Parasitology is a medical thriller series by Mira Grant, (aka Seanan McGuire).
It is 2027. The hygiene hypothesis — the idea that we have scrubbed our environment so much that we can't handle incursions by germs and parasites — has found a solution. SymboGen, the mega corp, has come up with a pill that contains the egg of a genetically engineered tapeworm called the Intestinal Bodyguard which regulates the body. Diabetic? The Intestinal Bodyguard will make sure you have enough insulin to never worry. Live in a third world country with no women's rights? The Intestinal Bodyguard will emit hormonal birth control. It's healthcare made simple. One pill, every two years — never get sick, never have to remember to take meds for your issues.
The story follows Sal Mitchell, who — six years before the narrative begins — had a seizure behind the wheel of her car, resulting in a car accident that left her gravely injured and in a coma from which no one expected her to wake. As her family discussed whether to unplug her life support, Sal awoke. The family was thrilled to have Sal back. SymboGen was delighted to take the credit and foot the bills for Sal's rehabilitative therapy (so they could study her). Sal, for her part, wasn't sure how to feel about any of this, as she couldn't even remember how to speak.
Things take a sharp turn into the weird and terrifying as people begin coming down with a strange sickness. Most people call it sleeping sickness — but it looks frighteningly similar to becoming a zombie.
Sal and her boyfriend Nathan begin to wonder what's going on, and whether SymboGen has been entirely honest about their product.
The series consists of Parasite, Symbiont, and Chimera.
This series contains examples of the following tropes:
- Action Survivor: Both Sal and Nathan.
- Affably Evil: Dr. Banks.
- Air-Vent Passageway: Sal tries escaping a mall this way in Symbiont, only to find Ronnie waiting for her at the end; once he saw that she'd entered the vent, he was able to casually stroll over to the exit grating while she slowly crawled her way through the duct.
- All There in the Manual: There's an in-character Twitter account for SymboGen.
- And Then John Was a Zombie: The end of the first book reveals Sal's parasitic implant is in her brain, meaning she's just like Adam and Tansy — a sentient tapeworm inhabiting a human body.
- Ax-Crazy: Tansy.
- Bio Punk
- Big Bad Friend: Sherman, one of the SymboGen scientists who is friendly with Sal and who gets taken away after Chave's Intestinal Bodyguard takes over, turns out to have been in on the scheme the whole time, and another one of Shanti's experiments who betrayed her.
- Calling the Old Man Out: It takes a long grounding period and a very ill-advised ruse by her father to elicit more information out of her, but Sal eventually gathers the courage to tell her parents off and make them revoke their custodianship of her.
- Corrupt Corporate Executive: Banks.
- Dark Action Girl: Disconcertingly combined with Genki Girl in the person of Tansy.
- Death of a Child: One of the first sleepwalking victims that Sal encounters is a little girl.
- Driven to Suicide: Richard Jablonsky, one of the co-founders of SymboGen is revealed to have killed himself when he realized how bad things were getting, and couldn't convince Banks to listen.
- Dysfunctional Family: Played with. Sal after the accident has an entirely different personality than Sally before the accident. Pre-accident Sally was a bit of a hellion and contrary for the sake of being contrary. Sal is compassionate and empathetic, willing to talk to her family. Her family is torn between missing the old Sally and appreciating the new Sal — to a point.
- Her parents' reaction to Sal going off the grid for a day is explained in-universe, but also called out as being completely out of order.
- Evil-Detecting Dog: Animals such as dogs and cats can tell when a person's Intestinal Bodyguard is taking over, due to the sudden change in hormones. However, they react normally to those who have already been taken over, such as Tansy and Sal.
- FaceHeel Turn: Sherman is revealed to be one of Dr. Cale's sentient tapeworms who defected to Banks's side.
- Faking the Dead: Dr. Shanti Cale dropped off the radar right around the time the Intestinal Bodyguard went public. She is also Nathan's Missing Mom.
