JEFFERSON CITY, Mo. -- Missouri health officials are tightening the requirements for reporting the severe form of pneumonia known as Legionnaires' disease.

The St. Louis Post-Dispatch reported the Missouri Department of Health and Senior Services made an emergency rule change earlier this month requiring health providers to report evidence of Legionnaires' within one day instead of three.

Department chief Randall Williams said the change will help the state act more aggressively in stopping the spread of the disease.

The U.S. Centers for Disease Control and Prevention said the number of cases of Legionnaires' rose by 500% from 2000 to 2017. The Missouri health department says 814 people in Missouri have contracted Legionnaires' since 2014.

The disease is not spread from person-to-person contact but by breathing infected mist or steam.

Information from: St. Louis Post-Dispatch, http://www.stltoday.com