG was not found to be increased in erythrocytes parasitized with P. falciparum, the increased osmotic fragility observed in these cells is not due to increased 2,3-DPG as has been suggested in visceral leishmaniasis.

Interactions between the intestinal flagellates Giardia muris and Spironucleus muris and the blood parasites Babesia microti, Plasmodium yoelii and Plasmodium berghei in mice.

PubMed

Brett, S J; Cox, F E

1982-08-01

In mice infected with the intestinal flagellates Giardia muris or Spironucleus muris, together with the blood parasites Babesia microti or Plasmodium yoelii, there is a temporary decrease of flagellate cyst output coincident with the peak of the blood parasite infections, followed by a rapid return to normal levels. This decrease in cyst output is correlated with decreased numbers of trophozoites in the small intestine. The effect on S. muris is more marked than that on G. muris. Neither blood parasites has any effect on the total duration of the flagellate infection and the flagellates do not affect the blood parasites. In mice infected with G. muris or S. muris and P. berghei there is also a decrease in cyst output but this is less apparent than in infections with B. microti or P. yoelii because of the fatal nature of the P. berghei infection. It is suggested that the decrease in cyst output is probably due to changes in the contents of the small intestine or to non-specific immunological factors rather than to specific immunological changes.

Challenges of assessing the clinical efficacy of asexual blood-stage Plasmodium falciparum malaria vaccines.

PubMed

Sheehy, Susanne H; Douglas, Alexander D; Draper, Simon J

2013-09-01

In the absence of any highly effective vaccine candidate against Plasmodium falciparum malaria, it remains imperative for the field to pursue all avenues that may lead to the successful development of such a formulation. The development of a subunit vaccine targeting the asexual blood-stage of Plasmodium falciparum malaria infection has proven particularly challenging with only limited success to date in clinical trials. However, only a fraction of potential blood-stage vaccine antigens have been evaluated as targets, and a number of new promising candidate antigen formulations and delivery platforms are approaching clinical development. It is therefore essential that reliable and sensitive methods of detecting, or ruling out, even modest efficacy of blood-stage vaccines in small clinical trials be established. In this article we evaluate the challenges facing blood-stage vaccine developers, assess the appropriateness and limitations of various in vivo approaches for efficacy assessment and suggest future directions for the field.

Medical comorbidities and perioperative allogeneic red blood cell transfusion are risk factors for surgical site infection after shoulder arthroplasty.

PubMed

Everhart, Joshua S; Bishop, Julie Y; Barlow, Jonathan D

2017-11-01

Multiple perioperative factors have been implicated in infection risk after shoulder arthroplasty. The purpose of this study was to determine surgical site infection (SSI) risk due to medical comorbidities or blood transfusion after primary or revision shoulder arthroplasty. Comprehensive data on medical comorbidities, surgical indication, perioperative transfusion, and SSI were obtained for 707 patients who underwent primary or revision hemiarthroplasty or total shoulder arthroplasty in a single hospital system. Multivariate Poisson regression was used to determine the independent association between allogeneic red blood cell transfusion, medical comorbidities, and SSI after controlling for procedure. The SSI rate was 1.9% for primary hemiarthroplasties and 1.3% for primary total shoulder arthroplasties. Among patients without prior shoulder infection, revision arthroplasty or prior open reduction and internal fixation had higher SSI risk than primary arthroplasties (incidence risk ratio [IRR], 11.4; 95% confidence interval [CI], 3.84-34.0; P < .001); among primary arthroplasties, SSI risk factors included male gender (IRR, 60.0; CI, 4.39-819; P = .002), rheumatoid arthritis (IRR, 8.63; CI, 1.84-40.4; P = .006), and long-term corticosteroid use (IRR, 37.4; CI, 5.79-242; P < .001). Perioperative allogeneic red blood cell transfusion significantly increased SSI risk and was dose dependent (IRR, 1.68 per unit packed red blood cell; CI, 1.21-2.35; P = .002). Gender, rheumatoid arthritis, and long-term (>1 year) corticosteroid use affect SSI risk after shoulder arthroplasty. Revision surgery, particularly in the setting of prior infection, increased risk of future infection. Finally, allogeneic red blood cell transfusion increases SSI risk after shoulder arthroplasty in a dose-dependent manner. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

High-resolution three-dimensional imaging of red blood cells parasitized by Plasmodium falciparum and in situ hemozoin crystals using optical diffraction tomography

NASA Astrophysics Data System (ADS)

Kim, Kyoohyun; Yoon, HyeOk; Diez-Silva, Monica; Dao, Ming; Dasari, Ramachandra R.; Park, YongKeun

2014-01-01

We present high-resolution optical tomographic images of human red blood cells (RBC) parasitized by malaria-inducing Plasmodium falciparum (Pf)-RBCs. Three-dimensional (3-D) refractive index (RI) tomograms are reconstructed by recourse to a diffraction algorithm from multiple two-dimensional holograms with various angles of illumination. These 3-D RI tomograms of Pf-RBCs show cellular and subcellular structures of host RBCs and invaded parasites in fine detail. Full asexual intraerythrocytic stages of parasite maturation (ring to trophozoite to schizont stages) are then systematically investigated using optical diffraction tomography algorithms. These analyses provide quantitative information on the structural and chemical characteristics of individual host Pf-RBCs, parasitophorous vacuole, and cytoplasm. The in situ structural evolution and chemical characteristics of subcellular hemozoin crystals are also elucidated.

Susceptibility to Plasmodium liver stage infection is altered by hepatocyte polyploidy.

PubMed

Austin, Laura S; Kaushansky, Alexis; Kappe, Stefan H I

2014-05-01

Plasmodium parasites infect hepatocytes of their mammalian hosts and undergo obligate liver stage development. The specific host cell attributes that are important for liver infection remain largely unknown. Several host signalling pathways are perturbed in infected hepatocytes, some of which are important in the generation of hepatocyte polyploidy. To test the functional consequence of polyploidy on liver infection, we infected hepatocytes with the rodent malaria parasite Plasmodium yoelii both in vitro and in vivo and examined the ploidy of infected and uninfected hepatocytes by flow cytometry. In both hepatoma cell lines and in the mouse liver, the fraction of polyploid cells was higher in the infected cell population than in the uninfected cell population. When the data were reanalysed by comparing the extent of Plasmodium infection within each ploidy subset, we found that infection rates were elevated in more highly polyploid cells and lower in diploid cells. Furthermore, we found that the parasite's preference for host cells with high ploidy is conserved among rodent malaria species and the human malaria parasite Plasmodium falciparum. This parasite preference for host cells of high ploidy cannot be explained by differences in hepatocyte size or DNA replication. We conclude that Plasmodium preferentially infects and develops in polyploid hepatocytes. © 2014 John Wiley & Sons Ltd.

Susceptibility to Plasmodium liver stage infection is altered by hepatocyte polyploidy

PubMed Central

Austin, Laura S.; Kaushansky, Alexis; Kappe, Stefan H.I.

2014-01-01

Summary Plasmodium parasites infect hepatocytes of their mammalian hosts and within undergo obligate liver stage development. The specific host cell attributes that are important for liver infection remain largely unknown. Several host signaling pathways are perturbed in infected hepatocytes, some of which are important in the generation of hepatocyte polyploidy. To test the functional consequence of polyploidy in liver infection, we infected hepatocytes with the rodent malaria parasite Plasmodium yoelii both in vitro and in vivo and examined the ploidy of infected and uninfected hepatocytes by flow cytometry. In both hepatoma cell lines and in the mouse liver, the fraction of polyploid cells was higher in the infected cell population than in the uninfected cell population. When the data were reanalyzed by comparing the extent of Plasmodium infection within each ploidy subset, we found that infection rates were elevated in more highly polyploid cells and lower in diploid cells. Furthermore, we found that the parasite’s preference for host cells with high ploidy is conserved among rodent malaria species and the human malaria parasite Plasmodium falciparum. This parasite preference for host cells of high ploidy cannot be explained by differences in hepatocyte size or DNA replication. We conclude that Plasmodium preferentially infects and develops in polyploid hepatocytes. PMID:24612025

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

Trafficking of the signature protein of intra-erythrocytic Plasmodium berghei-induced structures, IBIS1, to P. falciparum Maurer's clefts.

PubMed

Petersen, Wiebke; Matuschewski, Kai; Ingmundson, Alyssa

2015-01-01

Remodeling of the host red blood cell by Plasmodium falciparum is well established and crucial for infection and parasite virulence. Host cell modifications are not exclusive to human Plasmodium parasites and also occur in hepatocytes and erythrocytes infected with murine Plasmodium parasites. The recently described intra-erythrocytic P. berghei-induced structures (IBIS) share similarities to P. falciparum Maurer's clefts. It is shown here that a potential candidate IBIS1 homologue in P. falciparum, PfHYP12 (PF3D7_1301400), is partially exported into the erythrocyte cytoplasm. To analyze a potential similarity between IBIS and Maurer's clefts we expressed the signature protein of IBIS in P. falciparum parasites. Visualization of the tagged protein revealed that PbIBIS1 can be exported by P. falciparum and localizes to Maurer's clefts in P. falciparum-infected erythrocytes, which indicates that IBIS and Maurer's clefts may be evolutionarily conserved parasite-induced structures in infected erythrocytes. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Life cycle-dependent cytoskeletal modifications in Plasmodium falciparum infected erythrocytes.

PubMed

Shi, Hui; Liu, Zhuo; Li, Ang; Yin, Jing; Chong, Alvin G L; Tan, Kevin S W; Zhang, Yong; Lim, Chwee Teck

2013-01-01

Plasmodium falciparum infection of human erythrocytes is known to result in the modification of the host cell cytoskeleton by parasite-coded proteins. However, such modifications and corresponding implications in malaria pathogenesis have not been fully explored. Here, we probed the gradual modification of infected erythrocyte cytoskeleton with advancing stages of infection using atomic force microscopy (AFM). We reported a novel strategy to derive accurate and quantitative information on the knob structures and their connections with the spectrin network by performing AFM-based imaging analysis of the cytoplasmic surface of infected erythrocytes. Significant changes on the red cell cytoskeleton were observed from the expansion of spectrin network mesh size, extension of spectrin tetramers and the decrease of spectrin abundance with advancing stages of infection. The spectrin network appeared to aggregate around knobs but also appeared sparser at non-knob areas as the parasite matured. This dramatic modification of the erythrocyte skeleton during the advancing stage of malaria infection could contribute to the loss of deformability of the infected erythrocyte.

Co-incidental Plasmodium Knowlesi and Mucormycosis infections presenting with acute kidney injury and lower gastrointestinal bleeding.

PubMed

Ramaswami, Arunachalam; Pisharam, Jayakrishnan K; Aung, Hla; Ghazala, Kafeel; Maboud, Khalil; Chong, Vui Heng; Tan, Jackson

2013-01-01

Plasmodium knowlesi is frequently reported in Southeast Asian countries and is now widely regarded as the fifth malarial parasite. Mucormycosis is a rare fungal infection that can occur in patients with a weakened immune system. We report a case of acute kidney injury secondary to Plasmodium knowlesi malaria infection and mucormycosis fungal infection. In addition, the patient also had lower gastrointestinal bleeding from invasive gastrointestinal mucormycosis. P. knowlesi infection was diagnosed by blood film and mucormycosis was diagnosed by histopathological examination of biopsy specimen of the colon. The patient recovered with antimalarial treatment (Quinine), antifungal treatment (Lipophilic Amphotericin), and supportive hemodialysis treatment. We hypothesize that P. knowlesi malarial infection can lower the immunologic threshold and predisposes vulnerable individuals to rare disseminated fungal infections. To the best of our knowledge, this is the first P. Knowlesi malaria-associated invasive fungal infection reported in the literature.

Severe malaria - a case of fatal Plasmodium knowlesi infection with post-mortem findings: a case report

PubMed Central

2010-01-01

Background Zoonotic malaria caused by Plasmodium knowlesi is an important, but newly recognized, human pathogen. For the first time, post-mortem findings from a fatal case of knowlesi malaria are reported here. Case presentation A formerly healthy 40 year-old male became symptomatic 10 days after spending time in the jungle of North Borneo. Four days later, he presented to hospital in a state of collapse and died within two hours. He was hyponatraemic and had elevated blood urea, potassium, lactate dehydrogenase and amino transferase values; he was also thrombocytopenic and eosinophilic. Dengue haemorrhagic shock was suspected and a post-mortem examination performed. Investigations for dengue virus were negative. Blood for malaria parasites indicated hyperparasitaemia and single species P. knowlesi infection was confirmed by nested-PCR. Macroscopic pathology of the brain and endocardium showed multiple petechial haemorrhages, the liver and spleen were enlarged and lungs had features consistent with ARDS. Microscopic pathology showed sequestration of pigmented parasitized red blood cells in the vessels of the cerebrum, cerebellum, heart and kidney without evidence of chronic inflammatory reaction in the brain or any other organ examined. Brain sections were negative for intracellular adhesion molecule-1. The spleen and liver had abundant pigment containing macrophages and parasitized red blood cells. The kidney had evidence of acute tubular necrosis and endothelial cells in heart sections were prominent. Conclusions The overall picture in this case was one of systemic malaria infection that fit the WHO classification for severe malaria. Post-mortem findings in this case were unexpectedly similar to those that define fatal falciparum malaria, including cerebral pathology. There were important differences including the absence of coma despite petechial haemorrhages and parasite sequestration in the brain. These results suggest that further study of knowlesi malaria

High-resolution three-dimensional imaging of red blood cells parasitized by Plasmodium falciparum and in situ hemozoin crystals using optical diffraction tomography

PubMed Central

Kim, Kyoohyun; Yoon, HyeOk; Diez-Silva, Monica; Dao, Ming; Dasari, Ramachandra R.

2013-01-01

Abstract. We present high-resolution optical tomographic images of human red blood cells (RBC) parasitized by malaria-inducing Plasmodium falciparum (Pf)-RBCs. Three-dimensional (3-D) refractive index (RI) tomograms are reconstructed by recourse to a diffraction algorithm from multiple two-dimensional holograms with various angles of illumination. These 3-D RI tomograms of Pf-RBCs show cellular and subcellular structures of host RBCs and invaded parasites in fine detail. Full asexual intraerythrocytic stages of parasite maturation (ring to trophozoite to schizont stages) are then systematically investigated using optical diffraction tomography algorithms. These analyses provide quantitative information on the structural and chemical characteristics of individual host Pf-RBCs, parasitophorous vacuole, and cytoplasm. The in situ structural evolution and chemical characteristics of subcellular hemozoin crystals are also elucidated. PMID:23797986

Vital and dispensable roles of Plasmodium multidrug resistance transporters during blood- and mosquito-stage development.

PubMed

Rijpma, Sanna R; van der Velden, Maarten; Annoura, Takeshi; Matz, Joachim M; Kenthirapalan, Sanketha; Kooij, Taco W A; Matuschewski, Kai; van Gemert, Geert-Jan; van de Vegte-Bolmer, Marga; Siebelink-Stoter, Rianne; Graumans, Wouter; Ramesar, Jai; Klop, Onny; Russel, Frans G M; Sauerwein, Robert W; Janse, Chris J; Franke-Fayard, Blandine M; Koenderink, Jan B

2016-07-01

Multidrug resistance (MDR) proteins belong to the B subfamily of the ATP Binding Cassette (ABC) transporters, which export a wide range of compounds including pharmaceuticals. In this study, we used reverse genetics to study the role of all seven Plasmodium MDR proteins during the life cycle of malaria parasites. Four P. berghei genes (encoding MDR1, 4, 6 and 7) were refractory to deletion, indicating a vital role during blood stage multiplication and validating them as potential targets for antimalarial drugs. Mutants lacking expression of MDR2, MDR3 and MDR5 were generated in both P. berghei and P. falciparum, indicating a dispensable role for blood stage development. Whereas P. berghei mutants lacking MDR3 and MDR5 had a reduced blood stage multiplication in vivo, blood stage growth of P. falciparum mutants in vitro was not significantly different. Oocyst maturation and sporozoite formation in Plasmodium mutants lacking MDR2 or MDR5 was reduced. Sporozoites of these P. berghei mutants were capable of infecting mice and life cycle completion, indicating the absence of vital roles during liver stage development. Our results demonstrate vital and dispensable roles of MDR proteins during blood stages and an important function in sporogony for MDR2 and MDR5 in both Plasmodium species. © 2016 John Wiley & Sons Ltd.

Structural Basis for the ABO Blood-Group Dependence of Plasmodium falciparum Rosetting

PubMed Central

Hessel, Audrey; Raynal, Bertrand; England, Patrick; Cohen, Jacques H.; Bertrand, Olivier; Peyrard, Thierry; Bentley, Graham A.; Lewit-Bentley, Anita; Mercereau-Puijalon, Odile

2012-01-01

The ABO blood group influences susceptibility to severe Plasmodium falciparum malaria. Recent evidence indicates that the protective effect of group O operates by virtue of reduced rosetting of infected red blood cells (iRBCs) with uninfected RBCs. Rosetting is mediated by a subgroup of PfEMP1 adhesins, with RBC binding being assigned to the N-terminal DBL1α1 domain. Here, we identify the ABO blood group as the main receptor for VarO rosetting, with a marked preference for group A over group B, which in turn is preferred to group O RBCs. We show that recombinant NTS-DBL1α1 and NTS-DBL1α1-CIDR1γ reproduce the VarO-iRBC blood group preference and document direct binding to blood group trisaccharides by surface plasmon resonance. More detailed RBC subgroup analysis showed preferred binding to group A1, weaker binding to groups A2 and B, and least binding to groups Ax and O. The 2.8 Å resolution crystal structure of the PfEMP1-VarO Head region, NTS-DBL1α1-CIDR1γ, reveals extensive contacts between the DBL1α1 and CIDR1γ and shows that the NTS-DBL1α1 hinge region is essential for RBC binding. Computer docking of the blood group trisaccharides and subsequent site-directed mutagenesis localized the RBC-binding site to the face opposite to the heparin-binding site of NTS-DBLα1. RBC binding involves residues that are conserved between rosette-forming PfEMP1 adhesins, opening novel opportunities for intervention against severe malaria. By deciphering the structural basis of blood group preferences in rosetting, we provide a link between ABO blood grouppolymorphisms and rosette-forming adhesins, consistent with the selective role of falciparum malaria on human genetic makeup. PMID:22807674

Colombian Anopheles triannulatus (Diptera: Culicidae) Naturally Infected with Plasmodium spp.

PubMed Central

Rosero, Doris A.; Naranjo-Diaz, Nelson; Alvarez, Natalí; Cienfuegos, Astrid V.; Luckhart, Shirley

2013-01-01

The role of Anopheles triannulatus as a local vector has not yet been defined for malaria-endemic regions of Colombia. Therefore, the aim of this work was to detect An. triannulatus naturally infected with Plasmodium spp., as an approximation to determining its importance as malaria vector in the country. A total of 510 An. triannulatus were collected in six malaria-endemic localities of NW and SE Colombia from January 2009 to March 2011. In the NW, two specimens were naturally infected; one with Plasmodium vivax VK247, collected biting on humans and the other with Plasmodium falciparum, collected resting on cattle. In the SE, two specimens were positive for P. falciparum. Although these results show An. triannulatus naturally infected with Plasmodium, further studies are recommended to demonstrate the epidemiological importance of this species in malaria-endemic regions of Colombia. PMID:27335865

Colombian Anopheles triannulatus (Diptera: Culicidae) Naturally Infected with Plasmodium spp.

PubMed

Rosero, Doris A; Naranjo-Diaz, Nelson; Alvarez, Natalí; Cienfuegos, Astrid V; Torres, Carolina; Luckhart, Shirley; Correa, Margarita M

2013-01-01

The role of Anopheles triannulatus as a local vector has not yet been defined for malaria-endemic regions of Colombia. Therefore, the aim of this work was to detect An. triannulatus naturally infected with Plasmodium spp., as an approximation to determining its importance as malaria vector in the country. A total of 510 An. triannulatus were collected in six malaria-endemic localities of NW and SE Colombia from January 2009 to March 2011. In the NW, two specimens were naturally infected; one with Plasmodium vivax VK247, collected biting on humans and the other with Plasmodium falciparum, collected resting on cattle. In the SE, two specimens were positive for P. falciparum. Although these results show An. triannulatus naturally infected with Plasmodium, further studies are recommended to demonstrate the epidemiological importance of this species in malaria-endemic regions of Colombia.

Image classification of unlabeled malaria parasites in red blood cells.

PubMed

Zheng Zhang; Ong, L L Sharon; Kong Fang; Matthew, Athul; Dauwels, Justin; Ming Dao; Asada, Harry

2016-08-01

This paper presents a method to detect unlabeled malaria parasites in red blood cells. The current "gold standard" for malaria diagnosis is microscopic examination of thick blood smear, a time consuming process requiring extensive training. Our goal is to develop an automate process to identify malaria infected red blood cells. Major issues in automated analysis of microscopy images of unstained blood smears include overlapping cells and oddly shaped cells. Our approach creates robust templates to detect infected and uninfected red cells. Histogram of Oriented Gradients (HOGs) features are extracted from templates and used to train a classifier offline. Next, the ViolaJones object detection framework is applied to detect infected and uninfected red cells and the image background. Results show our approach out-performs classification approaches with PCA features by 50% and cell detection algorithms applying Hough transforms by 24%. Majority of related work are designed to automatically detect stained parasites in blood smears where the cells are fixed. Although it is more challenging to design algorithms for unstained parasites, our methods will allow analysis of parasite progression in live cells under different drug treatments.

Resistance to malaria through structural variation of red blood cell invasion receptors

PubMed Central

Leffler, Ellen M.; Band, Gavin; Busby, George B.J.; Kivinen, Katja; Le, Quang Si; Clarke, Geraldine M.; Bojang, Kalifa A.; Conway, David J.; Jallow, Muminatou; Sisay-Joof, Fatoumatta; Bougouma, Edith C.; Mangano, Valentina D.; Modiano, David; Sirima, Sodiomon B.; Achidi, Eric; Apinjoh, Tobias O.; Marsh, Kevin; Ndila, Carolyne M.; Peshu, Norbert; Williams, Thomas N.; Drakeley, Chris; Manjurano, Alphaxard; Reyburn, Hugh; Riley, Eleanor; Kachala, David; Molyneux, Malcolm; Nyirongo, Vysaul; Taylor, Terrie; Thornton, Nicole; Tilley, Louise; Grimsley, Shane; Drury, Eleanor; Stalker, Jim; Cornelius, Victoria; Hubbart, Christina; Jeffreys, Anna E.; Rowlands, Kate; Rockett, Kirk A.; Spencer, Chris C.A.; Kwiatkowski, Dominic P.

2017-01-01

The malaria parasite Plasmodium falciparum invades human red blood cells via interactions between host and parasite surface proteins. By analyzing genome sequence data from human populations, including 1269 individuals from sub-Saharan Africa, we identify a diverse array of large copy number variants affecting the host invasion receptor genes GYPA and GYPB. We find that a nearby association with severe malaria is explained by a complex structural rearrangement involving the loss of GYPB and gain of two GYPB-A hybrid genes, which encode a serologically distinct blood group antigen known as Dantu. This variant reduces the risk of severe malaria by 40% and has recently risen in frequency in parts of Kenya, yet it appears to be absent from west Africa. These findings link structural variation of red blood cell invasion receptors with natural resistance to severe malaria. PMID:28522690

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

PubMed

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

2015-07-01

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

Plasmodium malariae and P. ovale genomes provide insights into malaria parasite evolution

PubMed Central

Rutledge, Gavin G.; Böhme, Ulrike; Sanders, Mandy; Reid, Adam J.; Cotton, James A.; Maiga-Ascofare, Oumou; Djimdé, Abdoulaye A.; Apinjoh, Tobias O.; Amenga-Etego, Lucas; Manske, Magnus; Barnwell, John W.; Renaud, François; Ollomo, Benjamin; Prugnolle, Franck; Anstey, Nicholas M.; Auburn, Sarah; Price, Ric N.; McCarthy, James S.; Kwiatkowski, Dominic P.; Newbold, Chris I.; Berriman, Matthew; Otto, Thomas D.

2017-01-01

Elucidation of the evolutionary history and interrelatedness of Plasmodium species that infect humans has been hampered by a lack of genetic information for three human-infective species: P. malariae and two P. ovale species (P. o. curtisi and P. o. wallikeri)1. These species are prevalent across most regions in which malaria is endemic2,3 and are often undetectable by light microscopy4, rendering their study in human populations difficult5. The exact evolutionary relationship of these species to the other human-infective species has been contested6,7. Using a new reference genome for P. malariae and a manually curated draft P. o. curtisi genome, we are now able to accurately place these species within the Plasmodium phylogeny. Sequencing of a P. malariae relative that infects chimpanzees reveals similar signatures of selection in the P. malariae lineage to another Plasmodium lineage shown to be capable of colonization of both human and chimpanzee hosts. Molecular dating suggests that these host adaptations occurred over similar evolutionary timescales. In addition to the core genome that is conserved between species, differences in gene content can be linked to their specific biology. The genome suggests that P. malariae expresses a family of heterodimeric proteins on its surface that have structural similarities to a protein crucial for invasion of red blood cells. The data presented here provide insight into the evolution of the Plasmodium genus as a whole. PMID:28117441

Detection of malaria infection in blood transfusion: a comparative study among real-time PCR, rapid diagnostic test and microscopy: sensitivity of Malaria detection methods in blood transfusion.

PubMed

Hassanpour, Gholamreza; Mohebali, Mehdi; Raeisi, Ahmad; Abolghasemi, Hassan; Zeraati, Hojjat; Alipour, Mohsen; Azizi, Ebrahim; Keshavarz, Hossein

2011-06-01

The transmission of malaria by blood transfusion was one of the first transfusion-transmitted infections recorded in the world. Transfusion-transmitted malaria may lead to serious problems because infection with Plasmodium falciparum may cause rapidly fatal death. This study aimed to compare real-time polymerase chain reaction (real-time PCR) with rapid diagnostic test (RDT) and light microscopy for the detection of Plasmodium spp. in blood transfusion, both in endemic and non-endemic areas of malaria disease in Iran. Two sets of 50 blood samples were randomly collected. One set was taken from blood samples donated in blood bank of Bandar Abbas, a city located in a malarious-endemic area, and the other set from Tehran, a non-endemic one. Light microscopic examination on both thin and thick smears, RDTs, and real-time PCR were performed on the blood samples and the results were compared. Thin and thick light microscopic examinations of all samples as well as RDT results were negative for Plasmodium spp. Two blood samples from endemic area were positive only with real-time PCR. It seems that real-time PCR as a highly sensitive method can be helpful for the confirmation of malaria infection in different units of blood transfusion organization especially in malaria-endemic areas where the majority of donors may be potentially infected with malaria parasites.

In vitro growth of Plasmodium falciparum in neonatal blood.

PubMed

Sauerzopf, Ulrich; Honkpehedji, Yabo J; Adgenika, Ayôla A; Feugap, Elianne N; Ngoma, Ghyslain Mombo; Mackanga, Jean-Rodolphe; Lötsch, Felix; Loembe, Marguerite M; Kremsner, Peter G; Mordmüller, Benjamin; Ramharter, Michael

2014-11-18

Children below the age of six months suffer less often from malaria than older children in sub-Saharan Africa. This observation is commonly attributed to the persistence of foetal haemoglobin (HbF), which is considered not to permit growth of Plasmodium falciparum and therefore providing protection against malaria. Since this concept has recently been challenged, this study evaluated the effect of HbF erythrocytes and maternal plasma on in vitro parasite growth of P. falciparum in Central African Gabon. Umbilical cord blood and peripheral maternal blood were collected at delivery at the Albert Schweitzer Hospital in Gabon. Respective erythrocyte suspension and plasma were used in parallel for in vitro culture. In vitro growth rates were compared between cultures supplemented with either maternal or cord erythrocytes. Plasma of maternal blood and cord blood was evaluated. Parasite growth rates were assessed by the standard HRP2-assay evaluating the increase of HRP2 concentration in Plasmodium culture. Culture of P. falciparum using foetal erythrocytes led to comparable growth rates (mean growth rate = 4.2, 95% CI: 3.5 - 5.0) as cultures with maternal red blood cells (mean growth rate =4.2, 95% CI: 3.4 - 5.0) and those from non-malaria exposed individuals (mean growth rate = 4.6, 95% CI: 3.8 - 5.5). Standard in vitro culture of P. falciparum supplemented with either maternal or foetal plasma showed both significantly lower growth rates than a positive control using non-malaria exposed donor plasma. These data challenge the concept of HbF serving as intrinsic inhibitor of P. falciparum growth in the first months of life. Erythrocytes containing HbF are equally permissive to P. falciparum growth in vitro. However, addition of maternal and cord plasma led to reduced in vitro growth which may translate to protection against clinical disease or show synergistic effects with HbF in vivo. Further studies are needed to elucidate the pathophysiology of innate and acquired

Trypanosoma vivax Adhesion to Red Blood Cells in Experimentally Infected Sheep

PubMed Central

Boada-Sucre, Alpidio A.; Rossi Spadafora, Marcello Salvatore; Tavares-Marques, Lucinda M.; Finol, Héctor J.; Reyna-Bello, Armando

2016-01-01

Trypanosomosis, a globally occurring parasitic disease, poses as a major obstacle to livestock production in tropical and subtropical regions resulting in tangible economic losses. In Latin America including Venezuela, trypanosomosis of ruminants is mainly caused by Trypanosoma vivax. Biologically active substances produced from trypanosomes, as well as host-trypanosome cellular interactions, contribute to the pathogenesis of anemia in an infection. The aim of this study was to examine with a scanning electron microscope the cellular interactions and alterations in ovine red blood cells (RBC) experimentally infected with T. vivax. Ovine infection resulted in changes of RBC shape as well as the formation of surface holes or vesicles. A frequent observation was the adhesion to the ovine RBC by the trypanosome's free flagellum, cell body, or attached flagellum in a process mediated by the filopodia emission from the trypanosome surface. The observed RBC alterations are caused by mechanical and biochemical damage from host-parasite interactions occurring in the bloodstream. The altered erythrocytes are prone to mononuclear phagocytic removal contributing to the hematocrit decrease during infection. PMID:27293960

Trypanosoma vivax Adhesion to Red Blood Cells in Experimentally Infected Sheep.

PubMed

Boada-Sucre, Alpidio A; Rossi Spadafora, Marcello Salvatore; Tavares-Marques, Lucinda M; Finol, Héctor J; Reyna-Bello, Armando

2016-01-01

Trypanosomosis, a globally occurring parasitic disease, poses as a major obstacle to livestock production in tropical and subtropical regions resulting in tangible economic losses. In Latin America including Venezuela, trypanosomosis of ruminants is mainly caused by Trypanosoma vivax. Biologically active substances produced from trypanosomes, as well as host-trypanosome cellular interactions, contribute to the pathogenesis of anemia in an infection. The aim of this study was to examine with a scanning electron microscope the cellular interactions and alterations in ovine red blood cells (RBC) experimentally infected with T. vivax. Ovine infection resulted in changes of RBC shape as well as the formation of surface holes or vesicles. A frequent observation was the adhesion to the ovine RBC by the trypanosome's free flagellum, cell body, or attached flagellum in a process mediated by the filopodia emission from the trypanosome surface. The observed RBC alterations are caused by mechanical and biochemical damage from host-parasite interactions occurring in the bloodstream. The altered erythrocytes are prone to mononuclear phagocytic removal contributing to the hematocrit decrease during infection.

Susceptibility of human Plasmodium knowlesi infections to anti-malarials

PubMed Central

2013-01-01

Background Evidence suggests that Plasmodium knowlesi malaria in Sarawak, Malaysian Borneo remains zoonotic, meaning anti-malarial drug resistance is unlikely to have developed in the absence of drug selection pressure. Therefore, adequate response to available anti-malarial treatments is assumed. Methods Here the ex vivo sensitivity of human P. knowlesi isolates in Malaysian Borneo were studied, using a WHO schizont maturation assay modified to accommodate the quotidian life cycle of this parasite. The in vitro sensitivities of P. knowlesi H strain adapted from a primate infection to in vitro culture (by measuring the production of Plasmodium lactate dehydrogenase) were also examined together with some assays using Plasmodium falciparum and Plasmodium vivax. Results Plasmodium knowlesi is uniformly highly sensitive to artemisinins, variably and moderately sensitive to chloroquine, and less sensitive to mefloquine. Conclusions Taken together with reports of clinical failures when P. knowlesi is treated with mefloquine, the data suggest that caution is required if using mefloquine in prevention or treatment of P. knowlesi infections, until further studies are undertaken. PMID:24245918

Plasmodium spp. in raptors on the Eurasian-African migration route.

PubMed

Paperna, I; Yosef, R; Landau, I

2007-12-01

Examination of blood smears obtained from raptors trapped while on migration at Eilat, Israel, demonstrated Plasmodium infection in Accipiter brevipes and Buteo buteo. The following species are described, from A. brevipes: Plasmodium alloelongatum n. sp., P. accipiteris n. sp. and from B. buteo: P. buteonis n. sp. and Plasmodium sp. for which we lack sufficient data for adequate species description. Overall prevalence of infection with Plasmodium spp. was very low: among 38 examined A. brevipes 5% and among 56 B. buteo 3.6%.

Effect of nutrient deficiencies on in vitro Th1 and Th2 cytokine response of peripheral blood mononuclear cells to Plasmodium falciparum infection

PubMed Central

2010-01-01

Background An appropriate balance between pro-inflammatory and anti-inflammatory cytokines that mediate innate and adaptive immune responses is required for effective protection against human malaria and to avoid immunopathology. In malaria endemic countries, this immunological balance may be influenced by micronutrient deficiencies. Methods Peripheral blood mononuclear cells from Tanzanian preschool children were stimulated in vitro with Plasmodium falciparum-parasitized red blood cells to determine T-cell responses to malaria under different conditions of nutrient deficiencies and malaria status. Results The data obtained indicate that zinc deficiency is associated with an increase in TNF response by 37%; 95% CI: 14% to 118% and IFN-γ response by 74%; 95% CI: 24% to 297%. Magnesium deficiency, on the other hand, was associated with an increase in production of IL-13 by 80%; 95% CI: 31% to 371% and a reduction in IFN-γ production. These results reflect a shift in cytokine profile to a more type I cytokine profile and cell-cell mediated responses in zinc deficiency and a type II response in magnesium deficiency. The data also reveal a non-specific decrease in cytokine production in children due to iron deficiency anaemia that is largely associated with malaria infection status. Conclusions The pathological sequels of malaria potentially depend more on the balance between type I and type II cytokine responses than on absolute suppression of these cytokines and this balance may be influenced by a combination of micronutrient deficiencies and malaria status. PMID:20546583

Resistance to malaria through structural variation of red blood cell invasion receptors.

PubMed

Leffler, Ellen M; Band, Gavin; Busby, George B J; Kivinen, Katja; Le, Quang Si; Clarke, Geraldine M; Bojang, Kalifa A; Conway, David J; Jallow, Muminatou; Sisay-Joof, Fatoumatta; Bougouma, Edith C; Mangano, Valentina D; Modiano, David; Sirima, Sodiomon B; Achidi, Eric; Apinjoh, Tobias O; Marsh, Kevin; Ndila, Carolyne M; Peshu, Norbert; Williams, Thomas N; Drakeley, Chris; Manjurano, Alphaxard; Reyburn, Hugh; Riley, Eleanor; Kachala, David; Molyneux, Malcolm; Nyirongo, Vysaul; Taylor, Terrie; Thornton, Nicole; Tilley, Louise; Grimsley, Shane; Drury, Eleanor; Stalker, Jim; Cornelius, Victoria; Hubbart, Christina; Jeffreys, Anna E; Rowlands, Kate; Rockett, Kirk A; Spencer, Chris C A; Kwiatkowski, Dominic P

2017-06-16

The malaria parasite Plasmodium falciparum invades human red blood cells by a series of interactions between host and parasite surface proteins. By analyzing genome sequence data from human populations, including 1269 individuals from sub-Saharan Africa, we identify a diverse array of large copy-number variants affecting the host invasion receptor genes GYPA and GYPB We find that a nearby association with severe malaria is explained by a complex structural rearrangement involving the loss of GYPB and gain of two GYPB-A hybrid genes, which encode a serologically distinct blood group antigen known as Dantu. This variant reduces the risk of severe malaria by 40% and has recently increased in frequency in parts of Kenya, yet it appears to be absent from west Africa. These findings link structural variation of red blood cell invasion receptors with natural resistance to severe malaria. Copyright © 2017, American Association for the Advancement of Science.

The detection of cryptic Plasmodium infection among villagers in Attapeu province, Lao PDR

PubMed Central

Khattignavong, Phonepadith; Soundala, Pheovaly; Lorphachan, Lavy; Matsumoto-Takahashi, Emilie; Strobel, Michel; Reinharz, Daniel; Phommasansack, Manisack; Hongvanthong, Bouasy; Brey, Paul T.

2017-01-01

Background Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. Methodology/Principal findings A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. Conclusions/Significance There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant

The detection of cryptic Plasmodium infection among villagers in Attapeu province, Lao PDR.

PubMed

Iwagami, Moritoshi; Keomalaphet, Sengdeuane; Khattignavong, Phonepadith; Soundala, Pheovaly; Lorphachan, Lavy; Matsumoto-Takahashi, Emilie; Strobel, Michel; Reinharz, Daniel; Phommasansack, Manisack; Hongvanthong, Bouasy; Brey, Paul T; Kano, Shigeyuki

2017-12-01

Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant species, accounted for 87.2% of the Plasmodium infections among the

Specific antibody responses against membrane proteins of erythrocytes infected by Plasmodium falciparum of individuals briefly exposed to malaria

PubMed Central

2010-01-01

Background Plasmodium falciparum infections could lead to severe malaria, principally in non-immune individuals as children and travellers from countries exempted of malaria. Severe malaria is often associated with the sequestration of P. falciparum-infected erythrocytes in deep micro-vascular beds via interactions between host endothelial receptors and parasite ligands expressed on the surface of the infected erythrocyte. Although, serological responses from individuals living in endemic areas against proteins expressed at surface of the infected erythrocyte have been largely studied, seldom data are available about the specific targets of antibody response from travellers. Methods In order to characterize antigens recognized by traveller sera, a comparison of IgG immune response against membrane protein extracts from uninfected and P. falciparum-infected red blood cells (iRBC), using immunoblots, was performed between non exposed individuals (n = 31) and briefly exposed individuals (BEI) (n = 38) to malaria transmission. Results Immune profile analysis indicated that eight protein bands from iRBC were significantly detected more frequently in the BEI group. Some of these antigenic proteins were identified by an original immuno-proteomic approach. Conclusion Collectively, these data may be useful to characterize the singular serological immune response against a primary malaria infection in individuals briefly exposed to transmission. PMID:20932351

Prolonged Plasmodium falciparum Infection in Immigrants, Paris

PubMed Central

Godineau, Nadine; Fontanet, Arnaud; Houze, Sandrine; Bouchaud, Olivier; Matheron, Sophie; Le Bras, Jacques

2008-01-01

Few immigrant travelers have Plasmodium falciparum infections >2 months after leaving malaria-endemic areas. We conducted a case–control study to identify factors associated with prolonged P. falciparum infection in immigrant travelers. Results suggest that P. falciparum infection should be systematically suspected, even months after travel, especially in pregnant women and first-arrival immigrants. PMID:18258132

Human Infections with Plasmodium knowlesi, the Philippines

PubMed Central

Espino, Fe; Curameng, Peter; Espina, Ronald; Bell, David; Chiodini, Peter; Nolder, Debbie; Sutherland, Colin; Lee, Kim-Sung; Singh, Balbir

2008-01-01

Five human cases of infection with the simian malaria parasite Plasmodium knowlesi from Palawan, the Philippines, were confirmed by nested PCR. This study suggests that this zoonotic infection is found across a relatively wide area in Palawan and documents autochthonous cases in the country. PMID:18439369

Prevalence of malaria parasites (Plasmodium floridense and Plasmodium azurophilum) infecting a Puerto Rican lizard (Anolis gundlachi): a nine-year study.