- After Sherman is taken away by SymboGen security, Sal is told that he had been 'infected' by Chave. This later turns out to be not the case.
- For Science!: Kale's prime motivation for working for Banks.
- Foreshadowing: In his first appearance, Sherman refers to Sal's boyfriend as a 'parasite pasher', i.e. someone who kisses tapeworms. Sal later finds out she's a tapeworm.
- Hide Your Gays: Subverted. As with Grant's other works, her same sex relationships are treated as no different than heterosexual relationships. Unfortunately coupled with Bury Your Gays, played straight: of the lesbian couple in the first book, one goes sleepwalker, and the other stays by her hospital bed only to be strangled by her.
- Ironic Nursery Tune: Don't Go Out Alone, verses of which are scattered across the gaps between chapters. Technically, not a tune, but just as creepy as most instances of this trope.
- More ironically, it actually has a tune - it is uncertain which version came first, but the author did a filk about Silent Hill. Presently there don't seem to be plans to record Don't Go Out Alone (probably because then she'd have to write the whole thing).
- Literary Allusion Title: The interludes are named after books from The Bible (Genesis, Exodus, Numbers, Judges).
- LEGO Genetics: The Diphyllobothrium symbogenesis Intestinal Bodyguard parasite is made from a mishmash of human and parasite DNA. Because of the intertwining of DNA from disparate species, taking antiparasitics might have an adverse effect on their host's DNA as well. It's later revealed that SymboGen's parasite includes DNA from another source: Toxoplasma gondii, a parasite which can affect its host's behavior.
- Mad Scientist: Dr. Shanti Cale.
- Missing Mom: Nathan's mother died abruptly on him at a young age. They were very close, so he took it hard and required years of therapy. She turns out to not have died after all, having had her death faked by SymboGen so her family would remain safe in case things went wrong. Nathan takes it all in stride, having figured out who Shanti Cale was long before the events of the book, though he's not exactly happy about it.
- Morality Kitchen Sink: Sal and Nathan are the good, Symbogen the bad, as is Sherman with Shanti Cale and Sal's father somewhere in the middle.
- Not Using the "Z" Word: So far the possessed are being referred to as "sleepwalkers".
- Parasite Zombie: The sleepwalkers.
- Puppeteer Parasite: The Intestinal Bodyguards are becoming more aware and taking control of their hosts, thanks to the little extras that the people working on them threw in.
- The Reveal: Book 1 ends with Sal discovering she's one of the tapeworms.
- Shown Their Work: As if Newsflesh's Kellis-Amberlee virus wasn't convincing enough, in this series, Seanan McGuire explores yet another plausible way for a Zombie Apocalypse to come to pass. Think Toxoplasma gondii and its espoused mind-control abilities are just another horrific sci-fi fabrication? Think again.
- Spock Speak: Having to learn English all over again leaves Sal a bit overly formal in her speech patterns.
- Technically Living Zombie: The sleepwalkers.
- That Man Is Dead: Without any memories from before the accident, Sal is insistent that she be considered a separate person from her former self, which is why she doesn't go by Sally anymore.
- Tomato in the Mirror: Post-crash Sal turns out to be her tapeworm, who took over Sally's brain in response to her body shutting down after her car crash. She works this out after meeting Adam and Tansy, but faints from the shock and forgets until the end of the book.
- 20 Minutes into the Future: Starts in the year 2027.
- The Un-Twist: Many people called Sal being a tapeworm as soon as their abilities were revealed. In fact, Sal herself realizes it at the same time but has a mental break over it, and the rest of the book is her struggling to not remember it.
- You Shall Not Pass!: Tansy pulls this on a mob of sleepwalkers in order for Sal to get away. Nathan isn't sure if she survived or not, but Dr. Cale claims this isn't the first time it's happened.
- Zombie Apocalypse: Is headed in this direction by the end of the first book.