The Vineyard's first tularemia case of the year, a 50-year-old male landscaper, may have contracted the potentially fatal disease after handling a dead rabbit he found while working in Edgartown, state public health officials said this week.
The latest case, which was confirmed last month, is also notable because health officials have determined that it was an oropharyngeal brand of tularemia, indicating that the affected glands were in the man's throat.
All but seven of the 30 cases confirmed on the Island since the outbreak began in the summer of 2000 have been the pneumonic form, leading medical investigators to advance the theory that people have inhaled airborne particles contaminated with the tularemia bacteria.
Epidemiologists at the state department of public health (DPH) now believe that the latest victim also inhaled the bacteria.
"The most likely explanation for his exposure is that he inhaled coarse particles as opposed to fine, and they didn't make it into his lungs," said Dr. Bela Matyas, the medical director of the epidemiology program at the DPH in Boston.
Nearly all the victims of the tularemia outbreak have been landscapers or people who worked predominantly outdoors. The outbreak claimed the life of one victim, killing a 43-year-old Chilmark man in August of 2000. He was known to have mowed a lawn near Squibnocket shortly before he fell ill with flu-like symptoms.
Tularemia is a powerful but rare bacterial disease. Rabbits are the most common carriers in addition to rodents such as squirrels, voles and muskrats, but a bite from a dog tick is the most typical way the disease is transmitted to people.
On the Vineyard, though, the pneumonic cases have dominated, making the Island the only place in the United States to experience an outbreak of pneumonic tularemia.
Dr. Matyas was skeptical yesterday that this year's case of oropharyngeal tularemia was contracted by ingesting any of the bacteria.
"He could have handled that rabbit and then handled food," said Dr. Matyas. "But maybe he raised up some dirt when he picked up a dead rabbit."
This week, the Edgartown landscaper talked to the Gazette and explained that he was taking care of a property in April on the western edge of Edgartown when he saw the rabbit carcass. The man, who had only recently moved to the Vineyard, asked to remain unnamed.
"I was cleaning up perennial beds and dividing ornamental grass," he said. "Off in a corner one morning was a rabbit [carcass]. I wasn't aware of the risks so I grabbed it and threw it away."
He recalled that there were rabbit droppings around the site where he found the remains. The animal appeared to have been killed and partially eaten by a hawk.
Within five days, he was sick. "I fit smoothly into that three to five day incubation period," he said. "I had a monster headache and swollen glands in the neck. I thought maybe I had the flu."
Then came the fever. "It was almost to 105. I was just shaking," he said.
He went to the Martha's Vineyard Hospital on a Thursday night for treatment and was given oral antibiotics. No better by Friday, he returned to the hospital and was admitted for five days of intravenous antibiotic treatment.
"They were pumping it into me as fast as they could," he said.
After about three weeks, he was feeling good enough to start working again.
Meanwhile, state officials at the DPH said there are no other confirmed or probable cases of tularemia on the Island that they are investigating.
They have analyzed about a dozen blood samples from landscapers on the Vineyard who have been sick, possibly with tularemia, but only the one so far has turned up positive for the disease. Tularemia affects only about 200 people a year nationwide.
"At the same time, we're very happy that specimens are being sent," said Dr. Matyas.
Alfred DeMaria, the director of communicable disease control at the DPH, said doctors are treating landscapers who become sick with antibiotics before there is concrete evidence of tularemia infection.
"People at high risk who come in with symptoms, we're treating them. Most of the time we want to avoid antibiotic, but we want people to be overtreated for it," said Dr. DeMaria.
The outbreak of tularemia on the Vineyard has attracted national attention, not only because of the singularity of such an event in the medical annals, but also because the bacteria is ranked as one of the top five bioterrorist agents.
Three times in the last five years, the federal Centers for Disease Control dispatched epidemic intelligence teams to the Vineyard from its infectious disease facility in Fort Collins, Colo., to study the outbreak and unlock the riddle of why such a rare disease is flourishing here.
They came up with solid answers and concluded simply that the landscapers were at the highest risk and would be advised to wear dust masks as a measure of protection from inhaling tularemia bacteria.
Last year, with the help of the Bush administration's efforts to combat terrorism, a Providence, R.I., biotechnology firm landed a $831,000 grant from the National Institutes for Health (NIH) to begin development of a tularemia vaccine.
Scientists from the company, EpiVax, Inc., came to the Island last winter to recruit people who have had the disease to participate in the research project and consent to a drawing of blood samples. That vaccine could take two to three years to develop.
Back on the Vineyard, landscapers have learned to be vigilant. Not all wear dust masks, but they know the symptoms. Landscaper Tristan Israel, who is also a Tisbury selectman, is one of the 30 people who has contracted the disease during this outbreak.
He is convinced one of his former employees may become the second confirmed case of this year. "He had that pounding headache. I'm sure it was tularemia. It came on a few days after he was mowing a lawn in Cow Bay [Edgartown]," said Mr. Israel.
The Katama area of Edgartown and the Squibnocket region in Chilmark have been identified by researchers as hot spots for tularemia.