Pets, parasites and You — Important things to know

Dogs and cats are not just pets but are members of the family. And like any member of your family, it’s essential to keep your companion animal healthy and free of parasites.

Most pet owners are unaware that their furry friends are infected with worms unless they see one. Most internal parasites are too small to be seen by the human eye. It is quite common for a dog or cat to become infected with an internal or external parasite at some point in its lifetime. Parasites can impact your pet in a variety of ways, ranging from simple irritation to causing life-threatening conditions if left untreated.

Some parasites can even infect and transmit diseases to you and your family.

Zoonotic disease

Zoonotic disease is one that can be passed from pets to people. People often worry about the possibility of infection for themselves or family when a pet is diagnosed with intestinal parasites, such as worms. This concern is valid because several intestinal parasites are considered zoonoses.

Roundworms are one of the most common intestinal parasites seen in both dogs and cats. In fact, most puppies and kittens are born with roundworms. Roundworms have the potential to be passed to people. Children are at highest risk for infection with roundworms.

Hookworms are another common parasite in dogs and cats. They also are a zoonotic parasite and can be passed from pets to people.

Hookworm infection in human beings

Tapeworms are considered zoonotic parasites. However, typically, they are not passed from dogs or cats directly to people. Dogs or cats need to get infested with fleas to get infected with tapeworns or they need to hunt and ingest a small prey animal. Humans get infected by eating uncooked meat or fish that is infected.

Trichenella is another intestinal parasite that can be transmitted only by eating uncooked or undercooked meat infected with the parasite, most often pork or wild animals.

Toxoplasma is a parasite that is frequently found in cats. It is a serious threat particularly for a pregnant woman and her fetus.

How are internal parasites passed?

Intestinal parasites can be passed to people in several different ways.

Some intestinal parasites are transmitted to people through ingestion of feces from infected animals or ingestion of contaminated soil or water. Examples include roundworms, hookworms, Giardia and Toxoplasma.

Some can be passed when the larvae of the parasite contact uncovered skin. Hookworms can be transmitted this way.

Other intestinal parasites are transmitted by eating uncooked or undercooked meat that is infected. Certain types of tapeworms, as well as Trichinella, can be passed in this fashion.

Fortunately, in most cases, by taking simple precautions like practicing good hygiene and making sure all meat is cooked thoroughly before eating it, infection with zoonotic intestinal parasites can be avoided


Heartworms can be a very serious problem for both dogs and cats, especially those in mosquito-infested areas, as mosquitoes are a vector and intermediate host for the pest. Heartworms can kill or severely debilitate pets infected with them. That’s because heartworms live in the bloodstream, lungs, and heart of infected pets. Your veterinarian can do a blood test to determine if your pet has heartworm disease. A year-round preventive program is most effective to keep pets free of heartworms.

Fleas and ticks

Fleas and ticks can carry and either directly or indirectly transmit several potential illnesses. For example, rickettsiosis can be transmitted directly by ticks to humans. Bartonellosis is transmitted between cats by fleas and then may spread to people. Also, fleas serve as an intermediate host for tapeworms, which can infect both pet and humans.

Reducing risks for your family

You can reduce the risk of parasitic infection to your family by eliminating parasites from pets; restricting access to contaminated areas, such as sandboxes, pet “walk areas,” and other high-traffic areas; and practicing good personal hygiene.

Disposing of pet feces on a regular basis can help remove potentially infective worm eggs before they become distributed in the environment and are picked up or ingested by pets or humans.

Year-round prevention

Parasites can infect your pet any time of year. External parasites, such as fleas and ticks, may be less prevalent outside during certain times of the year; however, they often survive in the house during the winter months, creating an uninterrupted life cycle. Other internal parasites, such as worms, may affect your pet all year long. That’s why it’s important to consult with your veterinarian to implement a year-round parasite control program.

What can I do?

Responsible pet parasite control can reduce the risks associated with the transmission of parasitic diseases from pets to people. By following a few simple guidelines, pet owners can better protect their pets and their family.


Quick tips

*Practice good personal hygiene

*Use a preventative flea and/or tick
treatment year-round

*Only feed pets cooked or prepared food (not raw meat)

*Minimize exposure to high-traffic pet areas

*Clean up pet feces regularly.

*Visit your veterinarian for annual testing and physical examination

*Administer worming medications as recommended by your veterinarian

*Ask your veterinarian about parasite infection risks and effective year-round preventative control measures administered monthly