Las Vegas Hotels Investigated Over Legionnaires' Disease

Two renowned hotels and casinos in Las Vegas are being investigated by health authorities after several guests staying at them came down with Legionnaires' disease, a "serious" form of pneumonia caused by a bacterial infection.

The Southern Nevada Health District (SNHD) announced it was looking into how the cases occurred on Thursday, after two guests who had stayed at Caesars Palace and one at The Orleans were found to have been infected with Legionella bacteria.

The local health watchdog said the cases were "travel-associated" and that environmental samples taken from both properties had tested positive for the bacteria. It added that the hotels were cooperating and remedial work was underway.

As well as pneumonia symptoms, Legionnaires' disease can cause diarrhea, nausea and confusion among those infected, according to the Centers for Disease Control and Prevention (CDC). Symptoms usually present themselves within two to 14 days after exposure to the bacteria, but they can sometimes take longer to occur.

The bacteria that causes the disease is found naturally occurring in freshwater sources, but it becomes a health concern when spread into water systems designed for human use. In these cases, small droplets are either inhaled by people or, less commonly, ingested by drinking the contaminated water, the CDC says.

"There's nothing fancy about it at all; it simply gets into the air," David Katz, emeritus professor of immunology at University College London, told Newsweek. "It shouldn't be allowed to be in air conditioning, it shouldn't be allowed to be in showers or whatever—and it's allowed to be because people aren't monitoring for its existence."

The SNHD said that there had been two cases within the last 12 months at Caesars Palace, on the Las Vegas Strip, which had since "conducted remediation of the water system."

It added: "The most recent environmental testing did not detect Legionella bacteria. Steps to notify guests of the potential for exposure and ways to minimize risk are underway."

The health authority also noted that The Orleans, which sits on Tropicana Avenue, had seen two confirmed cases of Legionnaires' Disease earlier in the year, but remediation work had successfully removed the bacteria from the water system.

However, it said that "a third guest of the property was recently identified as a case, and environmental samples have tested positive for Legionella" again.

"The facility is cooperating with the Health District's investigation and undergoing remediation and environmental testing to ensure elimination of the bacteria to protect the health and safety of its guests," the SNHD added.

The Las Vegas-based government agency warned that those aged over 50, those with a pre-existing lung disease or who are immunocompromised, and smokers were at increased risk of contracting the disease.

It urged anyone who stayed at Caesars Palace between August 1-23, or at The Orleans from August 1, and who has since experienced symptoms of the disease to report their illness via a survey.

"We know the causes, we know how it spreads and we know it creates a respiratory problem," Katz said, adding cases required "investigative building work" rather than an immunological probe.

Katz explained that, as it was a disease that attacked the respiratory system, the most likely source of infection was from contaminated air conditioning systems.

He suggested infections of Legionnaires' disease—which gets its name from a 1976 outbreak at a hotel hosting an American Legion conference, attributed to the building's air conditioning system—were more probable in southern U.S. states because "the southern Unites States exists because of air conditioning."

A spokesperson for Caesars Entertainment, which owns Caesars Palace, told Newsweek that it was aware of the investigation and said the cases were "reported by guests who stayed at Caesars Palace approximately seven months apart in 2022 and 2023."

"Caesars Palace maintains a robust safety program to minimize the potential for the Legionella bacteria to survive in the water systems at its property that meet or exceed industry standards," they added. "We are confident in the integrity of our systems and the safety protocols we rigorously follow."

A spokesperson for the Boyd Gaming Corporation, which owns The Orleans, responded that Legionella bacteria had not been detected in the room where the guest who had come down with the illness had stayed, but that it was continuing to "work closely" with the investigation.

"The health and safety of our guests are extremely important to us, and we have extensive measures in place to minimize risk to our guests," they said.

News of the infections comes less than two weeks after the SNHD was reported to have found cases of bedbugs in seven hotels in the city, including at several of its most glamorous locations, such as the MGM Grand and Caesars Palace.

Update 08/26/23, 4:02 a.m. ET: This article was updated to include comment from spokespeople for Caesars Entertainment and the Boyd Gaming Corporation.

Update 08/30/23, 12:24 p.m. ET: This article was updated to include comment from Professor David Katz.