Orchitis in a cat associated with coronavirus infection

Area of Science:

• Veterinary Pathology
• Feline Infectious Diseases

Background:

• Feline infectious peritonitis (FIP) is a systemic disease caused by a coronavirus.
• Clinical signs of FIP typically involve multiple organ systems, but focal presentations can occur.
• Orchitis, inflammation of the testicles, is not a commonly recognized lesion associated with FIP.

Purpose of the Study:

• To describe a case of severe orchitis in a cat.
• To investigate the potential association between orchitis and feline infectious peritonitis (FIP).
• To determine if orchitis should be considered a possible manifestation of FIP.

Main Methods:

• A case study of a single feline patient.
• Clinical examination, castration, and post-mortem examination.
• Histopathological evaluation of affected tissues.
• Reverse transcriptase-polymerase chain reaction (RT-PCR) for coronavirus detection.
• Immunohistochemistry for coronavirus antigen detection.

Main Results:

• A 3.5-year-old cat presented with left testicular enlargement and was positive for feline immunodeficiency virus.
• Post-mortem examination revealed lesions consistent with FIP in abdominal organs and the brain.
• Coronavirus antigen and RNA were detected in the affected testicle and other tissues, confirming FIP.
• Severe pyogranulomatous and necrotizing orchitis was diagnosed in the affected testicle.

Conclusions:

• This case demonstrates that orchitis can be a rare lesion associated with feline infectious peritonitis (FIP).
• Clinicians should consider FIP in the differential diagnosis for cats presenting with orchitis, even if other signs are not immediately apparent.
• Further research may be warranted to understand the frequency and pathogenesis of FIP-associated orchitis.