Biological and genetic characterization of zoonotic malaria parasites in Brazilian non-human primates

In Brazil, most human cases of malaria occur in the legal Amazon. However, autochthonous cases occur occasionally in the Atlantic Forest regions in the South and Southeast of Brazil. We and other researchers have recently shown that these cases are the result of the zoonotic transmission of Plasmodium simium infecting non-human primates (PNHs). Two species of malaria parasites are able to infect PNHs in the Atlantic Forest, P. brasilianum and P. simium, closely related to the parasites that cause human malaria, P. malariae and P. vivax, respectively. Plasmodium brasilianum has a wide geographical distribution, being identified from Central America to the north of Argentina. In addition, this parasite has a wide range of hosts, being able to infect species of all families of Platyrrhini primates. In contrast, P. simium is restricted to the Atlantic Forest of the South and Southeast of Brazil. This parasite is able to infect a restricted number of PNH species, only from the families Atelidae, Cebidae and Pithecidae. Despite the importance of these parasites due to their zoonotic potential, relatively little is known about the prevalence of infection, evolutionary history, how they adapted to the hosts and their potential to cause disease in humans. The genetic proximity between P. brasilianum / P. malariae and P. simium / P. vivax suggests that these pairs of species have recently diverged, despite the direction of host exchange throughout evolution, that is, from man to PNHs or PNHs for Man, has not yet been completely clarified. In addition, the prevalence of these parasites among the various species of HNP and in different regions of the Atlantic Forest remains unknown, making it very unclear the real threat of these parasites to human health. Initially, to reach the objective, a differential diagnosis of P. simium infection will be necessary, using two methodologies, one Nested / PCR RFLP and one Real-time PCR. The first methodology has already been standardized and the second one, which will allow large scale implementation and the correlation with parasitemia of animals is being standardized. In addition, another important aspect for the surveillance of zoonotic malaria is the definition of the species of potential PNH reservoirs of the infection. Thus, after identifying the infection through the differential diagnosis it will be important to verify the presence of the infecting form of the parasite, the gametocytes. In this way it will be possible to clarify the evolution and adaptation of these parasites in the Americas and contribute to the definition of public policies for the prevention and control of extra-Amazonian malaria.

Basic Science
Genetics and Genomics

Feb 2019 — Feb 2023

Brazil