Windscreen spray Legionnaires' risk

Car windscreen sprays may be behind 20 per cent of Legionnaires' disease in England and Wales, new research has found.

The potentially deadly bacterium can be found in stagnant water and is usually spread to people by contaminated water droplets in the air. Once inhaled, the bacteria multiply in the lungs causing either a flu-like illness or pneumonia.

Scientists from the UK Health Protection Agency discovered that professional drivers were five times more likely to be infected by the bug and carried out a study to determine the cause.

The researchers asked men and women in England and Wales who had Legionnaires' disease between July 2008 and March 2009 to fill in questionaires which focussed on driving habits and risk factors for the disease.

After analysing the data, they discovered that people most at risk of being infected drove a van, drove through industrial areas and often travelled in the car with the window down.

However, the biggest risk factor was found to be "driving or being a passenger in a vehicle with windscreen wiper fluid not containing screenwash."

In the study, published in the European Journal of Epidemiology, the authors said: "Not adding screenwash to windscreen wiper fluid is a previously unidentified risk factor and appears to be strongly associated with community acquired sporadic cases of Legionnaires' disease."

Legionalla bacteria may grow in the stagnant water of windscreen fluid resevoirs. When sprayed onto windscreens, aerosols carrying the bacterium could be sucked into the car, they speculated.

They also said it was plausible that screenwash inhibit the growth of the bacteria as they usually contain biocidal agents such as propranolol.

A small pilot study also carried out by the HPA isolated Legionella from the windscreen wiper fluid of one out of five cars without screenwash, but failed to detect the bacterium in sixteen cars which used screenwash.

This article was published on Mon 14 June 2010