Equine salmonellosis in southern Brazil

The Salmonella sp. genus is identified in several species, and the zoonosis it causes is one of the most important types worldwide. The specifics of salmonellosis vary according to the function of the serovar involved, the species affected, age and predisposing factors. However, few cases of equine salmonellosis have been reported. This study presents ten confirmed salmonellosis cases in equines in southern Brazil. Six were adult animals with stress factors preceding the disease, while four were foals, three of which presented with hyperacute manifestations. The main clinical signs were diarrhea, anorexia, and hyperthermia. Lesions varied in distribution and severity, although fibrinonecrotic or necrohemorrhagic enteritis was observed in all animals, mainly in the large intestine (large colon and cecum-8/10) and small intestine (3/10). Substantial liquid content, mainly hemorrhagic, was observed in all animals. The most characteristic microscopic lesion was mucosa necrosis, which is often accompanied by fibrin deposition, followed by necrosis of follicular centers and vascular changes. Bacterial isolation revealed seven isolates. Five were serotyped, and the serovars Typhimurium and Anatum were associated with two cases each, while Muenster was associated with a case whose lesion pattern varied. Immunohistochemical staining was positive in all cases. All diagnoses were based on the clinical history, macroscopic and histological lesions, and the bacterial isolation and/or immunostaining associated with histological lesions.