Pneumocystis canis pneumonia in dogs

Pneumocystis canis is a potential cause of life-threatening interstitial fungal pneumonia in dogs. It is seen almost exclusively in two canine breeds, miniature Dachshunds and Cavalier King Charles Spaniels (CKCS). Historically, Australian veterinarianshadakey role in thedocumentation of this entity and its conspicuous breed associations. Affected Dachshunds and CKCS are likely to have an inherited immunodeficiency that predisposes them to infection with this commensal organism of the respiratory tract and pharynx. A high index of suspicion is required tomake a timely diagnosis and save affected patients, as these dogs copepoorlywith anaesthesia andothermeasures to procure the specimens required to make a definitive diagnosis. Possible co-infection with Bordetella bronchiseptica must be considered when determining antimicrobial strategies. Affected dogs occasionally have a previous or concurrent history of generalised demodicosis. With early intervention, affected dogs can be saved, although some require lifelong therapy to prevent recurrence. The future challenge is to develop fast molecular techniques to diagnose P. canis pneumonia (PCP) and to determine the underlying immune defect in over-represented breeds through the rapidly advancing field of canine genomics.