ObjectiveTo understand the seropositivity of neutralizing antibodies (NAb) and low-level NAb against SARS-CoV-2 infection in the community residents, and to explore the impact of COVID-19 vaccination and SARS-CoV-2 infection on the levels of NAb in human serum. MethodsOn the ground of surveillance cohort for acute infectious diseases in community populations in Shanghai, a proportional stratified sampling method was used to enroll the subjects at a 20% proportion for each age group (0‒14, 15‒24, 25‒59, and ≥60 years old). Blood samples collection and serum SARS-CoV-2 NAb concentration testing were conducted from March to April 2023. Low-level NAb were defined as below the 25^th percentile of NAb. ResultsA total of 2 230 participants were included, the positive rate of NAb was 97.58%, and the proportion of low-level NAb was 25.02% (558/2 230). Multivariate logistic regression analysis indicated that age, infection history and vaccination status were correlated with low-level NAb (all P<0.05). Individuals aged 60 years and above had the highest risk of low-level NAb. There was a statistically significant interaction between booster vaccination and one single infection (aOR=0.38, 95%CI: 0.19‒0.77). Compared to individuals without vaccination, among individuals infected with SARS-CoV-2 once, both primary immunization (aOR=0.23, 95%CI: 0.16‒0.35) and booster immunization (aOR=0.12, 95%CI: 0.08‒0.17) significantly reduced the risk of low-level NAb; among individuals without infections, only booster immunization (aOR=0.28, 95%CI: 0.14‒0.52) showed a negative correlation with the risk of low-level NAb. ConclusionsThe population aged 60 and above had the highest risk of low-level NAb. Regardless of infection history, a booster immunization could reduce the risk of low-level NAb. It is recommended that eligible individuals , especially the elderly, should get vaccinated in a timely manner to exert the protective role of NAb.

Objective:To understand the infection status, epidemiological characteristics and drug resistance of Diarrheagenic Escherichia coli (DEC) in Shanghai and provide evidence for the disease surveillance. Methods:The epidemiological data of diarrhea cases in Shanghai from 2016 to 2022 were collected from Shanghai Diarrhea Comprehensive Surveillance System, and stool samples were collected from the cases for DEC detection. The drug resistance data was obtained from Chinese Pathogen Identification Network. Statistical analysis was conducted by using χ2 and fisher test. Results:In 24 883 diarrhea cases detected during 2016-2022, the DEC positive rate was 9.13% (2 271/24 883), the single DEC positive rate was 8.83% (2 197/24 883) and the mixed DEC positive rate was 0.30% (74/24 883). The main type of DEC was Enterotoxigenic Escherichia coli (ETEC) [4.33% (1 077/24 883)]. The DEC positive rate was highest in people aged ≤5 years 18.48% (22/119). The annual peak of DEC positive rate was observed during July - September [5.91% (1 470/24 883)]. The DEC positive rate were 9.47% (554/5 847) and 9.02% (1 717/19 036) in urban area and in suburbs, respectively, Enteroaggregative Escherichia coli (EAEC) [3.98% (233/5 847)] and ETEC [4.56% (868/19 036)] were mainly detected. From 2016 to 2019, the DEC positive rate was 9.42% (1 821/19 330), while it was 8.10% (450/5 553) from 2020 to 2022, the main DEC types were ETEC (4.87%, 941/19 330) and EAEC (4.70%, 261/5 553). The multi-drug resistance rate was 40.21% (618/1 537). The top three antibiotics with high drug resistance rates were ampicillin [64.74% (995/1 537)], nalidixic acid [58.49% (899/1 537)] and tetracycline [45.09% (693/1 537)]. Conclusions:Compared with 2016- 2019, a decrease in DEC detection rate was observed during 2020-2022, and the main type of DEC detected shifted from ETEC to EAEC. The prevalence of multi-drug resistance was severe. Therefore, it is necessary to further strengthen the surveillance for DEC drug resistance and standardize the use of clinical antibiotics.

