Even before he was released from the hospital to begin a long rehabilitation, he vowed he would once again be hiking on the rustic trails above his home.

Today Mr. Tull, 63, drives his own car, sometimes takes over the controls of a private plane, and goes on an annual trout-fishing trip to Colorado with friends. But he has not been able to hike that trail.

“That is one of the things I miss most,” Mr. Tull, now retired and receiving a disability pension, said in a telephone interview from his home. “Every single hour of every single day, the plague affects our lives, but about the only time I really get angry these days is when, because of my physical condition, there is something I want to do but can’t.”

He has appeared in several television documentaries, speaking to medical researchers around the world and dealing with a posse of journalists as his very private ordeal has been played out in public.

“Basically Lucinda and I surrendered our privacy to the press and the people who make documentaries,” Mr. Tull said. “But you know what? That didn’t bother us a bit. Lucinda had been an actress and I had been a trial lawyer. We were used to it.”

Ms. Marker, who has started to write about their ordeal, says that after 10 years she is coming to terms with it emotionally and psychologically. Yet many aspects of their case still puzzle medical experts.

In particular, no one knows why she was so easily cured while he nearly died.

Bubonic plague is transmitted by fleas that feed off pack rats, ground squirrels and prairie dogs in the mountains of New Mexico and several other states. According to the Centers for Disease Control and Prevention, the disease probably came to the United States around 1900, in Asian rats that escaped from ships in the port of San Francisco.