In order for disease to spread there is a chain of infection that needs to occur. what is the order of the chain? a. infectious agent, reservoir, portal of exit, vector, indirect contact transmission, susceptible host b. susceptible host, age, infectious agent, portal of entry, means of transmission, vector c. infectious agent, reservoir, portal of exit, means of transmission, portal of entry, susceptible host d. age, infectious agent, portal of entry, portal of exit, vector, susceptible host

In order for the disease to spread there is the chain of infection. The answer on the situation is C.It starts with the Infectious agent such as bacteria and virus. It then would settle in a reservoir which is the habitat in where the agent will live and multiply. It can be in a human or animal. It then would leave the reservoir through a portal of exit like nose and would be transferred through means of transmission such as by coughing or sneezing and germs would be caught through the portal of entry such as nose and mouth and would settle in a susceptible host like humans.

Blood transfusions were rarely done and often fatal; they were outlawed until the nineteenth century.