Water Mold Infection (Pythiosis) in Cats

Pythiosis in cats is an infection caused by a fungus-like organism, Pythium insidiosum. This organism lives in stagnant water and swampy areas, and is commonly found in subtropical climates. Cats are infected when they ingest contaminated water or the organism enters the body through an open wound.

Pythiosis is rare in cats. The prognosis is guarded to poor, unless removal of all of the infected tissue is possible. In cats, the infection is less invasive than in dogs, but is still potentially life-threatening and as such must be considered an emergency.

Clinical signs vary according to the form of pythiosis affecting the patient. There are two main types of Pythiosis: Gastrointestinal and cutaneous.

Cats are more commonly affected with the cutaneous form, which presents with various types of skin wounds:

• Wounds that do not heal
• Lumps or nodules
• Ulcers on the skin
• Oozing or weeping skin sores

In some cases, serious complications develop such as obstruction of the intestine, or death of the intestinal tissue. Both may result in rupture of the intestine, with leakage of intestinal contents into the abdomen.

Cats come into contact with the infectious organism through ingestion of contaminated water or contamination of open wounds. Pythium insidiosum is usually found in stagnant waters.

High-risk areas are those with a sub-tropical climate (southeast Asia, eastern coastal Australia, South America, and parts of the United States, particularly in the Gulf Coast). In the US, the infection is thought to have a seasonal component, and is more active during late summer and fall months.

Diagnostics consist of a complete physical evaluation, and bloodwork. Diagnostic imaging, such as ultrasounds or X-Rays, are often necessary to detect how far the infection has spread. Other tests, such as biopsy of infected tissue or tests to identify fungal proteins are usually performed to identify the specific organism.

Treatment typically consists of the surgical removal of the affected tissues. For treatment to work effectively, it is fundamental that all affected areas are removed. In cases affecting the skin on the legs, amputation of the affected limbs may be necessary. After surgery, antifungal medications are prescribed for up to six months.

The prognosis in cats is guarded to poor, unless complete removal of all affected tissues is possible. With effective treatment, cats are usually able to fully recover.

Prevention consists of avoiding high risk areas, such as swamps or other sources of stagnant water.

Pythiosis is not contagious between animals or from animals to people.

Pythiosis is rare in cats

• Surgical removal of skin and GI lesions
• Antifungal therapy