We had nailed it. Meanwhile, the surgeon had started Mr. Ervin on a week-long course of antibiotics. His temperature returned to normal. But there's an epilogue to Mr. Ervin's story. The month after we diagnosed his condition, researchers at Ball State University in Muncie, Indiana, published a study showing a high rate of ehrlichiosis among lone star ticks in southern Indiana.
Some researchers believe the incidence is on the rise because of changes in the region's ecology.
Oak and hickory forests are growing back, and that may be boosting the number of deer, the tick's major host. According to the Ball State study, my hometown, Jasper, Indiana, is the apparent epicenter of this infestation. With skills honed over 300 million years of evolution, the tick is a formidable foe. In the warm seasons it lies waiting for a meal of fresh blood. Then it inserts its hypostome, a swordlike probe with row upon row of microscopic teeth, and begins to suck.