Objective: To investigate the epidemiological characteristics of 45 norovirus clusters in Baoshan District, Shanghai Municipality from 2019 to 2021, so as to provide the evidence for improving the management of norovirus clusters. Methods: The epidemiological characteristics and laboratory testing of 45 norovirus clusters were collected in Baoshan District from 2019 to 2021, and the temporal distribution, population distribution, distribution of places of norovirus clusters, clinical manifestations, laboratory testing results, origin of norovirus infection and transmission routes of norovirus clusters were analyzed using a descriptive epidemiological method. Results: A total of 45 norovirus clusters involving 29 379 individuals were reported in Baoshan District from 2019 to 2021, and 435 cases with norovirus infections were identified, with an average attack rate of 1.48%. Norovirus infection most often occurred from November to April of the following year, and the infection predominantly occurred among students (408 cases, 93.79%). There were 25 norovirus clusters in kindergartens (55.56%), 18 clusters in primary and middle schools (40.00%), one cluster in a social care facility and one cluster in a geriatric ward. Vomiting was the predominant clinical symptom (416 cases, 95.63%). The positive rate of norovirus was 37.35% in 597 samples. There were 40 norovirus clusters caused by the norovirus GⅡ genotype (88.89%), and the median duration of the norovirus cluster was 6 days (interquartile range, 1 day). In addition, 82.22% of the norovirus clusters reported to centers for disease control and prevention within 1 day,and 88.89% of the clusters were transmitted through human to human transmission or vomitus of cases. Conclusion The norovirus clusters predominantly occur in winter/spring and among students in Baoshan District from 2019 to 2021. Kindergartens and primary and middle schools are main places of norovirus infections, and the norovirus GⅡ genotype is the main type of pathogens. Human-to-human transmission and exposure to patients' vomitus are the main routes of transmission.

Objective: To investigate the epidemiological characteristics of cluster vomiting diarrhea outbreaks caused by Sapovirus infection in Baoshan District, Shanghai, and to provide reference for the standardized management of cluster vomiting diarrhea events in schools. Methods: The cluster of vomiting and diarrhea outbreaks in Baoshan District from 2017 to 2019 were collected, and the basic information and scene of each cluster were summarized. Sample results were collected and descriptive epidemiological methods were used to analyze the epidemiological characteristics of the outbreak. Results: From 2017 to 2019, a total of 100 cluster vomiting and diarrhea events were reported in Baoshan District, including 9 cases caused by Sapovirus, 120 cases of cluster vomiting diarrhea caused by Sapovirus, with an average incidence rate of 2.37%, including 39 laboratory confirmed cases, the epidemic epidemic time was mainly concentrated in September to November, the places were distributed in 4 primary schools and 5 kindergartens, the main clinical manifestations were vomiting (112/120, 93.33%), abdominal pain (27/120, 22.50%), diarrhea (26/120, 21.67%), compared with Norovirus events, the positive rate, vomiting and fever ratios of Zarovirus were lower than those of Norovirus( χ 2=8.32, 4.52, 14.20, P <0.05). Conclusion In school cluster vomiting and diarrhea events, the positive detection rate of Sapovirus is second enteric vinus behind Norovirus, and it s recommended to formulate a prevention and control plan for Sapovirus infection diarrhea to provide a basis for the on site treatment of school cluster vomiting diarrhea events.

Objective: To describe the clinical features, causal agent and transmission mode of a fever outbreak in a school in Shanghai. Methods: Field epidemiological approaches including case definition development, searching for contacts, distribution of diseases description, environmental sampling and laboratory testing. Results: A total of 16 influenza like cases were included, all concentrated in the one class of grade two, including 15 students and 1 teacher. Among student cases, the incidence rate was 36.59% (15/41), the average age was 7.4 years, the incidence rate was 36.84%(7/19) for boys, 36.36%(8/22) for girls. The clinical course was 5-15 days, with the median of 9 days, and 18.75%(3/16) of the cases stayed studying while sick. The nasopharyngeal swab specimens in 16 cases all tested positive for influenza B, of which 11 tested positive for mycoplasma pneumoniae and 1 case also tested positive for coronavirus OC43. Body temperature, number of mononuclear cells, and treatment time of patients infected with Influenza B and mycoplasma pneumoniae were higher than those of patients infected with influenza B alone( P <0.05). The outbreak lasted for 12 days, all sick students were treated and discharged from hospital, with no severe cases or death, and the outbreak was effectively controlled. Conclusion This campus cluster outbreak caused by influenza B and mycoplasma pneumoniae. Patients with influenza B with mycoplasma pneumoniae have severe symptoms and a long course of illness, suggesting the importance of early management of the epidemic.

