The Eco-epidemiology lab at Columbia University, headed by Maria Diuk-Wasser, has been working on Block Island since 2010, investigating the links between the island’s environment, animal host populations, and human cases of tick-borne diseases, including Lyme disease and human babesiosis. During the extensive field work that takes place every spring and summer since 2010, our field crew collect ticks and trap small mammals to better understand the ecological factors that contribute to the incidence of these diseases and assess the public health risk to residents. For this reason, we have also been working closely with Dr. Peter Krause and colleagues from Yale University, who have been leading a serosurveillance program on tick-borne diseases on Block Island since 1991 and consists of bi-annual serosurveys wherein residents who spent at least one month during the transmission season (May through October) on the Island may be tested for Lyme disease and babesiosis at no cost.
Ticks have 3 stages which emerge and are active at different times of the year: larvae, nymphs and adult ticks. They all need to take a blood meal to molt into the next stage and female ticks need it to lay eggs. The stage that represent the most risk to people are the nymphs, which can be infected after feeding on an infected animal as larva, and are most active from May to July. The nymphs densities on Block Island have range from 170 to 410 nymphs per hectare, in our sampling sites between 2010-2016. The infection rate has ranged between 11% and 29% during the same time period. Bi-annual serosurveys (spring and fall) that were conducted on Block Island, found that Lyme disease prevalence fluctuated between 8.4% and 29.1% and human babesiosis have fluctuated between 0.5% and 10%.
As part of our research we are most interested to understand better how, where and under which circumstances are people most at risk of encountering ticks. Although trivial, our understanding is very limited because our information is anecdotal and because not many studies have addressed how people’s activities and preventing measures affect their risk, and how it changes with past tick encounters and more knowledge about ticks and the diseases they can carry. One of the limitations to understand this are the methods that have been used to gather this information. Traditionally, this information has been collected by questionnaires at the end of the high risk season or at one point in time, so we don’t have sufficient information to relate tick exposure to different activity patterns. How people are exposed to ticks is a key piece of information to understand how different interventions to reduce the tick burden will impact on human health.
For this reason and to gather more detailed data, we have developed a smartphone application to collect data through simple and fast surveys with a citizen science approach: The Tick App. Through the app we also provide resources to learn more about the biology and ecology of ticks, how to identify them and how to protect yourself from ticks. You can send us a picture of the tick and help us monitor the tick population and the different tick species found on Staten Island. For non-app users, you can sign up on our website www.thetickapp.org to receive the surveys by email or download a paper survey package to complete and mail back to us. We are only asking people to complete one tick diary a day for 15 days, during that time we will ask if you found any ticks that day, what did you do (from a list of activities) and if you used any preventing measures. The app is available at the app store or google play.
As part of the study, we are offering free Lyme disease and Babesiosis testing before and after the study as part of a collaboration with Dr. Peter Krause from Yale University. This information will be matched to the information from the app and it will help us better understand which areas on the island are most risky and how to better protect people from tick bites, with science-based interventions that are tailored to the island.