Do You Have Parasites?

Five signs you may have these bad bugs, and how to get rid of them.

- By Lisa Turner

You probably assume that parasites are a problem only if you’ve traveled to remote regions with iffy sanitation. But they’re way more common than you might think. Millions of Americans have parasites, and some types infect as much as five percent of the U.S. population. Here’s what you need to know about those bad bugs—and how to banish them, for good.

Who’s at risk?

“Parasite” is a broad term that describes any organism that lives and feeds off another organism, including lice, giardia, and even mosquitoes. Intestinal parasites—including worms (known as “helminths,” usually visible without a microscope) and protozoa (microscopic, single-celled organisms)—specifically reside in the gut. Pinworms are the most common parasite in the U.S., living primarily in the large intestines. Giardia is the second-most frequent domestic parasite. When it’s swallowed, it makes its way through the digestive tract, splitting into two hungry microorganisms that attach to the walls of the small intestines. Other parasites, such as hookworm and whipworm, are less common in the U.S. And while you’ll hear plenty of horror stories about tapeworms—flat, segmented beasts that can grow as long as 50 feet—they’re relatively rare. You’re probably at risk only if you’ve traveled to a developing nation or work closely with livestock.