Infections with Penicillium spp are rare in domestic animals. In dogs, infections of the nasal cavity, lungs, lymph nodes, and bones have been reported. Nasal disease is most common and behaves similar to nasal aspergillosis. In cats, the fungus has been isolated from the nasal cavity, orbital cellulitis and sinusitis, and lungs. It has also been reported to cause systemic disease in captive toucanets (P griseofulvum) and bamboo rats (P marneffei) in southeast Asia. Penicillium spp are widely distributed in nature and are found in soils, grains, and various foods and feeds.
Dogs with nasal penicilliosis have chronic sneezing and an acute to chronic nasal discharge that varies from intermittent hemorrhagic to intermittent or continuous mucoid or mucopurulent. Radiographic findings include areas of turbinate destruction with increased radiolucency. Grossly, the nasal mucosa has foci of necrosis and ulceration; microscopically, fungal hyphae may form a thick mat over an intact mucosa adjacent to these foci. Systemic disease often affects long bones, resulting in lameness.
Diagnosis is based on fungal culture, character of the lesions, presence of fungal hyphae, and a positive agar-gel double-diffusion test. Cultural isolation of a Penicillium sp must be accompanied by demonstration of tissue invasion by the fungus for confirmation. In tissues, P marneffei closely resemble the yeast phase of Histoplasma capsulatum.
Very little has been reported concerning treatment of penicilliosis. Surgical turbinectomy with curettage has been combined with flushing of the nasal cavity with 1% tincture of iodine or povidone-iodine (10:1) and oral thiabendazole. Fluconazole, 2.5–5 mg/kg/day for 2 mo, has been used to successfully treat some dogs with nasal penicilliosis.