Legionnaires Disease Outbreaks

What is a Legionnaires Disease Outbreak?

A Legionnaires disease outbreak occurs when two or more people are exposed to Legionella in the same place and get sick at about the same time.

Who Investigates Legionnaires Disease Outbreaks?

The investigation of a Legionnaires disease outbreak begins with two or more people getting sick. As legionnaires disease can be very serious, it often results in hospitalization. Once a lab test confirms that the patient is sick, the doctor must report their case.  Legionnaires disease is classified as a communicable disease. Because of this classification, whenever an individual is diagnosed with Legionnaires’ disease, their doctor must report it to the local health department.

The local health department then begins an investigation. They ask the patient where they have been for the last 2-12 days, and if they have traveled. The case is often reported to the Centers for Disease Control and Prevention (CDC). The CDC does not have to be involved but they often choose to be when there is an outbreak. They are helpful in the fact that they communicate with local health departments to determine who else could be involved in the outbreak and thus narrows down the possible sources of infection.

Therefore, a Legionnaires disease outbreak is often investigated by several different agencies, generally comprising of state and local health departments and the CDC.

Outbreaks and Recreational Water

One of the most common sources of Legionnaires disease outbreaks is recreational water, specifically hot tubs. CDC recently published in their Morbidity and Morality Weekly Report (MMWR) a report on Outbreaks Associated with Treated Recreational Water in the United States from 2015 through 2019.From 2015-2019, there were over 208 outbreaks in 36 states that were associated with treated recreational water. Most of these outbreaks, 199 out of the 208, occurred in public pools, hot tubs, or playgrounds. The outbreaks resulted in 3,646 cases of illness, 286 hospitalizations and 13 deaths. Among the 208 outbreaks, 71 (34%) were associated with a hotel or a resort, and 107 (51%) started during June–August.

42% of the outbreaks were caused by Legionella, the bacteria that causes Legionnaires’ disease. While only 42% of these outbreaks were caused by Legionella, 100% of the deaths were due to Legionnaires’ disease. This shows that Legionnaires’ disease is one of the most serious risks posed to people by recreational water.

Source: CDC’s Morbidity and Morality Weekly Report (MMWR) on Outbreaks Associated with Treated Recreational Water.

Outbreaks and Cooling Towers

The other major common source of Legionnaires disease is from cooling towers. As seen on our Legionnaires disease History Page, the first known outbreak of legionnaires disease in the United States was one caused by cooling towers.

A study published in the Journal of Emerging Infectious Diseases found that since 2006, 6 community-associated Legionnaires’ disease outbreaks have occurred in New York City alone, resulting in 213 cases and 18 deaths. Three outbreaks occurred in 2015, including the largest on record with 138 reported cases. Three of these outbreaks were specifically linked to cooling towers after environmental sampling.

Source: Fitzhenry, Robert et al. “Legionnaires’ Disease Outbreaks and Cooling Towers, New York City, New York, USA.” Emerging infectious diseases vol. 23,11 (2017): 1769–1776.

Water within cooling towers is heated and becomes an ideal environment for Legionella heat-loving bacteria to grow. Legionnaires’ disease can be acquired when an individual breathes in water droplets containing Legionella bacteria. Cooling towers function to cool large buildings, and in the process heated and evaporated water flows out the top of the tower in the form of a mist. If a cooling tower is not maintained properly, this mist can contain the Legionella bacteria. This mist has the potential of infecting innocent pedestrians who happen to walk near the cooling tower.

Source: CDC

Contact A Legionnaires Disease Lawyer

If you believe you have been exposed to Legionnaires Disease, please do not hesitate to contact us today. We will review your case and help you determine if you are eligible for financial compensation. We will fight on your behalf, regardless of how long it takes. Please request your free consultation or call us at 215-988-0160.

Learn More About Legionnaires Disease Outbreaks

For more information about Legionnaires disease outbreaks, check out our previous blog posts:

Legionnaires Disease Outbreak was last modified: July 28th, 2021 by zacherlaw