Worms That Live in Humans

There is a scientific phenomenon known as "parasitism," in which one being--the parasite--latches onto a designated host and leeches benefits at the host's expense. One such parasite is the worm. While the common earthworm is of no harm to anyone, the parasitic worm may live off cats, dogs or even humans. At worst, the condition can be lethal.

Types

• Hundreds of different parasitic wormscan live in a human, but the most common types are roundworms, hookworms, heartworms, whipworms and pinworms. Roundworms resemble an earthworm and can lay up to 200,000 eggs per day. Hookworm larvae penetrate the skin, and when the young worms are grown they use their teeth to burrow through the intestinal wall and feed on the host's blood. Heartworms reside in a chamber of the heart, whipworms infect the large intestine and pinworms tend to infect children.

Symptoms

• A person suffering from worm infection may experience constipation, diarrhea, a bloated stomach or any number of other digestive disorders. If someone eats plenty of food and still doesn't feel sated, or eats healthy but still looks malnourished, a worm may be leeching nutrients off him. Worm infection can also lead to skin rash and other reaction-specific health problems. Heartworms naturally cause problems with the heart, but those are rare in humans.

Significance

• Parasitic worms are harmful to humans. They cause a variety of health problems that lead to other diseases and, in some cases, death. According to the Worms and Parasites website, more than 1 billion people in the world are affected by roundworms alone.

Treatments

• Treatments vary depending on the type of worm. Typically some sort of medicine is ingested or injected, something lethal to the worm but not to the host. This works on heartworms as well: small doses of arsenic-based compound are administered into the blood, eventually reaching the heart and killing the worm. However, medicinal treatment is not always enough. In some cases surgery will be required. In others, the worms may have triggered a secondary illness, such as autoimmune disease, which will need to be treated until the worms have been removed.

Prevention

• The key to preventing a worm infection is clean living. Wash all the pots and pans after they are used, and make sure the meat has been cooked all the way before eating it. Food should always be washed at least once, and the house should be regularly swept and kept free of mosquitoes. If there are any pets, they should be taken in regularly for a check-up. It isn't common, but a human can contract a parasitic worm from an infected dog or cat.