Current Knowledge and Ecological and Human Impact Variables Involved in the Distribution of the Dengue Virus by Bats in the Americas

Dengue fever, caused by the dengue virus (DENV), is one of the most important reemerging viral diseases transmitted by arthropods worldwide. DENV is maintained in nature in two transmission cycles: urban and sylvatic. The latter has only been recorded in Africa and Asia and involves nonhuman primates as natural hosts, although it has been suggested that other mammals may play a secondary role as potential reservoir host, including bats. The objective of this article is to review the current state of knowledge about DENV-positive bats in the Americas and to determine what ecological and human impact variables could favor DENV infection in bats. We performed a search of published studies on natural and experimental DENV infection in bats. From 1952 to 2019, 14 studies have been carried out (71.4% in the last decade) examining DENV infection in bats in seven countries of the Americas. DENV infection was examined in 1884 bats of 63 species and DENV was detected in 19 of these species. Clench's model estimated that more than 75 species could be carriers of DENV; therefore, considering that at least 350 species of bats are distributed in the Americas, to detect 95% of the DENV-bearing species, it would be necessary to examine about 10,206 bats of ∼287 species that have not been analyzed until 2019. The species with the highest number of positive cases were Molossus sinaloae and Artibeus jamaicensis. Species, colony size, mean annual temperature, mean annual precipitation, human population size, and bat collection site (site inhabited by humans, vegetation cover, and caves) contributed to explain the variation in DENV detection in bats in the Americas. These results provide evidence on the exposure of bats to DENV in different geographic areas of the Americas and a bat sylvatic transmission cycle is very likely to be occurring, where bats may be either accidental hosts, dead-end hosts, or potential reservoir hosts for DENV.