Why you need to know about mice, ticks, warm temperatures and Lyme disease – Washington Post
A mother of seven, Wood tries to shrug off her tiny bedfellows. “It’s a common rural problem,” she says, although she admits that she has “never experienced anything like this in my own bed.”
The recent appearance of vermin and pests in Wood’s bedroom coincides with the warming temperatures related to climate change. The past three years have been the planet’s hottest on record, and it is in this changing climate that many pests thrive, negatively affecting human health.
Forty to 90 percent of white-footed mice carry Borrelia burgdorferi, the spirochete bacterium that causes Lyme disease, and they provide the first blood meals for blacklegged ticks, also known as deer ticks, which can transmit the disease to humans.
White-footed mice are typically considered outdoor animals. But in suburban and rural areas near forested land, they easily squeeze through cracks and holes the size of a dime and often nest inside walls and in garages.
Wood’s garage, which is built into a hillside amid old cow pastures that are being reclaimed by young forests, rests directly beneath her bedroom, and it’s not uncommon for her to hear the scratching of mice within the walls. Dozens of poppy-seed-size blacklegged tick nymphs could hitch a ride indoors on a single white-footed mouse, then find a blood meal on house mice, other rodents or even members of Wood’s family.
“We’re diligent about doing tick checks when we come in from outside,” Wood says, “but my son and one of our family dogs have had Lyme. It’s scary to think that mice might be bringing ticks inside my house.”
One hundred fifty miles south of Wood’s home, Peggy Siligato, co-owner of Narragansett Pest Control in Rhode Island, has seen more mice over the past five years than during the rest of her 40-year career. “Seventy-five percent of our business is mice,” she said, and it had increased about 25 percent “from what it used to be.”
Science is offering a possible explanation for what Siligato is witnessing: Warming temperatures and milder winters have increased not only the population of the white-footed mouse but also its range.Sheila Haddad, vice president of sales for Bell Laboratories, which manufactures rodent control technology, agrees: “Rodent pressure is increasing. Mice used to seasonally enter homes primarily in the fall and winter months in New England, but now it’s a year-round problem. Warmer winters mean that more mice survive; it never gets cold enough to kill them.”
Haddad said she has noticed the same kind of increase in mouse populations as Siligato. In Atlanta, for example, “there’s been an increase in reported venomous snakebites, which means that there are more snakes feeding on rodents.”
“Everything is changing year after year,” Haddad says. “Our rodenticide sales to distributors have increased about 15 percent over the past two years.”
Siligato adds: “West Nile virus has killed many birds of prey along the East Coast, meaning there are more mice. To say it’s just climate change isn’t exactly accurate, but it’s probably a part of the story.”
The Cary Institute of Ecosystem Studies, a research and education organization in New York’s Dutchess County, has predicted that there will be a rise in reported Lyme disease cases in 2017 along the Eastern Seaboard because there was a bumper crop of acorns in 2015. Acorns are a favorite food of the white-footed mouse, and the population of the species has been shown to increase two years after a surge of the nuts. More mice means more opportunities for tick nymphs to have their first blood meals.
Families such as the Woods, who have a large oak tree that may have dropped up to 10,000 acorns just 100 feet from their home last fall, might notice even more mice around or even inside their homes.