Infecção pelo vírus da cinomose canina em um cachorro-do-mato (CERDOCYON THOUS, LINNAEUS, 1766) de vida livre em uma área periurbana no estado do Ceará, Brasil

Abstract

Canine distemper is a highly contagious, multisystemic viral disease caused by a Morbillivirus that primarily affects domestic dogs; however, a wide range of wild animals are also susceptible to infection, representing a significant threat to wildlife conservation. The objective of this study was to report a case of infection by canine distemper virus in a free-ranging crab-eating fox (Cerdocyon thous) in the Cariri region, Ceará State, Brazil. A young fox was found in a peri-urban area showing neurological signs and was taken to a non-governmental organization for care. During clinical evaluation, the animal initially presented apathy, hypoglycemia, hypothermia, ataxia with circling, involuntary jaw movements, and myoclonus, progressing within three days to severe weakness, prolonged recumbency, vocalizations, and seizures. A rapid test for canine distemper was performed, yielding a positive result. Due to the rapid clinical deterioration, euthanasia was performed. At necropsy, the animal showed a fair body condition, with pale ocular and oral mucous membranes. Tissue fragments were collected and fixed in 10% buffered formalin for histopathological examination. Microscopically, multifocal areas of demyelination were observed in the central nervous system, along with intracytoplasmic and/or intranuclear inclusion bodies in neurons, astrocytes, ependymal cells, and epithelial cells of the tongue and gastric mucosa. Paraffin blocks of the nervous system, tongue, stomach, and spleen were selected for immunohistochemistry using antibodies against canine distemper. Strongly positive immunolabeling occurred in epithelial cells of the tongue and gastric mucosa, in lymphoid cells in the spleen, and in neurons in the cerebellum. The diagnosis of canine distemper virus infection in the fox was established based on clinical, anatomopathological, and immunohistochemical findings. These results highlight the importance of canine distemper as an emerging disease in wild canids and emphasize the need for epidemiological surveillance and disease control in domestic animal populations as an indirect measure for wildlife conservation.