A MARTÍNEZ, HOST:
Milder winters in the Northeast are making deer ticks more active at a time when they're usually dormant. Experts are calling that a growing public health threat. Here's Connecticut Public Radio's Michayla Savitt.
MICHAYLA SAVITT, BYLINE: Deer ticks are tiny. They bite thousands of people every year in New England. The species can pass on Lyme disease and other sicknesses, which can be very serious. Dr. Toni Lyn Morelli is with the Northeast Climate Adaptation Science Center. While 40 degrees doesn't feel warm, she says that's when adult deer ticks will seek hosts in winter.
TONI LYN MORELLI: We can think about being careful when the kids go outside to check for ticks when they come back in in certain months of the year. It's becoming a year-round check-yourself-for-ticks situation.
SAVITT: The Connecticut Agricultural Experiment Station in New Haven helps people learn whether a deer tick bite gave them a disease. Entomology department head Dr. Goudarz Molaei says 275 tick samples have come in since December 1, much more than past winters. He opens one of the envelopes mailed into to the lab. Molaei pulls out a tick so swollen, it's almost unrecognizable. He says it might have fed for several days, making it more likely to transmit an infection.
GOUDARZ MOLAEI: This is a fully engorged tick. It's a tick of concern, and we will proceed with that.
SAVITT: Research technician Noelle Khalil tests to see if the adult female tick carried Lyme, anaplasmosis or another tick-borne disease. She mixes it with liquids in a vial, then shakes it to break up tissue before it goes in a centrifuge.
NOELLE KHALIL: It's going to spin all this debris you see to the bottom.
SAVITT: Results take a few days to come back after more steps and a PCR test. Centers for Disease Control data show Lyme disease rates have been steadily increasing in the U.S. New England states have seen the biggest increase of cases and overall rate of infection. Dr. Megan Linske is another scientist at the lab. She ties this to the warming climate.
MEGAN LINSKE: Everybody is looking for the scapegoat when it comes to vector-borne diseases and ticks and tick-borne diseases. And I think climate change is a big one.
SAVITT: New England temperatures are rising faster than the world average, and the largest temperature increases are happening during winter. Linske says that could lead to more native and non-native ticks.
LINSKE: And without that limiting factor of winter, we're going to see more of those pop up. And we're going to see more of them establish in the Northeast as well.
SAVITT: Chantal Foster is an avid hiker from central Connecticut and no stranger to ticks. Her dog has had Lyme disease before and recovered, but Foster hasn't had it. Just this February, she had to pick ticks off her dog after two hikes. She's careful that neither of them get bitten.
CHANTAL FOSTER: If you're just paying attention to what you're doing, you should be OK. That's not to say that it can't happen, but I'm not going to not go outside.
SAVITT: Dr. Linske with the tick lab says while they research how to manage tick populations, people in the Northeast must learn to coexist with them year-round. That includes avoiding brushy, wooded areas and tall grass and doing a full body check of people and pets after being outdoors. For NPR News, I'm Michayla Savitt in New Haven, Conn. Transcript provided by NPR, Copyright NPR.