indoor cats and parasites

 indoor cats and parasites
Posted by Dr. Kim Smyth on Apr 24 2013

If you think your strictly indoor cat is safe from parasites, think again. Both external and internal parasites can affect your indoor cat, even if he never puts a paw outside!


Fleas love living indoors. It’s warm and there’s always food available. Fleas can spend the winter in your house and you may not even know! This is because cats are fastidious groomers, and if they come across a flea, they might kill it – or snack on it! – before you or your vet can find them. But that doesn’t mean the danger is over.

Fleas are bad news for cats for multiple reasons.

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1. Fleas transmit diseases, such as Cat Scratch Fever and mycoplasmosis.

2. Fleas are the intermediate host for tapeworms, meaning if your cat eats an infected flea, she’ll end up with tapeworms, too.

3. Fleas feed on your pet’s blood, possibly leading to life-threatening anemia, especially in small cats and kittens.

4. Finally, some cats are allergic to flea saliva. Just one bite can send these cats into a scratching frenzy that often leads to superficial skin infections.

Internal parasites

Aside from the tapeworms mentioned above, other internal parasites like roundworms and hookworms can affect your cat, living and breeding in her intestinal tract. Typical transmission is via a fecal-oral route – when cats come into contact with feces that has parasite eggs in it, they can pick it up on their paws, for instance. Then when they lick their paws, they end up ingesting the eggs. It doesn’t help that parasite eggs are hardy – they can come into your house on the bottom of your shoe, too, and still stick around to make pets ill.

Some parasites use paratenic or transport hosts. Parasites progress to a certain point in their development in a paratenic host, such as a cricket or other bug, and then become dormant. When your cat eats the host cricket, the parasite will then develop into a mature adult in your cat’s intestinal tract.


If you have a dog, it’s likely that you have heard of heartworms and are giving a monthly preventive. But heartworm disease affects cats, too, even those who spend most of their time indoors. Heartworms are transmitted to pets by mosquitoes, but unlike dogs, there is no treatment for heartworm in cats. Because it only takes one mosquito bite to transmit heartworm disease, it’s important to protect your indoor feline family members, too – though we do our best to keep them out, stray mosquitoes do occasionally find their way indoors.

Tips to keep indoor kitties healthy and parasite-free:

1. Use a flea preventive year-round; topical and oral options are available.

2. Use a monthly heartworm preventive year-round, too. Though mosquitoes rarely rear their ugly heads in the winter months, it takes only a few warm days in a row for hungry mosquitoes to emerge. Some products combine flea preventive with heartworm preventive, making your job a piece of cake. As an added bonus, some heartworm preventives also contain dewormers that will treat intestinal parasites.

3. Bring a fresh stool sample with you when you take your cat for her annual (or semi-annual if she’s geriatric) veterinary exam so it can be checked for intestinal parasites.

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