BACKGROUND: The Centers for Disease Control and Prevention (CDC) has encouraged states to increase vector control capacity to detect the known Zika-transmitting mosquitoes, Aedes aegypti and albopictus. Aedes albopictus has been identified in many counties in West Virginia (WV), a predominantly rural state with a population of 1.85 million residents. BG Sentinel traps, recommended by CDC to detect Zika-transmitting mosquitoes, have been used in limited capacity in WV, and their effectiveness in the state is largely unknown.
METHODS: Comparative trapping sites were selected based on historical mosquito yield, known presence of Ae. albopictus, population density, and level of security. Data collected from WV’s mosquito surveillance program for 2016, which includes collection events from both the state health department and local health departments, were compiled into an Excel database and analyzed. Species detected, location type, number of traps set, and date of collection data were sorted and compared [MMP1] among BG Sentinel (BGS), CDC Gravid (GT) and CDC Light (LT) traps to identify trap preference of Ae. albopictus females. Odds ratios were computed to compare BGS efficiency to GT and LT based on total number of Ae. albopictus collected.
RESULTS: Combined use of BGS, GT and LT traps for active mosquito surveillance occurred at 5 sites over 22 collection events. The sites included three water treatment facilities, a residential neighborhood, and cemetery. BGS accounted for 12.3% of traps (58/471) set from June to October. Eight hundred and ninety-six female Ae. albopictus were collected during the study period. The highest proportion of Ae. albopictus were collected from a water treatment facility (26.0%, 7/27 total mosquitoes collected) followed by the cemetery (23.6%, 194/823 total mosquitoes collected). GT were 1.9 times as likely and LT were 1.5 times as likely respectively, to trap Ae. albopictus compared to BGS.
CONCLUSIONS: Female Ae. albopictus in WV exhibited the least preference to the BGS traps at all five sites compared to GT and LT. This could be due sampling bias since WV mosquito surveillance strategies have focused on traps used for detection of Culex spp. associated with West Nile virus. The WV mosquito surveillance program will continue to adapt its surveillance strategies in order to better characterize geographic distribution of Ae. albopictus mosquitoes in rural and populated areas and assess the trapping efficiency of BGS through consistent use statewide.