Abstract
The objective of the case report was to report the clinical case of a mare with acute piroplasmosis, analyzing epidemiological aspects and pathological severity of the disease. An female equine, Quarter Horse, 8 years old, was referred to the Veterinary Hospital “Roque Quagliato” with a main complaint of cough, nasal discharge, apathy, hyperthermia and hemoglobinuria. The patient had already been diagnosed with Babesia spp. On physical examination, it had icteric mucous membranes, hyperthermia and massive sound in percussion of the right paranasal sinus. In the blood exam, anemia was identified and in biochemical exame, increase in the level of ALT and AST enzymes and urea. At endoscopy, congestion of the tracheal mucosa was noted. In hematozoa research, the presence of intra-erythrocytic piroplasmas was confirmed, and urinalysis had color change. After 15 hours of hospital care, the patient died. The study of the prevalence of equine piroplasmosis is important for determining the epidemiological situation and health control of places that have equine breeding. When there is suspicion, it is necessary to contact the responsible veterinarian to start the therapy, since it is a disease that can lead to losses, especially economic losses. It is also must be considered as an important differential diagnosis between the species.

