Feline roundworms live in a cat's small intestinal tract. A cat can be infected in one of several ways, including ingesting eggs from the soil, ingesting a rodent (like a mouse or squirrel) that is infected and through nursing from an infected mother cat. Roundworms can be successfully eliminated in cats.
Common name: Roundworms
Scientific name: Toxocariasis, Ascariasis.
All cats can be infected with roundworms, but kittens under 6 months old are most commonly infected.
Roundworms are a very common intestinal parasite, and most kittens will be infected.
Roundworms are found worldwide, though a higher incidence of roundworm infections is found in the southeastern United States.
Clinical signs (primary, most to least frequent, scientific term, synonyms)
Silent infection (no clinical signs noted), Diarrhea, Potbelly, Vomiting.
Clinical signs (secondary, most to least frequent, scientific term, synonyms)
Dull, dry hair coat, Intussusception (telescoping one part of the intestine within another part causing an obstruction), Pneumonia, Aberrant larval migrans (the larval worm gets ‚Äúlost‚Äù and causes injury to an organ like the brain or eyes).
Causes (scientific, common term)
Toxocara cati (cat roundworm), Toxascaris leonine (roundworm), Bayliascaris procyonis (raccoon roundworm).
Organ systems affected (most to least affected)
Small intestine, Hair coat, Aberrant organ damage, especially to the brain or eyes.
Fecal flotation (a test to identify parasite eggs or one-celled organisms ‚Äî giardia, coccidia ‚Äî in the fecal material).
Infection from other parasites (hookworms, giardia, or coccidia), Feline panleukopenia, Intestinal obstruction from a foreign body (like a string, toy, etc.).
Feline roundworms live in a cat's small intestinal tract. Ascariasis or toxocariasis is the medical term for a roundworm infection. There are two different species of roundworms that can infect cats, Toxocara cati and Toxascaris leonine. All cats can be infected with roundworms, but kittens under 6 months old are most commonly infected.
Roundworms are found in all 50 United States but are most prevalent in the Southeastern United States. Cats can be infected with roundworms in several ways. Most kittens become infected through nursing from an infected mother cat. This is known as transmammary infection. Weaned kittens and adult cats can become infected by ingesting an infected rodent (like a mouse) or ingesting feces or soil contaminated with roundworm eggs.
Most infections are mild and do not produce clinical signs. Heavy worm burdens can lead to diarrhea, a potbellied appearance or a dull, dry hair coat. Cats may vomit worms, or worms may be seen in a bowel movement. Roundworms look like spaghetti and are long and white. Worms can cause an intussusception, where the intestine telescopes, leading to an obstruction. Rarely, the larval worms do not go to the intestine but migrate to other parts of the body. This can cause damage to organs such as the brain and eyes.
Especially in kittens, pneumonia and coughing sometimes occur if a large number of larval worms are in the lungs. Roundworms are considered a public health concern because they can infect humans, especially children. In humans, the disease is known as visceral larva migrans, as the worms commonly infect the eyes, brain, liver and lungs. The damage to eyes or other organs is permanent.
A clean environment is most important in preventing infection. Clean litter boxes or remove feces from the lawn daily. Teach children proper hygiene. Keep all sandboxes covered to prevent resident and feral (wild) cats from using it as a litter box. Once the environment is contaminated with roundworm eggs, the infective eggs remain in the environment for years.
A veterinarian will perform a fecal flotation to diagnose roundworms and other intestinal parasites. The veterinarian will prescribe a wormer to treat roundworms and any other parasites. Most infected cats will require more than one worming. Breeders should consult with their veterinarian about the best wormer for a pregnant or nursing cat. Routine fecal flotations are recommended once or twice a year, depending on the cat's environment and reproductive status.
Diagnosis and an appropriate deworming plan for an individual animal should be made by a veterinarian. Many pets have multiple parasites, and the appropriate wormer, or interval of worming, will not be the same for all cats. Owners should remove all fecal material daily to decrease the risk of infection to the cat and to humans.
Most cats infected with roundworms will have minimal problems. Routine deworming will prevent most problems.
Taylor, K. Roundworm Infection. In: Cote, E., ed. Clinical Veterinary Advisor: Dogs and Cats. Saint Louis: Mosby, 2007; 979-80.
Blagburn, B.L., Lindsay, D.S., Vaughan, J.L., et al. Prevalence of Canine Parasites Based on Fecal Flotation. Comp Cont Educ Vet Pract, 1996; 18: 483-509.
Parsons, J.C. Ascarid Infections of Cats and Dogs. Vet Clin North Am Small Anim Pract, 1987; 17: 1307-39.
Center for Disease Control Division of Parasitic Diseases. Guidelines for Veterinarians: Prevention of Zoonotic Transmission of Ascarids and Hookworms of Dogs and Cats. http://www.cdc.gov/ncidod/dpd/parasites/ascaris/prevention.htm.
Charlotte Means, DVM, MLIS
Steven Hansen, DVM, MS, MBA
© 2007. The American Society for the Prevention of Cruelty to Animals (ASPCA)