Health officials say they may never know what caused the Legionnaires’ disease outbreak last month that killed a Levittown man and sickened nine others.
None of the water samples taken in the Levittown-Wantagh area tested positive for the bacteria Legionella, which causes the disease, said Mary Ellen Laurain, spokeswoman for the Nassau Health Department.
All 10 cases, which were of people who lived within a half-mile of Wantagh Avenue and Old Jerusalem Road, were confirmed the week of Oct. 10.
"We haven’t seen any additional cases, thankfully," and with the weather turning colder, no more are expected, so the source of the outbreak may remain a mystery, she said.
Legionella grows best in warm water, according to the Centers for Disease Control and Prevention. Most cases typically are in the summer and early fall, the CDC says.
John Liljehult, 96, died of the disease on Oct. 14. Two others on his block on Haven Lane also were hospitalized, but survived, as did six others.
The state has had 493 Legionella cases so far this year, and four deaths, including Liljehult’s, but there only have been eight clusters of cases involving two or more people, state Health Department spokesman Jeffrey Hammond said. In none of the clusters was the source determined, he said.
The disease is typically contracted by breathing in a mist or vapor containing Legionella, and it is not spread person to person, according to the Health Department.
A leading expert on Legionnaires’ disease, Jane Stout, president of Pittsburgh-based Special Pathogens Laboratory, which focuses on Legionnaires’, said the most likely explanation for the outbreak is bacteria that traveled in a mist from a poorly maintained cooling tower. Such mists can travel as far as a mile, research has found, she said.
Nassau County collected multiple samples from each of seven locations, Hammond said. The state’s Wadsworth Center Laboratory in Albany then tested the samples, he said. It typically takes more than a week to grow and identify the bacteria in the lab, he said.
Laurain said water samples were taken from cooling towers — equipment used in central air conditioning and the source of some past Legionnaires’ outbreaks — and residences, although "we’re not releasing how many residences and which locations."
Asked why samples were taken from some, but not all, residences of those sickened, Laurain said, "I’m not going to get into what [locations] we chose and how we did it. That was up to the professionals in our environmental health division."
Liljehult’s daughter, Krista Crockford, said gathering samples from seven locations "is totally not enough. You have three people right here on Haven Lane. If they had said they tested 50 places, then I’d say they did their due diligence."
Crockford accused the Nassau Health Department of not acting with enough urgency. Crockford, who lived with her father and tested negative for the bacteria, said county employees took samples from her home, but not until Oct. 16, two days after her father died, after others were hospitalized with the disease and after she had disinfected the shower head and faucet aerators, as a doctor had recommended. The bacteria can grow in shower heads and faucets, according to the CDC.
Laurain said "it takes some time to determine there’s a cluster" and the Health Department "immediately" notified the public on Oct. 14, when it became clear there were multiple cases.