Legionella risk assessments tend to focus on the indoor water supply in a property, since that is where the majority of the water outlets are to be found, but it’s worth bearing in mind that there are risks in the garden too. Just last week a case of a 63-year-old man hit the headlines after he sadly died from Legionnaires’ disease and his garden hose was traced as the source. With temperatures rocketing and many people spending time in the garden, this week we look at the Legionella hot spots in the great outdoors.

Legionella likes it hot

The tragic case of Stephen Clements from Norfolk is a clear illustration of how Legionella can flourish and cause harm if the right environmental conditions are met. Mr Clements used his garden hose to clean his patio and then left the hosepipe trailed across the lawn in the sunshine, still containing some water. We know that Legionella bacteria occur naturally in water so the key is to ensure that conditions are controlled to stop it from growing and inflicting illness.

What does bacteria need to grow? Firstly, the correct temperature. In the case of Legionella, this is between the temperatures of 20°C and 40°C, i.e. a range which directly correlates to the warmth of British sunshine. As Mr Clements’s hosepipe lay in the sunshine, containing water which wasn’t flowing, it heated up to the perfect temperature for encouraging bacterial growth.

Our advice is to always put away your garden hose after use and try to store it out of direct sunlight. By coiling it up you should be able to expel most of the water before you store it too.

Making a splash

The next step in the process was critical to Mr Clements’s infection as the bacteria was transferred from the water lying in the hose to a form where he could breathe it in, thus allowing it to take hold in his lungs. How did this occur? He used a spray attachment and a broom to scrub the garden terrace clean. By creating a water spray which was dispersed in the air all around him as he worked, the bacteria was able to enter his airways in vapour form.

If you are using any kind of spray action – whether in a sprinkler, a rose attachment on the hose or even the good old thumb over the end – first flush your hosepipe at a distance. If any bacteria are lurking inside the hose, by putting the hose in the corner of the garden or away from people and turning the tap on full for a couple of minutes, you will expel the nasties without breathing them in.

Health problems

The third factor which had a strong bearing on this case was the fact that Mr Clements had a heart condition. While his wife describes him as well and active, his underlying health condition meant that he was more susceptible to Legionnaires’ disease. Anyone with a compromised immune system or long term conditions such as heart or lung disease, diabetes, asthma, are at greater risk of falling ill following exposure to Legionella bacteria. Similarly, smokers and heavy drinkers as well as those over 45 fall into a higher risk category.

Anyone who is in one of these high risk groups should take suitable precautions, either by getting a less susceptible family member or friend to help out, or by using a face mask. If you use a hosepipe regularly, consider disinfecting it from time to time too, to eliminate bacteria.

Spreading the word

The story of Mr Clements’s untimely death is indeed a sad one, but it is also fairly typical of how Legionnaires’ disease can strike suddenly and arise from a seemingly innocuous everyday activity. It’s good to see his widow working hard to raise awareness of the risks and we very much hope that the national publicity which has been generated will help spread the word about prevention and control of Legionella.