EYDER PERALTA, HOST:
New data from the CDC suggest ticks are spreading farther than their normal regions in the U.S., and experts are worried that could also mean an increase in tick-borne illnesses like Lyme disease. Joining us now to explain more is Nicole Baumgarth. She's a professor of infectious diseases and director of Johns Hopkins University's Lyme and Tick-Borne Disease Research and Education Institute. Professor, thank you for being here.
NICOLE BAUMGARTH: Yeah. Thanks for having me.
PERALTA: How are tick-related incidents tracked?
BAUMGARTH: They are usually tracked by the health departments. So every state department has a requirement for most tick-borne illnesses to be reported. So if you go to a local GP's office, if you have a tick-borne illness such as Lyme disease, your health professionals are supposed to report it to the health department. And they will collate the data and then send it to the Centers for Disease Control.
PERALTA: And so the CDC reported an overall increase in incidents, but now things look more stable. Still, as we said, ticks seem to be spreading beyond where they are typically found this time of year. Any idea why?
BAUMGARTH: So we have seen over the last three decades an increasing spread of ticks. This has to do with climate change. As the climate, in particular in the northern hemisphere, is warming, ticks can spread more north. So, for example, 20 years ago, there were really no overwintering ticks in the south of Canada. Now we have endemic populations of ticks, and they can transmit Lyme disease there. We also live closer to areas where ticks like to live. And we have a loss of biodiversity, meaning certain species that ticks like to feed on, such as deer and the white-footed mouse in the Northeastern United States, have expanded. And therefore the ability for ticks to eat more, and therefore they will expand as a population.
PERALTA: So, Professor, I mean, I think the thing that most worry about is Lyme disease because, you know, it can cause fever and paralysis among other things. What do we know about its prevalence in the U.S. and globally?
BAUMGARTH: The prevalence of Lyme disease is also on the rise, just as the population of ticks are increasing. In the U.S., we are now seeing - I mean, estimates are about 476,000 cases per year of Lyme disease. And it's really important to point out that these numbers are really likely incorrect because if you live in an area where there's a lot of Lyme disease going on, usually the doctor doesn't bother anymore to send this information to the CDC, so there are way less reported cases than we know are happening.
PERALTA: What are you going to be looking for in the coming months to assess how much of a problem ticks will be in the future?
BAUMGARTH: Yeah. We are particular worried about another tick species - as if we don't have enough with the Ixodes ticks, the black-legged tick that causes Lyme disease - and that is the Amblyomma tick, or the lone star tick. These are very aggressive ticks, even though they're very small. We have seen them expanding geographically. And what we're worried about with this tick is that they are likely the cause of Alpha-gal syndrome, this red meat allergy. And so we are looking at that as a sort of indicator of the tick population expanding and this Amblyomma tick population getting a foothold and taking over.
PERALTA: That's Nicole Baumgarth. She's a professor of infectious diseases at Johns Hopkins University. Professor, thank you for talking with me.
BAUMGARTH: Thank you very much.
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