Objective: To perform an epidemiological survey of the first case with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Pinghu City of Jiaxing City, Zhejiang Province on March 13, 2022, so as to provide insights into the management of coronavirus disease (COVID-19) epidemics. Methods: According to the requirements of the Protocol on Prevention and Control of COVID-19 (8th Edition), epidemiological investigations were performed among 39 cases with SARS-CoV-2 infections in Pinghu City from March 13 to 20, 2022. Cases' demographics, clinical symptoms, history of immunization and exposure were collected, and close contacts were identified. Pharyngeal swabs were sampled from infected cases for detection of SARS-CoV-2 nucleic acid and whole-genome sequencing, and the source of infection and transmission route were investigated. Results: The index case for this COVID-19 epidemic was an imported case from Shanghai Municipality, who infected 6 persons via aerosol transmission when playing in the badminton venue of Pinghu National Fitness Center on March 9; subsequently, one of these infected cases infected another 18 persons when playing in the badminton venue of Jiadian Village Resident's Fitness Center in Zhapu Township on March 12. Sixteen confirmed cases were reported, and all cases were mild; another 23 asymptomatic cases were diagnosed, with no death reported. This epidemic occurred from March 11 to 20, with 3 generations of spread and a median incubation period of 3 days. The SARS-CoV-2 infected cases had a median age of 33.5 (interquartile range, 12.0) years and included 36 cases with a history of COVID-19 vaccination. There were 16 cases with fever, cough, runny nose and sore throat, and 13 cases with imaging features of pneumonia. The effective reproductive number (Rt) of the COVID-19 epidemic was 7.73 at early stage, and was less than 1 since March 21. Whole-genome sequencing identified Omicron BA.2 variant among 33 cases, which had high homology with the index cases. Conclusion This epidemic was a cluster of COVID-19 caused by imported Omicron BA.2 variant infection from Shanghai Municipality, and the COVID-19 transmission was mainly caused by indoor aerosols.

Objective To examine the effect of ground cage use on Oncomelania hupensis spread, so as to provide insights into precision snail control. Methods Twenty ground cages that were frequently used to capture rice field eels were purchased, including 11 packaging tape-made cages, 7 plastic cages and 2 nylon rope-made cages. The eel-capturing activity was mimicked, and 20 ground cages were assigned in settings with relatively high (1.00 snail/0.1 m² and higher) and low snail densities (< 1.00 snail/0.1 m²) in Xindai Township, Pinghu City, Zhejiang Province during the period from 15 : 00 to 8 : 00 of the following day on April 13, 26 and 28. The numbers of snails carried by different types of ground cages were compared in settings with different types of snail densities using the rank-sum test. Results A total of 11 cage-times were assigned in settings with a high snail density, and a total of 77 snails were captured, with a mean number of 7 snails in each cage-time and 2.15 snails in 0.1 m² ground cage. The mean numbers of snails carried by packaging tape-made and plastic cages were 2.47 snails/0.1 m² cage and 0.37 snails/0.1 m² cage, respectively. A total of 24 cage-times were assigned in settings with a low snail density, and a total of 8 snails were captured, with a mean number of 0.33 snails in each cage-time and 0.09 snails in 0.1 m² ground cage. The mean numbers of snails carried by packaging tape-made cages were 0.12 snails/0.1 m² cage; however, no snails were carried by plastic or nylon rope-made cages. The number of snails carried by ground cages was higher in settings with a high snail density than in settings with a low snail density (Z = −4.019, P < 0.01), and the number of snails carried by packaging tape-made cages was higher in settings with a high snail density than in settings with a low snail density (Z = −4.086, P < 0.01). No significant differences were found in the numbers of snails carried by different types of ground cages. Conclusion The use of ground cage in snail habitats is a contributor to snail spread.