New deer feeders will begin treating white-tailed deer for ticks in four Howard County parks as part of a five-year study by the U.S. Department of Agriculture's Agricultural Research Service and University of Maryland to combat the state's tick population and Lyme disease cases.
This week, the county's Department of Recreation and Parks placed treatment devices, called 4-poster feeders, at Blandair Regional and Cedar Lane parks in Columbia, Rockburn Branch Park in Elkridge and David Force Natural Resource Area in Ellicott City.
Parks were chosen based on tracking data of the county's deer and mice populations via GPS collars. Tracking for each began in January and September, respectively.
Tick Management Project coordinator Andrew Li, an entomologist with ARS Invasive Insect Bio-control and Behavior in Beltsville, said he and his team fitted about 30 does and 10 bucks with collars that ping their location every hour for one to two years. Feeders were placed in parks near residential neighborhoods, said Kim Kaplan, ARS chief of special projects, with each one covering a 50-acre range.
"We know from past studies that the 4-posters have effectively reduced the number of deer ticks," Li said.
Four feeders were placed in Blandair Regional Park, two feeders in Cedar Lane Park, nine feeders at Rockburn Branch Park and five feeders at David Force Natural Resource Area.
Kaplan said as deer eat the corn dispensed into feeder troughs, paint rollers apply Tickicide chemical solution to their ears and neck. ARS technicians will monitor feeders on a weekly basis, add corn and Tickicide and handle maintenance.
Li is a lead developer of the 4-poster feeder produced by C.R. Daniels, a diversified manufacturer based in Ellicott City. Andy Szulinski, a member of the company's sales and marketing team, said the list price for each feeder is $519, or $469 if purchased in bulk.
The department has used 4-poster feeders for tick treatment in the past decade, but Kaplan said feeder placement was based on intuition or where hunters spotted deer rather than tracking.
"We collared deer to figure out exactly where they go and how they moved from the parks to people's yards," Kaplan said. "The deer move out of the parks through people's yards and ticks drop off. All of a sudden, we have these ticks in close proximity to where people are."
Philip Norman, deer project manager for the Department of Recreation & Parks, said wildlife populations fluctuate, declining after changes in weather, disease, hunting and vehicle collisions. The department's winter 2017 survey showed an average density of 61 deer per square mile across 11 square miles.
Based on data, Norman said, the 251-square mile county indicated a deer population of a little more than 15,000.
"Howard County isn't an island, so deer can come or go at any moment, changing the actual population," Norman said. "I'm fairly comfortable with that number as a ballpark figure, but that isn't to say I know that to be the actual population."
Dawn Gundersen-Rindal, an ARS research leader and molecular biologist, said ticks move from rodents to deer when they become adults. Rodents are the source of a bacterial pathogen that causes Lyme disease, she said, which is transmitted from tick bites.
"There are essentially pools of medical problems that people are getting that are not being easily, readily or accurately diagnosed," including Lyme disease, Gundersen-Rindal said. "My opinion is ticks that carry the Lyme disease pathogen are under-studied and under-researched. We need more federal research support for those."
According to the Center for Disease Control and Prevention, headaches, fatigue and muscle and joint aches are a few early symptoms of Lyme disease. If undiagnosed, more severe health problems may occur, such as facial paralysis, brain and spinal cord inflammation and nerve pain.
The likelihood of people contracting Lyme disease is highest between May and August. The CDC reported 1,867 confirmed and probable Lyme disease cases in Maryland in 2016, up from 1,727 the prior year. County numbers, however, declined from 195 cases to 134 in that same period. County numbers peaked at 369 cases in 2008. That year, the state reported 2,220 cases.
By contrast, Montgomery County had a state-high 280 cases in 2015 and 309 in 2016. Baltimore County had 218 cases in 2015 and 191 in 2016. About 59 probable and confirmed cases were reported in Prince George's County in 2016, according to state data, a slight increase from the prior year.
There were 28,450 confirmed cases nationwide in 2015.
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Gundersen-Rindal said ARS screens ticks for 10 pathogens – three viral and seven bacterial – the latter of which are more prevalent in Maryland.
"Viral pathogens are primarily associated with Connecticut and New York – areas where there are extremely high incidences of Lyme disease," she said. "We haven't found a tick yet with the viral pathogens in Maryland."
Lisa de Hernandez, a spokeswoman for the county's health department, said people are usually tested and treated for Lyme disease by their primary care physician, urgent care centers or hospital emergency departments.
"If their symptoms are neurological, they can be referred to a neurologist for further evaluation," Hernandez said. "We collect the data on Lyme since it is a reportable disease, [but] we do not treat patients here."