Parasitic worms are enterprising creatures that force their way into the intestinal tracts of unsuspecting human hosts. Worm eggs can be transferred from a blade of grass to the tips of your children's fingers; or they can be swallowed at a 4-star restaurant.
The human intestinal tract is the perfect accommodation for these freeloaders. Worms can gorge themselves in the human gut for months or years before they are detected, causing everything from a poor-night's sleep to life-threatening intestinal blockages and malnutrition.
There are hundreds of types of worms (helminths) that infect humans worldwide. They come in all shapes and sizes - flat, round, hooked and barbed.
Although intestinal worm infections are more common in countries where people endure poor sewage disposal, water treatment and food sanitation, adults and children living in the United States are very much at risk, particularly if they travel abroad.
Humans can become infected if they swallow eggs, larvae, cysts, or adult worms living in food, drink, soil and feces.
Here are some of the parasites wiggling into the lives of people living in the US.
Ascariasis caused by Ascaris lumbricoides, a type of roundworm (nematode), is the most common parasitic worm infection worldwide. As soon as the eggs are swallowed, they begin to develop. The larvae penetrate the wall of the small intestines and wriggle into the bloodstream where they travel to the lungs. When they are more mature they crawl up from the lungs to the bronchial tubes and throat. The host coughs and swallows the worm-laden mucus. By the time the larvae reach the small intestines they are adult worms.
The full life-cycle takes 2 to 3 months. Each adult worm can live in the gut for up to 2 years and pass 200,000 eggs into feces every day. People acquire the infection when eggs in feces, soil, food and water are ingested.
Symptoms of Ascaris Roundworm
- Shortness of breath
- Cough (sometimes containing worms)
- Loss of appetite
- Abdominal pain or distention
- Intestinal obstruction
- Eggs or worms in stool