Re-engineering the White Footed Mouse to Prevent Lyme Disease

While ticks have received most of the blame for Lyme disease, it’s not really their fault. The true culprit is the white footed mouse. White footed mice are the primary reservoir for the bacteria that cause Lyme disease (B. Burgdorferi). Ticks that feed on the mice become infected. Then when they latch onto their next meal, the infected ticks infect the host. If you want to get rid of Lyme disease, one idea would be to get rid of the mice. Another would be to change them.

Changing the mice is what Kevin Esvelt, the head of the “sculpting evolution” group at the Massachusetts Institute of Technology, is working on. He’s using recently developed gene-editing technology to rewrite white-footed mouse DNA to make them immune to the bacteria that causes Lyme disease. To do this, he’s vaccinating mice with a Lyme vaccine that works for dogs and mice (but not humans) and then sequencing the DNA to find the protective antibodies created by the vaccinations. He can then plant the genes that create those antibodies in white footed mouse eggs so that the mice are immune to Lyme disease at birth. Even better, they spread this immunity to infected ticks that might bite them. No more infected mice means no more infected ticks and no more infected people.

To test his solution, Esvelt and his team would breed immune mice and apply for permission to release them on an uninhabited island off the coast of Massachusetts. Esvelt estimated that it would take at least a year to see results. If the number of infected ticks plummets, the experiment is a success.

Kevin Esvelt meets with Nantucket residents. Photo by Kayana Szmczak for Stat

Since over a quarter of the residents of nearby Nantucket have been infected with Lyme disease, and since Nantucket is an island, introducing the modified white mice there could follow.  Though this possibility is probably a decade away, Esvelt and Nantucket residents have already met to discuss this possibility, as well as their mutual concerns about the larger implications of manipulating the basic elements of life. Nothing will happen without the concurrence of everyone involved. Esvelt believes that efforts like this, require transparency that science has typically lacked and he has pledged to work with scientists and people who could be impacted by his work to ensure that everyone understands and is supportive of the process and the outcomes.

Actual implementation is a long ways away. Esvelt’s timeline puts possible introduction of Lyme-immune white footed mice on Nantucket at 2023. If the project on Nantucket were a success, decades down the road, it could lead to efforts to introduce immune mice to areas where Lyme disease is most concentrated in the U.S. Research continues on how something called a “gene drive” might spread genetic immunity to larger populations of white mice.

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