The night after my father's funeral home viewing, I got dizzy, started throwing up, curled up in the fetal position, my hands cramped closed and my legs locked up. I had tunnel vision and asked my wife to call an ambulance. Spent the night and morning in the hospital getting fluids and couldn't attend my own father's burial. At the church service, they had to get a different priest, because the main priest got violently ill. At the church, my brother-in law keeled over. His wife (my sister) keeled over at the cemetery. Several of my relatives left the funeral home the night before and got violently ill back home in Wisconsin. Another of my sisters keeled over after the burial. One of my cousins was a tough guy from the Navy. He didn't go to the Dr. for 3 days after the funeral. He went into renal failure and lost his kidney function. Had to get a transplant from his sister.
The culprit? Norovirus. Everyone crying, hugging, kissing, shaking hands spread it around. 8-9 of us needed hospitalization. Crap like that spreads fast. So, I have a pretty good first-hand experience with how fast poop can hit the fan.
My in-laws were on a cruise from Washington to Alaska back in the 90's. 1/3 of the entire ship got norovirus. She knew someone at the cruise line that later told here they had to gut the ship of all carpet, curtains, bedding, etc... after that cruise. It was down for months.