Review
Frequently, news of epidemic and disease arrives in the form of terse bulletins, quarantine flags flapping from ship masts, and hordes of panicked refugees. News of Lyme disease came to me from my neighbor, Don Baur, after he'd returned from a trip to California in the summer of 1976. In the Los Angeles Times, he had found a small article about a mysterious disease in our town, Old Lyme, Connecticut. Sitting on the hot sand of Old Lyme Shores, with the cold water of Long Island Sound before us and the close-cropped lawns of the summer cottages behind us, it seemed an unlikely place for a new disease to erupt suddenly. Yet it turned out to be the perfect place.
| "A small book about a small bug in a small town." |
p>Why that should be so is the subject of Arno Karlen's Biography of a Germ. The germ in question is the corkscrew-shaped bacterium Borrelia burgdorferi, an agent of what is now called Lyme disease. Karlen's
biography traces the evolution of Lyme disease from a handful of arthritis
cases in southern Connecticut to its present status as the most commonly
reported tick-borne disease in the United States.p>Biography of a Germ is 178 pages - a small book about a small bug in a small town. The book is easy, enjoyable reading; no specialized knowledge is required to understand or appreciate the well-crafted information laid out in its pages. The bite-size chapters are not conceptually linked, lending that the reader may feel free to skip around without fear of missing earlier facts, or spoiling any climatic revelations. Karlen's musings on Latinized taxonomy, the historical eroticism of the flea, and the smallness of bacteria may be interesting chapters in their own right, but are not a necessary prelude to meeting the subject of this microbial biography.p>When the Lyme disease bacterium, B. burgdorferi, does appear, Karlen introduces it as "Bb." It is a friendly sounding moniker for a pathogen; though the author notes, "I have no particular passion for this germ . . . " Yet, Karlen gives a number of reasons for wanting to play Boswell to Borrelia.
Bb, he writes, illustrates interesting facts about germs and ecological adaptation. Bb is greatly affected by climate, flora, and human activities.
It escaped detection for decades and is now considered "new" in the sense that it has finally attracted the attention of the public and the medical profession. These are all good reasons, but they could just as easily be used to justify biographies of Hantavirus, Ehrlichia, or Pfiesteria.
| The author's inspiration: Irony. |
p>Irony is an unusual reason to write about an infectious disease. Yet Karlen acknowledges such a motivation when he notes that the rise of Bb is an example of people doing the right thing - restoring woodlands and welcoming back wildlife - only to unleash a new disease in their restored Eden.p>One unstated reason for tracing the story of this seasonal pest may be proximity: the author lives in New York, knows the Connecticut shoreline, and is inundated by local media coverage of Bb. Both New York and Connecticut rank at the top in U.S. states reporting incidences of Lyme disease; New Jersey runs a close third. New York's Westchester County is a hot zone for ticks and tick-borne infections, and area newspapers are full of springtime reminders about Lyme disease and ticks. Vaccine trials have been conducted in the tristate area, and agitated support group members wave placards and fire-off letters to newspaper editors about the dangers of Lyme disease.TABLE WIDTH=150 ALIGN="right" CELLPADDING=15 BORDER=0>
| The bacterium is impressively adaptable. |
p>Whatever the motivation, Karlen gives the reader an articulate, thoughtful tour of Bb and its world. It is a strange world in which this tiny corkscrew of a creature seems to wander haplessly among an odd assortment of hosts, including mice, deer, lizards, birds, horses, dogs, and people. That it can do so, writes Karlen, is evidence of Bb's impressive adaptability to different environments. A tiny, nearly brainless, bloodsucking tick called Ixodes scapularis aids this species hopping. Ixodes is Bb's RV: part home, part transport. The tick is a vagabond, like Bb, and hitches surreptitious rides on passing mice, birds, and pant legs.p>Once attached to a host, the tick literally digs in for a blood meal. A biochemical battle quickly ensues between the hungry tick and the reluctant host. Karlen provides vivid descriptions of the ingenious molecular attacks and counterattacks that take place on a small patch of the host's skin. The tick releases anesthetics, anti-inflammatories, and anticoagulants to keep the blood flowing. The host counters with coagulants, cytokines, and antibodies. While this silent struggle is taking place, Bb starts to activate genes and synthesize new proteins for its trip from the tick gut to the salivary glands, then into the host's skin, and, eventually, the bloodstream.p>Once inside the new host, Bb begins a game of hide-and-seek with the host's immune system; happily, it doesn't always win. Karlen notes that many people living in endemic areas have antibody evidence of prior exposure to Bb, but no memory of a tick bite and no symptoms bad enough to have warranted a visit to the doctor. Moreover, presence does not always mean disease.
| Being a parasite is as hazardous as being a host. |
p>In an insightful chapter about the relationship between Bb and the tick, the author asks an original question, "Is the tick sick?" Not all ticks carry Bb, so it is probably not a normal constituent. Some ticks carry multiple germs, including Bb, Babesia, and Ehrlichia species, as well as viruses. A single microbe like Bb may not hurt the tick, but it is hard to imagine it is happy ingesting a menagerie of germs with its blood meal. Perhaps being a parasite is as much a health hazard as being a parasitized host.p>Karlen uses the question of sick ticks as a reminder of the interconnectedness of life, especially as it relates to parasitism and infectious diseases. We enter an environment - a jungle or the backyard - not as detached observers, but as participants, shedding germs from our bodies and clothes, collecting other germs, and attracting the hungry attention of vectors mindlessly seeking to barter still more germs for a drop of blood.
| There are more tick-friendly environments. |
p>Lyme disease is often called a new disease; however, Karlen notes that it is not. What is new about it is the increased degree of interaction with the Ixodes tick. Today there are more tick-friendly environments in the United States; there are more ticks, and therefore more opportunities to pick up tick-borne infections. Bb has always been around; it just took us a while to realize it was there. Why did it take so long? Karlen summarizes the history of who knew what and when they knew it. It is an interesting tale of how a disease comes to be recognized as a disease.p>Patients looking for information about Lyme disease treatments and diagnosis will find little useful information in Biography of a Germ. The book is about the history and ecology of a now famous infectious disease. Readers interested in such subjects will find informative descriptors of the anatomy, physiology, and genetics, of this marvelous microbe, but may be disappointed by the absence of references. Otherwise, Germ is enjoyable reading and a welcome addition to the library of infectious disease literature.
