The South Dakota Department of Health is calling federal reinforcements to investigate an outbreak of Legionnaire's disease centered around Sioux Falls.

The disease has hospitalized 14 and killed 1, the department said Thursday. The confirmed cases have been reported in people who reside or traveled to Sioux Falls.

The Department of Health has requested the assistance of the Centers for Disease Control and Prevention to investigate the sharp increase in cases of the disease, a type of pneumonia caused by the Legionella bacteria.

“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," said Dr. Joshua Clayton, state epidemiologist, in a news release. "However, it is often the case that a single source may not be found.”

The state typically sees between 8-15 cases each year. As of Sept. 20, there have been 24 cases reported in the state this year, which mirrors a national increase, the Department of Health said.

All Legionnaire's patients were between the ages of 36 and 80, with a median age of 57. Most people exposed to the bacteria don't develop the disease. But those over the age of 50, smokers and weakened immune systems or chronic health conditions are at increased risk.

Legionnaire's is spread by inhaling the fine spray from water sources containing the Legionella bacteria. It occurs more frequently in hot, humid weather. Cases in other states have been associated with cooling towers in air-conditioning systems, decorative fountains and hot tubs. The bacteria is not spread person to person by consuming drinking water.

Symptoms include muscle aches, chills, shortness of breath, headache, fatigue, loss of appetite and coughing. These symptoms may be followed by high fever and pneumonia. Anyone experiencing these symptoms should seek medical help.

The state Health Department is conducting in-depth interviews with patients to investigate potential sources of exposure to the disease. The department has also notified Sioux Falls healthcare providers about the increase in cases. The Sioux Falls Health Department will be coordinating outreach to local businesses.

For more information on Legionnaire's disease, visit: http://doh.sd.gov/news/legionnaires.aspx