Mar 31, 2025

Machtinger harnesses the power of collaboration to solve complex problems

Erika Machtinger is a veterinary entomologist whose work impacts wildlife, agriculture, industry, and public health across the U.S. Her efforts hinge upon the unique, interdisciplinary ecosystem of researchers and resources at Penn State.

In 2019, pest control product manufacturer Thermacell was experiencing serious trouble with one of its consumer products, the Tick Control Tube. Quality-control testing revealed that it performed in a wildly inconsistent manner. Sometimes, the tubes did exactly what they were designed for – killing ticks that carry Lyme and other diseases. In other cases, they failed completely.

Unable to explain these conflicting trial results, Thermacell was ready to discontinue the product altogether – a painful decision considering the time, effort and money spent on its development. Then the company decided to reach out to Erika Machtinger, associate professor of entomology at Penn State.

Machtinger, a self-described “horse girl from coastal Maine who fell in love with the weird things bugs do,” is a veterinary entomologist—one of just two dozen or so she estimates are working in academia across the U.S. She also leads the nation’s first and only vector-borne disease extension team, which is charged with educating the public about pest-related disease transmission.

Intrigued by the challenge brought by Thermacell, Machtinger and her lab got to work evaluating their Tick Control Tubes, which are essentially cylinders filled with a soft material, like cotton, that has been treated with the pesticide permethrin.

“I always wondered why there were such different trial results,” Machtinger explained. “We started working with these tubes and we'd find some had absolutely no cotton taken, while some had all of it taken.”

Despite its name, the Tick Control Tube actually attracts outdoor mice, not ticks. The mice collect the pesticide-infused cotton to build nests, and while the permethrin is safe for them, it’s deadly for any ticks hitching a ride. The tube’s ease of use is key to its value. Very few other long-term products are available to consumers who want to kill ticks without having to hire pest control professionals. Moreover, other pesticides are applied broadly in the field, and thus may impact other insect species as well, including beneficial insects such as pollinators.

Though Tick Control Tubes are simple in design, their purpose is serious. Lyme disease, a tickborne illness, can cause a variety of symptoms from rashes and fevers to arthritis, chronic neurological issues, and heart damage. In 2022, more than 62,000 cases were reported to the CDC, with 90 percent coming from just 15 hot spots in the Northeast, mid-Atlantic, and upper-Midwest regions.

Machtinger noted the instructions for the tubes had been developed for what she calls the “entomological risks.” The manufacturer had focused on countering the threat of the ticks, but as it turned out, the real key to effective deployment was understanding the ecology of the mice.

“We did a little camera trap study to see if adding an odor played a role in attracting the mice. And when we were doing that, we found that's not the important part. The important part was we ran that from the summer into the fall. We noticed a lot more cotton was being used in the fall.”

Machtinger’s lab discovered that by deploying the tubes when mice were preparing to bed down for the winter, they could undermine a key refuge for overwintering ticks, leading to dramatically reduced numbers in the spring. This was the insight that changed everything. The problem had nothing to do with the product itself. It was all about using it at the right time. Machtinger and her team published their results, and Thermacell changed the wording of their directions.

“Thermacell did a 180 and said, ‘no, we need to market these. Let's keep them on.,’” Machtinger explained. “And so, we were able to keep a product on the market—one of the only ones that homeowners can use.”

A further and much larger study, funded by the Centers for Disease Control and Prevention (CDC), will commence in April 2025. It will evaluate the tubes performance across a variety of habitats and ecological types, with much more data collected for consideration.

“We’re looking at vegetation and soils, getting more information about the ecology at each one of these locations. And we're doing acoustic surveys of hawks, which prey on mice, looking at whether movement of these animals may differ based on what's in the plot. Hopefully at the end we can correlate tick densities to some of these features that we see in these plots, but also look at the overall question: did this work? Is it going to be effective to protect somebody on a particular hiking trail?”

Penn State is a national leader in this kind of ecologically complex research, which helps explain why the university is host to one of just four CDC Training and Evaluation Centers for vector-borne diseases in the nation. The scale of Penn State’s extension and research operations allows for unique confluences of resources and expertise, attracting a variety of challenging projects.

“Penn State has built a framework for research that breaks down the siloes between faculty working in different disciplines and scales, allowing our scientists to tackle questions and challenges form multiple perspectives – from the molecular mechanisms underlying host-pathogen interactions to the neurobiology driving animal behavior to the ecological factors influencing population dynamics of pathogens and their host” said Christina Grozinger, Director of the Huck Institutes of the Life Sciences and Publius Vergilius Maro Professor of Entomology. “Importantly, we aim to design our research questions and solutions in collaboration with stakeholders, so we address critical issues and provide strategies that can be immediately put into practice.”

For another recent study, this one tied to the poultry industry, Machtinger led the evaluation of an anti-parasite drug for the Food and Drug Administration. Developed by pharmaceutical giant Merck, the drug targeted two species of mites.

Both the northern fowl mite and red poultry mite can have devastating effects on the health of domestic chickens, causing anemia or even death and severely impacting the productivity of the poultry industry.

“There are cases, particularly in broiler breeder birds, where these mites overwhelm their ability to fight the parasite. They go anemic and die,” said Machtinger. “But there are sub-lethal effects too. With parasites feeding on them, the birds excessively groom. They pluck their feathers. That causes a reduction in feed conversion, and so it's wasteful for the producer where the bottom line is pretty narrow.”

In an industry where many producers oversee tens or hundreds of thousands of birds, treating each individually is impractical. But the Merck drug can be added to the animals’ drinking water supply. “The mites are super resistant to current chemicals and there are no options for organic facilities,” Machtinger noted. “So, this is a drug that veterinarians can prescribe that reduces populations to pretty much zero.”

This kind of study is possible at very few places outside of Penn State, which is home to specialized scientists like Machtinger as well as the capable staff and required level of facilities available at the University’s Poultry Research and Education Center.

“Penn State has a strength in poultry science in general, so we can work with these animals. And then this kind of culture of collaboration that we have at Penn State, right? Animal science is not siloed, and they allowed entomologists to come in and work with them and learn from them. We had wonderful staff there who were amazingly helpful, and several folks in poultry who were holding our hands through all of this. We've worked with five years with that group and developed good relationships.”

The Merck drug is in use in Europe, but the United States has stricter protocols.

“We did layers first, and then we did four of the breeder birds because we have such wonderful facilities here at Penn State. Merk said, ‘Well, this is easy. We hadn't found a place where we can do these broiler breeder studies.’ And we were able to make that happen here.”

These specialized ecosystems of expertise and resources come up a lot in Machtinger’s work at Penn State. She’s a member of the Huck Institutes’ Center for Infectious Disease Dynamics (CIDD), Ecology institute, and Center for Chemical Ecology, and she readily namechecks individual Huck scientists who have been valuable resources and collaborators: disease ecologist Kurt Vandegrift, vector biologist Jason Rasgon, acorologist Joyce Sakamoto, virologist Joyce Jose, and others.

“One great thing about Penn State is these group collaborations,” Machtinger said. “CIDD has been fantastic. I operate a little differently, I think, than a lot of the folks in CIDD. When I have a question that's more of a basic nature, they're the first ones I go to, especially if it's pathogen-based or immune-based.

“And I can just email them. There's no boundary there. I've had many, many awesome discussions, not just as a collaborator, but by asking ‘can I pick your brain about something? Can I ask you, is this something I should be thinking about?’ That’s been wonderful. The resources that are available intellectually as well as practically, on the ground…I don't know if they’re matched anywhere.”