Thoracic and abdominal blastomycosis in a horse.

The research article describes the diagnosis, treatment and post-mortem findings of a five-year-old horse suffering from thoracic and abdominal blastomycosis, a rare and serious fungal infection.

Clinical Examination and Findings

Upon examination, the horse showed symptoms of lethargy, high body temperature and weight loss over the past month. The veterinarians conducted a thoracic auscultation and ultrasonography, which picked up reduced lung sounds and anechoic areas with fibrin tags, respectively – indications of a pleural effusion (extra fluid around the lungs). An advanced stage of disease could also be detected from the presence of free fluid during an abdominal ultrasonography.

Blood Analyses

Additional tests were conducted to confirm the diagnoses:

• Anemia (a low number of red blood cells), hyperproteinemia (elevated levels of proteins in the blood), hyperglobulinemia (excess globulins in blood), hyperfibrinogenemia (elevated levels of fibrinogen), and hypoalbuminemia (low levels of albumin in blood) were all observed in blood tests. These abnormalities suggested an underlying infection.

Radiography and Aspirate Examination

When a thoracic radiography was performed, it showed alveolar infiltrates (collections of fluid and cells) in the lung fields. This was alongside the visualization of a cavitary mass resembling an abscess near the diaphragm. An ultrasonographic evaluation of this area further confirmed the existence of a septated hypoechoic mass.

• Bilateral thoracocentesis was then conducted, which involved the insertion of a needle into the pleural space of the chest to drain the fluid and perform further testing.
• Bacterial culture of the drained pleural fluid did not indicate the presence of bacterial growth but fungal organisms, specifically Blastomyces dermatitidis. This fungus was also abundantly present in the horse’s abdominal fluid and an aspirate of the abscess.

Diagnosis, Treatment and Post-Mortem Examination

These extensive clinical, blood and additional investigation findings led to the definitive diagnosis of thoracic and abdominal blastomycosis. Unfortunately, due to the severity of the disease, the decision was taken to euthanize the mare. A necropsy (animal autopsy) was performed after death, which confirmed the diagnosis of thoracic and abdominal blastomycosis.