Aspergillosis in cats

Feline sino-orbital aspergillosis is a fungal infection of the nasal region which affects mainly brachycephalic (flat-faced) cats, of which Persians are a breed overrepresented.

Clinical signs

There are a distinct set of clinical signs including exophthalmos (protruding eye), ocular discharge, prolapse of the nictitating membrane and exposure keratitis. The fungi involved (Aspergillus fumigatus, Penicillium spp and Pythium spp) invade the sinus cavities of the cribriform plate, orbit, palate and nasopharynx. Invasion of the palatine bone and nasopharynx can result in visible lesions or ulceration of the soft and hard palates.

Diagnosis

Diagnosis is based on clinical signs and biopsies confirming presence of fungal hyphae and eosinophilic inflammation.

Figure 1. Cat showing left eye enlargement and protrusion of third eyelid	Figure 2. Oral swelling associated with nasopharyngeal tumour
Figure 3. Cytologic appearance of macroconidium (left side of image) covered with slightly refractile fungal spores (respiratory aspergillosis, Wright stain).	Figure 4. Cytologic appearance of fungal hyphae with parallel walls, septa, and branching consistent with Aspergillus sp. (respiratory aspergillosis, Wright stain).

Treatment

Treatment regimens are based on responses seen with other fungal infections, most importantly Cryptococcus. Such drugs include ketoconazole, fluconazole, 5-flucytosine and Amphotericin-B (see Drugs for dose rates).