SEIQRS Epidemic Model and its State Estimation using Positive Observer

In this paper, the SEIQRS model, which includes exposed patients and quarantined in the SIR model and takes into account the possibility of reinfection is introduced. First, the SEIQRS of early stages of infection is formulated as a positive linear system. Next, necessary and sufficient conditions for a positive observer to exist in order to estimate the number of infected patients is given. Finally, a numerical example which gives the estimated results of infected people is shown.