What is cryptococcosis?
Cryptococcosis is a common infectious disease caused by the yeast-like fungus Cryptococcus neoformans. This fungus is widespread in the environment and cats (humans, dogs and other animals can also become infected) acquire it by inhaling spores. It is much more common in cats than dogs.
The organism is worldwide in distribution and is commonly found areas contaminated with bird (especially pigeon) droppings, although many infected cats have no known contact with pigeon droppings.
Immunocompromised cats such as those infected with FeLV or FIV are especially vulnerable to infections such as cryptococcosis.
Infected cats do not pose a risk to humans. Infection is acquired by inhalation of the fungus and not spread from animals or humans.
Once inhaled, the organism typically colonises in the upper respiratory tract (usually the nasal passages).
What are the symptoms of cryptococcosis in cats?
Common symptoms of cryptococcosis include:
- Sneezing and snuffling
- Raspy breathing
- Nasal discharge
- Hard, nodular skin swellings, most often over the bridge of the nose
- Skin lesions on the head
- Swollen lymph nodes
- Loss of appetite
Other symptoms may be present depending on what organ systems are involved. These may include;
- Neurologic abnormalities (seizures, incoordination, behavioural changes)
- Eye disorders (chorioretinitis; inflammation of the choroid and retina of the eye)
How is it diagnosed?
Your veterinarian will perform a complete physical examination and obtain a medical history from you. Diagnosis is based on identification of the organism and tests he may perform include:
- Inspection of the nasal discharge, cerebrospinal fluid or skin lesions by India ink stain.
- Latex agglutination test (LAT) to detect antigens from the capsule of the fungus. False negative tests may occasionally occur in cats with localised infection. False positives also occasionally occur.
- Radiography of the nasal cavity may be useful.
Your veterinarian may also wish to perform CBC/biochemical profile/urinalysis, FIV and FeLV tests to gain an insight into the general health of your cat.
How is it treated?
Itraconazole is the drug of choice for treating cryptococcosis. This should be given with a fatty meal to enhance absorption of the drug.
Fluconazole if there is CNS involvement.
Surgical removal of the lesions in the nasal cavity.
Supportive care such as a feeding tube if necessary.