Whenever he returns from holiday, even before he’s unpacked his bags, a doctor runs a shower for 20 minutes to protect against a deadly disease.
Dr Tom Makin heads straight to the bathroom, turns on the shower, before running out again and repeating the ritual.
‘I cover my nose and mouth with one hand and turn on the shower with the other,’ he says.
‘After 20 minutes or so, I’ll turn the shower off and then I won’t go back into the bathroom for at least another 20 minutes.’
The ritual has nothing to do with superstition or obsessive behaviour, but is instead designed to protect Dr Makin and his family, inhaling potentially lethal bacteria called legionella that thrive in the stagnant water which collects in domestic shower heads when they are unused for anything more than a few days.
Although some may think it as over-cautious behaviour, without such preventive action, contaminated droplets of water could be inhaled into the lungs where they can cause legionnaire’s disease, a condition which triggers potentially life-threatening pneumonia and organ failure.
Few are as well placed than Dr Makin to know the dangers of legionnaire’s infection, a microbiologist from Cheshire who has spent nearly 30 years studying outbreaks.
He warns that the summer is the peak period for legionnaire’s infection risk due to hotter weather.
The bug thrives in stagnant water above 20C and below 45C – inside shower heads, water butts, pipes, and even in your garden hose or sprinkler system.
However it is not just bathing habits that can cause infection.
Something as simple as gardeners turning on their sprinklers for the first time in many months to perk up dry lawns are just as much at risk.
Most at risk are smokers, those with weakened immune systems due to existing health problems such as diabetes or cancer, and the elderly.
But the bug can affect healthy people too, earlier this month, 14 people fell ill after an outbreak linked to a hot tub at a health spa in Bournemouth.
‘We are seeing longer, hotter summers and that’s going to encourage the bugs to grow,’ says Dr Makin.
He added: ‘If you’ve not used the shower for more than three or four days, run it – with both hot and cold taps turned on gently – for 20 minutes.
‘If you have a flexible hose, place the shower head directly over the plughole – that way it doesn’t generate airborne droplets.
‘If not, shut the door behind you and don’t go back in for at least 20 minutes, or until all the airborne water droplets have dispersed.’
Legionnaires’ disease is a lung infection you can catch by inhaling droplets of water from things like air conditioning or hot tubs. It’s uncommon but can be very serious.
You can catch it from things like:
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