Lyme Disease: Treat Mice to Treat Ourselves?

Paul G. Auwaerter, MD


January 17, 2017

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Hello. This is Paul Auwaerter, speaking for Medscape Infectious Diseases. Today's blog will be a bit of a departure from the usual clinical issue or report, and instead will focus on a public health problem.

With new gene editing technology, such as CRISPR, there are now thoughts among a number of scientists that one might genetically engineer certain vectors. For example, with gene editing, mosquitoes might no longer effectively transmit malaria, dengue, Zika virus, or any number of pathogens that currently cause grave problems to human populations.

The article that I wanted to discuss today is not in a journal, but a New Yorker magazine article written by Michael Specter, who has written a number of scientifically oriented articles for the lay audience, including this one about Lyme disease.[1] This article focuses on whether gene editing technologies might be used to tackle the problem of Lyme disease.

Lyme disease is a vector-borne illness transmitted by ticks. Ticks effectively transmit Borrelia burgdorferi mainly by feeding on small mammals, such as deer mice, which are chronically infected with the Lyme disease bacterium.

Specter focuses on a young biologic engineer by the name of Kevin Esvelt, who has the idea of using genes to produce significant immunity to B burgdorferi (Lyme disease), splicing them into mice, and breeding that population so that it is effectively immune to Lyme disease. Then these mice could be released to breed with native mice and therefore eventually render the entire rodent population free of this. Ticks will feed on mice that no longer have Lyme disease, so they will no longer effectively transmit it to humans. It certainly has biological plausibility.

The article focuses on some of the questions that I am sure many of us might have when dealing with this kind of experiment of nature. I took three key points from the article as a clinician, thinking about how we tackle a human disease, perhaps outside of humans.

First, is altering nature a problem? Many people feel that existing practices or natural selection are the best methods, but is it really best to completely cull deer or eradicate ticks by using pesticides or some kind of mass administration of antibiotics? None of these sound as effective as an elegantly engineered approach in which mice have a couple of genes that only seem to target Lyme disease, and we effectively render them neutralized.

The second issue is that for this experiment to succeed, the proposal is to release these mice on an island in a controlled experiment on Martha's Vineyard or Nantucket, where Lyme disease is endemic and a major problem. The article emphasizes Esvelt's technique and insistence on complete and total transparency, with research not being part of a corporate enterprise that can present concerns about profit motives, and proceeding only if island residents were to agree with the experiment.

The third issue is whether Lyme disease has caused enough fear that such an experiment would be worthwhile to carry out. Of course, there are always downsides. People have pointed out that these gene editing technologies could weaponize creatures—mosquitoes, mice, and others—and that this could produce far graver circumstances. Certainly, I think this deserves some consideration.

Why are we at this point where people are looking at dealing with vectors or reservoirs of Lyme disease, when we have had an effective Lyme disease vaccine in the past that is no longer marketed?[2] That is a very different story. It points to some of the potent issues that surround Lyme disease with respect to political arguments and dealing with unknowns, as well as what we think we know about the disease.

We need to figure out how to effectively help decrease what seems to be an increase in these infections, not only in the islands off New England but also elsewhere in the country—infections that are capable of causing ill health that can persist in some people.


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