Changing dynamics ofAedes aegyptiinvasion and vector-borne disease risk for rural communities in the Peruvian Amazon

Abstract

AbstractAedes aegypti,the primary vector of dengue virus, is predominantly considered an urban mosquito, especially in the Americas, where its reemergence began in cities after the end of continent-wide eradication campaigns. The results of our study diverge from this narrative, demonstrating the recent and widespread rural invasion ofAe. aegyptialong major shipping routes in the northern Peruvian Amazon between the major cities of Iquitos, Pucallpa, and Yurimaguas. We identifiedAe. aegyptipopulations in 29 of 30 sites surveyed across a rural to urban gradient and characterized mosquito larval habitats andAe. aegyptiadult metrics. Households, regardless of community size, were more likely to be positive forAe. aegyptiadult(s) and had a higher number ofAe. aegyptiadults if a mosquito larval habitat was identified on the property, compared to houses without a larval habitat. In multiple instances, adultAe. aegyptiindices in rural villages were equal to or greater than indices in dengue-endemic cities, suggesting the entomological risk level in some rural areas is sufficient to sustain dengue transmission. Fourteen rural sites were sampled in transects from the community river port into town. In seven of these sites, houses closer to the port were significantly more likely to be infested withAe. aegyptiadults than houses further from the ports, and four additional sites had a marginal relationship to the same effect. This pattern suggests that many rural sites are invaded via adultAe. aegyptidisembarking from boats at the port, finding nearby oviposition sites, and advancing stepwise into town. The existence of the pattern also suggests that many of the sites are still experiencing active invasion, with sections of towns stillAe. aegypti-free. Only one site shows a strong signal of invasion via the egg or larval stage, with a focus ofAe. aegyptifar removed from the port. The widespread infestation ofAe. aegyptiin rural areas is a major public health threat given the far distance of communities to hospital care. It is important to implement control measures now before the mosquito gains a stronger foothold in zones of active invasion.