Defining New Pathways to Manage the Ongoing Emergence of Bat Rabies in Latin America.

Rabies transmitted by common vampire bats (Desmodus rotundus) has been known since the early 1900s but continues to expand geographically and in the range of species and environments affected. In this review, we present current knowledge of the epidemiology and management of rabies in D. rotundus and argue that it can be reasonably considered an emerging public health threat. We identify knowledge gaps related to the landscape determinants of the bat reservoir, reduction in bites on humans and livestock, and social barriers to prevention. We discuss how new technologies including autonomously-spreading vaccines and reproductive suppressants targeting bats might manage both rabies and undesirable growth of D. rotundus populations. Finally, we highlight widespread under-reporting of human and animal mortality and the scarcity of studies that quantify the efficacy of control measures such as bat culling. Collaborations between researchers and managers will be crucial to implement the next generation of rabies management in Latin America.

Geographical Analysis for Detecting High-Risk Areas for Bovine/Human Rabies Transmitted by the Common Hematophagous Bat in the Amazon Region, Brazil.

BACKGROUND: The common hematophagous bat, Desmodus rotundus, is one of the main wild reservoirs of rabies virus in several regions in Latin America. New production practices and changed land use have provided environmental features that have been very favorable for D. rotundus bat populations, making this species the main transmitter of rabies in the cycle that involves humans and herbivores. In the Amazon region, these features include a mosaic of environmental, social, and economic components, which together creates areas with different levels of risk for human and bovine infections, as presented in this work in the eastern Brazilian Amazon. METHODOLOGY: We geo-referenced a total of 175 cases of rabies, of which 88% occurred in bovines and 12% in humans, respectively, and related these cases to a number of different geographical and biological variables. The spatial distribution was analyzed using the Kernel function, while the association with independent variables was assessed using a multi-criterion Analytical Hierarchy Process (AHP) technique. FINDINGS: The spatiotemporal analysis of the occurrence of rabies in bovines and humans found reduction in the number of cases in the eastern state of Pará, where no more cases were recorded in humans, whereas high infection rates were recorded in bovines in the northeastern part of the state, and low rates in the southeast. The areas of highest risk for bovine rabies are found in the proximity of rivers and highways. In the case of human rabies, the highest concentration of high-risk areas was found where the highway network coincides with high densities of rural and indigenous populations. CONCLUSION: The high-risk areas for human and bovine rabies are patchily distributed, and related to extensive deforested areas, large herds of cattle, and the presence of highways. These findings provide an important database for the generation of epidemiological models that could support the development of effective prevention measures and controls.

Serological investigation of rabies virus neutralizing antibodies in bats captured in the eastern Brazilian Amazon.

BACKGROUND: In 2004 and 2005 a total of 38 cases of human rabies transmitted by the hematophagous bat Desmodus rotundus were registered in the Brazilian state of Pará; 23 (60.5%) cases occurred in the northeastern region. Because of this, a serological investigation for the antibodies of rabies virus was performed in municipalities of the northeastern state of Pará, in order to assess whether the virus was circulating among different bat species. METHODS: Bats were collected in 2009 with mist-nets during the rainy and dry seasons and blood samples were collected for the serological survey. RESULTS: A total of 307 serum samples were obtained representing 28 bat species. The number of seropositives was high (50.8%, 156/307) and was significantly higher during the rainy season (67.4%, 95/141). No significant difference in rates was found between male and female or adult and juvenile. Seropositive individuals were recorded in 24 species sampled, the most prominent being Artibeus planirostris, with 52.2% (24/46) positive individuals. CONCLUSION: The serological proportion reported in this paper in a large numbers of individuals indicates that the rabies virus circulates quite actively in the study region, but, because of the production of antibodies, the expression of the disease in these individuals is low.