Swimming in fresh water while travelling

Tell us about any swimming you plan during your travel consultation. Rafting, canyoning or kayaking in the rainy season? A preventive antibiotic may be discussed. Take closed shoes, waterproof plasters and, for boat trips, a life jacket.

Bilharzia (or schistosomiasis) is caused by a small worm. Small freshwater snails release its larvae, which pass through the skin while you swim, even without a wound. Once adult, the worms live for years in the veins of the intestine or bladder. Their eggs slowly damage the organs, often without any sign for months.

More than 9 out of 10 people with the disease live in Africa, including Madagascar. There are also risk areas:

• in the Middle East, especially in the Arabian Peninsula;
• in Asia: China, the Philippines, Indonesia, the Mekong in Cambodia and Laos;
• in South America: Brazil, Venezuela, Suriname;
• on a few Caribbean islands (very low risk);
• in Corsica, where a few people have been infected in a river since the early 2010s.

Do not swim or walk in fresh water, especially near the banks where the snails live. To wash with lake or river water, heat it to 50 °C for 5 minutes. Or let it stand for 24 hours.

This bacterium comes from the urine of animals, especially rats, and survives in water and mud. It enters through a small wound, the eyes or the mouth. It is found in all tropical regions, and rarely in Switzerland, and is mainly a concern after heavy rain.

Avoid floodwater and mud, and wear closed shoes. Do not swallow the water, and wash any wound that has touched it with soap. There is no vaccine. If treated early with antibiotics, it usually heals: see a doctor quickly if you have a fever.

Drowning is a major cause of death while travelling. Alcohol is involved in 3 out of 4 deaths among teenagers and adults. No alcohol, never alone in unfamiliar water, feet first. Keep young children within arm's reach.

A very rare amoeba in warm fresh water enters through the nose and attacks the brain. In warm fresh water, do not dive and wear a nose clip.

• "A fast-flowing river is safe." False. The risk is lower than in still water or a pond, but it also exists in a fast-flowing river.
• "A medicine taken just after swimming prevents the disease." False. No medicine has been shown to have this effect.

In Switzerland, emergencies: 144. Abroad: the local emergency number.

1. Fever during the trip or after your return: see a doctor the same day. Say where you have been in fresh water.
2. Yellow skin or eyes, passing little urine, bleeding, difficulty breathing, severe headache, stiff neck or confusion: go to the emergency department immediately.
3. Someone is drowning: do not go into the water yourself. Hold out a pole or a rope to them, then call for help.
4. Itchy spots after swimming: not serious in themselves. Have the check-up at 3 months.

In doubt, but not a life-threatening emergency? Message us on WhatsApp.

The test looks for antibodies against the worm, which take weeks to appear: done too early, it can falsely reassure you. Have it even if you feel well. If it is positive, tablets kill the worms and prevent complications.

Also see a doctor if you have fever, a cough, stomach pain or blood in your urine, even later on.