Penny: It was the worst trip.
Everyone got sick over the weekend.
Leonard: Here we go.
Sheldon: What kind of sick?
Penny: The flu, I guess.
Sheldon: I don't need you to guess. I need you to know.
Now, when did the symptoms first appear?
Penny: Maybe Friday.
Sheldon: Friday. Was that morning or afternoon?
Penny: I...I don't…
Sheldon: Think, woman, who blew their nose and when?
Leonard: Sheldon, relax.
She doesn't have any symptoms. I'm sure she's not contagious.
Sheldon: Oh, please.
If influenza was only contagious after symptoms appear, it would have died out thousand of years ago.
Somewhere between tool using and cave painting, Homo habits would here figured out how to kill the guy with the runny nose.
Leonard: Penny, you'll have to excuse Sheldon. He's a bit of a germaphobe.
Penny: It's okay. I understand.
Sheldon: Thanks for your consideration, now please leave.
Leonard: You'd better go before he starts spraying you with Iysol.