PubMed

Schall, J J; Pearson, A R; Perkins, S L

2000-06-01

The prevalence of malaria parasites was studied in the lizard Anolis gundlachi over a 9-yr period at a site in the wet evergreen forest of eastern Puerto Rico. Three forms of the parasite infected the lizards; these were Plasmodium floridense, Plasmodium azurophilum in erythrocytes, and P. azurophilum in white blood cells. Overall prevalence of infection for 8 samples during the study period was significantly higher for males than females (32% of 3,296 males and 22% of 1,439 females). During the study, the site experienced substantial climatic and physical disturbance including rising temperature, droughts, and hurricanes that severely damaged the forest. Parasite prevalence in the first sample, 8 mo after the massive hurricane Hugo, was slightly, though significantly, lower than for subsequent samples. However, overall prevalence was stable during the 9-yr period. The results show malaria prevalence is more constant at the site than found for 2 studies in temperate forests, and that the Puerto Rico system may be an example of the stable, endemic malaria described by standard models for human malaria epidemiology.

Protection, pathogenesis and phenotypic plasticity in Plasmodium falciparum malaria.

PubMed

Roberts, D J; Biggs, B A; Brown, G; Newbold, C I

1993-08-01

Why does Plasmodium falciparum cause severe illness in some but not all infections? How is clinical immunity acquired? These questions have intrigued investigators since the clinical epidemiology of malaria was first described. The search for answers to both questions has highlighted the changes that take place at the surface of infected red blood cells during the last half of the erythrocytic cycle. These changes specify the antigenic and adhesive or cytoadherence phenotypes for the infected cell. Now the antigenic and adhesive phenotypes appear to be linked and together undergo clonal variation. In this article David Roberts, Beverley-Ann Biggs, Graham Brown and Christopher Newbold explain how clonal phenotypic variation and the linkage between adhesive and antigenic types contribute to our understanding of naturally acquired immunity and of pathogenesis of severe malaria.

Preserved dendritic cell HLA-DR expression and reduced regulatory T cell activation in asymptomatic Plasmodium falciparum and P. vivax infection.

PubMed

Kho, Steven; Marfurt, Jutta; Noviyanti, Rintis; Kusuma, Andreas; Piera, Kim A; Burdam, Faustina H; Kenangalem, Enny; Lampah, Daniel A; Engwerda, Christian R; Poespoprodjo, Jeanne R; Price, Ric N; Anstey, Nicholas M; Minigo, Gabriela; Woodberry, Tonia

2015-08-01

Clinical illness with Plasmodium falciparum or Plasmodium vivax compromises the function of dendritic cells (DC) and expands regulatory T (Treg) cells. Individuals with asymptomatic parasitemia have clinical immunity, restricting parasite expansion and preventing clinical disease. The role of DC and Treg cells during asymptomatic Plasmodium infection is unclear. During a cross-sectional household survey in Papua, Indonesia, we examined the number and activation of blood plasmacytoid DC (pDC), CD141(+), and CD1c(+) myeloid DC (mDC) subsets and Treg cells using flow cytometry in 168 afebrile children (of whom 15 had P. falciparum and 36 had P. vivax infections) and 162 afebrile adults (of whom 20 had P. falciparum and 20 had P. vivax infections), alongside samples from 16 patients hospitalized with uncomplicated malaria. Unlike DC from malaria patients, DC from children and adults with asymptomatic, microscopy-positive P. vivax or P. falciparum infection increased or retained HLA-DR expression. Treg cells in asymptomatic adults and children exhibited reduced activation, suggesting increased immune responsiveness. The pDC and mDC subsets varied according to clinical immunity (asymptomatic or symptomatic Plasmodium infection) and, in asymptomatic infection, according to host age and parasite species. In conclusion, active control of asymptomatic infection was associated with and likely contingent upon functional DC and reduced Treg cell activation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Antibody-independent mechanisms regulate the establishment of chronic Plasmodium infection

PubMed Central

Lin, Jingwen; Cunningham, Deirdre; Tumwine, Irene; Kushinga, Garikai; McLaughlin, Sarah; Spence, Philip; Böhme, Ulrike; Sanders, Mandy; Conteh, Solomon; Bushell, Ellen; Metcalf, Tom; Billker, Oliver; Duffy, Patrick E.; Newbold, Chris; Berriman, Matthew; Langhorne, Jean

2017-01-01

Malaria is caused by parasites of the genus Plasmodium. All human-infecting Plasmodium species can establish long-lasting chronic infections1–5, creating an infectious reservoir to sustain transmission1,6. It is widely accepted that maintenance of chronic infection involves evasion of adaptive immunity by antigenic variation7. However, genes involved in this process have been identified in only two of five human-infecting species: P. falciparum and P. knowlesi. Furthermore, little is understood about the early events in establishment of chronic infection in these species. Using a rodent model we demonstrate that only a minority of parasites from among the infecting population, expressing one of several clusters of virulence-associated pir genes, establishes a chronic infection. This process occurs in different species of parasite and in different hosts. Establishment of chronicity is independent of adaptive immunity and therefore different from the mechanism proposed for maintainance of chronic P. falciparum infections7–9. Furthermore, we show that the proportions of parasites expressing different types of pir genes regulate the time taken to establish a chronic infection. Since pir genes are common to most, if not all, species of Plasmodium10, this process may be a common way of regulating the establishment of chronic infections. PMID:28165471

Prevalence of PCR detectable malaria infection among febrile patients with a negative Plasmodium falciparum specific rapid diagnostic test in Zanzibar.

PubMed

Baltzell, Kimberly A; Shakely, Deler; Hsiang, Michelle; Kemere, Jordan; Ali, Abdullah Suleiman; Björkman, Anders; Mårtensson, Andreas; Omar, Rahila; Elfving, Kristina; Msellem, Mwinyi; Aydin-Schmidt, Berit; Rosenthal, Philip J; Greenhouse, Bryan

2013-02-01

We screened for malaria in 594 blood samples from febrile patients who tested negative by a Plasmodium falciparum-specific histidine-rich protein-2-based rapid diagnostic test at 12 health facilities in Zanzibar districts North A and Micheweni, from May to August 2010. Screening was with microscopy, polymerase chain reaction (PCR) targeting the cytochrome b gene (cytbPCR) of the four major human malaria species, and quantitative PCR (qPCR). The prevalence of cytbPCR-detectable malaria infection was 2% (12 of 594), including 8 P. falciparum, 3 Plasmodium malariae, and 1 Plasmodium vivax infections. Microscopy identified 4 of 8 P. falciparum infections. Parasite density as estimated by microscopy or qPCR was > 4,000 parasites/μL in 5 of 8 cytbPCR-detectable P. falciparum infections. The infections that were missed by the rapid diagnostic test represent a particular challenge in malaria elimination settings and highlight the need for more sensitive point-of-care diagnostic tools to improve case detection of all human malaria species in febrile patients.

Human Infections and Detection of Plasmodium knowlesi

PubMed Central

Daneshvar, Cyrus

2013-01-01

SUMMARY Plasmodium knowlesi is a malaria parasite that is found in nature in long-tailed and pig-tailed macaques. Naturally acquired human infections were thought to be extremely rare until a large focus of human infections was reported in 2004 in Sarawak, Malaysian Borneo. Human infections have since been described throughout Southeast Asia, and P. knowlesi is now recognized as the fifth species of Plasmodium causing malaria in humans. The molecular, entomological, and epidemiological data indicate that human infections with P. knowlesi are not newly emergent and that knowlesi malaria is primarily a zoonosis. Human infections were undiagnosed until molecular detection methods that could distinguish P. knowlesi from the morphologically similar human malaria parasite P. malariae became available. P. knowlesi infections cause a spectrum of disease and are potentially fatal, but if detected early enough, infections in humans are readily treatable. In this review on knowlesi malaria, we describe the early studies on P. knowlesi and focus on the epidemiology, diagnosis, clinical aspects, and treatment of knowlesi malaria. We also discuss the gaps in our knowledge and the challenges that lie ahead in studying the epidemiology and pathogenesis of knowlesi malaria and in the prevention and control of this zoonotic infection. PMID:23554413

Extremely low Plasmodium prevalence in wild plovers and coursers from Cape Verde and Madagascar.

PubMed

Martínez-de la Puente, Josué; Eberhart-Phillips, Luke J; Cristina Carmona-Isunza, M; Zefania, Sama; Navarro, María José; Kruger, Oliver; Hoffman, Joseph Ivan; Székely, Tamás; Figuerola, Jordi

2017-06-08

Relatively little is known about the prevalence of blood parasites in shorebirds, especially those breeding in the tropics. The prevalence of blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon was assessed in blood samples from Kentish plovers and cream-coloured coursers in Cape Verde, and samples of Kittlitz's plovers, Madagascar plovers and white-fronted plovers in Madagascar. Only two of these samples were positive for Plasmodium: a Kittlitz's plover was infected by a generalist lineage of Plasmodium that has already been reported in Europe and Africa, while in a white-fronted plover direct sequencing revealed a previously un-described Plasmodium lineage. Potential explanations for the low prevalence of blood parasites include the scarcity of vectors in habitats used by these bird species and their resistance to parasitic infections.

Hyperreactive malarial splenomegaly is associated with low levels of antibodies against red blood cell and Plasmodium falciparum derived glycolipids in Yanomami Amerindians from Venezuela.

PubMed

Vivas, Livia; O'Dea, Kieran P; Noya, Oscar; Pabon, Rosalba; Magris, Magda; Botto, Carlos; Holder, Anthony A; Brown, K Neil

2008-03-01

The immunological basis of the aberrant immune response in hyperreactive malarial splenomegaly (HMS) is poorly understood, but believed to be associated with polyclonal B cell activation by an unidentified malaria mitogen, leading to unregulated immunoglobulin and autoantibody production. HMS has been previously reported in Yanomami communities in the Upper Orinoco region of the Venezuelan Amazon. To investigate a possible association between antibody responses against Plasmodium falciparum and uninfected red blood cell (URBC) glycolipids and splenomegaly, a direct comparison of the parasite versus host anti-glycolipid antibody responses was made in an isolated community of this area. The anti-P. falciparum glycolipid (Pfglp) response was IgG3 dominated, whereas the uninfected red blood cell glycolipid (URBCglp) response showed a predominance of IgG1. The levels of IgG1 against Pfglp, and of IgG4 and IgM against URBCglp were significantly higher in women, while the anti-Pfglp or URBCglp IgM levels were inversely correlated with the degree of splenomegaly. Overall, these results suggest differential regulation of anti-parasite and autoreactive responses and that these responses may be linked to the development and evolution of HMS in this population exposed to endemic malaria. The high mortality rates associated with HMS point out that its early diagnosis together with the implementation of malaria control measures in these isolated Amerindian communities are a priority.

Motility and infectivity of Plasmodium berghei sporozoites expressing avian Plasmodium gallinaceum circumsporozoite protein.

PubMed

Tewari, Rita; Rathore, Dharmendar; Crisanti, Andrea

2005-05-01

Avian and rodent malaria sporozoites selectively invade different vertebrate cell types, namely macrophages and hepatocytes, and develop in distantly related vector species. To investigate the role of the circumsporozoite (CS) protein in determining parasite survival in different vector species and vertebrate host cell types, we replaced the endogenous CS protein gene of the rodent malaria parasite Plasmodium berghei with that of the avian parasite P. gallinaceum and control rodent parasite P. yoelii. In anopheline mosquitoes, P. berghei parasites carrying P. gallinaceum and rodent parasite P. yoelii CS protein gene developed into oocysts and sporozoites. Plasmodium gallinaceum CS expressing transgenic sporozoites, although motile, failed to invade mosquito salivary glands and to infect mice, which suggests that motility alone is not sufficient for invasion. Notably, a percentage of infected Anopheles stephensi mosquitoes showed melanotic encapsulation of late stage oocysts. This was not observed in control infections or in A. gambiae infections. These findings shed new light on the role of the CS protein in the interaction of the parasite with both the mosquito vector and the rodent host.

Real-time PCR detection of Plasmodium directly from whole blood and filter paper samples

PubMed Central

2011-01-01

Background Real-time PCR is a sensitive and specific method for the analysis of Plasmodium DNA. However, prior purification of genomic DNA from blood is necessary since PCR inhibitors and quenching of fluorophores from blood prevent efficient amplification and detection of PCR products. Methods Reagents designed to specifically overcome PCR inhibition and quenching of fluorescence were evaluated for real-time PCR amplification of Plasmodium DNA directly from blood. Whole blood from clinical samples and dried blood spots collected in the field in Colombia were tested. Results Amplification and fluorescence detection by real-time PCR were optimal with 40× SYBR® Green dye and 5% blood volume in the PCR reaction. Plasmodium DNA was detected directly from both whole blood and dried blood spots from clinical samples. The sensitivity and specificity ranged from 93-100% compared with PCR performed on purified Plasmodium DNA. Conclusions The methodology described facilitates high-throughput testing of blood samples collected in the field by fluorescence-based real-time PCR. This method can be applied to a broad range of clinical studies with the advantages of immediate sample testing, lower experimental costs and time-savings. PMID:21851640

Parasite-induced ER stress response in hepatocytes facilitates Plasmodium liver stage infection.

PubMed

Inácio, Patricia; Zuzarte-Luís, Vanessa; Ruivo, Margarida T G; Falkard, Brie; Nagaraj, Nagarjuna; Rooijers, Koos; Mann, Matthias; Mair, Gunnar; Fidock, David A; Mota, Maria M

2015-08-01

Upon infection of a mammalian host, Plasmodium parasites first replicate inside hepatocytes, generating thousands of new parasites. Although Plasmodium intra-hepatic development represents a substantial metabolic challenge to the host hepatocyte, how infected cells respond to and integrate this stress remains poorly understood. Here, we present proteomic and transcriptomic analyses, revealing that the endoplasmic reticulum (ER)-resident unfolded protein response (UPR) is activated in host hepatocytes upon Plasmodium berghei infection. The expression of XBP1s--the active form of the UPR mediator XBP1--and the liver-specific UPR mediator CREBH is induced by P. berghei infection in vivo. Furthermore, this UPR induction increases parasite liver burden. Altogether, our data suggest that ER stress is a central feature of P. berghei intra-hepatic development, contributing to the success of infection. © 2015 The Authors.

Multigenomic Delineation of Plasmodium Species of the Laverania Subgenus Infecting Wild-Living Chimpanzees and Gorillas.

PubMed

Liu, Weimin; Sundararaman, Sesh A; Loy, Dorothy E; Learn, Gerald H; Li, Yingying; Plenderleith, Lindsey J; Ndjango, Jean-Bosco N; Speede, Sheri; Atencia, Rebeca; Cox, Debby; Shaw, George M; Ayouba, Ahidjo; Peeters, Martine; Rayner, Julian C; Hahn, Beatrice H; Sharp, Paul M

2016-07-02

Plasmodium falciparum, the major cause of malaria morbidity and mortality worldwide, is only distantly related to other human malaria parasites and has thus been placed in a separate subgenus, termed Laverania Parasites morphologically similar to P. falciparum have been identified in African apes, but only one other Laverania species, Plasmodium reichenowi from chimpanzees, has been formally described. Although recent studies have pointed to the existence of additional Laverania species, their precise number and host associations remain uncertain, primarily because of limited sampling and a paucity of parasite sequences other than from mitochondrial DNA. To address this, we used limiting dilution polymerase chain reaction to amplify additional parasite sequences from a large number of chimpanzee and gorilla blood and fecal samples collected at two sanctuaries and 30 field sites across equatorial Africa. Phylogenetic analyses of more than 2,000 new sequences derived from the mitochondrial, nuclear, and apicoplast genomes revealed six divergent and well-supported clades within the Laverania parasite group. Although two of these clades exhibited deep subdivisions in phylogenies estimated from organelle gene sequences, these sublineages were geographically defined and not present in trees from four unlinked nuclear loci. This greatly expanded sequence data set thus confirms six, and not seven or more, ape Laverania species, of which P. reichenowi, Plasmodium gaboni, and Plasmodium billcollinsi only infect chimpanzees, whereas Plasmodium praefalciparum, Plasmodium adleri, and Pladmodium blacklocki only infect gorillas. The new sequence data also confirm the P. praefalciparum origin of human P. falciparum. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Plasmodium vivax aldolase-specific monoclonal antibodies and its application in clinical diagnosis of malaria infections in China.

PubMed

Dzakah, Emmanuel E; Kang, Keren; Ni, Chao; Wang, Hong; Wu, Peidian; Tang, Shixing; Wang, Jihua; Wang, Jufang; Wang, Xiaoning

2013-06-12

Most rapid diagnostic tests (RDTs) currently used for malaria diagnosis cannot distinguish the various Plasmodium infections. The development of a Plasmodium vivax specific RDTs with high sensitivity to sufficiently differentiate the two most common Plasmodium infections would be very crucial for disease treatment and control. Plasmodium vivax aldolase gene (PvALDO) was amplified from the extracted genomic DNA and constructed into pET30a vector. Plasmodium vivax aldolase protein was successfully expressed in Escherichia coli in soluble form and the overall purity was over 95% after one-step affinity chromatography purification. The purified products were used for the immunization of mice and rabbits. Rabbit polyclonal antibodies generated were deployed to develop a novel antibody-capture ELISA for hybridoma screening. Three PvALDO specific mAbs (14C7, 15F1 and 5H7) with high affinities were selected and used in immunochromatographic test strips. Clinical blood samples (n=190) collected from Yunnan (China) were used for evaluation and the RDT's sensitivity for P. vivax was 98.33% (95% Confidence Interval (CI): 91.03% to 99.72%) compared with microscopic examination. There was specificity of 99.23% (95% CI: 95.77% to 99.87%) for P. vivax. Only one Plasmodium falciparum sample was detected among the P. falciparum samples (n=20). All Plasmodium malariae samples (n=2) as well as healthy uninfected samples (n=108) were negative. Overall performance of this RDT was excellent with positive predictive value (PPV) and negative predictive value (NPV) of 98.33% and 99.23%, respectively, at 95% CI and a very good correlation with microscopic observations (kappa value, K=0.9757). Test strips show high sensitivity even at 6.25 ng/ml of recombinant P. vivax aldolase (rPvALDO). This study further elucidates the possibility of developing aldolase-specific RDTs which can differentiate the different Plasmodium infections and improve accurate diagnosis of malaria. This RDT could

Plasmodium vivax aldolase-specific monoclonal antibodies and its application in clinical diagnosis of malaria infections in China

PubMed Central

2013-01-01

Background Most rapid diagnostic tests (RDTs) currently used for malaria diagnosis cannot distinguish the various Plasmodium infections. The development of a Plasmodium vivax specific RDTs with high sensitivity to sufficiently differentiate the two most common Plasmodium infections would be very crucial for disease treatment and control. Method Plasmodium vivax aldolase gene (PvALDO) was amplified from the extracted genomic DNA and constructed into pET30a vector. Plasmodium vivax aldolase protein was successfully expressed in Escherichia coli in soluble form and the overall purity was over 95% after one-step affinity chromatography purification. The purified products were used for the immunization of mice and rabbits. Rabbit polyclonal antibodies generated were deployed to develop a novel antibody-capture ELISA for hybridoma screening. Results Three PvALDO specific mAbs (14C7, 15F1 and 5H7) with high affinities were selected and used in immunochromatographic test strips. Clinical blood samples (n=190) collected from Yunnan (China) were used for evaluation and the RDT’s sensitivity for P. vivax was 98.33% (95% Confidence Interval (CI): 91.03% to 99.72%) compared with microscopic examination. There was specificity of 99.23% (95% CI: 95.77% to 99.87%) for P. vivax. Only one Plasmodium falciparum sample was detected among the P. falciparum samples (n=20). All Plasmodium malariae samples (n=2) as well as healthy uninfected samples (n=108) were negative. Overall performance of this RDT was excellent with positive predictive value (PPV) and negative predictive value (NPV) of 98.33% and 99.23%, respectively, at 95% CI and a very good correlation with microscopic observations (kappa value, K=0.9757). Test strips show high sensitivity even at 6.25 ng/ml of recombinant P. vivax aldolase (rPvALDO). Conclusion This study further elucidates the possibility of developing aldolase-specific RDTs which can differentiate the different Plasmodium infections and improve accurate

Plasmodium infection, anaemia and mosquito net use among school children across different settings in Kenya.

PubMed

Gitonga, Caroline W; Edwards, Tansy; Karanja, Peris N; Noor, Abdisalan M; Snow, Robert W; Brooker, Simon J

2012-07-01

To investigate risk factors, including reported net use, for Plasmodium infection and anaemia among school children and to explore variations in effects across different malaria ecologies occurring in Kenya. This study analysed data for 49 975 school children in 480 schools surveyed during a national school malaria survey, 2008-2010. Mixed effects logistic regression was used to investigate factors associated with Plasmodium infection and anaemia within different malaria transmission zones. Insecticide-treated net (ITN) use was associated with reduction in the odds of Plasmodium infection in coastal and western highlands epidemic zones and among boys in the lakeside high transmission zone. Other risk factors for Plasmodium infection and for anaemia also varied by zone. Plasmodium infection was negatively associated with increasing socio-economic status in all transmission settings, except in the semi-arid north-east zone. Plasmodium infection was a risk factor for anaemia in lakeside high transmission, western highlands epidemic and central low-risk zones, whereas ITN use was only associated with lower levels of anaemia in coastal and central zones and among boys in the lakeside high transmission zone. The risk factors for Plasmodium infection and anaemia, including the protective associations with ITN use, vary according to malaria transmission settings in Kenya, and future efforts to control malaria and anaemia should take into account such heterogeneities among school children. © 2012 Blackwell Publishing Ltd.

A nested real-time PCR assay for the quantification of Plasmodium falciparum DNA extracted from dried blood spots.

PubMed

Tran, Tuan M; Aghili, Amirali; Li, Shanping; Ongoiba, Aissata; Kayentao, Kassoum; Doumbo, Safiatou; Traore, Boubacar; Crompton, Peter D

2014-10-04

As public health efforts seek to eradicate malaria, there has been an emphasis on eliminating low-density parasite reservoirs in asymptomatic carriers. As such, diagnosing submicroscopic Plasmodium infections using PCR-based techniques has become important not only in clinical trials of malaria vaccines and therapeutics, but also in active malaria surveillance campaigns. However, PCR-based quantitative assays that rely on nucleic acid extracted from dried blood spots (DBS) have demonstrated lower sensitivity than assays that use cryopreserved whole blood as source material. The density of Plasmodium falciparum asexual parasites was quantified using genomic DNA extracted from dried blood spots (DBS) and the sensitivity of two approaches was compared: quantitative real-time PCR (qPCR) targeting the P. falciparum 18S ribosomal RNA gene, either with an initial conventional PCR amplification prior to qPCR (nested qPCR), or without an initial amplification (qPCR only). Parasite densities determined by nested qPCR, qPCR only, and light microscopy were compared. Nested qPCR results in 10-fold higher sensitivity (0.5 parasites/μl) when compared to qPCR only (five parasites/ul). Among microscopy-positive samples, parasite densities calculated by nested qPCR correlated strongly with microscopy for both asymptomatic (Pearson's r=0.58, P<0.001) and symptomatic (Pearson's r=0.70, P<0.0001) P. falciparum infections. Nested qPCR improves the sensitivity for the detection of P. falciparum blood-stage infection from clinical DBS samples. This approach may be useful for active malaria surveillance in areas where submicroscopic asymptomatic infections are prevalent.

Parasite-induced ER stress response in hepatocytes facilitates Plasmodium liver stage infection

PubMed Central

Inácio, Patricia; Zuzarte-Luís, Vanessa; Ruivo, Margarida TG; Falkard, Brie; Nagaraj, Nagarjuna; Rooijers, Koos; Mann, Matthias; Mair, Gunnar; Fidock, David A; Mota, Maria M

2015-01-01

Upon infection of a mammalian host, Plasmodium parasites first replicate inside hepatocytes, generating thousands of new parasites. Although Plasmodium intra-hepatic development represents a substantial metabolic challenge to the host hepatocyte, how infected cells respond to and integrate this stress remains poorly understood. Here, we present proteomic and transcriptomic analyses, revealing that the endoplasmic reticulum (ER)-resident unfolded protein response (UPR) is activated in host hepatocytes upon Plasmodium berghei infection. The expression of XBP1s—the active form of the UPR mediator XBP1—and the liver-specific UPR mediator CREBH is induced by P. berghei infection in vivo. Furthermore, this UPR induction increases parasite liver burden. Altogether, our data suggest that ER stress is a central feature of P. berghei intra-hepatic development, contributing to the success of infection. PMID:26113366

Plasmodium species differentiation by non-expert on-line volunteers for remote malaria field diagnosis.

PubMed

Ortiz-Ruiz, Alejandra; Postigo, María; Gil-Casanova, Sara; Cuadrado, Daniel; Bautista, José M; Rubio, José Miguel; Luengo-Oroz, Miguel; Linares, María

2018-01-30

Routine field diagnosis of malaria is a considerable challenge in rural and low resources endemic areas mainly due to lack of personnel, training and sample processing capacity. In addition, differential diagnosis of Plasmodium species has a high level of misdiagnosis. Real time remote microscopical diagnosis through on-line crowdsourcing platforms could be converted into an agile network to support diagnosis-based treatment and malaria control in low resources areas. This study explores whether accurate Plasmodium species identification-a critical step during the diagnosis protocol in order to choose the appropriate medication-is possible through the information provided by non-trained on-line volunteers. 88 volunteers have performed a series of questionnaires over 110 images to differentiate species (Plasmodium falciparum, Plasmodium ovale, Plasmodium vivax, Plasmodium malariae, Plasmodium knowlesi) and parasite staging from thin blood smear images digitalized with a smartphone camera adapted to the ocular of a conventional light microscope. Visual cues evaluated in the surveys include texture and colour, parasite shape and red blood size. On-line volunteers are able to discriminate Plasmodium species (P. falciparum, P. malariae, P. vivax, P. ovale, P. knowlesi) and stages in thin-blood smears according to visual cues observed on digitalized images of parasitized red blood cells. Friendly textual descriptions of the visual cues and specialized malaria terminology is key for volunteers learning and efficiency. On-line volunteers with short-training are able to differentiate malaria parasite species and parasite stages from digitalized thin smears based on simple visual cues (shape, size, texture and colour). While the accuracy of a single on-line expert is far from perfect, a single parasite classification obtained by combining the opinions of multiple on-line volunteers over the same smear, could improve accuracy and reliability of Plasmodium species

Minocycline prevents cerebral malaria, confers neuroprotection and increases survivability of mice during Plasmodium berghei ANKA infection.

PubMed

Apoorv, Thittayil Suresh; Babu, Phanithi Prakash

2017-02-01

Cerebral malaria (CM) is a neurological complication arising due to Plasmodium falciparum or Plasmodium vivax infection. Minocycline, a semi-synthetic tetracycline, has been earlier reported to have a neuroprotective role in several neurodegenerative diseases. In this study, we investigated the effect of minocycline treatment on the survivability of mice during experimental cerebral malaria (ECM). The currently accepted mouse model, C57BL/6 mice infected with Plasmodium berghei ANKA, was used for the study. Infected mice were treated with an intra-peritoneal dose of minocycline hydrochloride, 45mg/kg daily for ten days that led to parasite clearance in blood, brain, liver and spleen on 7th day post-infection; and the mice survived until experiment ended (90days) without parasite recrudescence. Evans blue extravasation assay showed that blood-brain barrier integrity was maintained by minocycline. The tumor necrosis factor-alpha protein level and caspase activity, which is related to CM pathogenesis, was significantly reduced in the minocycline-treated group. Fluoro-Jade® C and hematoxylin-eosin staining of the brains of minocycline group revealed a decrease in degenerating neurons and absence of hemorrhages respectively. Minocycline treatment led to decrease in gene expressions of inflammatory mediators like interferon-gamma, CXCL10, CCL5, CCL2; receptors CXCR3 and CCR2; and hence decrease in T-cell-mediated cerebral inflammation. We also proved that this reduction in gene expressions is irrespective of the anti-parasitic property of minocycline. The distinct ability of minocycline to modulate gene expressions of CXCL10 and CXCR3 makes it effective than doxycycline, a tetracycline used as chemoprophylaxis. Our study shows that minocycline is highly effective in conferring neuroprotection during ECM. Copyright © 2016 Elsevier Ltd. All rights reserved.

Targeting Angiotensin II Type-1 Receptor (AT1R) Inhibits the Harmful Phenotype of Plasmodium-Specific CD8+ T Cells during Blood-Stage Malaria.

PubMed

Silva-Filho, João L; Caruso-Neves, Celso; Pinheiro, Ana A S

2017-01-01

CD8 + T-cell response is critical in the pathogenesis of cerebral malaria during blood-stage. Our group and other have been shown that angiotensin II (Ang II) and its receptor AT 1 (AT 1 R), a key effector axis of renin-angiotensin system (RAS), have immune regulatory effects on T cells. Previously, we showed that inhibition of AT 1 R signaling protects mice against the lethal disease induced by Plasmodium berghei ANKA infection However, most of the Ang II/AT 1 R actions were characterized by using only pharmacological approaches, the effects of which may not always be due to a specific receptor blockade. In addition, the mechanisms of action of the AT 1 R in inducing the pathogenic activity of Plasmodium -specific CD8 + T cells during blood-stage were not determined. Here, we examined how angiotensin II/AT 1 R axis promotes the harmful response of Plasmodium -specific CD8 + T-cell during blood-stage by using genetic and pharmacological approaches. We evaluated the response of wild-type (WT) and AT 1 R -/- Plasmodium -specific CD8 + T cells in mice infected with a transgenic PbA lineage expressing ovalbumin; and in parallel infected mice receiving WT Plasmodium -specific CD8 + T cells were treated with losartan (AT 1 R antagonist) or captopril (ACE inhibitor). Both, AT 1 R -/- OT-I cells and WT OT-I cells from losartan- or captopril-treated mice showed lower expansion, reduced IL-2 production and IL-2Rα expression, lower activation (lower expression of CD69, CD44 and CD160) and lower exhaustion profiles. AT 1 R -/- OT-I cells also exhibit lower expression of the integrin LFA-1 and the chemokine receptors CCR5 and CXCR3, known to play a key role in the development of cerebral malaria. Moreover, AT 1 R -/- OT-I cells produce lower amounts of IFN-γ and TNF-α and show lower degranulation upon restimulation. In conclusion, our results show the pivotal mechanisms of AT 1 R-induced harmful phenotype of Plasmodium -specific CD8 + T cells during blood-stage malaria.

Multiplicity of Infection and Disease Severity in Plasmodium vivax

PubMed Central

Pacheco, M. Andreína; Lopez-Perez, Mary; Vallejo, Andrés F.; Herrera, Sócrates; Arévalo-Herrera, Myriam; Escalante, Ananias A.

2016-01-01

Background Multiplicity of infection (MOI) refers to the average number of distinct parasite genotypes concurrently infecting a patient. Although several studies have reported on MOI and the frequency of multiclonal infections in Plasmodium falciparum, there is limited data on Plasmodium vivax. Here, MOI and the frequency of multiclonal infections were studied in areas from South America where P. vivax and P. falciparum can be compared. Methodology/Principal Findings As part of a passive surveillance study, 1,328 positive malaria patients were recruited between 2011 and 2013 in low transmission areas from Colombia. Of those, there were only 38 P. vivax and 24 P. falciparum clinically complicated cases scattered throughout the time of the study. Samples from uncomplicated cases were matched in time and location with the complicated cases in order to compare the circulating genotypes for these two categories. A total of 92 P. vivax and 57 P. falciparum uncomplicated cases were randomly subsampled. All samples were genotyped by using neutral microsatellites. Plasmodium vivax showed more multiclonal infections (47.7%) than P. falciparum (14.8%). Population genetics and haplotype network analyses did not detect differences in the circulating genotypes between complicated and uncomplicated cases in each parasite. However, a Fisher exact test yielded a significant association between having multiclonal P. vivax infections and complicated malaria. No association was found for P. falciparum infections. Conclusion The association between multiclonal infections and disease severity in P. vivax is consistent with previous observations made in rodent malaria. The contrasting pattern between P. vivax and P. falciparum could be explained, at least in part, by the fact that P. vivax infections have lineages that were more distantly related among them than in the case of the P. falciparum multiclonal infections. Future research should address the possible role that acquired

Prolonged storage of packed red blood cells for blood transfusion.

PubMed

Martí-Carvajal, Arturo J; Simancas-Racines, Daniel; Peña-González, Barbra S

2015-07-14

('prolonged' or 'older') versus packed red blood cells with < 21 days storage ('fresh'). We pooled data to assess the effect of prolonged storage on death from any cause. The confidence in the results from these trials was very low, due to the bias in their design and their limited sample sizes.The estimated effect of packed red blood cells with ≥ 21 days storage versus packed red blood cells with < 21 days storage for the outcome death from any cause was imprecise (5/45 [11.11%] versus 2/46 [4.34%]; RR 2.36; 95% CI 0.65 to 8.52; I(2): 0%, P = 0.26, very low quality of evidence). Trial sequential analysis, with only two trials, shows that we do not yet have convincing evidence that older packed red blood cells induce a 20% relative risk reduction of death from any cause compared with fresher packed red blood cells. No trial included other outcomes of interest specified in this review, namely transfusion-related acute lung injury, postoperative infections, and adverse events. The safety profile is unknown. Recognising the limitations of the review, relating to the size and nature of the included trials, this Cochrane Review provides no evidence to support or reject the use of packed red blood cells for blood transfusion which have been stored for ≥ 21 days ('prolonged' or 'older') compared with those stored for < 21 days ('fresh'). These results are based on three small single centre trials with high risks of bias. There is insufficient evidence to determine the effects of fresh or older packed red blood cells for blood transfusion. Therefore, we urge readers to interpret the trial results with caution. The results from four large ongoing trials will help to inform future updates of this review.

Global Epidemiology of Plasmodium vivax

PubMed Central

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

2016-01-01

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

Design of microfluidic channels for magnetic separation of malaria-infected red blood cells

PubMed Central

Wu, Wei-Tao; Martin, Andrea Blue; Gandini, Alberto; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F.

2016-01-01

This study is motivated by the development of a blood cell filtration device for removal of malaria-infected, parasitized red blood cells (pRBCs). The blood was modeled as a multi-component fluid using the computational fluid dynamics discrete element method (CFD-DEM), wherein plasma was treated as a Newtonian fluid and the red blood cells (RBCs) were modeled as soft-sphere solid particles which move under the influence of drag, collisions with other RBCs, and a magnetic force. The CFD-DEM model was first validated by a comparison with experimental data from Han et al. 2006 (Han and Frazier 2006) involving a microfluidic magnetophoretic separator for paramagnetic deoxygenated blood cells. The computational model was then applied to a parametric study of a parallel-plate separator having hematocrit of 40% with a 10% of the RBCs as pRBCs. Specifically, we investigated the hypothesis of introducing an upstream constriction to the channel to divert the magnetic cells within the near-wall layer where the magnetic force is greatest. Simulations compared the efficacy of various geometries upon the stratification efficiency of the pRBCs. For a channel with nominal height of 100 µm, the addition of an upstream constriction of 80% improved the proportion of pRBCs retained adjacent to the magnetic wall (separation efficiency) by almost 2 fold, from 26% to 49%. Further addition of a downstream diffuser reduced remixing, hence improved separation efficiency to 72%. The constriction introduced a greater pressure drop (from 17 to 495 Pa), which should be considered when scaling-up this design for a clinical-sized system. Overall, the advantages of this design include its ability to accommodate physiological hematocrit and high throughput – which is critical for clinical implementation as a blood-filtration system. PMID:27761107

Red blood cell production

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... body's tissues in exchange for carbon dioxide, which is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow ... 2 days. The body makes about two million red blood cells every second. Blood is made up of both cellular and liquid components. ...

Quantification of the fraction poorly deformable red blood cells using ektacytometry.

PubMed

Streekstra, G J; Dobbe, J G G; Hoekstra, A G

2010-06-21

We describe a method to obtain the fraction of poorly deformable red blood cells in a blood sample from the intensity pattern in an ektacytometer. In an ektacytometer red blood cells are transformed into ellipsoids by a shear flow between two transparent cylinders. The intensity pattern, due to a laser beam that is sent through the suspension, is projected on a screen. When measuring a healthy red blood cell population iso-intensity curves are ellipses with an axial ratio equal to that of the average red blood cell. In contrast poorly deformable cells result in circular iso-intensity curves. In this study we show that for mixtures of deformable and poorly deformable red blood cells, iso-intensity curves in the composite intensity pattern are neither elliptical nor circular but obtain cross-like shapes. We propose a method to obtain the fraction of poorly deformable red blood cells from those intensity patterns. Experiments with mixtures of poorly deformable and deformable red blood cells validate the method and demonstrate its accuracy. In a clinical setting our approach is potentially of great value for the detection of the fraction of sickle cells in blood samples of patients with sickle cell disease or to find a measure for the parasitemia in patients infected with malaria.

Biomarkers of Plasmodium falciparum Infection during Pregnancy in Women Living in Northeastern Tanzania

PubMed Central

Boström, Stéphanie; Ibitokou, Samad; Oesterholt, Mayke; Schmiegelow, Christentze; Persson, Jan-Olov; Minja, Daniel; Lusingu, John; Lemnge, Martha; Fievet, Nadine; Deloron, Philippe; Luty, Adrian J. F.; Troye-Blomberg, Marita

2012-01-01

In pregnant women, Plasmodium falciparum infections are an important cause of maternal morbidity as well as fetal and neonatal mortality. Erythrocytes infected by these malaria-causing parasites accumulate through adhesive interactions in placental intervillous spaces, thus evading detection in peripheral blood smears. Sequestered infected erythrocytes induce inflammation, offering the possibility of detecting inflammatory mediators in peripheral blood that could act as biomarkers of placental infection. In a longitudinal, prospective study in Tanzania, we quantified a range of different cytokines, chemokines and angiogenic factors in peripheral plasma samples, taken on multiple sequential occasions during pregnancy up to and including delivery, from P. falciparum-infected women and matched uninfected controls. The results show that during healthy, uninfected pregnancies the levels of most of the panel of molecules we measured were largely unchanged except at delivery. In women with P. falciparum, however, both comparative and longitudinal assessments consistently showed that the levels of IL-10 and IP-10 increased significantly whilst that of RANTES decreased significantly, regardless of gestational age at the time the infection was detected. ROC curve analysis indicated that a combination of increased IL-10 and IP-10 levels and decreased RANTES levels might be predictive of P. falciparum infections. In conclusion, our data suggest that host biomarkers in peripheral blood may represent useful diagnostic markers of P. falciparum infection during pregnancy, but placental histology results would need to be included to verify these findings. PMID:23155405

Risk factors for Plasmodium vivax infection in the Lacandon forest, southern Mexico.

PubMed

Danis-Lozano, R; Rodriguez, M H; Gonzalez-Ceron, L; Hernandez-Avila, M

1999-06-01

A study was conducted to characterize the risk of Plasmodium vivax infection in the Lacandon forest, southern Mexico. Blood samples and questionnaire data were collected in 1992. Malaria cases (n = 137) were identified by the presence of symptoms and a positive thick blood smear. The control group included individuals with negative antibody titres and no history of malaria (n = 4994). From 7628 individuals studied, 1006 had anti-P. vivax antibodies. Seroprevalence increased with age. Risk factors associated with infection included: place of birth outside the village of residence (odds ratio, OR 11.67; 95% CI 5.21-26.11); no use of medical services (OR 4.69, 95% CI 3.01-7.29), never using bed-nets (OR 3.98, 95 % CI 1.23-12.86) and poor knowledge of malaria transmission, prevention and treatment (OR 2.30, 95 % CI 1.30-4.07). Health education represents the best recommendation for controlling the disease in the area.

Risk factors for Plasmodium vivax infection in the Lacandon forest, southern Mexico.

