{"id":1005,"date":"2016-02-12T10:47:16","date_gmt":"2016-02-12T15:47:16","guid":{"rendered":"https:\/\/www.vdh.virginia.gov\/epidemiology\/?page_id=1005"},"modified":"2025-08-07T17:21:43","modified_gmt":"2025-08-07T21:21:43","slug":"legionellosis","status":"publish","type":"page","link":"https:\/\/www.vdh.virginia.gov\/epidemiology\/epidemiology\/epidemiology-fact-sheets\/legionellosis\/","title":{"rendered":"Legionellosis"},"content":{"rendered":"
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What is legionellosis?<\/h2>\n

Legionnaires\u2019 disease and Pontiac Fever are collectively known as Legionellosis. These diseases are caused by Legionella <\/em>bacteria. \u00a0Legionnaires' disease is a serious disease that can cause pneumonia (lung infection). Pontiac fever is caused by the same bacteria but causes a milder respiratory illness. Rarely, Legionella<\/em> can cause infection outside the lungs, such as heart or wound infections. This is called an extrapulmonary infection.<\/p>\n

Who gets legionellosis?<\/h2>\n

Most healthy people exposed to Legionella <\/em>don\u2019t get sick. People at increased risk of getting sick include current or former smokers, people 50 years or older, and people with specific health issues or conditions.<\/p>\n

How is legionellosis spread?<\/h2>\n

Legionella<\/em> bacteria are found naturally in the environment. The bacteria can become a health concern when they grow and spread in human-made building water systems like showerheads and sink faucets, hot tubs, decorative fountains and water features, and cooling towers. People most commonly get sick by breathing in mist, or small droplets of water that contain the bacteria. People can also get sick by accidentally swallowing (aspirating) water into the lungs. In general, the bacteria do not spread from person to person.<\/p>\n

What are the symptoms of legionellosis?<\/h2>\n

Legionnaires\u2019 disease can have symptoms like many other forms of pneumonia, so it can be hard to diagnose at first. Signs of the disease can include a high fever, chills, and a cough. Some people might also have muscle aches and headaches. The pneumonia can be very serious and about 1 in 10 people with Legionnaires\u2019 disease die. Symptoms of Pontiac fever can also include fever, headaches, and muscle aches, but there is no pneumonia.<\/p>\n

How soon after exposure do symptoms appear?<\/h2>\n

For Legionnaires' disease, symptoms usually appear 2\u201314 days after exposure, with an average of 5\u20136 days. For Pontiac fever, symptoms usually appear 5\u201372 hours after exposure, with an average of 24\u201348 hours.<\/p>\n

How is legionellosis diagnosed?<\/h2>\n

A chest x-ray can confirm if someone has pneumonia. Laboratory tests can be used to find Legionella<\/em> bacteria in the body. The most commonly used test is the urinary antigen test, which detects the bacteria in a urine sample. The disease can also be diagnosed by culture, when the bacteria are grown in the lab from sputum (phlegm) or other respiratory (lung) secretions.<\/p>\n

What is the treatment for legionellosis?<\/h2>\n

Antibiotics are used to treat Legionnaires' disease. Patients with pneumonia might also require hospitalization, oxygen, and other medical care. Most patients with Pontiac fever get better within 2\u20135 days without treatment.<\/p>\n

Do people who have been in contact with someone with legionellosis infection need to be tested and treated?<\/h2>\n

People who have been in contact with someone with legionellosis infection do not need to be tested. Legionellosis is not generally considered infectious between people. If someone visited the same areas with water as the sick person, they may also have been exposed to a contaminated water source and should monitor for illness.<\/p>\n

How can legionellosis be prevented?<\/h2>\n

The key to preventing legionellosis is to reduce the risk of Legionella <\/em>growth and spread. Building owners and managers can use a water management program to help control Legionella.<\/em> There are steps to take at home to avoid getting sick from germs that grow in pipe slime and devices that use water, like humidifiers. People with hot tubs and whirlpool baths should follow manufacturers\u2019 recommendations for cleaning and maintenance to keep them clean and free of Legionella<\/em> bacteria.<\/p>\n

How can I get more information about legionellosis?<\/h2>\n