Effects of Seasonal Conditions on Abundance of Malaria Vector Anopheles stephensi Mosquitoes, Djibouti, 2018–2021

The StudyIn coordination with the CLDJ Expeditionary Medical Facility, during January 2018-April 2021, we conducted weekly mosquito surveillance at 32 on-base sites covering 2 km 2 and stored information in dataset A. In October 2019, we began identifying monthly captures of An. stephensi mosquitoes specifically (i.e., identified at the species level) (dataset B).We set US Centers for Disease Control and Prevention (CDC) CO 2 -baited Miniature Light traps (https://www.cdc.gov/mosquitoes/guidelines/west-nile/surveillance/environmental-surveillance.html) and Woodstream Mosquito Magnet (MM) propane-generated CO 2 traps (https://www.woodstream.com)overnight near dwellings, dining areas, sport facilities, and other areas frequented by humans.We identified Anopheles species on the basis of criteria published elsewhere (10,11).We analyzed abundance data in the context of specific weather events and seasonal climatic trends at the time of collection.We obtained meteorologic data from several sources (Appendix, https://wwwnc.cdc.gov/EID/article/29/4/22-0549-App1.pdf), using latitude 11.54733 N and longitude 43.15948 E (0.6-1.2 km from study sites) for location and a locally appropriate meteorologic calendar to determine seasons.We assessed the effects on An. stephensi mosquito abundance of monthly mean temperatures and rainfall amounts at time of precipitation and at 2-week, and 1-and 2-month lag times (i.e., time after rainfall).We did not consider longer lag times because of the likely effects of evaporation. Effects of Seasonal Conditions on Abundance of Malaria Vector Anopheles stephensi Mosquitoes, Djibouti, 2018-2021