By Patricia Gay and David DesRoches

A new effort to battle Lyme disease in Weston could help to reduce the number of tick-borne illnesses in the area, but critics worry that the proposed pesticide could damage the environment. 

The Westport Weston Health District is seeking 130 households in Weston and Westport to participate in an experimental study that begins in May.

For this study, the health district is partnering with the Centers for Disease Control, which is funding it, and Yale University’s emerging infections program, which is monitoring the results.

The project calls for spraying a single application of the pesticide Talstar around the perimeter of a yard to see if it decreases the incidents of tick-borne illnesses. Half the yards in the study will be sprayed with the pesticide, while the others will be sprayed with plain water to avoid false positives.

After the pesticide is applied, surveys will be sent to each participant for four months to see if any ticks were found or if anyone in the household contracted a tick-borne illness.

In November, the health district will inform residents if their lawns received the pesticide or the water placebo. Participants will receive up to $40 in gift cards for their time.

Risks

However, there are certain risks associated with using Talstar. Its active chemical ingredient is bifenthrin, a synthetic pyrethroid insecticide that affects the nervous system of insects and is commonly used to kill termites.

Bifenthrin is designated as a class C carcinogen by the Environmental Protection Agency, meaning there is “suggestive evidence of carcinogenic potential.”

While no harm to people has been documented from bifenthrin, the EPA warns that it is highly toxic in aquatic environments — especially to fish.

Donald Weston, Ph.D., a toxicologist at University of California Berkeley, has studied pyrethroid pesticides since 2003, and documented significant risks associated with the pesticide.

“Bifenthrin is by far the most common contributor to aquatic toxicity,” Dr. Weston stated in an e-mail. “If there are compelling human health reasons to treat lawns, then I think that virtually any other pyrethroid would be preferable to bifenthrin in order to minimize environmental effects in nearby creeks and rivers.

However, Kristin Norlund of the Centers for Disease Control and Prevention said bifenthrin was chosen for the study after careful study and scientific review.

Between 23% and 44% of Connecticut households reported using pesticides to control ticks in their yard, according to a 2008 study.

“Given this widespread use, it is important to know whether pesticide use actually prevents human illness, and if so, how to minimize the amount of pesticide used. Lyme disease is an enormous public health problem in Connecticut and other states involved in this study. Tick-borne diseases are a serious problem and this sort of prevention research is more than warranted,” Ms. Norlund said in an e-mail.

The study’s coordinator, Julie Ray of Yale, said the topography and hydrology of each property in the study will be assessed before applying the pesticide, and no chemicals will be sprayed within 200 feet of a waterway. The chance of rain will also be considered because rainfall could cause runoff and subsequent water contamination.

“We really need to balance these risks,” Ms. Ray said. “I consider myself very environmentally conscious… I can’t think of another pesticide application that would be more targeted in terms of reducing tick-borne diseases.”

Dr. Weston contends that even if the study avoids areas with high runoff, it “may do little to limit contamination of waterways if the treated lawns are in neighborhoods served by storm sewers. Runoff from lawns will go through the storm drains and into the nearest waterway, though it may be quite distant from the treated properties.”

In addition to Weston, other towns in Connecticut participating in the study include Bethel, Bridgewater, New Fairfield, Newtown, Ridgefield, Roxbury, Westport and Wilton. Identical studies are being conducted in Maryland and New York.

Hyperendemic

Lyme disease was named after the town of Lyme, Conn., where a large number of cases were identified in 1975.

Lyme is transmitted to humans by the bite of infected ticks. Its symptoms can range from fever, chills and body aches, to joint swelling, weakness, severe fatigue, trouble concentrating and temporary paralysis. Some who have the disease may experience a bull’s-eye rash between three and 30 days after infection.

While Lyme is treatable with antibiotics if caught early, delayed or inadequate treatment may lead to serious and disabling conditions.

“Lyme disease is hyperendemic in this area and is one of the fastest-growing vector diseases,” said Dr. Steven Phillips, a Lyme disease specialist based in Georgetown. He said his practice is very busy and never slows down. “It’s a sad situation,” he said.

More than 4,000 cases of Lyme disease were reported in Connecticut in 2009, with nearly 700 of those incidents occurring in Fairfield County, according to the Connecticut Department of Public Health.

And, according to a 2008 report conducted by the University of New Haven, as much as 90% of adult ticks in the area may be infected with Lyme bacteria.

Mark Cooper, director of the Westport Weston Health District, said the long-term goal of the pesticide study is to offer the public “an efficient and safe way to reduce the likelihood of contracting Lyme disease.”

As a part of Yale’s emerging infections program, Associate Director James Meek anticipates a successful experiment. “We haven’t been able to show scientifically that different interventions can reduce the number of cases of Lyme disease. This may be one of the first to show that a particular intervention can reduce cases of Lyme disease. That would be fantastic,” he said.

Weston First Selectman Gayle Weinstein called Lyme disease “a huge issue in town.” She said if the study proved that Talstar eliminated ticks and was safe for pets and children, it was something the town should seriously consider.

Balancing the risks

The pesticide study may not be right for every home in Weston, Mr. Cooper said, especially those near waterways. “Properly used, the pesticide is supposed to be safe,” he said.

But in addition to snuffing out ticks, bifenthrin could also kill beneficial insects and contribute to the disappearance of honeybees, a condition known as colony collapse disorder.

A study published in the Environmental Toxicology and Chemistry Journal indicated that sublethal doses of bifenthrin “significantly reduced bee fecundity, decreased the rate at which bees develop to adulthood, and increased their immature periods… The impact of pesticides on the colony may be severe.”

Weston beekeeper Marina Marchese lamented that the pesticide treatment may hurt the propagation of her honeybees. She owns Red Bee Honey and is president of the Back Yard Beekeeper’s Association, one of the largest groups of its kind in the U.S.

“This is going to make my stomach turn,” Ms. Marchese said. “If this study by the health district commences, it will be a very sad for the 400-plus families who raise honeybees and the farmers and gardeners who rely on them here in Fairfield County and the vicinity.”

Mr. Cooper said if people don’t like the idea of pesticides, that’s fine, because the study is voluntary and will be limited to 130 households, half of which will get plain water instead of the pesticide.

“Of course we need to protect our water resources and water supplies,” said First Selectman Weinstein, but this is one case in which the town needs to weigh all the options. “There needs to be a balance,” she said.

Originally published in The Weston Forum