What is it? And What Can We Do About it?
This article was obtained from a brochure by Jefferson County Health Department and by conversation with Barbara Martens - RN/Communicable Disease Control Coordinator and Mindi Arris - Environmental Health Specialist who are both with Jefferson County.
Camping and Hiking in the High Country
High-country camping and hiking are popular activities in Colorado. Scenic trails and quiet woodlands cut by sparkling streams are a delight to the senses. But hidden within the seemingly clear waters of most mountain streams are microscopic creatures - giardia - which may cause serious illness if ingested. To protect yourself, know the facts and take proper precautions.
Have you had diarrhea, cramps, nausea, vomiting or fatigue; symptoms which vanish and then reoccur at cyclic intervals? You may have Giardia.
Giardiasis is a protozoal infection of the small intestine. Protozoans are microscopic single cell organisms with complex life cycles. The organisms Giardia lamblia, exists in two stages: the active trophozoite (adult stage) and the dormant cyst. The life cycle is started by ingestion of cysts. In the small intestine, the cysts are transformed to the adult stage. Reproduction is by simple fission. As trophozoite pass through the intestinal tract encystations (changes from the adult form to the cyst form) occurs. The cysts are released to the environment through fecal wastes. The cycle is repeated if an individual ingests the cysts, either rthrough contaminated water or fecal-oral contact (hand to mouth transmission). To prevent fecal-oral contact, the following is suggested.
Factors Common to Outbreaks
1. Chlorine not effective - a complicated combination of C1 2 residual, pH, time and temperature is necessary to kill the cysts, and is not considered practical or feasible.
2. The effects of other disinfectants, such as ozone and UV radiation are not well known.
3. Filtration is effective provided the filter pore size is no larger than 1.0 micron. This type of filtration should be implemented for surface sources, infiltration galleries or shallow springs. A larger pore size filter should be used ahead of the finer filter to prevent premature plugging.
4. Boiling water for 10 minutes destroys the cysts.
5. For large water treatment plants, adequate control can be acheieved through a combination of filtration and chemical per-treatment.
Common Misconceptions about Giardiasis
"Water in streams is purified after flowing for ½
mile". Giardia cysts are stable in water and do not die off
down stream. All mountain streams should be presumed to be contaminated
by Giardia cysts.
more information, contact the Jefferson
County Health Department at 303-232-6301.