First Observations of Plasmodium malariae on the Long-Term Malaria Vector Control Program on Villages of the Balombo Region of Angola

Author(s): Sylvie Manguin, Vincent Foumane, Jean-Claude Toto, Franck Martineaud, Maria Adelaide Dos Santos, Filomeno Fortes, Pierre Carnevale

At the request of the National Malaria Control Program (NMCP), a long-term vector control program was implemented in 2007 in eight villages around the Balombo town (Angola) to compare the efficacy of four methods of indoor vector control. These methods included (1) Long-Lasting deltamethrin Insecticide treated Nets (LLIN PermaNet© 2.0 model or P.2.0); (2) association of P.2.0 and deltamethrin Insecticide Treated Plastic Sheeting (delta-ITPS)-Zero Fly© model; (3) delta-ITPS alone; and (4) 2 rounds of lambdacyhalothrin Inside Residual Spraying (IRS) followed by installation of delta-ITPS. Cross-sectional parasitological surveys (CSS) were done every two months. Plasmodium species determination, parasitemia and gametocytes presence, and evolution in time were analyzed. A total of 190 CSS was done between 2007 and 2011, Plasmodium spp. were observed in 5,431 of the 21,804 TBF done (24.9%). Plasmodium malariae alone was observed in 22 TBF (0.4%) and mixed infections P. falciparum and P. malariae in 44 TBF (0.8%). Our study confirms the presence of P. malariae in Angola, which must be known due to its special clinical impact, quartan fever, kidney failure, chronicity, symptomless carriers, persistence for several years with long term recrudescence and reported cases of resistance to classical ACTs. The prevalence of P. malariae decreased after implementation of vector control methods. The burden of P. malariae needs to be studied to reach the goal of malaria elimination by 2030.