Objective:To analyze the growth characteristics of different genotypes of Japanese encephalitis virus (JEV) in different cell lines, and to provide scientific basis for the selection of cell lines in the study of JEV.Methods:BHK-21, Vero, C6/36, PK-15, DF-1, N2a, SH-sy5y and MDCK cell lines were selected. The proliferation ability of genotype 1 (NX1889 strain), genotype 3 (P3 strain) and genotype 5 (XZ0934 strain) JEV in these cell lines was evaluated by plaque assay and RT-qPCR.Results:Significant cytopathogenic effects (CPE) were observed in BHK-21, Vero, C6/36, DF-1, N2a and PK-15 cell lines across all three JEV genotypes. However, no significant differences in CPE characteristics were observed within the same cell line. SH-sy5y and MDCK cell lines did not show significant CPE, but virus proliferation was detected in SH-sy5y cell line, while MDCK cell line were found to be insensitive to JEV. No significant difference was observed in the proliferation curves of G1, G3 and G5 JEV in BHK-21, Vero and SH-sy5y cell lines. In C6/36 and PK-15 cell lines, the titer of G1 JEV was higher than that of G3 and G5. In DF-1 cell line, G5 demonstrated a higher titer than the other two genotypes, whereas in N2a cell line, G5 showed a lower titer than the other two.Conclusions:There are differences in the proliferation of three different genotypes of JEV in different cell lines, which can provide reference for the study of JEV in different directions.

Objective:To elucidate the etiological and epidemiological characteristics and epidemiological patterns of viral acute respiratory infections (ARI) in Shanghai during 2023, with the aim of providing robust laboratory evidence for effective prevention and control strategies against related respiratory diseases and facilitating risk assessment.Methods:Respiratory pathogens were detected in the clinical surveillance specimens submitted by sentinel hospitals through multiplex PCR, as part of the multi-pathogen surveillance of acute respiratory infections in Shanghai during 2023. The obtained detection result were statistically analyzed in conjunction with sample information.Results:The positive detection rate of viral pathogens in 2023 was 21.17% (984/4 648), with rates of 33.53% (504/1 503) observed in ILI cases and 15.62% (480/3 145) in SARI cases. Influenza A virus (FluA) was the predominant virus detected, accounting for 13.7% (637/4 648). Other viruses identified in the surveillance samples included influenza B virus (Flu B), human rhinovirus/enterovirus (HRV/HEV), respiratory syncytial virus (RSV), human metapneumovirus (HMPV), parainfluenza virus (PIV), adenovirus (ADV) and human bocavirus (HBoV). Regarding temporal distribution, HRV/HEV and RSV exhibited the highest detection rates during the second quarter at 2.27% each (28/1 236). PIV had its peak during the third quarter at a rate of 2.49% (35/1 405), and HMPV showed prevalence mainly during the third and fourth quarters, with detection rates of 2.63% (37/1 405) and 2.35% (32/1 360), respectively.Conclusions:In acute respiratory infection surveillance cases in Shanghai in 2023, Flu A emerged as the predominant respiratory pathogen. The detection rate of HMPV ranked second only to Flu A, while other respiratory viruses such as HRV/HEV, RSV, and PIV were detected during different seasons and co-circulated. The prevalence of various respiratory viruses varied among different infected populations and over times.

ObjectiveTo present the exploration and application of a prospective follow-up research method for acute infectious disease surveillance based on natural community populations， using COVID-19 infection as an example， and to provide a reference for improving the infectious disease surveillance and early warning system. MethodsA multi-stage probability proportional sampling method was employed to sample residents from all communities of 16 administrative districts in Shanghai， with households as the units. A cohort for acute infectious diseases based on natural community populations was established. The baseline survey was conducted for all cohort subjects， and COVID-19 antigen test kits were distributed. From December 21， 2022 to September 30， 2023， prospective follow-up monitoring of COVID-19 antigen and nucleic acid was carried out on the study subjects on a weekly basis. The baseline characteristics and follow-up information of the cohort subjects were described. ResultsThe cohort for acute infectious diseases included a total of 12 881 subjects， comprising 6 098 males （47.3%） and 6 783 females （52.7%）. The baseline survey revealed that 35.2% （4 540/12 881） of the subjects had a history of COVID-19 infection. During the follow-up period from December 21， 2022 to September 30， 2023， the average incidence density in the cohort was 0.61/person-year， with a higher incidence density in females （0.63/person-year） compared to males （0.59/person-year）. Individuals aged 60 and above （0.64/person-year） and those with underlying health conditions （0.67/person-year） had a higher incidence density. Healthcare workers showed a notably higher incidence density （0.84/person-year） than that in other occupational groups. As of September 30， 2023， a total of 340 subjects in the cohort experienced secondary infections， with a median interval of 170 days between the first and second infections. ConclusionThis study applies cohort study method to acute infectious disease surveillance， providing crucial data support for estimating infection rates and forecasting alerts for acute infectious diseases in the community. This method can be promoted and applied as a new approach for acute infectious disease surveillance.

