Windshield washer fluid in vehicles is generally considered pretty innocuous, except for the expected warnings not to consume it, get it in your eyes or rub it all over your skin. But a recent study found that a significant number of school buses had fluid that was harboring a potentially harmful pathogen.

Windshield washer fluid was found to be a medium that grows a bacteria that can cause respiratory illness. (Photo credit: Shutterstock)

Windshield washer fluid was found to be a medium that grows a bacteria that can cause respiratory illness. (Photo credit: Shutterstock)

Researchers from Arizona State University tested school buses from one district in Arizona and found a bacteria associated with respiratory illnesses was growing in 75 percent of them.

“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,” Otto Schwake, a doctoral student at the university who presented his findings at the American Society for Microbiology Monday, said in a statement.

You might be wondering what prompted scientists to test windshield fluid for the bacteria Legionella in the first place. Schwake said previous studies have found that use of motor vehicles seemed linked with an increase risk for Legionnaires’ disease, a type of pneumonia caused by inhaling the bacteria in a mist. The bacteria are not transferred from person to person but can come from sources like hot tubs, showers or air-conditioning, according to the National Institutes of Health.

A couple of years ago, Schawke and his colleagues grew the bacteria in washer fluid in the lab, finding that its concentrations would increase over time. Their latest findings went straight to school buses’ fluid storage tanks, in which they found Legionella that they could culture in 75 percent of their samples.

“This study is the first to detect high levels of Legionella in automobiles or aerosolized by washer fluid spray,” Schwake said.  “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.”

(H/T: Popular Science)

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