Windshield Washer Fluid is a Source of Legionnaires Say Scientists

Posted on May 19, 2014

Scientists have determined that Legionnaires disease may be able to grow in windshield washer fluid. The bacteria can cause serious respiratory illness. The research was presented at the annual meeting of the American Society for Microbiology.

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

Legionella are bacteria that are found naturally in the environment, usually in water. They are commonly associated with the cooling towers found in large-scale air conditioners and hot tubs. The bacteria is not spread from person to person but are transmitted via mist or vapor containing the bacteria. Studies suggest windshield washer fluid can spread the bacteria. It is possible something could be added to the fluid to prevent this from happening.

The results presented come from a series of experiments conducted in the summer of 2012. Schwake and his colleagues attempted to grow Legionella bacteria in a variety of different washer fluid preparations. They found that the bacterial concentrations increased over time and they were able to maintain stable populations for up to 14 months. In the second study, they tested the washer fluid from school buses in central Arizona and found culturable Legionella in approximately 75% of the samples. The image shows collected windshield washer fluid samples.

Schwake says, "This study is the first to detect high levels of Legionella in automobiles or aerosolized by washer fluid spray. While potential transmission of a deadly respiratory disease from a source as common as automobile windshield washing systems is significant, the study also points to the fact people can be exposed to pathogens - particularly those occurring naturally in the environment - in previously unknown and unusual ways."

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