Chapter 1: the nature of plagues: peter turner world war i i veteran attended a convention for the. American legions, and stayed at the bellevue-stratford hotel: two days later he fell sick and died from pneumonia, along with 33 other veterans. If ro, is greater than 1, it will lead to an ever expanding spread of the disease. But eventually the fuel" will run out, so the parasites wait for new people, or will lead to a persistent low level of disease. Because the number of susceptible individuals i large enough for the chain of transmission to be unbroken. Ro is greater than 1: type i i, peaks of infections are discontinuous, but a regular pattern of occurrence of cases. Temporary absences of diseases occur, ro is less than 1. Population of 10000 100000: type i i i, smaller communities, less than 10,000. Increased number of cases is irregular intervals, and longer periods of no disease.