Tekie, Habte(PhD)Ejeta, Desta2018-07-202023-11-042018-07-202023-11-042017-06http://etd.aau.edu.et/handle/123456789/9618Malaria is a leading cause of morbidity and mortality in several sub-Saharan African countries. Environmental/ecological changes due to anthropogenic activities are among the determinant factors for malaria transmission. Agricultural practices are among anthropogenic activities that contribute to malaria incidence and transmission. Understanding association of ecological changes due to anthropogenic activities on mosquito species composition, abundance, distribution, dynamics, insecticide resistance and malaria transmission intensity is important to plan and implement effective vector control intervention strategies. Thus, the aim of this study was to investigate species composition, abundance, distribution and infectious rate of Anopheles mosquitoes and their knockdown resistance (kdr) status in relation to agricultural practices. A longitudinal entomological study was conducted from January to December 2015 in Sekoru District, southwestern Ethiopia. Anopheles mosquito larvae and adults were collected using different methods from villages with different agro-ecology. The mosquitoes were identified to species level using standard keys. Molecular identification of Anopheles gambiae complex and detection of knockdown insecticide resistance (kdr) was conducted using species-specific PCR and allele specific PCR techniques. Moreover, Plasmodium circumsporozoite protein was detected for both Plasmodium falciparum and P. vivax using Enzyme-linked Immunosorbent Assay (ELISA). Eight Anopheles mosquito species (Anophelesarabiensis,An. demeilloni, An. squamosus, An. garnhami, An. christyi, An. pretoriensis, An. longipalpis and An. marshallii) were identified, of which An. arabiensis was the predominant species (46.2%; n=715). The highest number of Anopheles mosquitoes (66%; n=1019) was collected from the irrigated village. The xvi infection rate of An. arabiensis was higher in the irrigated village (10.8 infective bites/person/month) as compared to rain fed agriculture practicing village (5.99 infective bites/person/month) and human settlement village (zero infective bite). Anopheles gambiaes.l. larvae were the predominant (57.4%) larval species identified. The highest larval density (2.12 larvae/dip) was recorded from the irrigated village. Only West African kdr mutation (L1014F) was detected with an allelic frequency of 83.88%. The distribution and frequency of kdr allele were significantly associated with study villages (X2=133.85, df=2, P <0.001). The kdr allele frequency was 95%in the irrigated village, 78.87%in village with rain fed agriculture, and 3.89% in the human settlement village. In conclusion, Anopheles mosquito abundance, distribution, infection rate and insecticide resistance were significantly associated with agro-ecology. Agro-ecological practices need to be considered in the management of Anopheles vectors of malaria. Keywords: Anopheles mosquitoes, Agro-ecology, Insecticide resistance, Irrigation, Larval habitats, Malaria, Sekoru DistrictenAnopheles MosquitoesAgro-EcologyInsecticide ResistanceLarval HaIrrigationbitatsMalariaSekoru DistrictThesis