Microsporidial Granulomatous Conjunctivitis in a Bearded Dragon ( Pogona vitticeps ): A Case Report

Abstract

An eight-month-old female bearded dragon ( Pogona vitticeps ) was presented with chronic nodular conjunctivitis of the left lower eyelid that failed to respond to previous topical antibiotic and anti-inflammatory therapy. Histopathological examination of an excisional biopsy revealed marked granulomatous inflammation in the lamina propria and submucosa. Special stains (Gram, PAS) demonstrated numerous microsporidia within sporophorous vacuoles, while Ziehl–Neelsen staining for acid-fast bacteria was negative. Based on the histopathological findings and results of special stains, a diagnosis of microsporidial granulomatous conjunctivitis was established. Postoperatively, the patient was treated with tobramycin–dexamethasone eye drops in a tapering regimen for four weeks, resulting in local resolution of the lesion. However, the animal died two months after the initial ophthalmological examination. As post-mortem examination was not performed, systemic microsporidial infection, previously reported in bearded dragons, cannot be excluded. This case highlights microsporidia as a potential cause of chronic conjunctival lesions in bearded dragons and emphasizes histopathology with special stains as a key diagnostic tool.