Dr. Wainwright looked confused until he realized Jack was kidding. Dr. Wainwright tittered. “Right you are,” he said.

“I’ve come about your patient Donald Nodelman,” Jack said, getting right to the point. “We have a presumptive diagnosis of plague.”

Dr. Wainwright’s mouth dropped open. “That’s impossible,” he said when he’d recovered enough to speak.

Jack shrugged. “I guess it’s not,” he said. “Fluorescein antibody for plague is quite reliable. Of course, we haven’t yet grown it out.”

“My goodness,” Dr. Wainwright managed. He rubbed a nervous palm across his face. “What a shock.”

“It is surprising,” Jack agreed. “Especially since the patient had been in the hospital for five days before his symptoms started.”

“I’ve never heard of nosocomial plague,” Dr. Wainwright said.

“Nor have I,” Jack said. “But it was pneumonic plague, not bubonic, and as you know the incubation period is shorter for pneumonic, probably only two to three days.”

“I still can’t believe it,” Dr. Wainwright said. “Plague never entered my thoughts.”

“Anybody else sick with similar symptoms?” Jack asked.

“Not that I know of,” Dr. Wainwright said, “but you can rest assured that we will find out immediately.”

“I’m curious about this man’s lifestyle,” Jack said. “His wife denied any recent travel or visitors from areas endemic to plague. She also doubted he’d come in contact with wild animals. Is that your understanding as well?”

“The patient worked in the garment district,” Dr. Wainwright said. “He did bookkeeping. He never traveled. He wasn’t a hunter. I’d been seeing him frequently over the last month, trying to get his diabetes under control.”

“Where was he in the hospital?” Jack asked.

“On the medical ward on the seventh floor,” Dr. Wainwright said. “Room seven-oh-seven. I remember the number specifically.”

“Single room?” Jack asked.

“All our rooms are singles,” Dr. Wainwright said.

“That’s a help,” Jack said. “Can I see the room?”

“Of course,” Dr. Wainwright said. “But I think I should call Dr. Mary Zimmerman, who’s our infection-control officer. She’s got to know about this immediately.”

“By all means,” Jack said. “Meanwhile, would you mind if I went up to the seventh floor and looked around?”

“Please,” Dr. Wainwright said as he gestured toward the door. “I’ll call Dr. Zimmerman and we’ll meet you up there.” He reached for the phone.

Jack retraced his route back to the main hospital building. He took the elevator to the seventh floor, which he found was divided by the elevator lobby into two wings. The north wing housed internal medicine while the south wing was reserved for OB-GYN. Jack pushed through the doors that led into the internal-medicine division.

As soon as the swinging door closed behind Jack, he knew that word of the contagion had arrived. A nervous bustle was apparent, and all the personnel were wearing newly distributed masks. Obviously Wainwright had wasted no time.

No one paid Jack any attention as he wandered down to room 707. Pausing at the door, Jack watched as two masked orderlies wheeled out a masked and confused patient clutching her belongings who was apparently being transferred. As soon as they were gone, Jack walked in.

Seven-oh-seven was a nondescript hospital room of modern design; the interior of the old hospital had been renovated in the not-too-distant past. The metal furniture was typical hospital issue and included a bed, a bureau, a vinyl-covered chair, a night table, and a variable-height bed table. A TV hung from an arm attached to the ceiling.

The air-conditioning apparatus was beneath the window. Jack went over to it, lifted the top, and looked inside. A hot-water and a chill-water pipe poked up through the concrete floor and entered a thermostated fan unit that recirculated room air. Jack detected no holes large enough for any type of rodent much less a rat.

Stepping into the bathroom, Jack glanced around at the sink, toilet, and shower. The room was newly tiled. There was an air return in the ceiling. Bending down, he opened the cabinet below the sink; again there were no holes.

Hearing voices in the other room, Jack stepped back through the door. It was Dr. Wainwright clutching a mask to his face. He was accompanied by two women and a man, all of whom were wearing masks. The women were attired in the long, white professorial coats Jack associated with medical-school professors.

After handing Jack a mask, Dr. Wainwright made the introductions. The taller woman was Dr. Mary Zimmerman, the hospital’s infection-control officer and head of the like-named committee. Jack sensed she was a serious woman who felt defensive under the circumstances. As she was introduced, she informed him that she was a board-certified internist with subspecialty training in infectious disease.

Not knowing how to respond to this revelation, Jack complimented her.

“I did not have an opportunity to examine Mr. Nodelman,” she added.

“I’m certain you would have made the diagnosis instantly had you done so,” Jack said, consciously trying to keep sarcasm out of his voice.

“No doubt,” she said.

The second woman was Kathy McBane, and Jack was happy to turn his attention to her, especially since Ms. McBane had a warmer demeanor than her committee chairwoman. He learned she was an RN supervisor and a member of the Infection Control Committee. It was usual for such a committee to have representatives from most if not all the hospital departments.

The man was George Eversharp. He was dressed in a heavy cotton twill blue uniform. As Jack suspected, he was the supervisor of the department of engineering and was also a member of the Infection Control Committee.

“We certainly are indebted to Dr. Stapleton for his rapid diagnosis,” Dr. Wainwright said, trying to lighten the atmosphere.

“Just a lucky guess,” Jack said.

“We’ve already begun to react,” Dr. Zimmerman said in a deadpan voice. “I’ve ordered a list to be drawn up of possible contacts to start chemoprophylaxis.”

“I think that is wise,” Jack said.

“And as we speak, the clinical computer is searching our current patient database for symptom complexes suggestive of plague,” she continued.

“Commendable,” Jack said.

“Meanwhile we have to discover the origin of the current case,” she said.

“You and I are thinking along the same lines,” Jack said.

“I’d advise you to wear your mask,” she added.

“Okay,” Jack said agreeably. He held it up to his face.

Dr. Zimmerman turned to Mr. Eversharp. “Please continue with what you were saying about the air flow.”

Jack listened as the engineer explained that the ventilation system in the hospital was designed so that there was a flow from the hall into each room and then its bathroom. The air was then filtered. He also explained that there were a few rooms where the air flow could be reversed for patients with compromised immune systems.

“Is this one of those rooms?” Dr. Zimmerman asked.

“It is not,” Mr. Eversharp said.

“So there is no freak way plague bacteria could have gotten into the ventilation system and infected just this room?” Dr. Zimmerman asked…

“No,” Mr. Eversharp said. “The air induction in the hall goes into all these rooms equally.”

“And the chances of bacteria floating out of this room into the hall would be low,” Dr. Zimmerman said.

“Impossible,” Mr. Eversharp said. “The only way it could leave would be on some sort of vector.”

“Excuse me,” a voice called. Everyone turned to see a nurse standing in the doorway. She, too, had a mask pressed against her face. “Mr. Kelley would like you all to come to the nurses’ station.”

Dutifully everyone started from the room. As Kathy McBane stepped in front of him, Jack got her attention. “Who’s Mr. Kelley?” he asked.