A pair of recent visitors contracted Legionnaires’ disease while staying at the Rio All-Suite Hotel and Casino in Las Vegas, the Southern Nevada Health District announced. The two guests stayed at the hotel separately in March and April.

The Caesar Entertainment group said tests made to the hotel’s hot-water system confirmed the presence of the Legionella bacteria in one of the hotel’s two towers. Testing was conducted in late May.

Remediation efforts continue at the hotel, including disinfecting the system with chlorine. Guests in rooms served by the infected system were relocated, and those rooms will not be occupied until the system is flushed, according to Mark Bergtholdt, the district’s environmental health supervisor.

The hotel is “assisting in the investigation and taking steps to provide information to past and current guests of the property,” the health district wrote in its news release. Individuals who stayed at the hotel more than two weeks ago and have yet to develop symptoms are no longer at risk. Guests exhibiting symptoms within 14 days of their stay should seek medical attention.