Transmission indices of malaria in Anopheles mosquitoes in an agrarian community adjourning Osogbo, Southwestern Nigeria

Abstract

BACKGROUND OBJECTIVES: Mosquitoes transmit malaria and other infectious diseases. A thorough understanding of the dynamics, biting behavior, and infectiousness of Anopheles vector sporozoites is required to calculate transmission indices and develop effective control tactics. The goal of this study was to identify the mosquito species in a rural settlement near the Osogbo city in southwestern Nigeria, as well as their sources of blood meals and the rate at which sporozoites are formed. METHODS: From June to December 2021, 23 homes in the community were chosen at random to catch adult mosquitos with CDC light traps and pyrethrum spray catches (PSC). Mosquitoes were sorted using morphological criteria, and polymerase chain reaction (PCR) was used to detect the origin of the blood meal, check for the infectivity of sporozoites in the mosquitoes, and calculate the fraction of Anopheles gambiae s.l . collected. RESULTS: Among the 318 mosquitos collected, 185 (58.18 %) were recognized as An. gambiae s.l ., four (1.26 %) as Aedes aegypti , 104 (32.70 %) as Culex quequinfasciatus , and 25 (7.86 %) as Mansonia uniformis . PCR revealed that the specimens of An. gambiae s.l . were 96% An. colluzzi and 4% An. gambiae s.s. An. colluzzi mosquito species only consumed human blood. INTERPRETATION CONCLUSION: The presence of sporozoites in none of the An. gambiae s.l . mosquitoes in the area indicates a low rate of malaria transmission. The anthropoliphic nature of the Anopheles species implies a danger of malaria transmission, despite the fact that none of the people tested positive for sporozoites.