Dog Worms & Human Infection

According to vetinfo.com, five types of worms (internal parasites) infect dogs--heartworms, roundworms, tapeworms, hookworms and whipworms. Three of these five--roundworms, hookworms and tapeworms--classify as zoonotic, which means transmission possibility from animals to humans. The presence of dogs in households increases risks for human infection, especially children. Early pet detection and treatment will prevent environmental contamination and parasitic transmission to humans.

  1. Dog Roundworms

    • Dogs naturally host roundworms as intestinal parasites. Puppies commonly acquire roundworms from their infected mothers before birth or soon afterward. Also, infection occurs by their eating infected animals or soil. Roundworm eggs live in the soil for many years. When the puppy ingests the eggs, they hatch in the intestines, where they grow to adulthood and produce more eggs.

    Human Roundworms

    • Humans do not naturally host roundworms. Transmission to humans usually occurs through infected soil in lawns. Eggs from the soil stick to hands and clothing, transfers to the mouth and infects the individual. The severity of infection depends on how many eggs are ingested. The ingested eggs hatch and larvae can migrate throughout the body, damaging tissue, especially eyes. Blindness occurs when larvae migrate into the eye.

    Dog Hookworms

    • Like roundworm, hookworms live in dog intestines. This small thin worm hooks on to the intestine and sucks blood. Hookworms affect dogs of any age and infect puppies from their mothers. Non-maternal infection occurs by ingestion or larval skin penetration. Infected animals experience bloody stools, anemia, weight loss and depression. Hookworm infestations may kill puppies before detection.

    Human Hookworms

    • Humans contract hookworms by ingestion of larvae or direct penetration of skin. Simply walking on infected sand or soil infects humans. After penetrating the skin, larvae migrate under the skin and sometimes into other tissues. If not treated, the migrations may continue for weeks or months. Ingestion leads to intestinal worms, which causes bloody stools, abdominal pain and diarrhea.

    Tapeworms

    • Dogs cannot transmit tapeworms directly to humans. Both humans and dogs acquire tapeworm infections by accidentally ingesting fleas. Rodents, frequent prey of dogs, retain fleas infected with tapeworm larvae. After infection, long, flat tape-like worms inhabit the intestines. Sometimes worm segments break into the stool and appear as white specks. Tapeworms rarely cause serious symptoms. However, the parasite causes weight loss and anal itching.

    Prevention and Treatment

    • Focusing on good personal hygiene and healthy pet ownership prevents internal parasite infection. Hands need washing after working or playing in soil and dog feces need regular removal from the lawn. Also, wearing shoes inhibits egg and larvae contact. As soon as possible, new family pets should visit the veterinarian for deworming. Anthelmintics (dewormers) treat both dog and human worm infections. Monthly drug treatment prevents further dog and environmental infections. All treatments require either a veterinarian or a medical doctor.