INTEGBI 114 Lecture Notes - Lecture 5: Compartmental Models In Epidemiology
Document Summary
Lecture #5: susceptible and infected individuals (si) model, changes over time of susceptible and infected individuals. Interested in counting how many and then predict what happens to the disease over time: mass action density dependent transmission, very simple model of si individuals leads to everyone becoming affected. Example of measuring beta b: at time 1, in a group of 100, we see 2 diseased and 98 healthy individuals, at time 2, we see 5 diseases and 95 healthy individuals. Once we know beta we can predict the course of the epidemic. This will happen if bst > y or bst/y >1 or st>y/b: corollary: for disease to increase st has to be above a threshold (y/b) Example: recovery rate of y = 0,1, average duration of infection = 10 days, b = 0. 001, threshold number of susceptible = 100. The si model with recovery: equilibrium prevalence, disease is endemic, at equilibrium, not all population is diseases.
