Windshield Washer Fluid May Cause Legionnaires' Disease, Study Finds | Edmunds

Windshield Washer Fluid May Cause Legionnaires' Disease, Study Finds

Just the Facts:
  • Bacteria found in automobile windshield washers may cause the potentially fatal Legionnaires' disease, according to a new medical study.
  • Researchers from the University of Arizona released the findings of their study at a meeting of the American Society for Microbiology.
  • The researchers were able to grow the bacteria in a variety of washer fluids and found it in the fluid of 75 percent of the school buses they sampled.

BOSTON — Your car's windshield washer reservoir may be acting as a petri dish for breeding the bacteria responsible for the potentially fatal respiratory illness known as Legionnaires' disease.

It might sound like the kind of "film at eleven" scare tactic heard on teasers for local TV news programs, but those are the findings of a research study released at the annual meeting of the American Society for Microbiology in Boston.

"Washer fluid spray can release potentially dangerous numbers of these bacteria into the air," said Otto Schwake, a doctoral student at Arizona State University, who presented the research. "These results suggest that automobiles may serve as a source of transmission for Legionella infections."

Schwake and his colleagues conducted a series of experiments in which they grew Legionella bacteria in a variety of washer fluids. They found that concentrations of the bacteria actually increased over time and were able to remain viable for up to 14 months.

The researchers then tested samples of washer fluid from school buses in a central Arizona district and found that 75 percent of them contained the bacteria.

Although windshield washers were not previously proven to be associated with Legionnaires' disease, the Arizona State University study was prompted by reports that risk of the illness increased with motor vehicle use. One such study, from the U.K., found that almost 20 percent of otherwise unexplainable cases in that country were linked to automobile washer fluid.

According to the ASM, Legionella bacteria are found naturally in the environment, usually in water, often in water tanks, hot tubs and large commercial air-conditioning systems.

The Mayo Clinic's Web site notes that the disease is not transmitted by person-to-person contact, but rather from inhaling mist containing the bacteria. Most people who come in contact with the bacteria don't become ill, but among those who do, symptoms can include headache, muscle pain, chills, fever and respiratory distress. If untreated, the disease can be fatal.

The name Legionnaires' disease was applied to the condition when, in July 1976, a group of people attending an American Legion convention in Philadelphia developed severe pneumonia-like symptoms. Of the 182 individuals affected, 29 died. The following January, researchers identified the cause as a previously unknown bacteria that they named Legionella.

Edmunds says: Just a suggestion: Keep windows rolled up when using windshield washers.

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