Identification of Entomological Drivers for Persisting High Malaria Transmission in Ruangwa District Lindi Region Tanzania

Abstract

High malaria prevalence remains a major problem, despite highcoverage rates of malaria control interventions. The study was carried out to investigate entomological factors responsible for malaria high malaria transmission in Ruangwa district. Three villages were selected from three wards of Ruangwa district; Mnacho and Chienjere. Likangara represented low, Nandagara moderate and Chienjere high malaria prevalence’s. In each village six houses with open eaves were selected for mosquito collection both indoors and outdoors using Human Landing Catches. A total of 2532 female mosquitoes were collected. Malaria vectors constituted 26.66 % (An.gambiae s.l 680(26.35); An.funestus 8 (0.31) and An.coustani s.l 3 (0.11%).while non –malaria vectors accounted for 73.26 (Culex sp. 1854 (73.2%) Aedes sp. 1 (0.03%). Most mosquito abundance was dominant in Chienjere 932 (37%), followed by Likangara 820 (31%) and the least was Nandagara composed of 780 (31%). Out of 688 anophelines subjected for PCR speciation, An.gambiae s.s was relatively higher 297 (43%) compared to An.arabiensis 278 (40%), An.funestus s.s 6 (0.87%) and unamplified 107 (16%). The high abundance of Anopheles mosquitoes was observed in rainy season 553 (95.18%) as compared to dry season 28 (4.82%). An.gambiae s.s and An.arabiensis species are responsible for maintaining high prevalence of malaria even in the absence of other vectors. An. coustani has an epidemiological concern since it is important vector in neighboring country of Kenya and Zambia. The findings provide useful information that would enable to plan and innovative and effective malaria control strategies in the district.