Giardia is an ugly parasite you can easily bring home from a beautiful backpacking trip. It causes the disgusting (but generally not dangerous) intestinal disease giardiasis. You may have diarrhea for two to six weeks, or more, and you'll sincerely wish you'd been more careful.

You get giardiasis by swallowing the tiny cysts that enclose the giardia parasites. You may eat something that is contaminated. Or you may swallow water while rafting or sailing. Rarely, cysts lurk in public swimming pools, or at public water parks. In the right circumstances, they can even live in hot tubs and Jacuzzis.

To avoid giardiasis, avoid swallowing water that isn't positively safe. Nobody should drink from a clear mountain pool. There's no way of knowing what may have happened upstream, or yesterday. Travelers should avoid ice and unpurified water in locales with water treatment and sanitation systems they're not sure about. Bottled water is available almost everywhere now, so don't even brush your teeth with water you don't trust. Avoid uncooked or undercooked food, because thorough cooking kills the parasite. Especially avoid unpeeled or unwashed raw fruit or vegetables. When you wash food, be sure to use pure water.

To purify water, you can boil it for at least one minute, or use a filter that is NSF rated for cyst removal. It is possible to purify water using chlorine or iodine, using products found at camping stores, or even with laundry bleach. If you use either of these methods, follow label directions exactly.

Sometimes, giardiasis is obvious. The infected suffer with diarrhea, gas, greasy stools, cramp, upset stomach and nausea. There may even be weight-loss and dehydration. Other people may get giardiasis and not even know it. Then the disease has a better chance to spread.

Children often pick up giardiasis at day care, and can bring it home to their parents. Day care workers are also prone to giardiasis. Others at risk of the disease are people who get their water from shallow wells, which may be contaminated by runoff containing animal feces. Animals that may carry giardia parasites in their intestines include cattle, deer, beavers, cats, dogs, and people.

If you have giardiasis, you'll want to avoid spreading it. You should wash your hands thoroughly after using the bathroom, and before handling food. Naturally, you'll want to clean and sanitize your home. You shouldn't swim or wade until two weeks after the diarrhea stops. Meanwhile, rest, and stay hydrated.

A doctor can diagnoses giardiasis with stool samples. She may treat it with one of a variety of drugs. The doctor may choose to let what she considers a mild case run its course, partly because drugs have side effects. In the case of some treatments for giardiasis, the side effects may be especially unpleasant if the patient drinks alcohol.

Giardia is by no means the worst parasite in the world. Malaria is caused by a parasite. The heat-loving amoeba Naegleria fowleri enters the human body through the nose, and attacks the brain. It's found in warm lakes, hot springs, and dirty swimming pools. Fortunately, it is very rare, though almost uniformly fatal. If you are careless or unlucky and contract giardiasis, try to remind yourself that it could have been much much worse.

http://www.cdc.gov/ncidod/dpd/ parasites/Giardiasis/factsht_g iardia.htm
http://www.cdc.gov/healthyswim ming/
http://en.wikipedia.org/wiki/M etronidazole
http://www.msnbc.msn.com/id/21 034344/

Learn more about this author, Janet Grischy.
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