Rhinosporidiosis in Dogs
Rhinosporidiosis is a very rare chronic (long-term) infection that typically occurs in the mucous membranes of dogs. It most commonly occurs in the nose and nostrils, but can also take hold in the nose and eyes. Rhinosporidiosis belongs to the zoonotic class of fungal infections, meaning that it can be transmitted to humans.
Symptoms and Types
Signs and symptoms of rhinosporidiosis include the following: sneezing, bleeding, wheezing, or labored breathing; an infection of the nostrils with a cauliflower-like growth; a polyp or other growth located near or on the nostril - this growth may be white or yellowish in color and may appear speckled or spotted because of the fungus associated with the growth.
Humans will sometimes contract a form of this infection. In instances like this, one might notice a small growth or polyp on the reproductive organs, including the penis or vagina, or a growth along the ears or near the eyes. However, this type of fungal infection is exceedingly rare in dogs, and even more so in human beings.
The primary cause of rhinosporidiosis is infection with the fungus rhinosporidium seeberi. Risk factors include frequent exposure to stagnant or standing water, and living in a dry and dusty climate.
The best way to diagnose an infection caused by rhinosporidium seeberi is by examining the polyp or nasal growth, or examining the abnormal cells caused by the fungus. Your veterinarian can do this by removing the polyp, or by removing part of the affected tissue for bioptic examination.
Your doctor may also find it necessary to order a radiograph or x-ray of the nasal cavity; however, these typically will return as normal, as will other types of tests, including urine tests and blood tests.
The fungus responsible for this rare type of infection may show up on other types of findings, including what are known as histopathologic findings. These include diagnostic tests of epithelial or skin cell analysis, and testing of organisms in the surrounding tissues. A medical professional may excise or cut away the mass, or perform a rhinotomy, which involves cutting into part of the nose to remove the infected tissue.
To confirm a diagnosis, your veterinarian will usually confirm the pathologic findings, which will typically show ulcers in the skin cells, an abnormal increase in the number of cells within the tissue surrounding the nose or nostril, and fibrous tissue surrounding the nasal cells. Lab testing will show an inflammatory reaction within the skin cells if the fungal organisms are released into the surrounding skin and nasal tissue, making identification of the fungus possible.