Objective:To investigate the correlation between cardiac polyps and gastroesophageal flap valve (GEFV).Methods:The clinical, endoscopic and pathological data of 349 patients with cardiac polyps (the cardiac polyp group) visiting Affiliated Hospital of Yangzhou University from January 1, 2016 to December 31, 2021 were retrospectively collected, and the same number of non-cardiac polyp patients (the non-cardiac polyp group) were matched in the same period as control according to the propensity score. The clinical, endoscopic and pathological data of the two groups were compared.Results:After matching with propensity score, there were 296 patients in each group, with no significant differences in smoking, acid reflux, heartburn, Helicobacter pylori infection, bile reflux, reflux esophagitis or pancreatitis between the two groups ( P>0.05). Compared with the non-cardiac polyp group, the risk of cardiac polyps increased in GEFV Ⅱ patients ( OR=3.046, 95%CI: 2.100-4.419, P<0.001) and GEFV Ⅲ patients ( OR=4.202, 95%CI: 2.299-7.681, P<0.001). Compared with the non-cardiac polyp group, the risk of cardiac polyps increased in patients with GEFV abnormalities ( OR=2.822, 95%CI: 1.615-4.931, P<0.001). GEFV abnormalities was associated with the cardiac polyp site ( χ2=22.169, P=0.003) and was not significantly associated with cardiac polyp size, number, morphology, intestinal metaplasia of the surrounding mucosa or intraepithelial neoplasia ( P>0.05). Conclusion:The occurrence of cardiac polyps is related to GEFV, and the patients with GEFV abnormalities are more likely to develop cardiac polyps.

Objective: To retrospectively analyze the epidemic characteristics and spatial distribution of vomiting and diarrhea outbreaks in schools and kindergartens in Shanghai from 2015 to 2019, so as to provide the scientific evidence for optimizing prevention and control of vomiting and diarrhea outbreaks in schools and kindergartens. Methods: Data collection and analysis were carried out on the vomiting and diarrhea outbreaks reported to Shanghai Municipal Center for Disease Control and Prevention from 2015 to 2019. Epidemiological characteristics were analyzed and compared. The proportion and incidence of outbreaks in schools and kindergartens were calculated, and the influencing factors of outbreaks were analyzed by multivariate Logistic regression. The index of Moran s I was used for the global and local spatial auto correlation analysis. Results: Among the 344 vomiting and diarrhea outbreaks, 98.26% occurred in kindergartens, primary schools, middle schools and other educational institutions. The median number of cases per outbreak was 15. The number of suspected outbreaks and the percentage of cases involved peaked in 2015 ( 60.00% , 84.35%) and then decreased year by year to 16.00% and 38.80% in 2019. About 86.98% of the outbreaks were transmitted by human to human contact. Among the 329 outbreaks with samples collected from cases and/or environments, the main pathogen detected was norovirus ( n =280), and sapovirus was detected in outbreak for the first time in 2016. The outbreaks showed obvious seasonality, with two peaks (November, March) and one trough (July), and the majority of outbreaks occurred in primary schools (44.38%) and kindergartens (32.84%). Compared with kindergartens, the probabilities of suspected epidemic outbreaks in primary schools, combined schools, middle schools and other educational institutions were higher (adjusted OR =6.40, 9.16, 12.64 , 5.58, P <0.01). The proportion and incidence of outbreaks in educational institutions in different districts showed no high-high aggregation areas. Conclusions Primary schools and kindergartens are key places for the prevention and control of vomiting and diarrhea outbreaks. Targeted prevention and control measures should be strengthened at the beginning of each semester and before the peak of the epidemic each year. Timely reporting of symptoms, suspension of school admissions after symptoms appear and standardized disposal of vomit are effective measures to reduce interpersonal transmission and control the scale of an outbreak.

