Raccoon disease in cats is termed, Baylisacaris procyonis, and is a lethal intestinal nematode. Contraction of raccoon disease will cause severe ocular and neurological signs to those infected, as the larvae migrate from the small intestine. Although infectious to cats, dogs, birds and humans, the Baylisacaris roundworm causes no aliments to the adult raccoon species. Select mammals can become infected with raccoon disease by direct contact or ingestion of the Baylisacaris eggs. Nematode eggs are shed into the environment through the fecal matter of an infected raccoon to be passed to a permanent or intermediate host such as a bird or rodent. Infestation of Baylisacaris procyonis in cats is rare, but often fatal.

Raccoon disease is an infection of a species of roundworm that uses the raccoon as a permanent host. Raccoons are relatively immune to this internal parasite, but felines that contact this roundworm experience severe inflammatory processes caused by tissue damage. Invading the brain, central nervous system, and even the eyes of a feline, raccoon disease is a very serious condition that often causes death. A feline can easily be infected by licking the microscopic eggs off her paws after a walk outside or by consumption of an intermediate host such as a mouse or bird.

The Baylisacaris procyonis roundworm is relatively large, ranging from 15-20 cm in length and 1 cm in width, causing a great deal of tissue damage as they migrate. The cat’s body naturally responds to the damage with inflammation and recognizable symptoms begin to appear as early as two to four weeks after ingestion. Symptoms of raccoon disease depend on where in the cat the worms are present and can include any of the following: 

Raccoon disease in cats is caused by direct contact with nematode-contaminated feces or ingestion of the Baylisacaris procyonis eggs and larvae. Baylisacaris eggs are shed through the feces of a contaminated raccoon and remain in the environment until they infect a host or intermediate host. An outside feline or a feline that leave the home to defecate, can pick up microscopic Baylisacaris eggs of the pads of the feet. The feline naturally licks her feet clean after coming inside the home and ingests the eggs, infecting herself with raccoon disease. Natural feline prey, such as rats, mice, and birds can also be intermediate carriers of the Baylisacaris procyonis roundworm. When a feline eats one of these infected intermediate hosts, the cat then infects herself with the raccoon disease roundworm. 

Diagnosis of raccoon disease in cats will begin with a physical examination, review of the feline’s medical history, and a comparison of notes with the pet owner. The physical signs the feline is displaying most likely will not be enough for the veterinarian to make a proper diagnosis, therefore, additional testing will be required. As the symptoms associated with raccoon disease are primarily neurological, your veterinarian may ask for an x-ray or CT scan of the feline’s head. Blood work and a urinalysis are also common diagnostic tests, as present symptoms may also indicate a possibility of complications to the internal organs. 

In felines, a fecal examination may prove to be the most efficient diagnostic test for raccoon disease. A test called a fecal flotation test is likely to be conducted as Baylisacaris procyonis eggs are shed in the feces and are visible under the lens of a microscope. The fecal floatation test is noninvasive and only require a small sample of your cat’s feces.

An effective treatment for raccoon disease in cats currently does not exist. Various studies have been done in the past using anthelmintic drugs commonly used on other species of roundworm, but the effectiveness of these drugs on Baylisacaris procyonis larvae is undetermined. Your veterinarian may treat your cat’s disease with heartworm medication, milbemycin oxime, or other internal parasite treatment drugs such as flubendazole, fenbendazole, albendazole, moxidectin, ivermectin, pyrantel, or piperazine. The inflammatory damage to the cat’s tissues is permanent, but symptoms can be treated with corticosteroids and pain medication. 

Raccoon disease is a very serious and often fatal disease in cats. Damage to the body’s tissues, especially the central nervous system, is often permanent and the veterinarian may suggest euthanasia. Preventative methods should be put in place to prevent your cat from contracting raccoon disease such as keeping raccoons away from your home and discouraging the feline from consuming prey animals.