Internal Feline Parasites
A parasite is an organism that lives and feeds within or upon another organism or host at the host’s expense, sometimes causing disease or even death.
Internal feline parasites afflicting cats may be one-celled organisms called protozoa or multiple¬ celled wormlike creatures. Because many internal parasites spend a portion of their life cycles within the cat’s digestive tract, they are discussed here along with other digestive problems that afflict cats. However, the disease they cause may affect other parts of the body as well.
Roundworms are a common problem in cats; in fact, most cats are infected with roundworms at some point in their lives, usually as kittens. The adult worms that reside in the small intestine usually do not cause many problems for the cat, but if the concentration is large, especially in kittens, vomiting or diarrhea, and a scrawny, potbellied appearance can result. Roundworms, which resemble three¬ to four-inch-long pieces of spaghetti, are sometimes visible in a cat’s vomit or stool.
Cats can be infected by ingesting roundworm eggs that have been shed in the feces of an infected cat (the eggs can last for years); by eating a rodent carrying the parasite; or, most commonly, by ingesting milk from an infected mother. Diagnosis and treatment are simple; many safe, effective, and inexpensive oral medications are available.
A word of caution to cat owners with young children: By ingesting roundworm eggs, humans can acquire a condition called visceral larva migrans, which sometimes leads to muscle or joint pain, abdominal pain, coughing, skin rashes, or seizures; if the larvae reach the eye, vision may be impaired. Keep toddlers away from the litter box, and prevent children from playing outside in soil that may be contaminated with dog or cat feces. Timely and routine treatment of all kittens and new cats with medications that kill roundworms is a crucial preventative measure.
Hookworms enter their host in the larval stage through the mouth-in contaminated feces or in the milk of an infected mother-or by penetrating the skin. Some infected cats develop diarrhea, but the major problem caused by this intestinal parasite is anemia. Adult worms residing in the intestine survive by sucking blood from their host, and if there are enough worms, there can be significant blood loss; kittens tend to be most severely affected. Your veterinarian can easily diagnose and treat hookworm infections with orally administered medications.
Hookworm larvae can tunnel through human skin and cause a condition called cutaneous larva migrans, which causes extreme itchiness. Avoid close contact with soil or litter contaminated by the feces of hookworm-infected cats.
Tapeworms are segmented worms that commonly afflict cats but rarely cause them problems. Owners, however, may be quite alarmed by the sight of the rice-size tapeworm segments crawling near their cat’s rear end. Dried segments that look much like large sesame seeds can be seen clinging to the fur around the anus. Cats are infected by ingesting a flea or rodent carrying the immature stage of the parasite. Treatment is simply and effectively carried out by administering medication either by injection or by mouth, but unless owners control fleas and prevent their cats from hunting, reinfection will occur.
Coccidia are single-celled parasites that commonly afflict kittens and young cats through contact with infected feces. Most of the time the infection causes no particular health problems, although di¬arrhea can occasionally result. Treatment with oral medication is usually simple and straightforward.
Giardia are another group of protozoan parasites spread by the ingestion of contaminated water or feces. Infection may cause diarrhea, or it may cause no disease at all. Simultaneous treatment of all cats in the household with oral medication is usually necessary to eliminate the infection, and treatment must sometimes be repeated several times. Litter boxes should be changed and disinfected more frequently. It is not certain whether giardia infections can be transmitted from cats to humans. People who are living with or treating infected cats should wash their hands thoroughly after handling the cat or the litter box.
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