Rabies Virus Exposure of Brazilian Free-ranging Wildlife from Municipalities without Clinical Cases in Humans or in Terrestrial Wildlife

Abstract

Rabies is a zoonosis that causes thousands of animal and human deaths worldwide. Serological studies provide information concerning rabies virus circulation among animals and humans. We evaluated the circulation of the rabies virus in wildlife in nine municipalities of São Paulo State, Brazil. We took blood samples from 27 terrestrial animals of nine different mammalian species in locations without cases of rabies in human and wild terrestrial mammals. Sera were tested with the use of the rapid fluorescent focus inhibition test (RFFIT) for the detection of rabies virus-neutralizing antibodies (RVNA). The RFFIT was positive in 100% of the samples, with many (81.48%) showing protective titer levels (>0.5 IU/mL) with other samples (18.52%) showing titers representing exposure (<0.5 IU/mL). We report RVNA in novel species (e.g., Alouatta caraya and Tapyrus terrestris). Wild animals were exposed to rabies virus in municipalities without a history of human rabies cases, which demonstrated a need for research to understand the role of these animals in the circulation and transmission of the disease.

Using Surveillance of Animal Bite Patients to Decipher Potential Risks of Rabies Exposure From Domestic Animals and Wildlife in Brazil

“…Marmosets are also host to a distinct RABV variant in the Northeast region of Brazil (9,11). In the states of São Paulo and Rio Grande do Sul (RGS) in Southern Brazil, RABV circulation has been detected in vampire bats, insectivorous bats, capuchin monkeys, and crab-eating foxes (12)(13)(14)(19)(20)(21). These reports suggest the circulation of rabies among different wildlife populations in several regions of the country, posing risks to humans and domestic animals that will depend upon contacts between these populations.…”

“…In particular, most human deaths and livestock losses from rabies in the continent are now attributed to spillover from vampire bats, Desmodus rotundus ( 6 – 8 ). Foxes (specifically the crab-eating fox Cerdocyon thous ) and primates (specifically the marmoset Callithrix jacchus ) are also considered reservoirs of specific RABV variants ( 9 – 12 ), while serological studies show evidence of rabies exposure in several other primate and marsupial species but without evidence of clinical infections ( 13 , 14 ).…”

Abortive vampire bat rabies infections in Peruvian peridomestic livestock

“…However, the detection of RVNAs in a variety of non-bat species has raised the possibility that abortive infections could be widespread in both reservoir and non-reservoir hosts [11,12]. RVNAs have been reported in apparently healthy and unvaccinated non-human primates, opossums and wild canids [10,[13][14][15][16] and following experimental infections of laboratory animals [17]. Abortive infections also occur in humans with routine contacts with rabies reservoirs [18][19][20][21] and in cattle bitten by vampire bats [22].…”

Predicting the presence and titre of rabies virus‐neutralizing antibodies from low‐volume serum samples in low‐containment facilities

“…Titres ≤ 0.1 IU/ml were considered RVNA‐negative and > 0.1 IU/ml were considered RVNA‐positive. Other serology studies in wildlife have used similar thresholds to detect RVNA (Araujo et al., 2014; Campos et al., 2019; Marcelo Azevedo de Paula Antunes et al, 2017; Silva et al., 2010). To predict RVNA titres, a GLMM with a log‐normal distribution was fit to the infected cell counts across the SRIG concentration series.…”