(NEW YORK) — Tick populations could see a “boom” in traditionally cooler regions should global temperatures continue to rise, possibly increasing the likelihood of the spread of tick-borne diseases, according to new research.
Even with just a temperature increase of only 1 degree Celsius, regions that are typically cooler — such as Scotland, where the research was conducted — could see tick densities increase by 26% to 99% by 2080, according to a paper published in the Royal Society Journals on Tuesday.
Researchers built a mathematical model to predict how tick populations will change in time in response to changes in temperature, Rachel Norman, a professor at the University of Stirling in Scotland and author of the paper, told ABC News.
Included in the model are considerations for types of landscape and the availability for ticks to feed on a host between each of its life stages — egg, larvae and adult, allowing researchers to study the complicated interactions between the landscape, temperatures, the ticks and the hosts they’re feeding on, Norman said. Hosts are typically deer or small rodents but can also be birds, dogs and people.
As Scotland has warmed, ticks have moved further into the mountains and areas that they traditionally would not have been able to survive because temperatures in the past were too cold, Norman said, adding that ticks tend to thrive in wooded areas with undergrowth, should other conditions, like temperature and the availability of hosts, be present as well.
In some areas in Scotland, cooler temperatures are limiting tick populations. But in other regions that are now warm enough, tick populations can increase significantly because there are plenty of hosts for them to feed on, Norman said.
After the ticks feed on a host, they drop into undergrowth on the ground and molt into the next stage, which typically takes about a year in Scotland due to the cooler temperatures and therefore limits population increases, Norman said. But with warmer springs emerging earlier and warm temperatures lasting through fall, the ticks have a longer period of time in which they can emerge.
“They won’t emerge and start looking for food until we hit a particular temperature” — about 7 degrees centigrade or about 44 degrees Fahrenheit, she said.
The model could apply to other climates around the world as well, Norman said.
With booms in tick populations comes the potential for more people around the world to be exposed to tick-borne diseases, the researchers said.
The next step in the modeling will be to apply different diseases, such as Lyme, to study, the risk related to the density of tickets, Norman said.
Earth’s average global temperature has surpassed a 1-degree Celsius temperature rise since the late 1800s, with most land areas warming faster than most oceans, according to the Fifth National Climate Assessment, a definitive breakdown of the latest in climate science from 14 different federal agencies, including NOAA, NASA, the EPA, and the National Science. Foundation.
The planet is on the brink of a 1.5-degree Celsius rise in temperature, according to climate scientists.
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