State Health Officials Document Increase in Tick-Borne Illnesses

By BRIEN HEFLER

Massachusetts public health officials have confirmed eight cases of tularemia on the Island this year, the highest number since 2000, when 15 people were diagnosed. The report raises the number of confirmed tularemia cases to 37 since the summer of 2000 and marks the sixth successive summer that the rare disease has been documented on the Island.

Dr. Frederic Cantor, the public health veterinarian for the state department of public health (DPH), said three of the eight cases have been confirmed as pneumonic tularemia, a form of the disease that affects the respiratory tract and is caused by inhaling airborne tularemia particles. While rare in other parts of the nation, pneumonic tularemia has been documented in increasing numbers on the Vineyard in recent years. Health officials continue to urge people who work outdoors to wear respirators rated at N-95 or higher to filter out potentially harmful particles. Dr. Cantor said none of the three victims of pneumonic tularemia appeared to be wearing masks when they were infected.

"Most of these again seem to have exposure to outdoor activities in terms of landscaping, caretaking and gardening. I think part of the issue is, are all these people not wearing masks and why?" he said. "That seems to be a risk factor and most of the people seem not to be wearing masks."

He also cautioned that masks might be ineffective for men with beards.

"If someone has a beard, you won't have a good fit, you'll be wearing a respirator for your beard," he said.

Dr. Cantor said the DPH is examining a possible four additional cases of tularemia. At least two of this year's confirmed cases were other types of tularemia, which can be spread by handling infected material, such as animal carcasses or by bites from dog ticks, known to carry the disease. Three of the eight cases are still unclassified, Dr. Cantor said. One has been confirmed as tick borne, and the first case of the year, contracted in April by a Vineyard landscaper, was oropharyngeal, indicating that the affected glands were in the man's throat. While the pneumonic form of tularemia is the most common type seen on the Island, Dr. Cantor said the other cases this year point to the fact that the disease can be spread a variety of ways.

"What the cases say is that there are multiple ways people can get tick-borne illnesses," Dr. Cantor said, "We're trying to do what we can to raise awareness of the risk."

Health officials caution people who believe they may have been exposed to seek immediate medical treatment if any symptoms appear including fever, sore joints and throat, swollen glands and chest pain.

Tularemia has been documented on the Island since the 1930s, when some hunters began contracting the disease, also sometimes known as rabbit fever because rabbits primarily carry the disease. The first major outbreak of pneumonic tularemia occurred in 1978, when 15 people were infected, seven of them from one home in Chilmark. A Chilmark man died in the summer of 2000 after contracting the disease.

Tularemia usually affects about 200 people a year nationwide, putting the Island at the foreground for study in the medical community. Since the first outbreak in 1978, the high number of tularemia cases have baffled public health officials and fueled numerous studies. Researchers first traveled to the Island after the 2000 outbreak, including investigators from the Centers for Disease Control (CDC), the DPH and Harvard and Tufts universities. The teams concluded that landscapers were most at risk, but so far they have been unable to conclusively locate areas where the risk for tularemia is the greatest.

"There is work that's still being done on the Island," Dr. Cantor said, "There may be areas that are likely hot spots but we can't really ascertain that."

Sam Telford, an associate professor of infectious diseases at Tufts University, has been coming to the Island since 2000 once a month during the spring and summer to collect dog ticks and examine the wild animal population as part of a tularemia study. Mr. Telford told the Gazette in June that the number of infected dog ticks has remained the same in the last two years. Mr. Telford's study shows that Squibnocket and Katama have higher rates of infected ticks than other parts of the Island.

Island health officials say the incidence of tick-borne illness in general has been higher than usual this year. Donna Enos, the infection control nurse at the Martha's Vineyard Hospital said she has confirmed at least 50 cases of tick-borne illnesses since April and is investigating at least 50 more. Lyme disease tops the list and one case of Rocky Mountain spotted fever has been confirmed. Mrs. Enos believes the number of tularemia cases seen this year may in the end the record of 15 set in 2000.

"Ultimately, by the time we have the cases confirmed, we are going to see that," Mrs. Enos said, "I've seen more [cases] than I've seen in a long time come through my desk in lab results. I truly believe the numbers are higher in comparison to other seasons."

The reason is unclear, but Mrs. Enos said she believes people are spending more time outdoors this summer because the weather has been hot and sunny.

Dr. Timothy Tsai, director of emergency services for the hospital agreed. He said the hospital emergency room has seen a higher number of patients complaining of tick-borne illness symptoms. Dr. Tsai said the hospital this year began a panel that tests for four of the most common tick diseases and is now offering precautionary antibiotics to patients.

"Some patients are very concerned and they want the protection, so we will offer antibiotics on a short term course," he said.

He also cautioned people to be extra vigilant and to see a doctor or go to the emergency room if symptoms appear. Blood tests are not always certain and can be negative at first and later turn up positive results.

Dr. Cantor and state health officials have been working with Island veterinarians to collect blood samples from animals. Dr. Cantor said about 12 per cent of animals tested show evidence of having contact with tularemia. Dr. Michelle Gerhard Jasny, a veterinarian participating in the study, said the information could some day be used to study where tularemia is most common and provide insight into how immune systems battle the disease.

Many of the animals that tested positive for tularemia did not necessarily have the disease. Why some animals, like dogs, are less susceptible to contracting tularemia is one of the issues being studied.

A Providence, R.I., pharmaceutical company is studying tularemia cases on the Island as part of a program to create a vaccine against the disease. EpiVax, Inc. was awarded an $831,000 small business grant as part of a federal counter-terrorism initiative to develop a vaccine against Tularemia, which is ranked as one of the top five bio-terrorism agents. The company is taking blood samples from Island residents who have contracted tularemia in the past to study antibodies as part of the first phase of the program.