Abstract
What is already known on this topic? Following 110 days of no new confirmed cases of COVID-19 in Tianjin Municipality, a case was confirmed on June 17, 2020. A total of 136 local cases had been reported previously. What is added by this report? The 137(th) case was found in a dishwasher working in the western dining room of a hotel in Tianjin. Epidemiological investigations and laboratory research indicated that this case was likely transmitted from an asymptomatic individual that had recently visited several public places in Beijing Municipality and was working as a chef in the same workplace as the patient. Sequencing and analysis found that the COVID-19 virus genome found in the 137(th) case was 100% identical to sequences from the recent outbreak in Beijing's Xinfadi Agricultural Product Wholesale Market. What are the implications for public health practice? A combination of meticulous epidemiological investigation and detailed laboratory research can promptly identify the source of COVID-19.