Ticks have a thing for Mary Ritter, but the sentiment is unrequited.
She takes a summer hike, she gets ticks. She takes a winter hike and picks off ticks. She steps outside her Greensburg townhouse, goes back in and finds ticks.
"I must be some kind of tick magnet," she said. "I'd like to know if I have the wrong blood type or put out some pheromone or something that attracts them."
Growing up in the woods and fields as a Michigan tomboy, she never had ticks, she said. Not until she moved to Pennsylvania. Now, she gives ticks a free ride and a warm meal. Fortunately, they have never given Ms. Ritter a disease.
"They just love me," she said. "I can't stand the little buggers."
The little bugs — arachnids, actually, from the spider family — generally grow to less than 1/8 inch, but they're having a growing impact on people. The science is divided on why some tick species are particularly drawn to some humans. Among the leading theories are that it has something to do with volume of carbon dioxide exhaled, desirability of blood type (in order of tick interest A, O, AB, B), radiant heat detected or all of the above.
Just as they somehow find Ms. Ritter, ticks are finding more people than ever. Nationwide and in Pennsylvania, tick populations are growing and cases of tick-related illnesses are rising. A new generation of diseases, still rare but more virulent than the familiar tick-borne pathogens, are drawing arachnid researchers to spots in Pennsylvania where more ticks carry very dangerous disease than in any other location in the country. The U.S. Centers for Disease Control and Prevention said the burgeoning tick-vectored diseases should be considered "threatening."
"Tick-borne diseases increasingly threaten the health of people in the United States," the CDC said in a statement. "Improved understanding about reported tick-borne illnesses, expanding geographic ranges for ticks, and risk factors will help prevent and control tick-borne disease."
Blame the weather, and COVID
Tick populations and the severity of tick attacks are generally determined by weather, ecological impacts on tick habitat and human behavior. Ticks survive winter by going dormant, latching onto a warm host or hiding in leaf litter. In Pennsylvania, warm, wet spring weather increased the abundance of wild plant life in 2020 and 2021. More food made it easy for bird and mammal mamas to reach top carrying capacity, as many gave birth to as many offspring as their bodies could produce. All that food increased the first-year survival of mammal and bird babies, creating an expanding smorgasbord for blood-sucking ticks. During the COVID-19 shutdowns of those years, Pennsylvanians discovered the outdoors were always open, giving ticks a plentiful bipedal target.