Alana’s throat tightens. “There’s no doubt it’s the pneumonic plague?”

“None. The pathologist studied my sputum under the microscope. She’s certain it is Yersinia.”

“From which patient?” Nico asks.

“Sonia Poletti.”

“Not the construction worker?” Alana presses.

“I never came across her. But I was Sonia’s physician in the pronto soccorso—the emergency room.” Claudio’s voice cracks. “I also worked with her for the past seven years. Every week, a new photo of her bambina. Florianna. She loved that little girl so. The father wasn’t involved. Only Sonia.”

“The poor kid,” Alana says, though at the moment she’s thinking more about the child’s risk of acquiring the plague than about her future life as an orphan. “Claudio, were you masked when you attended Sonia?”

“Of course. We were aware of the risk the moment she came in to emergency. I was as protected then as you are now.”

“Then how . . .”

Claudio’s cheeks color. “The day before she came in as a patient . . . we finished our shifts at the same time. We left together. She coughed, maybe twice. She told me she was coming down with a chest cold. It was late. I was tired. It never even occurred to me . . .”

Nico pats his shoulder. “How could you know?”

“When did you feel your first symptom?” Alana asks.

“This morning. I woke up in a sweat,” Claudio says. “As soon the cough came . . . I realized.”

“So less than forty-eight hours from when you walked out with Sonia?” Alana asks, troubled by the numbers.

“More like thirty-six. It was an evening shift.”

“Did you not take antibiotics yesterday?” Nico asks. “I thought they started everyone who was in contact with Sonia.”

“You know how sensitive I am to antibiotics, Nico. Multiple allergies. Besides, I took full precautions yesterday in the emergency. I never thought I would be at risk.”

“Idiota,” Nico mutters, his sympathy gone. “You know better!”

“I’m taking them now. Besides, if this plague was going to kill me, it already would have.” But Claudio’s worried eyes belie his casual tone.

“What about your family?” Alana asks.

“I am divorced. No children. It’s just me and the plague now.” Claudio forces a laugh. “Frankly, it’s no worse company than the ex-wife.”

Someone steps into the room. It takes Alana a moment to recognize Byron Menke behind his hood and mask. “Dr. Oliva, Dr. Vaughn, can I have a word in private?”

Nico doesn’t budge. “We can speak here. Claudio is a colleague.”

“I realize.” Byron nods to Claudio and then turns to Nico. “But this concerns only the task force members.”

“Speak to Alana. I will catch up later. I am staying here with this fool.”

Alana follows Byron out of the ER. They slip off their gear inside the decontamination zone. As they wash their hands for a third time, Alana asks, “Have you ever seen an outbreak of the plague comparable to this one?”

“Bigger,” Byron says. “In Madagascar, three years ago. There were ten times as many patients—”