Lyme Disease and Invasive Diseases: Disease Containment in Northeast

Blacklegged ticks, the insects that carry the bacteria that causes Lyme disease, seem to be travelers. They're now flourishing in areas once thought to be tick-free, and Lyme disease cases are on the rise in areas historically free of Lyme. Recent years have seen a dramatic increase in diagnoses. In Pennsylvania, for example, diagnoses rose 25 percent between 2013 and 2014. Nationwide, the disease affects 300,000 people every year.

Researchers from the University of Pennsylvania, New York Department of Health, and State University of New York at Albany feel it's important to look at how easily the vectors of the disease are moving, and they recently published findings in the journal Evolution, regarding the origin and recent migratory history of recently discovered tick populations in certain areas of the Northeastern United States.

In their research, the scientists used genetic and phylogeographic analyses, learning that the ticks moved into new areas from established populations-mainly through short-distance, local moves, according to a release.

Their phylogeographic analysis indicates that ticks mainly moved north to south or south to north between neighboring locations, with occasional long-distance movements, according to the release.

The researchers noted that the reason for the population expansion remains unclear. Possibly the ticks are adapting to new local environments, or changes in land use and climate make new environments more suitable for them, according to a release.

While more work remains to be done to understand what is driving the movement and expansion of ticks, knowing more about their migrations could help inform efforts to protect the public from Lyme disease, according to the release.

"From a control perspective, if you know they are moving extremely easily, you could control them in your backyard but they might be back in a week," Khatchikian said, according to this release. "If we want to reduce tick populations over the long term, this means we have to start thinking about more sophisticated approaches."