Rhinitis in goat by Exserohilum rostratum (Setosphaeria rostrata)

Abstract

ABSTRACT: We described a case of rhinitis case caused by Exserohilum rostratum in a 3-year-old, mixed breed, afemale goat, presenting with decreased appetite, dyspnea, and face deformity, with evolution of approximately 2 months. Necropsy revealed an extensive brownish yellow, irregular, ulcerated, and friable focal lesion in the nasal cavity. Purulent secretion drained from the lesion, affecting the nasal vestibule and extending the caudal portion of the dorsal concha, associated with nasal meatus obstruction, destruction of the nasal septum, and nasal bone palatine and vomer. Histologically, the lesion was characterized as rhinitis and pyogranulomatous and necrotizing osteomyelitis (multifocal to coalescent, sharp, and chronic) and associated with a myriad of fungal structures. Morphologically, the hyphae were characterized by thin, slightly tortuous, and rarely septate walls (2-6 μm diameter), multiple chains of individual conidia or in groups (8-10 μm diameter), and pigmented chlamydoconidia (7.5-15 μm diameter). They showed positive results for the special histochemical techniques such as Fontana Masson, methenamine silver nitrate by Grocott, and periodic acid by Schiff. E. rostratum was identified as the causative agent using microbiological isolation associated with molecular identification. Pyrogranulomatous rhinitis caused by E. rostratum in goats is unprecedented, being the first isolation of the agent in animals in Brazil and the first case of nasal phaeohyphomycosis in the goats.