Multi-pathogen lower respiratory tract infection including a fungal agent in a yearling mustang filly

This report describes the diagnosis and successful management of a yearling filly with Coombs-positive anemia, thrombocytopenia, and fungal pneumonia. Diagnostic procedures, including thoracic ultrasonography and radiography, respiratory pathogen PCR testing, and evaluation of tracheal wash and bronchoalveolar lavage samples established multi-pathogen lower respiratory tract infection including a fungal agent. Orally administered voriconazole was a key component of treatment in this case to successfully eliminate fungal infection, alongside therapies for managing hematologic disease. This case demonstrated the importance of comprehensive diagnostic evaluation and reliance on current literature to successfully resolve a complicated medical situation that was expected to have a poor prognosis. Key clinical message: The pharmacokinetics of orally administered voriconazole have been established in horses. This drug can be economic and effective for the treatment of some fungal respiratory infections of horses.