Mapping mosquitoes and their associated pathogens in West Africa

Mosquitoes transmit diverse pathogens, some of which cause mosquito-borne diseases (MBDs). Climate and socioeconomic changes, such as temperature fluctuations, altered rainfall patterns, and urbanization, may affect the distributions of key vectors, particularly Aedes and Anopheles, and increase the health burden of MBDs. West Africa is a historically high-endemic region for MBDs, including malaria and dengue. However, existing studies in this region remain limited in scope, making comprehensive, high-resolution spatial mapping of vectors and pathogens inadequate. This study aimed to map the distributions of mosquitoes and mosquito-associated pathogens and identify potentially suitable areas for key mosquito species in West Africa, thereby supporting regional surveillance and control efforts.

We conducted a scoping review of English-language studies in PubMed, Web of Science, Embase, and Scopus through 7 March 2023. From eligible studies, relevant online databases, and GenBank, we extracted records of mosquito species, mosquito-associated pathogens, and human infections documented by outbreaks, pathogen isolation, molecular detection, or serology. Geographic records were standardized to WGS84 and mapped in ArcGIS 10.7. Potential distributions of key mosquito species were modeled in Maxent 3.4.1 using 24 climatic, topographic, population, land-cover, and related variables. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC).

We compiled 19,578 occurrence records for 302 mosquito species in 16 genera and 598 records for 124 mosquito-associated pathogens from 22 families; 20 pathogens were reported to infect humans. Aedes, Anopheles and Culex occurred in all 16 countries, and Anopheles harbored the most pathogen species (n = 55). DENV was detected in mosquitoes in five countries but human infections were reported in 13. Models for nine key mosquito species yielded AUC values of 0.763-0.912. Land cover contributed more than 10% to six models, and suitable habitats were predicted in Cape Verde for five species without occurrence records in the country.

We established a geospatial database of mosquitoes and their associated pathogens in West Africa. Current records remain incomplete and unevenly distributed, with gaps in key vector occurrence and limited mosquito-based detection of viral and parasitic pathogens relative to human infection evidence. Ecological niche modeling suggests that suitable habitats of some important mosquito species may extend beyond their reported ranges. These findings can guide targeted field surveys and coordinated mosquito-pathogen surveillance in under-sampled areas of West Africa.