PubMed Central

Danis-Lozano, R.; Rodriguez, M. H.; Gonzalez-Ceron, L.; Hernandez-Avila, M.

1999-01-01

A study was conducted to characterize the risk of Plasmodium vivax infection in the Lacandon forest, southern Mexico. Blood samples and questionnaire data were collected in 1992. Malaria cases (n = 137) were identified by the presence of symptoms and a positive thick blood smear. The control group included individuals with negative antibody titres and no history of malaria (n = 4994). From 7628 individuals studied, 1006 had anti-P. vivax antibodies. Seroprevalence increased with age. Risk factors associated with infection included: place of birth outside the village of residence (odds ratio, OR 11.67; 95% CI 5.21-26.11); no use of medical services (OR 4.69, 95% CI 3.01-7.29), never using bed-nets (OR 3.98, 95 % CI 1.23-12.86) and poor knowledge of malaria transmission, prevention and treatment (OR 2.30, 95 % CI 1.30-4.07). Health education represents the best recommendation for controlling the disease in the area. PMID:10459651

Infection of Anopheles aquasalis from symptomatic and asymptomatic Plasmodium vivax infections in Manaus, western Brazilian Amazon.

PubMed

Martins-Campos, Keillen M; Kuehn, Andrea; Almeida, Anne; Duarte, Ana Paula M; Sampaio, Vanderson S; Rodriguez, Íria C; da Silva, Sara G M; Ríos-Velásquez, Claudia María; Lima, José Bento Pereira; Pimenta, Paulo Filemon Paolucci; Bassat, Quique; Müller, Ivo; Lacerda, Marcus; Monteiro, Wuelton M; Barbosa Guerra, Maria das Graças V

2018-05-04

Asymptomatic individuals are one of the major challenges for malaria elimination programs in endemic areas. In the absence of clinical symptoms and with a lower parasite density they constitute silent reservoirs considered important for maintaining transmission of human malaria. Studies from Brazil have shown that infected individuals may carry these parasites for long periods. Patients were selected from three periurban endemic areas of the city of Manaus, in the western Brazilian Amazon. Symptomatic and asymptomatic patients with positive thick blood smear and quantitative real-time PCR (qPCR) positive for Plasmodium vivax were invited to participate in the study. A standardised pvs25 gene amplification by qPCR was used for P. vivax gametocytes detection. Anopheles aquasalis were fed using membrane feeding assays (MFA) containing blood from malaria patients. Parasitemia of 42 symptomatic and 25 asymptomatic individuals was determined by microscopic examination of blood smears and qPCR. Parasitemia density and gametocyte density were assessed as determinants of infection rates and oocysts densities. A strong correlation between gametocyte densities (microscopy and molecular techniques) and mosquito infectivity (P < 0.001) and oocysts median numbers (P < 0.05) was found in both groups. The ability to infect mosquitoes was higher in the symptomatic group (41%), but infectivity in the asymptomatic group was also seen (1.42%). Although their infectivity to mosquitoes is relatively low, given the high prevalence of P. vivax asymptomatic carriers they are likely to play and important role in malaria transmission in the city of Manaus. The role of asymptomatic infections therefore needs to be considered in future malaria elimination programs in Brazil.

Plasmodium falciparum-infected erythrocytes induce Tissue Factor expression in endothelial cells and support the assembly of multimolecular coagulation complexes

PubMed Central

Francischetti, Ivo MB; Seydel, Karl B; Monteiro, Robson Q; Whitten, Richard O; Erexson, Cindy R; Noronha, Almério LL; Ostera, Graciela R.; Kamiza, Steve B; Molyneux, Malcolm E; Ward, Jerrold M; Taylor, Terrie E

2010-01-01

Summary Background Plasmodium falciparum malaria infects 300–500 million people every year causing 1–2 million deaths annually. Evidence of a coagulation disorder, activation of endothelial cells (EC) and increase in inflammatory cytokines are often present in malaria. Objectives We have asked whether parasitized red blood cells (pRBC) interaction with EC induces Tissue Factor expression in vitro and in vivo. The potential of phosphatidylserine-containing pRBC to support the assembly of blood coagulation complexes was also investigated. Results We demonstrate that mature forms of pRBC induce functional expression of tissue factor (TF) by endothelial cells (EC) in vitro with productive assembly of the extrinsic Xnase complex and initiation of the coagulation cascade. Late stage pRBC also support the prothrombinase and intrinsic Xnase complex formation in vitro, and may function as activated platelets in the amplification phase of the blood coagulation. Notably, postmortem brain sections obtained from P. falciparum-infected children who died from Cerebral Malaria and other causes display a consistent staining for TF in the EC. Conclusions These findings place TF expression by endothelium and the amplification of the coagulation cascade by pRBC and/or activated platelets as potentially critical steps in the pathogenesis of malaria. Furthermore, it may allow investigators to test other therapeutic alternatives targeting TF or modulators of EC function in the treatment of malaria and/or its complications. PMID:17002660

Non-invasive surveillance for Plasmodium in reservoir macaque species.

PubMed

Siregar, Josephine E; Faust, Christina L; Murdiyarso, Lydia S; Rosmanah, Lis; Saepuloh, Uus; Dobson, Andrew P; Iskandriati, Diah

2015-10-12

Primates are important reservoirs for human diseases, but their infection status and disease dynamics are difficult to track in the wild. Within the last decade, a macaque malaria, Plasmodium knowlesi, has caused disease in hundreds of humans in Southeast Asia. In order to track cases and understand zoonotic risk, it is imperative to be able to quantify infection status in reservoir macaque species. In this study, protocols for the collection of non-invasive samples and isolation of malaria parasites from naturally infected macaques are optimized. Paired faecal and blood samples from 60 Macaca fascicularis and four Macaca nemestrina were collected. All animals came from Sumatra or Java and were housed in semi-captive breeding colonies around West Java. DNA was extracted from samples using a modified protocol. Nested polymerase chain reactions (PCR) were run to detect Plasmodium using primers targeting mitochondrial DNA. Sensitivity of screening faecal samples for Plasmodium was compared to other studies using Kruskal Wallis tests and logistic regression models. The best primer set was 96.7 % (95 % confidence intervals (CI): 83.3-99.4 %) sensitive for detecting Plasmodium in faecal samples of naturally infected macaques (n = 30). This is the first study to produce definitive estimates of Plasmodium sensitivity and specificity in faecal samples from naturally infected hosts. The sensitivity was significantly higher than some other studies involving wild primates. Faecal samples can be used for detection of malaria infection in field surveys of macaques, even when there are no parasites visible in thin blood smears. Repeating samples from individuals will improve inferences of the epidemiology of malaria in wild primates.

The dangers of accepting a single diagnosis: case report of concurrent Plasmodium knowlesi malaria and dengue infection.

PubMed

Chong, Soon Eu; Mohamad Zaini, Rhendra Hardy; Suraiya, Siti; Lee, Kok Tong; Lim, Jo Anne

2017-01-03

Dengue and malaria are two common, mosquito-borne infections, which may lead to mortality if not managed properly. Concurrent infections of dengue and malaria are rare due to the different habitats of its vectors and activities of different carrier mosquitoes. The first case reported was in 2005. Since then, several concurrent infections have been reported between the dengue virus (DENV) and the malaria protozoans, Plasmodium falciparum and Plasmodium vivax. Symptoms of each infection may be masked by a simultaneous second infection, resulting in late treatment and severe complications. Plasmodium knowlesi is also a common cause of malaria in Malaysia with one of the highest rates of mortality. This report is one of the earliest in literature of concomitant infection between DENV and P. knowlesi in which a delay in diagnosis had placed a patient in a life-threatening situation. A 59-year old man staying near the Belum-Temengor rainforest at the Malaysia-Thailand border was admitted with fever for 6 days, with respiratory distress. His non-structural protein 1 antigen and Anti-DENV Immunoglobulin M tests were positive. He was treated for severe dengue with compensated shock. Treating the dengue had so distracted the clinicians that a blood film for the malaria parasite was not done. Despite aggressive supportive treatment in the intensive care unit (ICU), the patient had unresolved acidosis as well as multi-organ failure involving respiratory, renal, liver, and haematological systems. It was due to the presentation of shivering in the ICU, that a blood film was done on the second day that revealed the presence of P. knowlesi with a parasite count of 520,000/μL. The patient was subsequently treated with artesunate-doxycycline and made a good recovery after nine days in ICU. This case contributes to the body of literature on co-infection between DENV and P. knowlesi and highlights the clinical consequences, which can be severe. Awareness should be raised among

Fiber array based hyperspectral Raman imaging for chemical selective analysis of malaria-infected red blood cells.

PubMed

Brückner, Michael; Becker, Katja; Popp, Jürgen; Frosch, Torsten

2015-09-24

A new setup for Raman spectroscopic wide-field imaging is presented. It combines the advantages of a fiber array based spectral translator with a tailor-made laser illumination system for high-quality Raman chemical imaging of sensitive biological samples. The Gaussian-like intensity distribution of the illuminating laser beam is shaped by a square-core optical multimode fiber to a top-hat profile with very homogeneous intensity distribution to fulfill the conditions of Koehler. The 30 m long optical fiber and an additional vibrator efficiently destroy the polarization and coherence of the illuminating light. This homogeneous, incoherent illumination is an essential prerequisite for stable quantitative imaging of complex biological samples. The fiber array translates the two-dimensional lateral information of the Raman stray light into separated spectral channels with very high contrast. The Raman image can be correlated with a corresponding white light microscopic image of the sample. The new setup enables simultaneous quantification of all Raman spectra across the whole spatial area with very good spectral resolution and thus outperforms other Raman imaging approaches based on scanning and tunable filters. The unique capabilities of the setup for fast, gentle, sensitive, and selective chemical imaging of biological samples were applied for automated hemozoin analysis. A special algorithm was developed to generate Raman images based on the hemozoin distribution in red blood cells without any influence from other Raman scattering. The new imaging setup in combination with the robust algorithm provides a novel, elegant way for chemical selective analysis of the malaria pigment hemozoin in early ring stages of Plasmodium falciparum infected erythrocytes. Copyright © 2015 Elsevier B.V. All rights reserved.

Infection after injury: association with blood transfusion.

PubMed

Rosemurgy, A S; Hart, M B; Murphy, C G; Albrink, M H; Piazza, A; Leparc, G F; Harris, R E

1992-02-01

This study was undertaken to evaluate the association between red blood cell transfusions and infections in an easily stratified, homogenous group of injured adults. All received their initial transfusions upon arrival to the emergency department. Over 5 years, 390 uncross-matched trauma patients received type "O" red blood cells (RBCs) during initial resuscitation. One hundred fifty-four (39%) died within 7 days because of injuries sustained: 236 (61%) survived at least 7 days. Of these 236, clear differences could be seen between those receiving 6 or fewer or 7 or more units of RBCs. When adjusted for age, sex, and severity of injury (Champion Trauma Score, Injury Severity Score, TRISS), the risk of infection was higher in those receiving 7 or more units of RBCs. Similarly, risk of infection was related to units of RBCs transfused in a dose-related fashion. Blood transfusions should be avoided, if possible. Arbitrary "trigger points" for transfusions should be abandoned.

Patterns of mixed Plasmodium species infections among children six years and under in selected malaria hyper-endemic communities of Zambia: population-based survey observations.

PubMed

Sitali, Lungowe; Chipeta, James; Miller, John M; Moonga, Hawela B; Kumar, Nirbhay; Moss, William J; Michelo, Charles

2015-05-02

Although malaria is preventable and treatable, it still claims 660,000 lives every year globally with children under five years of age having the highest burden. In Zambia, malaria rapid diagnostic tests (RDTs) that only detect Plasmodium falciparum are the main confirmatory means for malaria diagnosis in most health facilities without microscopy services. As a consequence of this P. falciparum species diagnostic approach, non-falciparum malaria is not only under-diagnosed but entirely missed, thereby making the exact disease burden unknown. We thus investigated the prevalence of various Plasmodium spp. and associated burden of infection in selected communities in Zambia. Data from two malaria hyper-endemic provinces (Eastern and Luapula) of the 2012 National Malaria Indicator Survey (MIS), conducted between April and May 2012, were used. The MIS is a nationally representative, two-stage cluster survey conducted to coincide with the end of the malaria transmission season. Social, behavioural and background information were collected from households as part of the survey. Thick blood smears, RDTs and dried blood spots (DBS) were collected from children below six years of age. Slides were stained using Giemsa and examined by microscopy while polymerase chain reaction (PCR) was used to analyse the DBS for malaria Plasmodium spp. Multivariate logistic regression was employed to examine the association between background factors and malaria. Overall, 873 children younger than six years of age were surveyed. The overall prevalence of Plasmodium spp. by PCR was 54.3% (95% CI 51-57.6%). Of the total Plasmodium isolates, 88% were P. falciparum, 10.6% were mixed infections and 1.4% were non-falciparum mono infections. Among the mixed infections, the majority were a combination of P. falciparum and P. malariae (6.5% of all mixed infections). Children two years and older (2-5 years) had three-fold higher risk of mixed malaria infections (aOR 2.8 CI 1.31-5.69) than children

Removal of malaria-infected red blood cells using magnetic cell separators: A computational study

PubMed Central

Kim, Jeongho; Massoudi, Mehrdad; Antaki, James F.; Gandini, Alberto

2012-01-01

High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1st –5th order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs. PMID:22345827

A new method for isolation of the intraerythrocytic stages of Plasmodium and Babesia from their host cells.

PubMed

Sobolewski, B; Mackenstedt, U; Mehlhorn, H

1993-01-01

A new method for the isolation of intraerythrocytic stages of Plasmodium berghei and Babesia divergens from red blood cells is described. The technique is based on hydrodynamic forces occurring in a flow channel containing a turbulent liquid current, which are capable of rupturing infected erythrocytes and removing their plasma membrane from the parasites' surface. The temperature and the concentration of cells were revealed as factors influencing the hydrodynamic forces. About 90% of the intact and apparently infectious parasites of both species were isolated from the lysed erythrocytes.

Angiotensin II Moderately Decreases Plasmodium Infection and Experimental Cerebral Malaria in Mice.

PubMed

Gallego-Delgado, Julio; Baravian, Charlotte; Edagha, Innocent; Ty, Maureen C; Ruiz-Ortega, Marta; Xu, Wenyue; Rodriguez, Ana

2015-01-01

Angiotensin II, a peptide hormone that regulates blood pressure, has been proposed as a protective factor against cerebral malaria based on a genetic analysis. In vitro studies have documented an inhibitory effect of angiotensin II on Plasmodium growth, while studies using chemical inhibitors of angiotensin II in mice showed protection against experimental cerebral malaria but not major effects on parasite growth. To determine whether the level of angiotensin II affects Plasmodium growth and/or disease outcome in malaria, elevated levels of angiotensin II were induced in mice by intradermal implantation of osmotic mini-pumps providing constant release of this hormone. Mice were then infected with P. berghei and monitored for parasitemia and incidence of cerebral malaria. Mice infused with angiotensin II showed decreased parasitemia seven days after infection. The development of experimental cerebral malaria was delayed and a moderate increase in survival was observed in mice with elevated angiotensin II, as confirmed by decreased number of cerebral hemorrhages compared to controls. The results presented here show for the first time the effect of elevated levels of angiotensin II in an in vivo model of malaria. The decreased pathogenesis observed in mice complements a previous human genetic study, reinforcing the hypothesis of a beneficial effect of angiotensin II in malaria.

Complete Plasmodium falciparum liver-stage development in liver-chimeric mice.

PubMed

Vaughan, Ashley M; Mikolajczak, Sebastian A; Wilson, Elizabeth M; Grompe, Markus; Kaushansky, Alexis; Camargo, Nelly; Bial, John; Ploss, Alexander; Kappe, Stefan H I

2012-10-01

Plasmodium falciparum, which causes the most lethal form of human malaria, replicates in the host liver during the initial stage of infection. However, in vivo malaria liver-stage (LS) studies in humans are virtually impossible, and in vitro models of LS development do not reconstitute relevant parasite growth conditions. To overcome these obstacles, we have adopted a robust mouse model for the study of P. falciparum LS in vivo: the immunocompromised and fumarylacetoacetate hydrolase-deficient mouse (Fah-/-, Rag2-/-, Il2rg-/-, termed the FRG mouse) engrafted with human hepatocytes (FRG huHep). FRG huHep mice supported vigorous, quantifiable P. falciparum LS development that culminated in complete maturation of LS at approximately 7 days after infection, providing a relevant model for LS development in humans. The infections allowed observations of previously unknown expression of proteins in LS, including P. falciparum translocon of exported proteins 150 (PTEX150) and exported protein-2 (EXP-2), components of a known parasite protein export machinery. LS schizonts exhibited exoerythrocytic merozoite formation and merosome release. Furthermore, FRG mice backcrossed to the NOD background and repopulated with huHeps and human red blood cells supported reproducible transition from LS infection to blood-stage infection. Thus, these mice constitute reliable models to study human LS directly in vivo and demonstrate utility for studies of LS-to-blood-stage transition of a human malaria parasite.

Agglutination Assays of the Plasmodium falciparum-Infected Erythrocyte.

PubMed

Tan, Joshua; Bull, Peter C

2015-01-01

The agglutination assay is used to determine the ability of antibodies to recognize parasite variant antigens on the surface of Plasmodium falciparum-infected erythrocytes. In this technique, infected erythrocytes are selectively labelled with a DNA-binding fluorescent dye and mixed with antibodies of interest to allow antibody-surface antigen binding. Recognition of surface antigens by the antibodies can result in the formation of agglutinates containing multiple parasite-infected erythrocytes. These can be viewed and quantified using a fluorescence microscope.

Limitations of microscopy to differentiate Plasmodium species in a region co-endemic for Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi

PubMed Central

2013-01-01

Background In areas co-endemic for multiple Plasmodium species, correct diagnosis is crucial for appropriate treatment and surveillance. Species misidentification by microscopy has been reported in areas co-endemic for vivax and falciparum malaria, and may be more frequent in regions where Plasmodium knowlesi also commonly occurs. Methods This prospective study in Sabah, Malaysia, evaluated the accuracy of routine district and referral hospital-based microscopy, and microscopy performed by an experienced research microscopist, for the diagnosis of PCR-confirmed Plasmodium falciparum, P. knowlesi, and Plasmodium vivax malaria. Results A total of 304 patients with PCR-confirmed Plasmodium infection were enrolled, including 130 with P. knowlesi, 122 with P. falciparum, 43 with P. vivax, one with Plasmodium malariae and eight with mixed species infections. Among patients with P. knowlesi mono-infection, routine and cross-check microscopy both identified 94 (72%) patients as “P. malariae/P. knowlesi”; 17 (13%) and 28 (22%) respectively were identified as P. falciparum, and 13 (10%) and two (1.5%) as P. vivax. Among patients with PCR-confirmed P. falciparum, routine and cross-check microscopy identified 110/122 (90%) and 112/118 (95%) patients respectively as P. falciparum, and 8/122 (6.6%) and 5/118 (4.2%) as “P. malariae/P. knowlesi”. Among those with P. vivax, 23/43 (53%) and 34/40 (85%) were correctly diagnosed by routine and cross-check microscopy respectively, while 13/43 (30%) and 3/40 (7.5%) patients were diagnosed as “P. malariae/P. knowlesi”. Four of 13 patients with PCR-confirmed P. vivax and misdiagnosed by routine microscopy as “P. malariae/P. knowlesi” were subsequently re-admitted with P. vivax malaria. Conclusions Microscopy does not reliably distinguish between P. falciparum, P. vivax and P. knowlesi in a region where all three species frequently occur. Misdiagnosis of P. knowlesi as both P. vivax and P. falciparum, and vice versa, is

Leukocyte profiles for western fence lizards, Sceloporus occidentalis, naturally infected by the malaria parasite Plasmodium mexicanum.

PubMed

Motz, Victoria L; Lewis, William D; Vardo-Zalik, Anne M

2014-10-01

Plasmodium mexicanum is a malaria parasite that naturally infects the western fence lizard, Sceloporus occidentalis , in northern California. We set out to determine whether lizards naturally infected with this malaria parasite have different leukocyte profiles, indicating an immune response to infection. We used 29 naturally infected western fence lizards paired with uninfected lizards based on sex, snout-to-vent length, tail status, and the presence-absence of ectoparasites such as ticks and mites, as well as the presence-absence of another hemoparasite, Schellackia occidentalis. Complete white blood cell (WBC) counts were conducted on blood smears stained with Giemsa, and the proportion of granulocytes per microliter of blood was estimated using the Avian Leukopet method. The abundance of each WBC class (lymphocytes, monocytes, heterophils, eosinophils, and basophils) in infected and uninfected lizards was compared to determine whether leukocyte densities varied with infection status. We found that the numbers of WBCs and lymphocytes per microliter of blood significantly differed (P < 0.05) between the 2 groups for females but not for males, whereas parasitemia was significantly correlated with lymphocyte counts for males, but not for females. This study supports the theory that infection with P. mexicanum stimulates the lizard's immune response to increase the levels of circulating WBCs, but what effect this has on the biology of the parasite remains unclear.

Natural History of Plasmodium odocoilei Malaria Infection in Farmed White-Tailed Deer.

PubMed

Guggisberg, Ann M; Sayler, Katherine A; Wisely, Samantha M; Odom John, Audrey R

2018-04-25

White-tailed deer ( Odocoileus virginianus ), an ecologically and economically important species, are the most widely distributed large animals in North America. A recent study indicated that up to 25% of all white-tailed deer may be infected with Plasmodium odocoilei , a malaria parasite belonging to the distinct clade of ungulate-infecting Plasmodium spp. Because the clinical impact of P. odocoilei on deer health and survival is unknown, we undertook a retrospective longitudinal study of farmed Floridian O. virginianus fawns. We found that a substantial proportion (21%) of fawns acquire malaria infection during the first 8 months of life. Some animals naturally clear P. odocoilei infection, while other animals remain persistently positive. Importantly, we found that animals that acquire malaria parasites very early in life have poor survival compared to animals that remain uninfected. Our report thus provides the first evidence of a clinically significant impact of malaria infection in young deer. IMPORTANCE Malaria parasites of the genus Plasmodium are known to infect a variety of vertebrate hosts, including ungulates (hoofed mammals). A recent study found that up to a quarter of white-tailed deer ( Odocoileus virginianus ) in North America are infected with the parasite Plasmodium odocoilei In addition to occupying an important ecological niche, white-tailed deer are popular game animals and deer farming represents a rapidly growing industry. However, the effect of P. odocoilei infection in this ecologically and economically important ungulate species is unknown. Our work is significant because (i) we identified a high prevalence of P. odocoilei in farmed deer and (ii) we found evidence for both cleared and persistent infection, as well as an association with decreased survival of young fawns. Copyright © 2018 Guggisberg et al.

High prevalence of very-low Plasmodium falciparum and Plasmodium vivax parasitaemia carriers in the Peruvian Amazon: insights into local and occupational mobility-related transmission.

PubMed

Carrasco-Escobar, Gabriel; Miranda-Alban, Julio; Fernandez-Miñope, Carlos; Brouwer, Kimberly C; Torres, Katherine; Calderon, Maritza; Gamboa, Dionicia; Llanos-Cuentas, Alejandro; Vinetz, Joseph M

2017-10-16

The incidence of malaria due both to Plasmodium falciparum and Plasmodium vivax in the Peruvian Amazon has risen in the past 5 years. This study tested the hypothesis that the maintenance and emergence of malaria in hypoendemic regions such as Amazonia is determined by submicroscopic and asymptomatic Plasmodium parasitaemia carriers. The present study aimed to precisely quantify the rate of very-low parasitaemia carriers in two sites of the Peruvian Amazon in relation to transmission patterns of P. vivax and P. falciparum in this area. This study was carried out within the Amazonian-ICEMR longitudinal cohort. Blood samples were collected for light microscopy diagnosis and packed red blood cell (PRBC) samples were analysed by qPCR. Plasma samples were tested for total IgG reactivity against recombinant PvMSP-10 and PfMSP-10 antigens by ELISA. Occupation and age 10 years and greater were considered surrogates of occupation-related mobility. Risk factors for P. falciparum and P. vivax infections detected by PRBC-qPCR were assessed by multilevel logistic regression models. Among 450 subjects, the prevalence of P. vivax by PRBC-PCR (25.1%) was sixfold higher than that determined by microscopy (3.6%). The prevalence of P. falciparum infection was 4.9% by PRBC-PCR and 0.2% by microscopy. More than 40% of infections had parasitaemia under 5 parasites/μL. Multivariate analysis for infections detected by PRBC-PCR showed that participants with recent settlement in the study area (AOR 2.1; 95% CI 1.03:4.2), age ≥ 30 years (AOR 3.3; 95% CI 1.6:6.9) and seropositivity to P. vivax (AOR 1.8; 95% CI 1.0:3.2) had significantly higher likelihood of P. vivax infection, while the odds of P. falciparum infection was higher for participants between 10 and 29 years (AOR 10.7; 95% CI 1.3:91.1) and with a previous P. falciparum infection (AOR 10.4; 95% CI 1.5:71.1). This study confirms the contrasting transmission patterns of P. vivax and P. falciparum in the Peruvian Amazon, with

In Vitro Alterations Do Not Reflect a Requirement for Host Cell Cycle Progression during Plasmodium Liver Stage Infection

PubMed Central

Hanson, Kirsten K.; March, Sandra; Ng, Shengyong; Bhatia, Sangeeta N.

2014-01-01

Prior to invading nonreplicative erythrocytes, Plasmodium parasites undergo their first obligate step in the mammalian host inside hepatocytes, where each sporozoite replicates to generate thousands of merozoites. While normally quiescent, hepatocytes retain proliferative capacity and can readily reenter the cell cycle in response to diverse stimuli. Many intracellular pathogens, including protozoan parasites, manipulate the cell cycle progression of their host cells for their own benefit, but it is not known whether the hepatocyte cell cycle plays a role during Plasmodium liver stage infection. Here, we show that Plasmodium parasites can be observed in mitotic hepatoma cells throughout liver stage development, where they initially reduce the likelihood of mitosis and ultimately lead to significant acquisition of a binucleate phenotype. However, hepatoma cells pharmacologically arrested in S phase still support robust and complete Plasmodium liver stage development, which thus does not require cell cycle progression in the infected cell in vitro. Furthermore, murine hepatocytes remain quiescent throughout in vivo infection with either Plasmodium berghei or Plasmodium yoelii, as do Plasmodium falciparum-infected primary human hepatocytes, demonstrating that the rapid and prodigious growth of liver stage parasites is accomplished independent of host hepatocyte cell cycle progression during natural infection. PMID:25416236

PCR diagnostics underestimate the prevalence of avian malaria (Plasmodium relictum) in experimentally-infected passerines

USGS Publications Warehouse

Jarvi, Susan I.; Schultz, Jeffrey J.; Atkinson, Carter T.

2002-01-01

Several polymerase chain reaction (PCR)-based methods have recently been developed for diagnosing malarial infections in both birds and reptiles, but a critical evaluation of their sensitivity in experimentally-infected hosts has not been done. This study compares the sensitivity of several PCR-based methods for diagnosing avian malaria (Plasmodium relictum) in captive Hawaiian honeycreepers using microscopy and a recently developed immunoblotting technique. Sequential blood samples were collected over periods of up to 4.4 yr after experimental infection and rechallenge to determine both the duration and detectability of chronic infections. Two new nested PCR approaches for detecting circulating parasites based on P. relictum 18S rRNA genes and the thrombospondin-related anonymous protein (TRAP) gene are described. The blood smear and the PCR tests were less sensitive than serological methods for detecting chronic malarial infections. Individually, none of the diagnostic methods was 100% accurate in detecting subpatent infections, although serological methods were significantly more sensitive (97%) than either nested PCR (61–84%) or microscopy (27%). Circulating parasites in chronically infected birds either disappear completely from circulation or to drop to intensities below detectability by nested PCR. Thus, the use of PCR as a sole means of detection of circulating parasites may significantly underestimate true prevalence.

Infection with Wolbachia protects mosquitoes against Plasmodium-induced mortality in a natural system.

PubMed

Zélé, F; Nicot, A; Duron, O; Rivero, A

2012-07-01

In recent years, there has been a shift in the one host-one parasite paradigm with the realization that, in the field, most hosts are coinfected with multiple parasites. Coinfections are particularly relevant when the host is a vector of diseases, because multiple infections can have drastic consequences for parasite transmission at both the ecological and evolutionary timescales. Wolbachia pipientis is the most common parasitic microorganism in insects, and as such, it is of special interest for understanding the role of coinfections in the outcome of parasite infections. Here, we investigate whether Wolbachia can modulate the effect of Plasmodium on what is, arguably, the most important component of the vectorial capacity of mosquitoes: their longevity. For this purpose, and in contrast to recent studies that have focused on mosquito-Plasmodium and/or mosquito-Wolbachia combinations not found in nature, we work on a Wolbachia-mosquito-Plasmodium triad with a common evolutionary history. Our results show that Wolbachia protects mosquitoes from Plasmodium-induced mortality. The results are consistent across two different strains of Wolbachia and repeatable across two different experimental blocks. To our knowledge, this is the first time that such an effect has been shown for Plasmodium-infected mosquitoes and, in particular, in a natural Wolbachia-host combination. We discuss different mechanistic and evolutionary explanations for these results as well as their consequences for Plasmodium transmission. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Plasmodium berghei EXP-1 interacts with host Apolipoprotein H during Plasmodium liver-stage development

PubMed Central

Sá e Cunha, Cláudia; Nyboer, Britta; Heiss, Kirsten; Sanches-Vaz, Margarida; Fontinha, Diana; Wiedtke, Ellen; Grimm, Dirk; Przyborski, Jude Marek; Mota, Maria M.; Prudêncio, Miguel; Mueller, Ann-Kristin

2017-01-01

The first, obligatory replication phase of malaria parasite infections is characterized by rapid expansion and differentiation of single parasites in liver cells, resulting in the formation and release of thousands of invasive merozoites into the bloodstream. Hepatic Plasmodium development occurs inside a specialized membranous compartment termed the parasitophorous vacuole (PV). Here, we show that, during the parasite’s hepatic replication, the C-terminal region of the parasitic PV membrane protein exported protein 1 (EXP-1) binds to host Apolipoprotein H (ApoH) and that this molecular interaction plays a pivotal role for successful Plasmodium liver-stage development. Expression of a truncated EXP-1 protein, missing the specific ApoH interaction site, or down-regulation of ApoH expression in either hepatic cells or mouse livers by RNA interference resulted in impaired intrahepatic development. Furthermore, infection of mice with sporozoites expressing a truncated version of EXP-1 resulted in both a significant reduction of liver burden and delayed blood-stage patency, leading to a disease outcome different from that generally induced by infection with wild-type parasites. This study identifies a host–parasite protein interaction during the hepatic stage of infection by Plasmodium parasites. The identification of such vital interactions may hold potential toward the development of novel malaria prevention strategies. PMID:28137845

21 CFR 640.10 - Red Blood Cells.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.10 Red Blood Cells. The proper name of this product shall be Red Blood Cells. The product is defined as red blood cells remaining... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Red Blood Cells. 640.10 Section 640.10 Food and...

21 CFR 640.10 - Red Blood Cells.

Code of Federal Regulations, 2013 CFR

2013-04-01

... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.10 Red Blood Cells. The proper name of this product shall be Red Blood Cells. The product is defined as red blood cells remaining... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Red Blood Cells. 640.10 Section 640.10 Food and...

21 CFR 640.10 - Red Blood Cells.

Code of Federal Regulations, 2011 CFR

2011-04-01

... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.10 Red Blood Cells. The proper name of this product shall be Red Blood Cells. The product is defined as red blood cells remaining... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Red Blood Cells. 640.10 Section 640.10 Food and...

21 CFR 640.10 - Red Blood Cells.

Code of Federal Regulations, 2012 CFR

2012-04-01

... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.10 Red Blood Cells. The proper name of this product shall be Red Blood Cells. The product is defined as red blood cells remaining... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Red Blood Cells. 640.10 Section 640.10 Food and...

21 CFR 640.10 - Red Blood Cells.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Red Blood Cells. 640.10 Section 640.10 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.10 Red Blood Cells. The proper name of this product shall be Red Blood Cells. The product is defined as red blood cells remaining...

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.

Infectious pancreatic necrosis virus triggers antiviral immune response in rainbow trout red blood cells, despite not being infective

PubMed Central

Nombela, Ivan; Carrion, Aurora; Puente-Marin, Sara; Chico, Verónica; Mercado, Luis; Perez, Luis; Coll, Julio; Ortega-Villaizan, Maria del Mar

2017-01-01

Background: Some fish viruses, such as piscine orthoreovirus and infectious salmon anemia virus, target red blood cells (RBCs), replicate inside them and induce an immune response. However, the roles of RBCs in the context of infectious pancreatic necrosis virus (IPNV) infection  have not been studied yet. Methods: Ex vivo rainbow trout RBCs were obtained from peripheral blood, Ficoll purified and exposed to IPNV in order to analyze infectivity and immune response using RT-qPCR, immune fluorescence imaging, flow cytometry and western-blotting techniques. Results: IPNV could not infect RBCs; however, IPNV increased the expression of the INF1-related genes ifn-1, pkr and mx genes. Moreover, conditioned media from IPNV-exposed RBCs conferred protection against IPNV infection in CHSE-214 fish cell line. Conclusions: Despite not being infected, rainbow trout RBCs could respond to IPNV with increased expression of antiviral genes. Fish RBCs could be considered as mediators of the antiviral response and therefore targets of new strategies against fish viral infections. Further research is ongoing to completely understand the molecular mechanism that triggers this antiviral response in rainbow trout RBCs. PMID:29333244

Infectious pancreatic necrosis virus triggers antiviral immune response in rainbow trout red blood cells, despite not being infective.

PubMed

Nombela, Ivan; Carrion, Aurora; Puente-Marin, Sara; Chico, Verónica; Mercado, Luis; Perez, Luis; Coll, Julio; Ortega-Villaizan, Maria Del Mar

2017-01-01

Background : Some fish viruses, such as piscine orthoreovirus and infectious salmon anemia virus, target red blood cells (RBCs), replicate inside them and induce an immune response. However, the roles of RBCs in the context of infectious pancreatic necrosis virus (IPNV) infection  have not been studied yet. Methods : Ex vivo rainbow trout RBCs were obtained from peripheral blood, Ficoll purified and exposed to IPNV in order to analyze infectivity and immune response using RT-qPCR, immune fluorescence imaging, flow cytometry and western-blotting techniques. Results : IPNV could not infect RBCs; however, IPNV increased the expression of the INF1-related genes ifn-1 , pkr and mx genes. Moreover, conditioned media from IPNV-exposed RBCs conferred protection against IPNV infection in CHSE-214 fish cell line. Conclusions : Despite not being infected, rainbow trout RBCs could respond to IPNV with increased expression of antiviral genes. Fish RBCs could be considered as mediators of the antiviral response and therefore targets of new strategies against fish viral infections. Further research is ongoing to completely understand the molecular mechanism that triggers this antiviral response in rainbow trout RBCs.

Prevalence of Plasmodium falciparum and non-P. falciparum infections in a highland district in Ghana, and the influence of HIV and sickle cell disease.

PubMed

Owusu, Ewurama D A; Brown, Charles A; Grobusch, Martin P; Mens, Petra

2017-04-24

In the past two decades, there has been a reported decline in malaria in Ghana and the rest of the world; yet it remains the number one cause of mortality and morbidity. Human immuno-deficiency virus (HIV) and sickle cell disease (SCD) share a common geographical space with malaria in sub-Saharan Africa and an interaction between these three conditions has been suggested. This study determined the Plasmodium falciparum and non-P. falciparum status of symptomatic and non-symptomatic residents of Mpraeso in the highlands of Kwahu-South district of Ghana based on evidence of current national decline. The influence of HIV and SCD on malaria was also determined. Participants were 354 symptomatic patients visiting the Kwahu Government Hospital and 360 asymptomatic residents of the district capital. This cross-sectional study was conducted during the minor rainy season (October-December 2014). Rapid diagnostic tests (RDT), blood film microscopy and real-time polymerase chain reaction assessment of blood were done. Participants who tested positive with RDT were treated with artemisinin-based combination therapy; and assessment of venous blood was repeated 7 days after treatment. HIV screening and haemoglobin genotyping was done. Univariate and multivariate regression analysis was used to determine the influence of SCD and HIV. Plasmodium falciparum was prevalent at 124/142 (87.3%). Plasmodium malariae was the only non-falciparum species detected at 18/142 (12.7%). HIV and SCD did not significantly increase odds of malaria infection. However, the use of ITN and recent anti-malarial intake significantly decreased the odds of being malaria infected by 0.45-fold and 0.46-fold respectively. Plasmodium falciparum and P. malariae infection are the prevailing species in the study area; albeit varying from the national average. HIV and SCD were not associated with the risk of having malaria.

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

PubMed

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

2013-05-28

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

ABO blood groups and malaria related clinical outcome.

PubMed

Deepa; Alwar, Vanamala A; Rameshkumar, Karuna; Ross, Cecil

2011-03-01

The study was undertaken to correlate the blood groups and clinical presentations in malaria patients and to understand the differential host susceptibility in malaria. From October 2007 to September 2008, malaria positive patients' samples were evaluated in this study. Hemoglobin, total leukocyte count, and platelet count of each patient were done on an automated cell counter. After determining the blood groups, malarial species and the severity of clinical course were correlated. A total of 100 patients were included in the study, of which 63 cases were positive for Plasmodium falciparum and 37 cases were positive for P. vivax infection and 11 patients had mixed infection. The results of the blood groups showed 22 - 'A' group, 42 - 'B' group, 35 - 'O' group and 1 was 'AB' group. When the clinical courses between different groups were compared using the following parameters for severe infection--a parasitic load of >10/1000 RBCs, severe anemia with hemoglobin < 6 g%, platelet count of <10,000/mm3, hepato or splenomegaly or clinical signs of severe malaria such as fever >101°F and other organ involvement, it was observed that 'O' group had an advantage over other the groups. The difference in rosetting ability between red blood cells of different 'ABO' blood groups with a diminished rosetting potential in blood group 'O' red blood cells was due to the differential host susceptibility. 'O' group had an advantage over the other three blood groups. Based on literature and the results of this study, the diminished rosetting potential in blood group 'O' red blood cells is suggested as the basis for the differential host susceptibility.

Plasmodium cynomolgi infections in rhesus macaques display clinical and parasitological features pertinent to modelling vivax malaria pathology and relapse infections.

PubMed

Joyner, Chester; Moreno, Alberto; Meyer, Esmeralda V S; Cabrera-Mora, Monica; Kissinger, Jessica C; Barnwell, John W; Galinski, Mary R

2016-09-02

Plasmodium vivax infections in humans or in new world monkeys pose research challenges that necessitate the use of alternative model systems. Plasmodium cynomolgi is a closely related species that shares genetic and biological characteristics with P. vivax, including relapses. Here, the haematological dynamics and clinical presentation of sporozoite-initiated P. cynomolgi infections in Macaca mulatta (rhesus macaques) are evaluated over a 100-day period. Five M. mulatta were inoculated with 2000 P. cynomolgi B strain sporozoites. Parasitological and haematological data were collected daily to study the clinical presentations of primary infections and relapses. Peripheral blood and bone marrow aspirates were collected at specific time points during infection for future and retrospective systems biology analyses. Patent infections were observed between days 10 and 12, and the acute, primary infection consisted of parasitaemias ranging from 269,962 to 1,214,842 parasites/µl (4.42-19.5 % parasitaemia). All animals presented with anaemia, ranging from moderate (7-10 g/dl) to severe (<7 g/dl), based on peripheral haemoglobin concentrations. Minimum haemoglobin levels coincided with the clearance of parasites and peripheral reticulocytosis was evident at this time. Mild thrombocytopaenia (<150,000 platelets/µl) was observed in all animals, but unlike haemoglobin, platelets were lowest whenever peripheral parasitaemia peaked. The animals' conditions were classified as non-severe, severe or lethal (in one case) based upon their clinical presentation. The lethal phenotype presented uniquely with an exceptionally high parasitaemia (19.5 %) and lack of a modest reticulocyte release, which was observed in the other animals prior to acute manifestations. One or two relapses were observed in the four surviving animals, and these were characterized by significantly lower parasitaemias and minimal changes in clinical parameters compared to pre-infection values. Rhesus

Plasmodium vivax infection: a major determinant of severe anaemia in infancy.

