Night-time Biting Behaviour of Malaria Vectors in selected Agrarian Communities of Kano State, Northwest Nigeria

Abstract

Understanding the biting behaviour of vectors is essential for determining their vectorial potential and, hence, their role in disease  transmission. The study was a two-year entomological survey of malaria vectors in three agrarian communities of Kano state designated  as large irrigation (LIC), urban irrigation (UIC) and nonirrigation (NIC) communities. Human-baited Centre for Disease Control (CDC) light  traps collected outdoor and indoor biting adult mosquitoes overnight. The collected female Anophelesspecies were morphologically  identified to the species level using standard keys. A total of six hundred and thirty-seven (637) female Anopheles species were trapped of  which 322 (50.55%) were collected indoors and 315 (49.45%) were collected outdoors. LIC and NIC had more Anopheles mosquitoes  collected outdoors (51.08% and 66.04% respectively) than indoors (48.92% and 33.96% respectively) while UIC had more Anopheles  mosquitoes collected indoors (67.77%) than outdoors (32,23%). Mosquito biting activity was higher in the wet season than in the dry  season but did not differ significantly indoors (F-value = 3.310, p = 0.84) and outdoors (F = 0.651, p = 0.532). Statistical differences were  recorded in the mean outdoor Anopheles abundance (F = 4.51 and p = 0.044) across the communities. Single, bimodal, and multiple biting  peaks were observed in the study. Early biting peaks (1800-1900 hours) were observed outdoors (wet season) in NIC and indoors  in UIC (dry season). The early outdoor biting activities of Anopheles species established in this study suggest the possibility of continued  malarial transmission despite household use of bed nets. This implies that this control measure might be insufficient for malaria control  in the region, and thus integrated methods for controlling malaria vectors should be considered.