Secondary transmission of rabies in Latin America

Abstract

Compared to primary pathways among reservoirs, secondary transmission of rabies virus has not received much attention from researchers or public health professionals, because spillover of infection from hematophagous and non-hematophagous bats to a potential vector is believed to be uncommon. This review seeks to remind those working on Latin American rabies control programs of the possibility of a bat-cathuman pathway. Following the increase in the control of canine rabies in most Latin American countries, epidemiological surveillance also focused on hematophagous and non-hematophagous bats and the use of molecular techniques in the characterization of rabies. At least eight cases of secondary transmission to humans were identified in Latin America from 2001 to 2012: one in Brazil (2001), two in Costa Rica (2001), four in Colombia (two in 2008 and two in 2012) and one in Ecuador (2009). In each case, the epidemiological investigation implicated a cat as the vector. The antigenic and genetic analyses identified variants maintained by the hematophagous bat Desmodus rotundus. Fruit-eating bats in the genus Artibeus may also be affected by a variant similar to that of D. rotundus. Such fruit bats may be found in urban areas. Such affected species can transmit rabies virus to felids, which are important predators of bats. Therefore, in cases of human rabies following aggression by cats in areas that are otherwise free of canine rabies (variants 1 and 2) but where there are rabies epizootics in sentinels such as herbivores, the hypothesis of secondary transmission of bat rabies viruses should always be investigated.