A physician who inspected the cruise ship Horizon, now in dry dock in Baltimore, says the ship's three whirlpool spas deserve "high consideration" as suspects in an outbreak of Legionnaires' disease that may have killed a Long Island man and sickened 29 others.
Dr. Joseph Plouffe of Ohio State University, who was hired to advise the ship's owners during the investigation, said that, while it is too early to identify positively the source of the infections, the disease has spread in the past through hot tubs and spas at resorts.
"One of the things about hot tubs is that the normal mechanisms you use in water to control bacteria, such as adding chlorine, aren't as effective," said Dr. Plouffe, who toured the Horizon last Saturday at Bethlehem Steel Co.'s Sparrows Point shipyard. "Also, Legionella likes warmer temperatures."
Bob Howard, a spokesman for the U.S. Centers for Disease Control and Prevention in Atlanta, which is investigating the outbreak, called the spa theory "absolutely unconfirmed and unsubstantiated."
There are many potential sources of the sometimes fatal respiratory illness, he said, and none has been ruled out. "We do not have the scientific proof we need at this point."
But Jim Grossman, a spokesman for Celebrity Cruise Lines, said the Horizon's spas were closed at the recommendation of the Centers for Disease Control before the ship's latest cruise, which began July 16. "The CDC said one thing you can do is turn them off," Mr. Grossman said.
So far, there have been six confirmed cases of Legionnaires' disease and 24 suspected cases among former passengers of the cruise ship. All were from New York and New Jersey, and all sailed between June 25 and July 16.
One former Horizon passenger, Pasquale Cantone, 68, of West Babylon, N.Y., died July 22 in a hospital on Long Island. An autopsy is expected to determine if he had the disease.
The ship was in Bermuda last week when laboratory tests of samples from its water system showed the presence of Legionella DNA -- though no live virus. Celebrity officials flushed the ship's water system with highly chlorinated water, flew more than 1,200 passengers home and sent the ship to Baltimore for further tests and routine repairs.
Centers for Disease Control officials and Dr. Plouffe said that the chlorination probably wiped out the bacterium and that the ship's 675 crew members, most of them still living aboard the vessel here, are in no danger.
Investigators are in New York, New Jersey and Connecticut interviewing former passengers and their families. The probe could take several months, Mr. Howard said.