Viral highways in the night sky
In the cattle-ranching regions of Northwest Argentina, the common vampire bat, Desmodus rotundus, is the primary reservoir for the rabies virus. This nocturnal mammal, which feeds exclusively on blood, has expanded its population alongside the growth of the livestock industry, its main food source. Rabies transmitted by these bats is a significant economic and public health issue, causing fatal paralytic illness in cattle and occasionally spilling over into other wild animals and humans. The northern part of Argentina is considered an endemic area for rabies transmitted by these bats.
Scientists studying the virus's transmission dynamics have found a complex pattern of spread. Phylogenetic analysis, which examines the genetic makeup of the rabies virus (RABV), has shown that different viral variants exist in distinct geographical areas. Two major groups of RABV variants have been identified in Argentina: one in the northwest and another in the northeast. These regions have different climates and topography, which influence the virus's evolution and spread. The transmission of rabies by vampire bats is characterized by epizootic waves—large outbreaks that spread through a population—followed by periods where the disease circulates at low levels locally.