When Lyme Lingers
Much recent research into Lyme only adds to its complexity. But as a public health official, Ben Beard of the CDC is also interested in progress on other fronts—for example, preventing people from getting the disease in the first place. The CDC recently contracted with Allylix, the manufacturer of a natural insecticide, nootkatone, a component of the essential oils of Alaskan yellow cedar and citrus fruits, to create a new kind of tick repellent that while toxic to ticks, is considered by the Food and Drug Administration to be a “food-grade product”—in other words, it’s thought to be safe for people, Beard says. The CDC has a licensing agreement in place and hopes to move into commercial production within five years, he says.
Also on the prevention front, public health officials hope for the return of a Lyme vaccine. In 1998, SmithKline Beecham (now GlaxoSmithKline) introduced a vaccine that was about 80% effective after three doses for at least one year. But the Advisory Committee on Immunization Practices, which advises the CDC on vaccine use, gave a tepid recommendation, suggesting use of the vaccine only in high-risk locations. Then a group of volunteers from studies of the vaccine reported arthritic symptoms. The rate of arthritis in the volunteers was the same as in the control group that didn’t get the vaccine, but sales plummeted, and the drug was withdrawn in 2002.
The CDC is currently working with Colorado State University to identify diagnostic biomarkers for Lyme—for example, a test that could detect the presence of proteins of the Lyme bacteria. But beyond these practical steps, much Lyme research will continue to focus on gaining a stronger understanding of what happens to people suffering from post-treatment Lyme-related symptoms. The CDC is funding a five-year study with New York Medical College looking at patients diagnosed with Lyme disease to find out what percentage wind up with post-Lyme disease symptoms after they finish antibiotic therapy and how those symptoms manifest themselves.
In the meantime, the ticks that transmit Lyme disease continue to spread, and the number of cases seems to be increasing. Much has been learned since the disease was first discovered almost 40 years ago, and it’s now clear what causes the infection and how to treat it effectively. However, post-Lyme disease syndromes remain problematic. As Steere puts it: “There is still much more to learn.”