ABSTRACT
Objective@#To conduct an epidemiological investigation on a cluster of overseas imported cases of coronavirus disease 2019(COVID-19)in Qingtian County, Lishui,so as to provide reference for the prevention and control of COVID-19 imported from abroad. @*Methods@#According to the COVID-19 Prevention and Control Program (FiFth Edition) issued by National Health Commission of China,a field investigation was employed and the close contacts of the case were tracked down ;the real-time reverse transcription polymerase chain reaction (RT-PCR) assay was performed to detect the nucleic acid of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from the sputum specimens or throat swabs of cases;the epidemiological characteristics,source of infection,route of transmission and disposal of the cluster were analyzed. @*Results@#From March 1 to March 6,2020,eight confirmed cases and one asymptomatic case of COVID-19 were reported. Their median age was 33 years old. The nine cases all had no fever,no decrease in leukocyte and lymphocyte levels,and the clinical symptoms of seven cases were not obvious. The asymptomatic case had been tested negative for SARS-CoV-2 for six times,but had been weakly positive for IgM antibody and strongly positive for IgG antibody. Nine cases were all the employees of the same restaurant in Begamo,Italy. They lived in three independent villas and usually had lunch and dinner in the restaurant where they worked. Begamo had COVID-19 epidemic,but the staff of the restaurant did not take any protective measures such as wearing masks and environmental disinfection. Eight cases reported to have cold symptoms in Italy during mid February. Through a closed-loop management of“all people,all sites,all chains ”,such as treatment of current cases,screening and isolation of close contacts and health education,totally 372 close contacts were traced back,yet no fever or respiratory symptoms have been found. @*Conclusions @# It was a cluster of COVID-19 cases imported from abroad. The clinical symptoms of the cases were not obvious. Qingtian County adopted the closed-loop management in time,and effectively controlled the spread of the epidemic. No second-generation cases have been found.