Ticking off points on a map of Georgia

Researchers have mapped out the distribution of the tick Amblyomma americanum in the state of Georgia in the USA.

I am currently in Atlanta, Georgia, for this year’s ASM Microbe conference. The conference is gearing up to be a great one, but in the meantime, I’m enjoying walking around the city. It’s my first time in the state, and as I sight-see, I can’t help but recall a research paper about the state that was recently published in the journal Parasites & Vectors, Mapping the distribution of Amblyomma americanum in Georgia, USA by Bellman et al.

It takes a look at Amblyomma americanum, or the lone star tick, a questing species (meaning it runs towards hosts) which often carries pathogens harmful to humans such as tularemia, southern tick-associated rash illness (STARI), and even an alpha-gal meat allergy! And it is quite pervasive in the southeastern region of the US. Despite this, no previous studies have estimated the distribution of the species in Georgia, something which Bellman et al. sought to remedy.

Sites for sampling were chosen from state parks and wildlife management areas in order to specifically look at rural parts of the state, where people might go to hunt or hike. They ensured a wide variety of ecoregions were included in the selection, such as coastal plains, valleys, forests, and more. Then, at these sites, they measured out squares, or transects. In total, there were 750 m2 transects picked out.

The actual collection of ticks occurred in 2022 between the months of March and July. In total, the researchers found “630 ticks were collected in 198 transects at 43 locations in Georgia. Of these, 568 (90%) were either A. americanum adults or nymphs, 24 were I. scapularis adults, 30 were Dermacentor variabilis adults, and eight were Amblyomma maculatum adults.” Next, after accounting for a variety of variables in the wildlife, landscape, and climate, the authors used a logistic regression model in order to look at how environmental factors could be linked to lone star ticks’ presence, and from there to estimating the distribution of them across Georgia

So, what did Bellman et al. find?

They report that “The presence of A. americanum was associated with elevation, normalized difference vegetation index (NDVI) on January 1, isothermality, temperature seasonality, and precipitation in the wettest quarter. Vast regions of central, eastern, and southern coastal Georgia (57% of the state) were categorized as suitable habitat for the lone star tick.” So, it looks like lone star ticks could potentially be present in over half the state!

Figure 4 in Bellman et al., showing the distribution of the tick.

As you can see in two of the maps the authors put together, the lone star tick is present in much of the middle of the state, though there were populations elsewhere, such as in the north and on the southern coast. Moving forward, hopefully these maps and the data can be used for messaging and to help avoid or prepare for the ticks when entering one of their habitats.


Figure 5 from Bellman et al. showing the presence and absence of the lone star tick across Georgia.
Figure 5 from Bellman et al. showing the presence and absence of the lone star tick across Georgia.

But whether you’re in the American southeast, the northwest, or anywhere at all, watch out for ticks this summer—just before my trip, I found a tick on my Pomeranian! So stay safe!

As for me, I have to get back to enjoying the Atlanta weather and the ASM Microbe conference!

View the latest posts on the BugBitten homepage