Malaria outside the Amazon region: natural Plasmodium infection in anophelines collected near an indigenous village in the Vale do Rio Branco, Itanhaém, SP, Brazil.

ABSTRACT

A few cases of Plasmodium vivax malaria in which anophelines of subgenus Kerteszia were incriminated as vectors have been reported outside the Amazon region, in the Atlantic Forest. This study was carried out near an indigenous Guarani village in the Curucutu reserve, an environmental protection area in the municipality of Itanhaém in the state of São Paulo, Brazil, on November 30, 2009, February 18, 2010, April 29, 2010 and May 26, 2010. Mosquitoes were collected along the route to the Guarani village where the edge of the Branco river floodplain meets the forests on the mountain slopes. Adult forms were collected with CO(2)-baited CDC traps and Shannon traps from twilight to 1000 P.M. Anopheles cruzii predominated in both traps. The other species collected in the CDC traps were An. pseudomaculipes/maculipes, An. fluminensis and An. mediopunctatus/forattinii/costai. In addition to the latter three species, An. apicimacula/intermedius and An. strodei were also found in the Shannon traps. All but An. cruzii and An. strodei belong to subgenus Anopheles. A total of 506 mosquitoes were assayed by PCR to detect natural infection by Plasmodium species. In the CDC traps, An. fluminensis and An. pseudomaculipes/maculipes were positive for Plasmodium malariae, while in the Shannon traps An. pseudomaculipes/maculipes was positive for Plasmodium vivax and Plasmodium malariae and An. cruzii was positive for P. malariae, resulting in a minimum infection rate of 0.24%. Our findings suggest that An. cruzii may be incriminated in the transmission of malaria between monkeys and humans, as this species was found to be infected by P. malariae. They also highlight the need for an understanding of the role of anophelines from outside subgenus Kerteszia in the transmission of malaria in the Atlantic Forest, as these were also found to be naturally infected by P. vivax and P. malariae.