Q. Lyme disease was first reported in the United States in 1977 in the town of Old Lyme, Connecticut. How far have we come?

A. We still have many unanswered questions, but there has been tremendous progress. We now know the cause of the disease, a bacterium called Borrelia burgdorferi, and its multi-system manifestations. We know many of the biologic tricks the organism uses to evade the human immune response and we know its genetic makeup, as it has been fully sequenced. We know that while most Borrelia are easily eradicated with a standard course of antibiotics, some persist despite treatment. We briefly had a vaccine on the market, which is no longer available, but a new vaccine is now in clinical trials. Despite advances in some areas, there remain serious problems, most prominently that the epidemic of Lyme disease continues to expand both geographically and in the number of new cases—an estimated 400,000 in the United States each year.

Q. What are the symptoms of chronic Lyme disease and how is it diagnosed? What percentage of Lyme sufferers go on to have chronic problems?

A. Most patients do well if the infection is recognized and treated early. In about 10 to 20 percent of cases, patients develop a more severe disease whose symptoms can include debilitating pain, fatigue, headaches, mental fog causing difficulty with memory or finding words, irritability and sleep disorders. Unfortunately, because our blood tests are antibody-based and can remain positive for years even when infection is no longer present, it is hard to determine whether a patient’s recurrent symptoms are due to persistent infection, a new infection or a post-infectious disorder.

Q. Why does post-treatment Lyme disease affect some people and not others?

A. This is an important question for which we have only preliminary answers. Infection by a more invasive strain of the Borrelia microbe, rather than one that only causes skin manifestations, increases the risk of more severe disease. Certain genetic markers increase the risk of chronic Lyme arthritis. Patients with a history of multiple physical illnesses and other life stressors may have less resilience to infection. And because the tick may transmit other microbes, some patients may have two or more infections.

Q. What are the current treatments for persistent Lyme disease?

A. There are multiple approaches to the treatment of lingering symptoms, but there haven’t been any new, large clinical trials in the U.S. on chronic Lyme-related symptoms in over 10 years. Studies in Europe of early Lyme disease indicate that some of these patients improve without further treatment over the course of one year after initial antibiotic therapy. Patients with chronic symptoms need a personalized approach based on the cause of their symptoms.

Q. Is there hope of finding a cure?

A. Absolutely. With precision medicine approaches, biomarkers are now emerging that appear able to predict who might respond to standard antibiotic therapy and those who might not. This provides an opening for testing new treatment approaches for the latter group, leading to improved long-term outcome.