1. Understanding the Reproduction Definition Understanding the Reproduction Definition

2. Reproduction Ratio (R 0 ). Definition It is the expected number of secondary cases produced by a primary case Ex. R 0 =4

3. Prevalence Nb of infected animals Time The pathogen is able to invade the susceptible population R 0 over 1

4. Prevalence Nb of infected animals Time The pathogen remains at the same level R 0 equal 1

5. R 0 below 1 Between-animal transmission cannot maintain a disease in a population Time Prevalence Nb of infected animals

6. . R 0 =1 Prevalence Nb of infected animals Time R 0 > 1 the pathogen is able to invade the susceptible population R 0 < 1 between-animal transmission cannot maintain a disease in a population Reproduction Ratio (R 0 ). Effect