A refreshing dip in a lake or river can feel like the perfect way to cool off on your travels. But in certain parts of the world, that swim could come with a hidden danger: schistosomiasis, also known as bilharzia. This parasitic infection is common across much of Africa, parts of South America, Asia, and the Middle East — and travellers are often caught off guard by the risk.

What Is Schistosomiasis (Bilharzia)?

Schistosomiasis is caused by parasitic worms that live in freshwater snails. When the larvae are released into the water, they can penetrate human skin. Once inside the body, the parasites mature and can cause long-term damage to organs including the bladder, kidneys, liver, and intestines.

Globally, more than 200 million people are affected each year. While it is treatable with the medication praziquantel, the key is prevention and early detection.

Where Is the Risk Highest?

For travellers, some of the most popular but risky destinations include:

• Lake Malawi – especially the lower regions. Despite its beauty, this lake is one of the most well-documented schistosomiasis hotspots.
• Lake Volta, Ghana – the largest man-made lake in the world, with high infection rates in surrounding communities.
• Other regions – parts of Tanzania, Zambia, Uganda, Senegal, and Egypt’s Nile Valley also carry significant risk. Outside Africa, schistosomiasis is found in areas of Brazil, the Philippines, and China’s Yangtze River basin.

How Travellers Get Infected

The risk comes from freshwater exposure. Swimming, paddling, diving, or even wading in contaminated water can be enough. Washing clothes or fishing in lakes and rivers can also carry a risk.

It’s worth stressing that chlorinated swimming pools and the sea are safe. The problem lies specifically with lakes, rivers, and other untreated freshwater sources in endemic regions.

Symptoms to Watch For

Schistosomiasis doesn’t always make itself known straight away. Early signs can include:

• A rash or itchy skin shortly after exposure
• Fever, chills, cough, or muscle aches within weeks
• Blood in urine or stool in more established infections

Longer term, untreated schistosomiasis can lead to serious complications such as liver damage, kidney failure, or bladder cancer. Because symptoms can be subtle or delayed, it’s vital to seek medical advice if you’ve had possible exposure.

How to Protect Yourself Abroad

The best prevention is also the simplest: avoid swimming in freshwater in endemic areas, even if locals or other travellers are doing so.

• Stick to well-maintained hotel swimming pools or the ocean.
• Use safe, treated water for bathing or washing.
• If you suspect accidental exposure, don’t panic — but do arrange a medical check-up when you return.
• Avoid showering in water taken directly from fresh water

There is no preventive tablet or vaccine, but praziquantel treatment is highly effective once infection is confirmed.

When to Seek Medical Advice

If you’ve swum or waded in freshwater in regions such as Lake Malawi or Lake Volta, it’s sensible to mention it at your next health check-up. Even without symptoms, testing is recommended, as early treatment prevents long-term damage.

Travel Safe with Expert Advice

Schistosomiasis is one of those travel risks that many people never hear about until it’s too late. But with the right awareness, it’s entirely preventable. Before you travel, talk to a TMB travel health expert. Our team can advise you on region-specific risks and make sure you have the information and protection you need for a safe, healthy journey.