Sioux Falls Legionnaires cases increase; CDC asked to help

A sharp rise in Sioux Falls Legionnaires cases has spurred the South Dakota Department of Health (DOH) to seek assistance from the Centers for Disease Control and Prevention (CDC), according to a news release by the state.

There have been 14 confirmed cases of Legionnaires’ disease in Sioux Falls, including one death. All of the cases required hospitalization.

Overall in South Dakota in 2018, there have been 24 cases of Legionnaires’ disease, a severe type of pneumonia (lung infection). The state typically sees between eight and 15 cases a year.

In an interview with KELOLAND News, state epidemiologist Dr. Joshua Clayton said: “This is something that we wanted to raise awareness, specifically to help identify additional individuals who may be ill within the community that should be seeking their health-care provider for testing.

“This is not a huge concern in terms of the overall risk. What we’re seeing is a general increase.”

The South Dakota Department of Health has asked for help from the CDC after an alarming increase in Sioux Falls Legionnaires cases.

Sioux Falls Legionnaires: hunt is on

The DOH said patients have been interviewed as the department tries to identify commonalities, pinpoint possible exposure areas, and determine the source of the illnesses. Sioux Falls health-care providers have been notified of the increase.

Because of the similarity of Legionnaires’ disease to other forms of pneumonia, it often goes undetected. Special laboratory tests need to be performed to determine if the illness is indeed Legionnaires’ disease.

“In addition to enhanced case investigations, CDC will assist us with environmental assessments and testing to identify water sources that may contain the Legionella bacteria,” Clayton said, referring to the bacteria that causes Legionnaires’ disease. “However, it is often the case that a single source may not be found.”

Sioux Falls Legionnaires: public warned

When Legionnaires’ disease cases are reported, they are usually referred to in the following terms:

• Outbreak: Used if two or more cases are reported within days or weeks, rather than months, and they happen in a limited geographic area – that is, officials can pinpoint a specific area where the illnesses occurred.
• Cluster: Used if two or more illnesses occur in the same general vicinity within a longer time span (three months to a year).
• Community-acquired: Used when there are no commonalities; these kinds of cases are the most common.

The DOH has not classified the situation in Sioux Falls.

Sioux Falls Legionnaires: more on the disease

Legionnaires’ disease is also called legionellosis or Legionella pneumonia, and according to the CDC, an estimated 25,000 cases occur in the United States yearly. Only 5,000 cases are reported, however, because of the disease’s nonspecific signs and symptoms.

Legionella bacteria are contracted by inhaling microscopic water droplets (vapor or mist). The bacteria grow best in warm water, and they are found primarily in human-made environments.

Why the increase?
In a 2017 interview, Laura Cooley, MD, MPH from the CDC’s Respiratory Diseases Branch, called Legionnaires’ disease “an emerging disease in the sense that the number of recorded cases of Legionnaires in the United States continues to increase.” She said the increase is because the population has become more susceptible – that is, more and more people are on immunosuppressive medications.

Cooley went on to say that there are more Legionella bacteria in the environment, because warmer temperatures are creating the optimal conditions for bacterial growth. Seventeen of the 18 warmest years since modern record-keeping began have occurred since 2001, according to analyses by both the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA).

Further, the four warmest years on record have occurred since 2014, with 2017 being the warmest non-El Niño year recorded. This year is shaping up to be the fourth-hottest year on record. The only years hotter were the three previous ones.

Where does the bacteria grow?
Outbreaks and clusters have been linked to a number of sources:

• cooling towers of air conditioning systems
• large plumbing systems
• bathroom faucets and showers
• hot-water heaters and tanks
• swimming pools, hot tubs and whirlpools
• decorative fountains
• mist machines, like those used in the produce sections of grocery stores
• hand-held sprayers
• physical-therapy equipment
• water systems, like those used in hotels, nursing homes, and hospitals.