This sounds distasteful, but is worth remembering.  Believe it or not, vomit appears to be astonishingly effective at spreading viruses.  Investigators were called in when 52 people at a hotel function came down with fever, nausea, vomiting and diarrhea three days after a meal.  126 people had sat down at 6 tables and one lady got very sick.  The staff  quickly cleaned up the mess, but the damage was done.  More than 90% of people at the same table as the sick woman got sick themselves as did 70% of people at the adjacent table.  People who got sick seemed to have inhaled or swallowed the infectious agent which was Norwalk-like virus, brought in by the woman.  Just a single drop of material hitting a hard surface can produce an aerosol that can travel a long way.
