Legionnaire bacteria spread by Windshield Wiper Fluid
May 19, 2014

Windshield Wiper Fluid Linked To Legionnaire’s Disease

Brett Smith for redOrbit.com - Your Universe Online

Windshield washer fluid is one of those innocuous things you probably don’t give much thought to throughout the day, but a new study has found that the familiar blue fluid often harbors the bacteria that causes Legionnaire’s disease.

Spread via mist or vapor containing the Legionella bacteria, Legionnaire’s disease is essentially a severe form of pneumonia. The same bacteria can also cause Pontiac fever – a flu-like illness. Most people who come in contact with the bacteria do not fall ill.

Given its name after an outbreak at a conference of the American Legion in Philadelphia in 1976, Legionnaire’s disease is typically associated with hot tubs and water heating systems.

"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," said Otto Schwake, a doctoral student at Arizona State University who presented the research on Sunday at the annual meeting of the American Society for Microbiology being held in Boston.

Schwake added that the research was inspired by a series of epidemiological research studies that discovered motor vehicle use is connected with greater risk for Legionnaires' disease. One of these previous studies attributed almost 20 percent of Legionnaires' disease cases in the United Kingdom not linked with medical centers or outbreaks to windshield washer fluid.

Conducted in the summer of 2012, the study tested the ability of Legionella bacteria to grow in a number of different washer fluid treatments. They discovered that the bacterial levels increased with time and they were able to preserve stable populations for approximately 14 months. In a second trial, they tested washer fluid samples from school buses in Arizona and discovered Legionella in about 75 percent of the samples.

“Washer fluid has the traits a potentially dangerous source of Legionella exposure needs,” Schwake said. “It is aerosolized, heated and people are regularly exposed to it. The results from this study support previously demonstrated epidemiological evidence for a link between automobiles and Legionnaires’ disease by providing microbiological data on survival, presence and transmission of Legionella in washer fluid.”

The Arizona researcher told Bloomberg reporter Nicole Ostrow that, despite his study’s conclusions, it might be a bit premature to start enacting any new safety precautions.

“We are exposed to an enormous number and variety of microbes every day from countless sources, the overwhelmingly vast majority of which are harmless,” he said. “That being said, unknown sources of pathogen transmission certainly exist and need to be studied. Due to the sheer lack of data, I believe any study examining the relationship between Legionella and automobiles would be greatly useful.”

In January, researchers from Arizona State University found that hard water scaling on the interiors of domestic water pipes can increase risk for exposure to Legionnaire’s disease via the growth of bacteria-fostering biofilms. They noted that growth and development of biofilms depends upon a various factors such as water flow rates in addition to the distinct plumbing materials.

Image 2 (below): This image shows collected windshield washer fluid samples. Credit: Otto Schwake