Composition of Indoor Resting Malaria Vectors and their Seasonal Dynamics in Qua'an-Pan LGA, Plateau State, Nigeria

Abstract

Malaria vector surveillance offers data to aid in the successful planning of vector management. Thus, this study aimed to investigate the malaria vectors present indoors in some selected rural communities in Qua’an-Pan Local Government Area, Plateau State, North Central Nigeria. Endophilic mosquitoes were collected in the morning hours using the pyrethrum spray catch technique. Samples were sorted and identified using standard entomological keys. Thereafter, entomological transmission indices were analyzed. A total of 1,499 female Anopheles mosquitoes were collected, which belonged to five species, namely Anopheles gambiae and An. funestus, An. coustani, An. rufipes and An. pretoriensis. The predominant species was Anopheles gambiae, 1,278 (85.26%), followed by An. funestus, 103 (6.87%), while the least abundant was An. pretoriensis 10 (0.67%). Thus, there was a significant difference (c2 = 4008.95, df = 4, P= 0.0001) in mosquito abundance across species. The month of July recorded the highest indoor resting density (IRD) of 11 Anopheles mosquitoes/room/night, while February had the least with 1 mosquito/room/night, and differences between months significantly varied (c2 = 24.26, df = 11, P = 0.012). Similarly, the preponderant man biting rate (MBR) of 4 mosquito bites per person per night was still recorded in July, while the least MBR was recorded in both January and March with about one mosquito bite per person per night, but differences were not significant (c2 = 7.893, df = 11, P = 0.723). The overall one-year MBR was approximately 2 Anopheles mosquito bites/man/ night. Most of the female mosquitoes were fed 649 (43%). A high proportion of freshly fed mosquitoes (43%) indicates an ongoing risk of malaria transmission. The dominance of Anopheles gambiae in the study area necessitates continuous vector monitoring and intentional control measures.