Malaria
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Hover over keys for definitions:Among the human malarias, P. falciparum is the most virulent and associated with the largest number of deaths. Chimpanzees are hosts to a closely related pathogen (P. reichenowii) and can be experimentally infected with human P. falciparum without exhibiting any symptoms of severe disease. Conversely, an old study indicated that humans could not be infected by P. reichenowii. One study comparing the merozoite stage EBA-175 receptors of these two pathogens and their respective binding preferences to host target molecules on red blood cells indicates that human P. falciparum evolved to exploit the uniquely human sialic acid content of target attachment molecules - possibly explaining the difference in virulence of P. falciparum in humans and apes. More recent studies show that all extant P. falciparum strains are likely derived from a single "great ape" to human transfer event. A likely explanation is that the loss of expression of the Neu5Gc sialic acid in hominin ancestors made them partially or completely resistant to the extant P. reichenowii, and that one strain later evolved to bind the Neu5Ac-rich erythrocytes of humans, eventually becoming P. falciparum
References
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Evolutionary history of human Plasmodium vivax revealed by genome-wide analyses of related ape parasites, , Proceedings of the National Academy of Sciences, 2018/08/15, (2018)
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Origin of the human malaria parasite Plasmodium falciparum in gorillas, , Nature, 2010/09/23, Volume 467, Issue 7314, p.420 - 425, (2010)
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Human-specific evolution of sialic acid targets: explaining the malignant malaria mystery?, , Proc Natl Acad Sci U S A, Sep 1, Volume 106, Number 35, p.14739-40, (2009)
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The origin of malignant malaria, , 2009/09/01, Volume 106, Issue 35, p.14902 - 14907, (2009)
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Evolution of human-chimpanzee differences in malaria susceptibility: relationship to human genetic loss of N-glycolylneuraminic acid, , Proc Natl Acad Sci U S A, Sep 6, Volume 102, Number 36, p.12819-24, (2005)