The state Department of Health on Saturday confirmed a fifth case of Legionnaires’ disease in a guest who stayed at the Grand Islander by Hilton Grand Vacations in Waikiki.

The case was diagnosed May 23, according to a DOH news release. The individual, who is not a resident of Hawaii, began their stay at the Grand Islander on April 25.

“DOH continues to work to ensure that the Grand Islander takes action to remediate the building and other possible sources of exposure,” said State Epidemiologist Dr. Sarah Kemble in a news release. “Individuals who stay at the Grand Islander should keep these recent cases in mind, and if they have flu-like symptoms following a stay at the hotel, should seek medical care immediately.”

Health officials said the first case at the Grand Islander was diagnosed in June; the second case in early March; the third case on April 2; and the fourth case on April 26.

“The Grand Islander continues to work with DOH to ensure that the building is remediated. Mitigation measures include installing point-of-use filters in guest room showers,” the release said.

“Our top priority at The Grand Islander is to provide a safe environment for our owners, guests, and team members,” a spokesperson for the company said in a written statement. “We have been working closely with the Hawaii Department of Health as they conduct their investigation. We have also engaged leading experts and under their direction and are implementing additional precautionary measures at The Grand Islander to ensure our safeguards are in line with best practices.”

Legionnaires’ disease is a type of pneumonia caused by exposure to Legionella bacteria. It is treated with antibiotics and cannot spread from person to person, according to DOH. Legionella bacteria are commonly found in warm freshwater environments but can proliferate and spread in water systems such as showerheads and sink faucets, cooling towers, hot tubs and large plumbing systems.

Most healthy people exposed to Legionella bacteria do not develop Legionnaires’ disease, DOH said. Those at increased risk include people age 50 and older, current or former smokers, and people with chronic lung disease, weakened immune system, cancer, or underlying conditions.

Symptoms are similar to influenza and include cough, shortness of breath, fever, muscle aches and headache. Symptoms usually begin within two to 14 days of exposure.

The Health Department encourages individuals who stayed at the Grand Islander and develop symptoms consistent with Legionella infection to seek medical attention and report the illness to DOH’s Disease Outbreak and Control Division Disease Reporting Line by phone at 808-586-4586. DOH said these individuals should get tested for COVID-19.