Anophelines in the state of Acre, Brazil, infected with Plasmodium falciparum, P. vivax, the variant P. vivax VK247 and P. malariae

Abstract

Anophelines collected indoors and in the peri-domiciliary area in 3 localities in the Amazon region, state of Acre, Brazil, from August 1990 to January 1991 were examined by enzyme-linked immunosorbent assay (ELISA) using specific monoclonal antibodies directed against the repeats of the circumsporozoite proteins of Plasmodium falciparum, P. Vivax, P. vivax V247, and P. malariae. Of the 3056 specimens collected, 2610 were Anopheles oswaldoi, 362 A. deaneorum, 60 A. triannulatus and 24 were A. darlingi. The infection rates of A. oswaldoi were 3·41% for P. falciparum, 2·26% for P. vivax, 1·22 for P. vivax VK247, and 0·42% for P. malariae. For A. deaneorum, the infection rates were 2·76% for P. falciparum, 0·55% for P. vivax, and 0·82% for P. vivax VK247. All samples of the other 2 species collected ( A. triannulatus and A. darlingi) were negative in the ELISA. There were certain differences in the anopheline distribution and infection rates between these localities, and in one only A. oswaldoi was found to be infected. These results strongly point to A. oswaldoi as the main malaria vector in the region. No difference was found between the potential vectors of P. vivax and P. vivax VK247. The significance of these findings for malaria control is discussed.