The Southern Nevada Health District is investigating after guests reported getting Legionnaires’ disease at Caesars Palace and The Orleans.

According to district officials, two individuals who stayed at Caesars Palace were diagnosed within the last 12 months. They said previous environmental samples taken from the property tested positive for Legionella. However, the most recent environmental testing did not detect that bacteria.

For the second time this year, a guest was diagnosed with the disease after staying at The Orleans. Earlier this year, two cases were detected and the casino did remediation to the property’s water system. District officials said after those treatments, no Legionella bacteria was detected.