Equine rhinosporidiosis.

The study discusses a case of equine rhinosporidiosis found in an Argentinian polo pony mare. The findings confirm the possibility of rhinosporidiosis potentially emerging as a common disease in equines.

Case Identification and Procedure

• An Argentinian polo pony mare was found to have a granulomatous lesion of 18mm on its nasal septum. This was discovered during a pre-purchase check-up.
• The lesion was surgically removed and preserved in 10% formalin for histopathological analysis. This removal procedure was complemented with two freeze/thaw cryosurgery cycles on the base of the growth and surrounding mucosa.
• The healing process was unusually rapid. It took three weeks for the area to be wholly covered by grossly normal-appearing mucosa.

Microscopic Analyses and Findings

• A microscopic analysis of the lesion showed a significant inflammatory infiltrate in the submucosa. This infiltrate was predominantly made up of lymphocytes and plasma cells, with some macrophages and neutrophils.
• The extensive presence of fungi was also noteworthy, with organisms varying in size from 50 to 500µm and displaying a thick outer capsule.
• The fungal organisms contained round basophilic endospores and eosinophilic spores. Some of these had been released into the surrounding stroma.
• The fungal manifestation was reported to be quite characteristic of a granuloma formed by Rhinosporidium seeberi, which results in rhinosporidiosis.

Possible Emergence of a Disease

• The study also referenced previous work by Leeming and others (2007), raising the possibility of rhinosporidiosis as an emerging disease in equines.
• This case, in combination with a previously reported fungal infection in a horse by Green (2007), adds potency to the argument of rhinosporidiosis emerging as a common disease in horse populations, particularly imports.