For Paul, it started with a fishing trip. For Lenny, it was an addict whose knuckles were covered in sores. Dawn found pimples clustered around her swimming goggles. Kendra noticed ingrown hairs. Patricia was attacked by sand flies on a Gulf Coast beach. Sometimes the sickness starts as blisters, or lesions, or itching, or simply a terrible fog settling over the mind, over the world.

For me, Morgellons disease started as a novelty: people said they had a strange ailment, and no one — or hardly anyone — believed them. But there were a lot of them, reportedly 12,000, and their…