The study will determine whether two anti-tick interventions, used separately or together, can reduce Lyme disease at the neighborhood level. An ecologically sensitive approach will be used, taking into account the lifecycle of ticks and their interactions with the environment. Interventions will target feeding and questing ticks, with a focus on reducing ticks economically, in a way that is safe for people, pets, and the environment.
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 using an oil emulsion. Met52 kills ticks that are looking to feed.
Intervention #2: The Tick Control System, TCS®, is a small box that applies a low dose of fipronil, the insecticide in the popular pet product Frontline®, to small mammals as they feed on bait inside the box. Mice and chipmunks are largely responsible for infecting ticks with the Lyme bacterium. Once treated the ticks they carry die.
By targeting ticks, we anticipate that neighborhoods treated with Met52 and TCS interventions will experience reductions in tick numbers and fewer cases of tick-borne diseases.
The study will answer once and for all whether we can prevent cases of tick-borne disease by treating the areas around people's homes. If this approach prevents disease, we will be able to recommend plans that could be immediately adopted by local municipalities, governments, community groups, or neighborhoods.
Project assistants Samantha Calkins and Nicholas Jakubek collecting research samples on the Cary Institute campus.
Research will be conducted in a randomized, placebo-controlled study – the scientific gold standard. Treatments involve spraying Met52 and deploying TCS in residential areas. Participating neighborhoods will be randomly assigned one of four treatments: Met52 plus TCS; Met52 plus sham TCS; sham Met52 plus TCS; sham Met52 plus sham TCS. At the end of the study, participants will learn which treatment their property received.
Placebo controls (shams) are a critical part of well-designed scientific studies. The sham Met52 intervention involves spraying the base liquid, but without fungus spores; the sham TCS treatment applies a fipronil-free liquid to rodents.
Study participants will be asked to report diagnosed cases of tick-borne disease as well as encounters with ticks on people and pets. Field sampling and lab analyses will measure the number of ticks in each neighborhood and whether they are carrying pathogens.
This groundbreaking project will be 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.
The study will take five years to complete. In 2016, we are identifying study neighborhoods and recruiting people to participate in the study. We will also estimate the abundance of ticks in a sample of properties before we begin treating them. Tick-killing treatments will be deployed between 2017 and 2020. Impacts of the treatments on ticks and tick-borne diseases will be monitored during this time.
The study will take 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 will be recruited. Each neighborhood will consist of 6-10 square blocks and roughly 100 properties.
The selected study neighborhoods have been identified as hotspots for Lyme disease by the research team and their partners at the Dutchess County Department of Behavioral and Community Health.