THE HIDDEN DANGERS OF DIRTY WATER: A SWIMMER'S GUIDE TO INFECTIONS

We usually focus on strokes, equipment, and speed. But there is a scarier side to swimming: the microscopic dangers that lurk in the water.

According to the CDC, recreational water illnesses (RWIs) are a real risk in both man-made pools and natural bodies of water.

In this guide, writer and avid swimmer Marina Salsbury breaks down the most common infections you should know about, from the chlorine-resistant bugs in the pool to the parasites in the open water, and how to avoid them.

(Note: This article is not meant to scare you away from the sport, but to help you swim smart and safe!)

Dive Into: A Guide to Water Safety and Hygiene

• The Dangers Lurking in the Pool
• Hot Tub Hazards: Heat Doesn't Kill Everything
• The Dangers of the Open Water
• International Risks: Swimming Abroad
• The Takeaway: Use Common Sense
• Frequently Asked Questions

The Dangers Lurking in the Pool

Many swimmers assume that chlorinated pools are sterile environments. While chemicals do a great job, they aren't perfect.

1. Cryptosporidium ("Crypto") This parasite is the leading cause of pool-related diarrheal illness. Why? Because it has a tough outer shell that allows it to survive for days even in properly chlorinated water. If someone with Crypto has an accident in the pool, the germs can spread quickly.

2. Hepatitis A This virus can contaminate pools through raw sewage, which can occur after heavy rainstorms overwhelm local systems. While proper chlorine levels usually kill it, pool maintenance failures can leave swimmers exposed.

3. Swimmer's Ear (Otitis Externa) This is one of the most common infections. It happens when water stays in your ear canal for too long, creating a moist environment for bacteria to grow.

Hot Tub Hazards: Heat Doesn't Kill Everything

You might think the high heat of a jacuzzi kills bacteria, but hot water actually breaks down disinfectants like chlorine faster.

1. "Hot Tub Rash" (Pseudomonas) This bacteria thrives in warm water and causes a skin rash known as folliculitis. It can affect even healthy individuals.

2. The Amoeba Risk Free-living microscopic amoebas like Acanthamoeba can enter the body through the nose or eyes, causing severe infections. This is a particular risk for those who wear soft contact lenses in hot tubs.

The Dangers of the Open Water

Natural water sources like lakes, rivers, and oceans are not treated with chemicals, so you are swimming in a living ecosystem.

1. Giardia A notorious infection among hikers, Giardia is a parasite found in water contaminated with feces. Swallowing contaminated water can lead to severe abdominal cramps and weight loss.

2. Leptospirosis This bacterial disease is often transferred into water via waste from livestock or wild animals. It is a risk for those swimming in rivers or lakes near farms or agricultural areas.

3. E. Coli This bacteria is a major cause of illness and is spread through contaminated water. It serves as a reminder for the golden rule of open water swimming: try not to swallow the water.

4. Swimmer's Itch (Cercarial Dermatitis) This is one of the most common annoyances for lake swimmers. It is an allergic reaction to microscopic parasites released by snails. If they burrow into your skin, they cause red, itchy bumps or blisters. While the parasite cannot survive in humans and is not dangerous, the itching is intense. Tip: Towel off vigorously immediately after leaving the water to prevent them from burrowing.

International Risks: Swimming Abroad

If you are traveling, especially to tropical or developing nations, extra precautions are needed.

1. Schistosomiasis This disease is caused by parasitic worms released by freshwater snails. It thrives in standing water in tropical countries and can lead to serious long-term health problems.

2. Dracunculiasis (Guinea Worm) While rare today thanks to eradication efforts, this parasitic worm enters the body through drinking contaminated water. It is primarily found in a few sub-Saharan African nations.

The Takeaway: Use Common Sense

This list might sound scary, but the reality is that millions of people swim safely every day. The key is to use common sense.

• Don't swallow the water.
• Avoid swimming if you are sick (especially with diarrhea).
• Check the conditions. If the water looks murky, smells bad, or you see dead fish/animals, stay out.
• Shower before and after you swim.

As the saying goes, what doesn't kill you makes you stronger. So get out there, appreciate every stroke, and enjoy the water, just be smart about it!