According to Richard Pearson, M.D., Professor of Medicine and Pathology at the University of Virginia School of Medicine, hundreds of millions of people throughout the world are infected with nematodes. Nematodes are roundworms. Most of them are small and do not seem to matter very much. But there are some nematodes that most definitely matter, because they can cause disease. And while you can become infected by them in more than one way, many of them either mate, hatch their eggs or mature in your intestines.
Ascaris Lumbricoides
Ascaris lumbricoide is a very large roundworm. As a matter of fact, the adults are the largest roundworms found in the intestines, for they grow as long as 12 inches and lay thousands of eggs every day. You become infected if you accidentally eat some of their eggs, which found their way to soil where they were released via an infected person's bowel movements. The eggs will hatch in your small intestines, but then go through its wall and into your bloodstream; from there, the worms enter your lungs. But they can be coughed out of the lungs, swallowed, and return to your intestines. Most of the time, the Ascaris do not cause any symptoms. They can cause pneumonia, and if there are a large number of them in your intestines, they can give you abdominal pain.
Strongyloides Stercoralis
Strongyloides is a small roundworm. It can break through your skin, get into your bloodstream, travel to your lungs, migrate upward, get swallowed and finally reach your intestines. This roundworm will then mature in your intestines, hatching eggs there. If you become infected with Strongyloides, you will continually be reinfected because the worm's larvae will exit through your bowel movements, but then break through your skin again. The only way to stop this continuous cycle is to be treated. Like Ascaris, most people with a Strongyloides infection do not have any symptoms. It can cause a lung infection, watery or bloody diarrhea, and an infection in your bloodstream.
Trichinella Spiralis
If you eat pork that has not been thoroughly cooked and it has this worm's larvae in its muscle, you will get infected with Trichinella. Actually, Trichinella will infect any animal that eats meat, but it usually infects pigs. If you become infected, the larvae will mature in your small intestines and the worms may make thousands of larvae while there. Larvae will then go through the wall of your intestines, invade your bloodstream, enter your muscle and form cysts. If you have only eaten a few larvae, then your symptoms will be mild. Trichinella can cause muscle pain and fever (see Resources).
Trichuris Trichiura
Trichuris trichiura, a roundworm, is referred to as a whipworm because it looks like a whip. If you eat this worm's eggs, they will hatch in your small intestines. The worms will then travel to your large intestines to mate. They produce thousands of eggs, which leave your body in your bowel movements. Most people are asymptomatic, but some have diarrhea.
Enterobius Vermicularis
Enterobius Vermicularis is a roundworm referred to as a pinworm. It is the most common parasitic worm infection in America, mainly infecting small children. After you eat its eggs, they will hatch and like Trichuris, the worms mate in your intestines. The female worms crawl out at night and lay eggs right outside your anus. The eggs are infective for over a week, even if they get on furniture and toys. Thus, Enterobius spreads quite easily. Most people are asymptomatic or just have itching around their anus (see Resources).
Necator Americanus
The Necator roundworm is a hookworm. Just like Strongyloides, the larvae will break through your skin, travel through your blood to your lungs, migrate upward where they can be swallowed, and finally reach your intestines. They mature there, feeding off of the blood in your intestinal capillaries, producing thousands of eggs every day. The eggs are released in your bowel movements, and the cycle can begin again. You can become anemic from the worms feeding off your intestinal capillaries. You also can develop pneumonia as a result of these worms.
References
- Foundations of Parasitology; Larry Roberts, John Janovy, Jr.; 1996
- The Merck Manual: Nematodes (Roundworms)
- WebPath: Ascaris lumbricoides, gross
