DNA barcoding and blood meal profiling of Ethiopian mosquitoes (Diptera: Culicidae): insights into species identification and host preferences

Arboviruses continue to threaten global health because of their rapid geographical expansion and significant disease burden. Of the over 500 recognized arboviruses, approximately 150 affect humans, and around 50 affect domestic animals and wildlife. The spread and impact of these viruses have increased significantly over the past three decades, driven by the proliferation of their vectors and the rise of global trade and travel.

In this study, we used molecular methods to characterize mosquito species diversity and host feeding preferences across Ethiopia's Great Rift Valley. Mosquitoes were collected from diverse habitats in the Great Rift Valley of Ethiopia using Centers for Disease Control and Prevention (CDC) light traps, BG-Sentinel traps, and hand aspirators. The area was chosen for its high vector diversity, suitable breeding habitats, and the epidemiological importance of arboviruses. Morphological identification was conducted, and 204 blood-fed mosquitoes were selected. Genomic DNA was extracted, followed by polymerase chain reaction (PCR) amplification targeting the COI gene. Blood meal analysis was performed using vertebrate-specific primers targeting the 12S rRNA gene. Mosquito species identification, genetic diversity analysis, and phylogenetic analyses were conducted.

Of 6601 collected mosquitoes, 4977 were identified morphologically, comprising 399 Aedes, 2861 Culex, 1841 Anopheles, and 275 Mansonia species. COI DNA barcode analysis identified 142 mosquito specimens belonging to 16 species, with Anopheles coustani, Cx. tritaeniorhynchus, Cx. pipiens complex, Mansonia africana, and Ma. uniformis being the predominant species. Blood meal analysis (n = 71 successful amplifications) revealed a primary reliance on humans and cattle. Cx. pipiens complex showed a strong anthropophilic tendency, while Cx. tritaeniorhynchus and Ma. uniformis exhibited broader host ranges. Genetic diversity indices showed significant Fu's F_s statistics for Cx. pipiens complex, Cx. tritaeniorhynchus, Ma. africana, and Ma. uniformis.

This study offers valuable preliminary insights into the diversity of mosquito species, genetic variation, and host-feeding preferences within the Ethiopian Rift Valley. The findings emphasize the potential of molecular techniques to enhance traditional entomological methods and improve the accuracy of mosquito identification. While the study is limited in both geographic and temporal scope, it highlights mosquito species of medical and veterinary significance and suggests implications for arboviral disease surveillance.