Those spring snowflakes prolonged the arrival of tick season, but by Memorial Day weekend, Stillwater resident Brian Lindvall was already plucking a pair of the bloodsucking pests off his dog.
Local experts said this year’s late freeze helped align the populations of wood and black-legged ticks to peak at the same time, making matters worse in the already high-risk area of Washington County for tick-borne illnesses.
Minnesotans have been diagnosed with tick-borne illnesses at record rates since 2007 with more than 1,000 cases of Lyme disease found each year.
Janet Jarnefeld, the Metropolitan Mosquito Control District’s (MMCD) tick specialist, said between 20 and 30 percent of black-legged ticks, or deer ticks, can transmit disease and Minnesotans should take all preventive measures due to this year’s abnormality.
“The ticks are looking like they are fiercer than in a normal year because you’re seeing peaks of both [wood and deer ticks] at the same time,” Jarnefeld said.
Washington County as a whole is a high-risk area for Lyme disease, a potentially serious bacterial infection, because more people live in wooded areas where deer tick population is dense and popular hosts like rodents and birds are prevalent.
State Department of Health statistics show that from 1986 to 2010, nearly 15,000 cases of tick-borne diseases were reported in the state, most involved Lyme disease. Reports of tick-borne diseases started to rise in the early 2000s and have not shown any signs of slowing.
In June 2011, the Health Department reported the first known death in Minnesota from the tick-borne Powassan virus that can cause encephalitis or meningitis. Also in 2011, record numbers of Minnesotans fell sick from two less common tick-borne illnesses, babesiosis and human anaplasmosis.
“The highest population of deer ticks in the area is northern Anoka County and Washington County,” said Marty Kirkman, east region group leader at the MMCD, which monitors tick populations year-round.
Kirkman added that ticks typically aren’t affected by the weather; but 18 inches of April snow delayed wood ticks, which typically peak in April, to simultaneously grow and feed with their smaller cohorts, deer ticks, which peak in May.
“It’s so hard to see them, you just have to keep an eye out,” Lindvall said.
Ticks have normally found their home in the east metro. But that’s changing, Jarnefeld said, as warmer winters have allowed them to migrate.
Andrew Krammer is a Twin Cities freelancer.