Analysis on the infection source of the first local cluster epidemic caused by the VOC/Gamma variant of SARS-CoV-2 in China.
10.3760/cma.j.cn112150-20220802-00772
- VernacularTitle:中国首起由SARS-CoV-2 VOC/Gamma引起的本土聚集性疫情溯源调查分析
- Author:
Yang YU
1
;
Ji Yu ZHANG
2
;
Hai MA
3
;
Yang HAN
2
;
Li Xiao CHENG
2
;
Xue Ying TIAN
2
;
Ju Long WU
2
;
Yan LI
2
;
Yu Wei ZHANG
2
;
De Ying CHEN
1
;
Ji Zhao LI
1
;
Jin Bo ZHANG
1
;
Ze Xin TAO
2
;
Zeng Qiang KOU
2
;
Aiqiang XU
4
,
5
Author Information
1. Weihai Center for Disease Control and Prevention, Weihai 264200, China.
2. Shandong Center for Disease Control and Prevention, Jinan 250014, China.
3. Rongcheng Center for Disease Control and Prevention, Rongcheng 264300, China.
4. Academy of Preventive Medicine, Shandong University
5. Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan 250014, China.
- Publication Type:Journal Article
- MeSH:
Humans;
SARS-CoV-2;
COVID-19;
Epidemics;
China/epidemiology*
- From:
Chinese Journal of Preventive Medicine
2022;56(12):1789-1794
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To investigate a SARS-CoV-2 epidemic reported in Rongcheng City, Weihai, Shandong Province. Methods: The SARS-CoV-2 nucleic acid positive patients and their close contacts were investigated, and the whole genome sequencing and genetic evolution analysis of 9 variant viruses were carried out. An infection source investigation and analysis were carried out from two sources of home and abroad, and three aspects of human, material and environment. Results: A total of 15 asymptomatic infections were reported in this epidemic, including 13 cases as employees of workshop of aquatic products processing company, with an infection rate of 21.67% (13/60). Two cases were infected people's neighbors in the same village (conjugal relation). The first six positive persons were processing workers engaged in the first process of removing squid viscera in the workshop of the company. The nucleic acid Ct value of the first time were concentrated between 15 and 29, suggesting that the virus load was high, which was suspected to be caused by one-time homologous exposure. The whole genome sequence of 9 SARS-CoV-2 strains was highly homologous, belonging to VOC/Gamma (Lineage P.1.15). No highly homologous sequences were found from previous native and imported cases in China. It was highly homologous with the six virus sequences sampled from May 5 to 26, 2021 uploaded by Chile. The infection source investigation showed that the company had used the squid raw materials captured in the ocean near Chile and Argentina from May to June 2021 over the last 14 days. Many samples of raw materials, products and their outer packages in the inventory were tested positive for nucleic acid. Conclusion: This epidemic is the first local epidemic caused by the VOC/Gamma of SARS-CoV-2 in China. It is speculated that the VOC/Gamma, which was prevalent in South America from May to June 2021, could be imported into China through frozen squid.
