Seroepidemiology of Plasmodium species infections in Zimbabwean population

Diop

et al. 2017

Malar J

BackgroundMalaria in Senegal is due essentially to infections by Plasmodium falciparum and, to a lesser extent to Plasmodium malariae and Plasmodium ovale. By the use of molecular methods, detection of Plasmodium vivax has been recently reported in the region of Kedougou, raising the question of appraisal of its potential prevalence in this setting.MethodsA retrospective serological study was carried out using 188 samples taken from 2010 to 2011 in a longitudinal school survey during which 48 asymptomatic children (9–11 years) were recruited. Four collections of samples collected during two successive dry and rainy seasons were analysed for antibody responses to P. vivax and P. falciparum. Recombinant P. falciparum and P. vivax MSP1 antigens and total P. falciparum schizont lysate from African 07/03 strain (adapted to culture) were used for ELISA. Nested PCR amplification was used for molecular detection of P. vivax.ResultsA surprising high prevalence of IgG responses against P. vivax MSP1 was evidenced with 53% of positive samples and 58% of the individuals that were found positive to this antigen. There was 77% of responders to P. falciparum outlined by 63% of positive samples. Prevalence of responders did not differ as function of seasons. Levels of antibodies to P. falciparum fluctuated with significant increasing between dry and rainy season (P < 0.05), contrary to responses to P. vivax. There was a significant reciprocal relationship (P < 10−3) between antibody responses to the different antigens, but with weak coefficient of correlation (Rho around 0.3) underlining a variable profile at the individual level. Clear molecular signature was found in positive IgG to P. vivax msp1 samples by PCR.ConclusionThis cross-sectional longitudinal study highlights the unexpected high circulation of P. vivax in this endemic area. Sero-immunology and molecular methods are powerful additive tools to identify endemic sites where relevant control measures have to be settled and monitored.

Section: Discussionmentioning

confidence: 99%

Unexpected high circulation of Plasmodium vivax in asymptomatic children from Kédougou, southeastern Senegal

Diop

et al. 2017

Malar J

“…erefore, this method is intrinsically less suited to the rapid detection of suspected current infection in order to inform effective treatment and more beneficial to malaria epidemiological studies and surveillance programs [23] ( Table 1). For instance, competitive enzyme-linked immunosorbent assay (ELISA) can be used as a diagnostic tool to determine in a particular malaria-endemic study site the species specificity of IgG antibody responses, and [30]. Serological responses generally increase with exposure, and thus, as an indirect correlate, with age, in regions of stable malaria transmission.…”

Section: Immunology-based Diagnosismentioning

confidence: 99%

Improving Accuracy of Malaria Diagnosis in Underserved Rural and Remote Endemic Areas of Sub-Saharan Africa: A Call to Develop Multiplexing Rapid Diagnostic Tests

Makanjuola

Taylor‐Robinson

2020

Scientifica

Clinical infection with malaria, caused by parasites of the genus Plasmodium, is considered a serious medical condition with the potential to become a life-threatening emergency. This is especially relevant to low-income countries in tropical and subtropical regions of the world where high rates of malaria-related morbidity and mortality are recorded. As a means to combat this major global public health threat, rapid and effective diagnosis remains the frontline action to initiate a timely and appropriate medical intervention. From all the approaches to parasite detection, rapid diagnostic tests, so-called RDTs, are the easiest to use and most cost-effective. However, some of the limitations inherent in this methodology could hinder effective patient treatment. A primary drawback is that the vast majority of commercially available RDTs detect only one of the five species of human malaria, P. falciparum. While this is the main cause of infection in many areas, it excludes the possibility of infection with another parasite (P. vivax, P. ovale, P. malariae, and P. knowlesi) or of mixed infections containing different species. Hence, a diagnosis of non-P. falciparum malaria is missed. In turn, in resource-constrained settings where optimal microscopy is not available, a misdiagnosis of bacterial infection based on signs and symptoms alone often results in an inappropriate prescription of antibiotics. Here, we discuss how effective diagnosis of malaria and indiscriminate use of antibiotics in sub-Saharan Africa, a hot spot for P. falciparum transmission, may both be addressed by the development of innovative multiplexing RDTs that detect two or more species of Plasmodium.

“…During a bed net intervention study in a high malaria transmission region of northern Mozambique [ 41 ], numerous samples from individuals were assayed and found to have very high IgG antibody responses to multiple malaria species MSP1 19 antigens, including the P. vivax antigen. These samples and samples from two low transmission regions in a multiplex assay format to expand on the MSP1 19 competition ELISA studies of Amanfo et al [ 42 ].…”

Section: Introductionmentioning

confidence: 99%

Specificity of the IgG antibody response to Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale MSP119 subunit proteins in multiplexed serologic assays

Priest

Pluciński

Huber

et al. 2018

Malar J

BackgroundMultiplex bead assays (MBA) that measure IgG antibodies to the carboxy-terminal 19-kDa sub-unit of the merozoite surface protein 1 (MSP119) are currently used to determine malaria seroprevalence in human populations living in areas with both stable and unstable transmission. However, the species specificities of the IgG antibody responses to the malaria MSP119 antigens have not been extensively characterized using MBA.MethodsRecombinant Plasmodium falciparum (3D7), Plasmodium malariae (China I), Plasmodium ovale (Nigeria I), and Plasmodium vivax (Belem) MSP119 proteins were covalently coupled to beads for MBA. Threshold cut-off values for the assays were estimated using sera from US citizens with no history of foreign travel and by receiver operator characteristic curve analysis using diagnostic samples. Banked sera from experimentally infected chimpanzees, sera from humans from low transmission regions of Haiti and Cambodia (N = 12), and elutions from blood spots from humans selected from a high transmission region of Mozambique (N = 20) were used to develop an antigen competition MBA for antibody cross-reactivity studies. A sub-set of samples was further characterized using antibody capture/elution MBA, IgG subclass determination, and antibody avidity measurement.ResultsTotal IgG antibody responses in experimentally infected chimpanzees were species specific and could be completely suppressed by homologous competitor protein at a concentration of 10 μg/ml. Eleven of 12 samples from the low transmission regions and 12 of 20 samples from the high transmission area had antibody responses that were completely species specific. For 7 additional samples, the P. falciparum MSP119 responses were species specific, but various levels of incomplete heterologous competition were observed for the non-P. falciparum assays. A pan-malaria MSP119 cross-reactive antibody response was observed in elutions of blood spots from two 20–30 years old Mozambique donors. The antibody response from one of these two donors had low avidity and skewed almost entirely to the IgG3 subclass.ConclusionsEven when P. falciparum, P. malariae, P. ovale, and P. vivax are co-endemic in a high transmission setting, most antibody responses to MSP119 antigens are species-specific and are likely indicative of previous infection history. True pan-malaria cross-reactive responses were found to occur rarely.Electronic supplementary materialThe online version of this article (10.1186/s12936-018-2566-0) contains supplementary material, which is available to authorized users.