/Legionnaires’ Disease (Legionellosis)

Legionnaires’ Disease (Legionellosis)

What is Legionnaires’ disease?

Legionnaires’ disease is a bacterial disease that may cause respiratory illness or pneumonia.

Why is it called Legionnaires’ disease or legionellosis?

The bacteria got its name in 1976, when many people who went to a Philadelphia convention of the American Legion suffered from an outbreak of this disease, a type of pneumonia (lung infection).

Subsequently, the bacterium causing the illness was named Legionella pneumophila and the name of the illness was changed to legionellosis.

Is this a new disease?

No. While the bacterium was only identified following the 1976 convention, earlier cases have been confirmed as early as 1947.

How widespread is Legionnaires’ disease?

According to the CDC, health departments across the country reported 6,100 cases of Legionnaires’ disease in 2016. Legionnaires’ is likely underdiagnosed and so the number of cases might be under reported as well.

How severe is the illness?

Legionnaires’ disease can be very serious and can even cause death. Most cases can be successfully treated with antibiotics, and healthy people usually recover from the infection.

Where are Legionella found?

Legionella naturally exist in the environment, usually in water. The bacteria grows best in warm water, and are most commonly found in water sources such as hot and cold water taps, hot water tanks, and water in air conditioning systems. They have also been found in misting systems, decorative fountains and whirlpool spas.

How do people get Legionnaires’ disease?

The disease is spread through breathing in tiny water droplets containing the Legionella bacteria. According to the CDC, in general, people do not spread Legionnaires’ disease to other people. However, this might be possible under rare circumstances. Outbreaks occur following the exposure of many individuals to a common source of the bacteria in the environment.

Who gets Legionnaires’ disease?

Most people who are exposed to Legionella do not get sick, but some people are more at risk than others. There are factors that can put people at an increased risk of getting sick: being age 50 years or older; being a current or former smoker; having a chronic lung disease (like chronic obstructive pulmonary disease or emphysema); having a weakened immune system or taking drugs that weaken the immune system (like after a transplant operation or chemotherapy); having cancer; or having underlying illnesses such as diabetes, kidney failure, or liver failure.

What are the usual symptoms of Legionnaires’ disease?

Symptoms of Legionnaires’ disease are similar to those of pneumonia so it may be difficult to diagnose. Signs of the disease can include: a high fever, chills, cough and fatigue or weakness. Some people may also suffer from muscles aches and headaches.

How soon do symptoms occur/appear?

Symptoms usually begin two to 14 days after exposure.

What is the treatment for Legionnaires’ disease?

Certain antibiotics are effective in treating the disease. Early diagnosis and treatment are important for recovery.

Why is Legionnaires’ disease so difficult to diagnose?

Legionnaires’ disease often causes symptoms similar to those caused by other organisms, including the influenza virus and other types of bacterial pneumonia.

Since diagnosis depends on a culture of the organisms, apositive urine antigen test, or comparison of blood tests taken during and several weeks after the illness, the diagnosis may not be confirmed until after the person is well.

When does the Health District investigate a case of Legionnaires’ disease?

All cases of Legionnaires’ disease are investigated, and efforts are always made to identify any risks for exposure. When an outbreak occurs, additional investigation efforts are conducted, like environmental water sampling, to look for a possible environmental source so that additional illness can be prevented.

Where can I get more information?

Visit the CDC Legionellosis Resource website, external link contact your doctor or the Southern Nevada Health District helpline at (702) 759-4636.

Contact Information

(702) 759-4636

Updated on: December 21, 2020

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