On March 6, the Health Bureau of Huangdao District, Qingdao reported the tracing results of the epidemic situation. The details are as follows: At present, the tracing work of the epidemic has come to an end. After careful investigation and analysis of human transmission, material transmission and environment, the epidemic is a small-scale family gathering and gathering of relatives and friends caused by accidental infection. The cause of the epidemic is personnel infection caused by receivin...