Cryptococcosis In Cats Symptoms and Treatments

Cryptococcosis is caused by a fungus, Cryptococcus neoformans, which is widespread in the environment and can infect cats, dogs, and people. While this fungus is widespread, it infects a relatively small number of animals. It is primarily a problem in animals that have a deficient or suppressed immune system. This fungus is well known in human medicine as the disease that infects up to 20% of AIDS patients. The organism is relatively easy to diagnose and treatment can be performed successfully if instituted early.

Pets and people contract the cryptococcus infection primarily by inhaling the fungal particles. After the particles are inhaled, they can take up residence in the nasal cavities or lungs. Some studies have shown that in a population of healthy dogs up to 14% of them had Cryptococcus present in their nasal cavities. In a similar study of healthy cats, up to 7% contained the organism in their nasal passages.

After cryptococcus reaches the lungs or nasal cavity, it can do one of several things. In most healthy animals, the fungus remains isolated and never creates any symptoms of problems. In animals with a suppressed immune system, e.g., from excessive steroid use, the disease can progress and create granulomas, pneumonia, or systemic disease and symptoms. In addition, cats that have immunosuppressing diseases such as feline leukemia or FIV are also more likely to develop severe disease.

Cryptococcosis is treatable with itraconazole, fluconazole or ketoconazole. Following the concepts of therapy that have evolved for human cryptococcosis, the obvious choices would be fluconazole and itraconazole. The progress of the disease and response to antifungals can be serologically monitored. Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) might be sought as underlying diseases that could affect the prognosis or required duration of therapy.

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