Today, there are 20 new locally confirmed cases in Liaoning, including 1 in Shenyang and 19 in Huludao, and the genetic sequencing comparison of the Chinese Center for Disease Control and Prevention shows that the first case of infection in Huludao City, Liaoning Province, is highly homologous to the early cases of the epidemic in Suifenhe City, Mudanjiang. The outbreak may be triggered by the importation of returnees from other places, through activities such as living in the same village or visiting relatives during holidays.