Molecular detection of the infectivity status of Anopheles gambiae stricto lacto in Osun State, Nigeria

Abstract

The present study reports the infectivity of An. gambiae s.l with sporozoite of Plasmodium. falciparum. Adult mosquitoes were caught quarterly in three communities across the state between 1800hr – 0600hr using the Centre for Disease Control light trap and 0600hr – 0700hr for pyrethrum spray catch (PSC) using protocol by the WHO and identified using morphological keys. Molecular analysis for sibling species identification was conducted using Polymerase Chain Reaction. The CDC light trap had a total of ninety (90) catches while the PSC had a relatively low number (1) of catch. A total of 4 samples were positive for P. falciparum. Ido-Osun 2 (50%) recorded the highest infectivity status as compared to Inisa 1(50%) and Ife 1 (50%). Infectivity was found in the first, second and third quarters respectively. The outdoor catch had the highest number of sporozoites detected across the study areas as compared to the indoor catch (p = 0.59; P > 0.05). Similarly, 1 (33.3%) sporozoite was detected in the outdoor catches across all the study areas. The only sporozoite detected indoor was found at Ido-Osun. No sample was positive for P. vivax sporozoite across the study areas. The present study therefore suggests the possibility of an ongoing transmission of falciparum malaria in the state. Therefore, the need to devise proactive control and preventive measures targeted at containing the transmission.