ObjectiveTo investigate the current awareness and optimization recommendations on pneumonia with unknown etiology (PUE) surveillance among Shanghai healthcare professionals, and to provide evidence for the improvement of the surveillance system. MethodsIn December 2024, healthcare professional participants from diverse medical and health institutions were randomly selected within each stratum using a stratified cluster sampling method in all 16 districts of Shanghai for questionnaire surveys on their knowledge and suggestions for optimization of the PUE surveillance system. Descriptive statistics analyses, multivariate logistic regressions, and content analyses were used for data analyses. ResultsA total of 385 survey subjects were involved in the study, including 119 professional staffs from disease prevention and control centers and 266 from medical institutions. Those who understood the case definition for PUE correctly accounted for 67.01% (258/385). Multivariate regression model analyses showed that female gender (aOR=2.22, 95%CI: 1.36‒3.66), professionals from disease control institutions (aOR=2.02, 95%CI: 1.12‒3.72), and those who self-assessed as being familiar with the monitoring system (aOR=2.18, 95%CI:1.23‒3.89) had better understanding of the definition. Overall, 89.61% (345/385) of the survey subjects acknowledged the necessity of the surveillance system. Small number of cases meeting the case definition (54.46%, 214/379), insufficient diagnostic awareness (39.84%, 151/379), and lack of incentives for case reporting (29.29%, 111/379) were major problems for the current surveillance system, with variations observed across different types of institutions. Suggested segments for optimizing the surveillance system included monitoring purpose, case definition, form of monitoring and reporting procedure, organization mechanism, and epidemiological investigation and response. ConclusionThe necessity of PUE surveillance is commonly recognized among healthcare workers. However, the existing system falls short in terms of mastery of case definition and overall surveillance adaptability. There is an urgent need for optimization and improvement to enhance the capacity for preventing and controlling emerging and sudden respiratory infectious diseases.

Background Diarrhea disease is a common intestinal infectious disease, and its incidence is affected by meteorological conditions. A better understanding of its epidemiological patterns and influencing factors, together with the construction of reliable prediction models, is of great significance for precise public health prevention and control. Objective To clarify the epidemic characteristics of adult diarrhea disease in Shanghai, analyze the associations of meteorological factors and a web search index with adult diarrhea disease, and develop and compare forecasting models to support precise regional prevention and control. Methods Weekly surveillance data of adult diarrhea disease cases from the Shanghai Comprehensive Surveillance Information System for Diarrhea Diseases, together with concurrent meteorological observation data and web search index (Baidu index) data from 2014 to 2019, were collected. A distributed lag non-linear model (DLNM) was adopted to analyze the associations of multiple meteorological factors and the web search index with the number of diarrhea disease cases. By integrating meteorological factors and web search index data, three types of forecasting models were developed, including autoregressive integrated moving average (ARIMA), Random Forest, and extreme gradient boosting (Xgboost), and their predictive performances were evaluated. Results Adult diarrhea disease in Shanghai exhibited seasonal variation, with an major incidence peak in summer and winter peaks in some years. The number of cases declined annually after 2015. Mean temperature was significantly associated with the risk of diarrhea disease, and both low and high temperature exposures were associated with increased risks. The highest risk was observed at 32.8°C (RR=2.04, 95%CI: 1.62, 2.55), while the strongest effect of low temperature was observed at 0.9 °C (RR=1.53, 95%CI: 1.25, 1.88). When relative humidity exceeded 69%, the risk of diarrhea disease increased with relative humidity, reaching a peak at 81% (RR=1.20, 95%CI: 1.07, 1.35). When weekly cumulative precipitation exceeded 16 mm, the risk also increased with increasing precipitation, reaching a maximum at 105 mm (RR=1.23, 95%CI: 1.07, 1.42). The web search index was positively associated with the risk of diarrhea disease. Model prediction indicated that both the Random Forest model and the Xgboost model adequately captured the overall trend in diarrhea disease cases, with R² values generally exceeding 0.7. Notably, the Xgboost model demonstrated greater accuracy in capturing peak intensities. Conclusion Meteorological factors are associated with adult diarrhea disease in Shanghai. The web search index may serve as an auxiliary indicator for diarrhea forecasting. Machine learning models, with advantages in integrating multisource data, may provide effective predictive tools for the prevention and control of diarrhea disease.

