|A 9-month female intact miniature Kunekune pig presented for an approximately 2-week history of increased respiratory effort, coughing, and hyporhexia, for which she had been treated with Penicillin (1-week duration). Prior to onset of clinical signs, the owner had a cold; the household is additionally comprised of dogs, guinea pigs, and reptiles. The patient had been owned for 6 months, at the beginning of which she was “sick.” No specific diagnosis had been made at that time. The patient was reported to be vaccinated. On presentation, the patient was dull and depressed with increased bronchovesicular sounds, tachypnea, and no nasal discharge.|
Diffusely, the lungs have severely increased soft tissue opacity, which causes faint air bronchograms and incomplete border effacement of the cardiac silhouette and diaphragm. The cardiac silhouette is normal in size; the pulmonary vascular margins cannot be defined. No thoracic lymphadenopathy
• Diffuse unstructured interstitial coalescing to alveolar pattern is most consistent with interstitial pneumonia/pneumonitis (e.g. inhaled toxin, smoke, viral pneumonia).
• Due to chronicity, non-cardiogenic edema (e.g. seizure, electrocution, upper airway obstruction) and hemorrhage were considered unlikely.
Due to concerns for interstitial pneumonia, nasal-swab porcine respiratory panel (porcine reproductive and respiratory syndrome virus multiplex, porcine circovirus type 2, Mycoplasma spp) was performed (all negative). The patient was euthanized after 48 hours of hospitalization and empiric treatment, without improvement. Necropsy yielded morphologic diagnosis of severe, diffuse, interstitial pneumonia and regional lymphoid hyperplasia. Repeat porcine respiratory panel was performed from lung tissue (all negative). Samples of lung tissue were stained with hematoxylin and eosin, as well as with periodic acid-Schiff stain: alveoli were filled with innumerable fungal organisms (see histology images).
The final histology diagnosis was interstitial lymphoplasmacytic and histiocytic pneumonia with myriad fungal organisms (presumptively Pneumocystis jirovecii, formerly Pneumocystis carinii) and granulomatous lymphadenitis with fungal organisms. Although Pneumocystis is most commonly diagnosed in immunocompromised animals, no underlying cause was determined.