“There are things you can do to your property that we know will reduce the number of ticks,” says biologist Felicia Keesing. “But no one has really shown that you can treat your property in isolation and reduce your probability of getting Lyme disease.”
Recent studies suggest that piecemeal application of pesticides doesn’t work. Keesing references some recent research that showed that treatments on individual properties produced a reduction of the tick population within those areas by as much as 65 percent; but surprisingly, that reduction of ticks had no effect on the number of cases of Lyme disease that people there got. “So we throw around a number like 90 percent: What if we can reduce the number of ticks by 90 percent? Maybe that will be enough.”
And to do that, treating an entire neighborhood may be the answer. “My yard isn’t an island,” says Keesing. “So if I just treat my yard, I could still have lots of ticks imported from other properties by wildlife and my pets. By treating the whole neighborhood, we could reduce the total number of ticks in my yard and my neighbors’ yards. It makes the whole neighborhood safer.”
More than 300,000 people every year are diagnosed with Lyme disease in the US. Tickborne illness has steadily increased in range and intensity since the 1970s, when the connection between ticks and disease was first made. Lyme disease diagnosis and treatment remain complicated, and there is currently no vaccine available. In the Northeast, the blacklegged ticks that carry Lyme also transmit babesiosis, anaplasmosis and Borrelia miyamotoi. Co-infections are common. Protecting public health hinges on minimizing encounters with infected ticks.
Targeting ticks at the neighborhood level will be the focus of the Tick Project, a rigorous five-year study to be conducted by the Cary Institute of Ecosystem Studies in Millbrook in partnership with Bard College. The project will be carried out in collaboration with the US Centers for Disease Control and Prevention, the New York State Department of Health and the Dutchess County Department of Behavioral and Community Health.
The study will be led by Bard’s Felicia Keesing – David and Rosalie Rose Distinguished Professor of Science, Mathematics and Computing – and Cary Institute disease ecologist Richard Ostfeld. Both are experts in the effects of ecosystems on disease: Ostfeld specializes in research on West Nile virus and Lyme disease, and Keesing’s disease research has focused on three tickborne diseases: Lyme disease, anaplasmosis and babesiosis.
The Tick Project will take place in Dutchess County, home to one of the nation’s highest Lyme disease infection rates. Residents of 24 neighborhoods will be recruited from Lyme disease hotspots identified by the researchers and their partners at the Dutchess County Department of Health. Each neighborhood in the study will consist of six to ten square blocks and roughly 100 properties. Interventions will target feeding and questing ticks using two commercially available products. The study will determine whether the two tick-control methods, used separately or together, can reduce the number of cases of Lyme disease at the neighborhood level.
One of the products, Met52 fungal spray, contains the spores of a fungus, Metarhizium anisopliae, that occurs naturally in forest soils in eastern North America and has been shown to kill ticks. Met52 has been developed as a commercial product to be applied with a high-pressure sprayer on vegetation, where it kills ticks looking for hosts on which to feed. “It can reduce tick numbers quite a lot,” says Keesing. “The spores of the fungus attach to the tick and grow into it. And this strain of the fungus has been developed to target ticks and not to harm beneficial arthropods like bees and ants.”
The other product is a bait box. The “Tick Control System” or TCS is a small box that attracts rodents with food. When an animal enters the box, it receives a low dose of fipronil, the active ingredient in many flea and tick treatments used on dogs and cats (including Frontline). The rodent passes through a little tunnel that coats it with insecticide that kills ticks, but the small mammal itself doesn’t get harmed, says Keesing. In fact, it’s helped, because it gets a little bit of food and it gets its ticks removed. The bait box is constructed so that it targets the particular creatures that they want to affect, but keeps the pesticide away from all the rest. The amount of fipronil in the bait boxes is approximately ten times less than that in products such as Frontline, she adds, “so if you’re willing to put it on your pets, you should have no problem with these bait boxes.”
This will be the first study using the neighborhood approach. The treatments to be used were chosen because of clear evidence that they have significant potential to reduce tick numbers, says Keesing. The interventions are economically feasible, environmentally sensitive and commercially available, so that the results can be easily duplicated by property-owners should the study prove successful. “There are treatments out there in various stages of development, but it’s not clear that they’ll ever come to market. We chose deliberately to use treatments that we were sure could be something someone could use on their property, if this study is fruitful. We’re trying to make this study as practical as possible.”
If this approach prevents disease, researchers will be able to recommend plans that could be immediately adopted by local municipalities, governments, community groups or neighborhoods.
The Tick Project is made possible by a $5 million grant from the Steven & Alexandra Cohen Foundation. The project is estimated to require $8.8 million in funding, so further fundraising is necessary. “The Foundation gave us a wonderful starting gift,” says Keesing, “but we’re confident that with so many people in this area concerned about Lyme disease and wanting to make a real difference, there are enough people invested in resolving this issue.”
And if this study doesn’t work, she adds, “I think we have to take a whole different look, because we’re really throwing everything we have at this problem now with this study. This is the study we’ve always wanted to do. This is the one that everyone has said, ‘If we could really do it right, this is what we would do.’ So this is the time; let’s all pitch in and get this study done right, and then we’ll have an answer once and for all.”
For more information, visit www.tickproject.org.
