Human migration and the spread of malaria parasites to the New World

Abstract

We examined the mitogenomes of a large global collection of human malaria parasites to explore how and when Plasmodium falciparum and P. vivax entered the Americas. We found evidence of a significant contribution of African and South Asian lineages to present-day New World malaria parasites with additional P. vivax lineages appearing to originate from Melanesia that were putatively carried by the Australasian peoples who contributed genes to Native Americans. Importantly, mitochondrial lineages of the P. vivax-like species P. simium are shared by platyrrhine monkeys and humans in the Atlantic Forest ecosystem, but not across the Amazon, which most likely resulted from one or a few recent human-to-monkey transfers. While enslaved Africans were likely the main carriers of P. falciparum mitochondrial lineages into the Americas after the conquest, additional parasites carried by Australasian peoples in pre-Columbian times may have contributed to the extensive diversity of extant local populations of P. vivax.

Human Plasmodium vivax diversity, population structure and evolutionary origin

“…The highest genetic diversity is again observed in South East Asian P. vivax populations in comparison to the populations of the rest of the world, which argues again the suggested African origin of current human P. vivax. Concerning the colonization of the American continent, results obtained in our study seem to suggest a double origin from Africa (or Europe) and Asia, as already suggested by different studies [34,[37][38][39]. In order to resolve the origin and evolution of these protozoan parasites, more extensive genomic analyses of the genetic diversity and structure of P. vivax are needed, including the study of ancient European P. vivax strains.…”

“…This possibility of introduction from multiple locations has already been mentioned in several recent studies based on the analysis of different kinds of genetic markers [37,38]. Rodrigues et al proposed that African and South East Asian P. vivax populations contributed to the current diversity of P. vivax observed in South America [38]. Carter et al suggested that a large part of the genetic diversity observed today was due to gene flow from Western Pacific to the Americas, which needs to be considered when considering the Australian and Eurasian ancestral origin of three south American native human populations [34].…”

“…These results are consistent with a scenario in which American P. vivax populations were introduced from multiple sources. This possibility of introduction from multiple locations has already been mentioned in several recent studies based on the analysis of different kinds of genetic markers [37,38]. Rodrigues et al proposed that African and South East Asian P. vivax populations contributed to the current diversity of P. vivax observed in South America [38].…”

The genome of the zoonotic malaria parasite Plasmodium simium reveals adaptations to host-switching

“…The observed skew towards higher F ST values when comparing simium and American vivax (Figure 3A) could be a result of an inherent diversity between different American vivax populations potentially stemming from multiple introductions of P. vivax to the American continent 17 . To test if such founder effects and subsequent population bottlenecks could explain the observations, we repeated the F ST analysis using only Mexican vivax samples as American representatives.…”

“…Indeed, present-day P. vivax in South America is closely related to a strain of the parasite present, historically, in Spain 16 . The genetic diversity of extant P. vivax in the Americas suggests multiple post-Columbian colonising events associated with the passage of infected people from various regions throughout the world 17 . There is some evidence to suggest that P. vivax parasites may also have been introduced to South America in pre-Columbian times, and may have contributed to the extensive genetic diversity of the parasite on this continent 17 .…”