Cryptococcosis in Cats

Once a fungal infection has set in, it can turn into a systemic disease affecting multiple internal organs. It often spreads to the central nervous system, the skin (especially on the face and neck), the eyes, bone marrow, liver and kidneys. If these organs begin to fail, the infection can be life-threatening. There is a possibility that spores can infect an open wound, although this is rare. The upper respiratory aspect of the infection can progress into pneumonia. Granuloma masses can grow in the nasal cavity due to cryptococcosis. Veterinary attention is needed to relieve and cure a cryptococcosis infection in a cat.

The fungi Cryptococcus neoformans is a yeast-like growth that releases infectious spores into the air. It can be present in decomposing plant or animal material but is most often found in pigeon droppings. The spores cause severe upper respiratory and nasal problems in affected cats. Only a small number of exposed cats develop infection. Generally, these cats are suffering from a suppressed immune system. It is estimated that up to seven percent of all cats have cryptococcus spores present in their body, but only a very small amount of these cats will produce symptoms. 

Upper respiratory symptoms are the most common signs of a cryptococcosis infection. Other signs will become present as the infection progresses. It is important to identify this fungal infection before it starts to impact the function of major internal organs. Symptoms are as follows:

• Nasal discharge
• Sneezing
• Breathing difficulties
• Growths in the nostrils
• Swelling over the bridge of the nose
• Skin lesions
• Ulceration
• Depression
• Change in behavior
• Head tilting
• Circling
• Seizures
• Partial paralysis
• Dilated pupils
• Nystagmus (involuntary rapid movement of the eye)
• Blindness (caused by the retina detaching or other related issues)
• Loss of appetite
• Weight loss

As the cryptococcus fungus grows in decomposing organic material, all outdoor cats are at risk of exposure. Infection is generally a sign of an underlying immune system issue. All known factors of cryptococcosis infection are listed below.

• Exposure to infected soil
• Exposure to fowl manure
• Feline leukemia virus
• Feline immunodeficiency virus
• Genetic predisposition (as sometimes seen in the Siamese cat breed)

At your veterinary appointment, you will be required to provide your cat’s medical history to the vet. The veterinarian will then perform a complete physical examination to note all symptoms showing in the cat. Cryptococcosis can be easily diagnosed with a variety of tests. Cytologic evaluation of nasal or ocular discharge, skin scrapings or granuloma masses can provide a fast confirmation of cryptococcosis infection.

Gram stains may be useful to identify the fungus, as organisms will show as a crystal violet color, while capsules will turn light red, making an obvious distinction between the two. Wright stains, while more common, may be less effective as they can cause organisms to shrink and capsules to distort. Making an impression smear during staining can help for further examination of samples at a later time.

Biopsies of lesional tissue may also be helpful for the diagnosing process. Testing blood serum and urine can reveal secondary bacterial infections from open wounds and a suppressed immune system. FeLV and FIV should be tested for at this time.

The goal of treatment of cryptococcosis in cats is to rid the body of the infectious fungi. If an underlying cause of immune suppression is found, it too should be treated. Secondary bacterial infections should also be rectified to restore health to the cat.

Antifungal Medication 

A prescription of antifungal medication will be needed to eradicate cryptococcosis from the body. Medications such as fluconazole, itraconazole or ketoconazole may be prescribed for several months or more to eliminate the infection.

Antibiotics 

If a secondary infection is found in the body, the corresponding antibiotics will be prescribed to rid the body of the harmful bacteria. 

It is important to administer the full course of medication for treatment to be effective. You may need to monitor your cat for the development of side effects from the antifungal medication. Dosage of the prescription may need to be adjusted depending on the side effect severity. Follow-up appointments with the veterinarian will be necessary to evaluate if the infection is dissipating. 

The only way to fully prevent exposure to cryptococcus fungus is to keep your cat indoors. You need to prevent the cat from entering contaminated environments, especially damp structures. Infected droppings can emit spores for several years. Keeping your cat indoors will also shelter it from feline leukemia virus and feline immunodeficiency virus exposure.