Invasion of forested areas in Gabon (Central Africa) by the Asian tiger mosquito and the potential consequences from the One Health perspective

Since its first record in urban areas of Central-Africa in 2000s, the invasive mosquito, Aedes albopictus, has continued to spread across the region, including in remote rural areas, and promoted outbreaks of Aedes-borne diseases, such as dengue, chikungunya and Zika. From the One-Health perspective, such invasion might enhance Ae. albopictus interactions with wild animals in forest ecosystems and favor the spillover of zoonotic arboviruses to humans. From 2014 to 2018, we monitored the steady spread of this mosquito species in the wildlife reserve of La Lope National Park (Gabon), and evaluated the magnitude of its colonization of the rainforest ecosystem using ovitraps, larval surveys, BG-Sentinel traps, and human landing catches following an anthropization gradient. We detected Ae. albopictus in forest galleries up to 15km away from La Lope village. However, Ae. albopictus was significantly more abundant at anthropogenic sites than in less anthropized areas. The number of eggs laid by Ae. albopictus decreased progressively with the distance from the forest fringe up to 200m inside the forest, showing that its occurrence in forest ecosystems is restricted to anthropized-sylvatic interfaces with dense forest. This suggests that Ae. albopictus may act as bridge vector of zoonotic pathogens between wild and anthropogenic compartments.