Answer Woman: How is climate change affecting tick populations?
Today's question is about critters that are pretty much universally hated: ticks. Got a question for Answer Man or Answer Woman? Email Executive Editor Karen Chávez at [email protected], and your question could appear in an upcoming column.
Question: I am an avid hiker. In past years in February, you had to be careful on the trails because of ice. With global warming that's not the case anymore. I'm hiking in short sleeves in February. I met my first wood tick of the year. I never had that happen in February. With the rising temperatures what impact is this going to have on the wood tick population? Also, with temperatures increasing, are there insects that might be migrating further north that in terms of disease represent some form of danger to those of us who are out and about?
Answer: In short, there is ample proof at this point that climate change is already having an impact on not only populations of many tick species but on numbers of other pests like mosquitos.
However, the factors that are contributing to these increased populations are more complex than just warmer temperatures and changes in weather.
What impact will climate change have on tick populations?
Director of Graduate Programs in Entomology at North Carolina State University Michael Reiskind told the Citizen Times that climate change has certainly contributed to the issue, but differently, than you might assume.
“Without any doubt, tick populations have increased in the United States,” said Reiskind. “But primarily due to changes in land use. If you consider changes in land use an element of climate change, then there is no doubt that climate change has affected tick populations. If on the other hand, you want to restrict your understanding of climate change to the general increase in temperature that is clearly being experienced globally, it's a little bit harder to make the connection.”
Reiskind also cited the steadily increasing populations of deer and other mammals as a factor that strongly corresponds with the increase in ticks.
“With the ticks in general, and tick-borne disease, and then Lyme disease in particular, it's really driven in large part by the mammal hosts of the ticks,” said Reiskind.
The CDC backs this idea with information on its website, though it specifically attributes the increase in mammal populations and corresponding tick populations to the warming climate.
"The development and survival of ticks, their animal hosts (such as deer), and the bacterium that causes Lyme disease are all strongly influenced by climatic factors, especially temperature, precipitation, and humidity," stated the website.
While Reiskind mentioned that many species of ticks are capable of surviving and even remaining active in the winter regardless of climate change, NCSU Professor of Entomology Charles Apperson said that we may see an increase in this activity as global temperatures increase.
“Stages of some tick species that normally overwinter in a dormant state will continue to be active for a longer period of time into the colder months,” Apperson said in an email to the Citizen Times.
He also said that the activity period for some agricultural pests will be expanded as the earth continues to warm.
Many states are now conducting their own surveillance on ticks and tick-borne illnesses to help get more clarity on this subject — N.C. included. The North Carolina Division of Public Health’s communicable disease branch has asked veterinarians in several counties throughout the state to send in ticks collected from animals with the goal of creating a map to show the diversity and distribution of the insects.
Are there insects that might be migrating farther north that in terms of disease represent some form of danger to those of us who are out and about?
According to the CDC website, the organization has scientists conducting studies on the impact of climate change on the general spread of infectious diseases, notably including Lyme disease and West Nile virus disease which are both carried by mosquitos.
Reiskind also spoke to the potential dangers of mosquito-borne illnesses, though he wanted to remind readers that their presence is something the U.S. is used to, at this point.
“The tiger mosquito is the biggest potential threat,” said Reiskind. “But it's been here now for a good 30 — we're working on almost 40 years now. And so that's not new for anybody.”
Reiskind also said that NCSU has been looking into Japanese bush mosquito populations as they increase in the U.S., but according to their findings, these species are likely to be more sensitive to increased temperatures than mosquitoes that are native to N.C.
The experts agree that tick populations are increasing. Asheville residents should make every effort to protect themselves against tick-borne illnesses, and regardless of which of the complex factors are in play, it’s probably a good idea to stay aware of the possibility of tick bites no matter what season you’re getting outdoors.
Take a look at Apperson’s information on ticks to learn how to best guard against these illnesses, or visit the CDC’s informative website at cdc.gov/ticks, which gives tips on how to avoid getting tick bites and what to do if you get one.
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Iris Seaton is a news intern for the Asheville Citizen Times, part of the USA TODAY Network. Please support local, daily journalism with a subscription to the Citizen Times.
This article originally appeared on Asheville Citizen Times: Answer Woman: How is climate change affecting tick populations?