Abstract
BackgroundIndividuals living in malaria-endemic regions may be exposed to more than one Plasmodium species; there is paucity of data on the distribution of the different species of Plasmodium in affected populations, in part due to the diagnostic method of microscopy, which cannot easily differentiate between the species. Sero-epidemiological data can overcome some of the shortcomings of microscopy.MethodsThe specificity of IgG antibodies to recombinant merozoite surface protein 1 (MSP-119) derived from four human Plasmodium species (Plasmodiumfalciparum, Plasmodiumvivax, Plasmodiummalariae, Plasmodiumovale) was investigated using competition enzyme-linked immunosorbent assay. Subsequently, these antigens were used to determine the exposure prevalence to the different Plasmodium species in serum samples of participants. One-hundred individuals, aged five-18 years, from each of the three Plasmodium meso-endemic Zimbabwean villages (Burma Valley, Mutoko, Chiredzi) were recruited in the study.ResultsThe study demonstrated that the host serum reactivity to MSP-119 antigens was species-specific and that no cross-reactivity occurred. The overall prevalence of antibody response to MSP-119 antigens was 61 % in Burma Valley, 31 % in Mutoko and 32 % in Chiredzi. Single species IgG responses to MSP-119 were most frequent against P. falciparum, followed by P. malariae and P. ovale, with responses to P. vivax being the least prevalent. Interestingly, 78–87 and 50 % of sera with IgG responses to P. malariae and P. ovale MSP-119, respectively, also had IgG specific response for P. falciparum MSP-119 antigens, indicating that exposure to these species is a common occurrence in these populations. Single species IgG responses to the non-falciparum species were at a very low frequency, ranging between 0 and 13 % for P. malariae.ConclusionsThere is evidence of a higher exposure to the non-falciparum parasite species than previously reported in Zimbabwe. The recombinant MSP-119 antigens could be used as additional diagnostic tools in antibody assays for the detection of exposure to the different Plasmodium species. The results also introduce an interesting concept of the co-infection of non-falciparum Plasmodium almost always with P. falciparum, which requires further validation and mechanistic studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1325-3) contains supplementary material, which is available to authorized users.
Highlights
Individuals living in malaria-endemic regions may be exposed to more than one Plasmodium species; there is paucity of data on the distribution of the different species of Plasmodium in affected populations, in part due to the diagnostic method of microscopy, which cannot differentiate between the species
As a positive control, when P. falciparum merozoite surface protein (MSP)-119 antigen was coated onto microtitre plates, sera pre-incubated with P. falciparum MSP-119, were inhibited from binding in a dose-dependent manner (Fig. 1)
To assess anti-MSP-119 cross-reactivity, P. falciparum MSP-119 antigen was coated onto microtitre plates and dual specificity sera were pre-incubated with increasing concentrations of the heterologous P. malariae or P. ovale MSP-119 antigens
Summary
Individuals living in malaria-endemic regions may be exposed to more than one Plasmodium species; there is paucity of data on the distribution of the different species of Plasmodium in affected populations, in part due to the diagnostic method of microscopy, which cannot differentiate between the species. Microscopic examination has several limitations such as the inability to detect low levels of parasitaemia, and the difficulty in species differentiation owing to subtle differences in the morphology of blood stage parasites [4]. This results in the species of Plasmodium causing disease being rarely reported, and almost all cases of malaria are attributed to P. falciparum, the species causing the most serious form of malaria [3]. There is an urgent need for additional diagnostic tools [2,3,4] capable of rapid detection of all four infecting Plasmodium species for effective treatment and control of malaria
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
