Building resilience against the growing threat of arboviruses II: a scoping review of Aedes vector competence, larval and adult bionomics and species distribution in Africa.

backgroundReports of arboviral outbreaks are increasing, yet there are acknowledged shortfalls in surveillance data and outbreak preparedness on the African continent. The second part of this scoping review features Aedes vector-pathogen interactions, bionomics and species distribution.

methodsWe reviewed studies published between 1980 and 2023 to synthesize existing information and identify knowledge gaps to guide future Aedes research and control in Africa.

results877 full-text articles were reviewed, 70 featured vector-pathogen interactions, 230 vector bionomics and 394 species distribution. Vector competence studies were limited to a handful of countries, highlighting knowledge gaps regarding urban, bridge and sylvatic vector species competence for major arboviruses. Aedes albopictus was highly competent for chikungunya virus with the E1-226V mutation, which has been implicated in epidemics where Ae. aegypti was displaced. Vector competence was dependent on virus lineage and mosquito population. Ae. aegypti competence to dengue virus was highly variable, whereas Ae. albopictus was an efficient vector of Zika virus for African but not Asian lineages. Discarded tires were the most frequently reported positive breeding habitats, ranking among the top three in 55% of publications, followed by other discarded items (cans, bottles, broken plastic items) and water storage containers; however, the relative importance varied by location. The pupal index was reported less frequently than traditional indices (container, Breteau and house indices), which co-occurred in 84% of studies reporting indices. As pupal counts are a better proxy for adult mosquito production, their wider use is recommended to identify locally important breeding sites for targeted control. Adult vector monitoring has shifted away from human landing catch towards BG-Sentinel and CDC-LT traps which may be less accurate proxies of human-vector contact, but efficiency can be improved using attractants. Ae. aegypti was highly anthropophilic and had a major biting peak before sunset. However, findings of Ae. aegypti biting at night-time and being zoophilic in some locations demonstrate the need for periodic monitoring, given changing environmental conditions.

conclusionsThis review highlights how Aedes populations vary in their competence for key arboviruses, their breeding habitats, and biting behaviors across Africa. Understanding these patterns can guide targeted vector control and improve preparedness for arbovirus outbreaks.