Legionellosis is caused by bacteria called Legionella. The disease has two different forms. Legionnaires’ disease is the more severe form of infection that causes pneumonia. Pontiac fever is caused by the same bacteria, but is a milder illness without pneumonia.
The disease got its name after a group of people attending a convention of the American Legion in Philadelphia in 1976 developed pneumonia. While the Legionella bacteria were around before 1976, scientists had never been able to find it in an ill person’s lungs before that time.
People at risk:
Cases of legionellosis are more common in individuals who are 50 years of age or older, smokers, people with chronic lung disease, and individuals with weakened immune systems.
Mode of spread:
Legionella is naturally found in water and it is usually spread through water droplets in the air. One can get infected with Legionella when one breathes in contaminated water droplets.
There have been Outbreaks from exposure to aerosols generated form shower heads, cooling towers, mist machined, and other aerosols. Legionella grow best under a temperature of 40o C to 50o C and they have been known to survive in water chlorination. Legionella can colonize the water systems of hospitals and large buildings.
Common Sources of contaminated droplet:
We have seen cases of Legionaries’ disease tripled from 2005 to 2017. We also noticed that it is more common in men than women. The incidence is higher between May and October. Outbreaks of Legionaries’ disease in Virginia have been associated with Nursing Homes, Private Homes and Gyms and Spas. Annual Report.
Water systems in buildings should be well maintained in order to reduce risk of legionella colonization and spreading. Legionellosis is not a vaccine preventable disease. Link
Enhancement to Legionella surveillance:
- To improve the understanding among state and local health department staff regarding maintenance strategies and primary prevention of Legionnaires’ disease.
- To foster a knowledge base, upon which we can develop maintenance strategies and measure its efficacy.
- To identify existing barriers to integrating maintenance strategies within current regulatory functions (i.e. building permits, facility inspections, etc.).
- To assess water maintenance plan for vulnerabilities
Contact your local Health Department Link or Department of Environmental Epidemiology Link for Legionella sampling.
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