It's still unclear how the health district linked the recent cases back to the Rio. One guest visited the hotel in March and the other visited in April.
The NYPD and Department of Health are launching their own investigations after receiving a report from the Patrolmen's Benevolent Association that found traces of the legionella bacteria at the 23 Precinct.
Legionella, the bacteria that causes the disease, was found in the hot-water system of one of the hotel's towers during a test after the second illness was reported in late May, said Mark Bergtholdt, the district's environmental health supervisor.
The disease, a form of pneumonia, is often caused by breathing in water vapor from cooling systems or water towers that contain the bacteria.
The Health Department began investigating the water at the precinct on Friday, when it was notified that the officer had been diagnosed with the disease and that the Legionella bacteria that causes it had turned up in the police station's water supply. Symptoms include fever, headaches, muscle aches and shortness of breath.
Health officials are advising the NYPD to not take hot showers in the precinct.
The majority of people who come in contact with the bacteria aren't sickened, health officials said. The Health District is reportedly working with the Rio Hotel & Casino for remediation and follow-up sampling in order to ensure their efforts are effective.
Most healthy people who are exposed to legionella don't get sick, the CDC says.
Once the guests' illnesses were confirmed, the Rio then inspected its water system.
Most at risk for the condition are people age 50 and above, smokers, immune-compromised individuals, chronic lung disease patients, and those with an existing medical problem, warned the CDC. There is about a 10 percent mortality rate for those who experience complications from the disease.
The Rio All-Suite Hotel and Casino is now hosting the 48 World Series of Poker, which started in late May and will conclude with the main event in mid-July.