PubMed

Kenangalem, Enny; Karyana, Muhammad; Burdarm, Lenny; Yeung, Shunmay; Simpson, Julie A; Tjitra, Emiliana; Anstey, Nicholas M; Poespoprodjo, Jeanne Rini; Price, Ric N; Douglas, Nicholas M

2016-06-16

Most malarious countries outside of Africa are co-endemic for Plasmodium falciparum and Plasmodium vivax. The comparative burden of anaemia in the community caused by these two species is incompletely characterized. A three-stage, cross-sectional, community survey was used to determine the proportion of moderate or severe anaemia (haemoglobin <7 g/dL) attributable to patent P. vivax, P. falciparum and mixed parasitaemia in Papua, Indonesia. Adjusted population-attributable fractions were calculated from multivariable logistic regression models. Eight hundred and twenty-five households were surveyed with a total of 5255 occupants, 3890 (74 %) of whom were present and provided a blood sample. Plasmodium falciparum parasitaemia was present in 8.1 % (n = 315) of participants, P. vivax in 6.4 % (n = 250) and mixed infections in 1.9 % (n = 72). Overall, P. falciparum was associated with a mean reduction in haemoglobin of 1.16 g/dL compared to those without patent parasitaemia [95 % confidence interval (95 % CI) 0.91, 1.41 g/dL]. The corresponding values for P. vivax and mixed infections were 0.66 g/dL (95 % CI 0.35, 0.96) and 1.25 g/dL (0.71, 1.80), respectively. Overall, 16.7 % (95 % CI 8.52, 24.2 %) of haemoglobin concentrations <7 g/dL in the community were estimated to be attributable to patent parasitaemia. The fractions for infants and 1-5 years old were 34.4 % (95 % CI -3.30, 58.3 %) and 23.2 % (95 % CI 3.34, 39.0 %), respectively. Plasmodium vivax was associated with a greater than threefold higher attributable fraction of anaemia in infants compared with P. falciparum [27.6 % (95 % CI -3.20, 49.2 %) versus 7.94 % (-5.87, 20.0 %)]. Despite comparatively low-level endemicity, malaria is associated with a significant proportion of all cases of community anaemia in southern Papua. Contrary to its benign reputation, P. vivax is an important and preventable risk factor for anaemia during infancy-a probable consequence of relapsing

Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells

PubMed Central

Mairbäurl, Heimo

2013-01-01

During exercise the cardiovascular system has to warrant substrate supply to working muscle. The main function of red blood cells in exercise is the transport of O2 from the lungs to the tissues and the delivery of metabolically produced CO2 to the lungs for expiration. Hemoglobin also contributes to the blood's buffering capacity, and ATP and NO release from red blood cells contributes to vasodilation and improved blood flow to working muscle. These functions require adequate amounts of red blood cells in circulation. Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called “sports anemia.” This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals. The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV). The mechanisms that increase total red blood cell mass by training are not understood fully. Despite stimulated erythropoiesis, exercise can decrease the red blood cell mass by intravascular hemolysis mainly of senescent red blood cells, which is caused by mechanical rupture when red blood cells pass through capillaries in contracting muscles, and by compression of red cells e.g., in foot soles during running or in hand palms in weightlifters. Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes. These younger red cells are characterized by improved oxygen release and deformability, both of which also improve tissue oxygen supply during exercise. PMID:24273518

Widespread occurrence of lysine methylation in Plasmodium falciparum proteins at asexual blood stages.

PubMed

Kaur, Inderjeet; Zeeshan, Mohammad; Saini, Ekta; Kaushik, Abhinav; Mohmmed, Asif; Gupta, Dinesh; Malhotra, Pawan

2016-10-20

Post-transcriptional and post-translational modifications play a major role in Plasmodium life cycle regulation. Lysine methylation of histone proteins is well documented in several organisms, however in recent years lysine methylation of proteins outside histone code is emerging out as an important post-translational modification (PTM). In the present study we have performed global analysis of lysine methylation of proteins in asexual blood stages of Plasmodium falciparum development. We immunoprecipitated stage specific Plasmodium lysates using anti-methyl lysine specific antibodies that immunostained the asexual blood stage parasites. Using liquid chromatography and tandem mass spectrometry analysis, 570 lysine methylated proteins at three different blood stages were identified. Analysis of the peptide sequences identified 605 methylated sites within 422 proteins. Functional classification of the methylated proteins revealed that the proteins are mainly involved in nucleotide metabolic processes, chromatin organization, transport, homeostatic processes and protein folding. The motif analysis of the methylated lysine peptides reveals novel motifs. Many of the identified lysine methylated proteins are also interacting partners/substrates of PfSET domain proteins as revealed by STRING database analysis. Our findings suggest that the protein methylation at lysine residues is widespread in Plasmodium and plays an important regulatory role in diverse set of the parasite pathways.

Severe anaemia associated with Plasmodium falciparum infection in children: consequences for additional blood sampling for research.

PubMed

Kuijpers, Laura Maria Francisca; Maltha, Jessica; Guiraud, Issa; Kaboré, Bérenger; Lompo, Palpouguini; Devlieger, Hugo; Van Geet, Chris; Tinto, Halidou; Jacobs, Jan

2016-06-02

Plasmodium falciparum infection may cause severe anaemia, particularly in children. When planning a diagnostic study on children suspected of severe malaria in sub-Saharan Africa, it was questioned how much blood could be safely sampled; intended blood volumes (blood cultures and EDTA blood) were 6 mL (children aged <6 years) and 10 mL (6-12 years). A previous review [Bull World Health Organ. 89: 46-53. 2011] recommended not to exceed 3.8 % of total blood volume (TBV). In a simulation exercise using data of children previously enrolled in a study about severe malaria and bacteraemia in Burkina Faso, the impact of this 3.8 % safety guideline was evaluated. For a total of 666 children aged >2 months to <12 years, data of age, weight and haemoglobin value (Hb) were available. For each child, the estimated TBV (TBVe) (mL) was calculated by multiplying the body weight (kg) by the factor 80 (ml/kg). Next, TBVe was corrected for the degree of anaemia to obtain the functional TBV (TBVf). The correction factor consisted of the rate 'Hb of the child divided by the reference Hb'; both the lowest ('best case') and highest ('worst case') reference Hb values were used. Next, the exact volume that a 3.8 % proportion of this TBVf would present was calculated and this volume was compared to the blood volumes that were intended to be sampled. When applied to the Burkina Faso cohort, the simulation exercise pointed out that in 5.3 % (best case) and 11.4 % (worst case) of children the blood volume intended to be sampled would exceed the volume as defined by the 3.8 % safety guideline. Highest proportions would be in the age groups 2-6 months (19.0 %; worst scenario) and 6 months-2 years (15.7 %; worst case scenario). A positive rapid diagnostic test for P. falciparum was associated with an increased risk of violating the safety guideline in the worst case scenario (p = 0.016). Blood sampling in children for research in P. falciparum endemic settings may easily violate

Biophysical Properties of Plasmodium falciparum-Infected Erythrocytes from Novel Analysis of the Flicker Phenomena

NASA Astrophysics Data System (ADS)

Arie, Takayuki; Jin, Albert; Dvorak, James

2002-03-01

Infectious processes often modulate the intrinsic properties of vertebrate cells. We studied the modulation of human erythrocyte flicker during the intra-erythrocytic cycle of Plasmodium falciparum malaria using video microscopy imaging and a data analysis system of our design to extract flicker spectra and lateral cell edge undulations of individual erythrocytes at various stages of infection. The total flicker power, the power weighted mean flicker frequency, the mode amplitudes of lateral undulations, and the time correlation of translation mode was quantified by infectious stage and modeled theoretically. Our results suggest that malaria-infected erythrocytes become increasingly more rigid following infection and provide an insight into the modulation of erythrocyte cytoplasmic viscosity by the parasites. These studies of malaria-infected erythrocytes elucidate the kinetics of both membrane and cellular changes that are relevant to blood microcirculation and improve our understanding of the malaria disease process.

Photosensitized inactivation of infectious blood-borne human parasites

NASA Astrophysics Data System (ADS)

Judy, Millard M.; Sogandares-Bernal, Franklin M.; Matthews, James Lester

1995-05-01

Blood-borne viruses and protozoan parasites that are infectious to humans pose risk world-wide of infection transmission through blood and blood product transfusion. Blood-borne infectious viruses include human immunodeficiency virus (HIV-I), which causes AIDS; hepatitis C virus, which can cause chronic hepatitis; and cytomegalovirus, which can be dangerous to immunocompromised patients, e.g., the newborn, transplant recipients, and AIDS patients. Infectious blood-borne protozoan parasites include Trypanosoma cruzi, which causes Chagas' disease, endemic throughout Central and South America; the Trypanosoma species causing African sleeping sickness endemic in Central Africa; and Plasmodium falciparum, which causes malignant and increasingly drug- resistant human malaria prevalent throughout the tropics. Some researchers have focused on using photosensitizers to inactivate HIV-I and other viruses in whole blood, packed red cells, and platelet concentrates without compromising blood product function. Our group previously has reported photosensitized in vitro inactivation of P. falciparum and the mouse malaria organism Plasmodium berghei in whole blood using hematoporphyrin derivative (HPD) and of T. cruzi using benzoporphyrin derivatives BPDMA and BPDDA, dihematoporphyrin ether (DHE), and hydroxyethylvinyldeuteroporphyrin (HEVD). These results suggest that continued investigation is warranted to evaluate the potential for photosensitized inactivation of blood-borne parasites in blood banking.

Differential susceptibilities of Anopheles albimanus and Anopheles pseudopunctipennis to infections with coindigenous Plasmodium vivax variants VK210 and VK247 in southern Mexico.

PubMed

Gonzalez-Ceron, L; Rodriguez, M H; Nettel, J C; Villarreal, C; Kain, K C; Hernandez, J E

1999-01-01

The susceptibilities to coindigenous Plasmodium vivax of colonized Anopheles albimanus and Anopheles pseudopunctipennis from southern Mexico were investigated by simultaneous feeding with infected blood obtained from patients. The genes encoding circumsporozoite protein variant types (VK210 and VK247) in blood samples were determined by PCR and oligonucleotide probe hybridization. A. albimanus was more susceptible to VK210, and A. pseudopunctipennis was more susceptible to VK247.

Complete Plasmodium falciparum liver-stage development in liver-chimeric mice

PubMed Central

Vaughan, Ashley M.; Mikolajczak, Sebastian A.; Wilson, Elizabeth M.; Grompe, Markus; Kaushansky, Alexis; Camargo, Nelly; Bial, John; Ploss, Alexander; Kappe, Stefan H.I.

2012-01-01

Plasmodium falciparum, which causes the most lethal form of human malaria, replicates in the host liver during the initial stage of infection. However, in vivo malaria liver-stage (LS) studies in humans are virtually impossible, and in vitro models of LS development do not reconstitute relevant parasite growth conditions. To overcome these obstacles, we have adopted a robust mouse model for the study of P. falciparum LS in vivo: the immunocompromised and fumarylacetoacetate hydrolase–deficient mouse (Fah–/–, Rag2–/–, Il2rg–/–, termed the FRG mouse) engrafted with human hepatocytes (FRG huHep). FRG huHep mice supported vigorous, quantifiable P. falciparum LS development that culminated in complete maturation of LS at approximately 7 days after infection, providing a relevant model for LS development in humans. The infections allowed observations of previously unknown expression of proteins in LS, including P. falciparum translocon of exported proteins 150 (PTEX150) and exported protein-2 (EXP-2), components of a known parasite protein export machinery. LS schizonts exhibited exoerythrocytic merozoite formation and merosome release. Furthermore, FRG mice backcrossed to the NOD background and repopulated with huHeps and human red blood cells supported reproducible transition from LS infection to blood-stage infection. Thus, these mice constitute reliable models to study human LS directly in vivo and demonstrate utility for studies of LS–to–blood-stage transition of a human malaria parasite. PMID:22996664

Effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum infected erythrocytes

PubMed Central

Saiwaew, Somporn; Sritabal, Juntima; Piaraksa, Nattaporn; Keayarsa, Srisuda; Ruengweerayut, Ronnatrai; Utaisin, Chirapong; Sila, Patima; Niramis, Rangsan; Udomsangpetch, Rachanee; Charunwatthana, Prakaykaew; Pongponratn, Emsri; Pukrittayakamee, Sasithon; Leitgeb, Anna M.; Wahlgren, Mats; Lee, Sue J.; Day, Nicholas P. J.; White, Nicholas J.; Dondorp, Arjen M.; Chotivanich, Kesinee

2017-01-01

In severe falciparum malaria cytoadherence of parasitised red blood cells (PRBCs) to vascular endothelium (causing sequestration) and to uninfected red cells (causing rosette formation) contribute to microcirculatory flow obstruction in vital organs. Heparin can reverse the underlying ligand-receptor interactions, but may increase the bleeding risks. As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Sevuparin has been evaluated recently in patients with uncomplicated falciparum malaria, and is currently investigated in a clinical trial for sickle cell disease. The effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum isolates from Thailand were investigated. Trophozoite stages of P. falciparum-infected RBCs (Pf-iRBCs) were cultured from 49 patients with malaria. Pf-iRBCs were treated with sevuparin at 37°C and assessed in rosetting and in cytoadhesion assays with human dermal microvascular endothelial cells (HDMECs) under static and flow conditions. The proportion of Pf-iRBCs forming rosettes ranged from 6.5% to 26.0% (median = 12.2%). Rosetting was dose dependently disrupted by sevuparin (50% disruption by 250 μg/mL). Overall 57% of P. falciparum isolates bound to HDMECs under static conditions; median (interquartile range) Pf-iRBC binding was 8.5 (3.0–38.0) Pf-iRBCs/1000 HDMECs. Sevuparin in concentrations ≥ 100 μg/mL inhibited cytoadherence. Sevuparin disrupts P. falciparum rosette formation in a dose dependent manner and inhibits cytoadherence to endothelial cells. The data support assessment of sevuparin as an adjunctive treatment to the standard therapy in severe falciparum malaria. PMID:28249043

The Rheopathobiology of Plasmodium vivax and Other Important Primate Malaria Parasites.

PubMed

Russell, Bruce M; Cooke, Brian M

2017-04-01

Our current understanding of how malaria parasites remodel their host red blood cells (RBCs) and ultimately cause disease is largely based on studies of Plasmodium falciparum. In this review, we expand our knowledge to include what is currently known about pathophysiological changes to RBCs that are infected by non-falciparum malaria parasites. We highlight the potential folly of making generalizations about the rheology of malaria infection, and emphasize the need for more systematic studies into the erythrocytic biology of non-falciparum malaria parasites. We propose that a better understanding of the mechanisms that underlie the changes to RBCs induced by malaria parasites other than P. falciparum may be highly informative for the development of therapeutics that specifically disrupt the altered rheological profile of RBCs infected with either sexual- or asexual-stage parasites, resulting in drugs that block transmission, reduce disease severity, and help delay the onset of resistance to current and future anti-malaria drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed Central

2013-01-01

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

Positive Selection of Plasmodium falciparum Parasites With Multiple var2csa-Type PfEMP1 Genes During the Course of Infection in Pregnant Women

PubMed Central

Salanti, Ali; Lavstsen, Thomas; Nielsen, Morten A.; Theander, Thor G.; Leke, Rose G. F.; Lo, Yeung Y.; Bobbili, Naveen; Arnot, David E.; Taylor, Diane W.

2011-01-01

Placental malaria infections are caused by Plasmodium falciparum–infected red blood cells sequestering in the placenta by binding to chondroitin sulfate A, mediated by VAR2CSA, a variant of the PfEMP1 family of adhesion antigens. Recent studies have shown that many P. falciparum genomes have multiple genes coding for different VAR2CSA proteins, and parasites with >1 var2csa gene appear to be more common in pregnant women with placental malaria than in nonpregnant individuals. We present evidence that, in pregnant women, parasites containing multiple var2csa-type genes possess a selective advantage over parasites with a single var2csa gene. Accumulation of parasites with multiple copies of the var2csa gene during the course of pregnancy was also correlated with the development of antibodies involved in blocking VAR2CSA adhesion. The data suggest that multiplicity of var2csa-type genes enables P. falciparum parasites to persist for a longer period of time during placental infections, probably because of their greater capacity for antigenic variation and evasion of variant-specific immune responses. PMID:21592998

Circulating red cell-derived microparticles in human malaria.

PubMed

Nantakomol, Duangdao; Dondorp, Arjen M; Krudsood, Srivicha; Udomsangpetch, Rachanee; Pattanapanyasat, Kovit; Combes, Valery; Grau, Georges E; White, Nicholas J; Viriyavejakul, Parnpen; Day, Nicholas P J; Chotivanich, Kesinee

2011-03-01

In patients with falciparum malaria, plasma concentrations of cell-derived microparticles correlate with disease severity. Using flow cytometry, we quantified red blood cell-derived microparticles (RMPs) in patients with malaria and identified the source and the factors associated with production. RMP concentrations were increased in patients with Plasmodium falciparum (n = 29; median, 457 RMPs/μL [range, 13-4,342 RMPs/μL]), Plasmodium vivax (n = 5; median, 409 RMPs/μL [range, 281-503/μL]), and Plasmodium malariae (n = 2; median, 163 RMPs/μL [range, 127-200 RMPs/μL]) compared with those in healthy subjects (n = 11; median, 8 RMPs/μL [range, 3-166 RMPs/μL]; P = .01). RMP concentrations were highest in patients with severe falciparum malaria (P = .01). Parasitized red cells produced >10 times more RMPs than did unparasitized cells, but the overall majority of RMPs still derived from uninfected red blood cells (URBCs). In cultures, RMP production increased as the parasites matured. Hemin and parasite products induced RMP production in URBCs, which was inhibited by N-acetylcysteine, suggesting heme-mediated oxidative stress as a pathway for the generation of RMPs.

Circulating Red Cell–derived Microparticles in Human Malaria

PubMed Central

Nantakomol, Duangdao; Dondorp, Arjen M.; Krudsood, Srivicha; Udomsangpetch, Rachanee; Pattanapanyasat, Kovit; Combes, Valery; Grau, Georges E.; White, Nicholas J.; Viriyavejakul, Parnpen; Day, Nicholas P.J.

2011-01-01

In patients with falciparum malaria, plasma concentrations of cell-derived microparticles correlate with disease severity. Using flow cytometry, we quantified red blood cell–derived microparticles (RMPs) in patients with malaria and identified the source and the factors associated with production. RMP concentrations were increased in patients with Plasmodium falciparum (n = 29; median, 457 RMPs/μL [range, 13–4,342 RMPs/μL]), Plasmodium vivax (n = 5; median, 409 RMPs/μL [range, 281–503/μL]), and Plasmodium malariae (n = 2; median, 163 RMPs/μL [range, 127–200 RMPs/μL]) compared with those in healthy subjects (n = 11; median, 8 RMPs/μL [range, 3–166 RMPs/μL]; P = .01). RMP concentrations were highest in patients with severe falciparum malaria (P = .01). Parasitized red cells produced >10 times more RMPs than did unparasitized cells, but the overall majority of RMPs still derived from uninfected red blood cells (URBCs). In cultures, RMP production increased as the parasites matured. Hemin and parasite products induced RMP production in URBCs, which was inhibited by N-acetylcysteine, suggesting heme-mediated oxidative stress as a pathway for the generation of RMPs. PMID:21282195

A PfRH5-Based Vaccine Is Efficacious against Heterologous Strain Blood-Stage Plasmodium falciparum Infection in Aotus Monkeys

PubMed Central

Douglas, Alexander D.; Baldeviano, G. Christian; Lucas, Carmen M.; Lugo-Roman, Luis A.; Crosnier, Cécile; Bartholdson, S. Josefin; Diouf, Ababacar; Miura, Kazutoyo; Lambert, Lynn E.; Ventocilla, Julio A.; Leiva, Karina P.; Milne, Kathryn H.; Illingworth, Joseph J.; Spencer, Alexandra J.; Hjerrild, Kathryn A.; Alanine, Daniel G.W.; Turner, Alison V.; Moorhead, Jeromy T.; Edgel, Kimberly A.; Wu, Yimin; Long, Carole A.; Wright, Gavin J.; Lescano, Andrés G.; Draper, Simon J.

2015-01-01

Summary Antigenic diversity has posed a critical barrier to vaccine development against the pathogenic blood-stage infection of the human malaria parasite Plasmodium falciparum. To date, only strain-specific protection has been reported by trials of such vaccines in nonhuman primates. We recently showed that P. falciparum reticulocyte binding protein homolog 5 (PfRH5), a merozoite adhesin required for erythrocyte invasion, is highly susceptible to vaccine-inducible strain-transcending parasite-neutralizing antibody. In vivo efficacy of PfRH5-based vaccines has not previously been evaluated. Here, we demonstrate that PfRH5-based vaccines can protect Aotus monkeys against a virulent vaccine-heterologous P. falciparum challenge and show that such protection can be achieved by a human-compatible vaccine formulation. Protection was associated with anti-PfRH5 antibody concentration and in vitro parasite-neutralizing activity, supporting the use of this in vitro assay to predict the in vivo efficacy of future vaccine candidates. These data suggest that PfRH5-based vaccines have potential to achieve strain-transcending efficacy in humans. PMID:25590760

Treatment uptake by individuals infected with Plasmodium falciparum in rural Gambia, West Africa.

PubMed Central

von Seidlein, Lorenz; Clarke, Sian; Alexander, Neâl; Manneh, Fandingding; Doherty, Tom; Pinder, Margaret; Walraven, Gijs; Greenwood, Brian

2002-01-01

OBJECTIVE: To find out what proportion of Plasmodium falciparum infections are treated in rural Gambia. METHODS: Subjects from four villages in the Gambia were followed over nine months through visits to village health workers. Monthly cross-sectional malaria surveys measured the prevalence of P. falciparum infection. Linked databases were searched for treatment requests. Treated cases were individuals with parasitaemia who requested treatment during narrow or extended periods (14 or 28 days, respectively) before or after a positive blood film was obtained. FINDINGS: Parasite prevalence peaked in November 1998, when 399/653 (61%) individuals had parasitaemia. Parasite prevalence was highest throughout the study in children aged 5-10 years. Although access to treatment was better than in most of sub-Saharan Africa, only 20% of infected individuals sought medical treatment up to 14 days before or after a positive blood film. Within two months of a positive blood film, 199/726 (27%) individuals with parasitaemia requested treatment. Despite easy access to health care, less than half (42%) of those with parasite densities consistent with malaria attacks (5000/ l) requested treatment. High parasite density and infection during October-November were associated with more frequent treatment requests. Self-treatment was infrequent in study villages: in 3/120 (2.5%) households antimalarial drugs had been used in the preceding malaria season. CONCLUSION: Many P. falciparum infections may be untreated because of their subclinical nature. Intermittent presumptive treatment may reduce morbidity and mortality. It is likely that not all untreated infections were asymptomatic. Qualitative research should explore barriers to treatment uptake, to allow educational interventions to be planned. PMID:12471399

Differential Susceptibilities of Anopheles albimanus and Anopheles pseudopunctipennis to Infections with Coindigenous Plasmodium vivax Variants VK210 and VK247 in Southern Mexico

PubMed Central

Gonzalez-Ceron, Lilia; Rodriguez, Mario H.; Nettel, Jose C.; Villarreal, Cuauhtemoc; Kain, Kevin C.; Hernandez, Juan E.

1999-01-01

The susceptibilities to coindigenous Plasmodium vivax of colonized Anopheles albimanus and Anopheles pseudopunctipennis from southern Mexico were investigated by simultaneous feeding with infected blood obtained from patients. The genes encoding circumsporozoite protein variant types (VK210 and VK247) in blood samples were determined by PCR and oligonucleotide probe hybridization. A. albimanus was more susceptible to VK210, and A. pseudopunctipennis was more susceptible to VK247. PMID:9864243

Integrated quantitative phase and birefringence microscopy for imaging malaria-infected red blood cells.

PubMed

Li, Chengshuai; Chen, Shichao; Klemba, Michael; Zhu, Yizheng

2016-09-01

A dual-modality birefringence/phase imaging system is presented. The system features a crystal retarder that provides polarization mixing and generates two interferometric carrier waves in a single signal spectrum. The retardation and orientation of sample birefringence can then be measured simultaneously based on spectral multiplexing interferometry. Further, with the addition of a Nomarski prism, the same setup can be used for quantitative differential interference contrast (DIC) imaging. Sample phase can then be obtained with two-dimensional integration. In addition, birefringence-induced phase error can be corrected using the birefringence data. This dual-modality approach is analyzed theoretically with Jones calculus and validated experimentally with malaria-infected red blood cells. The system generates not only corrected DIC and phase images, but a birefringence map that highlights the distribution of hemozoin crystals.

Integrated quantitative phase and birefringence microscopy for imaging malaria-infected red blood cells

NASA Astrophysics Data System (ADS)

Li, Chengshuai; Chen, Shichao; Klemba, Michael; Zhu, Yizheng

2016-09-01

A dual-modality birefringence/phase imaging system is presented. The system features a crystal retarder that provides polarization mixing and generates two interferometric carrier waves in a single signal spectrum. The retardation and orientation of sample birefringence can then be measured simultaneously based on spectral multiplexing interferometry. Further, with the addition of a Nomarski prism, the same setup can be used for quantitative differential interference contrast (DIC) imaging. Sample phase can then be obtained with two-dimensional integration. In addition, birefringence-induced phase error can be corrected using the birefringence data. This dual-modality approach is analyzed theoretically with Jones calculus and validated experimentally with malaria-infected red blood cells. The system generates not only corrected DIC and phase images, but a birefringence map that highlights the distribution of hemozoin crystals.

Interactive cost of Plasmodium infection and insecticide resistance in the malaria vector Anopheles gambiae.

PubMed

Alout, Haoues; Dabiré, Roch K; Djogbénou, Luc S; Abate, Luc; Corbel, Vincent; Chandre, Fabrice; Cohuet, Anna

2016-07-19

Insecticide resistance raises concerns for the control of vector-borne diseases. However, its impact on parasite transmission could be diverse when considering the ecological interactions between vector and parasite. Thus we investigated the fitness cost associated with insecticide resistance and Plasmodium falciparum infection as well as their interactive cost on Anopheles gambiae survival and fecundity. In absence of infection, we observed a cost on fecundity associated with insecticide resistance. However, survival was higher for mosquito bearing the kdr mutation and equal for those with the ace-1(R) mutation compared to their insecticide susceptible counterparts. Interestingly, Plasmodium infection reduced survival only in the insecticide resistant strains but not in the susceptible one and infection was associated with an increase in fecundity independently of the strain considered. This study provides evidence for a survival cost associated with infection by Plasmodium parasite only in mosquito selected for insecticide resistance. This suggests that the selection of insecticide resistance mutation may have disturbed the interaction between parasites and vectors, resulting in increased cost of infection. Considering the fitness cost as well as other ecological aspects of this natural mosquito-parasite combination is important to predict the epidemiological impact of insecticide resistance.

Static and dynamic light scattering of healthy and malaria-parasite invaded red blood cells

NASA Astrophysics Data System (ADS)

Park, Yongkeun; Diez-Silva, Monica; Fu, Dan; Popescu, Gabriel; Choi, Wonshik; Barman, Ishan; Suresh, Subra; Feld, Michael S.

2010-03-01

We present the light scattering of individual Plasmodium falciparum-parasitized human red blood cells (Pf-RBCs), and demonstrate progressive alterations to the scattering signal arising from the development of malaria-inducing parasites. By selectively imaging the electric fields using quantitative phase microscopy and a Fourier transform light scattering technique, we calculate the light scattering maps of individual Pf-RBCs. We show that the onset and progression of pathological states of the Pf-RBCs can be clearly identified by the static scattering maps. Progressive changes to the biophysical properties of the Pf-RBC membrane are captured from dynamic light scattering.

The NHLBI Retrovirus Epidemiology Donor Studies (REDS and REDS-II): Twenty years of research to advance blood product safety and availability

PubMed Central

Kleinman, Steven; King, Melissa R; Busch, Michael P; Murphy, Edward L; Glynn, Simone A.

2012-01-01

The Retrovirus Epidemiology Donor Study (REDS), conducted from 1989–2001, and the Retrovirus Epidemiology Donor Study-II (REDS-II), conducted from 2004–2012, were National Heart Lung and Blood Institute (NHLBI) funded multicenter programs focused on improving blood safety and availability in the United States. REDS-II also included international study sites in Brazil and China. The three major research domains of REDS/REDS-II have been infectious disease risk evaluation, blood donation availability, and blood donor characterization. Both programs have made significant contributions to transfusion medicine research methodology by the use of mathematical modeling, large-scale donor surveys, innovative methods of repository sample storage, and establishing an infrastructure that responded to potential emerging blood safety threats such as XMRV. Blood safety studies have included protocols evaluating epidemiologic and/or laboratory aspects of HIV, HTLV I/II, HCV, HBV, WNV, CMV, HHV-8, B19V, malaria, CJD, influenza, and T. cruzi infections. Other analyses have characterized: blood donor demographics, motivations to donate, factors influencing donor return, behavioral risk factors, donors’ perception of the blood donation screening process, and aspects of donor deferral. In REDS-II, two large-scale blood donor protocols examined iron deficiency in donors and the prevalence of leukocyte antibodies. This review describes the major study results from over 150 peer-reviewed articles published by these two REDS programs. In 2011, a new seven year program, the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III), was launched. REDS-III expands beyond donor-based research to include studies of blood transfusion recipients in the hospital setting, and adds a third country, South Africa, to the international program. PMID:22633182

The Relative Contribution of Symptomatic and Asymptomatic Plasmodium vivax and Plasmodium falciparum Infections to the Infectious Reservoir in a Low-Endemic Setting in Ethiopia.

PubMed

Tadesse, Fitsum G; Slater, Hannah C; Chali, Wakweya; Teelen, Karina; Lanke, Kjerstin; Belachew, Mulualem; Menberu, Temesgen; Shumie, Girma; Shitaye, Getasew; Okell, Lucy C; Graumans, Wouter; van Gemert, Geert-Jan; Kedir, Soriya; Tesfaye, Addisu; Belachew, Feleke; Abebe, Wake; Mamo, Hassen; Sauerwein, Robert; Balcha, Taye; Aseffa, Abraham; Yewhalaw, Delenasaw; Gadisa, Endalamaw; Drakeley, Chris; Bousema, Teun

2018-06-01

The majority of Plasmodium vivax and Plasmodium falciparum infections in low-endemic settings are asymptomatic. The relative contribution to the infectious reservoir of these infections compared to clinical malaria cases is currently unknown. We assessed infectivity of passively recruited symptomatic malaria patients (n = 41) and community-recruited asymptomatic individuals with microscopy-detected (n = 41) and polymerase chain reaction (PCR)-detected infections (n = 82) using membrane feeding assays with Anopheles arabiensis mosquitoes in Adama, Ethiopia. Malaria incidence and prevalence data were used to estimate the contributions of these populations to the infectious reservoir. Overall, 34.9% (29/83) of P. vivax- and 15.1% (8/53) P. falciparum-infected individuals infected ≥1 mosquitoes. Mosquito infection rates were strongly correlated with asexual parasite density for P. vivax (ρ = 0.63; P < .001) but not for P. falciparum (ρ = 0.06; P = .770). Plasmodium vivax symptomatic infections were more infectious to mosquitoes (infecting 46.5% of mosquitoes, 307/660) compared to asymptomatic microscopy-detected (infecting 12.0% of mosquitoes, 80/667; P = .005) and PCR-detected infections (infecting 0.8% of mosquitoes, 6/744; P < .001). Adjusting for population prevalence, symptomatic, asymptomatic microscopy-detected, and PCR-detected infections were responsible for 8.0%, 76.2%, and 15.8% of the infectious reservoir for P. vivax, respectively. For P. falciparum, mosquito infections were sparser and also predominantly from asymptomatic infections. In this low-endemic setting aiming for malaria elimination, asymptomatic infections were highly prevalent and responsible for the majority of onward mosquito infections. The early identification and treatment of asymptomatic infections might accelerate elimination efforts.

Interactions between Asaia, Plasmodium and Anopheles: new insights into mosquito symbiosis and implications in malaria symbiotic control.

PubMed

Capone, Aida; Ricci, Irene; Damiani, Claudia; Mosca, Michela; Rossi, Paolo; Scuppa, Patrizia; Crotti, Elena; Epis, Sara; Angeletti, Mauro; Valzano, Matteo; Sacchi, Luciano; Bandi, Claudio; Daffonchio, Daniele; Mandrioli, Mauro; Favia, Guido

2013-06-18

Malaria represents one of the most devastating infectious diseases. The lack of an effective vaccine and the emergence of drug resistance make necessary the development of new effective control methods. The recent identification of bacteria of the genus Asaia, associated with larvae and adults of malaria vectors, designates them as suitable candidates for malaria paratransgenic control.To better characterize the interactions between Asaia, Plasmodium and the mosquito immune system we performed an integrated experimental approach. Quantitative PCR analysis of the amount of native Asaia was performed on individual Anopheles stephensi specimens. Mosquito infection was carried out with the strain PbGFPCON and the number of parasites in the midgut was counted by fluorescent microscopy.The colonisation of infected mosquitoes was achieved using GFP or DsRed tagged-Asaia strains.Reverse transcriptase-PCR analysis, growth and phagocytosis tests were performed using An. stephensi and Drosophila melanogaster haemocyte cultures and DsRed tagged-Asaia and Escherichia coli strains. Using quantitative PCR we have quantified the relative amount of Asaia in infected and uninfected mosquitoes, showing that the parasite does not interfere with bacterial blooming. The correlation curves have confirmed the active replication of Asaia, while at the same time, the intense decrease of the parasite.The 'in vitro' immunological studies have shown that Asaia induces the expression of antimicrobial peptides, however, the growth curves in conditioned medium as well as a phagocytosis test, indicated that the bacterium is not an immune-target.Using fluorescent strains of Asaia and Plasmodium we defined their co-localisation in the mosquito midgut and salivary glands. We have provided important information about the relationship of Asaia with both Plasmodium and Anopheles. First, physiological changes in the midgut following an infected or uninfected blood meal do not negatively affect the

The sensing of poorly deformable red blood cells by the human spleen can be mimicked in vitro

PubMed Central

Deplaine, Guillaume; Safeukui, Innocent; Jeddi, Fakhri; Lacoste, François; Brousse, Valentine; Perrot, Sylvie; Biligui, Sylvestre; Guillotte, Micheline; Guitton, Corinne; Dokmak, Safi; Aussilhou, Béatrice; Sauvanet, Alain; Cazals Hatem, Dominique; Paye, François; Thellier, Marc; Mazier, Dominique; Milon, Geneviève; Mohandas, Narla; Mercereau-Puijalon, Odile; David, Peter H.

2011-01-01

Retention of poorly deformable red blood cells (RBCs) by the human spleen has been recognized as a critical determinant of pathogenesis in hereditary spherocytosis, malaria, and other RBC disorders. Using an ex vivo perfusion system, we had previously shown that retention of Plasmodium falciparum–infected RBCs (Pf-RBCs) occur in the splenic red pulp, upstream from the sinus wall. To experimentally replicate the mechanical sensing of RBCs by the splenic microcirculation, we designed a sorting device where a mixture of 5- to 25-μm-diameter microbeads mimics the geometry of narrow and short interendothelial splenic slits. Heated RBCs, Pf-RBCs, and RBCs from patients with hereditary spherocytosis were retained in the microbead layer, without hemolysis. The retention rates of Pf-RBCs were similar in microbeads and in isolated perfused human spleens. These in vitro results directly confirm the importance of the mechanical sensing of RBCs by the human spleen. In addition, rigid and deformable RBC subpopulations could be separated and characterized at the molecular level, and the device was used to deplete a stored RBC population from its subpopulation of rigid RBCs. This experimental approach may contribute to a better understanding of the role of the spleen in the pathogenesis of inherited and acquired RBC disorders. PMID:21163923

Microfluidic cell-phoresis enabling high-throughput analysis of red blood cell deformability and biophysical screening of antimalarial drugs.

PubMed

Santoso, Aline T; Deng, Xiaoyan; Lee, Jeong-Hyun; Matthews, Kerryn; Duffy, Simon P; Islamzada, Emel; McFaul, Sarah M; Myrand-Lapierre, Marie-Eve; Ma, Hongshen

2015-12-07

Changes in red blood cell (RBC) deformability are associated with the pathology of many diseases and could potentially be used to evaluate disease status and treatment efficacy. We developed a simple, sensitive, and multiplexed RBC deformability assay based on the spatial dispersion of single cells in structured microchannels. This mechanism is analogous to gel electrophoresis, but instead of transporting molecules through nano-structured material to measure their length, RBCs are transported through micro-structured material to measure their deformability. After transport, the spatial distribution of cells provides a readout similar to intensity bands in gel electrophoresis, enabling simultaneous measurement on multiple samples. We used this approach to study the biophysical signatures of falciparum malaria, for which we demonstrate label-free and calibration-free detection of ring-stage infection, as well as in vitro assessment of antimalarial drug efficacy. We show that clinical antimalarial drugs universally reduce the deformability of RBCs infected by Plasmodium falciparum and that recently discovered PfATP4 inhibitors, known to induce host-mediated parasite clearance, display a distinct biophysical signature. Our process captures key advantages from gel electrophoresis, including image-based readout and multiplexing, to provide a functional screen for new antimalarials and adjunctive agents.

A Novel Model of Asymptomatic Plasmodium Parasitemia That Recapitulates Elements of the Human Immune Response to Chronic Infection

PubMed Central

Baccarella, Alyssa; Craft, Joshua F.; Boyle, Michelle J.; McIntyre, Tara I.; Wood, Matthew D.; Thorn, Kurt S.; Anidi, Chioma; Bayat, Aqieda; Chung, Me Ree; Hamburger, Rebecca; Kim, Chris Y.; Pearman, Emily; Pham, Jennifer; Tang, Jia J.; Boon, Louis; Kamya, Moses R.; Dorsey, Grant; Feeney, Margaret E.; Kim, Charles C.

2016-01-01

In humans, immunity to Plasmodium sp. generally takes the form of protection from symptomatic malaria (i.e., 'clinical immunity') rather than infection ('sterilizing immunity'). In contrast, mice infected with Plasmodium develop sterilizing immunity, hindering progress in understanding the mechanistic basis of clinical immunity. Here we present a novel model in which mice persistently infected with P. chabaudi exhibit limited clinical symptoms despite sustaining patent parasite burdens for many months. Characterization of immune responses in persistently infected mice revealed development of CD4+ T cell exhaustion, increased production of IL-10, and expansion of B cells with an atypical surface phenotype. Additionally, persistently infected mice displayed a dramatic increase in circulating nonclassical monocytes, a phenomenon that we also observed in humans with both chronic Plasmodium exposure and asymptomatic infection. Following pharmacological clearance of infection, previously persistently infected mice could not control a secondary challenge, indicating that persistent infection disrupts the sterilizing immunity that typically develops in mouse models of acute infection. This study establishes an animal model of asymptomatic, persistent Plasmodium infection that recapitulates several central aspects of the immune response in chronically exposed humans. As such, it provides a novel tool for dissection of immune responses that may prevent development of sterilizing immunity and limit pathology during infection. PMID:27583554

Red Blood Cell Susceptibility to Pneumolysin

PubMed Central

Bokori-Brown, Monika; Petrov, Peter G.; Khafaji, Mawya A.; Mughal, Muhammad K.; Naylor, Claire E.; Shore, Angela C.; Gooding, Kim M.; Casanova, Francesco; Mitchell, Tim J.; Titball, Richard W.; Winlove, C. Peter

2016-01-01

This study investigated the effect of the biochemical and biophysical properties of the plasma membrane as well as membrane morphology on the susceptibility of human red blood cells to the cholesterol-dependent cytolysin pneumolysin, a key virulence factor of Streptococcus pneumoniae, using single cell studies. We show a correlation between the physical properties of the membrane (bending rigidity and surface and dipole electrostatic potentials) and the susceptibility of red blood cells to pneumolysin-induced hemolysis. We demonstrate that biochemical modifications of the membrane induced by oxidative stress, lipid scrambling, and artificial cell aging modulate the cell response to the toxin. We provide evidence that the diversity of response to pneumolysin in diabetic red blood cells correlates with levels of glycated hemoglobin and that the mechanical properties of the red blood cell plasma membrane are altered in diabetes. Finally, we show that diabetic red blood cells are more resistant to pneumolysin and the related toxin perfringolysin O relative to healthy red blood cells. Taken together, these studies indicate that the diversity of cell response to pneumolysin within a population of human red blood cells is influenced by the biophysical and biochemical status of the plasma membrane and the chemical and/or oxidative stress pre-history of the cell. PMID:26984406

Inflammatory reactions in placental blood of Plasmodium falciparum-infected women and high concentrations of soluble E-selectin and a circulating P. falciparum protein in the cord sera.

