Expert: Walter Hintz - 1/27/2006

Question
What causes plagues to stop ? ? ?     What caused the 1918 flu plague to stop killing people ? ? ?

Answer
Hi Al
  There can be more than one reason depending upon the causative organism.  Some people have a greater susceptability to a parasite and they perish.  Those who survive build up an immunity or were already immune.  Thus the plague tapers off and ends with few cases occuring.  This is probably what happened with the flu epidemic.
The black plague was caused by a bacterium.  It was spread partially by a rodent and it was checked in part by a decrease in the rat population.  Cats are sometimes given credit from helping end the black plague.