Failure to add windscreen wash to a vehicle's windscreen wiper water could account for around 20 percent of cases of Legionnaires' Disease, according to the Health Protection Agency.
The disease -- caused by the Legionella bacteria -- is commonly associated with water systems such as air conditioning units, showers and fountains. When inhaled the bacteria can cause pneumonia.
However, this is the first time a link has been made between the disease and windscreen fluid.
Adding screen wash could mitigate the transmission of Legionella bacteria to drivers and passengers, the HPA said, in a report published in the European Journal of Epidemiology last week.
An HPA spokesperson said: "This preliminary HPA study suggests a strong association between a lack of screen wash in wiper fluid and the incidence of Legionnaires' disease.
"Further studies are now needed to determine whether the use of screen wash in wiper fluid could play a role in preventing this disease."
The HPA carried out the study after finding that cases of the potentially fatal disease were five times more prevalent among professional drivers in England and Wales than expected.
The agency contacted all survivors in England and Wales who had contracted Legionnaires' between July 2008 and March 2009.
Willing participants were questioned on their driving habits, possible Legionella sources in vehicles and known risk factors.
The study -- which looked at 75 cases and 67 controls -- also identified an increased risk of infection from driving through industrial areas, where there is likely to be a greater exposure to outside sources of Legionella.
This was the most likely explanation for the higher percentage of cases among professional drivers, analysts said.
Driving or travelling as a passenger in a van, driving with a window open and driving for long periods of time also increased the risk of infection -- all factors which may be linked to driving through industrial areas.
Also associated with an increased risk were driving an older vehicle and not using showers at home.
However, the report's authors said the findings on windscreen wash were "the most intriguing", concluding that 20 percent of Legionnaires' cases could be avoided by adding screen wash.
"This simple public health advice may be of worldwide relevance in reducing morbidity and mortality from Legionnaires? disease," the report stated.
Between 400 and 550 cases of Legionnaires' Disease have been reported in England and Wales in the last two years, with around one third of those infected as a result of travel to another country.
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