On a trans-polar flight from Singapore to New York a doctor comes on the overhead speakers.

"Ladies and gentlemen, we have a passenger with a confirmed case of bacterial meningitis. Even if we land as soon as possible, the passenger will not survive. It’s very likely that some of you have been infected as well. As soon as you start feeling symptoms, we need to isolate you in the first-class cabin. Fever, rash, nausea and in the late stages, a tremor in the left hand."

Moments later, several passengers rush to the first class cabin with hand tremors. The only problem is, bacterial meningitis doesn't cause hand tremors....