SCP-189: Hair-Imitating Parasite

SCP-189: Hair-Imitating Parasite SCP-189 was discovered because a man was petting his dog and her fur started moving. By then, researchers believe more than eighty percent of her hair follicles had been taken over by worms. They'd replaced so much of her coat that he could run his hand through it without knowing what he was touching. The dog was Kara, a three-year-old golden retriever. Her owner had taken her along on a six-month biodiversity survey in a remote rainforest. She probably picked up the infestation there, although nobody established exactly when it happened. They'd already returned to the United States before he noticed anything wrong. He brought in a parasitologist, and the two tried to publish a paper about this new organism. That was how the Foundation found out. It took them into custody, seized their research and eventually recruited both of them. The parasitologist ended up leading the research into SCP-189, including investigating its native populations to see whether they could be contained or wiped out. The worms can infest any mammal. Usually, an egg sac comes into contact with the skin, catches hold with microscopic hooks and stays there. Oil on the skin makes the eggs hatch, and the larvae burrow into nearby hair follicles. A larva spends two or three days feeding from the tiny blood vessels at the base of a follicle. Once it's mature, it cuts the original hair away from the root and wraps around the structures that would normally grow the next one. It starts eating the shed cells that would have become that hair. Then it grows a tail out through the skin. That tail uses pigment and keratin from the cells the worm has eaten, and it usually has the same thickness as the hair it replaced. You need a microscope to reliably tell the difference. Some worms give themselves away by coiling or lashing around when they're touched, but plenty don't. Why some move that way and others don't is still unexplained. https://scp-wiki.wikidot.com/scp-189 Adapted from “SCP-189” by “Leicontis,” SCP Wiki. This adaptation is released under CC BY-SA 3.0. Each worm has both male and female reproductive organs in the part sitting inside the follicle. It produces sacs of one to three fertilized eggs and works them into its growing tail. The eggs are usually mature by the time that section is about a millimeter above the skin. The sacs move out onto the tail's surface, where they can catch on another patch of skin and pull loose. That might be a new animal or another part of the one already carrying them. So once an infestation starts, it has a way to keep spreading without the host ever going back to wherever it picked up the first eggs. You can cut the exposed worms as easily as ordinary hair. You can pull them out, too. But a cut section can grow a new head if it attaches to a suitable host. Giving the animal a haircut could leave you dealing with pieces that are still capable of becoming more worms. Adults only last one to six hours without a host. The eggs are another problem. They can survive for years after the adult dies, with the exact maximum redacted. Finding dead worms doesn't mean everything they were carrying has died with them. If the host dies first, the adults keep feeding and grow into its tissues. Decomposition eventually produces toxins that kill the worms, but the file separately warns that eggs on dead specimens can still cause an infestation. The Foundation keeps its samples in cryogenic storage and burns the surplus. Infected test subjects go into sealed rooms with airlocks and chemical showers. Staff wear protective suits, and even bodies have to be sealed and decontaminated before they're taken out to be incinerated. There's an anti-parasitic treatment called 189-A. Infected staff receive it, and the same agent is used to clean contaminated facilities. The treatment instructions are in another document, so we don't get the details here. Who gets that treatment depends on where they fall in the Foundation's system. Infected staff are quarantined and treated. Infected D-class personnel and non-SCP animals at a Foundation facility are killed and burned. Outside the Foundation, infected humans are treated and given amnestics, while the animals are euthanized and incinerated. The checks also extend to anyone who had close contact with an infected person or animal, or entered their home or vehicle. With eggs that can transfer through contact and remain alive after the worms die, the problem doesn't end with the person standing in front of the researchers. SCP-189 is classified Safe, but there have still been outbreaks involving people and animals in different parts of the world. The numbers are redacted, and the outbreak locations aren't named. What happened to Kara shows how easily it can go unnoticed: most of her follicles were already occupied before her owner saw her fur move. Until that moment, it just looked like his dog.