The Southern Nevada Health District (SNHD) announced on Thursday it is looking into three cases of Legionnaires’ disease in guests who stayed at two Las Vegas hotels recently.

In two separate releases, the SNHD said it looking into “two travel-associated cases of Legionnaires’ disease in guests who stayed at Caesars Palace Hotel and Casino” and one “travel-associated case of Legionnaires’ disease in a guest that stayed at The Orleans Hotel & Casino.”

Legionnaires’ disease is a serious type of pneumonia caused by the Legionella bacteria.

The SNHD said guests who visited the hotels from Aug 1. on and “experienced symptoms up to 14 days after their stay” can report their illness to the Health District. The Caesars Palace release also featured an end date of Aug. 23 as the time period during which guests should be wary of the disease.

“Symptoms of Legionnaires’ disease will usually begin within two to 10 days after exposure to the bacteria. However, people should watch for symptoms such as cough, shortness of breath, fever, muscle aches and headaches for up to two weeks after exposure,” the SNHD said in both releases. 

The releases also feature warnings for “people who are at increased risk of getting sick” from the disease, including “people 50 years or older,” “current or former smokers” and “people with weakened immune systems.” 

This story was updated at 9:35 p.m. EST.