What would you interpret?

Would you make the same mistake?

Around 5 days ago, I got an email reply from a friend for a game night.

"i have succumbed to the bug that was circulating around the office"

With my first glance, I assumed this person was talking about a bug, a programming bug. I assumed this person could not join the game night since he needed to fix the bug. So, I replied something. It turned out... this person was talking about Influenza :p