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Lyme disease: Researchers testing anti-tick vaccine on mice. Could it help?


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Pennsylvania college is hosting a first-of-its-kind tick mitigation study in an effort to turn ths tide against Lyme disease.

East Stroudsburg University and Allegheny College are partnering on the $1 million research project.

The study will deliver an anti-tick vaccine to mice in six counties through food pellets, explained Nicole Chinnici, director of the Pennsylvania Tick Research Lab at ESU. The feeders are designed to be inaccessible to larger animals.

The white-footed mouse, which can be found throughout the Northeast, is a “reservoir host” that transmits various pathogens to ticks, Chinnici said.

“Everything that we’ve seen in the lab research has indicated that this vaccine’s very effective at reducing the ticks, especially ticks that are feeding on mice populations, so this study will give us a better understanding of how this works in the environment and how Pennsylvania can move towards a treatment strategy that’s effective,” she said.

A few states have conducted similar studies with a vaccine specific to Lyme disease, Chinnici said, but this is the first broader mouse vaccination study in the wild, and the first tick mitigation study at all in Pennsylvania.

Based on the lifespans of ticks and mice, results could become apparent around the third year of the study.

“In order for us to really see a reduction in an area, we would have to get through a couple generations, so that the treatment is really saturating the environment in terms of exposure of mice, if the mice are able to pass the ability on to their litters and things like that,” she said.

Feeders will be placed at 12 locations each in Bucks, Lehigh, Monroe, and Pike counties in eastern Pennsylvania, as well as Crawford and Mercer counties (part of Brooks’ district) in western Pennsylvania.

“We’ll also be looking at doing some acaricidal sprays that specifically focus on tick populations, and then looking at combinations of different integrated pest management strategies to see if we can determine the best strategy for Pennsylvania to reduce tick populations over time,” Chinnici said.

Lyme disease and tick-borne illnesses

For six straight years — 2013 through 2018, the most recent year for which the Centers for Disease Control and Prevention has full data — Pennsylvania has reported more Lyme disease cases than any other state. (Pennsylvania also led in 2019, though the CDC notes that data may be incomplete due to COVID-19.) It was last surpassed by Massachusetts, which reported about 100 more cases than Pennsylvania in 2012.

Levels have fluctuated in other mid-Atlantic states such as New Jersey during the same period, but none have experienced the same sharp rise as Pennsylvania.

In 2018, confirmed and probable cases totaled 10,208 in Pennsylvania, as well as 4,000 in New Jersey, 3,638 in New York, 520 in Delaware, 1,382 in Maryland and 1,139 in Virginia. These six states accounted for more than 60% of reported Lyme disease cases in the nation.

Lyme disease can cause stiffness, joint pain and short-term memory problems, among other symptoms, according to the Pennsylvania Department of Health.

“Most people treated with antibiotics, especially those treated early, fully recover from Lyme diseases,” according to the DOH, though about 20% of people have persistent symptoms.

Almost 31% of all Pennsylvania ticks tested by the lab at ESU have been infected with at least one pathogen. Lyme disease is particularly prevalent, having been found in one-third of 42,800 deer ticks.

With three years of testing completed, “one of the most notable things that we’re seeing are changes in co-infections,” Chinnici said. It’s becoming more common for ticks to carry multiple pathogens, such as Lyme disease and human variant anaplasmosis.

Early anaplasmosis symptoms include fever, chills, severe headache, muscle aches, nausea, vomiting, diarrhea and loss of appetite, according to the CDC.

“Rarely, if treatment is delayed or if there are other medical conditions present, anaplasmosis can cause severe illness,” such as respiratory failure, or death, the CDC said.

Tick prevention

Hikers should walk in the middle of paths, not through tall grass. The Pennsylvania Department of Health advises using products with 0.5% permethrin to treat clothing and gear.

“Wear light-colored long pants, long sleeved shirts and closely knitted socks,” Pocono Record columnist Debbie Kulick advised hikers earlier this spring. “Tuck shirts into pants and tuck pants into socks.”

Check yourself, your clothing and your gear for ticks after coming inside. If you do find a tick, pull it out with tweezers.

“Use fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible. Pull upward with steady, even pressure. Don’t twist or turn the tick, this can cause the mouth parts to break off and remain in the skin,” Kulick said.