Infectious diseases such as rubella, mumps, measles, pertussis are caused by viruses or bacteria. There is a period of incubation in the spread of these diseases. The incubation period is a period in which individuals who are attacked by viruses or bacteria began shows clinical symptoms but have not been able to transmit the disease. The spread of disease by observing the period of incubation can be represented by the susceptible exposed infected recovery (SETR) model. Immigration has an influence on the spread of disease. This is caused by immigrants who could carry the disease from their areas to other places. For this reason, the SETR model with immigration to be considered. Here we will describe the SETR model with immigration, determine an equilibrium point and state the equilibrium stability. The model is then applied to the measles disease. The SETR model with immigration can be represented as system of the first ordinary differential equations. The model has two endemic equilibrium points. It means that there is still disease at the equilibrium point. The criteria of the equilibrium points are unstable.
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