PubMed Central

Jakobsen, P H; Rasheed, F N; Bulmer, J N; Theisen, M; Ridley, R G; Greenwood, B M

1998-01-01

To better understand reasons for increased susceptibility to malaria in pregnancy; and the interrelationships between maternal malaria, local immune reactions and the development of the fetus, concentrations of soluble interleukin-10 (IL-10), cytokine receptors, adhesion molecules, a Plasmodium falciparum protein, glutamate-rich protein (GLURP) and antibodies to P. falciparum rhoptry-associated protein-1 were measured among 105 Gambian women and their neonates. Peripheral blood concentrations of IL-10, soluble cytokine receptors and soluble adhesion molecules were found to be different from those concentrations measured in the placenta. Markers of inflammatory reactions: IL-10, sIL-2R, sIL-4R, and soluble tumour necrosis factor receptor I (sTNF-RI) were found in high concentrations in the placenta, indicating that inflammatory reactions take place in the placenta which has been regarded as an immunoprivileged site. Concentrations of soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble intracellular adhesion molecule-1 (sICAM-1), potential adhesion receptors for malaria parasites, were associated with an active P. falciparum infection in the placenta although the associations did not reach significance. P. falciparum exoantigen, GLURP, was detected in cord blood indicating transplacental passage of malarial antigens. Concentrations of E-selectin were higher in cord blood samples compared with peripheral blood samples. This appeared to be associated with development of cord endothelial cells and not with P. falciparum infection. PMID:9616377

Chemically Attenuated Blood-Stage Plasmodium yoelii Parasites Induce Long-Lived and Strain-Transcending Protection

PubMed Central

Raja, Amber I.; Cai, Yeping; Reiman, Jennifer M.; Groves, Penny; Chakravarty, Sumana; McPhun, Virginia; Doolan, Denise L.; Cockburn, Ian; Hoffman, Stephen L.; Stanisic, Danielle I.

2016-01-01

The development of a vaccine is essential for the elimination of malaria. However, despite many years of effort, a successful vaccine has not been achieved. Most subunit vaccine candidates tested in clinical trials have provided limited efficacy, and thus attenuated whole-parasite vaccines are now receiving close scrutiny. Here, we test chemically attenuated Plasmodium yoelii 17X and demonstrate significant protection following homologous and heterologous blood-stage challenge. Protection against blood-stage infection persisted for at least 9 months. Activation of both CD4+ and CD8+ T cells was shown after vaccination; however, in vivo studies demonstrated a pivotal role for both CD4+ T cells and B cells since the absence of either cell type led to loss of vaccine-induced protection. In spite of significant activation of circulating CD8+ T cells, liver-stage immunity was not evident. Neither did vaccine-induced CD8+ T cells contribute to blood-stage protection; rather, these cells contributed to pathogenesis, since all vaccinated mice depleted of both CD4+ and CD8+ T cells survived a challenge infection. This study provides critical insight into whole-parasite vaccine-induced immunity and strong support for testing whole-parasite vaccines in humans. PMID:27245410

Haemosporidian parasite infections in grouse and ptarmigan: Prevalence and genetic diversity of blood parasites in resident Alaskan birds

USGS Publications Warehouse

Smith, Matthew M.; Van Hemert, Caroline R.; Merizon, Richard

2016-01-01

Projections related to future climate warming indicate the potential for an increase in the distribution and prevalence of blood parasites in northern regions. However, baseline data are lacking for resident avian host species in Alaska. Grouse and ptarmigan occupy a diverse range of habitat types throughout the northern hemisphere and are among the most well-known and important native game birds in North America. Information regarding the prevalence and diversity of haemosporidian parasites in tetraonid species is limited, with few recent studies and an almost complete lack of genetic data. To better understand the genetic diversity of haemosporidian parasites in Alaskan tetraonids and to determine current patterns of geographic range and host specificity, we used molecular methods to screen 459 tissue samples collected from grouse and ptarmigan species across multiple regions of Alaska for infection by Leucocytozoon, Haemoproteus, and Plasmodium blood parasites. Infections were detected in 342 individuals, with overall apparent prevalence of 53% for Leucocytozoon, 21% for Haemoproteus, and 9% for Plasmodium. Parasite prevalence varied by region, with different patterns observed between species groups (grouse versus ptarmigan). Leucocytozoon was more common in ptarmigan, whereas Haemoproteus was more common in grouse. We detected Plasmodium infections in grouse only. Analysis of haemosporidian mitochondrial DNA cytochrome b sequences revealed 23 unique parasite haplotypes, several of which were identical to lineages previously detected in other avian hosts. Phylogenetic analysis showed close relationships between haplotypes from our study and those identified in Alaskan waterfowl for Haemoproteus and Plasmodium parasites. In contrast, Leucocytozoon lineages were structured strongly by host family. Our results provide some of the first genetic data for haemosporidians in grouse and ptarmigan species, and provide an initial baseline on the prevalence and diversity

Acute respiratory distress syndrome and acute renal failure from Plasmodium ovale infection with fatal outcome.

PubMed

Lau, Yee-Ling; Lee, Wenn-Chyau; Tan, Lian-Huat; Kamarulzaman, Adeeba; Syed Omar, Sharifah Faridah; Fong, Mun-Yik; Cheong, Fei-Wen; Mahmud, Rohela

2013-11-04

Plasmodium ovale is one of the causative agents of human malaria. Plasmodium ovale infection has long been thought to be non-fatal. Due to its lower morbidity, P. ovale receives little attention in malaria research. Two Malaysians went to Nigeria for two weeks. After returning to Malaysia, they fell sick and were admitted to different hospitals. Plasmodium ovale parasites were identified from blood smears of these patients. The species identification was further confirmed with nested PCR. One of them was successfully treated with no incident of relapse within 12-month medical follow-up. The other patient came down with malaria-induced respiratory complication during the course of treatment. Although parasites were cleared off the circulation, the patient's condition worsened. He succumbed to multiple complications including acute respiratory distress syndrome and acute renal failure. Sequencing of the malaria parasite DNA from both cases, followed by multiple sequence alignment and phylogenetic tree construction suggested that the causative agent for both malaria cases was P. ovale curtisi. In this report, the differences between both cases were discussed, and the potential capability of P. ovale in causing severe complications and death as seen in this case report was highlighted. Plasmodium ovale is potentially capable of causing severe complications, if not death. Complete travel and clinical history of malaria patient are vital for successful diagnoses and treatment. Monitoring of respiratory and renal function of malaria patients, regardless of the species of malaria parasites involved is crucial during the course of hospital admission.

Optimization and inhibition of the adherent ability of Plasmodium falciparum-infected erythrocytes.

PubMed

Smith, H; Crandall, I; Prudhomme, J; Sherman, I W

1992-01-01

The vast majority of the 1-2 million malaria associated deaths that occur each year are due to anemia and cerebral malaria (the attachment of erythrocytes containing mature forms of Plasmodium falciparum to the endothelial cells that line the vascular beds of the brain). A "model system" for the study of cerebral malaria employs amelanotic melanoma cells as the "target" cells in an in vitro cytoadherence assay. Using this model system we determined that the optimum pH for adherence is 6.6 to 6.8, that high concentrations of Ca2+ (50mM) result in increased levels of binding, and that the type of buffer used influences adherence (Bis Tris > MOPS > HEPES > PIPES). We also observed that the ability of infected erythrocytes to cytoadhere varied from (erythrocyte) donor to donor. We have produced murine monoclonal antibodies against P. falciparum-infected red cells which recognize modified forms of human band 3; these inhibit the adherence of infected erythrocytes to melanoma cells in a dose-responsive fashion. Antimalarials (chloroquine, quinacrine, mefloquine, artemisinin), on the other hand, affected adherence in an indirect fashion i.e. since cytoadherence is due, in part, to the presence of knobs on the surface of the infected erythrocyte, and knob formation is dependent on intracellular parasite growth, when plasmodial development is inhibited so is knob production, and consequently adherence is ablated.

Spatial mapping and prediction of Plasmodium falciparum infection risk among school-aged children in Côte d'Ivoire.

PubMed

Houngbedji, Clarisse A; Chammartin, Frédérique; Yapi, Richard B; Hürlimann, Eveline; N'Dri, Prisca B; Silué, Kigbafori D; Soro, Gotianwa; Koudou, Benjamin G; Assi, Serge-Brice; N'Goran, Eliézer K; Fantodji, Agathe; Utzinger, Jürg; Vounatsou, Penelope; Raso, Giovanna

2016-09-07

In Côte d'Ivoire, malaria remains a major public health issue, and thus a priority to be tackled. The aim of this study was to identify spatially explicit indicators of Plasmodium falciparum infection among school-aged children and to undertake a model-based spatial prediction of P. falciparum infection risk using environmental predictors. A cross-sectional survey was conducted, including parasitological examinations and interviews with more than 5,000 children from 93 schools across Côte d'Ivoire. A finger-prick blood sample was obtained from each child to determine Plasmodium species-specific infection and parasitaemia using Giemsa-stained thick and thin blood films. Household socioeconomic status was assessed through asset ownership and household characteristics. Children were interviewed for preventive measures against malaria. Environmental data were gathered from satellite images and digitized maps. A Bayesian geostatistical stochastic search variable selection procedure was employed to identify factors related to P. falciparum infection risk. Bayesian geostatistical logistic regression models were used to map the spatial distribution of P. falciparum infection and to predict the infection prevalence at non-sampled locations via Bayesian kriging. Complete data sets were available from 5,322 children aged 5-16 years across Côte d'Ivoire. P. falciparum was the predominant species (94.5 %). The Bayesian geostatistical variable selection procedure identified land cover and socioeconomic status as important predictors for infection risk with P. falciparum. Model-based prediction identified high P. falciparum infection risk in the north, central-east, south-east, west and south-west of Côte d'Ivoire. Low-risk areas were found in the south-eastern area close to Abidjan and the south-central and west-central part of the country. The P. falciparum infection risk and related uncertainty estimates for school-aged children in Côte d'Ivoire represent the most up

Red blood cell sedimentation of Apheresis Granulocytes.

PubMed

Lodermeier, Michelle A; Byrne, Karen M; Flegel, Willy A

2017-10-01

Sedimentation of Apheresis Granulocyte components removes red blood cells. It is used to increase the blood donor pool when blood group-compatible donors cannot be recruited for a patient because of a major ABO incompatibility or incompatible red blood cell antibodies in the recipient. Because granulocytes have little ABO and few other red blood cell antigens on their membrane, such incompatibility lies mostly with the contaminating red blood cells. Video Clip S1 shows the process of red blood cell sedimentation of an Apheresis Granulocyte component. This video was filmed with a single smart phone attached to a commercial tripod and was edited on a tablet computer with free software by an amateur videographer without prior video experience. © 2017 AABB.

Red Cross and federal government held liable for hemophiliacs' HIV infection.

PubMed

Elliott, R

2000-01-01

After eight years of litigation, on 21 June 2000 three hemophiliacs infected with HIV finally won a judgment against the Canadian Red Cross Society and the federal government. An Ontario trial court ruled the Red Cross and the government were negligent for having delayed the implementation of heat treatment for blood products, which resulted in the plaintiffs' infections. Since starting their lawsuits in 1992, two of the three plaintiffs died of AIDS before the trial judgment. But the damage awards were criticized by the plaintiffs' lawyer.

Strict tropism for CD71+/CD234+ human reticulocytes limits the zoonotic potential of Plasmodium cynomolgi

PubMed Central

Kosaisavee, Varakorn; Suwanarusk, Rossarin; Chua, Adeline C. Y.; Kyle, Dennis E.; Malleret, Benoit; Zhang, Rou; Imwong, Mallika; Imerbsin, Rawiwan; Ubalee, Ratawan; Sámano-Sánchez, Hugo; Yeung, Bryan K. S.; Ong, Jessica J. Y.; Lombardini, Eric; Nosten, François; Tan, Kevin S. W.; Bifani, Pablo; Snounou, Georges; Rénia, Laurent

2017-01-01

Two malaria parasites of Southeast Asian macaques, Plasmodium knowlesi and P cynomolgi, can infect humans experimentally. In Malaysia, where both species are common, zoonotic knowlesi malaria has recently become dominant, and cases are recorded throughout the region. By contrast, to date, only a single case of naturally acquired P cynomolgi has been found in humans. In this study, we show that whereas P cynomolgi merozoites invade monkey red blood cells indiscriminately in vitro, in humans, they are restricted to reticulocytes expressing both transferrin receptor 1 (Trf1 or CD71) and the Duffy antigen/chemokine receptor (DARC or CD234). This likely contributes to the paucity of detectable zoonotic cynomolgi malaria. We further describe postinvasion morphologic and rheologic alterations in P cynomolgi–infected human reticulocytes that are strikingly similar to those observed for P vivax. These observations stress the value of P cynomolgi as a model in the development of blood stage vaccines against vivax malaria. PMID:28698207

Plasmodium falciparum polypeptides released during in vitro cultivation*

PubMed Central

Da Silva, L. Rodriguez; Loche, M.; Dayal, R.; Perrin, L. H.

1983-01-01

Synchronous cultures of Plasmodium falciparum were successively labelled with (35S)-methionine and both the supernatants and the pellets of infected red blood cells were collected. The release of TCA-precipitable material in the culture supernatants was low during the development of ring forms and trophozoites, increased during schizogony, and was maximum at the time of schizont rupture and merozoite reinvasion. Analysis of the supernatants by SDS — PAGE and autoradiography showed that both polypeptides common to the various developmental stages of the parasite and schizont/merozoite-specific polypeptides were released. Polypeptides of relative molecular mass 140 000, 82 000 and, to a lower degree, 41 000 were present in high amounts in the culture supernatants. These polypeptides have been shown to be the target of monoclonal antibodies that are able to inhibit the growth of P. falciparum cultures, and may be involved in protective immunity. The released polypeptides may also be used as target antigens in immunodiagnostic tests aiming at the detection of malaria infection. ImagesFig. 2AFig. 2BFig. 3 PMID:6340846

Evidence of non-Plasmodium falciparum malaria infection in Kédougou, Sénégal.

PubMed

Daniels, Rachel F; Deme, Awa Bineta; Gomis, Jules F; Dieye, Baba; Durfee, Katelyn; Thwing, Julie I; Fall, Fatou B; Ba, Mady; Ndiop, Medoune; Badiane, Aida S; Ndiaye, Yaye Die; Wirth, Dyann F; Volkman, Sarah K; Ndiaye, Daouda

2017-01-03

Expanded malaria control efforts in Sénégal have resulted in increased use of rapid diagnostic tests (RDT) to identify the primary disease-causing Plasmodium species, Plasmodium falciparum. However, the type of RDT utilized in Sénégal does not detect other malaria-causing species such as Plasmodium ovale spp., Plasmodium malariae, or Plasmodium vivax. Consequently, there is a lack of information about the frequency and types of malaria infections occurring in Sénégal. This study set out to better determine whether species other than P. falciparum were evident among patients evaluated for possible malaria infection in Kédougou, Sénégal. Real-time polymerase chain reaction speciation assays for P. vivax, P. ovale spp., and P. malariae were developed and validated by sequencing and DNA extracted from 475 Plasmodium falciparum-specific HRP2-based RDT collected between 2013 and 2014 from a facility-based sample of symptomatic patients from two health clinics in Kédougou, a hyper-endemic region in southeastern Sénégal, were analysed. Plasmodium malariae (n = 3) and P. ovale wallikeri (n = 2) were observed as co-infections with P. falciparum among patients with positive RDT results (n = 187), including one patient positive for all three species. Among 288 negative RDT samples, samples positive for P. falciparum (n = 24), P. ovale curtisi (n = 3), P. ovale wallikeri (n = 1), and P. malariae (n = 3) were identified, corresponding to a non-falciparum positivity rate of 2.5%. These findings emphasize the limitations of the RDT used for malaria diagnosis and demonstrate that non-P. falciparum malaria infections occur in Sénégal. Current RDT used for routine clinical diagnosis do not necessarily provide an accurate reflection of malaria transmission in Kédougou, Sénégal, and more sensitive and specific methods are required for diagnosis and patient care, as well as surveillance and elimination activities. These findings have implications for other

HGF Secreted by Activated Kupffer Cells Induces Apoptosis of Plasmodium-Infected Hepatocytes

PubMed Central

Gonçalves, Lígia Antunes; Rodo, Joana; Rodrigues-Duarte, Lurdes; de Moraes, Luciana Vieira; Penha-Gonçalves, Carlos

2017-01-01

Malaria liver stage infection is an obligatory parasite development step and represents a population bottleneck in Plasmodium infections, providing an advantageous target for blocking parasite cycle progression. Parasite development inside hepatocytes implies a gross cellular insult evoking innate host responses to counteract intra-hepatocytic infection. Using primary hepatocyte cultures, we investigated the role of Kupffer cell-derived hepatocyte growth factor (HGF) in malaria liver stage infection. We found that Kupffer cells from Plasmodium-infected livers produced high levels of HGF, which trigger apoptosis of infected hepatocytes through a mitochondrial-independent apoptosis pathway. HGF action in infected hepatocyte primary cultures results in a potent reduction of parasite yield by specifically sensitizing hepatocytes carrying established parasite exo-erythrocytic forms to undergo apoptosis. This apoptosis mechanism is distinct from cell death that is spontaneously induced in infected cultures and is governed by Fas signaling modulation through a mitochondrial-dependent apoptosis pathway. This work indicates that HGF and Fas signaling pathways are part of an orchestrated host apoptosis response that occurs during malaria liver stage infection, decreasing the success of infection of individual hepatocytes. Our results raise the hypothesis that paracrine signals derived from Kupffer cell activation are implicated in directing death of hepatocytes infected with the malaria parasite. PMID:28220125

HGF Secreted by Activated Kupffer Cells Induces Apoptosis of Plasmodium-Infected Hepatocytes.

PubMed

Gonçalves, Lígia Antunes; Rodo, Joana; Rodrigues-Duarte, Lurdes; de Moraes, Luciana Vieira; Penha-Gonçalves, Carlos

2017-01-01

Malaria liver stage infection is an obligatory parasite development step and represents a population bottleneck in Plasmodium infections, providing an advantageous target for blocking parasite cycle progression. Parasite development inside hepatocytes implies a gross cellular insult evoking innate host responses to counteract intra-hepatocytic infection. Using primary hepatocyte cultures, we investigated the role of Kupffer cell-derived hepatocyte growth factor (HGF) in malaria liver stage infection. We found that Kupffer cells from Plasmodium -infected livers produced high levels of HGF, which trigger apoptosis of infected hepatocytes through a mitochondrial-independent apoptosis pathway. HGF action in infected hepatocyte primary cultures results in a potent reduction of parasite yield by specifically sensitizing hepatocytes carrying established parasite exo-erythrocytic forms to undergo apoptosis. This apoptosis mechanism is distinct from cell death that is spontaneously induced in infected cultures and is governed by Fas signaling modulation through a mitochondrial-dependent apoptosis pathway. This work indicates that HGF and Fas signaling pathways are part of an orchestrated host apoptosis response that occurs during malaria liver stage infection, decreasing the success of infection of individual hepatocytes. Our results raise the hypothesis that paracrine signals derived from Kupffer cell activation are implicated in directing death of hepatocytes infected with the malaria parasite.

Plasmodium ovale in Indonesia.

PubMed

Baird, J K; Purnomo; Masbar, S

1990-12-01

We report 34 infections by Plasmodium ovale found among 15,806 blood film examinations taken between 1973 and 1989 from several sites in Indonesia. Twenty five of the P. ovale infections occurred in a single sample of 514 people living in Owi, Irian Jaya. We detected five additional infections at 3 other sites in Irian Jaya. Other infections by P. ovale occurred at two sites in West Flores. Another infection has already been reported from East Timor. Despite relatively frequent sampling of populations on Sumatra, Kalimantan, Java and Sulawesi, P. ovale has not been found on those islands. It appears that this parasite occurs only on the easternmost islands of the Indonesian archipelago where it is nonetheless a rare finding.

Molecular detection of Plasmodium in free-ranging birds and captive flamingos (Phoenicopterus chilensis) in Chicago.

PubMed

Thurber, Mary Irene; Gamble, Kathryn C; Krebs, Bethany; Goldberg, Tony L

2014-12-01

Frozen blood samples from 13 species of free-ranging birds (n = 65) and captive Chilean flamingos (Phoenicopterus chilensis) (n = 46) housed outdoors in the Chicago area were screened for Plasmodium. With the use of a modified polymerase chain reaction, 20/65 (30.8%) of free-ranging birds and 26/46 (56.5%) of flamingos were classified as positive for this parasite genus. DNA sequencing of the parasite cytochrome b gene in positive samples demonstrated that eight species of free-ranging birds were infected with five different Plasmodium spp. cytochrome b lineages, and all positive Chilean flamingos were infected with Plasmodium spp. cytochrome b lineages most closely related to organisms in the Novyella subgenus. These results show that Chilean flamingos may harbor subclinical malaria infections more frequently than previously estimated, and that they may have increased susceptibility to some Plasmodium species.

Using infective mosquitoes to challenge monkeys with Plasmodium knowlesi in malaria vaccine studies.

PubMed

Murphy, Jittawadee R; Weiss, Walter R; Fryauff, David; Dowler, Megan; Savransky, Tatyana; Stoyanov, Cristina; Muratova, Olga; Lambert, Lynn; Orr-Gonzalez, Sachy; Zeleski, Katie Lynn; Hinderer, Jessica; Fay, Michael P; Joshi, Gyan; Gwadz, Robert W; Richie, Thomas L; Villasante, Eileen Franke; Richardson, Jason H; Duffy, Patrick E; Chen, Jingyang

2014-06-03

When rhesus monkeys (Macaca mulatta) are used to test malaria vaccines, animals are often challenged by the intravenous injection of sporozoites. However, natural exposure to malaria comes via mosquito bite, and antibodies can neutralize sporozoites as they traverse the skin. Thus, intravenous injection may not fairly assess humoral immunity from anti-sporozoite malaria vaccines. To better assess malaria vaccines in rhesus, a method to challenge large numbers of monkeys by mosquito bite was developed. Several species and strains of mosquitoes were tested for their ability to produce Plasmodium knowlesi sporozoites. Donor monkey parasitaemia effects on oocyst and sporozoite numbers and mosquito mortality were documented. Methylparaben added to mosquito feed was tested to improve mosquito survival. To determine the number of bites needed to infect a monkey, animals were exposed to various numbers of P. knowlesi-infected mosquitoes. Finally, P. knowlesi-infected mosquitoes were used to challenge 17 monkeys in a malaria vaccine trial, and the effect of number of infectious bites on monkey parasitaemia was documented. Anopheles dirus, Anopheles crascens, and Anopheles dirus X (a cross between the two species) produced large numbers of P. knowlesi sporozoites. Mosquito survival to day 14, when sporozoites fill the salivary glands, averaged only 32% when donor monkeys had a parasitaemia above 2%. However, when donor monkey parasitaemia was below 2%, mosquitoes survived twice as well and contained ample sporozoites in their salivary glands. Adding methylparaben to sugar solutions did not improve survival of infected mosquitoes. Plasmodium knowlesi was very infectious, with all monkeys developing blood stage infections if one or more infected mosquitoes successfully fed. There was also a dose-response, with monkeys that received higher numbers of infected mosquito bites developing malaria sooner. Anopheles dirus, An. crascens and a cross between these two species all were

Avian Plasmodium infection in field-collected mosquitoes during 2012-2013 in Tarlac, Philippines.

PubMed

Chen, Tien-Huang; Aure, Wilfredo E; Cruz, Estrella Irlandez; Malbas, Fedelino F; Teng, Hwa-Jen; Lu, Liang-Chen; Kim, Kyeong Soon; Tsuda, Yoshio; Shu, Pei-Yun

2015-12-01

Global warming threatens to increase the spread and prevalence of mosquito-transmitted diseases. Certain pathogens may be carried by migratory birds and transmitted to local mosquito populations. Mosquitoes were collected in the northern Philippines during bird migration seasons to detect avian malaria parasites as well as for the identification of potential vector species and the estimation of infections among local mosquito populations. We used the nested PCR to detect the avian malaria species. Culex vishnui (47.6%) was the most abundant species collected and Cx. tritaeniorhynchus (13.8%) was the second most abundant. Avian Plasmodium parasites were found in eight mosquito species, for which the infection rates were between 0.5% and 6.2%. The six Plasmodium genetic lineages found in this study included P. juxtanucleare -GALLUS02, Tacy7 (Donana04), CXBIT01, Plasmodium species LIN2 New Zealand, and two unclassified lineages. The potential mosquito vectors for avian Plasmodium parasites in the Philippines were Cq. crassipes, Cx. fuscocephala, Cx. quinquefasciatus, Cx. sitiens, Cx. vishnui, and Ma. Uniformis; two major genetic lineages, P. juxtanucleare and Tacy7, were identified. © 2015 The Society for Vector Ecology.

Detection of avian malaria (Plasmodium spp.) in native land birds of American Samoa

USGS Publications Warehouse

Jarvi, S.I.; Farias, M.E.M.; Baker, H.; Freifeld, H.B.; Baker, P.E.; Van Gelder, E.; Massey, J.G.; Atkinson, C.T.

2003-01-01

This study documents the presence of Plasmodium spp. in landbirds of central Polynesia. Blood samples collected from eight native and introduced species from the island of Tutuila, American Samoa were evaluated for the presence of Plasmodium spp. by nested rDNA PCR, serology and/or microscopy. A total of 111/188 birds (59%) screened by nested PCR were positive. Detection of Plasmodium spp. was verified by nucleotide sequence comparisons of partial 18S ribosomal RNA and TRAP (thrombospondin-related anonymous protein) genes using phylogenetic analyses. All samples screened by immunoblot to detect antibodies that cross-react with Hawaiian isolates of Plasmodium relictum (153) were negative. Lack of cross-reactivity is probably due to antigenic differences between the Hawaiian and Samoan Plasmodium isolates. Similarly, all samples examined by microscopy (214) were negative. The fact that malaria is present, but not detectable by blood smear evaluation is consistent with low peripheral parasitemia characteristic of chronic infections. High prevalence of apparently chronic infections, the relative stability of the native land bird communities, and the presence of mosquito vectors which are considered endemic and capable of transmitting avian Plasmodia, suggest that these parasites are indigenous to Samoa and have a long coevolutionary history with their hosts.

Monitoring of Plasmodium infection in humans and potential vectors of malaria in a newly emerged focus in southern Iran

PubMed Central

Kalantari, Mohsen; Soltani, Zahra; Ebrahimi, Mostafa; Yousefi, Masoud; Amin, Masoumeh; Shafiei, Ayda; Azizi, Kourosh

2017-01-01

Despite control programs, which aim to eliminate malaria from Iran by 2025, transmission of malaria has not been removed from the country. This study aimed to monitor malaria from asymptomatic parasitaemia and clinical cases from about one year of active case surveillance and potential vectors of malaria in the newly emerged focus of Mamasani and Rostam, southern Iran during 2014–2015. Samples were collected and their DNAs were extracted for Polymerase Chain Reaction (PCR) assay using specific primers for detection of Plasmodium species. The Annual Parasite Incidence rate (API) was three cases per 1,000 population from 2,000 individuals in three villages. Parasites species were detected in 9 out of the 4,000 blood smear samples among which, 6 cases were indigenous and had no history of travels to endemic areas of malaria. Also, the prevalence rate of asymptomatic parasites was about 0.3%. Overall, 1073 Anopheles spp. were caught from 9 villages. Totally, 512 female samples were checked by PCR, which indicated that none of them was infected with Plasmodium. Despite new malaria local transmission in humans in Mamasani and Rostam districts, no infection with Plasmodium was observed in Anopheles species. Because of neighboring of the studied area to the re-emerged focus in Fars province (Kazerun) and important endemic foci of malaria in other southern provinces, such as Hormozgan and Kerman, monitoring of the vectors and reservoir hosts of Plasmodium species would be unavoidable. Application of molecular methods, such as PCR, can simplify access to the highest level of accuracy in malaria researches. PMID:28078947

Plasmodium malariae in the Colombian Amazon region: you don't diagnose what you don't suspect.

PubMed

Niño, Carlos Hernando; Cubides, Juan Ricardo; Camargo-Ayala, Paola Andrea; Rodríguez-Celis, Carlos Arturo; Quiñones, Teódulo; Cortés-Castillo, Moisés Tomás; Sánchez-Suárez, Lizeth; Sánchez, Ricardo; Patarroyo, Manuel Elkin; Patarroyo, Manuel Alfonso

2016-11-29

Malaria is a worldwide public health problem; parasites from the genus Plasmodium spp. are the aetiological agent of this disease. The parasite is mainly diagnosed by microscope-based techniques. However, these have limited sensitivity. Many asymptomatic infections are sub-microscopic and can only be detected by molecular methods. This study was aimed at comparing nested PCR results to those obtained by microscope for diagnosing malaria and to present epidemiological data regarding malaria in Colombia's Amazon department. A total of 1392 blood samples (taken by venepuncture) from symptomatic patients in Colombia's Amazon department were analysed in parallel by thick blood smear (TBS) test and nested PCR for determining Plasmodium spp. infection and identifying infecting species, such as Plasmodium vivax, Plasmodium malariae and/or Plasmodium falciparum. Descriptive statistics were used for comparing the results from both tests regarding detection of the disease, typing infecting species and their prevalence in the study region. Bearing the microscope assay in mind as gold standard, PCR diagnosis performance was evaluated by statistical indicators. The present study revealed great differences between both diagnostic tests, as well as suggesting high P. malariae prevalence from a molecular perspective. This differed profoundly from previous studies in this region of Colombia, usually based on the TBS test, suggesting that diagnosis by conventional techniques could lead to underestimating the prevalence of certain Plasmodium spp. having high circulation in this area. The present results highlight the need for modifying state malaria surveillance schemes for more efficient strategies regarding the detection of this disease in endemic areas. The importance of PCR as a back-up test in cases of low parasitaemia or mixed infection is also highlighted.

Mortality and pathology in birds due to Plasmodium (Giovannolaia) homocircumflexum infection, with emphasis on the exoerythrocytic development of avian malaria parasites.

PubMed

Ilgūnas, Mikas; Bukauskaitė, Dovilė; Palinauskas, Vaidas; Iezhova, Tatjana A; Dinhopl, Nora; Nedorost, Nora; Weissenbacher-Lang, Christiane; Weissenböck, Herbert; Valkiūnas, Gediminas

2016-05-04

Species of avian malaria parasites (Plasmodium) are widespread, but their virulence has been insufficiently investigated, particularly in wild birds. During avian malaria, several cycles of tissue merogony occur, and many Plasmodium spp. produce secondary exoerythrocytic meronts (phanerozoites), which are induced by merozoites developing in erythrocytic meronts. Phanerozoites markedly damage organs, but remain insufficiently investigated in the majority of described Plasmodium spp. Avian malaria parasite Plasmodium (Giovannolaia) homocircumflexum (lineage pCOLL4) is virulent and produces phanerozoites in domestic canaries Serinus canaria, but its pathogenicity in wild birds remains unknown. The aim of this study was to investigate the pathology caused by this infection in species of common European birds. One individual of Eurasian siskin Carduelis spinus, common crossbill Loxia curvirostra and common starling Sturnus vulgaris were exposed to P. homocircumflexum infection by intramuscular sub-inoculation of infected blood. The birds were maintained in captivity and parasitaemia was monitored until their death due to malaria. Brain, heart, lungs, liver, spleen, kidney, and a piece of breast muscle were examined using histology and chromogenic in situ hybridization (ISH) methods. All exposed birds developed malaria infection, survived the peak of parasitaemia, but suddenly died between 30 and 38 days post exposure when parasitaemia markedly decreased. Numerous phanerozoites were visible in histological sections of all organs and were particularly easily visualized after ISH processing. Blockage of brain capillaries with phanerozoites may have led to cerebral ischaemia, causing cerebral paralysis and is most likely the main reason of sudden death of all infected individuals. Inflammatory response was not visible around the brain, heart and muscle phanerozoites, and it was mild in parenchymal organs. The endothelial damage likely causes dysfunction and failure of

Red blood cell decreases of microgravity

NASA Technical Reports Server (NTRS)

Johnson, P. C.

1985-01-01

Postflight decreases in red blood cell mass (RBCM) have regularly been recorded after exposure to microgravity. These 5-25 percent decreases do not relate to the mission duration, workload, caloric intake or to the type of spacecraft used. The decrease is accompanied by normal red cell survivals, increased ferritin levels, normal radioactive iron studies, and increases in mean red blood cell volume. Comparable decreases in red blood cell mass are not found after bed rest, a commonly used simulation of the microgravity state. Inhibited bone marrow erythropoiesis has not been proven to date, although reticulocyte numbers in the peripheral circulation are decreased about 50 percent. To date, the cause of the microgravity induced decreases in RBCM is unknown. Increased splenic trapping of circulating red blood cells seem the most logical way to explain the results obtained.

Continuous Supply of Plasmodium vivax Sporozoites from Colonized Anopheles darlingi in the Peruvian Amazon

PubMed Central

2018-01-01

In vitro culture of Plasmodium vivax liver stages underlies key understandings of the fundamental biology of this parasite, particularly the latent, hyponozoite stage, toward drug and vaccine development. Here, we report systematic production of Plasmodium vivax sporozoites in colonized Anopheles darlingi mosquitoes in the Peruvian Amazon. Human subject-derived P. vivax-infected blood was fed to Anopheles darlingi females using standard membrane feedings assays. Optimizing A. darlingi infection and sporozoite production included replacement of infected patient donor serum with naïve donor serum, comparing anticoagulants in processing blood samples, and addition of penicillin–streptomycin and ATP to infectious blood meals. Replacement of donor serum by naïve serum in the P. vivax donor blood increased oocysts in the mosquito midgut, and heparin, as anticoagulant, was associated with the highest sporozoite yields. Maintaining blood-fed mosquitoes on penicillin–streptomycin in sugar significantly extended mosquito survival which enabled greater sporozoite yield. In this study, we have shown that a robust P. vivax sporozoite production is feasible in a malaria-endemic setting where infected subjects and a stable A. darlingi colony are brought together, with optimized laboratory conditions. PMID:29465219

Continuous Supply of Plasmodium vivax Sporozoites from Colonized Anopheles darlingi in the Peruvian Amazon.

PubMed

Moreno, Marta; Tong-Rios, Carlos; Orjuela-Sanchez, Pamela; Carrasco-Escobar, Gabriel; Campo, Brice; Gamboa, Dionicia; Winzeler, Elizabeth A; Vinetz, Joseph M

2018-04-13

In vitro culture of Plasmodium vivax liver stages underlies key understandings of the fundamental biology of this parasite, particularly the latent, hyponozoite stage, toward drug and vaccine development. Here, we report systematic production of Plasmodium vivax sporozoites in colonized Anopheles darlingi mosquitoes in the Peruvian Amazon. Human subject-derived P. vivax-infected blood was fed to Anopheles darlingi females using standard membrane feedings assays. Optimizing A. darlingi infection and sporozoite production included replacement of infected patient donor serum with naïve donor serum, comparing anticoagulants in processing blood samples, and addition of penicillin-streptomycin and ATP to infectious blood meals. Replacement of donor serum by naïve serum in the P. vivax donor blood increased oocysts in the mosquito midgut, and heparin, as anticoagulant, was associated with the highest sporozoite yields. Maintaining blood-fed mosquitoes on penicillin-streptomycin in sugar significantly extended mosquito survival which enabled greater sporozoite yield. In this study, we have shown that a robust P. vivax sporozoite production is feasible in a malaria-endemic setting where infected subjects and a stable A. darlingi colony are brought together, with optimized laboratory conditions.

Isolation of invasive Plasmodium yoelii merozoites with a long half-life to evaluate invasion dynamics and potential invasion inhibitors.

PubMed

Mutungi, Joe Kimanthi; Yahata, Kazuhide; Sakaguchi, Miako; Kaneko, Osamu

2015-11-01

Malaria symptoms and pathogenesis are caused by blood stage parasite burdens of Plasmodium spp., for which invasion of red blood cells (RBCs) by merozoites is essential. Successful targeting by either drugs or vaccines directed against the whole merozoite or its antigens during its transient extracellular status would contribute to malaria control by impeding RBC invasion. To understand merozoite invasion biology and mechanisms, it is desired to obtain merozoites that retain their invasion activity in vitro. Accordingly, methods have been developed to isolate invasive Plasmodium knowlesi and Plasmodium falciparum merozoites. Rodent malaria parasite models offer ease in laboratory maintenance and experimental genetic modifications; however, no methods have been reported regarding isolation of high numbers of invasive rodent malaria merozoites. In this study, Plasmodium yoelii-infected RBCs were obtained from infected mice, and mature schizont-infected RBCs enriched via Histodenz™ density gradients. Merozoites retaining invasion activity were then isolated by passing the preparations through a filter membrane. RBC-invaded parasites developed to mature stages in vitro in a synchronous manner. Isolated merozoites were evaluated for retention of invasion activity following storage at different temperatures prior to incubation with uninfected mouse RBCs. Isolated merozoites retained their invasion activity 4h after isolation at 10 or 15 °C, whereas their invasion activity reduced to 0-10% within 30 min when incubated on ice or at 37 °C prior to RBC invasion assay. Images of merozoites at successive steps during RBC invasion were captured by light and transmission electron microscopy. Synthetic peptides derived from the amino acid sequence of the P. yoelii invasion protein RON2 efficiently inhibited RBC invasion. The developed method to isolate and keep invasive P. yoelii merozoites for up to 4h is a powerful tool to study the RBC invasion biology of this parasite

Acute respiratory distress syndrome and acute renal failure from Plasmodium ovale infection with fatal outcome

PubMed Central

2013-01-01

Background Plasmodium ovale is one of the causative agents of human malaria. Plasmodium ovale infection has long been thought to be non-fatal. Due to its lower morbidity, P. ovale receives little attention in malaria research. Methods Two Malaysians went to Nigeria for two weeks. After returning to Malaysia, they fell sick and were admitted to different hospitals. Plasmodium ovale parasites were identified from blood smears of these patients. The species identification was further confirmed with nested PCR. One of them was successfully treated with no incident of relapse within 12-month medical follow-up. The other patient came down with malaria-induced respiratory complication during the course of treatment. Although parasites were cleared off the circulation, the patient’s condition worsened. He succumbed to multiple complications including acute respiratory distress syndrome and acute renal failure. Results Sequencing of the malaria parasite DNA from both cases, followed by multiple sequence alignment and phylogenetic tree construction suggested that the causative agent for both malaria cases was P. ovale curtisi. Discussion In this report, the differences between both cases were discussed, and the potential capability of P. ovale in causing severe complications and death as seen in this case report was highlighted. Conclusion Plasmodium ovale is potentially capable of causing severe complications, if not death. Complete travel and clinical history of malaria patient are vital for successful diagnoses and treatment. Monitoring of respiratory and renal function of malaria patients, regardless of the species of malaria parasites involved is crucial during the course of hospital admission. PMID:24180319

Do the venous blood samples replicate malaria parasite densities found in capillary blood? A field study performed in naturally-infected asymptomatic children in Cameroon.

