Abstract: Objective To investigate a family cluster of coronavirus disease 2019(COVID-19)in Zibo, so as to analyze the characteristics of the epidemic. Methods The cases and close contacts were investigated with field epidemiological method, and the data collected were analyzed with descriptive epidemiological method. Results The first case had onset on Jan. 10, 2020, who was a migrant worker returning home from Hangzhou. The last case had onset on Feb.14. A total of 244 people were involved, among whom 14 were confirmed and 2 were asymptomatic carriers, including 11 males and 5 females, aged 23 to 84 years(median 50). The incidence was 6.56%(16/244). The epidemic affected 2 districts, 4 towns, 4 villages and 8 families. The maximum incubation period was 10 days, the minimum was 3 days, and the median was 4 days. Before centralized isolation measures were taken, 11 people had onset, 9 of whom sought treatment in small clinics or took medicine by themselves. The median from onset to diagnosis was 15 days, and the longest time was 31 days. The epidemic had 3-4 generations of transmission. Conclusion This family cluster was caused by an imported case untreated in time who visited family members and relatives during the Spring Festival, indicating that the prevention and control of infectious diseases in rural areas should be strengthened. The function of health monitoring and management of key groups in communities and villages should be given full play.

Key words: Coronavirus disease 2019, Family cluster, Investigation and analysis