OBJECTIVETo investigate the molecular subtypes of 73 strains of Yersinia enterocolitica biotype 1A isolated in Shandong province by PFGE, and thereby to analyze the relationship between PFGE typing and biological characteristics.

METHODSSeventy-three strains of Yersinia enterocolitica biotype 1A were isolated from animal feces and meat products in Gaomi city and Wulian county in Shandong province from 2008 to 2009. Motility test, serum agglutination and virulent genes detection by PCR were used to learn the biological characteristics of the isolated strains. The molecular subtypes were determined by PFGE, whose relationships with motility, serotypes and virulent genotypes were also analyzed.

RESULTSOut of the 73 strains of Yersinia enterocolitica, 5 showed medium-active motility while the other 68 showed well-active motility. The dominated serotypes were O:5(17/73) and O:8(14/73), followed by O:9(5/73) and O:7, 8(1/73), and there was no O:3 serotype found. Meanwhile, 36 strains couldn't be serotyped. All the strains were negative with the gene ail, ystA, yadA and virF, yet the positive rate of ystB gene was 72.6% (53/73). The 73 strains of Yersinia enterocolitica isolated could be subtyped into 54 PFGE patterns (K6GN11SD0001-K6GN11SD0054), most of which only had 1 or 2 isolated strains, and no pattern was dominant. The strains in the same or similar cluster were from different hosts; each serotype and toxic genotype scattered in the clustering trees, without specific correlation with PFGE subtypes. 4 out of 5 strains, which showed medium-active motility, belonged to one branch, with the similarity coefficient at 80.9% - 100.0%; while all the toxic genotype belonged to type B.

CONCLUSIONBiotype 1A Yersinia enterocolitica has many clones, whose PFGE types had relations with motility, but no relations with virulent genotype and host.

Bacterial Typing Techniques ; DNA, Bacterial ; genetics ; Electrophoresis, Gel, Pulsed-Field ; Genes, Bacterial ; Genotype ; Meat Products ; microbiology ; Yersinia enterocolitica ; classification ; genetics ; isolation & purification

This study was aimed at understanding the pollution distribution pattern of avian influenza virus in the environ-ment in poultry related places in Shandong Province,to provide a scientific basis for the prevention,control,prediction,and early warning regarding human infection with avian influenza.From 2020 to 2023,6 523 environmental samples were collected in 16 cities in Shandong Province from four types of poultry-related places.Fluorescence quantitative PCR was used for nucleic acid testing of influenza A virus.Positive samples were further identified for the H5,H7,and H9 subtypes of avian influenza virus.The epidemiological characteristics of avian influenza viruses in the poultry related environment of Shandong Province were described,and inter-rate comparisons were performed with the x2 test.During 2020-2023,6 523 environmental samples were collected,and 1 007 cases positive for avian influenza virus were detected,with a positivity rate of 15.44％.H5,H7,and H9 subtypesand mixed infections were detected.H9 was the main subtype(88.48％)in positive specimens.A significant difference in positivity rates was observed among regions(x2=431.956,P＜0.001),and the highest positivity rate was 28.93％.Significant differences in positivity rates were observed among monitoring sites(x2=304.604,P＜0.001),sample types(x2=109.678,P＜0.001),and quarters(x2=64.963,P＜0.001).The positive detection rate was highest at monitoring sites in urban and rural live poultry markets(20.12％),and the positive detection rate of samples collected by wiping meat cut-ting board surfaces was higher than that of other samples(22.56％).The peak positive detection rate occurred in spring(20.31％).Widespread contamination with avian influenza virus was observed in poultry environments in Shandong Prov-ince.The H9 subtype,the main pathogen,coexisted with H5 and H7 subtypes,thus posing a risk of human infection with avian influenza.Therefore,prevention and control of avian influenza must be strengthened in key seasons,areas,places,and links.

In the context of the global pandemic of COVID-19, the epidemic intensity, epidemic characteristics and infection risk of influenza have presented new features. COVID-19 and influenza have simultaneously emerged in many regions of the world. COVID-19 and influenza are similar in terms of transmission mode, clinical symptoms and other aspects. There are also similarities in the mechanism of influenza virus and novel coronavirus on cells. At the same time, it is feasible and significant to do a good job in the prevention and control of COVID-19 and influenza. This paper discusses the relevant strategies and measures for the joint prevention and control of influenza and novel coronavirus from the aspects of influenza vaccination to prevent co-infection, simultaneous vaccination of influenza vaccine and novel coronavirus vaccine, etc., and puts forward corresponding thoughts and suggestions, in order to provide scientific support for the formulation of strategies on seasonal influenza vaccine and novel coronavirus vaccination.
Humans ; Influenza Vaccines ; Influenza, Human/epidemiology* ; COVID-19 Vaccines ; COVID-19/prevention & control* ; Seasons ; Vaccination ; SARS-CoV-2

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.
Humans ; SARS-CoV-2 ; COVID-19 ; Epidemics ; China/epidemiology*

Objective: To analyze the epidemiological characteristics, etiology and hemagglutinin (HA) gene characteristics of prevalent strains in Shandong Province from 2021 to 2022. Methods: The sentinel surveillance data of influenza-like illness (ILI) were collected in Shandong Province from 2021 to 2022. ILI specimens were detected with Real-Time PCR and virus isolation to explore the distribution of influenza viruses in different months. Three virus strains of each city were selected for gene sequencing, and the HA phylogenetic analysis was carried out. Results: In the surveillance-year from 2021 to 2022, 528 263 ILI cases were totally reported in 54 sentinel hospitals for influenza surveillance in Shandong Province. ILI visiting ratio (ILI%) was 4.07%, with the largest number in 0-4 age group (45.86%). The highly frequent season for ILI was in winter and spring, with a peak in the 52nd week, 2021 (6.62%). Totally, nucleic acid was detected in 26 754 specimens, with a positive rate of 27.10%, all of which were type B Victoria influenza. The positive rate reached a peak in the 49th week, 2021 (63.78%). A total of 295 outbreaks of ILI had been reported, in which 269 were positive for influenza virus. Most of outbreaks occurred in the primary school, with a peak in December. Gene evolution analysis showed that the HA gene in Shandong possessed high homology, 98.6% to 99.5%, with the recommended vaccine strains in 2020-2023, which was divided into two branches, V1A.3a.1 and V1A.3a.2. Conclusion: In the surveillance-year of 2021-2022, influenza is prevalent in December in Shandong Province, with a single circulating strain type. The positive rate of influenza virus and outbreak are higher than those in the previous surveillance-year. The circulating strain possesses high HA gene homology with those of the WHO vaccine recommended strains. However, the overall immune barrier of influenza virus is weak.
Humans ; Influenza, Human/prevention & control* ; Phylogeny ; Influenza Vaccines ; Orthomyxoviridae ; Seasons ; China/epidemiology* ; Virus Diseases