Effects of Seasonal Conditions on Abundance of Malaria Vector <i>Anopheles stephensi</i> Mosquitoes, Djibouti, 2018–2021
Alia Zayed, M. S. el din M. Moustafa, Reham A Tageldin, James F. Harwood
Abstract
A nopheles stephensi mosquitoes, an urban malaria vector, have established robust populations in the Horn of Africa. Since the mosquito's detection in 2012 (1), malaria cases in Djibouti increased 42.9-fold during 2013-2021, reaching 72,300 cases (2). Before introduction of An. stephensi mosquitoes, Djibouti was approaching the preelimination phase for malaria (3). Because An. stephensi mosquitoes are competent vectors for Plasmodium falciparum and P. vivax parasites (3), WHO considers this mosquito species a major threat to malaria elimination in Africa (4). An. stephensi mosquitoes have also been detected in Sudan, Ethiopia,. Understanding An. stephensi mosquito adaptation to environmental conditions affecting population dynamics in urban settings is crucial in Africa. An. stephensi mosquitoes abundance (number of mosquitoes collected per trap night) changed from seasonal during fall-spring 2013-2016 to year-round in 2017 (3). Since An. stephensi mosquitoes were introduced, malaria cases have increased among military personnel, some immunologically naive, deployed as members of multinational militaries in Djibouti (9). Camp Lemonnier (CLDJ), a US naval base, has urban characteristics similar to the city of Djibouti, in which it is located. For this study, we monitored vector dynamics on the base, providing data to help inform health protection strategies among both military and civilian populations.