The Atlantis Plague (The Origin Mystery, #2)(79)

David nodded. “Because the plague didn’t burn out.”

“Correct,” Janus said. “It lay dormant, in the reservoir hosts—rats in this case—waiting for the correct moment in time.”

“That matches the historical record,” David said. “The first wave of outbreak was around 535, but others followed, some even more violent. We can’t imagine the toll. The bouts of plague lasted for two hundred years. Up to half of all Europeans died. Then after about 750, the outbreaks stop until around 1257—which is the next part of Martin’s note. In 1257 another volcano erupted—again from Indonesia. These are recent discoveries, but we are pretty sure that the Samalas volcano, on Lombok Island in Indonesia, erupted with an incredible force. The impact was greater than that of the Tambora event in 1815, which caused what’s known as the Year Without a Summer. From the tree-ring samples, we see the same thing in 1257: a volcanic winter that lasted for over a year. The plague rats return and plague again returns to Europe. By this time, nearly 700 years later, the historical records are more clear. This outbreak is almost exactly like the last but it gets more press—and mention in the historical record. They call it ‘the Black Death’ in Europe. But it was the same plague—”

“Bubonic plague,” Kate said.

“Exactly,” David confirmed. “The same plague, separated by almost a millennium, returning to wreak the same havoc—”

“Stop,” Kate held up her hand. “The Black Death began in Europe around 1348—almost a hundred years after this volcano—”

“True,” David said, holding up his hands. “Look, here’s the history: in 1257 a massive volcano, strangely similar in location and effect to the one in the sixth century, caused a volcanic winter and widespread famine in Europe. I can only assume the plague returned, but there was a difference this time—some sort of immunity—”

“CCR5 Delta 32,” Kate said, lost in thought.

“What?”

“Martin mentioned it to me. It’s present in up to sixteen percent of Europeans. It’s a mutation that makes them immune to HIV, smallpox, and other viruses. Possibly the bacteria that causes plague.”

“Interesting,” David said. “One of the great mysteries of history has been the origins of the Black Death. We’re pretty sure the outbreak in the sixth century, the Plague of Justinian, moved up through Africa into the eastern Mediterranean. But the Black Death was different. Same scenario—volcano, same plague—but this time, we believe the Black Death originated in central Asia. The peace provided by the Pax Mongolica enabled the Mongol armies based in central Asia to carry the disease east along the Silk Road. During the Mongol siege of Caffa in the Crimea, the invading Mongols actually catapulted infected bodies over the city walls.”

“Seriously?” Kate asked.

“Hey, it was pretty ingenious for the times. Call it medieval biological warfare. After Caffa, the plague quickly spread across Europe. Historians have assumed that migration from Asia is the reason for the one-hundred-year time difference, but it could have been—”

“The mutation,” Kate said.

“Possibly.” David wanted to get back to what he knew, away from speculation. “In the following years, thirty to sixty percent of the entire population of Europe died from the Black Death. One third of everyone in China died. In fact, it took a hundred and fifty years for the global population to recover to the level it was before the Black Death. But I’m afraid that’s where my knowledge ends. In general, I don’t know what the chronology is leading up to. I just knew what the references were, and I knew the dates.”

“I can shed light there,” Dr. Chang said. “As Dr. Janus mentioned before, our working theory has been that the current plague is simply activating past outbreaks, trying to complete some genetic transformation that was half-finished. We’ve been trying to isolate those past outbreaks to better understand how the human genome changed.” He motioned toward David. “Mr. Vale, you had it right about the link between the plagues. A few years ago, a group of researchers discovered that the Plague of Justinian was caused by Yersinia pestis, or Y. pestis—the bacteria that causes bubonic plague. The discovery was very intriguing: the two worst pandemics in recorded history—the Plague of Justinian and the Black Death—were both instances of bubonic plague. We believe in both cases there was a genetic mutation of the Y. pestis bacteria. We’ve been using the Immari to gather evidence. They procured samples from plague victims from both outbreaks. We sequenced those genomes, as well as samples of Y. pestis, from both eras. We also have samples from the Spanish flu of 1918. We found some common genetic sequences. We think they are connected to the Atlantis Plague. Based on Dr. Grey’s notes and our discussion here, I believe our data is a key piece of the puzzle, the key to finding a cure. Unfortunately, it was lost when the plague barge went down.”

Janus sat up on the couch. “Dr. Chang, I owe you an apology.”

Chang’s face glanced over, confused.

“I never fully trusted you,” Janus said. “I was assigned to you. You went along with our research, but until now I thought that you might have been an Immari loyalist, someone working to obtain my research. I withheld much of what I learned from you.” He took out a memory stick. “But I saved it on this device. Along with the research we did together. It’s all here, and I believe it will reveal the genome changes Dr. Grey was searching for—this Delta-2—the root genetic structure of the Atlantis Plague.”