What Do Worms in Cats Look Like?

Worm infestations can sometimes be detected in a cat's fecal matter.

You love your cat and want it to be healthy. But lately it has been acting odd, or scratching a lot, or has potty problems. The cause may be one of many parasitic organisms generally called "worms." Learning to identify these pests on your pet can help you and your veterinarian decide the best course of action to make your cat healthy again.

Significance

There are several parasitic organisms called "worms," and most of them actually are worms. Though there are widely-available medications to prevent infection by worms, sometimes forgetting a dose, or particularly strong parasites, can invade and infect your cat. There are basically four types of worms: heartworm, roundworm, tapeworm and ringworm. Of all the worms, only ringworm is not a true worm, but all can make your cat ill and possibly kill it. Worst of all, these parasites can be unwittingly transmitted to humans (this is called a "zoonotic"--pronounced zoah-oh-naw-tick--disease or infection), though humans are atypical carriers for such creatures.

Types

One type of worm that can infect your cat is heartworms. The larvae of heartworms are carried by mosquitoes, so even indoor cats can become infected. Heartworms can nest in almost any part of the body, including the eyes, but usually congregate in the heart. Though they begin as microscopic organisms, heartworms grow and multiply quickly, displacing the areas in the hear that normally are used to pump blood. The heart therefore has to work harder, becomes enlarged, and eventually kills the cat.
Heartworms are long, thin and white-ish in color and it is highly unlikely that any owner will see the worms before it is too late. There are medications available for the prevention of heartworm, usually coming in 6 monthly doses at a time, and are prescribed (and usually sold) by your veterinarian. Treatment of hearworms is difficult because a poison is used to kill the heartworms, which may harm the cat. Additionally, even if the cat isn't killed by the poison, the dead bodies of the worms, or the sudden volume of blood, may strain the heart and result in the cat's death. Prevention, or at least early detection, is the key to successful treatment and survival of your cat.

Identification

Roundworms are a type of intestinal parasite that is very treatable. Roundworms are small, whiteish worms, like heartworms, but larger and rounder. Roundworm is very common in cats and often kittens get the microscopic eggs and larvae along with their mother's milk. Kittens adopted out of Humane Society shelters and responsible pet stores will document the vaccinations and treatments (usually a course of three over several weeks) that rids new kittens of roundworms. Kittens adopted privately, either from individuals or independent shelters, should receive roundworm treatment from a veterinarian.
Roundworms enter the body of a cat in two ways. First, though infected food sources such as an infected mother's milk. Second, by being in contact with infected fecal matter; other cats, dogs, raccoons, and/or opossums are common sources. The worms enter the digestive tract where they grow a little and breed. They then enter the blood stream to the lungs and are coughed up (and swallowed) to go through the digestive system all over again. The entire time, they grow and feed, and can eventually kill your cat through compromise of their respiratory system, their bloodstream, or other associated infections. Roundworms in these cases are treated by two rounds of a poison; the first kills the worms living in the digestive tract and the second (administered about two weeks later) kills the remainder. The cat then defecates the dead worms out (which look like thin spaghetti).

Size

Tapeworms also begin as microscopic eggs and larvae, but eventually grow to become the largest of all the parasitic worms. Full grown tapeworms can be as long as the intestinal tract of its host; several feet long in a cat, several meters long in a human, and dozens of meters long in a horse. Tapeworms are flat, long worms with segmented bodies (a defense mechanism) with a round head that has sharp, pointed teeth. Tapeworms can enter the body in several ways, but are usually ingested from dead creatures your cat may catch or be fed (uncooked fish, for example). Once hatched, tapeworms latch onto the intestinal wall with their teeth and absorb nutrients that pass through the intestines. They continue to grow through the addition of more segments. These segments can be detached if they are pulled, so it is never advisable to pull a tapeworm out of your cat's anus.
Tapeworms are also susceptible to poison, which is administered by the veterinarian, possibly in several doses if the tapeworms are numerous or if it is particularly resistant to poison.

Misconceptions

"Ringworm" is not a worm at all, but a fungus. The reason it is called ringworm is the fungus forms a circular infection on the skin of the animal, causing the hair to fall out, revealing a worm-shaped ring on the skin. Most ringworm is caused by contact and is very contagious. There is prescription medication available from your veterinarian that can treat ring worm over the course of several days, or weeks, depending on the level of infection. Ringworm depresses the immune system of your cat and can allow secondary infections to occur, so treatment is highly recommended. Additionally, the cat is repulsive to look at, which may be an extra motivator.
Ringworm does pass very easily to humans. If you handle your cat, do so with rubber gloves that are disposed of immediately afterward. Wash your hands in a bleach solution as regular soap and water is inadequate to remove ringworm (even so-called "anti bacterial soap"); the bleach solution should be 1 cup bleach to 10 cups water in order to ensure an effective kill of the spores.

Prevention/Solution

The best method to prevent infection from all kinds of parasites, including hookworm, whipworm, giardia, and those described above is through prescription medication purchased from your veterinarian. Though the price may seem steep--as of 2008, an average of $60 for six months of heartworm protection, $120 for a years' supply of anti flea, tick, and mosquito treatment--prevention is much less expensive than treatment after the fact. Also, considering that many of these parasites and infections can and do make the leap from pets to humans, the result may be saving your family from doctors' bills on top of veterinary bills.

Resources

• Pet Center: Worms
• Pet Center: Heartworm in dogs
• Pawprints and Purrs, Inc.: Intestinal Parasites