Rhinosporiodosis

Rhinosporidiosis is a chronic granulomatous infection of the mucous membranes that usually manifests as vascular friable polyps that arise from the nasal mucosa or external structures of the eye.

Initially described by Seeber in 1900 in an individual from Argentina, rhinosporidiosis is endemic in India, Sri Lanka, South America, and Africa. Cases from the United States and Southeast Asia, as well as scattered occurrences throughout the world, have also been reported. Most cases of rhinosporidiosis occur in persons from or residing in the Indian subcontinent or Sri Lanka. In addition to humans, rhinosporidiosis has been noted in cats, cattle, dogs, ducks, goats, horses, mules, parrots, and swan.

The etiologic agent, Rhinosporidium seeberi, has never been successfully propagated in vitro. Initially thought to be a parasite, for more than 50 years R seeberi had been considered a water mold. Molecular biological techniques have more recently demonstrated this organism to be an aquatic protistan parasite, and it has been placed into a new class, the Mesomycetozoea, along with organisms that cause similar infections in amphibians and fish. This reclassification is not without controversy, as other researchers have presented data that R seeberi is a cyanobacterium, further demonstrating the difficulties that arise when working with pathogens that cannot be maintained in the laboratory setting. Other molecular work has demonstrated evidence that R seeberi may have host-specific strains (eg, human vs dog vs swan).