While most people are familiar with Lyme disease, scientists over the past 50 years have detected "at least a dozen" new tick-borne diseases in the United States, including the deadly Powassan virus, Micaeleen Doucleff and Jane Greenhalgh report for NPR's "Goats and Soda."
The uptick in tick-borne pathogens in the United States aligns with a general upswing of infectious diseases around the world, Doucleff and Greenhalgh write. They explain that over the past six decades, the number of new diseases identified every decade has quadrupled—and the number of disease outbreaks occurring annually has more than tripled since 1980.
And when it comes to tick-borne pathogens, Felicia Keesing, an ecologist at Bard College, put it like this: "The more we look, in a sense, the more we find."
Some of the more recently discovered tick-borne diseases in the United States include:
- Anaplasmosis, babesiosis, and a bacterium that Keesing said is similar to Lyme, located in the Northeast;
- Ehrlichiosis, present across large parts of the country;
- Heartland virus, in the Midwest;
- Southern tick-associated rash illness (pathogen unknown), in the South;
- A new type of spotted fever in the west; and
- Powassan virus, in the East Coast and Upper Midwest.
While most of these diseases are relatively uncommon, one—the Powassan virus—is "especially worrying," Keesing said. Powassan attacks the brain, causing it to swell and is deadly in about 10 percent of cases. For those who are diagnosed with Powassan and recover, there is about a 50 percent chance of permanent neurological damage, Doucleff and Greenhalgh write.
The virus, which was discovered in 1958 in Ontario, Canada, now infects about seven people per year in the United States.
The 'secret weapon' against ticks? Mice, researchers say
There are several ways for humans to protect against tick-borne diseases—by wearing long sleeves, spraying on DEET, and examining yourself at night—but defending entire communities, such as a town or neighborhood, is more challenging, Keesing said.
Researchers believe mice could be a "secret weapon" on this front, Doucleff and Greenhalgh write. Rick Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies, has observed that mice are covered in ticks. While other animals groom ticks off, mice do not.
Based on his observations, Ostfeld thought he could turn mice into "little assassins," by covering them with insecticide—the same chemical that people use on their dogs and cats. "It's an even tinier drop," Ostfeld said, "So a little bit goes a long way."
Ostfeld and Keesing are testing the strategy, which involves trapping mice in a box that swipes them with the insecticide, in an experiment involving 1,200 families in upstate New York. As part of the five-year project, some families will get the mice boxes placed in their yards, others will have a fungus that's known to kill ticks sprayed on their shrubbery, and some families will receive neither intervention.
The researchers are optimistic about the results, Doucleff and Greenhalgh write. As Keesing put it, "If anything is going to work to reduce the number of tick-borne disease cases in neighborhoods, this is going to be it" (Doucleff/Greenhalgh, "Goats and Soda," NPR, 3/11).
Learn how to measure your return on population health innovation
Across any risk-based contract, tracking changes in a population’s per member per month (PMPM) spend is one industry standard to measure the impact of an organization’s investments. However, the time needed for a new intervention to ramp up makes it difficult to reduce actual PMPM spending and achieve cost savings in the early years of a new initiative.
Join us to review our methodology for analyzing the return on population health investments under risk-based payment, and then apply these skills using Population Health Advisor's newest tool: the Population Health Intervention ROI Estimator tool.