- August 26, 2025
- Kevin Kholer
Summer Safety: Preventing Waterborne Protozoan Illnesses
Stay Alert During Late Summer
Late summer is a high-risk season for exposure to waterborne protozoa—microscopic organisms that can cause serious intestinal illness. Found in water contaminated by human or animal feces, these parasites spread easily, especially in outdoor and recreational settings. Illnesses such as giardiasis and cryptosporidiosis are common worldwide, and prevention is key.
Giardiasis: The Basics
Known as “beaver fever” in North America, giardiasis is caused by the parasite Giardia. Many wild and domestic animals carry it, and infections spike in late summer and fall. Giardia can survive for long periods in cold water, making natural sources a common risk.
Symptoms typically begin 7–10 days after exposure and may include:
- Diarrhea
- Abdominal cramps
- Gas and bloating
- Pale, greasy stools
- Nausea
- Weight loss and fatigue
Some people show no symptoms, while prolonged cases can lead to more serious conditions like reactive arthritis or intestinal damage.
Cryptosporidiosis: Another Risk
Cryptosporidium, spread through animal or human feces, can contaminate water sources, especially where water treatment is insufficient. These protozoa form hardy spores that survive harsh conditions.
Symptoms are similar to giardiasis and may also include mild fever. While the illness usually resolves without treatment, people with weakened immune systems are at higher risk for complications.
How Exposure Happens
You can ingest these parasites by:
- Drinking untreated or improperly treated water (streams, lakes, shallow wells)
- Swallowing contaminated water while swimming in natural or recreational waters
- Eating contaminated food
- Having contact with feces from infected individuals
- Drinking from compromised municipal or private water systems
Prevention Tips
- Avoid untreated water from natural sources such as springs, rivers, lakes, and shallow wells.
- Wash your hands frequently, especially after using the toilet and before eating.
- Boil water or use filters rated to remove protozoa, as advised by your health authority.
- Chlorine may not be enough—consult your local health authority when using chemical disinfectants.
- Avoid swallowing water when swimming, especially in natural water bodies or public pools.
- Steer clear of areas with runoff or pollution, and check local advisories for water safety.
See a healthcare provider promptly if you suspect a parasitic infection.
Workplace Considerations
If employees are working near water sources, it’s important to:
- Conduct hazard assessments for potential protozoa exposure
- Educate workers on risks and prevention strategies
- Implement control measures to reduce exposure
Stay safe this summer—practice good water hygiene whether you’re at work, home, or on vacation!