Pandemic Page 40

“Of course. What do you want to know?”

“Start with her medical history. Maybe there’s something unusual in her system that wasn’t in the other victims.”

Tim called up Walker’s records, scanned through the usual list of military checkups, inoculations, physicals … then found exactly what Margaret was looking for: something unusual.

“She had lupus,” he said.

Margaret shook her head. “That can’t be it. I can’t see how an autoimmune disease would affect the crawlers. They hijack stem cells to produce copies of themselves.”

Tim looked deeper in the record. When he found the next difference, he felt his heart start to hammer.

“Jesus, Margaret … Walker underwent HAC therapy to treat the lupus.”

Margaret narrowed her eyes, not understanding. “What’s HAC therapy?”

That question surprised Tim. She hadn’t just tuned out from life, she’d tuned out from medicine altogether. She wasn’t even reading research journals.

“HAC is human artificial chromosome treatment. It’s an experimental way to treat genetic defects. The process introduces a new chromosome into stem cells. The end result is stem cells with forty-seven chromosomes instead of the normal forty-six that all cells are supposed to have. The forty-seventh chromosome probably has a myriad of immune system modulators meant to reprogram cells to stop the autoimmune effects of lupus — new transcription factors, genetic code to modify gene response, et cetera. In some cases HAC even introduces fully artificial gene sequences.”

Even as he said the words, it struck him how similar the process sounded to the Orbital’s infection strategy: targeted changes to the host’s DNA, altering the processes created by millions of years of evolution. Was humanity that far away from harnessing the very technology that threatened to wipe it out forever?

Margaret’s eyes narrowed. Her nostrils flared. Normally, she looked like she couldn’t hurt a fly, but now her expression was that of a predator.

“An artificial chromosome in stem cells,” she said. “Maybe the Orbital’s technology can’t properly integrate that forty-seventh chromosome.”

She nodded, slowly at first, then gradually faster.

“This therapy,” she said. “Where did Walker get it?”

“Let me check.” Tim read through Walker’s records. “Looks like a clinic within the Spectrum Health System in Grand Rapids, Michigan. Cutting-edge stuff, only ten people in the trial.”

Margaret thought for a moment. Her excitement seemed to grow.

“Correlation isn’t causation, but this is one h.e.l.l of a correlation,” she said. “We need to see if these new, larger crawlers colonized Walker’s brain, like the older ones colonized Petrovsky’s. Let’s find out right now.”

Tim walked to his prep tray and lifted the compact Stryker saw, preparing to cut into Walker’s skull.

PREPROGRAMMING

Perhaps a thousand modified neutrophils had reached Charlie Petrovsky’s squamous epithelium. Most of them died there, wiped out by the ever-growing apoptosis chain reaction that steadily turned Charlie into a pile of black sludge.

Some, however, held on to life, held on just long enough for a gloved hand to brush against Charlie’s skin.

When that gloved hand moved away, a dozen neutrophils moved with it.

They emitted a new chemical, an airborne signal that announced their presence to any other neutrophils that might be near. If a neutrophil detected that chemical coming from mostly one direction, it moved in that direction: flow, reach, pull … flow, reach, pull. If it detected roughly equal amounts of the chemical coming from multiple directions, it stayed where it was. This simple process created an instant implementation of quorum sensing, of individuals using a basic cue to communicate as a single individual.

The microscopic neutrophils had a relatively ma.s.sive area to cover. The equivalent, perhaps, of a dozen mice scattered onto an area the size of a dozen football fields. Much ground to cover, and yet the neutrophils had been designed for this very action.

Three were too weak to make the journey. They expired along the way, leaving nine that found each other, amorphous blobs pressing in on each other.

At the center of this s.h.i.+fting pile, three neutrophils underwent a rapid physical change. They altered their internal workings to produce a caustic chemical, a chemical specifically preprogrammed by the Orbital some five years earlier. This trio pressed themselves flat against the Tyvek material of the gloves upon which they rode. The trio started to swell, to fill with fluid, until — following those same, preprogrammed instructions — they sacrificed themselves by tearing open their own cell walls.

The caustic chemical spilled onto the Tyvek: just a microscopic drop, something not even visible to the naked eye, but enough to weaken the material, to create a tiny divot.

Another neutrophil flowed into the divot, then repeated the process, deepening the hole. Then another, and another.

The chemical burst of the last one was enough to punch all the way through.

Pressurized air flowed out, an infinitesimal, nearly immeasurable amount, sliding past the flat bodies of the seventh and eight neutrophils that climbed through the microscopic hole all the way to the glove’s inner surface. These, too, began a phase change — their bodies quickly split into dozens of tiny, self-contained particles.

Those particles flaked away, scattered like an invisible shower onto the skin of the person wearing the gloves. There the particles began to burrow.