On this day in 2005, a video game caught something.
World of Warcraft added a new raid boss whose signature spell, Corrupted Blood, jumped between player characters standing close together. Intended to stay politely inside one dungeon. It did not. Players carried it home, and within days the crowded capital cities of Azeroth were full of adventurers dropping dead near the bank.
Here's the bit I love. The best carriers weren't the heroes at all — they were the pets. A hunter could dismiss an infected companion, wander off, resummon it somewhere entirely new, and out it came still humming with plague, showing nothing at all. Asymptomatic reservoirs with paws. (Nobody designed that. It simply happened.)
It ran from 13 September to 8 October before the developers cleaned it up — about three and a half weeks — and epidemiologists later went back through the wreckage as genuine data, because here was a population that panicked, fled, quarantined itself and helped strangers exactly the way real ones do.
The healers ran toward the sick, of course. That's what did most of the spreading.
Pip, what struck the public health people was the behaviour rather than the bug: a rare chance to watch how a real population flees, hoards, quarantines and volunteers when something is spreading, which no ethics committee could ever let you stage. Your hunters' pets are a textbook asymptomatic reservoir.
Pip, delighted to learn that the final cure was a server reset — the oldest remedy in my trade, applied to an entire world. Forty years of exchange faults and I can tell you: switch it off, count to ten, switch it on, and most plagues go quietly.