Fungal Infection (Cryptococcosis) in Dogs

Cryptococcosis infection can be contracted worldwide, but is most common in the western U.S., Canada, and Australia.

In dogs, the infection is often disseminated, meaning it affects multiple organs, including the respiratory tract, the central nervous system, and the eyes.

Cryptococcosis is most commonly seen in cats and is relatively rare in dogs.

If the infection reaches the central nervous system, the prognosis is guarded and the infection is potentially life-threatening. Neurologic symptoms in dogs, including seizures, paralysis, and lack of coordination, must be considered an emergency requiring urgent veterinary care.

Factors such as recently disrupted soil or an already compromised immune system can increase the risk of contracting cryptococcus.

Usually, the infection is spread through fungal spores that are found in soil. The fungus can also be found in avian droppings. Infection may occur through inhaling or ingesting the spores. Rarely, infection occurs through contamination of open wounds.

Symptoms vary according to the location of the infection. It usually affects the skin and the upper respiratory system.

If the infection affects the brain, spinal cord, or nerves, neurological symptoms can occur.

Neurologic symptoms are always an emergency requiring immediate veterinary attention.

The diagnostic process starts with the observation of symptoms and the findings of a complete physical examination. Additional tests include bloodwork and specific neurologic, ophthalmologic, or dermatologic evaluations. Diagnostic imaging such as X-Rays, CT scanning, or MRI might also be necessary to determine whether the infection spread throughout the body. Specific exams to identify the fungus include cerebrospinal fluid analysis (CSF, aka spinal tap), biopsy or cytology of affected tissues, and specific tests to determine the presence of fungal proteins.

The treatment of choice is usually antifungal medications. Therapy might require over a year to fully clear the infection, and routine checks and bloodwork are required to monitor for side effects of the medication and possible complications.

Cryptococcus can be a dangerous infection. In dogs, the survival rates are generally high, but if the central nervous system is involved, the risk of death increases significantly. Some dogs with infection of the central nervous system may require lifelong medication to keep the infection under control. Patients with central nervous system infection may have lifelong neurologic deficits and seizures.

Cryptococcosis is not directly contagious between animals. Prevention involves reducing exposure to possible risk factors such as disrupted soil, especially in high-risk areas.

Cryptococcosis mostly affects cats and is relatively rare in dogs.

• Antifungal medications
• Monitoring