PubMed

Sandeu, Maurice M; Bayibéki, Albert N; Tchioffo, Majoline T; Abate, Luc; Gimonneau, Geoffrey; Awono-Ambéné, Parfait H; Nsango, Sandrine E; Diallo, Diadier; Berry, Antoine; Texier, Gaétan; Morlais, Isabelle

2017-08-17

The measure of new drug- or vaccine-based approaches for malaria control is based on direct membrane feeding assays (DMFAs) where gametocyte-infected blood samples are offered to mosquitoes through an artificial feeder system. Gametocyte donors are identified by the microscopic detection and quantification of malaria blood stages on blood films prepared using either capillary or venous blood. However, parasites are known to sequester in the microvasculature and this phenomenon may alter accurate detection of parasites in blood films. The blood source may then impact the success of mosquito feeding experiments and investigations are needed for the implementation of DMFAs under natural conditions. Thick blood smears were prepared from blood obtained from asymptomatic children attending primary schools in the vicinity of Mfou (Cameroon) over four transmission seasons. Parasite densities were determined microscopically from capillary and venous blood for 137 naturally-infected gametocyte carriers. The effect of the blood source on gametocyte and asexual stage densities was then assessed by fitting cumulative link mixed models (CLMM). DMFAs were performed to compare the infectiousness of gametocytes from the different blood sources to mosquitoes. Prevalence of Plasmodium falciparum asexual stages among asymptomatic children aged from 4 to 15 years was 51.8% (2116/4087). The overall prevalence of P. falciparum gametocyte carriage was 8.9% and varied from one school to another. No difference in the density of gametocyte and asexual stages was found between capillary and venous blood. Attempts to perform DMFAs with capillary blood failed. Plasmodium falciparum malaria parasite densities do not differ between capillary and venous blood in asymptomatic subjects for both gametocyte and trophozoite stages. This finding suggests that the blood source should not interfere with transmission efficiency in DMFAs.

Holographic analysis on deformation and restoration of malaria-infected red blood cells by antimalarial drug

NASA Astrophysics Data System (ADS)

Byeon, Hyeokjun; Ha, Young-Ran; Lee, Sang Joon

2015-11-01

Malaria parasites induce morphological, biochemical, and mechanical changes in red blood cells (RBCs). Mechanical variations are closely related to the deformability of individual RBCs. The deformation of various RBCs, including healthy and malaria-infected RBCs (iRBCs), can be directly observed through quantitative phase imaging (QPI). The effects of chloroquine treatment on the mechanical property variation of iRBCs were investigated using time-resolved holographic QPI of single live cells on a millisecond time scale. The deformabilities of healthy RBCs, iRBCs, and drug-treated iRBCs were compared, and the effect of chloroquine on iRBC restoration was experimentally examined. The present results are beneficial to elucidate the dynamic characteristics of iRBCs and the effect of the antimalarial drug on iRBCs.

Holographic analysis on deformation and restoration of malaria-infected red blood cells by antimalarial drug.

PubMed

Byeon, Hyeokjun; Ha, Young-Ran; Lee, Sang Joon

2015-11-01

Malaria parasites induce morphological, biochemical, and mechanical changes in red blood cells (RBCs). Mechanical variations are closely related to the deformability of individual RBCs. The deformation of various RBCs, including healthy and malaria-infected RBCs (iRBCs), can be directly observed through quantitative phase imaging (QPI). The effects of chloroquine treatment on the mechanical property variation of iRBCs were investigated using time-resolved holographic QPI of single live cells on a millisecond time scale. The deformabilities of healthy RBCs, iRBCs, and drug-treated iRBCs were compared, and the effect of chloroquine on iRBC restoration was experimentally examined. The present results are beneficial to elucidate the dynamic characteristics of iRBCs and the effect of the antimalarial drug on iRBCs.

Comparison of rapid diagnostic test Plasmotec Malaria-3, microscopy, and quantitative real-time PCR for diagnoses of Plasmodium falciparum and Plasmodium vivax infections in Mimika Regency, Papua, Indonesia.

PubMed

Fransisca, Liony; Kusnanto, Josef Hari; Satoto, Tri Baskoro T; Sebayang, Boni; Supriyanto; Andriyan, Eko; Bangs, Michael J

2015-03-05

The World Health Organization recommends malaria be diagnosed by standard microscopy or rapid diagnostic test (RDT) before treatment. RDTs have been used with greater frequency in the absence of matching blood slide confirmation in the majority of RDT reported cases in Mimika Regency, Papua Province, Indonesia. Given the importance of RDT in current health system as point-of-care tool, careful validation of RDT product performance for providing accurate malaria diagnosis is critical. Plasmotec Malaria-3 (XW-P07) performance was evaluated by comparing it with paired blood film microscopy and quantitative real-time PCR (qPCR). Consecutive whole blood samples were derived from one clinic in Mimika as part of routine passive malaria case detection. RDT results were read by two trained technicians and interpreted by consensus. Expert microscopic examination of blood slides was cross-checked by observer-blinded second reader and a third examiner if discordant between examinations. qPCR was used as the 'gold standard', followed by microscopy for the outcome/disease variable. Comparison analysis included sensitivity (Sn), specificity (Sp), positive and negative predictive values (PPV & NPV), and other diagnostic screening performance measures for detecting Plasmodium falciparum and Plasmodium vivax infections. Overall malaria positive samples from qPCR was 42.2% (175/415 samples); and from matching blood slides 40.5% (168/415) of which those infections with relatively low parasite densities ≤100/μl blood was 5.7% of P. falciparum and 16.5% of P. vivax samples examined. Overall RDT performance when compared with microscopy for detecting P. falciparum was Sn:92%, Sp:96.6%, PPV:88%, NPV:97.8%, Kappa:0.87; and for P. vivax Sn:72.9%, Sp:99.1%, PPV:95.4%, NPV:93.4%, Kappa:0.79. Overall RDT performance when compared with qPCR for detecting P. falciparum was Sn:92%, Sp:96.6%, PPV:88%, NPV:97.8%, Kappa:0.87; and for P. vivax Sn:66%, Sp:99.1%, PPV:95.4%, NPV:90.9%, Kappa:0

Optimization of flow cytometric detection and cell sorting of transgenic Plasmodium parasites using interchangeable optical filters

PubMed Central

2012-01-01

Background Malaria remains a major cause of morbidity and mortality worldwide. Flow cytometry-based assays that take advantage of fluorescent protein (FP)-expressing malaria parasites have proven to be valuable tools for quantification and sorting of specific subpopulations of parasite-infected red blood cells. However, identification of rare subpopulations of parasites using green fluorescent protein (GFP) labelling is complicated by autofluorescence (AF) of red blood cells and low signal from transgenic parasites. It has been suggested that cell sorting yield could be improved by using filters that precisely match the emission spectrum of GFP. Methods Detection of transgenic Plasmodium falciparum parasites expressing either tdTomato or GFP was performed using a flow cytometer with interchangeable optical filters. Parasitaemia was evaluated using different optical filters and, after optimization of optics, the GFP-expressing parasites were sorted and analysed by microscopy after cytospin preparation and by imaging cytometry. Results A new approach to evaluate filter performance in flow cytometry using two-dimensional dot blot was developed. By selecting optical filters with narrow bandpass (BP) and maximum position of filter emission close to GFP maximum emission in the FL1 channel (510/20, 512/20 and 517/20; dichroics 502LP and 466LP), AF was markedly decreased and signal-background improve dramatically. Sorting of GFP-expressing parasite populations in infected red blood cells at 90 or 95% purity with these filters resulted in 50-150% increased yield when compared to the standard filter set-up. The purity of the sorted population was confirmed using imaging cytometry and microscopy of cytospin preparations of sorted red blood cells infected with transgenic malaria parasites. Discussion Filter optimization is particularly important for applications where the FP signal and percentage of positive events are relatively low, such as analysis of parasite-infected

Alterations in cytokines and haematological parameters during the acute and convalescent phases of Plasmodium falciparum and Plasmodium vivax infections.

PubMed

Rodrigues-da-Silva, Rodrigo Nunes; Lima-Junior, Josué da Costa; Fonseca, Bruna de Paula Fonseca e; Antas, Paulo Renato Zuquim; Baldez, Arlete; Storer, Fabio Luiz; Santos, Fátima; Banic, Dalma Maria; Oliveira-Ferreira, Joseli de

2014-04-01

Haematological and cytokine alterations in malaria are a broad and controversial subject in the literature. However, few studies have simultaneously evaluated various cytokines in a single patient group during the acute and convalescent phases of infection. The aim of this study was to sequentially characterise alterations in haematological patters and circulating plasma cytokine and chemokine levels in patients infected with Plasmodium vivax or Plasmodium falciparum from a Brazilian endemic area during the acute and convalescent phases of infection. During the acute phase, thrombocytopaenia, eosinopaenia, lymphopaenia and an increased number of band cells were observed in the majority of the patients. During the convalescent phase, the haematologic parameters returned to normal. During the acute phase, P. vivax and P. falciparum patients had significantly higher interleukin (IL)-6, IL-8, IL-17, interferon-γ, tumour necrosis factor (TNF)-α, macrophage inflammatory protein-1β and granulocyte-colony stimulating factor levels than controls and maintained high levels during the convalescent phase. IL-10 was detected at high concentrations during the acute phase, but returned to normal levels during the convalescent phase. Plasma IL-10 concentration was positively correlated with parasitaemia in P. vivax and P. falciparum-infected patients. The same was true for the TNF-α concentration in P. falciparum-infected patients. Finally, the haematological and cytokine profiles were similar between uncomplicated P. falciparum and P. vivax infections.

Human spleen and red blood cells

NASA Astrophysics Data System (ADS)

Pivkin, Igor; Peng, Zhangli; Karniadakis, George; Buffet, Pierre; Dao, Ming

2016-11-01

Spleen plays multiple roles in the human body. Among them is removal of old and altered red blood cells (RBCs), which is done by filtering cells through the endothelial slits, small micron-sized openings. There is currently no experimental technique available that allows us to observe RBC passage through the slits. It was previously noticed that people without a spleen have less deformable red blood cells, indicating that the spleen may play a role in defining the size and shape of red blood cells. We used detailed RBC model implemented within the Dissipative Particle Dynamics (DPD) simulation framework to study the filter function of the spleen. Our results demonstrate that spleen indeed plays major role in defining the size and shape of the healthy human red blood cells.

High prevalence of asymptomatic Plasmodium falciparum infection in Gabonese adults.

PubMed

Dal-Bianco, Matthias P; Köster, Kai B; Kombila, Ulrich D; Kun, Jürgen F J; Grobusch, Martin P; Ngoma, Ghyslain Mombo; Matsiegui, Pierre B; Supan, Christian; Salazar, Carmen L Ospina; Missinou, Michel A; Issifou, Saadou; Lell, Bertrand; Kremsner, Peter

2007-11-01

Plasmodium falciparum, the most common malarial parasite in sub-Saharan Africa, accounts for a high number of deaths in children less than five years of age. In malaria-endemic countries with stable transmission, semi-immunity is usually acquired after childhood. For adults, severe malaria is rare. Infected adults have either uncomplicated malaria or asymptomatic parasitemia. During a period of one year, we screened 497 afebrile males to investigate the prevalence of asymptomatic P. falciparum parasitemia in villages near Lambaréné, Gabon by use of three different methods. A total of 52% of the individuals had parasites detected by a subtelomeric variable open reading frame polymerase chain reaction (stevor-PCR), 27% of the rapid diagnostic test results were positive, and 12% of the thick blood smears with low parasitemias had P. falciparum. Most positive cases were only detected by the stevor-PCR. Asymptomatic P. falciparum parasitemia in adults living in a malaria-endemic country is frequent.

A pilot randomised trial of induced blood-stage Plasmodium falciparum infections in healthy volunteers for testing efficacy of new antimalarial drugs.

PubMed

McCarthy, James S; Sekuloski, Silvana; Griffin, Paul M; Elliott, Suzanne; Douglas, Nanette; Peatey, Chris; Rockett, Rebecca; O'Rourke, Peter; Marquart, Louise; Hermsen, Cornelius; Duparc, Stephan; Möhrle, Jörg; Trenholme, Katharine R; Humberstone, Andrew J

2011-01-01

Critical to the development of new drugs for treatment of malaria is the capacity to safely evaluate their activity in human subjects. The approach that has been most commonly used is testing in subjects with natural malaria infection, a methodology that may expose symptomatic subjects to the risk of ineffective treatment. Here we describe the development and pilot testing of a system to undertake experimental infection using blood stage Plasmodium falciparum parasites (BSP). The objectives of the study were to assess the feasibility and safety of induced BSP infection as a method for assessment of efficacy of new drug candidates for the treatment of P. falciparum infection. A prospective, unblinded, Phase IIa trial was undertaken in 19 healthy, malaria-naïve, male adult volunteers who were infected with BSP and followed with careful clinical and laboratory observation, including a sensitive, quantitative malaria PCR assay. Volunteers were randomly allocated to treatment with either of two licensed antimalarial drug combinations, artemether-lumefantrine (A/L) or atovaquone-proguanil (A/P). In the first cohort (n = 6) where volunteers received ∼360 BSP, none reached the target parasitemia of 1,000 before the day designated for antimalarial treatment (day 6). In the second and third cohorts, 13 volunteers received 1,800 BSP, with all reaching the target parasitemia before receiving treatment (A/L, n = 6; A/P, n = 7) The study demonstrated safety in the 19 volunteers tested, and a significant difference in the clearance kinetics of parasitemia between the drugs in the 13 evaluable subjects, with mean parasite reduction ratios of 759 for A/L and 17 for A/P (95% CI 120-4786 and 7-40 respectively; p<0.01). This system offers a flexible and safe approach to testing the in vivo activity of novel antimalarials. ClinicalTrials.gov NCT01055002.

No impact of strongylid infections on the detection of Plasmodium spp. in faeces of western lowland gorillas and eastern chimpanzees.

PubMed

Mapua, Mwanahamisi I; Pafčo, Barbora; Burgunder, Jade; Profousová-Pšenková, Ilona; Todd, Angelique; Hashimoto, Chie; Qablan, Moneeb A; Modrý, David; Petrželková, Klára J

2017-04-26

Although a high genetic diversity of Plasmodium spp. circulating in great apes has been revealed recently due to non-invasive methods enabling detection in faecal samples, little is known about the actual mechanisms underlying the presence of Plasmodium DNA in faeces. Great apes are commonly infected by strongylid nematodes, including hookworms, which cause intestinal bleeding. The impact of strongylid infections on the detection of Plasmodium DNA in faeces was assessed in wild, western, lowland gorillas from Dzanga Sangha Protected Areas, Central African Republic and eastern chimpanzees from Kalinzu Forest Reserve, Uganda. Fifty-one faecal samples from 22 habituated gorillas and 74 samples from 15 habituated chimpanzees were analysed using Cytochrome-b PCR assay and coprological methods. Overall, 26.4% of the analysed samples were positive for both Plasmodium spp. and strongylids. However, the results showed no significant impact of intensity of infections of strongylids on detection of Plasmodium DNA in gorilla and chimpanzee faeces. Bleeding caused by strongylid nematode Necator spp. cannot explain the presence of Plasmodium DNA in ape faeces.

Effect of chloroquine on gene expression of Plasmodium yoelii nigeriensis during its sporogonic development in the mosquito vector

PubMed Central

Silveira, Henrique; Ramos, Susana; Abrantes, Patrícia; Lopes, Luís Filipe; do Rosario, Virgílio E; Abrahamsen, Mitchell S

2007-01-01

Background The anti-malarial chloroquine can modulate the outcome of infection during the Plasmodium sporogonic development, interfering with Plasmodium gene expression and subsequently, with transmission. The present study sets to identify Plasmodium genes that might be regulated by chloroquine in the mosquito vector. Methods Differential display RT-PCR (DDRT-PCR) was used to identify genes expressed during the sporogonic cycle that are regulated by exposure to chloroquine. Anopheles stephensi mosquitoes were fed on Plasmodium yoelii nigeriensis-infected mice. Three days post-infection, mosquitoes were fed a non-infectious blood meal from mice treated orally with 50 mg/kg chloroquine. Two differentially expressed Plasmodium transcripts (Pyn_chl091 and Pyn_chl055) were further characterized by DNA sequencing and real-time PCR analysis. Results Both transcripts were represented in Plasmodium EST databases, but displayed no homology with any known genes. Pyn_chl091 was upregulated by day 18 post infection when the mosquito had a second blood meal. However, when the effect of chloroquine on that transcript was investigated during the erythrocytic cycle, no significant differences were observed. Although slightly upregulated by chloroquine exposure the expression of Pyn_chl055 was more affected by development, increasing towards the end of the sporogonic cycle. Transcript abundance of Pyn_chl055 was reduced when erythrocytic stages were treated with chloroquine. Conclusion Chloroquine increased parasite load in mosquito salivary glands and interferes with the expression of at least two Plasmodium genes. The transcripts identified contain putative signal peptides and transmembrane domains suggesting that these proteins, due to their location, are targets of chloroquine (not as an antimalarial) probably through cell trafficking and recycling. PMID:17605769

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

PubMed

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

2012-06-01

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

In vivo approaches reveal a key role for DCs in CD4+ T cell activation and parasite clearance during the acute phase of experimental blood-stage malaria.

PubMed

Borges da Silva, Henrique; Fonseca, Raíssa; Cassado, Alexandra Dos Anjos; Machado de Salles, Érika; de Menezes, Maria Nogueira; Langhorne, Jean; Perez, Katia Regina; Cuccovia, Iolanda Midea; Ryffel, Bernhard; Barreto, Vasco M; Marinho, Cláudio Romero Farias; Boscardin, Silvia Beatriz; Álvarez, José Maria; D'Império-Lima, Maria Regina; Tadokoro, Carlos Eduardo

2015-02-01

Dendritic cells (DCs) are phagocytes that are highly specialized for antigen presentation. Heterogeneous populations of macrophages and DCs form a phagocyte network inside the red pulp (RP) of the spleen, which is a major site for the control of blood-borne infections such as malaria. However, the dynamics of splenic DCs during Plasmodium infections are poorly understood, limiting our knowledge regarding their protective role in malaria. Here, we used in vivo experimental approaches that enabled us to deplete or visualize DCs in order to clarify these issues. To elucidate the roles of DCs and marginal zone macrophages in the protection against blood-stage malaria, we infected DTx (diphtheria toxin)-treated C57BL/6.CD11c-DTR mice, as well as C57BL/6 mice treated with low doses of clodronate liposomes (ClLip), with Plasmodium chabaudi AS (Pc) parasites. The first evidence suggesting that DCs could contribute directly to parasite clearance was an early effect of the DTx treatment, but not of the ClLip treatment, in parasitemia control. DCs were also required for CD4+ T cell responses during infection. The phagocytosis of infected red blood cells (iRBCs) by splenic DCs was analyzed by confocal intravital microscopy, as well as by flow cytometry and immunofluorescence, at three distinct phases of Pc malaria: at the first encounter, at pre-crisis concomitant with parasitemia growth and at crisis when the parasitemia decline coincides with spleen closure. In vivo and ex vivo imaging of the spleen revealed that DCs actively phagocytize iRBCs and interact with CD4+ T cells both in T cell-rich areas and in the RP. Subcapsular RP DCs were highly efficient in the recognition and capture of iRBCs during pre-crisis, while complete DC maturation was only achieved during crisis. These findings indicate that, beyond their classical role in antigen presentation, DCs also contribute to the direct elimination of iRBCs during acute Plasmodium infection.

In Vivo Approaches Reveal a Key Role for DCs in CD4+ T Cell Activation and Parasite Clearance during the Acute Phase of Experimental Blood-Stage Malaria

PubMed Central

Borges da Silva, Henrique; Fonseca, Raíssa; Cassado, Alexandra dos Anjos; Machado de Salles, Érika; de Menezes, Maria Nogueira; Langhorne, Jean; Perez, Katia Regina; Cuccovia, Iolanda Midea; Ryffel, Bernhard; Barreto, Vasco M.; Marinho, Cláudio Romero Farias; Boscardin, Silvia Beatriz; Álvarez, José Maria; D’Império-Lima, Maria Regina; Tadokoro, Carlos Eduardo

2015-01-01

Dendritic cells (DCs) are phagocytes that are highly specialized for antigen presentation. Heterogeneous populations of macrophages and DCs form a phagocyte network inside the red pulp (RP) of the spleen, which is a major site for the control of blood-borne infections such as malaria. However, the dynamics of splenic DCs during Plasmodium infections are poorly understood, limiting our knowledge regarding their protective role in malaria. Here, we used in vivo experimental approaches that enabled us to deplete or visualize DCs in order to clarify these issues. To elucidate the roles of DCs and marginal zone macrophages in the protection against blood-stage malaria, we infected DTx (diphtheria toxin)-treated C57BL/6.CD11c-DTR mice, as well as C57BL/6 mice treated with low doses of clodronate liposomes (ClLip), with Plasmodium chabaudi AS (Pc) parasites. The first evidence suggesting that DCs could contribute directly to parasite clearance was an early effect of the DTx treatment, but not of the ClLip treatment, in parasitemia control. DCs were also required for CD4+ T cell responses during infection. The phagocytosis of infected red blood cells (iRBCs) by splenic DCs was analyzed by confocal intravital microscopy, as well as by flow cytometry and immunofluorescence, at three distinct phases of Pc malaria: at the first encounter, at pre-crisis concomitant with parasitemia growth and at crisis when the parasitemia decline coincides with spleen closure. In vivo and ex vivo imaging of the spleen revealed that DCs actively phagocytize iRBCs and interact with CD4+ T cells both in T cell-rich areas and in the RP. Subcapsular RP DCs were highly efficient in the recognition and capture of iRBCs during pre-crisis, while complete DC maturation was only achieved during crisis. These findings indicate that, beyond their classical role in antigen presentation, DCs also contribute to the direct elimination of iRBCs during acute Plasmodium infection. PMID:25658925

Plasmodium berghei infection in pregnant rats: effects on antibody response and course of infection in offspring.

PubMed

Palmer, T T

1978-06-01

The effects of primary, patent Plasmodium berghei infection in Sprague-Dawley rats during pregnancy upon the course of infection and the humoral antibody response to malaria in their offspring were examined. Malaria specific antibody determined by an indirect fluorescent antibody test correlated well with the parasitologic profiles of each experimental group. Utilization of foster mother groups indicated passive transfer of protective antibody through milk. Evidence for in utero sensitization by soluble malaria antigens was shown by an anamnestic-like antibody response during subsequent infection of offspring from infected mothers.

Leukoerythroblastosis in a Young Child with Severe Malaria and Superimposed Gram Negative Infection.

PubMed

Varo, Rosauro; Sitoe, Antonio; Cossa, Anelsio; Ordi, Jaume; Rozman, Maria; Bassat, Quique

2017-12-18

Leukoerythroblastosis, a non-specific and often short-lasting response of the bone marrow to different diseases such as malignancies or infections, is characterized by the presence in the peripheral blood of immature red and white cells. We present a case of leukoerythoblastosis occurring in a 24 months old Mozambican girl, in the context of a severe malaria episode and an associated urinary tract infection. Peripheral blood smear was used for diagnosis of malaria and leukoerythroblastosis. Enterobacter cloacae isolation and antibiotic susceptibility testing were performed by conventional microbiology. Peripheral blood smear was positive for Plasmodium falciparum and showed a leukoerythroblastosis with red cell anisopoikilocytosis and left shifted neutrophils. Urine culture confirmed the presence of a multi-resistant E. cloacae. Treatment of underlying conditions resolved the leukoerythroblastic reaction. Leukoerythroblastosis may be related to different infectious diseases and may also appear in the context of severe malaria. Bacterial superinfection needs to be investigated. © The Author(s) [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Blood parasites from California ducks and geese

USGS Publications Warehouse

Herman, C.M.

1951-01-01

Blood smears were procured from 1,011 geese and ducks of 19 species from various locations in California. Parasites were found in 28 individuals. The parasites observed included Haemoproteus hermani, Leucocytozoon simondi, microfilaria, Plasmodium relictum (=P. biziurae), and Plasmodium sp. with elongate gametocytes. This is the first report of a natural infection with a Plasmodium in North American wild ducks.

Parasite infections in nestling red-shouldered hawks (Buteo lineatus) in northeast Wisconsin.

PubMed

King, Janet C; Dubay, Shelli A; Huspeni, Todd C; VanLanen, Andrew R; Gerhold, Richard W

2010-06-01

Red-shouldered hawks (Buteo lineatus) are threatened in Wisconsin and long-term data suggest that nest productivity is low in the state for unknown reasons. Our objective was to determine whether red-shouldered hawks in northeast Wisconsin were infected with parasites that could contribute to low nest productivity. We examined nestlings for the presence of Trichomonas gallinae, Protocalliphora avium, and blood parasites in June 2006 and 2007. We did not detect T. gallinae in throat swabs taken from 24 nestlings in 2007. Ear canals of nestlings were parasitized by P. avium larvae in 10 of 11 (91%) nests and in 22 of 24 (92%) nestlings. Larvae were found in higher intensity in 1 ear relative to the other. Leucocytozoon toddi was present in 90.5% (38/42) of the nestlings. At least 1 bird in each nest was infected. Intensity of L. toddi averaged 48.6 +/- 58.3 infected cells per 2,000 erythrocytes (2.4 +/- 2.9%). No other blood parasites were identified.

21 CFR 660.30 - Reagent Red Blood Cells.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Reagent Red Blood Cells. 660.30 Section 660.30 Food... ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition. The proper name of the product shall be Reagent Red...

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

Antibodies elicited during natural infection in a predominantly Plasmodium falciparum transmission area cross-react with sexual stage-specific antigen in P. vivax.

PubMed

Bansal, Geetha P; Vengesai, Arthur; Cao, Yi; Mduluza, Takafira; Kumar, Nirbhay

2017-06-01

Infections caused by Plasmodium falciparum and P. vivax account for more than 90% of global malaria burden. Exposure to malaria parasite elicits immune responses during natural infection and it is generally believed that the immunity is not only stage specific but also species specific. However, partial genomic similarity for various antigens in different Plasmodium spp. raises the possibility of immunological cross-reactivity at the level of specific antigens. Serum samples collected from children who were permanent residents of a P. falciparum transmission area in Zimbabwe were screened for antibody reactivity against Pfs48/45, a P. falciparum gametocyte antigen and Pvs48/45, a P. vivax homolog of Pfs48/45 using ELISA. Western blotting was used to further confirm identity of the specific antibody reactivity to the Pfs48/45 and Pvs48/45 proteins. Pan Plasmodium PCR and nested PCR were used to confirm infection with the Plasmodium species. Twenty-seven percent (49/181) of the participants were found to be sero-positive for Pfs48/45 and 73% (n=36) of these Pfs48/45 positive sera also showed reactivity with Pvs48/45. Immune cross-reactivity revealed by ELISA was also confirmed by Western blot analysis using a panel of randomly selected 23 Pfs48/45 and Pvs48/45 ELISA positive samples. Nested PCR analysis of 27 blood samples randomly selected from the 36 that showed positive ELISA reactivity to both Pfs48/45 and Pvs48/45 antigens confirmed infection with P. falciparum and generalized absence of P. vivax except for a single sample which revealed PCR positivity for both P. vivax and P. falciparum. Our studies with sera samples from a predominantly P. falciparum transmission area in Zimbabwe suggest immunological cross-reactivity with Pvs48/45, thus raising the possibility of partial species cross-reactive immunity and possible cross-boosting of immunity during co-infection with P. falciparum and P. vivax. Copyright © 2017 Elsevier B.V. All rights reserved.

Susceptibility to Plasmodium yoelii Preerythrocytic Infection in BALB/c Substrains Is Determined at the Point of Hepatocyte Invasion

PubMed Central

Kaushansky, Alexis; Austin, Laura S.; Mikolajczak, Sebastian A.; Lo, Fang Y.; Miller, Jessica L.; Douglass, Alyse N.; Arang, Nadia; Vaughan, Ashley M.; Gardner, Malcolm J.

2014-01-01

After transmission by Anopheles mosquitoes, Plasmodium sporozoites travel to the liver, infect hepatocytes, and rapidly develop as intrahepatocytic liver stages (LS). Rodent models of malaria exhibit large differences in the magnitude of liver infection, both between parasite species and between strains of mice. This has been mainly attributed to differences in innate immune responses and parasite infectivity. Here, we report that BALB/cByJ mice are more susceptible to Plasmodium yoelii preerythrocytic infection than BALB/cJ mice. This difference occurs at the level of early hepatocyte infection, but expression levels of reported host factors that are involved in infection do not correlate with susceptibility. Interestingly, BALB/cByJ hepatocytes are more frequently polyploid; thus, their susceptibility converges on the previously observed preference of sporozoites to infect polyploid hepatocytes. Gene expression analysis demonstrates hepatocyte-specific differences in mRNA abundance for numerous genes between BALB/cByJ and BALB/cJ mice, some of which encode hepatocyte surface molecules. These data suggest that a yet-unknown receptor for sporozoite infection, present at elevated levels on BALB/cByJ hepatocytes and also polyploid hepatocytes, might facilitate Plasmodium liver infection. PMID:25312960

Red blood cell vesiculation in hereditary hemolytic anemia

PubMed Central

Alaarg, Amr; Schiffelers, Raymond M.; van Solinge, Wouter W.; van Wijk, Richard

2013-01-01

Hereditary hemolytic anemia encompasses a heterogeneous group of anemias characterized by decreased red blood cell survival because of inherited membrane, enzyme, or hemoglobin disorders. Affected red blood cells are more fragile, less deformable, and more susceptible to shear stress and oxidative damage, and show increased vesiculation. Red blood cells, as essentially all cells, constitutively release phospholipid extracellular vesicles in vivo and in vitro in a process known as vesiculation. These extracellular vesicles comprise a heterogeneous group of vesicles of different sizes and intracellular origins. They are described in literature as exosomes if they originate from multi-vesicular bodies, or as microvesicles when formed by a one-step budding process directly from the plasma membrane. Extracellular vesicles contain a multitude of bioactive molecules that are implicated in intercellular communication and in different biological and pathophysiological processes. Mature red blood cells release in principle only microvesicles. In hereditary hemolytic anemias, the underlying molecular defect affects and determines red blood cell vesiculation, resulting in shedding microvesicles of different compositions and concentrations. Despite extensive research into red blood cell biochemistry and physiology, little is known about red cell deformability and vesiculation in hereditary hemolytic anemias, and the associated pathophysiological role is incompletely assessed. In this review, we discuss recent progress in understanding extracellular vesicles biology, with focus on red blood cell vesiculation. Also, we review recent scientific findings on the molecular defects of hereditary hemolytic anemias, and their correlation with red blood cell deformability and vesiculation. Integrating bio-analytical findings on abnormalities of red blood cells and their microvesicles will be critical for a better understanding of the pathophysiology of hereditary hemolytic anemias. PMID

Multiple lineages of Avian malaria parasites (Plasmodium) in the Galapagos Islands and evidence for arrival via migratory birds.

PubMed

Levin, I I; Zwiers, P; Deem, S L; Geest, E A; Higashiguchi, J M; Iezhova, T A; Jiménez-Uzcátegui, G; Kim, D H; Morton, J P; Perlut, N G; Renfrew, R B; Sari, E H R; Valkiunas, G; Parker, P G

2013-12-01

Haemosporidian parasites in the genus Plasmodium were recently detected through molecular screening in the Galapagos Penguin (Spheniscus mendiculus). We summarized results of an archipelago-wide screen of 3726 endemic birds representing 22 species for Plasmodium spp. through a combination of molecular and microscopy techniques. Three additional Plasmodium lineages were present in Galapagos. Lineage A-infected penguins, Yellow Warblers (Setophaga petechia aureola), and one Medium Ground Finch (Geospiza fortis) and was detected at multiple sites in multiple years [corrected]. The other 3 lineages were each detected at one site and at one time; apparently, they were transient infections of parasites not established on the archipelago. No gametocytes were found in blood smears of infected individuals; thus, endemic Galapagos birds may be dead-end hosts for these Plasmodium lineages. Determining when and how parasites and pathogens arrive in Galapagos is key to developing conservation strategies to prevent and mitigate the effects of introduced diseases. To assess the potential for Plasmodium parasites to arrive via migratory birds, we analyzed blood samples from 438 North American breeding Bobolinks (Dolichonyx oryzivorus), the only songbird that regularly migrates through Galapagos. Two of the ephemeral Plasmodium lineages (B and C) found in Galapagos birds matched parasite sequences from Bobolinks. Although this is not confirmation that Bobolinks are responsible for introducing these lineages, evidence points to higher potential arrival rates of avian pathogens than previously thought. Linajes Múltiples de Parásitos de Malaria Aviar (Plasmodium) en las Islas Galápagos y Evidencia de su Arribo por Medio de Aves Migratorias. © 2013 Society for Conservation Biology.

Innexin AGAP001476 Is Critical for Mediating Anti-Plasmodium Responses in Anopheles Mosquitoes

PubMed Central

Li, Michelle W. M.; Wang, Jiuling; Zhao, Yang O.; Fikrig, Erol

2014-01-01

The Toll and IMD pathways are known to be induced upon Plasmodium berghei and Plasmodium falciparum infection, respectively. It is unclear how Plasmodium or other pathogens in the blood meal and their invasion of the midgut epithelium would trigger the innate immune responses in immune cells, in particular hemocytes. Gap junctions, which can mediate both cell-to-cell and cell-to-extracellular communication, may participate in this signal transduction. This study examined whether innexins, gap junction proteins in insects, are involved in anti-Plasmodium responses in Anopheles gambiae. Inhibitor studies using carbenoxolone indicated that blocking innexons resulted in an increase in Plasmodium oocyst number and infection prevalence. This was accompanied by a decline in TEP1 levels in carbenoxolone-treated mosquitoes. Innexin AGAP001476 mRNA levels in midguts were induced during Plasmodium infection and a knockdown of AGAP001476, but not AGAP006241, caused an induction in oocyst number. Silencing AGAP001476 caused a concurrent increase in vitellogenin levels, a TEP1 inhibitor, in addition to a reduced level of TEP1-LRIM1-APL1C complex in hemolymph. Both vitellogenin and TEP1 are regulated by Cactus under the Toll pathway. Simultaneous knockdown of cactus and AGAP001476 failed to reverse the near refractoriness induced by the knockdown of cactus, suggesting that the AGAP001476-mediated anti-Plasmodium response is Cactus-dependent. These data demonstrate a critical role for innexin AGAP001476 in mediating innate immune responses against Plasmodium through Toll pathway in mosquitoes. PMID:25035430

Subinoculation as a technique in the diagnosis of avian plasmodium

USGS Publications Warehouse

Herman, C.M.; Knisley, J.O.; Snyder, E.L.

1966-01-01

In two successive years, 1964 and 1965, blood subinoculated from wild Canada geese, negative for Plasmodium by examination of peripheral blood smears, into 5-day-old domestic geese produced 60 % infection in the recipients. Prepatent and patent periods, as well as intensity of parasitemia showed much variation. Intramuscular inoculation produced the same prevalence as the intravenous route, but longer prepatent periods and less intensity of parasitemia.

[A fifth plasmodium that can cause malaria].

PubMed

Myrvang, Bjørn

2010-02-11

Since 2004, malaria with a "fifth" plasmodium, Plasmodium knowlesi (common in macaque monkeys), has been diagnosed in a number of people in Southeast Asia. This article gives a short overview of the epidemiology, clinical picture, diagnostics and treatment of P. knowlesi infection. The article is mainly based on articles published in international journals during the last five years. Most cases have been diagnosed in the Malaysian state Sarawak on the island of Borneo. The disease usually presents in the same way as other types of malaria, with the exception that fever spikes comes at 24-hour intervals. Microscopy findings resemble those for P. malariae in the early phase of the disease and many patients have been diagnosed wrongly. Without treatment a serious clinical picture may develop, blood findings may be as serious as for P. falciparum infection and death may occur. Chloroquine tablets are indicated in light infections, while parenteral therapy with artesunate or quinine is necessary in seriously affected patients. P. knowlesi infection has been reported among tourists in Malaysia. The risk of contracting P. knowlesi infection as well as other types of malaria is low in Malaysia and other regions where P knowlesi occurs.

Prevalence of selected viral infections among temporarily deferred donors who returned to donate blood: American Red Cross blood donor study.

PubMed

Zou, Shimian; Musavi, Fatemeh; Notari, Edward P; Fujii, Karen E; Dodd, Roger Y

2005-10-01

Health history questions are introduced into the predonation interview to identify blood donors believed to pose a higher risk of infectious diseases to recipients. This study assesses the current impact of some of those questions. Donor deferral and donation data were extracted from a research database of the American Red Cross. The prevalence of hepatitis B surface antigen or antibodies to human immunodeficiency virus, hepatitis C virus, or human T-lymphotropic virus was obtained for different groups of donors who were temporarily deferred in 2000 through 2001 and later returned to donate blood in 2000 through 2003. The results were compared with either first-time or repeat donors in 2000 through 2003, while controlling for differences in sex, age, and year of donation. Of donors temporarily deferred in 2000 through 2001 who had had no donation or deferral during the previous 2 years, only 22.08 percent subsequently returned to donate blood in 2000 through 2003. Donations from returning donors who had been deferred for potential infectious disease risk did not show a higher prevalence for any of the viral markers when those with no donation or deferral during the previous two years were compared with first-time donations, and those with prior donation were compared with repeat donations. Blood donors temporarily deferred in 2000 through 2001 for potential risk of viral infection who later returned to donate blood did not appear to pose a higher risk compared to first-time or repeat donors. The effectiveness of some of the currently used deferral questions in reducing viral risks warrants further study.

Avian Plasmodium in Culex and Ochlerotatus Mosquitoes from Southern Spain: Effects of Season and Host-Feeding Source on Parasite Dynamics

PubMed Central

Ferraguti, Martina; Martínez-de la Puente, Josué; Muñoz, Joaquín; Roiz, David; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

2013-01-01

Haemosporidians, a group of vector-borne parasites that include Plasmodium, infect vertebrates including birds. Although mosquitoes are crucial elements in the transmission of avian malaria parasites, little is known of their ecology as vectors. We examined the presence of Plasmodium and Haemoproteus lineages in five mosquito species belonging to the genera Culex and Ochlerotatus to test for the effect of vector species, season and host-feeding source on the transmission dynamics of these pathogens. We analyzed 166 blood-fed individually and 5,579 unfed mosquitoes (grouped in 197 pools) from a locality in southern Spain. In all, 15 Plasmodium and two Haemoproteus lineages were identified on the basis of a fragment of 478 bp of the mitochondrial cytochrome b gene. Infection prevalence of blood parasites in unfed mosquitoes varied between species (range: 0–3.2%) and seasons. The feeding source was identified in 91 mosquitoes where 78% were identified as bird. We found that i) several Plasmodium lineages are shared among different Culex species and one Plasmodium lineage is shared between Culex and Ochlerotatus genera; ii) mosquitoes harboured Haemoproteus parasites; iii) pools of unfed females of mostly ornithophilic Culex species had a higher Plasmodium prevalence than the only mammophylic Culex species studied. However, the mammophylic Ochlerotatus caspius had in pool samples the greatest Plasmodium prevalence. This relative high prevalence may be determined by inter-specific differences in vector survival, susceptibility to infection but also the possibility that this species feeds on birds more frequently than previously thought. Finally, iv) infection rate of mosquitoes varies between seasons and reaches its maximum prevalence during autumn and minimum prevalence in spring. PMID:23823127

Persistence of Plasmodium falciparum parasites in infected pregnant Mozambican women after delivery.

