SEIR Transmission dynamics model of 2019 nCoV coronavirus with considering the weak infectious ability and changes in latency duration

Pengpeng Shi; Shengli Cao; Peihua Feng

Considering that the Chinese Spring Festival began on January 23 and the Chinese government initiated effective prevention, control and quarantine measures for the whole people, it can be considered that there are few new imported cases in all provinces, and the impact of migrant population flow can be basically ignored. Therefore, the premise of carrying out dynamic model research on infectious disease transmission is sufficient. The model in this paper is based on the classical SEIR model. The classic SEIR model divides the population into S (Susceptible), I (Infected), E (Exposed), and R (Recovered). In this model, it is also assumed that all individuals in the population are at risk of infection. Antibodies will be produced when the infected individual recovers, so the recovered population R will not be infected again. In addition, quarantine measures to prevent and treat infectious diseases are also taken into account in the model. The population components in the model also includes Sq (isolated susceptible), isolation exposed Eq (isolated exposed) and Iq (isolated infected). In view of the fact that isolated infected individuals will be immediately sent to designated hospitals for quarantine and treatment, this part of the population will be converted to hospitalized H in this model. Therefore, the original populations S, I, and E respectively refer to susceptible, infected, and exposed individuals who have missed quarantine measures. The isolated susceptible person is reconverted to the susceptible person after isolation. Both the infected and the exposed have the ability to infect the susceptible, turning them into the exposed. The transformation relationship among different groups of people is shown in Fig. 1. Figure1 . Modified SEIR propagation dynamics model It is assumed that the quarantine ratio is q, the probability of transmission is  , and the contact rate is c.