Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Scooping Poop Keeps Parasites at Bay


Pet Column for the week of May 29, 2006


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Kim Marie Labak
Information Specialist

Have you ever walked away from a pile your pet has left on public property? Have you gone days, or even weeks, without picking up your pet's piles in the back yard? Many pet owners do not realize that cat and dog feces carry parasitic worms capable of infecting humans.

Not only is picking up after your pet hygienic, lawful, and courteous, but it can also help keep the soil free of parasites such as roundworms and hookworms and can help keep humans safe from infections. In addition, keeping pets on a regular worm preventive and practicing good hygiene can help control and prevent the spread of these parasites.

Dr. Allan Paul, veterinary parasitologist at the University of Illinois College of Veterinary Medicine in Urbana, explains that two parasites found in pet poop, roundworms and hookworms, can infect humans through ingestion or skin contact. Both are very common in puppies and kittens.

Roundworms can be spread to puppies from their mother before they are born; dormant roundworm larvae in the mother's bloodstream can become activated during pregnancy and cross the placenta to infect the puppies. In fact, according to Dr. Paul, virtually 100 percent of puppies are born with roundworms. Unlike puppies, kittens do not acquire roundworms from their mother in utero, but nursing milk that contains roundworm larvae can infect them.

If left untreated, roundworms can migrate in the body to infect vital organs and cause permanent, even fatal, damage, so young animals are usually put on a deworming program at a few weeks of age.

Adult dogs and cats can ingest roundworm eggs or larvae from the environment, but don't usually get sick. Rather, the larvae remain throughout the body in the dormant form.

Hookworms are another parasite that can be acquired via mother's milk or through direct ingestion. Hookworm larvae can also be absorbed through the skin, causing skin lesions, and may travel through the body to infect the intestines. Once they infect the intestinal tract, they can suck large amounts of blood, causing anemia. Like roundworm infections, hookworm infections can be treated with deworming drugs.

If a pet's roundworm or hookworm infection goes untreated, not only can a puppy or kitten develop serious disease, but also the environment can become contaminated with eggs that are excreted with feces and pose a health risk for humans. Roundworm and hookworm infections are as serious for humans as they are for pets.

One female roundworm can lay up to 200,000 eggs a day. Dr. Paul explains that these eggs are very resilient, and the only way to effectively destroy them is with flame or steam. Indoor kennels can be steam cleaned to reduce contamination. Since chemicals cannot destroy the eggs, contaminated lawns can pose a challenge, especially since the eggs can survive in the soil for many years. Fortunately, roundworm eggs do not become infective until two to three weeks after leaving the body through feces and only mature to this infective state if environmental conditions are just right.

Hookworm eggs, however, become infective only two days after leaving the body, so they too can pose a contamination problem. Humans, like dogs and cats, can acquire roundworms via ingestion, and can contract hookworm infection through ingestion or skin contact. People at higher risk for infection by these parasites include children, especially those who may eat sand or dirt, and people who work with soil and sand that may be contaminated, such as landscapers and plumbers.

An effective way to prevent infection is keeping the environment clean. Picking up after your pet promptly when it defecates in public spaces, such as parks, and cleaning feces out of your yard or litterbox at least every other day can keep roundworm and hookworm eggs from reaching their infective stage. Keeping children's sandboxes covered when not in use can keep the sand clean and parasite free.

In areas where hookworms can be a problem, you can minimize your contact with contaminated soil or sand by wearing shoes and sitting on blanket when relaxing outdoors. Of course, washing hands thoroughly after working or playing outside and before eating can prevent ingestion and spread of parasites as well as other infectious agents like bacteria and viruses.

In addition to keeping the environment clean, Dr. Paul suggests some simple steps to keep your pet from acquiring active infections. Standard deworming drugs can decrease worms in a puppy or kitten and decrease shedding of eggs in feces by up to 100 percent. A veterinarian should examine a pet's stool sample every six to 12 months, when the pet gets its routine veterinary examination.

Monthly drugs, taken orally or applied topically, can prevent roundworm and hookworm infections, and some monthly heartworm treatments include these preventives. Keeping dogs in a fenced yard and cats indoors has numerous health benefits, since animals allowed to roam naturally run a higher risk of getting parasites and other infectious illness.

For more information about roundworms and hookworms, contact your local veterinarian or visit the Centers for Disease Control Web site about the connection between pet health and human health at http://www.cdc.gov/healthypets/.