MIT scientists are genetically engineering white-footed mice to combat the spread of Lyme Disease

Credit: Courtesy of Heidi Goethert

To Fight Lyme Disease, MIT Researchers Look To White-Footed Mice

August 15, 2017

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On the Island of Nantucket, people walk their dogs and runners weave their way down the trail of Ram Pasture. It’s a popular spot — and it’s easy to see why. Hundreds of acres of untouched conservation land surround the trails. It’s a peaceful setting where deer are often spotted in the early hours, grazing. It’s also lush territory for ticks.

If you're in an area like this you want to stay on the beaten path to stay away from the tall grass,” said Roberto Santamaria, Director of Health for the Nantucket Health Department. “We had rain last night. It's perfect tick-questing season.”

Forty percent of Nantucket’s 10,000 year-round residents have either had Lyme disease or are currently afflicted.

It's become part of their daily life here. Every time you go out, you go to a pasture, you go do a hike, you go to the beaches and to the dunes, even, you want to go home and do a tick check," Santamaria said. “Tick checks are pretty arduous and they take a while, and even then, you don't even catch all ticks.”

The problem isn’t unique to Nantucket and Martha’s Vineyard. According to a 2016 study from the Centers For Disease Control, the number of reported cases of Lyme disease in the United States has tripled since 1998. The Northern part of the U.S. has seen a significant spike, thanks in part to the white-footed mouse. Scientists aren’t sure why, but these Northeast natives are more susceptible to contracting Lyme disease than any other animal. They are also abundant.

Every time you go out to a pasture, go do a hike, you go to the beaches — to the dunes, even — you want to go home and do a tick check.

Roberto Santamaria, Director of Health, Nantucket Health Department

MIT scientist Kevin Esvelt says the solution is to genetically engineer these mice so that they are immune to the bacteria that causes Lyme disease, borrelia burgdorferi.

“So our idea is, well, how about we take mice that are naturally immune, identify the DNA in their genomes that makes them immune, and then take the best such elements and put them all into one engineered strain of mice,” Esvelt said.

Esvelt and his team would do this using gene editing technology. Then, those mice would mate with the native mice, so their offspring would also be immune to the bacteria that causes Lyme disease.  

The challenge is all of the mice or nearly all the mice need to be resistant and in order to get those protective genes into the entire mouse population,” said Esvelt. “That means we have to release a lot of mice.”

One hundred thousand mice on each island, to be exact.

Unsurprisingly, some Nantucket residents have questions about releasing 100,000 genetically engineered mice onto the island. Town selectman Jason Bridges’ initial reaction was one of disbelief.

It sounded like a bad sci-fi movie and people kind of laughed. But the more presentations that we have in front of the Board of Selectmen, articles in the newspaper, people are like, oh this is a really — this is a real thing.” Bridges said. “I think everyone is getting used to the idea. But the initial visceral reaction was 'Serious? Are you serious about that?'”

The town is so serious, it has formed a steering committee to look into the idea. Danica Connors is on that committee. She’s an herbalist and says 85 percent of her clients have Lyme disease, so she’s hopeful about this project but calls herself a “healthy skeptic.”

“My question is, it's a very large leap that we're about to force. What is that going to do? Is that going to help us? Is that going to harm us?” Connors said.

Esvelt welcomes the skepticism and says even he doesn’t know the potential consequences this could have on the ecosystem and other species. That’s why he insists that the communities lead the discussion. Since he first presented the idea to the islands, Nantucket and Martha’s Vineyard have held public forums with Esvelt. On Thursday evening at 6 p.m., there will be another presentation and Q&A with Esvelt at Nantucket's Public Safety Building.

“We're going to the communities and saying 'you are in control and that's why this may not happen.' Both islands might say no, in which case this is going nowhere. That's just the way it is," he said.

...No projects on this kind of technology that could alter world population should ever be done behind closed doors.

Kevin Esvelt, MIT scientist

If Esvelt gets the green light from federal and state regulators, he and his team will test out the mice on one of Boston Harbor’s small uninhabited islands. If all goes as planned and the residents of Nantucket and Martha’s Vineyard vote in favor of the project, they could release 100,000 genetically engineered mice onto the islands as early as 2024. He says no matter what happens, it is crucial that there be transparency every step of the way.

“I’m particularly passionate about that because I view this as an opportunity to work out how we, as a society, are going to handle these technologies," Esvelt said. "And that's why I think that even research in this area should be totally done in the open. That no projects on this kind of technology that could alter a wild population should ever be done behind closed doors.”


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