Understanding the Causes of Lyme Disease

The Environmental Protection Agency is backing one of the nation's top Lyme disease researchers in an effort to better understand how illness survives in the environment, and how to cut down on infections in humans.

With more than 20,000 cases diagnosed every year (including one this summer in the author) Lyme disease is the most common disease passed from animals to humans. It is caused by a bacteria that lives primarily in the blood of white-footed mice and certain other woodland mammals, like chipmunks. It is passed to ticks in their early life stages, and then can be passed on to humans as those blood-sucking arachnids seek out bigger hosts for blood meals.

Lyme, if caught early, causes no serious or long-lasting symptoms. A flu-like illness and a bulls-eye rash are the most common early symptoms. Untreated, it can lead to debilitating problems like arthritic joint pain, neurological damage and heart problems.

The EPA has awarded a $750,000 grant to the Cary Institute of Ecosystem Studies in Millbrook, N.Y., so Ecologist Rick Ostfeld can continue ground-breaking research into the ecological conditions that lead to disease outbreaks.

Lyme disease is one of the classic examples of an epidemic made by environmental change: As forests and fields are carved up into subdivisions, the habitat that makes the disease spread increases. The mice and deer that carry the ticks are more numerous, as is the Lyme-causing bacteria in the mice blood, as are the people in the suburban homes where the disease is endemic. Ostfeld has conducted fascinating research showing that the loss of biodiversity in these small forest patches leads to increased incidence of disease because the tick hosts available are dominated by mice and other mammals that carry the Lyme bacteria, whereas there is a "dilution effect" in larger, healthier environments with a more diverse assemblage of wildlife.

COMMENTS ()