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 understand the epidemiological characteristics of diarrheagenic Escherichia ( E. ) coli infection in infectious diarrhea outpatients aged 15 years and older in Shanghai and provide evidence for the development of disease control strategies .Methods:Based on multistage systematic sampling, diarrhea surveillance was conducted in 22 sentinel hospitals in Shanghai, the information about cases' demographic, clinical, and epidemiological characteristics were collected. Stool samples were collected for the detection and typing of diarrheagenic E. coli by local centers for disease control and prevention. The positive rate of diarrheagenic E. coli in different populations and seasons from 2014 to 2021 were analyzed. Statistical analysis was conducted by using χ2 test. Results:In 15 185 diarrhea cases, 8.05% (1 222/15 185) were positive for diarrheagenic E. coli. The positive rate was higher in men (8.74%, 684/7 824) than in women (7.31%, 538/7 361). The positive rate was highest in age group 15-29 years (9.14%, 335/3 665) and the annual positive rate was highest in 2021 (10.21%, 83/813), the differences were all significant ( P<0.05). In the 1 264 strains of diarrheagenic E. coli analyzed through PCR, enterotoxingenic E. coli was the most frequently identified pathogen (50.24%, 635/1 264), followed by enteroadhesive E. coli (27.93%, 353/1 264), and enteropathogenic E. coli (21.36%, 270/1 264). The positive rate of diarrheagenic E. coli showed obvious seasonality with peak in summer (13.92%, 774/5 562) ( χ2=495.73, P<0.001). Conclusions:Diarrheagenic E. coli has become a prominent pathogen in infectious diarrhea cases in Shanghai, the disease can occur all the year round with incidence peak during summer and autumn. Predominant subtypes included enterotoxingenic E. coli, enteroadhesive E. coli and enteropathogenic E. coli. Targeted prevention and control strategies are needed for diarrheagenic E. coli-induced infectious diarrhea in different age groups, seasons and for different types of infections.

Objective:To investigate the epidemiological and pathogenic characteristics of children's infectious diarrhea in Shanghai to provide evidence for developing strategies related to the control of the disease .Methods:Diarrhea outpatients were under surveillance at the pediatric intestinal clinic at five sentinel hospitals in Shanghai, with demographic, clinical, and epidemiological information collected. Fecal specimens were collected and detected for 12 bacteria and 5 viruses by district center for disease control and prevention. Characteristics of diarrhea patients were compared and analyzed from 2016 to 2021. Multi-stage systematic sampling method was adopted. The Chi-square test was used for statistical analysis.Results:Of 2 456 infectious diarrhea patients, the positive rate was 45.11% (1 108/2 456), 16.00% (393/2 456), 20.81% (511/2 456), 8.31% (204/2 456), for all pathogens, single bacteria, single virus, and diverse infections respectively. The prevalent detected pathogens were pathogenic Escherichia coli (12.95%, 318/2 456), norovirus (10.91%, 268/2 456), rotavirus (7.49%, 184/2 456), Salmonella (5.82%, 143/2 456) and Campylobacter jejuni (4.68%, 115/2 456). The pathogen spectrum of childhood infectious diarrhea patients showed noticeable seasonal changes, with a prevalent bacterial infection in summer [peaked in June, the positive rate was 34.50% (69/200)] and a prevalent viral infection in winter [peaked in January, the positive rate was 48.10% (101/210)]. The positive rates in different age groups, populations, and seasons were statistically different ( χ2=160.53, P<0.001; χ2=14.80, P=0.003; χ2=27.21, P<0.001). During 2020-2021, the number of cases of infectious diarrhea in children (284 cases/year) dropped significantly compared with the number in 2016-2019 (472 cases/year), the pathogen spectrum changed significantly ( χ2=39.02, P=0.001), and the positive findings of bacteria ( χ2=11.73, P<0.001) and viruses ( χ2=14.22, P<0.001) decreased significantly. However, the positive rate of enteric adenovirus increased. Conclusions:The pathogen spectrum of children's infectious diarrhea patients shows noticeable seasonal changes in Shanghai. Pathogenic Escherichiacoli, norovirus, and rotavirus are the most common diarrheal pathogens. In recent years, the detection of adenovirus in children with infectious diarrhea has increased. The number of children with infectious diarrhea and the positive rate have decreased significantly during 2020-2021. Specific prevention and control measures should be taken for infectious diarrhea of different ages, pathogens, and seasons.

