January is peak season for booking holidays and – predictably – there’s even a special term for it: Sunshine Saturday. Apparently last Saturday, 7th January, the major tour operators were expecting over 1m holiday enquiries as people start to plan their summer holiday to take their mind off the post-Christmas slump. When you work in water hygiene and Legionella control however, foreign travel doesn’t just make you think of sandy beaches and sundowners as it’s also a significant source of Legionnaires’ disease.

When Public Health England, the body responsible for monitoring and recording cases of Legionnaires’ disease, tracks diagnosis rates it assigns each case a ‘likely exposure category’: community, nosocomial and travel abroad. In 2015 travel abroad was linked to 46% of Legionnaires’ cases in the UK, with countries across Europe, Asia and the Americas featuring on the table of source nations. Thailand and the United Arab Emirates topped the league, with Bulgaria and Italy not far behind, so it’s clear that this is not the preserve of poor or third world countries, but a democratic disease happy to thrive anywhere it finds little resistance.

So why is travel a risk factor for Legionnaires’ disease? One of the main issues is holiday accommodation, particularly hotels and apartment blocks where there is likely to be air conditioning, cooling towers and a large and complex plumbing system. The very first outbreak of Legionnaires’ disease occurred in a hotel and - after a lengthy investigation - it was found to have originated in the cooling tower of the hotel’s air conditioning system where Legionella bacteria was flourishing. Air conditioning systems are the perfect delivery mechanism for a waterborne bacteria which is breathed in via fine droplets in the air.

In other sorts of holiday accommodation e.g. mobile homes or caravans, boats, villas and even AirBnB properties, there may also be an issue of stagnant water. Where water is stored in a tank and is not used or flushed through frequently, Legionella bacteria can take hold. Temperature control is another problem, so where a tank in a mobile home or boat may be exposed to fluctuating outside temperatures and potentially quite warm weather, the water in the tank will heat up and create the perfect environment for bacteria to grow.

Cruise ships are another captive environment where, if proper Legionella control isn’t in place, disease can quickly spread via air conditioning and showers and infect large numbers of people. Swimming pools and Jacuzzis are also potential hazards if the water and filters are not properly cleaned and regulated.

An additional factor in foreign travel is the potential for less stringent Legionella control. Here in the UK we have some fairly rigorous legislation in place and a strong culture of health and safety, whereas in many other cultures and countries this is not necessarily the case. The United States still suffers from repeated outbreaks of Legionnaires’ disease, despite being arguably one of the most developed and technologically advanced nations on Earth.

While we don’t want to put a damper on the excitement of booking a holiday, it’s worth bearing in mind the health and hygiene record of your intended destination and chosen accommodation, especially if you’re in a higher risk group (over 50, a smoker or suffering from a compromised immune system).

And lastly, if you’re in charge of any holiday accommodation in the UK or own a boat or caravan, make sure you have proper Legionella controls in place (search our blog for advice).