Spatial Distribution of Bat Shelters and Livestock Rabies in Southern Brazil

Abstract

This study focused on the epidemiological characterization and spatial distribution of bat shelters concerning livestock animal rabies in Paraná State, southern Brazil. A spatiotemporal cluster analysis was performed based on rabies-positive cases and the Desmodus rotundus shelters. A total of 1742 suspect rabies cases submitted for diagnosis from 2011 to 2017 were analyzed; 481 (27.61%) were positive, and 1261 (72.39%) were negative by direct immunofluorescence and biological testing in mice. Out of the positive samples, 413/481 (85.8%) was bovine, 44/481 (9.1%) equine, 6/481 (1.2%) sheep, 5/481 (1.0%) bubaline, and 14/481 (2.9%) were bats. From 22 Regional Units of Agricultural Health, the northeast 129 (26.82%) and central 86 (17.88%) units had the highest recurrence rates of positive cases. Paraná State was continuously endemic for livestock rabies, with the highest caseload seen in the southern-central regions, which was associated with the highest number of vampire bat shelters and natural geographical characteristics favoring bat housing. There was a decrease in the number of rabies cases in livestock in 2013 and 2014. Spatiotemporal analyses of point process mapping and control of D. rotundus shelters and suspected livestock rabies cases in the study area were steady and statistically correlated. However, as bats may travel up to 35-40 km to prey on cattle clusters, bat shelter locations may not be the most sensitive measure of exposure. Furthermore, future studies should consider landscape features such as altitude as potential associated risk factors. Rabies vaccination of livestock and bat hematophagous shelters identification combined with bat control is recommended to increase the efficacy of preventive measures, particularly in natural geographic characteristics favoring local bat housing.