In order to meet the needs of prevention and control of intestinal infectious diseases， a comprehensive surveillance for diarrheal diseases has been innovated and explored in Shanghai since 2012. The surveillance has extensive distribution of sentinel hospitals， systematic sampling， multi-pathogen collection， and hospital information system （HIS） as the basis， which has achieved “One system for surveillance of multiple diseases and one sample for detection of multiple pathogens". Continual active surveillance for the whole population has been conducted， covering demography， clinical information， epidemiology， pathogen detection， and drug sensitivity test for diarrhea cases. The surveillance has obtained preliminary achievements as follows. First， diarrheal diseases and their periodic changes have been characterized， in which the most prevalent pathogen of diarrhea is determined to be norovirus in Shanghai. Second， some rare pathogens and serotypes have been identified that may provide clues to the sources of outbreaks. Third， it facilitates the information sharing between public health institutions and clinical institutions， and provides scientific evidence for clinical diagnosis and treatment. In the future， Shanghai diarrhea comprehensive surveillance will be improved for expanding range and depth of surveillance， artificial intelligence assisted diagnosis and treatment， early warning of outbreaks， prediction of epidemic trends， and application of new detection technologies.

ObjectiveTo conduct on-site epidemiological investigation， emergency response， tracing of infection source and analysis of a confirmed COVID-19 case of a foreign airline cargo service staff member in Shanghai’s international airport， aiming to provide reference for prevention of imported COVID-19 cases under regular prevention and control of COVID-19. MethodsA retrospective field epidemiological investigation was conducted to collect information of basic characteristics， illness onset， diagnosis， treatment， clinical manifestations， exposure history and risk factors within 14 days before onset， close contacts， close contacts of close contacts， and key places related to activity trajectories. Respiratory tract specimens of cases and contacts were collected for detection of SARS-CoV-2 by real time RT-PCR （rRT-PCR）. Emergency response， including infection source analysis and contact management， was conducted. ResultsThe case developed pharyngeal itch on July 28， 2021， and fever on the 30th， and went to the hospital for treatment twice on the 31st. Because his specimen was positive for SARS-CoV-2 by rRT-PCR on August 1， he was isolated and treated on August 2 and diagnosed as a confirmed case of COVID-19. The case was a foreign airline cargo service member at an international airport. The two regular nucleic acid screenings of him as a high-risk occupation on July 21 and 28 were negative. He did not leave Shanghai within 14 days before the onset of illness. During July 22nd and 23rd， he was repeatedly exposed during work to the high-risk environment that may have been contaminated by SARS-CoV-2 and had contact with the crew of foreign airlines， and the personal protection was not standardized. None of the 67 close contacts and 567 close contacts of close contacts in Shanghai showed symptoms during the 14-day medical quarantine， and the specimens of them were all negative for SARS-CoV-2 by rRT-PCR. The results of genome sequencing analysis showed that the genomic homology between the virus of the case and the one of recent domestic local epidemic and the recent imported cases was low， and the homology with the overseas Delta mutant strain was higher than that of the domestic Delta mutant strain. ConclusionThe situation of prevention of COVID-19 import is still serious. It is necessary to conduct regular nucleic acid screening for high-risk occupational groups， strengthen the diagnosis and reporting awareness of medical institutions， effectively implement the prevention and control measures for people， objects， and environment at international airports， and further enhance the public's awareness of personal protection.

ObjectiveTo investigate an outbreak of norovirus diarrhea in a welfare home for the elderly in Shanghai， and to analyze the epidemiology and virus genotype characteristics of the epidemic， thus providing a scientific basis for the prevention and control of norovirus epidemic. MethodsCase definition was clarified. After case definition， a standardized questionnaire was used to carry out case investigation to make comprehensive analysis in combination with field epidemiological investigation and laboratory tests results. ResultsThe epidemic lasted for 14 days， and 23 cases were reported with an incidence rate of 12.37% （23/186）， including 3 males and 20 females. There were more cases on the 1st， 4th and 6th floor of the main building in the welfare home， accounting for 52.17% （12/23） of total cases. 19 cases were reported in the main building， with an incidence rate of 11.59% （19/164）； 4 cases were reported in the auxiliary building， with an incidence rate of 18.18% （4/22）. There was no significant difference in the morbidity between the main building and the auxiliary building （χ²=0.779，P>0.05）. The main clinical manifestations were vomiting and diarrhea. There was a significant difference in the incidence of vomiting symptoms among the elderly， nursing staff and other staff in the welfare home （χ²=10.216， P<0.05）. But there was no significant difference in the incidence of diarrhea among the elderly， nursing staff and other staff （χ²=1.218， P>0.05）. Fecal samples were collected from 23 cases， 1 case family member， 68 risk personnel and 14 environmental surface swab samples. Norovirus GⅡ was detected in stool samples of 19 cases， 1 family member and 36 risk personnel. ConclusionOutbreak of norovirus infection is reported in a welfare home in Shanghai. The close contact between the elderly and health workers might lead to the outbreak.

