Abstract

Abstract
Background
Vector-borne diseases are the major causes of morbidity and mortality in several regions especially in tropical and subtropical countries. The aim of this study was to compare relative abundance, diversity, Monthly Biting Rates (MBR) and parity rate of onchocerciasis vector collected from four small rivers in Southwest Ethiopia.
Methods
Adult’s Simulium were collected using human landing catch with protected by the MosqTent for four consecutive days per month from 7 a.m. to 6 p.m. from January to December, 2018 at three communities: Dizii, Agalo Ukka and Haro Magela. Ki square test was used to determine association between study site villages and abundances of the Simulium diversity.
Result
During the study period a total of 15, 264 Simulium belong to two species Simulium damnosum Senso Lato and Simulium neivia were collected. The monthly dynamics of Simulium damnosum Senso Lato shows the highest density of flies were observed in August followed by July whereas the lowest were observed in April. On the other hand the highest peak biting hour was observed between 4p.m-6pm, while the lowest hourly activity of the fly was recorded from 7a.m to 8a.m. Furthermore, the highest parity rate was observed 82.2% in July followed by 80.9% in August while the lowest rate was observed 43.7% in January.
Conclusion
This information on onchocerciasis vectors seasonal variation, diversity, parity and biting time are important factors that to be considered for noticeable suggestions in monitoring transmission levels to guide the regional and national onchocerciasis elimination programs in Ethiopia.

Key words: Onchocerciasis, Simulium, Simulium neivia, Vector, Parity