With six confirmed cases of tularemia and reports of Lyme disease coming in, the Vineyard has begun another season of documenting tick-borne illnesses.

Although cases are still being confirmed, official numbers will not be released until early next year. But initial reports from state public health officials and the Martha’s Vineyard Hospital indicate no slowdown in the high rates of tick-borne illnesses on Island.

“The pattern we’ve seen is consistent,” said Dr. Bela Matyas, medical director of epidemiology at the Massachusetts Department of Health. The department confirms all cases of tick-borne illnesses diagnosed in the state.

“What we can’t say from looking at the statistics to date is whether the rates of disease will be higher,” Dr. Matyas said.

This week, Donna Enos, infections control nurse at the hospital, confirmed six cases of tularemia, a bacterial illness carried by deer ticks. Two additional cases are still awaiting confirmation. By the end of July last year, eight cases of tularemia had been confirmed on the Island.

So far this summer, cases of tularemia have been diagnosed both at the hospital and at Island Health Care, a walk-in medical clinic in Edgartown.

Dr. Matyas said a wide spectrum of people are affected. “They’ve been of both genders and range in age from the very young to considerably older. Not all of them are year-round Islanders and at least several of the confirmed cases have been landscapers,” he said.

Nancy Phillips, nurse practitioner at Island Health Care where four cases of tularemia were diagnosed in the past three weeks, said she diagnosed three male landscapers and one female not in the landscaping business. Their ages ranged from 22 to 61 and all were Vineyard residents.

“Everyone’s been treated, everyone’s fine,” Mrs. Enos said.

The disease is treated with antibiotics.

There are six varieties of tularemia. The most common form, ulceroglandular, represents 75 per cent of all cases. Other types include glandular and typhoidal. One of the more rare forms nationally is pneumonic, a respiratory strain.

For reasons that are not fully known, the Vineyard is a hot spot for pneumonic tularemia.

Landscapers are believed to be most at risk, because it is thought that mowing may release bacteria into the air from carcasses of dead rabbits, which are carriers. Tularemia is also sometimes called rabbit fever.

“Between 2000 and 2006, there were 60 reported cases of confirmed or probable tularemia on Martha’s Vineyard. Two-thirds to three-quarters of those were pneumonic,” Dr. Matyas said.

“Almost all the cases of pneumonic tularemia which have occurred in the last decade have been on the Island,” he said. “We’ve had scattered cases on the Cape and on Nantucket, but in the past 10 years, the very vast majority have been on the Vineyard. That really sets Martha’s Vineyard apart from the rest of the world, not just the rest of the country.”

The trend may also be reversing.

“We tend to see more pneumonic diagnoses, but this year, we are seeing a bit more glandular cases than pneumonic,” Mrs. Enos said.

Dr. Matyas said between 120 and 150 tularemia cases are reported each year nationwide. The vast majority occur in four south central states: Missouri, Kansas, Arkansas and Oklahoma.

The tularemia outbreak on the Vineyard began with 15 cases in 2000. One was fatal. Prior to that outbreak, the state saw an average of three cases a year. A previous outbreak occurred on the Vineyard in 1978 when 15 people were infected, seven of them from one home in Chilmark. Newspaper accounts from that time describe what was termed the curious Chilmark Mystery Disease.

The Island is the only place in the country ever to experience an outbreak of pneumonic tularemia, and following the 2000 outbreak, researchers from the Centers for Disease Control, the Massachusetts Department of Health and Harvard and Tufts universities traveled here to study the cause. The research concluded that landscapers were most at risk for the disease and that the south shore of the Island has higher rates of infected ticks than other parts of the Vineyard. Beyond that, much of the cause remains a mystery.

“The outbreak continues unabated, so we are trying to understand why that is, why it doesn’t go away,” said Sam Telford, associate professor of biomedical sciences and infectious diseases at Tufts Cummings School of Veterinary Medicine, this week. A leading expert in researching tick diseases, Dr. Telford was part of the team who visited the Vineyard in 2000.

Symptoms of tularemia include fever, lethargy, inflamation of the face and eyes and swollen glands.

“It’s difficult to diagnose because it can be like a summer flu,” Mrs. Phillips said.

“Many of the patients coming in with summer fevers end up with a diagnosis of a tick-borne illness,” said Dr. Timothy Tsai, director of emergency services at the Vineyard hospital.

Both the state health department and Island health care providers disseminate educational material on tick-borne illnesses with preventative tips to landscaping companies and to patients. They also hold forums every year.

“We tell them to walk a field before landscaping and to remove any animal carcasses so you don’t mow them over. Wear a mask when working and practice general tick prevention,” Dr. Matyas said.

“The real value is in educating people about the importance of coming in early to be evaluated,” Dr. Tsai said.

Educational materials also have been translated into Portuguese.

“It is probably fair to say that the Brazilian population is highly represented in the landscaping trades, so they are more at risk,” Dr. Tsai said. “More and more of them, thankfully, are coming in earlier and earlier for testing.”

Because tularemia is so prevalent on the Island, doctors are quick to make a diagnosis and begin treatment. “The health care provider community is really on the lookout. They are among the best in the world at picking up respiratory cases because they’ve been doing it for a number of years now,” Dr. Matyas said.

Doctors in other parts of the country may not be so attuned.

“For tick-borne illnesses generally, it’s a harder diagnosis to make in nonresidents who are going home to doctors who aren’t necessarily thinking tularemia,” Dr. Matyas said. “It’s probably true that we miss some cases because of it. People on the Island have the advantage of their doctors thinking of these symptoms.”

Tularemia is the only tick-borne illness for which the state records the numbers as they come in.

Cases of Lyme disease, Rocky Mountain spotted fever, babesiosis, ehrlichiosis and other tick-borne diseases are not tallied until the end of the calendar year.

As a result — and also because many people may delay seeking treatment — the early numbers are not necessarily a hard indicator.

For the month of June, Mrs. Enos said 39 cases of Lyme disease were reported on the Vineyard. That number has not been confirmed by the state and reports are still being recorded. Last year, the hospital reported 37 diagnoses of Lyme disease in June and 72 cases in July.

“These numbers, in my opinion, are in no way rock-solid numbers. I am sure the numbers are much higher. It’s just not possible to know about all the cases,” Mrs. Enos said.

Mrs. Enos confirmed there have been cases of babesiosis, but she said the numbers were not ready to be released. The same is true for ehrlichiosis. Last year, there were three confirmed cases of babesiosis in June and nine in July. Two cases of ehrlichiosis were confirmed in June of last year. “We’re seeing all the tick-borne illnesses,” Mrs. Enos said.

With multiple illnesses come co-infected patients as well, although Mrs. Enos said this trend is not new. “You do see combinations, but it’s not a lot of them,” she said. “It happens every year.”