Plasmodium simium in the Atlantic forest of Rio de Janeiro: The Brazilian zoonotic malaria

In Brazil, almost all cases of malaria (> 99%) are concentrated in the Amazon region, the endemic area of the country, and individuals with malaria in non-endemic regions are rare. Malaria transmission has been essentially eliminated in southern and southeastern Brazil (where the Rio de Janeiro State is located), but outbreaks of autochthonous malaria have been reported associated with the Atlantic forest ecosystem, particularly in its mountain valleys. The accu-mulation of water in bromeliads, abundant plants in the Atlantic forest biome, is the breeding site for the main mosquito vector Anopheles (Kerteszia) cruzii. This vector is capable of taking blood meals both at the tree canopy and at ground level, a behavior that allows transmission between non-human primates and humans. Thanks to this peculiarity, autochthonous cases in the region are known as Atlantic forest malaria or bromeliad malaria. In the Rio de Janeiro state, Plasmodium simium, a species previously considered specific to monkeys, was confirmed as the causal agent of zoonotic malaria detected in the region from the analysis of human cases from 2015 and 2016. The mosquito vector becomes infected in non-human primates, which act as reservoirs of the parasite, and transmits it to humans, who present malaria with low parasitemia and no severity. The identification of malaria transmission by P. simium places the Brazilian Atlantic forest as the second hotspot of zoonotic malaria worldwide. (c) 2023 l'Academie nationale de medecine. Published by Elsevier Masson SAS. All rights reserved.