Monday, 14 June 2010
A study, conducted by the Health Protection Agency (HPA) indicates an association between not using a chemical screen wash in car wiper fluid and the risk of contracting Legionnaires' disease.
Legionnaires' disease is an infection caused by inhaling the bacterium Legionella pneumophila. The illness is characterised by an acute and potentially life threatening pneumonia. The infection cannot be caught from another person. It is spread through the air by breathing in very small droplets of water (between 1-5 microns in diameter) which contain the bacteria, from a contaminated water source,. Once in the lungs the bacteria multiply and cause either pneumonia (Legionnaires’ disease) or a flu-like illness without pneumonia called
fever. The majority of infections are reported as single (isolated or sporadic) cases but outbreaks are also seen. Pontiac
The study looked into the potential risk factors for vehicle drivers and passengers, given that most cases seem to be isolated, that Legionnaires' disease are often not traced to a source, and that drivers figure disproportionately among cases of sporadic Legionella infection.
Researchers conducted a case control study by interviewing 75 patients in
England and who had recovered from community acquired Legionnaires' disease between July 2008 and March 2009, and comparing them to a group of similar people whodidn’t have the disease. Wales
The study found two exposures, which had not been previously identified, associated with an increased risk of Legionnaires' disease:
- driving through industrial areas and
- driving or being a passenger in a vehicle without screen wash in its wiper fluid.
Additionally the Health Protection Agency, tested the windscreen wiper fluid in another sample of cars with and without added screen wash. Legionella bacteria were isolated from the windscreen wiper fluid of one car out of five that did not use screen wash while none were identified from 16 cars that did use screen wash. Screen wash usually contains agents that will stop the growth of bacteria.
From the results of these studies the researchers estimate that around 20% of community acquired sporadic cases under the age of 70 years in
England and could be prevented by using screen wash. Further studies are now required to go further in confirming this finding, and to see whether the use of screen wash in wiper fluid could play a role in preventing this disease. Wales
However, in the meantime it seems sensible that vehicle owners add screen wash to screen-washer fluid in order to prevent contamination by the legionella bacteria.
The study Windscreen wiper fluid without added screen wash in motor vehicles: a newly identified risk factor for Legionnaires' disease was published online in the European Journal of Epidemiology, on 8 June 2010 at: http://www.springerlink.com/content/t92532v54003150g/?p=d75c20f288574b48922a64e646a5223e&pi=2
More information about Legionnaires’ disease is available from the Public Health Wales website at: http://www.wales.nhs.uk/sitesplus/888/page/44350