Here & Now

UW Entomologist Updates on New Lone Star Tick in Wisconsin

Frederica Freyberg:

Now to health news. Wisconsin has another bacteria-filled tick pulling up to the human dinner table. This one is named the Lone Star tick, after the distinctive white blotch on the insect’s back. A bite from a Lone Star can transmit bacteria that can give humans a range of illnesses, some very serious. A new arrival from the south, it’s been found so far in six southern Wisconsin counties, including Sauk County, where UW-Madison entomologist Susan Paskewitz found one on her own daughter. Thanks for being here to talk to us about this tick. So you definitely confirmed that this was a Lone Star tick because you found it yourself.

Susan Paskewitz:

I did. And that wasn’t the first time this summer either. I was really surprised. I was up in Price County doing some work related to lyme disease and deer ticks and I’m out in the middle of nowhere in the swamp. I put down my blanket, which we use to drag across the vegetation to look for the deer ticks, and I picked it up and the first thing on that was a Lone Star tick.

Frederica Freyberg:

How widespread do you believe this tick is in Wisconsin right now?

Susan Paskewitz:

My own sampling would suggest pretty widespread. Just I’ve gotten it in two or three different places in the southern part of the state, as well as Price. And then we have a number of good reports from citizens who either send us the tick or they send us good pictures and we can tell. I think now, probably any place where habitat is appropriate, you could find Lone Stars.

Frederica Freyberg:

Do these travel from the south? They hitch a ride on animals or people?

Susan Paskewitz:

That’s what we thought was go on, and that seems really reasonable. We would have very sporadic, kind of one of two a year, ticks come into the entomology department here at UW. And, yep, they’re Lone Stars. But usually people had a travel history. Maybe they’d gone south for the winter and come back, and the tick had come off their dog or off their person.

Frederica Freyberg:

Let’s take a look at what this tick looks like. We're talking an awful lot about it, but we should show people what this tick looks like. We do have photos. So this is a Lone Star tick, and it is described because of that blotch right in the middle, correct?

Susan Paskewitz:

That’s right. That very condensed spot that you see on the adult female there. The other one that has a little bit of white markings kind of around the back edge of the body is an adult male Lone Star tick.

Frederica Freyberg:

So these ticks carry a pathogen that make people sick. What does it give them potentially?

Susan Paskewitz:

Yes. One of the things that’s associated with Lone Star ticks is a pathogen, Ehrlichia Chaffeensis, that gives people a disease called Ehrlichiosis. Unfortunately, this one is fatal about 2% of the time, so it’s really important that people get to the doctor if they come up with those summer flu kind of symptoms with fever and chills and muscle aches.

Frederica Freyberg:

All right. And so let’s take a look then at the more usual type of ticks that we see in Wisconsin, which is the deer tick and the wood tick. And, you know, some might say, you look at that wood tick and it has that white blotch. But the Lone Star is much more distinctive because it’s in the middle?

Susan Paskewitz:

That’s right. It’s a much more condensed spot, a little shiny spot, and it’s also a little bit rounder of a body shape on that wood tick that you're looking at there. You see that it's kind the whole upper quadrant of the body. At least on the female, it's got a lot of white. The male on the bottom there has the white much more distributed throughout the body.

Frederica Freyberg:

But generally it’s the deer tick that is known for potentially giving people lyme disease.

Susan Paskewitz:

Absolutely. That’s absolutely right.

Frederica Freyberg:

And how often does that occur? How often, if someone gets bit by a deer tick, do they develop lyme disease?

Susan Paskewitz:

So our studies are really focused on that kind of question, and we do a lot of sampling and collecting of ticks, and then diagnosing the pathogens they’re carrying. We find that throughout most of Wisconsin about 22% of the nymphal stage is infected with the lyme disease pathogen. Probably 45%, 50% of the adults are infected with that pathogen. The number of times that a person who's bitten by an infected tick actually ends up getting infected and sick is probably going to be high, 70% to 80% of the time, I imagine.

Frederica Freyberg:

So what do people do if they find a deer tick on their body or even in their clothes? Should they rush off and get prophylactic antibiotics or what?

Susan Paskewitz:

Yeah, actually, the recommendation from the Infectious Disease Society of America is that if you have a tick that’s been embedded, so actively feeding on you for at least 24 to 36 hours, that you go and get treatment with a prophylactic antibiotic.

Frederica Freyberg:

There’s another photo that we wanted to show and that is the deer tick, and I think it’s the deer tick and the wood tick side by side. We have that, and then we have the smaller baby versions of these ticks. And you’re saying that actually when they’re small, they’re dangerous because you might not see them right away.

Susan Paskewitz:

That’s correct. And if we have the picture coming up here, there’s the deer tick. You notice the two bigger ticks are the adult female and male. They’re big enough so if you have them on your person, you are probably going to feel them and remove them. But now on the bottom there you see two stages, the nymph and the larvae. The little, tiny larvae is not a risk because it's not infected. But the next stage up, the nymph, that’s where we think most of the transmission actually comes from because they’re so tiny. You just can't see them.

Frederica Freyberg:

This is a bad year for ticks?

Susan Paskewitz:

This year has been a bad year for ticks. I predicted it would be a good year in the sense there wouldn’t be many because of the drought last year. But we sample roughly eight to ten different locations throughout Wisconsin and across all those locations we are getting two to anywhere as high as seven times more nymphal ticks than we saw last year or back through around 2006.

Frederica Freyberg:

So let’s be careful out there. Professor Susan Paskewitz, thanks very much.

Susan Paskewitz:

Thank you.

Frederica Freyberg:

You can visit Professor Paskewitz's the lab online and find out more on the Lone Star tick. Her Russell Lab link can be found on our website at wpt.org/hereandnow.