Objective To investigate the prevalence of parasitic infections in market-sold aquatic products in Shanghai Municipality, and to understand the knowledge and practice towards food-borne parasitic diseases among residents, so as to provide insights into the surveillance and control of food-borne parasitic diseases. Methods Freshwater products, seawater products and pickled products were randomly obtained from agricultural trade markets, supermarkets, retail stores and restaurants in Huangpu, Putuo, Minhang and Qingpu districts of Shanghai Municipality from 2020 to 2023. Parasite metacercariae and larvae were detected in these aquatic products using pressing method, digestion method and the dissection method, and the detection of parasitic infection was compared in different types of aquatic products. In addition, the knowledge and practice towards food-borne parasitic diseases were investigated among residents aged 10-80 years old who randomly selected from agricultural trade markets, supermarkets, community streets and other population concentration areas in these four districts by questionnaire in 2023, and the awareness of food-borne parasitic diseases knowledge and percentage of healthy behaviors formation were analyzed. Results A total of 2 109 aquatic products sampled from Huangpu, Putuo, Minhang and Qingpu districts of Shanghai Municipality from 2020 to 2023 were detected, and there were 317 products detected with parasitic infections, with an overall detection rate of 15.03%. There were 8 products detected with parasitic infections in 1 221 freshwater products, with a detection rate of 0.66%, and Clonorchis sinensis was the predominant parasite, which was detected in Pseudorasbora parva, Rhodeus amarus and Carassius auratus. There were 82 products detected with parasitic infections in 501 seawater products, with a detection rate of 16.37%, and Anisakis was the predominant parasite, which was detected in Trichiurus lepturus, Larimichthys polyactis, Pneumatophorus japonicus, Collchthys lucidus, Mugil cephalus, Larimichthys crocea, Scomberomorus niphonius, Stromateoides argenteus and Cololabis saira. There were 227 products detected with parasitic infections in 387 pickled products, with a detection rate of 58.66%, and the prevalence rates of Echinostoma metacercariae were 76.27% (225/295) in Bullacta exarata and 11.11% (2/18) in crab pastes, respectively (χ² = 159.511, P < 0.05). No Paragonimus infection was found in freshwater shrimps, crabs and pickled products, and no Diphyllobothrium latum larvae infection was detected in freshwater and seawater fish. Questionnaire surveys showed that the awareness of food-borne parasitic diseases knowledge was 79.00% (222/281), and the percentages of washing hands before and after meals, not drinking filtered water or tap water directly, not eating raw or semi-raw food, being willing to change special dietary preferences or bad living habits for health, and being willing to learn more about food-borne parasitic diseases knowledge were 99.64% (280/281), 72.24% (203/281), 56.23% (158/281), 96.80% (272/281) and 97.51% (274/281) among residents living in Huangpu, Putuo, Minhang and Qingpu districts, respectively. Conclusions There are food-borne parasite contaminations in market-sold aquatic products in Shanghai Municipality. Although residents are aware of food-borne parasitic diseases knowledge, sustainable surveillance of food-borne parasitic diseases and improved health education are required to minimize the risk of human parasitic infections.

Objective Summarizes the current research status of defensive medicine in China and provides references for future research.Methods The search period spans from the inception of the database to March 2024.CNKI,Wan-fang Data,Web of Science,PubMed databases were queried,followed by literature screening based on predeter-mined inclusion and exclusion criteria.The current landscape of defensive medicine research in China was synthe-sized and categorized based on fundamental research characteristics,measurement methodologies,influencing fac-tors,and other relevant aspects.Results A total of 24 Chinese literature sources and 4 foreign literature sources were incorporated,indicating a prevalent occurrence of defensive medicine in China.Measurement tools for defen-sive medicine exhibit variability across different studies.Key influencing factors encompass doctor's demographic vari-ables such as gender,age,and professional status,institutional factors like legal frameworks and medical in-surance,and sociol-cultural factors such as doctor-patient relationships and adverse public perceptions.Conclusion Defensive medicine is relatively widespread and influenced by various factors in China.It's urgent to explore the for-mation mechanism of defensive medicine from multiple perspectives and provide evidence for passive defen-sive medicine governance.

Objective Summarizes the current research status of defensive medicine in China and provides references for future research.Methods The search period spans from the inception of the database to March 2024.CNKI,Wan-fang Data,Web of Science,PubMed databases were queried,followed by literature screening based on predeter-mined inclusion and exclusion criteria.The current landscape of defensive medicine research in China was synthe-sized and categorized based on fundamental research characteristics,measurement methodologies,influencing fac-tors,and other relevant aspects.Results A total of 24 Chinese literature sources and 4 foreign literature sources were incorporated,indicating a prevalent occurrence of defensive medicine in China.Measurement tools for defen-sive medicine exhibit variability across different studies.Key influencing factors encompass doctor's demographic vari-ables such as gender,age,and professional status,institutional factors like legal frameworks and medical in-surance,and sociol-cultural factors such as doctor-patient relationships and adverse public perceptions.Conclusion Defensive medicine is relatively widespread and influenced by various factors in China.It's urgent to explore the for-mation mechanism of defensive medicine from multiple perspectives and provide evidence for passive defen-sive medicine governance.