PubMed

Serra-Casas, Elisa; Menéndez, Clara; Dobaño, Carlota; Bardají, Azucena; Quintó, Llorenç; Quintó, Llorençc; Ordi, Jaume; Sigauque, Betuel; Cisteró, Pau; Mandomando, Inacio; Alonso, Pedro L; Mayor, Alfredo

2011-01-01

Pregnant women are susceptible to Plasmodium falciparum parasites that sequester in the placenta. The massive accumulation of infected erythrocytes in the placenta has been suggested to trigger the deleterious effects of malaria in pregnant women and their offspring. The risk of malaria is also high during the postpartum period, although mechanisms underlying this susceptibility are not known. Here, we aimed to identify host factors contributing to the risk of postpartum infections and to determine the origin of postpartum parasites by comparing their genotypes with those present at the time of delivery. To address this, blood samples were collected at delivery (n = 402) and postpartum (n = 354) from Mozambican women enrolled in a trial of intermittent preventive treatment in pregnancy (IPTp). P. falciparum was detected by real-time quantitative PCR (qPCR), and the parasite merozoite surface protein 1 (msp-1) and msp-2 genes were genotyped. Fifty-seven out of 354 (16%) women were infected postpartum as assessed by qPCR, whereas prevalence by optical microscopy was only 4%. Risk of postpartum infection was lower in older women (odds ratio [OR] = 0.34, 95% confidence interval [CI] = 0.15 to 0.81) and higher in women with a placental infection at delivery (OR = 4.20, 95% CI = 2.19 to 8.08). Among 24 women with matched infections, 12 (50%) were infected postpartum with at least one parasite strain that was also present in their placentas. These results suggest that parasites infecting pregnant women persist after delivery and increase the risk of malaria during the postpartum period. Interventions that reduce malaria during pregnancy may translate into a lower risk of postpartum infection.

Analysis of Plasmodium falciparum diversity in natural infections by deep sequencing

PubMed Central

Manske, Magnus; Miotto, Olivo; Campino, Susana; Auburn, Sarah; Almagro-Garcia, Jacob; Maslen, Gareth; O’Brien, Jack; Djimde, Abdoulaye; Doumbo, Ogobara; Zongo, Issaka; Ouedraogo, Jean-Bosco; Michon, Pascal; Mueller, Ivo; Siba, Peter; Nzila, Alexis; Borrmann, Steffen; Kiara, Steven M.; Marsh, Kevin; Jiang, Hongying; Su, Xin-Zhuan; Amaratunga, Chanaki; Fairhurst, Rick; Socheat, Duong; Nosten, Francois; Imwong, Mallika; White, Nicholas J.; Sanders, Mandy; Anastasi, Elisa; Alcock, Dan; Drury, Eleanor; Oyola, Samuel; Quail, Michael A.; Turner, Daniel J.; Rubio, Valentin Ruano; Jyothi, Dushyanth; Amenga-Etego, Lucas; Hubbart, Christina; Jeffreys, Anna; Rowlands, Kate; Sutherland, Colin; Roper, Cally; Mangano, Valentina; Modiano, David; Tan, John C.; Ferdig, Michael T.; Amambua-Ngwa, Alfred; Conway, David J.; Takala-Harrison, Shannon; Plowe, Christopher V.; Rayner, Julian C.; Rockett, Kirk A.; Clark, Taane G.; Newbold, Chris I.; Berriman, Matthew; MacInnis, Bronwyn; Kwiatkowski, Dominic P.

2013-01-01

Malaria elimination strategies require surveillance of the parasite population for genetic changes that demand a public health response, such as new forms of drug resistance. 1,2 Here we describe methods for large-scale analysis of genetic variation in Plasmodium falciparum by deep sequencing of parasite DNA obtained from the blood of patients with malaria, either directly or after short term culture. Analysis of 86,158 exonic SNPs that passed genotyping quality control in 227 samples from Africa, Asia and Oceania provides genome-wide estimates of allele frequency distribution, population structure and linkage disequilibrium. By comparing the genetic diversity of individual infections with that of the local parasite population, we derive a metric of within-host diversity that is related to the level of inbreeding in the population. An open-access web application has been established for exploration of regional differences in allele frequency and of highly differentiated loci in the P. falciparum genome. PMID:22722859

21 CFR 660.30 - Reagent Red Blood Cells.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Reagent Red Blood Cells. 660.30 Section 660.30...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition. The proper name of the product shall be...

21 CFR 660.30 - Reagent Red Blood Cells.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Reagent Red Blood Cells. 660.30 Section 660.30...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition. The proper name of the product shall be...

21 CFR 660.30 - Reagent Red Blood Cells.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Reagent Red Blood Cells. 660.30 Section 660.30...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition. The proper name of the product shall be...

21 CFR 660.30 - Reagent Red Blood Cells.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Reagent Red Blood Cells. 660.30 Section 660.30...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition. The proper name of the product shall be...

Susceptibility to Plasmodium yoelii preerythrocytic infection in BALB/c substrains is determined at the point of hepatocyte invasion.

PubMed

Kaushansky, Alexis; Austin, Laura S; Mikolajczak, Sebastian A; Lo, Fang Y; Miller, Jessica L; Douglass, Alyse N; Arang, Nadia; Vaughan, Ashley M; Gardner, Malcolm J; Kappe, Stefan H I

2015-01-01

After transmission by Anopheles mosquitoes, Plasmodium sporozoites travel to the liver, infect hepatocytes, and rapidly develop as intrahepatocytic liver stages (LS). Rodent models of malaria exhibit large differences in the magnitude of liver infection, both between parasite species and between strains of mice. This has been mainly attributed to differences in innate immune responses and parasite infectivity. Here, we report that BALB/cByJ mice are more susceptible to Plasmodium yoelii preerythrocytic infection than BALB/cJ mice. This difference occurs at the level of early hepatocyte infection, but expression levels of reported host factors that are involved in infection do not correlate with susceptibility. Interestingly, BALB/cByJ hepatocytes are more frequently polyploid; thus, their susceptibility converges on the previously observed preference of sporozoites to infect polyploid hepatocytes. Gene expression analysis demonstrates hepatocyte-specific differences in mRNA abundance for numerous genes between BALB/cByJ and BALB/cJ mice, some of which encode hepatocyte surface molecules. These data suggest that a yet-unknown receptor for sporozoite infection, present at elevated levels on BALB/cByJ hepatocytes and also polyploid hepatocytes, might facilitate Plasmodium liver infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

DPD simulation on the dynamics of a healthy and infected red blood cell in flow through a constricted channel

NASA Astrophysics Data System (ADS)

Hoque, Sazid Zamal; Anand, D. Vijay; Patnaik, B. S. V.

2017-11-01

The state of the red blood cell (either healthy or infected RBC) will influence its deformation dynamics. Since the pathological condition related to RBC, primarily originates from a single cell infection, therefore, it is important to relate the deformation dynamics to the mechanical properties (such as, bending rigidity and membrane elasticity). In the present study, numerical simulation of a healthy and malaria infected RBC in a constricted channel is analyzed. The flow simulations are carried out using finite sized dissipative particle dynamics (FDPD) method in conjunction with a discrete model that represents the membrane of the RBC. The numerical equivalent of optical tweezers test is validated against the experimental studies. Two different types of constrictions, viz., a converging-diverging type tapered channel and a stenosed microchannel are considered for the simulation. The effect of degree of constriction and the flow rate effect on the RBC is investigated. It was observed that, as the flow rate decreases, the infected RBC completely blocks the micro vessel. The transit time for infected cell drastically increases compared to healthy RBC. Our simulations indicate that, there is a critical flow rate below which infected RBC cannot pass through the micro capillary.

Co-endemicity of Plasmodium falciparum and Intestinal Helminths Infection in School Age Children in Rural Communities of Kwara State Nigeria

PubMed Central

Adedoja, Ayodele; Tijani, Bukola Deborah; Akanbi, Ajibola A.; Ojurongbe, Taiwo A.; Adeyeba, Oluwaseyi A.; Ojurongbe, Olusola

2015-01-01

Background Malaria and intestinal helminths co-infection are major public health problems particularly among school age children in Nigeria. However the magnitude and possible interactions of these infections remain poorly understood. This study determined the prevalence, impact and possible interaction of Plasmodium falciparum and intestinal helminths co-infection among school children in rural communities of Kwara State, Nigeria. Methods Blood, urine and stool samples were collected from 1017 primary school pupils of ages 4–15 years. Stool samples were processed using both Kato-Katz and formol-ether concentration techniques and microscopically examined for intestinal helminths infection. Urine samples were analyzed using sedimentation method for Schistosoma haematobium. Plasmodium falciparum was confirmed by microscopy using thick and thin blood films methods and packed cell volume (PCV) was determined using hematocrit reader. Univariate analysis and chi-square statistical tests were used to analyze the data. Results Overall, 61.2% of all school children had at least an infection of either P. falciparum, S. haematobium, or intestinal helminth. S. haematobium accounted for the largest proportion (44.4%) of a single infection followed by P. falciparum (20.6%). The prevalence of malaria and helminth co-infection in the study was 14.4%. Four species of intestinal helminths were recovered from the stool samples and these were hookworm (22.5%), Hymenolepis species (9.8%), Schistosoma mansoni (2.9%) and Enterobius vermicularis (0.6%). The mean densities of P. falciparum in children co-infected with S. haematobium and hookworm were higher compared to those infected with P. falciparum only though not statistically significant (p = 0.062). The age distribution of both S. haematobium (p = 0.049) and hookworm (p = 0.034) infected children were statistically significant with the older age group (10–15 years) recording the highest prevalence of 47.2% and 25% respectively

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

PubMed

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

1986-05-29

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

Resistance of infection by Plasmodium vivax to chloroquine in Bolivia.

PubMed

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

2015-07-01

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

Macrophage Migration Inhibitory Factor Release by Macrophages after Ingestion of Plasmodium chabaudi-Infected Erythrocytes: Possible Role in the Pathogenesis of Malarial Anemia

PubMed Central

Martiney, James A.; Sherry, Barbara; Metz, Christine N.; Espinoza, Marisol; Ferrer, Angel S.; Calandra, Thierry; Broxmeyer, Hal E.; Bucala, Richard

2000-01-01

Human falciparum malaria, caused by Plasmodium falciparum infection, results in 1 to 2 million deaths per year, mostly children under the age of 5 years. The two main causes of death are severe anemia and cerebral malaria. Malarial anemia is characterized by parasite red blood cell (RBC) destruction and suppression of erythropoiesis (the mechanism of which is unknown) in the presence of a robust host erythropoietin response. The production of a host-derived erythropoiesis inhibitor in response to parasite products has been implicated in the pathogenesis of malarial anemia. The identity of this putative host factor is unknown, but antibody neutralization studies have ruled out interleukin-1β, tumor necrosis factor alpha, and gamma interferon while injection of interleukin-12 protects susceptible mice against lethal P. chabaudi infection. In this study, we report that ingestion of P. chabaudi-infected erythrocytes or malarial pigment (hemozoin) induces the release of macrophage migration inhibitory factor (MIF) from macrophages. MIF, a proinflammatory mediator and counter-regulator of glucocorticoid action, inhibits erythroid (BFU-E), multipotential (CFU-GEMM), and granulocyte-macrophage (CFU-GM) progenitor-derived colony formation. MIF was detected in the sera of P. chabaudi-infected BALB/c mice, and circulating levels correlated with disease severity. Liver MIF immunoreactivity increased concomitant with extensive pigment and parasitized RBC deposition. Finally, MIF was elevated three- to fourfold in the spleen and bone marrow of P. chabaudi-infected mice with active disease, as compared to early disease, or of uninfected controls. In summary, the present results suggest that MIF may be a host-derived factor involved in the pathophysiology of malaria anemia. PMID:10722628

Do blood parasites infect Magellanic penguins (Spheniscus magellanicus) in the wild? Prospective investigation and climatogeographic considerations.

PubMed

Vanstreels, Ralph Eric Thijl; Uhart, Marcela; Rago, Virginia; Hurtado, Renata; Epiphanio, Sabrina; Catão-Dias, José Luiz

2017-04-01

Magellanic penguins (Spheniscus magellanicus) are native to Argentina, Chile and the Falkland Islands. Magellanic penguins are highly susceptible to blood parasites such as the mosquito-borne Plasmodium spp., which have been documented causing high morbidity and mortality in zoos and rehabilitation centres. However, to date no blood parasites have been detected in wild Magellanic penguins, and it is not clear whether this is reflective of their true absence or is instead related to an insufficiency in sampling effort or a failure of the diagnostic methods. We examined blood smears of 284 Magellanic penguins from the Argentinean coast and tested their blood samples with nested polymerase chain reaction tests targeting Haemoproteus, Plasmodium, Leucocytozoon and Babesia. No blood parasites were detected. Analysing the sampling effort of previous studies and the climatogeography of the region, we found there is strong basis to conclude that haemosporidians do not infect wild Magellanic penguins on the Argentinean coast. However, at present it is not possible to determine whether such parasites occur on the Chilean coast and at the Falkland Islands. Furthermore, it is troubling that the northward distribution expansion of Magellanic penguins and the poleward distribution shift of vectors may lead to novel opportunities for the transmission of blood parasites.

Plasmodium berghei ANKA (PbA) infection of C57BL/6J mice: a model of severe malaria.

PubMed

de Oca, Marcela Montes; Engwerda, Christian; Haque, Ashraful

2013-01-01

The term "severe malaria" refers to a wide spectrum of syndromes in Plasmodium-infected humans including cerebral malaria (CM), respiratory distress, severe anemia, liver dysfunction, and hypoglycemia. Mouse models have been employed to further our understanding of the pathology and immune responses that occur during Plasmodium infection. Evidence of brain, liver, lung, and spleen pathology, as well as anemia and tissue-sequestration of parasites, has been reported in various strains of inbred mice. While no single mouse model mimics all the various clinical manifestations of severe malaria in humans, here we describe a detailed protocol for Plasmodium berghei ANKA infection of C57BL/6J mice. For many years, this model has been referred to as "experimental cerebral malaria," but in fact recapitulates many of the symptoms and pathologies observed in most severe malaria syndromes.

The use of Aotus Trivirgatus and Macaca Mulatta as Tools for Studies on Prevention and Therapy of Infections with Plasmodium Falciparum and Plasmodium Vivax

DTIC Science & Technology

1976-08-13

INFECTIONS WITH PLASMODIUM FALCIPARUM AND PLASMODIUM VIVAX (U) FINAL PROGRESS REPORT ( PROJECT 2284-XXIX) For the Period I May 1975 to 30 April...IT» IOC mit settiM I’jtf Section ^ I» ’■■■■• BisTtmunM/MWUiiun cooa DiJÜ iWBU. UK/» FINAL PROGRESS REPORT ( PROJECT 2284-XXIX) S...quinolinemethanols pyridinemethanols I ’As in previous years, the activities of this Project were focused on development of: (a) agents fully effective

High rate of adaptation of mammalian proteins that interact with Plasmodium and related parasites

PubMed Central

Telis, Natalie; Petrov, Dmitri A.

2017-01-01

Plasmodium parasites, along with their Piroplasm relatives, have caused malaria-like illnesses in terrestrial mammals for millions of years. Several Plasmodium-protective alleles have recently evolved in human populations, but little is known about host adaptation to blood parasites over deeper evolutionary timescales. In this work, we analyze mammalian adaptation in ~500 Plasmodium- or Piroplasm- interacting proteins (PPIPs) manually curated from the scientific literature. We show that (i) PPIPs are enriched for both immune functions and pleiotropy with other pathogens, and (ii) the rate of adaptation across mammals is significantly elevated in PPIPs, compared to carefully matched control proteins. PPIPs with high pathogen pleiotropy show the strongest signatures of adaptation, but this pattern is fully explained by their immune enrichment. Several pieces of evidence suggest that blood parasites specifically have imposed selection on PPIPs. First, even non-immune PPIPs that lack interactions with other pathogens have adapted at twice the rate of matched controls. Second, PPIP adaptation is linked to high expression in the liver, a critical organ in the parasite life cycle. Finally, our detailed investigation of alpha-spectrin, a major red blood cell membrane protein, shows that domains with particularly high rates of adaptation are those known to interact specifically with P. falciparum. Overall, we show that host proteins that interact with Plasmodium and Piroplasm parasites have experienced elevated rates of adaptation across mammals, and provide evidence that some of this adaptation has likely been driven by blood parasites. PMID:28957326

Renal related disorders in concomitant Schistosoma haematobium-Plasmodium falciparum infection among children in a rural community of Nigeria.

PubMed

Morenikeji, Olajumoke A; Eleng, Ituna E; Atanda, Omotayo S; Oyeyemi, Oyetunde T

2016-01-01

Schistosomiasis and malaria are two common parasitic diseases that are co-endemic in resource-poor communities of sub-Saharan Africa. This study aims to assess the effects of single and concomitant Plasmodium falciparum and Schistosoma haematobium infections on two indicators of renal injury in school children in a rural community of Nigeria. A cross-sectional epidemiological survey was carried out on a total of 173 schoolchildren between ages 6 and 18 years (mean age 11.4±2.6 years). Urine and blood samples were collected by standard methods for concurrent microscopic diagnosis of S. haematobium and P. falciparum infections. Urinary blood (hematuria) and protein were determined using a urinalysis dipstick. The prevalence of single infections was 75.1% and 78.2% for S. haematobium and P. falciparum, respectively. A total of 57.1% individuals were infected with the two parasites. The prevalence of hematuria was significantly higher in the co-infection status (63.8%) than in single S. haematobium (52.2%) and P. falciparum (43.7%) infection statuses (p=0.04), while no significant variation was recorded in proteinuria in the three infection statuses (p=0.53). The proportion of children with renal injury associated with the co-infection of these parasites is very high, particularly in young children, who seem to have a higher prevalence of hematuria. Copyright © 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

A novel Pfs38 protein complex on the surface of Plasmodium falciparum blood-stage merozoites.

PubMed

Paul, Gourab; Deshmukh, Arunaditya; Kaur, Inderjeet; Rathore, Sumit; Dabral, Surbhi; Panda, Ashutosh; Singh, Susheel Kumar; Mohmmed, Asif; Theisen, Michael; Malhotra, Pawan

2017-02-16

The Plasmodium genome encodes for a number of 6-Cys proteins that contain a module of six cysteine residues forming three intramolecular disulphide bonds. These proteins have been well characterized at transmission as well as hepatic stages of the parasite life cycle. In the present study, a large complex of 6-Cys proteins: Pfs41, Pfs38 and Pfs12 and three other merozoite surface proteins: Glutamate-rich protein (GLURP), SERA5 and MSP-1 were identified on the Plasmodium falciparum merozoite surface. Recombinant 6-cys proteins i.e. Pfs38, Pfs12, Pfs41 as well as PfMSP-1 65 were expressed and purified using Escherichia coli expression system and antibodies were raised against each of these proteins. These antibodies were used to immunoprecipitate the native proteins and their associated partners from parasite lysate. ELISA, Far western, surface plasmon resonance and glycerol density gradient fractionation were carried out to confirm the respective interactions. Furthermore, erythrocyte binding assay with 6-cys proteins were undertaken to find out their possible role in host-parasite infection and seropositivity was assessed using Indian and Liberian sera. Immunoprecipitation of parasite-derived polypeptides, followed by LC-MS/MS analysis, identified a large Pfs38 complex comprising of 6-cys proteins: Pfs41, Pfs38, Pfs12 and other merozoite surface proteins: GLURP, SERA5 and MSP-1. The existence of such a complex was further corroborated by several protein-protein interaction tools, co-localization and co-sedimentation analysis. Pfs38 protein of Pfs38 complex binds to host red blood cells (RBCs) directly via glycophorin A as a receptor. Seroprevalence analysis showed that of the six antigens, prevalence varied from 40 to 99%, being generally highest for MSP-1 65 and GLURP proteins. Together the data show the presence of a large Pfs38 protein-associated complex on the parasite surface which is involved in RBC binding. These results highlight the complex molecular

A vacuolar iron-transporter homologue acts as a detoxifier in Plasmodium

PubMed Central

Slavic, Ksenija; Krishna, Sanjeev; Lahree, Aparajita; Bouyer, Guillaume; Hanson, Kirsten K.; Vera, Iset; Pittman, Jon K.; Staines, Henry M.; Mota, Maria M.

2016-01-01

Iron is an essential micronutrient but is also highly toxic. In yeast and plant cells, a key detoxifying mechanism involves iron sequestration into intracellular storage compartments, mediated by members of the vacuolar iron-transporter (VIT) family of proteins. Here we study the VIT homologue from the malaria parasites Plasmodium falciparum (PfVIT) and Plasmodium berghei (PbVIT). PfVIT-mediated iron transport in a yeast heterologous expression system is saturable (Km∼14.7 μM), and selective for Fe2+ over other divalent cations. PbVIT-deficient P. berghei lines (Pbvit−) show a reduction in parasite load in both liver and blood stages of infection in mice. Moreover, Pbvit− parasites have higher levels of labile iron in blood stages and are more sensitive to increased iron levels in liver stages, when compared with wild-type parasites. Our data are consistent with Plasmodium VITs playing a major role in iron detoxification and, thus, normal development of malaria parasites in their mammalian host. PMID:26786069

A vacuolar iron-transporter homologue acts as a detoxifier in Plasmodium.

PubMed

Slavic, Ksenija; Krishna, Sanjeev; Lahree, Aparajita; Bouyer, Guillaume; Hanson, Kirsten K; Vera, Iset; Pittman, Jon K; Staines, Henry M; Mota, Maria M

2016-01-20

Iron is an essential micronutrient but is also highly toxic. In yeast and plant cells, a key detoxifying mechanism involves iron sequestration into intracellular storage compartments, mediated by members of the vacuolar iron-transporter (VIT) family of proteins. Here we study the VIT homologue from the malaria parasites Plasmodium falciparum (PfVIT) and Plasmodium berghei (PbVIT). PfVIT-mediated iron transport in a yeast heterologous expression system is saturable (Km ∼ 14.7 μM), and selective for Fe(2+) over other divalent cations. PbVIT-deficient P. berghei lines (Pbvit(-)) show a reduction in parasite load in both liver and blood stages of infection in mice. Moreover, Pbvit(-) parasites have higher levels of labile iron in blood stages and are more sensitive to increased iron levels in liver stages, when compared with wild-type parasites. Our data are consistent with Plasmodium VITs playing a major role in iron detoxification and, thus, normal development of malaria parasites in their mammalian host.

High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands.

PubMed

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

2015-05-01

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. 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). 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. 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 outbreaks due to travel to nearby islands

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

Destruction of newly released red blood cells in space flight

NASA Technical Reports Server (NTRS)

Alfrey, C. P.; Udden, M. M.; Huntoon, C. L.; Driscoll, T.

1996-01-01

Space flight results in a rapid change in total blood volume, plasma volume, and red blood cell mass because the space to contain blood is decreased. The plasma volume and total blood volume decreases during the first hours in space and remain at a decreased level for the remainder of the flight. During the first several hours following return to earth, plasma volume and total blood volume increase to preflight levels. During the first few days in space recently produced red blood cells disappear from the blood resulting in a decrease in red blood cell mass of 10-15%. Red cells 12 d old or older survive normally and production of new cells continues at near preflight levels. After the first few days in space, the red cell mass is stable at the decreased level. Following return to earth the hemoglobin and red blood cell mass concentrations decrease reflecting the increase in plasma volume. The erythropoietin levels increase responding to "postflight anemia"; red cell production increases, and the red cell mass is restored to preflight levels after several weeks.

Parvovirus B19 infection transmitted by transfusion of red blood cells confirmed by molecular analysis of linked donor and recipient samples.

PubMed

Yu, Mei-Ying W; Alter, Harvey J; Virata-Theimer, Maria Luisa A; Geng, Yansheng; Ma, Li; Schechterly, Cathy A; Colvin, Camilla A; Luban, Naomi L C

2010-08-01

Extremely high viremic levels of parvovirus B19 (B19V) can be found in acutely infected, but asymptomatic donors. However, reports of transmission by single-donor blood components are rare. In this prospective study, paired donor-recipient samples were used to investigate the transfusion risk. Posttransfusion plasma or blood samples from recipients were tested for B19V DNA by polymerase chain reaction, generally at 4 and 8 weeks, and for anti-B19V immunoglobulin (Ig)G by enzyme immunoassay, at 12 and 24 weeks. To rule out infection unrelated to transfusion, pretransfusion samples and linked donor's samples for each B19V DNA-positive recipient were assayed for B19V DNA and anti-B19V IgG and IgM. To confirm transmission, sequencing and phylogenetic analysis were performed. A total of 14 of 869 (1.6%) recipients were B19V DNA positive, but only 1 of 869 (0.12%; 95% confidence interval, 0.0029%-0.6409%) was negative for B19V DNA and anti-B19V IgG before transfusion and seroconverted posttransfusion. This newly infected patient received 5 × 10(10) IU B19V DNA in one red blood cell (RBC) unit from an acutely infected anti-B19V-negative donor in addition to RBCs from three other donors that cumulatively contained 1320 IU of anti-B19V IgG. DNA sequencing and phylogenetic analysis showed that sequences from the linked donor and recipient were identical (Genotype 1), thus establishing transfusion transmission. The 0.12% transmission rate documented here, although low, could nonetheless result in hundreds or thousands of infections annually in the United States based on calculated confidence limits. Although most would be asymptomatic, some could have severe clinical outcomes, especially in neonates and those with immunocompromised or hemolytic states. © 2010 American Association of Blood Banks.

Immunization with apical membrane antigen 1 confers sterile infection-blocking immunity against Plasmodium sporozoite challenge in a rodent model.

PubMed

Schussek, Sophie; Trieu, Angela; Apte, Simon H; Sidney, John; Sette, Alessandro; Doolan, Denise L

2013-10-01

Apical membrane antigen 1 (AMA-1) is a leading blood-stage malaria vaccine candidate. Consistent with a key role in erythrocytic invasion, AMA-1-specific antibodies have been implicated in AMA-1-induced protective immunity. AMA-1 is also expressed in sporozoites and in mature liver schizonts where it may be a target of protective cell-mediated immunity. Here, we demonstrate for the first time that immunization with AMA-1 can induce sterile infection-blocking immunity against Plasmodium sporozoite challenge in 80% of immunized mice. Significantly higher levels of gamma interferon (IFN-γ)/interleukin-2 (IL-2)/tumor necrosis factor (TNF) multifunctional T cells were noted in immunized mice than in control mice. We also report the first identification of minimal CD8(+) and CD4(+) T cell epitopes on Plasmodium yoelii AMA-1. These data establish AMA-1 as a target of both preerythrocytic- and erythrocytic-stage protective immune responses and validate vaccine approaches designed to induce both cellular and humoral immunity.

Morphologic and molecular study of hemoparasites in wild corvids and evidence of sequence identity with Plasmodium DNA detected in captive black-footed penguins (Spheniscus demersus).

PubMed

Leclerc, Antoine; Chavatte, Jean-Marc; Landau, Irène; Snounou, Georges; Petit, Thierry

2014-09-01

A morphologic and molecular epidemiologic investigation was conducted on a captive African black-footed penguin (Spheniscus demersus) colony with a history of Plasmodium infections at La Palmyre Zoo (France). Each penguin received 12.5 mg of pyrimethamine twice a week as a prophylaxis every year from April to November. Although Plasmodium parasites were not detected in blood smears and tissues collected from the penguins, various blood parasites were recorded in blood smears from wild Eurasian magpies (Pica pica) and carrion crows (Corvus corone) sampled at the same time in the study area. These parasites consisted of several Plasmodium spp. (P. lenoblei, P. dorsti, P bioccai, P. relictum, P. dherteae, P. beaucournui, P. maior, P. tranieri, and P. snounoui), Parahaemoproteus spp., Trypanosoma spp., and Leucocytozoon spp. On the other hand, nested polymerase chain reaction enabled detection of Plasmodium DNA in 28/44 (64%) penguins, 15/25 (60%) magpies, and 4/9 (44%) crows. Sequencing and phylogenetic analyses indicated that the parasite DNA amplified from the penguins, magpies, and crows were similar. Magpies and crows could therefore act as a reservoir for penguin Plasmodium infections, which may be more prevalent than previously thought. Morphologic characterization of the Plasmodium spp. detected in the penguins, as well as further biological and epidemiologic studies, are needed to fully understand the transmission of Plasmodium parasites to captive penguins.

Changing epidemiology of malaria in Sabah, Malaysia: increasing incidence of Plasmodium knowlesi.

PubMed

William, Timothy; Jelip, Jenarun; Menon, Jayaram; Anderios, Fread; Mohammad, Rashidah; Awang Mohammad, Tajul A; Grigg, Matthew J; Yeo, Tsin W; Anstey, Nicholas M; Barber, Bridget E

2014-10-02

While Malaysia has had great success in controlling Plasmodium falciparum and Plasmodium vivax, notifications of Plasmodium malariae and the microscopically near-identical Plasmodium knowlesi increased substantially over the past decade. However, whether this represents microscopic misdiagnosis or increased recognition of P. knowlesi has remained uncertain. To describe the changing epidemiology of malaria in Sabah, in particular the increasing incidence of P. knowlesi, a retrospective descriptive study was undertaken involving a review of Department of Health malaria notification data from 2012-2013, extending a previous review of these data from 1992-2011. In addition, malaria PCR and microscopy data from the State Public Health Laboratory were reviewed to estimate the accuracy of the microscopy-based notification data. Notifications of P. malariae/P. knowlesi increased from 703 in 2011 to 815 in 2012 and 996 in 2013. Notifications of P. vivax and P. falciparum decreased from 605 and 628, respectively, in 2011, to 297 and 263 in 2013. In 2013, P. malariae/P. knowlesi accounted for 62% of all malaria notifications compared to 35% in 2011. Among 1,082 P. malariae/P. knowlesi blood slides referred for PCR testing during 2011-2013, there were 924 (85%) P. knowlesi mono-infections, 30 (2.8%) P. falciparum, 43 (4.0%) P. vivax, seven (0.6%) P. malariae, six (0.6%) mixed infections, 31 (2.9%) positive only for Plasmodium genus, and 41 (3.8%) Plasmodium-negative. Plasmodium knowlesi mono-infection accounted for 32/156 (21%) and 33/87 (38%) blood slides diagnosed by microscopy as P. falciparum and P. vivax, respectively. Twenty-six malaria deaths were reported during 2010-2013, including 12 with 'P. malariae/P. knowlesi' (all adults), 12 with P. falciparum (seven adults), and two adults with P. vivax. Notifications of P. malariae/P. knowlesi in Sabah are increasing, with this trend likely reflecting a true increase in incidence of P. knowlesi and presenting a major threat

Imported Malaria in Turkey: The Importance of Diagnosis and Treatment of Plasmodium falciparum/Plasmodium vivax Mixed Infection.

PubMed

Tünger, Özlem; Çakmak, Akide; Özbilgin, Ahmet; Tunalı, Varol; Çetin, Çiğdem Banu

2018-05-21

The most common types of malaria in the world are Plasmodium vivax and P. falciparum. In countries where both species are endemic, P. vivax and P. falciparum coinfection also occurs. Thus, the possibility of mixed malaria in Turkey should always be considered in cases with a traveling history to these countries. Here, we report a case of P. vivax/P. falciparum mixed infection that was diagnosed as P. falciparum malaria in Ethiopia. However, the administered treatment was inadequate, and infection recurred because of the miss in the diagnosis of P. vivax malaria, for which an effective drug for hypnozoites was not administered. This case report emphasizes the importance of diagnosis, correct and adequate treatment of infections, and a close follow-up of diseases.

Effects of helicopter transport on red blood cell components.

PubMed

Otani, Taiichi; Oki, Ken-ichi; Akino, Mitsuaki; Tamura, Satoru; Naito, Yuki; Homma, Chihiro; Ikeda, Hisami; Sumita, Shinzou

2012-01-01

There are no reported studies on whether a helicopter flight affects the quality and shelf-life of red blood cells stored in mannitol-adenine-phosphate. Seven days after donation, five aliquots of red blood cells from five donors were packed into an SS-BOX-110 container which can maintain the temperature inside the container between 2 °C and 6 °C with two frozen coolants. The temperature of an included dummy blood bag was monitored. After the box had been transported in a helicopter for 4 hours, the red blood cells were stored again and their quality evaluated at day 7 (just after the flight), 14, 21 and 42 after donation. Red blood cell quality was evaluated by measuring adenosine triphosphate, 2,3-diphosphoglycerate, and supernatant potassium, as well as haematocrit, intracellular pH, glucose, supernatant haemoglobin, and haemolysis rate at the various time points. During the experiment the recorded temperature remained between 2 and 6 °C. All data from the red blood cells that had undergone helicopter transportation were the same as those from a control group of red blood cell samples 7 (just after the flight), 14, 21, and 42 days after the donation. Only supernatant Hb and haemolysis rate 42 days after the donation were slightly increased in the helicopter-transported group of red blood cell samples. All other parameters at 42 days after donation were the same in the two groups of red blood cells. These results suggest that red blood cells stored in mannitol-adenine-phosphate are not significantly affected by helicopter transportation. The differences in haemolysis by the end of storage were small and probably not of clinical significance.

Cytosolic Extract Induces Tir Translocation and Pedestals in EPEC-Infected Red Blood Cells

PubMed Central

Swimm, Alyson I; Kalman, Daniel

2008-01-01

Enteropathogenic Escherichia coli (EPEC) are deadly contaminants in water and food, and induce protrusion of actin-filled membranous pedestals beneath themselves upon attachment to intestinal epithelia. Pedestal formation requires clustering of Tir and subsequent recruitment of cellular tyrosine kinases including Abl, Arg, and Etk as well as signaling molecules Nck, N-WASP, and Arp2/3 complex. We have developed a cytosolic extract-based cellular system that recapitulates actin pedestal formation in permeabilized red blood cells (RBC) infected with EPEC. RBC support attachment of EPEC and translocation of virulence factors, but not pedestal formation. We show here that extract induces a rapid Ca++-dependent release of Tir from the EPEC Type III secretion system, and that cytoplasmic factor(s) present in the extract facilitate translocation of Tir into the RBC plasma membrane. We show that Abl and related kinases in the extract phosphorylate Tir and that actin polymerization can be reconstituted in infected RBC following addition of cytosolic extract. Reconstitution requires the bacterial virulence factors Tir and intimin, and phosphorylation of Tir on tyrosine residue 474 results in the recruitment of Nck, N-WASP, and Arp2/3 complex beneath attached bacteria at sites of actin polymerization. Together these data describe a biochemical system for dissection of host components that mediate Type III secretion and the mechanisms by which complexes of proteins are recruited to discrete sites within the plasma membrane to initiate localized actin polymerization and morphological changes. PMID:18208322

Plasmodium falciparum: a simplified technique for obtaining singly infected erythrocytes.

PubMed

Puthia, Manoj K; Tan, Kevin S W

2005-02-01

We report the development of a simple technique involving 15 ml polypropylene tubes and a rotatory incubator for obtaining erythrocytes singly infected with Plasmodium falciparum. This technique will be useful for cloning of the parasite. Our finding that P. falciparum merozoite invasion is inhibited during rotation suggests that this method may also be useful for the study of parasite-erythrocyte interactions under dynamic circulatory conditions.

Use of Blood Smears and Dried Blood Spots for Polymerase Chain Reaction–Based Detection and Quantification of Bacterial Infection and Plasmodium falciparum in Severely Ill Febrile African Children

PubMed Central

Wihokhoen, Benchawan; Dondorp, Arjen M.; Turner, Paul; Woodrow, Charles J.; Imwong, Mallika

2016-01-01

Molecular approaches offer a means of testing archived samples stored as dried blood spots in settings where standard blood cultures are not possible. Peripheral blood films are one suggested source of material, although the sensitivity of this approach has not been well defined. Thin blood smears and dried blood spots from a severe pediatric malaria study were assessed using specific polymerase chain reaction (PCR) primers to detect non-typhoidal Salmonella (NTS; MisL gene), Streptococcus pneumoniae (lytA), and Plasmodium falciparum (18S rRNA). Of 16 cases of NTS and S. pneumoniae confirmed on blood culture, none were positive by PCR using DNA extracts from blood films or dried blood spots. In contrast, four of 36 dried blood spots and two of 178 plasma samples were PCR positive for S. pneumoniae, despite negative bacterial blood cultures, suggesting false positives. Quantitative assessment revealed that the effective concentration of P. falciparum DNA in blood films was three log orders of magnitude lower than for dried blood spots. The P. falciparum kelch13 gene could not be amplified from blood films. These findings question the value of blood PCR-based approaches for detection of NTS and S. pneumoniae, and show that stored blood films are an inefficient method of studying P. falciparum. PMID:26711525

Three species of Plasmodium from Canada geese, Branta canadensis

USGS Publications Warehouse

Herman, C.M.; Barrow, J.H.

1967-01-01

Studies on Canada geese at the Seney National Wildlife Refuge in northern Michigan during the past few years have uncovered at least three species of Plasmodium: P circumflexum, P. relictum, and P. vaughani. Although rarely observed in direct blood smears from the wild hosts, isodiagnosis, using primarily domestic geese as recipients, revealed a prevalence of 60 percent in random samplings of the population. P. circumflexum is the most prevalent and mixed infections have been noted. In experimental infections, induced by blood inoculation, the malaria produced by P. circumflexum produces about a 70 percent mortality in Canada geese and about a 10 percent mortality in domestic geese.

A zoonotic human infection with simian malaria, Plasmodium knowlesi, in Central Kalimantan, Indonesia.

PubMed

Setiadi, Wuryantari; Sudoyo, Herawati; Trimarsanto, Hidayat; Sihite, Boy Adventus; Saragih, Riahdo Juliarman; Juliawaty, Rita; Wangsamuda, Suradi; Asih, Puji Budi Setia; Syafruddin, Din

2016-04-16

The Indonesian archipelago is endemic for malaria. Although Plasmodium falciparum and P. vivax are the most common causes for malaria cases, P. malariae and P. ovale are also present in certain regions. Zoonotic case of malaria had just became the attention of public health communities after the Serawak study in 2004. However, zoonotic case in Indonesia is still under reported; only one published report of knowlesi malaria in South Kalimantan in 2010. A case of Plasmodium knowlesi infection in a worker from a charcoal mining company in Central Kalimantan, Indonesia was described. The worker suffered from fever following his visit to a lowland forest being cut and converted into a new mining location. This study confirmed a zoonotic infection using polymerase chain reaction amplification and Sanger sequencing of plasmodial DNA encoding the mitochondrial cytochrome c oxidase subunit I (mtCOI).

Evaluation of blood and muscle tissues for molecular detection and characterization of hematozoa infections in northern pintails (Anas acuta) wintering in California

USGS Publications Warehouse

Ramey, Andy M.; Schmutz, Joel A.; Fleskes, Joseph P.; Yabsley, Michael J.

2013-01-01

Information on the molecular detection of hematozoa from different tissue types and multiple years would be useful to inform sample collection efforts and interpret results of meta-analyses or investigations spanning multiple seasons. In this study, we tested blood and muscle tissue collected from northern pintails (Anas acuta) during autumn and winter of different years to evaluate prevalence and genetic diversity ofLeucocytozoon, Haemoproteus, and Plasmodium infections in this abundant waterfowl species of the Central Valley of California. We first compared results for paired blood and wing muscle samples to assess the utility of different tissue types for molecular investigations of haemosporidian parasites. Second, we explored inter-annual variability of hematozoa infection in Central Valley northern pintails and investigated possible effects of age, sex, and sub-region of sample collection on estimated parasite detection probability and prevalence. We found limited evidence for differences between tissue types in detection probability and prevalence ofLeucocytozoon, Haemoproteus, and Plasmodium parasites, which supports the utility of both sample types for obtaining information on hematozoan infections. However, we detected 11 haemosporidian mtDNA cyt bhaplotypes in blood samples vs. six in wing muscle tissue collected during the same sample year suggesting an advantage to using blood samples for investigations of genetic diversity. Estimated prevalence ofLeucocytozoon parasites was greater during 2006–2007 as compared to 2011–2012 and four unique haemosporidian mtDNA cyt b haplotypes were detected in the former sample year but not in the latter. Seven of 15 mtDNA cyt b haplotypes detected in northern pintails had 100% identity with previously reported hematozoa lineages detected in waterfowl (Haemoproteus and Leucocytozoon) or other avian taxa (Plasmodium) providing support for lack of host specificity for some parasite lineages.

