Tekie, Habte (PhD)Kinfe, Esayas2019-04-182023-11-092019-04-182023-11-092018-04-03http://etd.aau.edu.et/handle/123456789/18059Detection and monitoring of insecticide resistance in malaria vectors is crucial and has to be conducted together with other entomological indices for effective vector control. The aim of this study was to identify species composition of Anopheles mosquitoes, behaviour and feasibility of resistance management using rotation of indoor insecticides spray combined with different insecticide impregnated long lasting insecticidal nets. Monthly larvae and adult Anopheles collections were undertaken from May 2013 to June 2015 in Intervention (Jolie) and Control (Gogete) study sites. Identification of Anopheles species were done using morphological keys under a compound microscope as well as 10% of the adult specimens identified as Anopheles gambiae s.l. also subjected for species-specific polymerase chain reaction (PCR) test for sibling species detection. Abdominal status, host and resting preferences, indoor resting density, parity rate, sporozoite rate, man biting rate and entomological inoculation rate were compared among the Intervention (Jolie) and Control (Gogete) study sites to evaluate the impact of the resistance management option used in Intervention study site (Jolie). Besides, An. gambiae s.l. susceptibility tests result carried out every year throughout the study period (in the month of August 2013, 2014, 2015 and 2016) to determine the susceptibility status of An. gambiae s.l. among the Intervention (Jolie) and Control (Gogete) study sites were compared to observe the impact of the resistance management option. To detect the presence of the L1014S and the L1014F kdr mutation a sub-sample of An. arabiensis and An. gambiae were selected from both study sites and tested using adapted versions of the allele-specific polymerase chain reaction (from October 2016 to April 2017). xx A total of 4118 third and fourth instars larvae of Anopheles mosquitoes used for identification, ten in Intervention study site (Jolie) and eleven in Control (Gogete) Anopheles species were identified. Most of Anopheles larvae (27.5%) were collected from marshy breeding site which served as major breeding sites during the study period, followed by irrigation canals (24.5%), rain pools (20.4%), river pockets (17.6%) and ponds (9.9%). In both Intervention (Jolie) and Control (Gogete) study sites the predominant Anopheles species was An. gambiae s.l. which is the main vector in the country. Statistically significant (p<0.05) seasonal variations were observed in the larval collection of Anopheles larvae in Intervention (Jolie) and Control (Gogete) study sites. In line with this a total of 4461 indoor adult female Anopheles were caught of which 1386 (31.1%) from Intervention (Jolie) and 3075 (68.9%) from Control (Gogete) study site. Out of 1386 of female Anopheles mosquitoes caught from Intervention study site (Jolie) An. gambiae s.l. was the predominant species making up 63.9% followed by An. pharoensis 19%. Similarly, out of 3075 of female Anopheles mosquitoes caught in Control study site (Gogete) also An. gambiae s.l. was the predominant species (64%) followed by An. pharoensis (19.1%). Significant (p<0.05) higher number of An. gambiae s.l. and An. pharoensis were collected in the Control (Gogete) than in the Intervention (Jolie) study site. Out of 239 An. gambiae s.l. subjected for PCR sibling species identification 94.1% were found An. arabiensis and 5.9% An. gambiae. At species level in Intervention study site (Jolie) An. gambiae s.l. showed high tendency to feed on bovine 53.8% followed by human 47.9%, unlike in Control (Gogete) An. gambiae s.l. showed high tendency to feed on human 57.1% followed by bovine 40.6%. xxi Statistically significant differences (p<0.05) with low HBI in Intervention (Jolie) than Control (Gogete) study site were observed in An. gambiae s.l. In Intervention (Jolie) the parity rate for An. gambiae s.l. was 45.8 and in Control (Gogete) 52.6 determined. Statistically significant differences (p<0.05) of parity in An. gambiae s.l. and An. pharoensis were observed among the study sites, that is low parity rate found in Intervention (Jolie) than Control (Gogete) study site. The result of sporozoite rate of An. gambiae s.l. in Intervention study site (Jolie) for Pv-210 was (1.1) and in the Control (Gogete) study site (2.8), however for Pf the same result 1.1 detected in both study sites. Statistical significant differences (p<0.05) were observed between Intervention (Jolie) and Control (Gogete) study sites on indoor resting density in both species of An. gambiae s.l. and An. pharoensis, as well as in man-biting rate of An. gambiae s.l. An. gambiae s.l. resistance to DDT, permethrin, malathion, deltamethrin and bendiocarb were detected in both study sites. However, in Intervention (Jolie) An. gambiae s.l. susceptible populations increased in 2016 than 2013, that is significant (p<0.05) improvement on mortality rates due to the tested seven insecticides observed in the Intervention study site (Jolie), while in Control (Gogete) were not. The L1014F kdr mutation in An. arabiensis detected at a relative high frequency 41.7% in Control study site (Gogete) and 35.9% in Intervention (Jolie). Besides, two in Intervention study site (Jolie) and seven in Control (Gogete) heterozygous alleles for L1014F were found in the tested An. arabiensis specimens. However in An. gambiae both xxii kdr mutations were not detected in both study sites. The L1014S kdr alleles were not found in the two study sites. The breeding habitats of Anopheles mosquitoes in the study sites particularly in the dry season were due to human activities rather than environmental causes that require larval control. In the present study An. gambiae was reported for the first time in addition to An. arabiensis in Ethiopia indicating the presence of the highly efficient vector in Ethiopia, thus establishing appropriate control strategy for this species might be necessary. Anopheles gambiae s.l. resistance to DDT, permethrin, malathion, deltamethrin and bendiocarb insecticides in the study sites is worrying. Moreover, West African kdr mutation was found in a higher rate this kdr mutation was related with high levels of both pyrethroid and DDT resistance than East African mutation and furthermore the presence of the incomplete heterozygous state indicates the continuity of kdr incidence shows the needs to urgently implement resistance management strategies. The observed significant reduction of indoor resting density, human host preference, man biting, parity rate as well as increment of susceptibility in An. gambiae s.l. in 2016 compared to that of 2013 clearly indicates the effectiveness of the selected resistance management option applied in Intervention study site (Jolie).enMalaria VectorsInsecticides ResistanceKdr MutationLarval HabitatEthiopiaThesis