Impact of indoor residual spraying using bendiocarb 80% on the composition, abundance and resting habits of malaria vectors in Bahir Dar Zuria district, Ethiopia

Abstract

The reduction of malaria-related mortality and morbidity are attributed to the use of indoor residual spraying and long-lasting insecticidal nets. However, data for the measurable impacts of these vector control intervention tools on entomological indices are either unavailable or not sufficient. The impact of indoor residual spraying using bendiocarb 80% on the composition, abundance and resting habits of malaria vectors was assessed. Mosquitoes were sampled from residential houses using pyrethroid spray catches and CDC light traps. Pit shelter collections were also made from pit shelters constructed under shade trees and in close proximity to nearby indoor collecting houses. Vectors were surveyed and recorded before the application of indoor residual spraying. Descriptive and inferential statistics were used for data analyses. A total of 20,243 mosquitoes were collected and 43.8% and 56.2% of them belong to Anopheles and culicines mosquitoes, respectively. Anopheles arabiensis, An. pharoensis and An. coustani were recorded during the study period. An. arabienesis was the most abundant species (70.2%), while An. coustani was the least abundant (7.9%). Vector population drastically declined after spray. Indoor and outdoor resting habits of An. arabiensis were unaffected by the spray. General estimating equation model analyses showed that all effects or explanatory variables and their sublevels played significant role in the build-up of An. arabiensis mosquito population, except the number of human hosts that slept the previous night in mosquito collection houses. The results indicated that indoor residual spraying using bendiocarb 80% effectively reduced the abundance of malaria vectors without impacting its resting habits.

Key words/phrases: Anopheles mosquito, Ethiopia, Indoor residual spraying, Mosquito abundance.