Test characteristics of the SD FK80 Plasmodium falciparum/Plasmodium vivax malaria rapid diagnostic test in a non-endemic setting

PubMed Central

2009-01-01

Background The SD FK80 P.f/P.v Malaria Antigen Rapid Test (Standard Diagnostics, Korea) (FK80) is a three-band malaria rapid diagnostic test detecting Plasmodium falciparum histidine-rich protein-2 (HRP-2) and Plasmodium vivax-specific lactate dehydrogenase (Pv-pLDH). The present study assessed its performance in a non-endemic setting. Methods Stored blood samples (n = 416) from international travellers suspected of malaria were used, with microscopy corrected by PCR as the reference method. Samples infected by Plasmodium falciparum (n = 178), Plasmodium vivax (n = 99), Plasmodium ovale (n = 75) and Plasmodium malariae (n = 24) were included, as well as 40 malaria negative samples. Results Overall sensitivities for the diagnosis of P. falciparum and P. vivax were 91.6% (95% confidence interval (CI): 86.2% - 95.0%) and 75.8% (65.9% - 83.6%). For P. falciparum, sensitivity at parasite densities ≥ 100/μl was 94.6% (88.8% - 97.6%); for P. vivax, sensitivity at parasite densities ≥ 500/μl was 86.8% (75.4% - 93.4%). Four P. falciparum samples showed a Pv-pLDH line, three of them had parasite densities exceeding 50.000/μl. Two P. vivax samples, one P. ovale and one P. malariae sample showed a HRP-2 line. For the HRP-2 and Pv-pLDH lines, respectively 81.4% (136/167) and 55.8% (43/77) of the true positive results were read as medium or strong line intensities. The FK80 showed good reproducibility and reliability for test results and line intensities (kappa values for both exceeding 0.80). Conclusion The FK80 test performed satisfactorily in diagnosing P. falciparum and P. vivax infections in a non-endemic setting. PMID:19930609

Effects of helicopter transport on red blood cell components

PubMed Central

Otani, Taiichi; Oki, Ken-ichi; Akino, Mitsuaki; Tamura, Satoru; Naito, Yuki; Homma, Chihiro; Ikeda, Hisami; Sumita, Shinzou

2012-01-01

Background There are no reported studies on whether a helicopter flight affects the quality and shelf-life of red blood cells stored in mannitol-adenine-phosphate. Materials and methods Seven days after donation, five aliquots of red blood cells from five donors were packed into an SS-BOX-110 container which can maintain the temperature inside the container between 2 °C and 6 °C with two frozen coolants. The temperature of an included dummy blood bag was monitored. After the box had been transported in a helicopter for 4 hours, the red blood cells were stored again and their quality evaluated at day 7 (just after the flight), 14, 21 and 42 after donation. Red blood cell quality was evaluated by measuring adenosine triphosphate, 2,3-diphosphoglycerate, and supernatant potassium, as well as haematocrit, intracellular pH, glucose, supernatant haemoglobin, and haemolysis rate at the various time points. Results During the experiment the recorded temperature remained between 2 and 6 °C. All data from the red blood cells that had undergone helicopter transportation were the same as those from a control group of red blood cell samples 7 (just after the flight), 14, 21, and 42 days after the donation. Only supernatant Hb and haemolysis rate 42 days after the donation were slightly increased in the helicopter-transported group of red blood cell samples. All other parameters at 42 days after donation were the same in the two groups of red blood cells. Discussion These results suggest that red blood cells stored in mannitol-adenine-phosphate are not significantly affected by helicopter transportation. The differences in haemolysis by the end of storage were small and probably not of clinical significance. PMID:22153688

Associations Between Helminth Infections, Plasmodium falciparum Parasite Carriage and Antibody Responses to Sexual and Asexual Stage Malarial Antigens.

PubMed

Ateba-Ngoa, Ulysse; Jones, Sophie; Zinsou, Jeannot Fréjus; Honkpehedji, Josiane; Adegnika, Ayola Akim; Agobe, Jean-Claude Dejon; Massinga-Loembe, Marguerite; Mordmüller, Benjamin; Bousema, Teun; Yazdanbakhsh, Maria

2016-08-03

Infections with helminths and Plasmodium spp. overlap in their geographical distribution. It has been postulated that helminth infections may influence malarial transmission by altering Plasmodium falciparum gametocytogenesis. This cross-sectional study assessed the effect of helminth infections on P. falciparum gametocyte carriage and on humoral immune responses to sexual stage antigens in Gabon. Schistosoma haematobium and filarial infections as well as P. falciparum asexual forms and gametocyte carriage were determined. The antibody responses measured were to sexual (Pfs230, Pfs48/45) and asexual P. falciparum antigens (AMA1, MSP1, and GLURP). A total of 287 subjects were included. The prevalence of microscopically detectable P. falciparum asexual parasites was higher in S. haematobium-infected subjects in comparison to their uninfected counterparts (47% versus 26%, P = 0.003), but this was not different when filarial infections were considered. Plasmodium falciparum gametocyte carriage was similar between Schistosoma- or filaria-infected and uninfected subjects. We observed a significant decrease of Pfs48/45 immunoglobulin G titer in S. haematobium-infected subjects (P = 0.037), whereas no difference was seen for Pfs230 antibody titer, nor for antibodies to AMA1, MSP1, or GLURP. Our findings suggest an effect of S. haematobium on antibody responses to some P. falciparum gametocyte antigens that may have consequences for transmission-blocking immunity. © The American Society of Tropical Medicine and Hygiene.

Occurrence of Plasmodium in Anatidae

USGS Publications Warehouse

Herman, C.M.; Kocan, R.M.

1970-01-01

Until a little over a decade ago reports of Plasrnodium in geese, ducks, and swans were the result of examination of single blood smears from wild birds. One would gather from the earlier studies that Anatidae are infrequently infected. During the past decade we have conducted studies on prevalence of Plasmodium by an isodiagnosis technique, inoculating blood from wild birds into captive young geese, ducks, and other species of birds and determining the status of infection in the donors by examination of repetitive blood smears from the recipients. Examination by this technique of a series of adult Canada geese from the Seney National Wildlife Refuge in northern Michigan uncovered a prevalence of 60% during five successive years. Domestic geese were the primary recipients but we found that several other species of geese, ducks, and gulls were also susceptible. Similar studies on Canada geese from other areas (Maryland, New Jersey, New York, and southern Michigan) uncovered infection rates from zero to 27%. Following isolation of Plasmodlum in a single canvasback duck (Aythya valisineria) in southern Michigan by inoculation into a domestic duck, a series of 88 canvasbacks from Chesapeake Bay in Maryland this winter uncovered an infection rate of 27%. The most common parasite observed in both the geese and was as P. circumflexum.

Machine learning-based in-line holographic sensing of unstained malaria-infected red blood cells.

PubMed

Go, Taesik; Kim, Jun H; Byeon, Hyeokjun; Lee, Sang J

2018-04-19

Accurate and immediate diagnosis of malaria is important for medication of the infectious disease. Conventional methods for diagnosing malaria are time consuming and rely on the skill of experts. Therefore, an automatic and simple diagnostic modality is essential for healthcare in developing countries that lack the expertise of trained microscopists. In the present study, a new automatic sensing method using digital in-line holographic microscopy (DIHM) combined with machine learning algorithms was proposed to sensitively detect unstained malaria-infected red blood cells (iRBCs). To identify the RBC characteristics, 13 descriptors were extracted from segmented holograms of individual RBCs. Among the 13 descriptors, 10 features were highly statistically different between healthy RBCs (hRBCs) and iRBCs. Six machine learning algorithms were applied to effectively combine the dominant features and to greatly improve the diagnostic capacity of the present method. Among the classification models trained by the 6 tested algorithms, the model trained by the support vector machine (SVM) showed the best accuracy in separating hRBCs and iRBCs for training (n = 280, 96.78%) and testing sets (n = 120, 97.50%). This DIHM-based artificial intelligence methodology is simple and does not require blood staining. Thus, it will be beneficial and valuable in the diagnosis of malaria. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The pathogenesis of Plasmodium falciparum malaria in humans: insights from splenic physiology

PubMed Central

Safeukui, Innocent; Deplaine, Guillaume; Brousse, Valentine; Prendki, Virginie; Thellier, Marc; Turner, Gareth D.; Mercereau-Puijalon, Odile

2011-01-01

Clinical manifestations of Plasmodium falciparum infection are induced by the asexual stages of the parasite that develop inside red blood cells (RBCs). Because splenic microcirculatory beds filter out altered RBCs, the spleen can innately clear subpopulations of infected or uninfected RBC modified during falciparum malaria. The spleen appears more protective against severe manifestations of malaria in naïve than in immune subjects. The spleen-specific pitting function accounts for a large fraction of parasite clearance in artemisinin-treated patients. RBC loss contributes to malarial anemia, a clinical form associated with subacute progression, frequent splenomegaly, and relatively low parasitemia. Stringent splenic clearance of ring-infected RBCs and uninfected, but parasite-altered, RBCs, may altogether exacerbate anemia and reduce the risks of severe complications associated with high parasite loads, such as cerebral malaria. The age of the patient directly influences the risk of severe manifestations. We hypothesize that coevolution resulting in increased splenic clearance of P. falciparum–altered RBCs in children favors the survival of the host and, ultimately, sustained parasite transmission. This analysis of the RBC–spleen dynamic interactions during P falciparum infection reflects both data and hypotheses, and provides a framework on which a more complete immunologic understanding of malaria pathogenesis may be elaborated. PMID:20852127

Equivalent susceptibility of Anopheles gambiae M and S molecular forms and Anopheles arabiensis to Plasmodium falciparum infection in Burkina Faso

PubMed Central

2013-01-01

Background The Anopheles gambiae sensu lato (s.l.) species complex in Burkina Faso consists of Anopheles arabiensis, and molecular forms M and S of Anopheles gambiae sensu stricto (s.s.). Previous studies comparing the M and S forms for level of infection with Plasmodium falciparum have yielded conflicting results. Methods Mosquito larvae were sampled from natural pools, reared to adulthood under controlled conditions, and challenged with natural P. falciparum by experimental feeding with blood from gametocyte carriers. Oocyst infection prevalence and intensity was determined one week after infection. DNA from carcasses was genotyped to identify species and molecular form. Results In total, 7,400 adult mosquitoes grown from wild-caught larvae were challenged with gametocytes in 29 experimental infections spanning four transmission seasons. The overall infection prevalence averaged 40.7% for A. gambiae M form, 41.4% for A. gambiae S form, and 40.1% for A. arabiensis. There was no significant difference in infection prevalence or intensity between the three population groups. Notably, infection experiments in which the population groups were challenged in parallel on the same infective blood displayed less infection difference between population groups, while infections with less balanced composition of population groups had lower statistical power and displayed apparent differences that fluctuated more often from the null average. Conclusion The study clearly establishes that, at the study site in Burkina Faso, there is no difference in genetic susceptibility to P. falciparum infection between three sympatric population groups of the A. gambiae s.l. complex. Feeding the mosquito groups on the same infective blood meal greatly increases statistical power. Conversely, comparison of the different mosquito groups between, rather than within, infections yields larger apparent difference between mosquito groups, resulting from lower statistical power and greater noise

Consistent Safety and Infectivity in Sporozoite Challenge Model of Plasmodium vivax in Malaria-Naive Human Volunteers

PubMed Central

Herrera, Sócrates; Solarte, Yezid; Jordán-Villegas, Alejandro; Echavarría, Juan Fernando; Rocha, Leonardo; Palacios, Ricardo; Ramírez, Óscar; Vélez, Juan D.; Epstein, Judith E.; Richie, Thomas L.; Arévalo-Herrera, Myriam

2011-01-01

A safe and reproducible Plasmodium vivax infectious challenge method is required to evaluate the efficacy of malaria vaccine candidates. Seventeen healthy Duffy (+) and five Duffy (−) subjects were randomly allocated into three (A–C) groups and were exposed to the bites of 2–4 Anopheles albimanus mosquitoes infected with Plasmodium vivax derived from three donors. Duffy (−) subjects were included as controls for each group. Clinical manifestations of malaria and parasitemia were monitored beginning 7 days post-challenge. All Duffy (+) volunteers developed patent malaria infection within 16 days after challenge. Prepatent period determined by thick smear, was longer for Group A (median 14.5 d) than for Groups B and C (median 10 d/each). Infected volunteers recovered rapidly after treatment with no serious adverse events. The bite of as low as two P. vivax-infected mosquitoes provides safe and reliable infections in malaria-naive volunteers, suitable for assessing antimalarial and vaccine efficacy trials. PMID:21292872

Red blood cell transfusion in newborn infants

PubMed Central

Whyte, Robin K; Jefferies, Ann L

2014-01-01

Red blood cell transfusion is an important and frequent component of neonatal intensive care. The present position statement addresses the methods and indications for red blood cell transfusion of the newborn, based on a review of the current literature. The most frequent indications for blood transfusion in the newborn are the acute treatment of perinatal hemorrhagic shock and the recurrent correction of anemia of prematurity. Perinatal hemorrhagic shock requires immediate treatment with large quantities of red blood cells; the effects of massive transfusion on other blood components must be considered. Some guidelines are now available from clinical trials investigating transfusion in anemia of prematurity; however, considerable uncertainty remains. There is weak evidence that cognitive impairment may be more severe at follow-up in extremely low birth weight infants transfused at lower hemoglobin thresholds; therefore, these thresholds should be maintained by transfusion therapy. Although the risks of transfusion have declined considerably in recent years, they can be minimized further by carefully restricting neonatal blood sampling. PMID:24855419

Antiplasmodial activity of two medicinal plants against clinical isolates of Plasmodium falciparum and Plasmodium berghei infected mice.

PubMed

Attemene, Serge David Dago; Beourou, Sylvain; Tuo, Karim; Gnondjui, Albert Alloh; Konate, Abibatou; Toure, Andre Offianan; Kati-Coulibaly, Seraphin; Djaman, Joseph Alico

2018-03-01

Malaria is an infectious and deadly parasitic disease, associated with fever, anaemia and other ailments. Unfortunately the upsurge of plasmodium multidrug resistant constrained researchers to look for new effective drugs. Medicinal plants seem to be an unquenchable source of bioactive principles in the treatment of various diseases. The aim of this study was to assess the antiplasmodial activity of two Ivorian medicinal plants. The in vitro activity was evaluated against clinical isolates and Plasmodium falciparum K1 multidrug resistant strain using the fluorescence based SYBR green I assay. The in vivo bioassay was carried out using the classical 4 day suppressive and curative tests on Plasmodium berghei infected mice. Results showed that the in vitro bioassay of both plant extracts were found to exhibit a promising and moderate antiparasitic effects on clinical isolates (5 µg/mL < IC 50  < 15 µg/mL) and Plasmodium falciparum multidrug resistant K1 strain (15 µg/mL < IC 50  < 50 µg/mL). Furthermore, the in vivo antiplasmodial screening of both extracts showed a significant decrease in parasitemia, which was dose-dependent. Body temperature in mice treated with both extracts at experimental doses increased, compared to the negative control group and was dose-dependent. As for mice body weight a significant decrease ( p  < 0.001) was noticed in the negative control group compared to tested groups of animals. The hydroethanolic stem bark extract of Anthocleista djalonensis A Chev and leaves extract of Ziziphus mauritiana Lam exhibited anti-malarial activities. Therefore, the bioactive compounds of both plant extracts need to be investigated.

Plasmodium falciparum, but not P. vivax, can induce erythrocytic apoptosis.

PubMed

Totino, Paulo Renato Rivas; Magalhães, Aline das Dores; Alves, Eliana Brasil; Costa, Monica Regina Farias; de Lacerda, Marcus Vinícius Guimarães; Daniel-Ribeiro, Cláudio Tadeu; Ferreira-da-Cruz, Maria de Fátima

2014-10-18

Apoptosis can occur in red blood cells (RBC) and seems to be involved in hematologic disorders related to many diseases. In malaria it is known that parasitized RBC (pRBC) is involved in the development of anemia and thrombosis; however, non-parasitized RBC (nRBC) apoptosis could amplify these malaria-associated hematologic events. In fact, in experimental malaria, increased levels of apoptosis were observed in nRBC during lethal Plasmodium yoelii 17XL infection, but in human malaria erythrocytic apoptosis has never been studied. The present study was performed to investigate if nRBC apoptosis also occurs in P. vivax and P. falciparum infections. Apoptosis of nRBC was evaluated in blood samples of P. vivax malaria patients and clinically healthly individuals living in Manaus, Brazil, both ex vivo and after incubation of RBC for 24 h. Additionally, the capacity of plasma from P. vivax or P. falciparum patients was tested for induction of in vitro apoptosis of normal RBC from a clinically healthy individual living in a non-endemic malaria region. Apoptosis was detected by flow cytometry using annexin V staining. In contrast to experimental malaria that significantly increased the levels of apoptotic nRBC both ex-vivo and after 24 h of incubation, no significant alteration on apoptotic nRBC rates was detected in P. vivax infected patients when compared with non-infected control individuals. Similar results were observed when plasma of these P. vivax patients was incubated with normal RBC. Conversely, plasma from P. falciparum-infected subjects induced significant apoptosis of these cells. Apoptosis of normal RBC can be induced by plasma from individuals with P. falciparum (but not with P. vivax) malaria. This finding could reflect the existence of erythrocytic apoptosis during infection that could contribute to the pathogenesis of hematological and vascular complications associated with falciparum malaria.

21 CFR 864.7100 - Red blood cell enzyme assay.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Red blood cell enzyme assay. 864.7100 Section 864...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7100 Red blood cell enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure the activity in...

Larval nutrition differentially affects adult fitness and Plasmodium development in the malaria vectors Anopheles gambiae and Anopheles stephensi

PubMed Central

2013-01-01

Background Mosquito fitness is determined largely by body size and nutritional reserves. Plasmodium infections in the mosquito and resultant transmission of malaria parasites might be compromised by the vector’s nutritional status. We studied the effects of nutritional stress and malaria parasite infections on transmission fitness of Anopheles mosquitoes. Methods Larvae of Anopheles gambiae sensu stricto and An. stephensi were reared at constant density but with nutritionally low and high diets. Fitness of adult mosquitoes resulting from each dietary class was assessed by measuring body size and lipid, protein and glycogen content. The size of the first blood meal was estimated by protein analysis. Mosquitoes of each dietary class were fed upon a Plasmodium yoelii nigeriensis-infected mouse, and parasite infections were determined 5 d after the infectious blood meal by dissection of the midguts and by counting oocysts. The impact of Plasmodium infections on gonotrophic development was established by dissection. Results Mosquitoes raised under low and high diets emerged as adults of different size classes comparable between An. gambiae and An. stephensi. In both species low-diet females contained less protein, lipid and glycogen upon emergence than high-diet mosquitoes. The quantity of larval diet impacted strongly upon adult blood feeding and reproductive success. The prevalence and intensity of P. yoelii nigeriensis infections were reduced in low-diet mosquitoes of both species, but P. yoelii nigeriensis impacted negatively only on low-diet, small-sized An. gambiae considering survival and egg maturation. There was no measurable fitness effect of P. yoelii nigeriensis on An. stephensi. Conclusions Under the experimental conditions, small-sized An. gambiae expressed high mortality, possibly caused by Plasmodium infections, the species showing distinct physiological concessions when nutrionally challenged in contrast to well-fed, larger siblings. Conversely, An

NSR-seq transcriptional profiling enables identification of a gene signature of Plasmodium falciparum parasites infecting children.

PubMed

Vignali, Marissa; Armour, Christopher D; Chen, Jingyang; Morrison, Robert; Castle, John C; Biery, Matthew C; Bouzek, Heather; Moon, Wonjong; Babak, Tomas; Fried, Michal; Raymond, Christopher K; Duffy, Patrick E

2011-03-01

Malaria caused by Plasmodium falciparum results in approximately 1 million annual deaths worldwide, with young children and pregnant mothers at highest risk. Disease severity might be related to parasite virulence factors, but expression profiling studies of parasites to test this hypothesis have been hindered by extensive sequence variation in putative virulence genes and a preponderance of host RNA in clinical samples. We report here the application of RNA sequencing to clinical isolates of P. falciparum, using not-so-random (NSR) primers to successfully exclude human ribosomal RNA and globin transcripts and enrich for parasite transcripts. Using NSR-seq, we confirmed earlier microarray studies showing upregulation of a distinct subset of genes in parasites infecting pregnant women, including that encoding the well-established pregnancy malaria vaccine candidate var2csa. We also describe a subset of parasite transcripts that distinguished parasites infecting children from those infecting pregnant women and confirmed this observation using quantitative real-time PCR and mass spectrometry proteomic analyses. Based on their putative functional properties, we propose that these proteins could have a role in childhood malaria pathogenesis. Our study provides proof of principle that NSR-seq represents an approach that can be used to study clinical isolates of parasites causing severe malaria syndromes as well other blood-borne pathogens and blood-related diseases.

NSR-seq transcriptional profiling enables identification of a gene signature of Plasmodium falciparum parasites infecting children

PubMed Central

Vignali, Marissa; Armour, Christopher D.; Chen, Jingyang; Morrison, Robert; Castle, John C.; Biery, Matthew C.; Bouzek, Heather; Moon, Wonjong; Babak, Tomas; Fried, Michal; Raymond, Christopher K.; Duffy, Patrick E.

2011-01-01

Malaria caused by Plasmodium falciparum results in approximately 1 million annual deaths worldwide, with young children and pregnant mothers at highest risk. Disease severity might be related to parasite virulence factors, but expression profiling studies of parasites to test this hypothesis have been hindered by extensive sequence variation in putative virulence genes and a preponderance of host RNA in clinical samples. We report here the application of RNA sequencing to clinical isolates of P. falciparum, using not-so-random (NSR) primers to successfully exclude human ribosomal RNA and globin transcripts and enrich for parasite transcripts. Using NSR-seq, we confirmed earlier microarray studies showing upregulation of a distinct subset of genes in parasites infecting pregnant women, including that encoding the well-established pregnancy malaria vaccine candidate var2csa. We also describe a subset of parasite transcripts that distinguished parasites infecting children from those infecting pregnant women and confirmed this observation using quantitative real-time PCR and mass spectrometry proteomic analyses. Based on their putative functional properties, we propose that these proteins could have a role in childhood malaria pathogenesis. Our study provides proof of principle that NSR-seq represents an approach that can be used to study clinical isolates of parasites causing severe malaria syndromes as well other blood-borne pathogens and blood-related diseases. PMID:21317536

Evaluation of a malaria antibody ELISA and its value in reducing potential wastage of red cell donations from blood donors exposed to malaria, with a note on a case of transfusion-transmitted malaria.

PubMed

Chiodini, P L; Hartley, S; Hewitt, P E; Barbara, J A; Lalloo, K; Bligh, J; Voller, A

1997-01-01

Blood donations are often wasted for lack of a satisfactory procedure to evaluate donors potentially exposed to malaria. We evaluated a commercial ELISA for the detection of antibodies to malaria and compared it with an immunofluorescent antibody test (IFAT). When 5,311 sera from routine non-exposed donors were tested, 24 (0.45%) were positive by the ELISA, using a Plasmodium falciparum antigen. Seventeen were subjected to confirmatory testing but none were positive by IFAT. Of 1,000 donors potentially exposed in endemic areas 15 (1.5%) were repeatably reactive by ELISA. 10 of these were tested by IFAT and 2 were positive. When 150 patients attending the Hospital for Tropical Diseases in London with acute malaria were tested, 73% of those infected with P. falciparum were repeatably reactive for malarial antibodies by ELISA and 56% with Plasmodium vivax. Of 88 stored clinical sera tested by both IFAT and ELISA 56 were positive by IFAT and of these 52 (93 degrees/0) were positive by ELISA. The ELISA is sufficiently sensitive and specific to screen at-risk donors. Its use could safely retrieve 40,000 red cell units currently discarded each year in Great Britain.

Plasmodium vivax: modern strategies to study a persistent parasite's life cycle.

PubMed

Galinski, Mary R; Meyer, Esmeralda V S; Barnwell, John W

2013-01-01

Plasmodium vivax has unique attributes to support its survival in varying ecologies and climates. These include hypnozoite forms in the liver, an invasion preference for reticulocytes, caveola-vesicle complex structures in the infected erythrocyte membrane and rapidly forming and circulating gametocytes. These characteristics make this species very different from P. falciparum. Plasmodium cynomolgi and other related simian species have identical biology and can serve as informative models of P. vivax infections. Plasmodium vivax and its model parasites can be grown in non-human primates (NHP), and in short-term ex vivo cultures. For P. vivax, in the absence of in vitro culture systems, these models remain highly relevant side by side with human clinical studies. While post-genomic technologies allow for greater exploration of P. vivax-infected blood samples from humans, these come with restrictions. Two advantages of NHP models are that infections can be experimentally tailored to address hypotheses, including genetic manipulation. Also, systems biology approaches can capitalise on computational biology combined with set experimental infection periods and protocols, which may include multiple sampling times, different types of samples, and the broad use of "omics" technologies. Opportunities for research on vivax malaria are increasing with the use of existing and new methodological strategies in combination with modern technologies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Overproduction, purification and crystallization of a chondroitin sulfate A-binding DBL domain from a Plasmodium falciparum var2csa-encoded PfEMP1 protein

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

Higgins, Matthew K., E-mail: mkh20@cam.ac.uk

A chondroitin sulfate A-binding DBL important in placental malaria has been overproduced, purified and crystallized. Diffraction data were collected to 1.9 Å resolution. The PfEMP1 proteins of the malaria parasite Plasmodium falciparum are inserted into the membrane of infected red blood cells, where they mediate adhesion to a variety of human receptors. The DBL domains of the var2csa-encoded PfEMP1 protein play a critical role in malaria of pregnancy, tethering infected cells to the surface of the placenta through interactions with the glycosaminoglycan carbohydrate chondroitin sulfate A (CSA). A CSA-binding DBL domain has been overproduced in a bacterial expression system, purifiedmore » and crystallized. Native data sets extending to 1.9 Å resolution have been collected and phasing is under way.« less

Multiscale simulation of red blood cell aggregation

NASA Astrophysics Data System (ADS)

Bagchi, P.; Popel, A. S.

2004-11-01

In humans and other mammals, aggregation of red blood cells (RBC) is a major determinant to blood viscosity in microcirculation under physiological and pathological conditions. Elevated levels of aggregation are often related to cardiovascular diseases, bacterial infection, diabetes, and obesity. Aggregation is a multiscale phenomenon that is governed by the molecular bond formation between adjacent cells, morphological and rheological properties of the cells, and the motion of the extra-cellular fluid in which the cells circulate. We have developed a simulation technique using front tracking methods for multiple fluids that includes the multiscale characteristics of aggregation. We will report the first-ever direct computer simulation of aggregation of deformable cells in shear flows. We will present results on the effect of shear rate, strength of the cross-bridging bonds, and the cell rheological properties on the rolling motion, deformation and subsequent breakage of an aggregate.

21 CFR 864.7100 - Red blood cell enzyme assay.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Red blood cell enzyme assay. 864.7100 Section 864... enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure the activity in... kinase or 2,3-diphosphoglycerate. A red blood cell enzyme assay is used to determine the enzyme defects...

21 CFR 864.7100 - Red blood cell enzyme assay.

Code of Federal Regulations, 2014 CFR

2014-04-01

... enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure the activity in... kinase or 2,3-diphosphoglycerate. A red blood cell enzyme assay is used to determine the enzyme defects... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Red blood cell enzyme assay. 864.7100 Section 864...

21 CFR 864.7100 - Red blood cell enzyme assay.

Code of Federal Regulations, 2013 CFR

2013-04-01

... enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure the activity in... kinase or 2,3-diphosphoglycerate. A red blood cell enzyme assay is used to determine the enzyme defects... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Red blood cell enzyme assay. 864.7100 Section 864...

21 CFR 864.7100 - Red blood cell enzyme assay.

Code of Federal Regulations, 2012 CFR

2012-04-01

... enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure the activity in... kinase or 2,3-diphosphoglycerate. A red blood cell enzyme assay is used to determine the enzyme defects... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Red blood cell enzyme assay. 864.7100 Section 864...

Gamma Interferon Production Is Critical for Protective Immunity to Infection with Blood-Stage Plasmodium berghei XAT but Neither NO Production nor NK Cell Activation Is Critical

PubMed Central

Yoneto, Toshihiko; Yoshimoto, Takayuki; Wang, Chrong-Reen; Takahama, Yasuhiro; Tsuji, Moriya; Waki, Seiji; Nariuchi, Hideo

1999-01-01

We have examined the roles of gamma interferon (IFN-γ), nitric oxide (NO), and natural killer (NK) cells in the host resistance to infection with the blood-stage malarial parasite Plasmodium berghei XAT, an irradiation-induced attenuated variant of the lethal strain P. berghei NK65. Although the infection with P. berghei XAT enhanced NK cell lytic activity of splenocytes, depletion of NK1.1+ cells caused by the treatment of mice with anti-NK1.1 antibody affected neither parasitemia nor IFN-γ production by their splenocytes. The P. berghei XAT infection induced a large amount of NO production by splenocytes during the first peak of parasitemia, while P. berghei NK65 infection induced a small amount. Unexpectedly, however, mice deficient in inducible nitric oxide synthase (iNOS−/−) cleared P. berghei XAT after two peaks of parasitemia were observed, as occurred for wild-type control mice. Although the infected iNOS−/− mouse splenocytes did not produce a detectable level of NO, they produced an amount of IFN-γ comparable to that produced by wild-type control mouse splenocytes, and treatment of these mice with neutralizing anti-IFN-γ antibody led to the progression of parasitemia and fatal outcome. CD4−/− mice infected with P. berghei XAT could not clear the parasite, and all these mice died with apparently reduced IFN-γ production. Furthermore, treatment with carrageenan increased the susceptibility of mice to P. berghei XAT infection. These results suggest that neither NO production nor NK cell activation is critical for the resistance to P. berghei XAT infection and that IFN-γ plays an important role in the elimination of malarial parasites, possibly by the enhancement of phagocytic activity of macrophages. PMID:10225894

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

PubMed

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

2015-01-01

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

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

PubMed Central

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

2015-01-01

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

A Phase II pilot trial to evaluate safety and efficacy of ferroquine against early Plasmodium falciparum in an induced blood-stage malaria infection study.

PubMed

McCarthy, James S; Rückle, Thomas; Djeriou, Elhadj; Cantalloube, Cathy; Ter-Minassian, Daniel; Baker, Mark; O'Rourke, Peter; Griffin, Paul; Marquart, Louise; Hooft van Huijsduijnen, Rob; Möhrle, Jörg J

2016-09-13

Ferroquine (SSR97193) is a candidate anti-malarial currently undergoing clinical trials for malaria. To better understand its pharmacokinetic (PK) and pharmacodynamic (PD) parameters the compound was tested in the experimentally induced blood stage malaria infection model in volunteers. Male and non-pregnant female aged 18-50 years were screened for this phase II, controlled, single-centre clinical trial. Subjects were inoculated with ~1800 viable Plasmodium falciparum 3D7A-infected human erythrocytes, and treated with a single-dose of 800 mg ferroquine. Blood samples were taken at defined time-points to measure PK and PD parameters. The blood concentration of ferroquine and its active metabolite, SSR97213, were measured on dry blood spot samples by ultra-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS). Parasitaemia and emergence of gametocytes were monitored by quantitative PCR. Safety was determined by recording adverse events and monitoring clinical laboratory assessments during the course of the study. Eight subjects were enrolled into the study, inoculated with infected erythrocytes and treated with 800 mg ferroquine. Ferroquine was rapidly absorbed with maximal exposure after 4-8 and 4-12 h exposure for SSR97213. Non-compartmental PK analysis resulted in estimates for half-lives of 10.9 and 23.8 days for ferroquine and SSR97213, respectively. Parasite clearance as reported by parasite reduction ratio was 162.9 (95 % CI 141-188) corresponding to a parasite clearance half-life of 6.5 h (95 % CI: 6.4-6.7 h). PK/PD modelling resulted in a predicted minimal parasiticidal concentration of 20 ng/mL, and the single dosing tested in this study was predicted to maintain an exposure above this threshold for 454 h (37.8 days). Although ferroquine was overall well tolerated, transient elevated transaminase levels were observed in three subjects. Paracetamol was the only concomitant treatment among the two out of these three subjects

Use of Blood Smears and Dried Blood Spots for Polymerase Chain Reaction-Based Detection and Quantification of Bacterial Infection and Plasmodium falciparum in Severely Ill Febrile African Children.

PubMed

Wihokhoen, Benchawan; Dondorp, Arjen M; Turner, Paul; Woodrow, Charles J; Imwong, Mallika

2016-02-01

Molecular approaches offer a means of testing archived samples stored as dried blood spots in settings where standard blood cultures are not possible. Peripheral blood films are one suggested source of material, although the sensitivity of this approach has not been well defined. Thin blood smears and dried blood spots from a severe pediatric malaria study were assessed using specific polymerase chain reaction (PCR) primers to detect non-typhoidal Salmonella (NTS; MisL gene), Streptococcus pneumoniae (lytA), and Plasmodium falciparum (18S rRNA). Of 16 cases of NTS and S. pneumoniae confirmed on blood culture, none were positive by PCR using DNA extracts from blood films or dried blood spots. In contrast, four of 36 dried blood spots and two of 178 plasma samples were PCR positive for S. pneumoniae, despite negative bacterial blood cultures, suggesting false positives. Quantitative assessment revealed that the effective concentration of P. falciparum DNA in blood films was three log orders of magnitude lower than for dried blood spots. The P. falciparum kelch13 gene could not be amplified from blood films. These findings question the value of blood PCR-based approaches for detection of NTS and S. pneumoniae, and show that stored blood films are an inefficient method of studying P. falciparum. © The American Society of Tropical Medicine and Hygiene.

Larval diet affects mosquito development and permissiveness to Plasmodium infection.

PubMed

Linenberg, Inbar; Christophides, George K; Gendrin, Mathilde

2016-12-02

The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke's Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing.

Seasonality, Blood Feeding Behavior, and Transmission of Plasmodium Falciparum by Anopheles Arabiensis after an Extended Drought In Southern Zambia

PubMed Central

Thuma, Philip E.; Mharakurwa, Sungano; Norris, Douglas E.

2014-01-01

Transmission of Plasmodium falciparum is hyperendemic in southern Zambia. However, no data on the entomologic aspects of malaria transmission have been published from Zambia in more than 25 years. We evaluated seasonal malaria transmission by Anopheles arabiensis and An. funestus s.s. and characterized the blood feeding behavior of An. arabiensis in two village areas. Transmission during the 2004–2005 rainy season was nearly zero because of widespread drought. During 2005–2006, the estimated entomologic inoculation rate values were 1.6 and 18.3 infective bites per person per transmission season in each of the two village areas, respectively. Finally, with a human blood index of 0.923, An. arabiensis was substantially more anthropophilic in our study area than comparable samples of indoor-resting An. arabiensis throughout Africa and was the primary vector responsible for transmission of P. falciparum. PMID:17297034

Clinical, genetic and fertility studies of Indians with beta S-globin gene and the influence of Hb S on Plasmodium falciparum malaria infection.

PubMed

Joishy, S K; Hassan, K; Lopes, M; Lie-Injo, L E

1988-01-01

Clinical studies were carried out on mild Indian sickle cell anaemia in Malaysia, and genetic and fertility studies were carried out on 101 families with and without sickle-cell haemoglobin (Hb S). The Indian sickle cell anaemia patients reached adulthood, and pregnancies and deliveries were uneventful without blood transfusion. There was no foetal wastage and the number of children produced was not significantly different from that in families without Hb S. 28 Indian patients hospitalized with Plasmodium falciparum malaria infection were also examined for their beta S genotype. P. falciparum malaria infection occurred much more frequently in individuals without Hb S than in Hb S carriers.

Modulatory effect of crude aqueous extract of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Higher Basidiomycetes), on hematological and antioxidant indices in Plasmodium berghei-infected mice.

PubMed

Oluba, Olarewaju M; Adebisi, Kayode E; Eidangbe, George O; Odutuga, Adewale A; Onyeneke, E Chukwu

2014-01-01

Hematological and antioxidant effects of the aqueous extract of fruiting bodies of Ganoderma lucidum were evaluated in Plasmodium berghei-infected mice. Extract was administered at doses of 100, 250, and 500 mg/kg body weight by an intragastric tube once daily for 14 d starting from the fourth day after parasite inoculation. At the end of treatment period, mice in each group were sacrificed and blood was collected for hematological and biochemical analyses. A significant (P<0.05) decrease was observed in serum malondialdehyde content with a corresponding significant (P<0.05) increase in superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and glucose 6-phosphate dehydrogenase activities in the extract-treated groups compared to the infected but untreated group. The results obtained suggest that crude aqueous extract of G. lucidum fruiting bodies possesses potent antioxidant activity that protects hemoglobin against Plasmodium-induced oxidative damage. These findings seem to justify the use of the plant in traditional African and Chinese medicine as an anti-inflammatory and antimicrobial agent.

Targeting Plasmodium PI(4)K to eliminate malaria.

PubMed

McNamara, Case W; Lee, Marcus Cs; Lim, Chek Shik; Lim, Siau Hoi; Roland, Jason; Simon, Oliver; Yeung, Bryan Ks; Chatterjee, Arnab K; McCormack, Susan L; Manary, Micah J; Zeeman, Anne-Marie; Dechering, Koen J; Kumar, Tr Santha; Henrich, Philipp P; Gagaring, Kerstin; Ibanez, Maureen; Kato, Nobutaka; Kuhen, Kelli L; Fischli, Christoph; Nagle, Advait; Rottmann, Matthias; Plouffe, David M; Bursulaya, Badry; Meister, Stephan; Rameh, Lucia; Trappe, Joerg; Haasen, Dorothea; Timmerman, Martijn; Sauerwein, Robert W; Suwanarusk, Rossarin; Russell, Bruce; Renia, Laurent; Nosten, Francois; Tully, David C; Kocken, Clemens Hm; Glynne, Richard J; Bodenreider, Christophe; Fidock, David A; Diagana, Thierry T; Winzeler, Elizabeth A

2013-12-12

Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.

Targeting Plasmodium PI(4)K to eliminate malaria

NASA Astrophysics Data System (ADS)

McNamara, Case W.; Lee, Marcus C. S.; Lim, Chek Shik; Lim, Siau Hoi; Roland, Jason; Nagle, Advait; Simon, Oliver; Yeung, Bryan K. S.; Chatterjee, Arnab K.; McCormack, Susan L.; Manary, Micah J.; Zeeman, Anne-Marie; Dechering, Koen J.; Kumar, T. R. Santha; Henrich, Philipp P.; Gagaring, Kerstin; Ibanez, Maureen; Kato, Nobutaka; Kuhen, Kelli L.; Fischli, Christoph; Rottmann, Matthias; Plouffe, David M.; Bursulaya, Badry; Meister, Stephan; Rameh, Lucia; Trappe, Joerg; Haasen, Dorothea; Timmerman, Martijn; Sauerwein, Robert W.; Suwanarusk, Rossarin; Russell, Bruce; Renia, Laurent; Nosten, Francois; Tully, David C.; Kocken, Clemens H. M.; Glynne, Richard J.; Bodenreider, Christophe; Fidock, David A.; Diagana, Thierry T.; Winzeler, Elizabeth A.

2013-12-01

Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.

[Therapeutic response of Plasmodium vivax to chloroquine in Bolivia].