Identifying wildlife diseases is important for conservation and for public health. About 60% of diseases affecting humans are zoonotic, and so biodiversity and ecosystem conservation may influence human health. Some wildlife species, such as the crab-eating fox Cerdocyon thous, may be sentinels for potentially zoonotic infectious diseases because of their generalist diet and opportunistic predation strategy, being found in rural and sometimes urban areas. We investigated the presence of viruses in free-living C. thous in the coastal region of the state of Espírito Santo, southeastern Brazil. We analyzed kidney, liver and faecal samples of 29 road-killed foxes. Viscera were negative for viruses. Two faecal samples (7%) were positive: one for Avian Adenovirus E 8b and Equine Cyclovirus 1, and the other for Porcine Circovirus type 2. Viruses that are typically from other animal species being found in faeces of Cerdocyon thous, along with negative results for viruses in viscera, suggests that the foxes were not infected by the viruses. We suggest that they fed on infected material (e.g. faeces or carcasses of other animals) that in effect could be vector for the gastroenteric viruses. Thus it is possible that they may become infected by feeding on infected material. The use of road-killed animals provides access to biological material that might otherwise be unavailable, and thereby allowing studies that would be very difficult or impossible without these specimens. Also, epidemiological surveillance of wild species may be easily carried out with road-killed animals.