Phages are viruses that kill bacteria and are used to treat bacterial infections. We review the biology of phage, discuss models of phage, then formulate new stochastic models with the goal of studying the impact of variability on phage therapy. Two new stochastic models are derived based on an underlying ordinary differential equation model. A continuous-time Markov chain model and a stochastic differential equation model account for variability due to adsorption, reproduction and release of phage particles. A branching process approximation yields an estimate for the probability of phage extinction. Numerical examples highlight the importance of variability in modeling phage.
- Branching process
- Lytic cycle
- Stochastic differential equation