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Understanding Lyme Disease and Where It's Found


Peter L. Salgo, MD: Hello, and thank you for joining us today on this Contagion® Peer Exchange® panel discussion focusing on Lyme disease. With the recent explosion of growth in the tick population, states and providers that have not seen cases of Lyme disease in the past, are now being confronted with the illness. Moreover, the fact that some individuals experience lingering symptoms, beyond their initial course of antibiotics, has sparked international debate among experts and advocates alike over why this is occurring, and what should be done to help these patients. Today, we have brought together a panel of experts on both sides of the debate, to better understand their perspectives, and to shed light on the impact the controversy is having on patients and on the medical community.

I am Dr. Peter Salgo, and I’m a professor of medicine and anesthesiology at Columbia University College of Physicians and Surgeons, and I’m the associate director of Surgical Intensive Care at New York-Presbyterian Hospital. Participating today on our distinguished panel are Dr. Samuel Shor, president of the International Lyme and Associated Diseases Society, and associate clinical professor at George Washington University Health Care Sciences in Reston, Virginia; Dr. Leonard Sigal, past professor and chief of the Division of Rheumatology at Robert Wood Johnson UMDNJ Medical School, and founder of Gateway Immunoscience in Stockbridge, Massachusetts; and Patricia Smith, president of the national nonprofit Lyme Disease Association, which raises money for research, education, prevention, and patient support. Patricia is also a member of Columbia University’s Lyme and Tick-Borne Diseases Research Center Advisory Committee. She’s a member of the Congressionally Directed Medical Research Programmatic Panel on Tick-Borne Diseases.

Welcome to all of you joining us here today. Why don’t we get some of the basics established right off the bat? Simple question: What’s Lyme disease?

Samuel Shor, MD, FACP: Lyme disease is the most common vector-borne or tick-borne illness in the United States and in Europe that is caused by a spiral or spirochetal organism by the name of Borrelia burgdorferi senso lato complex. That being said, most of us in the field agree with the acute phases of Lyme disease, where it can present with an acute, viral-like illness. What is more contentious is the concept of chronic Lyme disease, which we’ll get into.

Peter L. Salgo, MD: We’re certainly going to get into that, but just for the sake of establishing some definitions—this is a tick-borne disease. It’s a spirochetal disease; it causes illness, and it causes a lot of symptoms. We’ll explore them as we go along. That being said, where is Lyme disease found?

Patricia V. Smith: Well, the current studies seem to indicate that Lyme disease is found in almost 50% of continental United States counties at this point in time, and that’s an increase of 45% since 1998. A lot of the concentration is in the Northeast and the upper Midwest. However, Lyme disease is found in 43 states, but part of the problem of that whole situation of looking for the ticks is that not enough money is being offered to states to do surveillance to find out, “Where are these ticks?” So, we really don’t know the full extent of the disease.

Peter L. Salgo, MD: Just to nail this down, because I’m not sure we did really nail it—these spirochetes are transmitted to humans by tick bites, at least for the most part. It’s also worth noting that in the early days when Lyme disease was first being described, it was found in Old Lyme, Connecticut, which is in the Northeast region of the United States. And early on, everyone thought, “Oh, it’s a Northeast United States problem.” You’re telling me it’s bigger than that?

Patricia V. Smith: That’s correct. Not only is it bigger than that in the United States, but it is also now found in about 80 countries worldwide.

Peter L. Salgo, MD: Is it endemic in these 80 countries, or did this spread from 1 spot? It didn’t all start in Lyme, Connecticut, did it?

Robert C. Bransfield, MD, DLFAPA: There’s debate. On one hand, it seems like we’re more aware of it, and now that we’re more aware of it, we identify it. In years past, it was called many other things; it was called different things in Europe 100 years ago. So, the name has changed, and the name keeps changing. There was an initial 1970s definition based on a description of juvenile arthritis cases. But then, as time has gone on, there has been an expansion of the definition—although there’s debate about how to define it (whether or not to define it in a narrow way or a broader way).

Samuel Shor, MD, FACP: The other point I wanted to make is that there is precedent: a 5000-year-old mummy, Otzi, in Italy in the Alps, was found with evidence of knee arthritis and genetic evidence of Borrelia.

Peter L. Salgo, MD: As I remember, this was described initially in Lyme disease as mistaken cases diagnosed as rheumatoid.

Leonard Sigal, MD: Juvenile rheumatoid. It became obvious that the epidemiology, the placement of the cases, made no sense for juvenile rheumatoid arthritis, because that does not cluster geographically. Allen Steere, Stephen Malawista, and the team at Yale began to understand this better, and then, ultimately, the organism was found on Long Island and in Connecticut. The point to make, though, is that we’re talking about the spread of Lyme disease. The first erythema migrans case described in the United States, published by Dr. Rudolph Scrimenti, was from Wisconsin.

Robert C. Bransfield, MD, DLFAPA: So, it’s been there a while. The thing is, that as more and more wilderness gets developed and there are fewer and fewer predators to take down the deer, you see more and more Lyme disease. We’re going into endemic areas in order to basically pick up Lyme disease, because that’s where people want to live.

Peter L. Salgo, MD: We didn’t really point this out, but the lifecycle of these ticks involves deer, and where deer are endemic and ticks are endemic—that’s part of the problem.

Samuel Shor, MD, FACP: It’s important to recognize that deer really are important for 2 reasons. One is that they’re transport; they jump on the deer. The ticks jump on the deer, and it takes them from point A to point B. It also provides proximity, so that the ticks can mate. That’s the importance of deer ticks. One piece that many people don’t realize is that small mammals—white fruited mouse, etc.—are really the culture medium on which the tick feeds, which then get the Borrelia and co-infections and can transmit it to another host, such as a human.

Leonard Sigal, MD: Because the mouse is carrying the organism, and they’re usually asymptomatic.

Peter L. Salgo, MD: We’ve now heard about mice, other mammals, and deer. So, let me see if I can lay this out. There are small field animals—mice, voles—and they’ve got the ticks, and they pass these ticks to the deer…

Samuel Shor, MD, FACP: No, no.

Leonard Sigal, MD: No, no, no.

Samuel Shor, MD, FACP: The tick bites. Either the larva or the nymph bites—it could be an adult, but usually it’s the younger forms—a small mammal that is then infected with Borrelia and often with co-infections. It then has the ability to transmit to another host which, unfortunately, if humans are the next host, they will potentially get transmitted the infection.

Peter L. Salgo, MD: It can go from the small mammals, to people, or from deer to people?

Samuel Shor, MD, FACP: The deer, again, is for transport and proximity; that’s really it.

Peter L. Salgo, MD: That’s it?

Leonard Sigal, MD: It also provides a blood meal to the female to make eggs.

Peter L. Salgo, MD: But there’s a whole cycle involved with larger mammals and smaller mammals?

Leonard Sigal, MD: Yes, it’s about a 2-year cycle.

Robert C. Bransfield, MD, DLFAPA: And maybe less. Foxes are more significant, because more mammals are out of control. Going historically, it goes back millions of years with Borrelia. Fossilized amber in the Dominican Republic had Borrelia. Borrelia has been around much longer than people. It has great adaptive capability, it’s been on this planet longer than we’ve been here, and it may still be here long after we’re gone.
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