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Intestinal Parasites in Cats

Intestinal Parasites of Cats

95% of kittens are born with intestinal parasites, and many adult cats have them, too. Dewormers kill only the adult worms living in the intestinal tract, but do not kill larval worms hiding elsewhere in the body. For this reason, cats frequently flare up with parasites despite being dewormed as kittens. It is very important to realize that cats do not have to be exposed to intestinal parasites as adults in order to have them. They tend to have a few all their lives and can reinfect themselves even as adults. Cats who hunt or have fleas also acquire new parasites as well. All cats should be checked regularly for parasites. 

Internal parasites are diagnosed by having a fresh stool sample examined under a microscope by someone here at the veterinary hospital. This should be done as part of a health exam when your obtain a new kitten or cat, and on a yearly basis as part of your cat’s annual health exam and vaccinations – even for indoor cats. 

Try to collect the freshest sample you can and keep it refrigerated until you can bring it in to the veterinary hospital. Stool samples will keep up to 24 hours if kept cool (NOT FROZEN).  

So that you may better understand the problems internal parasites can cause and what signs to look for, we have included a short description of the five most common types of internal parasites.

ROUNDWORMS: The most common type of worm. They are 2-3 inches long and resemble strands of spaghetti. They live in the small intestine, and may cause vomiting, diarrhea and weight loss. This parasite is most commonly transmitted via the stools of other cats or dogs, or from eating mice or other rodents which may harbor infective larvae of the worm. Mother cats can also pass these worms to their unborn kittens. Almost all kittens have them, and the larval worms can remain dormant for years, then revive to cause active infection in an adult cat. 

​HOOKWORMS: ​Hookworms are small, fine worms which attach to the walls of the small intestine and live by sucking blood from the cat. They cause severe diarrhea, which may be bloody, and anemia, especially in kittens and young cats. Hookworms are usually transmitted by infested stools of other cats or dogs, or via the uterus or mother’s milk. 

TAPEWORMS: Tapeworms also live in the small intestine, where the head attaches to the intestinal wall and produces a chain of segments. Mature segments containing eggs are passed with the stool, or may be seen around the rectum. They resemble small grains of rice. They may be acquired through the ingestion of rodents or birds.

COCCIDIA: Are one celled protozoal parasites, more like bacteria rather than “worms.” Kittens can pick these up from their mother and they can be acquired by eating rabbit or other wildlife droppings. They are treated with antibiotics. 

GIARDIA: Are also protozoans. They are very difficult to pick up on a regular stool check. Antibiotics or special wormers kill them but they are difficult to eradicate completely and often flare up with stress or other intestinal problems. They are contagious to humans and cause vomiting and diarrhea in both people and pets.

TOXOPLASMOSIS: This is a protozoal infection that occasionally causes diseases in cats. It is also dangerous to a fetus if a pregnant woman contracts the disease during pregnancy. Although most people get this disease from handling raw meat, and it usually doesn’t cause symptoms in healthy pets or people, it may still be a concern for cat owners. Please tell us if you are pregnant or immune suppressed and we can give you more information on this topic. 

If a stool sample is positive for parasites, the veterinarian will prescribe an effective dewormer. We usually recommend deworming twice, two weeks apart. Please weigh your animal before picking up any wormer, to ensure that the proper dose is given. A stool sample should be checked again 4 to 8 weeks later, to ensure that your pet is not being reinfested by his or her own environment. Clean the litter box daily as well.