Objective:To analyze the epidemiological characteristics of a cluster of 5 confirmed COVID-19 cases related with the transmission in incubation period of initial case, and find out the infection source and transmission chain.Methods:According to "The Prevention and Control Protocol for Coronavirus Disease 2019 (Third Edition)" issued by the National Health Commission, a field epidemiological survey was conducted for the 5 cases in January 2020. Nasopharyngeal swabs and sputum samples were collected from them for the detection of 2019-nCoV by real time RT-PCR. Multi prevention and control measures were taken, such as tracking and screening close contacts, medical isolation observation, investigating the epidemiological link, analyzing transmission chain.Results:Case 1, who had common environmental exposure with other COVID-19 cases, got sick on 20 January, 2020 and was confirmed on 1 February. Case 2 became symptomatic on 22 January and was confirmed on 27 January. Case 3 got sick on 25 January and was confirmed on 30 January. Case 4 had illness onset on 20 January and was confirmed on 1 February. Case 5 got sick on 23 January and was confirmed on 31 January. Among the 5 cases, case 2 died and the illness of other cases were effectively controlled. After exclusion of other common exposure factors, case 1 had a 6-hour meeting with case 2 and case 3 on 19 January. Case 2 and case 3 might be infected by case 1 during the incubation period. It is the key point for epidemiological investigation.Conclusion:The epidemiological investigation indicates that the transmission might occur in the incubation period of COVID-19 case, close attention should be paid to it in future COVID-19 prevention and control.

Objective:To analyze the epidemiological characteristics of imported COVID-19 cases in early phase in Shanghai, introduce measures and provide reference for prevention and control of imported COVID-19 cases.Methods:Data of imported COVID-19 cases in Shanghai reported as of 30 March, 2020 were obtained from National Notifiable Disease Report System of China CDC and field epidemiological investigation reports by CDCs in Shanghai. The information about measures of prevention and control was collected from official websites and platforms of the governments. Data cleaning and statistical analysis were performed with softwares of EpiData 3.1, Excel 2019 and SAS 9.4.Results:A total of 171 imported COVID-19 cases had been reported as of 30 March, 2020 in Shanghai, including 170 confirmed cases and 1 asymptomatic infection case. Among them, cases of Chinese nationality accounted for 71.3% (122/171) and cases of foreign nationality accounted for 28.7% (49/171). The median age of the cases was 23 years ( P 25, P 75: 18, 35 years), and the male to female ratio of the cases was 1.3∶1. Students accounted for 56.6% (97/171). About 45.6% (78/171) of the cases fell ill before arriving in Shanghai. The cases with mild or common clinical manifestation accounted for 96.5% (165/171) and no significant difference in clinical type was observed between overseas Chinese cases and foreign cases. The epidemic curve by diagnosis date reached peak on March 24, and the number of the cases gradually declined due to the closed-loop management process of joint port prevention and control mechanism. The 171 imported COVID-19 cases were mainly from 24 countries and regions, including the United Kingdom (64 cases, 37.3%), the United States (32 cases, 18.6%), France (19 cases, 11.0%) and Italy (16 cases, 9.4%). About 40.4% of the cases (69/171) planned to continue travelling to 21 other provinces and municipalities in China. Customs quarantine and community observation/detection points identified 43.9% (75/171) cases and 31.0% (53/171) cases, respectively. Conclusions:The imported COVID-19 cases in early phase in Shanghai were mainly young population and students accounted for high proportion. The imported risk of COVID-19 was consistent with the severity of the epidemic in foreign countries. The closed-loop management model of the joint port prevention and control mechanism plays an important role in the identification and management of the imported COVID-19 cases.