Host preference and resting behavior of Anopheles coluzzii (Diptera: Culicidae) on the island of São Tomé, West Africa

Host preference and resting behavior of Anopheles coluzzii Coetzee & Wilkerson, 2013 were investigated on São Tomé and Príncipe Islands following implementation of an intensive malaria vector control program. Blood meals from indoor- and outdoor-resting females collected in 2021-2024 were identified using established PCR assays targeting mammalian- and avian-specific polymorphisms in the mitochondrial cytochrome b gene. In São Tomé, a total of 2,211 resting mosquitoes were collected, 90% of which were sampled outdoors. An overall human blood index (HBI) of 4% was obtained from 1,227 females analyzed. Most nonhuman blood meals were from pigs (40%) and dogs (50%). Príncipe Island exhibited an HBI of 79%, but only 17 female mosquitoes were sampled, 77% of which indoors. These findings highlight behavioral adaptations in An. coluzzii populations, toward zoophily and exophily, that may reduce the effectiveness of indoor-based vector control measures and therefore underscore the importance of novel strategies targeting outdoor-resting mosquitoes.