Protection from Lyme disease can be as close as your pocket, thanks to an iPhone application developed by Yale researchers that tells people what to do if they’re bitten by a tick and how serious their risk is. 

The app uses global positioning system (GPS) technology, which tells users the prevalence of infected deer ticks at their location in the continental United States and provides a list of doctors in the area who treat Lyme disease. 

“It’s one of the first health apps with information that can affect people’s health directly and that’s geographically coordinated according to risk,” said Durland Fish, Ph.D., professor of epidemiology, who led the project. It was inspired by a disease outbreak app developed at the height of the 2009 swine flu epidemic by Fish’s former student, John Brownstein, Ph.D. ’04, who is now an instructor in health informatics at Harvard. 

The Lyme app was made in conjunction with the American Lyme Disease Foundation and the Centers for Disease Control and Prevention. The Yale team used 100 field researchers over four and a half years to draw up a map of tick prevalence around the country. Though the map is available on the Web, “it’s not geo-coordinated for where you are,” Fish said. “That’s important. There are a lot of areas in the country where there’s little risk. If you’re in Colorado, you get zero risk.” 

The app also gives tips on ways to prevent Lyme disease—avoid wooded areas and tuck pant legs into your socks. Another section, with both life-size images and enlargements, shows users how to identify ticks that cause Lyme disease (and some that don’t). It also includes verbal instructions and a video on how to remove a tick. 

Since Lyme infection depends on how long an attached tick has been feeding, users who have been bitten can compare the tick to life-size photos of the progression of blood engorgement, ranging from under an hour to 96 hours or more. The photos “are just blobs,” Fish admits, but that’s exactly how the engorged ticks appear on the body, so they’re “right on the money.” 

The app also lists the symptoms of Lyme disease and includes a dozen photos of the telltale rash that accompanies most cases. Again using GPS, the app provides directions to nearby doctors’ offices and a button to call them. 

A useful app “leverages what people want and need on the go as opposed to what they would do at their computer,” said Lilly Gold, co-founder of IntuApps, which developed it. The app is available from iTunes for $1.99; proceeds benefit the American Lyme Disease Foundation.