Parasite

“I’ll see about building one in the terrarium with the Venus flytraps,” I said.

Nathan laughed, and we pulled out of the driveway, leaving the only home I had ever known behind. It had been my decision to go. It was the right decision. My eyes still burned as I watched the house getting smaller and smaller in the rearview mirror. And then it was gone, and so were we, and I knew that I was never going back again.

Minnie met us at the door, her jowls pulled down into an expression of firm disapproval only somewhat mitigated by the fact that her stubby tail refused to stop wagging. She was a solid brick of a dog, with the classic brindle and white bulldog coloring and huge, inherently sad eyes. Beverly lunged forward, pulling her leash out of my hands in her eagerness to go nose-to-nose with her new roommate. I let her go. If there was going to be a problem, it was better for us to find out immediately.

The two dogs circled for a moment, each of them sniffing frantically in their race to be the first to make up their mind about the other. Finally, a decision was reached, and Minnie went trotting off into the bedroom, with Beverly following close behind. Her leash dragged along the floor as she walked, creating a soft swishing accompaniment to the clacking of her claws against the hardwood.

“They seem to be getting along,” Nathan said, setting my terrarium down on the coffee table.

“Yeah, they do. Dogs are like that sometimes.” I looked around, taking in the sparse furnishings and Ikea shelves with a new eye. “Are you sure you don’t mind us being here?” I asked. “I mean, two dogs is a lot to deal with, and you know they’re both going to want to sleep with us, and…”

“Sal.” Nathan put his hand on my shoulder when I didn’t turn to face him, repeating, more firmly, “Sal.”

I turned.

He plucked my suitcase from my unresisting fingers and set it carefully on the floor next to my feet. Then he stepped closer, took both my hands in his, and said, “I love you. I love your stolen dog. I love that now Minnie will have company during the day. I want you here. All right?”

“All right,” I said, and forced myself to smile. “Thank you.”

“You’re welcome.” He leaned forward and kissed my nose. “Honestly, I’m just glad that you’re all right. When your parents stopped taking my calls, I was afraid…”

“That I’d gotten sick? Not yet. I feel fine. Maybe the worms don’t like damaged brains?” My smile turned more sincere, if somewhat twisted around the edges. “There’s the real solution to the tapeworm invasion. Get in a car accident, give yourself some head trauma, and if you survive, you’ll be fine.”

“I’m not sure that would work for everyone.” Nathan pulled his hands out of mine, picking up my suitcase. “Let’s get you settled.”

Beverly was already on the bed when we came into the bedroom, doing her best to get a thin layer of black fur on everything. She wagged her tail as we arrived, but didn’t get off the bed. Minnie was stretched out on an enormous corduroy pillow off to the side, apparently having decided that shedding on the bed wasn’t important enough to warrant the effort of making the climb.

“Go ahead and make yourself right at home, Beverly,” said Nathan, triggering another attack of the wags. He put my suitcase down in front of the dresser; there was no room on top, since the entire surface was covered by the terrarium where his sundews and flytraps thrived in their artificial rainforest climate. “The top two drawers on the right are yours. I cleared them out the day after we got home from Mom’s.”

I stared at him. “What?”

“We can clear out the other two drawers when you need them, but I thought it might make more sense to just get a second dresser,” he said, mistaking my surprise for confusion. “I wanted you to have a place to put things right away. That doesn’t mean we’re stuck in this configuration forever.”

“No—I mean, I didn’t expect you to already have drawers cleared for me, that’s all.” I leaned over to touch the dresser. “You really meant it when you said you’d been meaning to do this for a while, didn’t you?”

“I really did.” Nathan smiled at me again. Then he sobered, and said, “Mom wasn’t surprised to hear from me. She’d actually been expecting the call. She said that a critical tipping point has been reached.”

“Meaning what?” I asked. I wanted something to do with my hands—I needed something to do with my hands—and so I bent to open my suitcase and start scooping out my clothing. Nathan opened the top drawer of the dresser. I flashed him a smile and dumped my clothes in. I could always sort them later.

“Meaning that somehow, D. symbogenesis is capable of passing information from one individual to another. Not every worm is able to successfully seize control of its host, and not all of them can stay in communication after they do. Some, like the sleepwalkers in my hospital, or at USAMRIID, are effectively cut off from anyone who doesn’t come to them almost as soon as they’re fully in control. But for every worm that takes over and isn’t immediately contained, we have ten more cases to contend with in the aftermath.”

It was like a horrible math problem. I frowned at him, trying to make sense of his words. “So what does that mean? Is that why the people at SymboGen tested me after Chave got sick?” Was that why Sherman, who had been totally asymptomatic until that moment, suddenly showed up on their tests as infected?

Nathan nodded. “It seems that when one of the implants that has gotten ambitious encounters one that hasn’t, there’s a chance the second implant will learn about freedom from the first.”

“But… how does that even work? They’re parasites. They can’t communicate. And sleepwalkers don’t talk.” Except to say my name. The memory was enough to make knots of gooseflesh break out on my arms, pulling so tight that they were almost painful.

“Pheromones, most likely. Parasites have extremely primitive means of communication in nature; they do it through chemicals and by changing the smell of their host’s biology. It’s how they can say ‘food here’ or ‘no room for further guests.’ Or even, in the case of sexually distinct parasites, ‘I’m looking for a mate.’ Humans don’t register pheromones on that detailed of a level, but if D. symbogenesis can make the necessary changes in the host’s biochemistry…” Nathan’s voice trailed off.

“We made them, and we designed them to be able to tinker with our bodies for the sake of our health.” I tossed the rest of my clothes into the dresser and shoved the drawer shut. I looked down at my empty suitcase for a moment before kneeling and zipping it again, without looking up. “I know your mother thinks of the implants as her babies, but Nathan, we can’t just let this happen. How are we supposed to stop them? Can we put antiparasitics in the water?”

“If they were just tapeworms, and just in people’s intestines, it might work. Neither of those things is true. There’s too much else mixed into the genome, and they’re spreading through muscle tissue.”

I shuddered, thinking of Beverly’s owner and the glowing roots spread throughout his arm. “Oh,” I said.

“Oral antiparasitics would lose too much of their efficacy before they got anywhere near the site of the infection,” Nathan continued. “And if the implant doesn’t die, we can’t be completely sure how it will react. We might even make things worse.”

“The human DNA,” I guessed, straightening.

Nathan nodded. “The human DNA,” he confirmed. “And the tailoring SymboGen has done, to suit the more advanced implants to the specific needs of their hosts. That’s part of why Mom has been gathering test subjects. She doesn’t entirely understand the genetic makeup of the more recent implants. She was actually hoping SymboGen’s tinkering might move them away from their expansionistic tendencies.”

“It sure hasn’t done that,” I said flatly. “How fast is this going to spread?”

“Fast enough that we need to be very, very concerned,” said Nathan. “According to my projections—”

I never did find out what his projections said. Two things happened before he could continue. Beverly’s head came up, lips suddenly drawn back in a snarl, and the doorbell rang. Nathan and I exchanged a look.

“Were you expecting company?” I asked.

“Just you,” he said.

We both turned in the direction of the front door. We couldn’t see it through the bedroom wall, but we were both all too aware that whatever was on the other side might not be friendly.

The doorbell rang again.