insects. But the stiffened filament … strange … it’s too highly developed to be a superfluous vestige.’
Aimee crossed her arms. ‘Maybe direct epidermal introduction …?’
‘Hmm, interesting … You’re thinking maybe that rigid filament is some sort of delivery mechanism — like a genetic injector? Could be used for some type of nucleic material transmission … acting like a virus? No, no, no, that’s impossible for a bacterium.’
Michael shook his head. Aimee could tell that his mouth was turned down behind his mask.
Maria clapped her gloved hands together, making a dry, muffled sound. ‘Why not? It could attach to the skin surface and simply inject its biological or genetic material into the cell. Michael, think … Remember chlamydia — it’s a bacterium but in some ways it acts more like a virus. It
She swung around in her chair, opened another case beside the desk and withdrew a couple of items. The first — a small, flat black square she stuck to her chest —
‘You, soldier girl, come here.’
Franks just looked at the CDC woman, her only movement the slow chewing of her gum. Aimee knew Casey Franks wouldn’t follow any command given to her that didn’t directly parallel the orders she had received from Alex.
‘What do you need?’ she asked the scientist.
Maria scowled at Casey and slid her eyes to Aimee. ‘A blood sample, and these suits need to remain unbroken. Come on, quickly, this is vitally important.’
Aimee could see now that the object in Maria’s hand was a lancet. ‘I’ll give you one,’ she said, ‘but give me the lancet and I’ll do it back in my cabin where I can clean up.’ She knew the lancet was sterile and sealed, but needed to ensure she had a sterile solution to slap on the skin immediately after it was pricked.
She held out her hand to Maria. Maria grabbed her wrist and, in one swift motion, pricked the skin of her forearm. A spot of blood welled up like a small polished ruby.
‘Hey!’
‘Be a big girl now, Dr Weir — you know this is important.’
Maria wiped a glass slide over the blood, then released Aimee’s hand, ignoring her intense glare. She handed the slide to Michael, who took it to the isolation cube.
Aimee grabbed a bottle of iodine from the table top and splashed some on the red dot.
Casey Franks leaned in close. ‘That’s why I gave you the gun, toots.’ She sniggered softly and went back to chewing.
Michael pushed the slide into a small chamber on the side of the cube, inserted his hands in the mounted gloves, retrieved the slide and moved it up to the small raised work surface.
Maria focused on the new medium and spoke over the top of her screen. ‘Add in a small amount of the bacterial fluid in the D-900 lateral quadrant.’
Michael did as he was told. Maria’s screen now contained gridlines cutting the sample up into defined quadrants. She touched the black square on her chest to turn it on, then began a commentary as she focused in on the sample.
‘It’s not red,’ Casey Franks said.
Maria swivelled in her chair to look patronisingly at Franks for a few seconds before turning back to her screen. ‘That’s right, dear. Blood at this magnification is more a pinkish-yellow. That’s because the red blood cells are suspended in plasma, which is about ninety per cent water. Here we are: plenty of healthy corpuscles, nice shape, though a little pale.’ Maria turned once more, this time to Aimee. ‘You need to eat more red meat, and get some rest; you’re low on iron, and oxygen as well, I’d say.’
She gave a small smile and pulled back on the magnification so the near-transparent, biconcave circular discs could be seen floating within the fluid. She moved her cursor around and navigated to the upper left quadrant of the screen where Michael had placed the bacterium.
‘Dr Weir’s Hidden Key — although I think I prefer Hades Bug as well, Hades for short. Anyway, it survives deep below ground and therefore measures its life in geological terms. After being locked beneath miles of stone, in the dark and heat, it probably finds us as alien as we find it. The only difference is, where we see it as a lethal little germ, it sees us as an accidental or opportunistic food source. No malice, no planning, it’s just doing what it has evolved to do — ingest carbon, and … oh, my God …’
It appeared as though a shadow was falling across the screen as a black stain moved across the field of small red discs. The Hades’ small filaments whipped them furiously through the serum towards the blood corpuscles, just like semen rushing to fertilise an egg. Once they made contact, they rotated until their smaller rigid spike was lined up with the red blood cell wall, then punctured it. Instantly, the blood cell’s pink turned to grey, then black, before exploding to release a stain of black fluid into the pool of blood.
Michael screwed up his brow. ‘That’s odd; I was expecting a bacterial plume to be released. It doesn’t seem to be using the blood cells for replication. It’s just destroyed them without any defined outcome.’
‘Not quite,’ said Maria. ‘Look at the Hades Bug that just ingested that cell.’ She pointed the cursor at a body of the bacteria that was vibrating inside and wrestling with itself. After another second, a small dot appeared on its side. ‘Replication bubble — it’s hiving off some of its DNA and preparing to launch a daughter cell. So this is how it multiplies, by binary fusion. It’s not acting like a virus and using the cell as some form of brood nest to create duplicates from within. It doesn’t live within the cells either; it’s way too big for that. Instead, it’s raiding the contents of the cell and sucking out what it needs to use as an energy store for its own growth. It’s using Aimee’s blood cells as a grocery store … and doing it very efficiently.’
The bacterium had finished splitting; now two dark cells existed where only a few seconds ago there had been one.
Michael was literally on the edge of his small chair. ‘No wonder it can spread so quickly through our physiology — it’s using our bodies as a highway and a food source at the same time.’
Aimee peered over Maria’s shoulder to better see the detail. ‘Move to the lower quadrant,’ she said. ‘There’s always a shepherd to guard the sheep — let’s see if we can find it.’
Casey Franks stepped up behind her. ‘What are you looking for?’ she whispered.
Aimee nodded at the screen. ‘White blood cells — our last line of defence — humans have billions of them: some coded for specific invaders — fungi, parasites; and the most powerful reserved for viruses and bacteria. What type is it, Maria — an NK or neutrophil?’
‘Looks like a lymphocyte … nice big NK …’
‘NK — Natural Killer cell,’ Aimee translated for Casey.
‘Yeah, that’s my type of cell; game on.’ Franks pushed her gun up over her shoulder so it rested against her back and leaned in to look at the screen.
The NK cell was twice the size of the red blood cells and looked slightly granular around its edges. They all watched in complete silence as the black stain raced towards it. The explosions of the tiny cell walls as it advanced made the screen look like a battlefield, with all the heavy artillery stacked in the invader’s favour. When the battle line reached the large white orb of the NK cell, everyone held their breath.
The first of the Hades Bug cells crowded up against the white blood cell. It attempted to swivel its spike around, then stiffened suddenly as though it had received an electric shock. The entire cell body shuddered, and crumpled like an aluminium can in the hand of a giant. More NK cells appeared, seeming to have been called to arms by their single advance soldier.
Aimee smiled and folded her arms. ‘Chemical warfare on a micro scale — the NK have a battery of armaments, the most potent being an ability to release specific cytotoxic granules that target invading cells. Think of it as a mother ship sending out attack drones to destroy a target.’
Aimee’s smile broadened as more and more of the dark bacteria crumpled and floated away in the yellowish medium. The NK cells crowded in, almost forming a solid wall against the black tide. More of the Hades cells crumpled and drifted away as micro-fragments.
‘Chalk that up as one for the good guys,’ Franks said. ‘Hey, you’re pretty tough on the inside, Dr Weir, as well
