Acremonium strictum pulmonary infection in a horse.

The research article chronicles the case of a horse diagnosed with a lung infection caused by the fungal species Acremonium strictum. After a period of treatment, the horse successfully recovered from the condition.

Case Presentation and Diagnosis

• The subject of the study was a 10-year-old Thoroughbred gelding that was taken to the Veterinary Medical Teaching Hospital of the University of California-Davis. The horse had been exhibiting signs of intermittent fever, acute onset of lethargy, anorexia, and ataxia (loss of control of bodily movements).
• Preliminary hematologic and biochemical analysis indicated a chronic inflammatory process in the horse, however, the clinical signs were nonspecific.
• Thoracic radiographs of the horse further revealed an increased fine reticulonodular interstitial opacity, particularly throughout the dorsal caudal lung fields. This condition is characterized by an unusal pattern on the radiograph which is often an indication of a lung disease.
• Further evaluation by cytologic examination of bronchoalveolar lavage (BAL) fluid, which is a tool used to diagnose lung diseases, showed mixed inflammation with a significant amount of mononuclear phagocytes. These are a type of immune cells that engulf and digest cellular debris and foreign substances.
• These phagocytes contained single, spherical, intracytoplasmic fungal organisms. Intracytoplasmic means ‘within the cell’ and so, these organisms were identified inside the aforementioned immune cells.

Culture and Testing

• Four different mold species were cultivated in limited numbers from the BAL fluid of which one was identified as Acremonium strictum. This identification was done using real-time polymerase chain reaction (PCR), a technique used to amplify selected sections of DNA or RNA for analysis.
• Given these findings – results from the thoracic imaging, cytologic evaluation, culture, and PCR testing, a diagnosis of fungal pneumonia due to Acremonium strictum was made. Pneumonia is a lung inflammation caused by fungal, bacterial, or viral infection, in which the air sacs fill with pus and may become solid.

Recovery and Follow-up

• Following diagnosis, the horse was treated and made an uneventful recovery.
• The horse was later examined 21 days after presentation and was determined to be disease-free based on normal physical, radiographic, and cytologic findings.
• Researchers then conclude that, to the best of their knowledge, this is the first known case of the isolation of Acremonium strictum from the BAL fluid of a horse diagnosed with interstitial pneumonia.