Preventing Illness and Injury
Giardia

Background

Giardia is a parasite. It is ubiquitous in the wilderness. The EPA says 80% of all water in the wild contains this protozoan, typically in streams and lakes, but even in the snow you might melt. Giardia protozoa spend part of their life cycle in the intestines of mammals. Think of all the mammals that poop in the water, directly or indirectly; the marmot on the boulder surrounded by snow, the pica scurrying around the rocks with a stream flowing under, the beaver that fouls the stream, the horse or mule that stops at each stream crossing to relieve, the infected Homo Sapien who did not wash his/her hands before preparing food.

Symptoms & Treatment

Foul smelling diarrhea, fatigue, bloating, cramps, gas and nausea - usually a week or two after the organism is swallowed and starts growing in some corner or bend of your intestine. This can continue for up to four months. Yet many people are infected but develop no symptoms, or get over the attack without treatment. Yet others develop a chronic infection. Giardia is tricky to diagnose through lab examination of stool samples since giardia cysts are excreted only periodically. So physicians not familiar with the disease sometimes miss the diagnosis. Treatment is effective with prescription anti-parasitic drugs, but there can be unpleasant side effects.

Prevention

You could be a carrier and not know it; so wash your hands thoroughly after toileting. For day hikes, carry sufficient water from a domestic supply rather than counting on "wild" water.

There are three methods of treating wild water: boiling, filtering and treating with chemicals.

Boiling: Bring water to a full boil, then let cool. It is not necessary to boil the water for any specified time beyond the initial full boil. This method is effective in camp but impractical on the trail and it uses fuel.

Filter: Portable "backpacker" filters are effective. They cost upwards of $70. Some are bulky. The filtering process is relatively slow.

Chemical Treatment: Two commonly used chemicals are iodine and chlorine. Both are cheap and commonly available. Iodine comes in pill form ("Aqua Pura") while chlorine comes in liquid or crystal form. These are effective IF the directions are followed carefully. In particular they take time in the canteen or water bottle to do their thing and the amount of time varies with temperature. You are not protected if you add the chemical and gulp. Some people are bothered by the taste but this can be masked with Gatorade or lemonade.