Outbreak of cutaneous pythiosis in cattle

Seventy-six young mixed breed cattle of both sexes, presented multifocal ulcerated nodular cutaneous lesions localized in the medial and lateral aspects of fore and hindlimbs, ventral neck, sternum, and tail. The disease occurred during summer and lesions were observed on areas of the body which were in contact with water of irrigation channels for long periods. Histologically, there were multiple granulomas and pyogranulomas with few negative profiles of hyphae, which were better visualized throughout Grocott methenamine silver stain. Definitive etiologic diagnosis was based on immunohistochemistry with anti-Pythium insidiosum polyclonal antibody. Additionally, an indirect ELISA test was performed. Bovine cutaneous pythiosis outbreaks are uncommon and, particularly as occurred in the cattle of this report, all affected animals had spontaneous healing within two to three weeks.