Serological Surveillance of Rabies in Free-Range and Captive Common Vampire Bats Desmodus rotundus.

Jane Megid,Bruna Letícia Devidé Ribeiro,Luzia Fátima Alves Martorelli,Marilene Fernandes De Almeida,Iana Suly Santos Katz,Gisely Toledo Barone,Fernando Favian Castro Castro,Julio Andre Benavides Tala,Adriana Ruckert Rosa,Camila Michele Appolinário,Sandriana Ramos Silva,Laís Dário Belaz Silva,Karin Corrêa Scheffer

doi:10.3389/fvets.2021.681423

Abstract

The control of vampire bat rabies (VBR) in Brazil is based on the culling of Desmodus rotundus and the surveillance of outbreaks caused by D. rotundus in cattle and humans in addition to vaccination of susceptible livestock. The detection of anti-rabies antibodies in vampire bats indicates exposure to the rabies virus, and several studies have reported an increase of these antibodies following experimental infection. However, the dynamics of anti-rabies antibodies in natural populations of D. rotundus remains poorly understood. In this study, we took advantage of recent outbreaks of VBR among livestock in the Sao Paulo region of Brazil to test whether seroprevalence in D. rotundus reflects the incidence of rabies in nearby livestock populations. Sixty-four D. rotundus were captured during and after outbreaks from roost located in municipalities belonging to three regions with different incidences of rabies in herbivores. Sixteen seropositive bats were then kept in captivity for up to 120 days, and their antibodies and virus levels were quantified at different time points using the rapid fluorescent focus inhibition test (RFFIT). Antibody titers were associated with the occurrence of ongoing outbreak, with a higher proportion of bats showing titer >0.5 IU/ml in the region with a recent outbreak. However, low titers were still detected in bats from regions reporting the last outbreak of rabies at least 3 years prior to sampling. This study suggests that serological surveillance of rabies in vampire bats can be used as a tool to evaluate risk of outbreaks in at risk populations of cattle and human.

Highlights

Rabies is an infectious disease of viral etiology that causes acute encephalitis, with rapid and usually fatal evolution in all mammals [1]
The highest rabies antibodies titers were obtained from bats captured in Botucatu (0.45 ± 0.05), which had the most recent outbreaks
We found that vampire bats from the region of Botucatu, which had experienced a recent outbreak of rabies in cattle 30 days prior to sampling, showed a high proportion of seropositive individuals compared to two other sampling sites where the latest outbreak in cattle was reported at least 3 years prior to sampling

Summary

Introduction

Rabies is an infectious disease of viral etiology that causes acute encephalitis, with rapid and usually fatal evolution in all mammals [1]. The etiological agent is the RNA virus belonging to the family Rhabdoviridae and genus Lyssavirus, and it is a zoonosis distributed worldwide that affects mainly low-income countries [2]. Dogs are the main reservoir of rabies and are responsible for most fatal cases in humans worldwide [2]. In Latin America, with success obtained by the countries to control rabies mediated by dogs through the mass vaccination campaign [3, 4], bats have become the main reservoir of rabies over the last decade and are responsible for thousands of cases in livestock and for most of the remaining cases in humans [1, 4]. The common vampire bat Desmodus rotundus is the most important reservoir because of the high occurrence of spillover of rabies from this species of bat to other animals and humans, and vampire bat rabies (VBR) remains unpredictable and uncontrolled in several areas of the continent

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Conclusion