Guess where researchers found the bacteria that cause Legionnaires’ disease?
Now a researcher at Arizona State University has discovered that the bacteria can live in some brands of windshield washer fluid and flourish in the motor vehicle reservoirs that contain it. When sprayed, some of the droplets can be inhaled by vehicle occupants, especially people like bus drivers who are behind the wheel for extended periods.
Legionella pathogen thrives in windscreen wiper
fluid, can find its way into vehicles, researchers say
The potentially deadly legionella pathogen can
thrive in car windscreen wiper fluid, new research in the United States has
found.
Arizona State University researchers examined a series of school
buses across different seasons and found high concentrations of legionella
bacteria in the fluid, which also found its way into the cabins of the buses at
high levels.
Doctoral student Otto Schwake said the research uncovered some
"pretty startling stuff".
"I was actually surprised by the positivity and
concentration we were seeing," he said.
"Every single bus we looked at, on at least one sampling
period, had live, culturable legionella."
Those recordings came from inside the fluid containers but
"probably more disturbing" were the findings inside the buses after
the windows had been sprayed, Mr Schwake said.
"When we performed air sampling while the buses were
washing their windows, we found concentrations as high as 120 cells per cubic
metre," he said.
"Just as a point of reference, a lot of outbreaks that
occur for legionnaire's disease report concentrations from 10 to 200 ... so it
falls within that range."
Mr Schwake said one bus was found to be carrying almost one
billion legionella pneumophila, a known human pathogen species.
What is Legionella Pathogen
From Wikipedia, the free encyclopedia
The genus Legionella is a pathogenic group of Gram-negative bacteria that includes the species L. pneumophila, causing legionellosis[3] (all illnesses caused by Legionella) including a pneumonia-type illness called Legionnaires' disease and a mild flu-like illness called Pontiac fever.[3]
Legionella may be visualized with a silver stain or cultured in cysteine-containing media such as buffered charcoal yeast extract agar. It is common in many environments, including soil and aquatic systems, with at least 50 species and 70 serogroups identified. The bacterium, however, is not transmissible from person to person:[4] furthermore, most people exposed to the bacteria do not become ill.[5]
The side chains of the cell wall carry the bases responsible for the somatic antigen specificity of these organisms. The chemical composition of these side chains both with respect to components and arrangement of the different sugars determines the nature of the somatic or O antigen determinants, which are essential means of serologically classifying many Gram-negative bacteria.
Legionella acquired its name after an outbreak of a then-unknown "mystery disease" sickened 221 persons, causing 34 deaths. The outbreak was first noticed among people attending a convention of the American Legion—an association of U.S. military veterans. The convention occurred in Philadelphia during the U.S. Bicentennial year in July 21–24, 1976. This epidemic among U.S. war veterans, occurring in the same city as—and within days of the 200th anniversary of—the signing of the Declaration of Independence, was widely publicized and caused great concern in the United States.[6]
On January 18, 1977, the causative agent was identified as a previously unknown bacterium subsequently named Legionella. See Legionnaires' disease for full details.
Sources of Legionella
Documented sources include cooling towers,[16] swimming pools (especially in Scandinavian countries), domestic water systems and showers, ice-making machines,[17] refrigerated cabinets, whirlpool spas,[18][19] hot springs,[20] fountains,[21] dental equipment,[22] soil,[23]automobile windshield washer fluid,[24] and industrial coolant.[25]
Airborne transmission from cooling towers
The largest[26] and most common source of Legionnaires' disease outbreaks are cooling towers (heat rejection equipment used in air conditioning and industrial cooling water systems) primarily because of the risk for widespread circulation. Many governmental agencies, cooling tower manufacturers, and industrial trade organisations have developed design and maintenance guidelines for controlling the growth and proliferation of Legionella within cooling towers.
Research in the Journal of Infectious Diseases (2006) provided evidence that L. pneumophila, the causative agent of Legionnaires' disease, can travel at least 6 km from its source by airborne spread. It was previously believed that transmission of the bacterium was restricted to much shorter distances. A team of French scientists reviewed the details of an epidemic of Legionnaires' disease that took place in Pas-de-Calais, northern France, in 2003–2004. Of 86 confirmed cases during the outbreak, 18 resulted in death. The source of infection was identified as a cooling tower in a petrochemical plant, and an analysis of those affected in the outbreak revealed that some infected people lived as far as 6–7 km from the plant.[27]
Australian researchers set to help probe risk
While the high level of pathogens in the air is concerning, Mr
Schwake says it is not yet conclusive that it is a significant risk and that it
leads to people getting sick or dying from legionella.
"Whether or not it's posing a significant risk or even a
risk at all we won't know until we do more research," he said.
The research says legionella is often under-reported, except in
Australia where greater knowledge of the pathogen has led to higher reporting.
Mr Schwake says Australian researchers are going to help test his findings.
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"We actually have a nice collaboration hopefully going on
with a public health group from Australia that are planning to look at sources
of legionella transmission, including washer fluid," he said.
It is hoped the Australian group will help Mr Schwake identify
whether this is a significant problem that needs to be investigated, or whether
the fact that legionella survives in washer fluid is just an interesting
anomaly with no significant public health concerns.
But given that winding up the windows appears to do little to
protect against the pathogen's entry into a vehicle, Mr Schwake says it is a
case of "picking your poison".
Other research has previously found windscreen washing fluids
introduce potentially toxic levels of methanol into the cabin of cars.
Mr Schwake says legionella, which has previously been identified
in air conditioners, water cooling towers and bags of potting mix, can also
grow on air filters and even sterilizing the water is not a clear-cut solution.
"We chlorinate our water in America, probably in Australia
as well, to reduce pathogens," he said.
"But legionella's unique in that ... a single cell gets
past the treatment process, establishes a foothold in a new environment, and it
can actually grow."
Read more here.
Pneumonia Bacteria May Lurk in Windshield Washer Fluid
Windshield washer fluid a source of Legionnaires: Found in most school buses
A form of bacteria responsible for respiratory illness, including the deadly pneumonia known as Legionnaire's disease, may be able to grow in windshield washer fluid and was isolated from nearly 75% of school buses tested in one district in Arizona.
Credit: Otto Schwake
A form of bacteria responsible for respiratory illness, including the deadly pneumonia known as Legionnaire's disease, may be able to grow in windshield washer fluid and was isolated from nearly 75% of school buses tested in one district in Arizona, according to research presented today at the annual meeting of the American Society for Microbiology.
"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," says Otto Schwake, a doctoral student at Arizona State University, who presented the research.
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. They are not spread from person to person but instead are transmitted via mist or vapor containing the bacteria. Most people exposed to the bacteria do not become ill, but in some people it can cause Legionnaires' disease, a severe form of pneumonia. The bacteria can also cause Pontiac fever, a milder illness resembling the flu.
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.
Although windshield washer fluid is not normally associated with spreading disease, Schwake says this project was begun after a series of epidemiological studies found motor vehicle use to be associated with increased risk for Legionnaires' disease. One such study attributed nearly 20 percent of Legionnaires' disease cases in the United Kingdom not associated with hospitals or outbreaks to automobile windshield washer fluid.
"This study is the first to detect high levels of Legionella in automobiles or aerosolized by washer fluid spray," says Schwake. "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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