Worms are Yucky- Pet Parasite Prevention

Yesterday a cat came into our practice for vomiting- the presence of squiggling spaghetti like worms in her vomit prompted the anxious visit. Because roundworms eggs can infect humans, and there were small cute children in the exam room, we had a tense and stressed conversation about zoonotic disease (diseases that pass from animals to humans) and parasite treatment and prevention.

Dogs and cats, especially cats that go outside and hunt, are exposed to intestinal parasites that can make them sick and that can also be transferred to humans. Decades ago, there were few medications for parasites, and dogs and cats stayed outside the house to ensure they didn't infest their owners. Now, with pets in the house and often in the bed, preventing infection is essential for both pet and human health. Thankfully safe and effective medications, both for the treatment of existing infections and the prevention of new ones, are available.

Puppies and kittens are often born with worms, which can pass through the placenta and through their mother’s milk.

All dogs and cats should be dewormed several times as infants. Stool samples need to be checked in addition, because the basic broad spectrum deworming medication can’t treat every single type of parasite. More specific medications are used to treat infections like coccidia, giardia, or tapeworm. Stool samples can come back “negative”- meaning no parasites seen- even if a pet is infected with worms because adult female worms need to be laying eggs at the time that the stool is produced for there to be eggs in the sample. 

In humans, the worms do not complete their life cycle as they do in their normal host. After being ingested through contaminated soil, food or dirty hands, roundworm larva travel through the body, especially through lungs, the nervous system and eye. Unsurprisingly small children are most at risk because of their questionable personal hygiene habits. Hookworms are transmited from soil, or sand, and travel underneath the skin, leaving itchy tracks. 

Our patient, the worm spewing cat, was given a deworming medication to rid her of the current infestation of worms. She will start on a monthly topical medication to prevent future infections. And the cute little girls living with their pet cat, who probably play in the dirt and don’t wash their hands like a surgeon, are protected too.


Dr. Astrid Kruse graduated from Tufts University Cummings School of Veterinary Medicine in 2003. After completing a year long rotating small animal medicine and surgery internship, she joined the staff at a large general practice hospital on the North Shore, where she enjoyed forming long term connections with her patients and clients. She is happy to be a part of the team at Domino Veterinary Hospital in Concord, MA. Her special interests include dog and cat internal medicine, preventative health care, rabbit and guinea pig medicine, soft tissue surgery, and dentistry in all species.