Objective To investigate the cause and related risk factors of an outbreak caused by Brucellosis. Methods Epidemiological investigation and laboratory test were carried out among occupationally invloved population including sheep slaughters and sellers in the village. Results 18 people were serology positive among the 129 occupationally involved persons under survey. Seven of them were confirmed cases,11 were latent infection,to make the overall attack rate as 14%. 90%of the sheep were from high-risk areas of Brucella. Among the occupationally involved persons,89%of them never wore face masks,84%never wear overalls and 70%never wear gloves. Factors as:work but wearing no gloves(RR=7.4,95%CI:1.1-53.0),with hand wound(RR=3.4,95%CI:1.1-11.0) could increase the risk of Brucella infection. Conclusion The cause of this outbreak was due to the plentiful influx of unchecked sheep from the northern part of China and the employees in the process of sheep slaughtering or trading were lack of effective prevention programs.

ObjectiveTo ascertain the causes of a food poisoning incident and provide references for the prevention of similar incidents in the future. MethodsCase investigation was conducted through field epidemiological investigation methods， and suspicious meals and foods were searched by the analytical epidemiological method. A food hygiene investigation was conducted in the establishment involved and samples of suspicious food， processing steps， and cases were collected for laboratory testing. ResultsA total of 91 individuals meeting the case definition were identified， resulting in an attack rate of 14.97% （91/608）. The main clinical manifestations included abdominal pain （97.80%）， diarrhea （84.62%）， nausea （62.64%）， vomiting （72.53%）， fever （12.09%）， and increased white blood cells （90.11%）. The peak incidence occurred from 16：00 to 18：00 on June 15. The epidemic curve showed a point-source exposure pattern， with an incubation period of 1 h minimum and 10 h maximum， and an average of 5 h. Analytical epidemiological studies indicated that lunch on June 15 was the suspicious meal （χ²=38.78， P<0.001）， and those who consumed cold-dressed tofu with preserved eggs had a significantly higher risk of falling ill compared to non-consumers （χ²=105.21， P<0.001）. Laboratory testing results revealed Vibrio parahaemolyticus detected in 1 employee’s anal swab and 18 cases’ anal swabs. Staphylococcus aureus was detected in 1 food ingredient and 1 case’s anal swab. The remaining samples tested negative. ConclusionThe cause of this food poisoning incident is Vibrio parahaemolyticus. The cause is the canteen’s supply of cold-dressed tofu with preserved eggs beyond its permissible business scope， potentially leading to cross-contamination during food processing. Regulatory authorities should strengthen routine law enforcement inspections and monitoring. Food service establishments should strengthen food safety awareness， standardize operational procedures in strict accordance with relevant national laws and regulations and food safety standards， and strive to reduce the occurrence of foodborne disease incidents at their source.

OBJECTIVETo investigate the cause and related risk factors of an outbreak caused by Brucellosis.

METHODSEpidemiological investigation and laboratory test were carried out among occupationally invloved population including sheep slaughters and sellers in the village.

RESULTS18 people were serology positive among the 129 occupationally involved persons under survey. Seven of them were confirmed cases, 11 were latent infection, to make the overall attack rate as 14%. 90% of the sheep were from high-risk areas of Brucella. Among the occupationally involved persons, 89% of them never wore face masks, 84% never wear overalls and 70% never wear gloves. Factors as:work but wearing no gloves (RR = 7.4, 95%CI:1.1-53.0), with hand wound (RR = 3.4, 95%CI:1.1-11.0) could increase the risk of Brucella infection.

CONCLUSIONThe cause of this outbreak was due to the plentiful influx of unchecked sheep from the northern part of China and the employees in the process of sheep slaughtering or trading were lack of effective prevention programs.

Abattoirs ; Animals ; Brucella ; isolation & purification ; Brucellosis ; epidemiology ; China ; epidemiology ; Commerce ; Disease Outbreaks ; Humans ; Incidence ; Occupational Diseases ; epidemiology ; Risk Factors ; Sheep ; microbiology