A new study suggests that changing climate patterns may be altering the life cycles of blacklegged ticks in the northeastern United States, which could increase transmission among animals – and ultimately humans – of certain pathogens, including the bacterium that causes Lyme disease. Other colder regions of the country that have sufficient populations of blacklegged ticks – particularly Wisconsin and Minnesota – may also experience a higher risk of Lyme disease. However, the changing life cycles of the ticks may result in a less-likely probability of transmitting a more deadly pathogen that results in Powassan encephalitis, the researchers say.
A new study suggests that changing climate patterns may be altering the life cycles of blacklegged ticks in the northeastern United States, which could increase transmission among animals – and ultimately humans – of certain pathogens, including the bacterium that causes Lyme disease.
Other colder regions of the country that have sufficient populations of blacklegged ticks – particularly Wisconsin and Minnesota – may also experience a higher risk of Lyme disease. However, the changing life cycles of the ticks may result in a less-likely probability of transmitting a more deadly pathogen that results in Powassan encephalitis, the researchers say.
Results of the research are being published this week in a special issue of Philosophical Transactions of the Royal Society B dedicated to climate change and vector-borne diseases.
A team of scientists led by Taal Levi of Oregon State University and Richard Ostfeld of the Cary Institute of Ecosystem Studies analyzed 19 years of data on blacklegged ticks in the Northeast and their relationship to “host” animals ranging from small rodents to deer and other larger mammals. They then overlaid the results with climate data and used computer models to predict what may happen in the future.
“The bottom line is that as the climate warms, it is pushing the timing of tick nymphs and larvae forward, potentially changing the interactions they have with their hosts,” said Levi, an assistant professor in OSU’s Department of Fisheries and Wildlife in the College of Agricultural Sciences and lead author on the study.
“October is a key month,” he added, “because the difference between a cold fall and a warmer fall can have a profound effect on when the ticks interact with their hosts.”
Blacklegged ticks can be found in hardwood forests all along the eastern seaboard as well as in the northern states. They have a two-year life cycle that goes from eggs, to larva, to nymphs to adults.
After adult ticks lay eggs in the spring, the larvae emerge in the summer and in August and September they begin looking for a host to feed upon – usually mice, voles and other small rodents. They are not born infected with pathogens, but can become infected after feeding upon an infected host. However, their feeding lasts only a few days and they then become inactive and thus are not a threat to humans or large mammals at this stage.
Continue reading at Oregon State University.
Tick image via Shutterstock.
