New Tularemia Case Confirmed; Disease in Fifth Year on Island
By CHRIS BURRELL
For the fifth summer in a row, a rare and potentially fatal disease called tularemia continues to surface on the Vineyard.
State public health officials yesterday confirmed this year's first case of tularemia: a male landscaper from Edgartown who became ill in early June. Another landscaper from Edgartown is listed as a probable tularemia case, pending follow-up blood tests.
Both men are under 30 years of age and have undergone medical treatment for the disease, public health officials said.
This latest confirmed case brings the total tularemia count for the Vineyard to 27 people, all since the summer of 2000, when the disease infected 14 Islanders and killed one man from Chilmark who didn't seek treatment soon enough.
Tularemia typically strikes only one or two people a year across the state, but for the last five years, the disease has found an inexplicable niche on the Vineyard.
Medical researchers from the Massachusetts Department of Public Health (DPH), the federal Centers for Disease Control and Prevention (CDC) and both Harvard and Tufts universities have traveled to the Island numerous times searching for clues to the outbreak.
"Whatever the environmental source is hasn't gone away completely," Dr. Bela Matyas, the state medical director of epidemiology, told the Gazette.
After all the investigations and field research, one fact came into focus: Landscapers are at the highest risk for contracting tularemia on the Vineyard.
All but a handful of the 27 people infected worked outdoors, mowing lawns or cutting brush. And the majority of cases were also the pneumonic form of tularemia.
Public health investigators theorize that many of the victims inhaled airborne dust or dirt laced with the tularemia bacteria. That theory led them to issue public health advisories strongly urging landscapers to wear dust masks when they are working.
The masks should be rated between N95 and N99, said Donna Enos, the infectious disease nurse at the Martha's Vineyard Hospital.
Neither of the two men who became ill this year was wearing a dust mask, DPH officials said.
The advisories may have put a dent in the infection rate. In the first summer, 14 people fell ill with tularemia. By the summer of 2001, the number of people confirmed with the disease had fallen to five. There were three cases in 2002 and another three cases confirmed here in 2003.
Dr. Frederic Cantor, the state's public health veterinarian, said the cases of the two landscapers who became sick this year proves an important point: "People exposed to the aerosol are at risk even if they are young and healthy."
While the DPH wants to spread the word about tularemia infection among landscapers, the Island hospital is trying to reach a population that seems to dominate that trade - Brazilians.
Last Thursday, the Martha's Vineyard Hospital held a forum on tick-borne illnesses, specifically geared toward the Brazilian community. Only a half-dozen people showed up, but Ms. Enos plans to hold another forum in the winter.
Tularemia can also be spread to humans through a tick bite from a dog tick, which is larger than the deer tick responsible for the transmission of Lyme disease.
Tularemia symptoms resemble the flu and can include fever, swollen glands, sore joints, chest discomfort, vomiting and sore throat. Prompt medical treatment is key.
While the public health experts have focused their attention on prevention and immediate treatment for symptoms, they haven't been able to identify why tularemia seems to thrive on Martha's Vineyard.
No other place in the country has ever experienced an outbreak of pneumonic tularemia. The Vineyard has seen two outbreaks, the other one in 1978 when 15 people were infected, seven of them exposed to the bacteria in one cottage in Chilmark.
Tularemia bacteria is also considered one of the top bio-terrorist substances, and while no one ever suspected the Island outbreak as a case of terrorism, the fact seemed to spur some of the scientific interest.
Epidemic intelligence teams from the CDC's division of vector-borne infectious diseases in Fort Collins, Colo., have come here twice to collect air samples and dog ticks, trap skunks, rats and mice and draw blood samples from landscapers.
The lead CDC investigator, Katherine Feldman, who later published her findings in the New England Journal of Medicine, pointed out that tularemia organisms can survive for several weeks in water, soil and decaying animal carcasses.
But despite its legendary longevity, no scientist has yet explained why the disease goes dormant for years at a time, only to resurface again in similar geographic areas of the Vineyard.
"Tularemia is what we call a very focal disease," Sam Telford, a parasitologist from Tufts University, has told the Gazette. "It's not all over the Island. There are little hot spots here and there."
Katama in Edgartown and the Squibnocket area of Chilmark have already been identified as two hot spots, where several of the victims are thought to have been exposed. David Kurth, who died from tularemia in August 2000, had been mowing a lawn near Squibnocket about a week before he developed flulike symptoms.
"The Martha's Vineyard situation has many, many unanswered questions, the most basic of which is to understand the ecology of tularemia on the Vineyard," Dr. Feldman also told the Gazette. "I don't think we've been able to scratch the surface on that. We just don't understand how climate contributes to an increased number of cases in a certain summer."