The Tick Project is a five-year study is testing whether neighborhood-based prevention can reduce human exposure to Lyme disease and other tick-borne diseases. The methods we tested are simple and safe for people, pets, and the environment.
Who is conducting the research?
The project is led by Cary Institute disease ecologist Dr. Richard Ostfeld and Bard College biologist Dr. Felicia Keesing, in partnership 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.
Where IS the study takING place?
The study is taking place in Dutchess County, New York, which is home to some of the nation’s highest rates of Lyme disease incidence. Residents of twenty-four neighborhoods were recruited. Each neighborhood consists of 6-10 square blocks and roughly 100 properties.
How were the study sites chosen?
The selected study neighborhoods were identified as hotspots for Lyme disease by the research team and their partners at the Dutchess County Department of Behavioral and Community Health.
WHERE DOES FUNDING FOR THE TICK PROJECT COME FROM?
A generous gift from the Steven & Alexandra Cohen Foundation provided the core funding for the project. Many individual and institutions have also provided financial support. The total cost of this effort is $8.8 million dollars. The Cary Institute of Ecosystem Studies is leading a campaign to raise the additional funds needed to support this project.
What is the study testing?
The study is designed to determine whether two tick control interventions, used separately or together, can reduce the number of cases of Lyme disease at the neighborhood level. The interventions target feeding and questing ticks, with a focus on reducing the number of ticks safely and economically.
Intervention #1: Metarhizium anisopliae is a tick-killing fungus that occurs naturally in forest soils in eastern North America. A strain of this fungus, Met52®, has been developed as a commercial product. It can be sprayed on low vegetation where it kills host-seeking (“questing”) ticks.
Intervention #2: The “Tick Control System”, or TCS®, is a small, baited box that attracts small mammals. When an animal enters the box, it receives a small dose of fipronil, the active ingredient in many tick treatments used on dogs and cats. Fipronil kills ticks on treated animals such as mice and chipmunks, which are largely responsible for infecting ticks with the Lyme bacterium.
How is the research being done?
The research is being conducted as a randomized, placebo-controlled study – the scientific gold standard. Every property in the study received Tick Control System (TCS)® bait boxes and Met52® spray, but in some neighborhoods, the bait boxes and spray did not contain the active ingredients. Inactive TCS® bait boxes look the same as the active boxes, but they do not contain the chemical that kills ticks. Inactive Met52® spray is just water that does not contain the fungal spores.
The neighborhoods were divided into four groups, each of which got one of these combinations of spray and bait boxes:
Active Met52® spray and active TCS® bait boxes
Active Met52® spray and inactive TCS® bait boxes
Inactive Met52® spray (water!) and active TCS® bait boxes
Inactive Met52® spray (water!) and inactive TCS® bait boxes
All of the participating properties in a neighborhood received the same treatment. We asked study participants to report diagnosed cases of tick-borne disease as well as encounters with ticks on people and pets. We also sampled ticks on properties and conducted lab analyses to measure the number of ticks in each neighborhood and whether they were carrying pathogens.
The study has taken five years to complete. In 2016, we identified study neighborhoods, recruited participants, and estimated the abundance of ticks in a sample of properties before we began treating them. The tick-killing treatments themselves were deployed between 2017 and 2020. Impacts of the treatments on ticks and tick-borne diseases have been monitored during this time, and we are currently analyzing the results.
What will you do with the results?
If the approaches we tested were successful in preventing Lyme disease, we will be able to recommend concrete strategies that could be adopted by local municipalities, governments, community groups, or neighborhoods.
why did you pick these particular methods of tick control?
We chose methods of tick control that have been shown to be safe for pets, people, and the environment, and that have also been shown to be effective at killing ticks in people's yards. We only considered methods that were already commercially available to avoid any delays in applying useful results from this study to the real world.
What is Met52® and how does it work?
Met52® fungal spray consists of spores of the fungus Metarhizium anisopliae mixed with water. Metarhizium anisopliae occurs naturally in forest soils. The Met52® spray has been found to kill ticks and agricultural pests such as certain beetles and root weevils. The spray is applied to plants and the surrounding soil. When a tick comes in contact with the fungal spores, the spores stick to the tick. When the spores sprout, the fungus grows through the tick’s outer covering, killing the tick. Ticks are usually killed within 3 to 7 days of exposure to Met52® spores.
The fungus in the Met52® spray is Metarhizium anisopliae, which occurs naturally in soils around the world. Met52® is non-toxic for infants, children, and adults, and for dogs, cats, and other mammals. The Environmental Protection Agency has determined that no harm will be caused by people eating, breathing in, or touching things containing Met52®. No toxicity or harmful effects were seen when Met52® was tested in laboratory animals. The Environmental Protection Agency has approved its use in residential areas as a bioinsecticide.
How does the bait box (or TCS®) work?
The bait box is a child-resistant box containing a non-toxic bait block that attracts rodents (mice and chipmunks). Rodents (mice and chipmunks) that enter the box to feed or investigate are treated with fipronil, which is the same chemical used on pet products. This pesticide kills the ticks on the rodent and any ticks that come into contact with the animal for the next several weeks. This interrupts the transmission cycle of Lyme disease. In this study, half of the homes received active bait boxes containing fipronil, and half received inactive bait boxes without the pesticide.
The fipronil bait boxes have the potential to reduce Lyme disease in people by reducing the abundance of infected ticks. Most ticks become infected with the Lyme disease bacterium by feeding on small mammals such as white-footed mice, chipmunks, and shrews.
The chemical used in the bait boxes is fipronil, which is the active ingredient in many popular topical flea and tick control products (e.g. Frontline ®) for household pets. The concentration of fipronil in the bait boxes is 10 times lower than that found in topical flea and tick control products (Frontline ®) used on household pets. The likelihood of coming into direct contact with the wick containing this low concentration of fipronil is low, because it is encased in a child-resistant box.
The chemical is also safe for predators. A predator would have to consume ~600,000 mice that had been treated with fipronil to experience even a mild effect from the chemical.
Does anyone conducting the research have a financial interest in the outcome?