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Giardiasis

What is giardiasis?

Giardiasis is a waterborne intestinal illness caused by the microscopic parasite Giardia lamblia, commonly contracted by hikers and campers who drink untreated water from streams, lakes, or springs. The infection causes severe diarrhea, stomach cramps, nausea, and dehydration that can last for weeks if untreated. This is why outdoor enthusiasts must always purify, filter, or boil water from natural sources before drinking, even in seemingly pristine wilderness areas. Giardiasis is one of the most common reasons backpackers and hikers become seriously ill on multi-day trips.