Directly-transmitted pathogens require a minimum population size of potential hosts. What happens if the host population is too small? What evolutionary changes in a pathogen might increase its ability to survive in a smaller population? For example, measles requires a host population about 500,000 humans, while diphtheria can remain endemic with only 50,000 humans. Develop some hypotheses for why diphtheria can survive with only one tenth the hosts measles requires - focus on how the two diseases might differ from each other in transmission rate, virulence, latency to infection, and mutation rate.
Use the equation for directly transmitted microparasites in the answer please