Dear Most Esteemed and Knowledgeable Kitties:

My cat, Gracie, has worms (again). She had them for a while, then they seemed to go away for several months. Now they have come back. She is an inside cat but does go out occasionally. When she does, she occasionally eats grass. I changed her cat food about two weeks ago and was wondering if the food would be the problem. What do you recommend as a dewormer?

~ Stephen

Dipylidium tapeworm life cycle. Click to enlarge the image. Image courtesy of dr-dan.com

Siouxsie: Well, Stephen, there are several types of worms that infect cats, and each of them has a different vector for transmission.

Thomas: Tapeworms are the most common worms cats get. There are a couple of different species of tapeworm, and both of them require an “intermediate vector” to infect your cat. Dipylidium tapeworms need to grow to maturity inside a flea, and your cat gets infected by eating the infected flea.

Siouxsie: Taenia tapeworms require a rodent or rabbit as the intermediate host.  The worms live in those animals’ intestines, and a cat gets these worms by eating infected prey.

Thomas: You can tell your cat has tapeworms if you see little rice grain-type things around your cat’s anus or in her feces. Ooh, my bottom is itching just thinking about it! Yuck!

Siouxsie: But there are other species of worms common to cats, too. Roundworms, for example, are found in almost every kitten. They become infected through their mother’s milk, and this is why every kitten should be dewormed. But cats of any age can get roundworms because the eggs are often present in the soil.

Thomas: Roundworms look like spaghetti, and they can cause swelling of the abdomen, vomiting and diarrhea.

Siouxsie: Hoookworms are nasty little buggers. They can’t be seen with the naked eye, but severe infestations can cause anemia.

Thomas: Cats can get heartworms, too, but you won’t see them passing out of your kitty’s intestines.

Siouxsie: People used to think that only dogs got heartworms, but that’s just not true. Although heartworms  can’t thrive in cats, they can still cause serious problems.

Thomas: There are lots of over-the-counter dewormers, but they’re just not very effective. The worms have evolved to be immune to the medicine in the dewormers you buy at pet stores.

Siouxsie: What does this all mean to you, Stephen? It means that you need to take your cat to the vet for an exam. Bring a fresh sample of Gracie’s feces with you, too, so your vet can examine a sample under a microscope to check for parasites.

Thomas: Tapeworms won’t be seen in this microscopic exam, but if Gracie has any other kinds of worms. your vet will be able to see those.

Siouxsie: Your vet will give you a broad-spectrum dewormer. They’ll give Gracie one of the pills right at the office, and you’ll have to give the next one a couple of weeks later.

Thomas: If you can’t give Gracie a pill, I’m sure you could bring her back and a tech would give her the second dose.

Siouxsie: The best way to prevent tapeworms is to prevent fleas. Keep Gracie on a monthly flea-prevention medicine to keep her and your home flea-free.

Thomas: Again, you’re much better off getting one of the higher-quality (and higher-priced) flea control drops. Your vet will have a good idea which product is working well — trust me, it does change from year to year!

Siouxsie: The bottom line is, we don’t recommend any particular over-the-counter dewormer. We recommend that you get your cat to the vet and get her properly tested and treated.

Thomas: Good luck, and we’re sure your vet will be able to help you resolve Gracie’s worm problem. If you want to learn more about intestinal parasites, WebMD has a good article that gives more information about the various types of worms and their life cycles.