“What? Who’s on first?” yelled Wally. For the record, most people refer to the acronym for the World Health Organization as W-H-O, but Wally had always pronounced it as if it rhymed with coo.

“From where specifically are these reports?”

“Tangier,” Wally said. The jocularity dropped from his tone. “And a few from Rota.”

I sat down, hard, on a tree root, recognizing the first city as one of the northernmost port cities in Africa and the second city as the site of a large American military base in southern Spain. A few meters away, Beau was hopping on one foot in a figure-eight pattern; Rorie had stretched out on a root, holding her phone above her face. They both appeared to be occupied, so I returned my attention to Wally.

“What are they saying?”

“The initial reports were of undiagnosed pneumonias, possibly an unusual viral illness, as the lung consolidations did not respond to multiple antibiotics. Fever, and, in some people, pulmonary hemorrhage. Possibly some seizure-like activity. Apparently the postmortems were strange; this wasn’t on Pro-EID, but I’m hearing in one case the lungs were nearly liquefied.”

“Okay, but—”

“There’s a wrinkle, though.”

“Yeah?”

“The first death reported by Tangier officials was a doctor. A young man. He was traveling to Morocco from his village.”

“Why is that wrinkly?”

Wally cleared his throat. “The doctor was from Chad,” he said.

I didn’t say anything. Very few people know of my history in Africa, but Wally is one of them. I’d only been boarded in internal medicine when I lived there; it wasn’t until after I’d left that I’d added a fellowship in infectious disease. My husband, Daniel, had been a surgeon, and together the two of us constituted the majority of the available physicians in the remote region where we lived.

“Kira?” Wally said. “Whatever they found on Patient Zero’s autopsy was concerning enough for rumors to begin circulating online, which is how Pro-EID Com picked it up.” He hesitated before adding in a quieter tone, “There haven’t been any direct reports to us.”

I considered this. A viral illness causing bleeding into the lungs in a young man with a presumably healthy immune system . . . Wally waited me out, no doubt anticipating the track my mind would take.

It didn’t take long to summon a specific and unsettling fear. Both Wally and I had granted a lot of thought to a particular specter from the past, a killer so contagious and so brutal its worldwide death toll may have eclipsed even that of the plague.

“Nineteen eighteen,” I said slowly. “Another Spanish flu?”

“I’m not thinking influenza specifically,” said Wally. “But the world’s overdue for something catastrophic.”

I acknowledged this in silence.