"At one point, the liver fluke even hijacks its ant host. It compels the ant to climb a blade of grass, lock its mandible, and wait to be eaten by a grazing cow. That's how strange nature is. And what happened here is no less strange."
As Lisa continued, she appreciated being able to talk through her theories. She took a moment to explain Henri Barnhardt's assessment of the Judas Strain, how he classified the virus into a member of the Bunyavirus family. She remembered Henri's diagram, describing a linear relationship from human to arthropod to human.
"But we were wrong," Lisa said. "The virus took a page out of the fluke's handbook. Three hosts come into play here."
"If cyanobacteria are the first hosts," Gray asked, "what's the second host in this life cycle?"
Lisa stared toward the plugged opening in the roof and kicked some of the dried bat guano. "The cyanobacteria needed a way to fly the coop. And since they were already sharing this cavern with some bats, they took advantage of those wings."
"Wait. How do you know they used the bats?"
"The Bunyavirus. It loves arthropods, which include insects and crustaceans. But strains of Bunyavirus can also be found in mice and bats."
"So you think the Judas Strain is a mutated bat virus?"
"Yes. Mutated by the cyanobacteria's neurotoxins."
"But why?"
"To drive the bats crazy, to scatter them out into the world, carrying a virus that invades the local biosphere through its bacteria. Basically turning each bat into a little biological bomb. Laying waste wherever it lands. If Susan is correct, the pool would send out these bio-bombs every three years, allowing the environment to replenish itself in between."
"But how does that serve the cyanobacteria if the disease kills birds and animals outside the cavern?"
"Ah, because it utilizes a third host, another accomplice. Arthropods. Remember, arthropods are already the preferred host for Bunyaviruses. Insects and crustaceans. They also happen to be nature's best scavengers. Cleaning up the dead. Which is what the virus compelled them to do. By first making them ravenously hungry . . ."
Lisa's words stumbled, as she remembered the cannibalism aboard the ship. She fought to stay clinical, to be understood. "After stimulating this hunger, ensuring a thorough cleanup, the virus rewired the host to return here, to this cavern, to haul their catch and bring it to the pit, to feed the bacterial pool. They had no choice. Similar to the fluke and the ant. A neurological compulsion, a migratory urge."
"Like Susan," Gray said.
Lisa grew grim at the comparison. She pictured in her head the life cycle she had just described. Triangular rather than linear: cyanobacteria, bats, and arthropods. All joined together by the Judas Strain.
"Susan is different," Lisa said. "Man was never supposed to be part of this life cycle. But being mammalian, like the bat, we're susceptible to the toxins, to the virus. So when the Khmer discovered this cavern, we inadvertently became a part of that life cycle, taking the place of the bats. Spreading via our two legs instead of wings. Sickening the population every three years, triggering epidemics of varying severity."
Gray stared toward Susan. "But what about her? Why did she survive?"
"Like I said, I don't have all the answers." She remembered her earlier discussions about Black Plague survivors, about viral code in human DNA. "Our neurological systems are a thousandfold more complex than any bat or crab. And like the cyanobacteria, humans also have a great capacity to adapt. Throw these toxins into our more advanced neurological system, and who knows what miracle might churn out?"
Lisa sighed as they reached the spit of land.
As she turned, she noted a strange sight above. Puffs of smoke streamed out of the pair of the idol's eyeholes, brightly lit by the sun's fire.
"The neutralizing powder," Gray said, spotting the same and hurrying them along. "Nasser must be finalizing the upper vault's decontamination. We have no more time."
11:39 A M
At the top of the stairs Vigor knelt beside the low stone door. Seichan held the flashlight behind him. An archway of limestone framed a slab of hewn sandstone, a mix of natural and man-made.
Above the door, set into the limestone's arched lintel, was a bronze medallion, impressed into it was a perfect crucifix. Vigor had examined it, sensing Friar Agreer's hand here.
And it was confirmed below.
Vigor ran his fingers over the stone door. The solid slab had been inscribed with writing. Not angelic. Italian. It was the last testament of Friar Agreer.
In the year of the incarnation of the Son of God 1296, I set to stone this final prayer. The curse was set upon me when I first arrived and caused me great suffering, but 1 arose like Lazarus from a deadly slumber. I do not understand what bedevilment has befallen me, but I was preserved, marked in some strange manner, feverish bright of skin. For such succor, I ministered to those few who survived the great pestilence. But now a strange compunction has come over me. The waters below already begin to boil with the fires from Hell. I know it is to my death that I am driven. With great effort I did convince and oversee the construction of this seal. And I go with only one prayer on my lips. More than my own soul's salvation, I pray this door to be forever sealed with the Lord's Cross. Let only one strong in the spirit of the Lord dare open it.
Vigor touched the carved signature at the bottom.
Friar Antonio Agreer.
Seichan spoke behind him. "So after Marco left, they exposed the friar to the disease, but rather than dying, he survived. Like the woman below."
"Maybe the other glowing pagans who offered the cure to Marco's party could tell Friar Agreer would survive. That is why they picked him. But the date, 1296. He lived here for three years. The same time span Susan described between eruptions." Vigor glanced behind him. "She was right."
Seichan waved to the door. "There's more writing under the name."
Vigor nodded. "A quote from the Bible., book of Matthew, chapter twenty-eight, concerning the resurrection of Jesus from his tomb." Vigor read the quote aloud. " 'Behold, there was a great earthquake, for an angel of the Lord descended from the sky, and came and rolled away the stone from the door, and sat on it.'"
"That's a lot of help."
It was.
Vigor stared up at the crucifix carved into a bronze medallion above the door. He said a silent prayer and made the sign of the cross.
Before he could finish, he felt the ground shake under his knees. A great crash of rock echoed behind him, sounding as if the cavern had collapsed.