Effects of climatic conditions on the biting density and relative abundance of Simulium damnosum complex in a rural Nigerian farm settlement.

INTRODUCTION AND OBJECTIVE The effect of climatic conditions on the biting density and relative abundance of Simulium damnosum complex at Adani, Nigeria, from August 2010-January 2011 was investigated. MATERIALS AND METHODS The classical method of collecting blackflies for a period of 11 hours using human attractants was employed in the study. Monthly climatic data, such as rainfall, relative humidity and temperature were collected for the period of study. RESULTS Rainfall, relative humidity, temperature, harmattan (cold, dry wind) and deforestation were observed to affect the biting density and relative abundance of blackflies at the site. A total of 548 female adult blackflies were collected. The biting density of the flies ranged from 0.5 Flies/Man/Hour (FMH) in December to 5.5 FMH in January. The relative abundance of the flies ranged from 21 in December to 243 in January. Regression analysis showed that temperature and relative humidity had a positive correlation with relative abundance of Simulium damnosum complex (y=-0.0006x+5.593, r=0.0519) and (y=-0.1213x+78.794, r=0.505), respectively. CONCLUSIONS The risk of getting infected with Onchocerca volvulus increased during the dry season with its associated weather conditions.