Avoiding Parasites with Your Pets

Dog and cat in grass

Madison is such a great place to live, particularly if you have a dog. There are a lot of dog parks to explore, good neighborhood sidewalks to wander, lakes in which to swim, and some parks allow dogs to walk on the sidewalks. But with all these dog-friendly places, it is so important that we dog lovers are responsible dog owners. I’m sure many of us have been caught without a poop bag at one time or another. I’ve seen some people at dog parks look the other way when their dog is squatting. And I know the vast majority of dog owners don’t go out every day in winter to clean up their yard.

In the grand scheme of things, why does picking up poop really matter? What’s a few turds between friends? Not counting those of us who work in the veterinary field, most people find poop to be pretty gross. Nobody wants to step in it and smell it the rest of the day, and it detracts from a nice picnic in the park.

But besides the gross poop—gross in “that which can be seen”—there may be worse things in there that you can’t see. There are many parasites that are spread through poop that can infect other dogs as well as people. These are called zoonotic diseases and are the main reason you should pick up your dog’s poop after it has been deposited.

Do you have a new puppy? Roundworms are very common in puppies. They infect the pup in the mother’s womb and through her milk (roundworms encyst in muscle and “reactivate” in a pregnant dog). Roundworm eggs can be shed by puppies and kittens within three weeks after birth. Puppies with roundworms often have a pot-bellied appearance due to the spaghetti-like worms in their intestines and leave a soft stool, but adult dogs with roundworms may have no clinical signs at all. The eggs are passed in the stool and then into the soil. These eggs are highly resistant to freezing and chemicals, so they stay in the soil a long time. Rodents and roaches can ingest the eggs and be infective to a dog or cat that eats them. A dog or person that is romping on soil that contains roundworm eggs gets infected by licking their paws or sticking their fingers in their mouth. This is why children are more likely to be infected by roundworms than adults. In people, roundworms don’t make it into the intestines, but rather “get lost” elsewhere in the body, most often in the eye. Inside cats are also susceptible to roundworms, as the eggs can be found in potting soil.

Hookworms are another zoonotic parasite found in dog and cat poop. They are passed to puppies through the placenta and milk. Puppies and kittens with hookworms often have diarrhea, poor growth, and anemia, as hookworms attach to the inside of the intestines and suck blood. Adult dogs may just have intermittent diarrhea. Eggs deposited on soil are very resistant, but only develop into an infective larval stage when temperatures are above 59 degrees Fahrenheit—just about the time kids want to run outside in bare feet! You don’t need to ingest hookworm eggs to become infected. Infective larvae actually penetrate and migrate through the skin, causing very itchy, raised, winding tracts.

Intestinal worms in dogs can be prevented with monthly heartworm preventative or regular deworming regimens. Not all medications eradicate all types of intestinal parasites, so it is important to have your pet’s poop examined by a veterinarian to make sure they aren’t infected. A dice-sized amount of poop is mixed with a solution that makes parasite eggs float to the top. The sample is centrifuged and then examined under a microscope. The eggs are pretty to look at—well, to some of us, anyway—but veterinarians are always happy when none are found.

Giardia is a one-celled protozoal organism that can cause diarrhea in both mammals and people. The diarrhea will contain the Giardia organisms, which are then ingested by the next dog that might drink water in that location. Giardia is generally found in small pools of water or moist environments, especially areas where deer or raccoons might drink.

There are other parasites besides the ones that live in the intestines that can cause zoonotic diseases. Ticks are a big problem in Madison. They are found in brushy areas and stands of pine trees, and hitch rides on deer, squirrels, other mammals, turkeys, and robins. Ticks carry lyme disease, which can be very difficult to diagnose in people. There is a good blood test to detect lyme disease in dogs, however, and it also can pick up anaplasmosis and rocky mountain spotted fever. Knowing if your dog has been exposed to a tick-borne disease can help you be more diligent about covering up, checking for ticks after being outside, and using insecticides on both your pet and yourself.

Fleas are plentiful in this area, too. Besides potentially making your pet very itchy and infesting your house, they can also carry zoonotic diseases. Plague, currently more common in the western United States; typhoid fever; and cat scratch disease are all due to this small, blood-sucking insect. Fleas are also the intermediate host for tapeworms. If a cat or dog eats an infected tapeworm, they will develop the worms in their intestines. Children or adults who inadvertently swallow an infected flea can also develop tapeworms. There are many effective flea and tick repellants and preventatives on the market. Talk to your favorite veterinarian to decide which product is best for your dog and cat.

Please be a good dog owner and clean up promptly after your dog wherever you are. Parasite eggs can be in the soil even if you don’t see any poop at all, so remember to wash your hands and your kid’s hands after playing outside, gardening, or using potting soil. Use an effective flea and tick preventative on your pets so they aren’t bringing disease-carrying insects into your home. Other dog lovers, non-dog lovers, parents, children, and other outdoor enthusiasts will thank you! And maybe if we do a great job, all the parks in Madison will be open for dogs to walk through in the future.

Photo provided by Lori Scarlett, DVM

Lori Scarlett, DVM , is the owner and veterinarian at Four Lakes Veterinary Clinic. For more information, visit fourlakesvet.com .