4 Reasons You Might Get A Parasite

Despite traveling extensively, including to many developing countries (I've been to Africa more than 20 times), I've managed to get through most of my adventures without becoming seriously ill. But when I recently told my doctor that I had been white-water rafting in the Zambezi River in Zimbabwe, he looked alarmed. Apparently it's loaded with Giardia, a parasite that can make you pretty sick if you accidentally swallow water that's been contaminated with it. 

Fortunately, I was fine, but it got me thinking about parasites and the risks of getting one, both in the U.S. and abroad. How easy is it, and how dangerous are they, anyway? 

The answer, it turns out, is complicated. Just as there are many different viruses and bacteria that can cause everything from the common cold to a life-threatening infection, "there are so many different types of parasites that the level of concern depends on the specific scenario," says Brunilda Nazario, MD, a board-certified internist and endocrinologist based in New York City.

In other words, parasites can be merely annoying (like lice) to downright scary (like brain-eating amoeba). What they all have in common is that these organisms need a "host" to survive: A parasite either attaches to you or lives inside you and feeds off your body at your health's expense. 

You can catch a parasite just about anywhere, but certain scenarios majorly raise your risk. Here are 4 that should be on your radar. (Heal your whole body with Rodale's 12-day liver detox for total body health.)

You're visiting (or just got back from) a developing country.

"Parasitic infections are more common in rural or developing areas of Africa, Asia, and Latin America," says Nazario. These area are often home to malaria, a parasite that's transmitted to humans when they get bitten by mosquitoes that carry it. Of all parasitic infections, malaria causes the most deaths globally. 

Of course, this doesn't mean you should avoid traveling to places where malaria is found; you just have to be smart. Take antimalarial drugs before, during, and after your trip as a preventive measure, use insect repellant with DEET, sleep under a mosquito net or in an air-conditioned room, and wear long pants and long shirts at dawn and dusk. If you feel sick upon your return, make sure you tell your doctor about your travels so he can run the appropriate tests. 

You have a child in a daycare center or elementary school.

The parasite pediculosis (head lice) is easily spread among young children: Lice can jump from head to head, crawl along carpeting, and live in someone's hat or brush that your kid just borrowed. And once the little ones bring lice home, it's rarely long before the grownups in the house start scratching. 

While combing out nits can be a pain (and gross), head lice aren't dangerous, and medicated shampoo usually does a good job of killing off live lice. 

You have a cat.

Cats can spread the parasite toxoplasmosis, especially outdoor cats that might nibble on small rodents or birds. The cats pass the parasite through their fecal matter, and when you go to change the kitty litter you can become infected. Toxoplasmosis isn't always dangerous—many people have it and don't know it—but if your immune system isn't up to par, trouble could ensue. Ditto if you're pregnant: You can pass toxoplasmosis on to your fetus, and in rare cases it can result in eye and brain damage to the baby. 

The best way to avoid toxoplasmosis is to wash your hands after changing the litter before doing anything else (especially touching your face!). If you're pregnant, relegating litter-changing duties to your partner and keeping your cat indoors (so he's not eating the infected birds and rodents in the first place) are also smart moves. 

You consume contaminated food or water.

No one (we hope) would intentionally drink water that's been contaminated with raw sewage thanks to poor sanitation, eat fruits and vegetables that were washed in it, or order fish that swam in it. Still, it happens, and it can lead to catching parasites like Giardia or a tapeworm. 

When traveling, it pays to take note of any special warnings aimed at tourists, such as not to drink the tap water. If you do somehow get sick, would you know it? Maybe. If you accidentally eat food that's contaminated with bacteria, you'll probably end up with GI distress (think vomiting and diarrhea) that comes on rather abruptly. But parasitic intestinal infections tend to be insidious—symptoms come on slowly and gradually—plus they may or may not involve your digestive system, says Nazario. Skin lesions, confusion, and other issues are possible; it just depends on the type of parasite. 

Of course, anytime you notice strange symptoms, no matter what they are (or where you are), it makes sense to talk to your doctor. If your doctor suspects that you have a parasite, he may need to do a little digging to sort it out. "Diagnosis requires samples of various body fluids like blood, stool, and urine. For example, if a parasite lives in your intestinal tract, eggs or cysts may be seen in a stool sample under a microscope," says Nazario. "But occasionally a tissue biopsy is required of the lung, skin, or intestine." 

While most parasites can be treated with medication, prevention is always the best medicine. "Wash your hands with soap and water after using the toilet, changing a diaper, caring for someone that's sick, before eating, after picking up animal waste, and obviously when preparing food," says Nazario. "Avoid drinking from lakes and streams and swallowing water in swimming pools or water parks." And travelers to areas that have parasites in food and water should boil, cook, or peel anything they ingest.