| Objective:To analyze the epidemiological characteristics and incidence trend of hepatitis E in Beijing from 2005 to 2020,so as to provide scientific basis for the prevention and control of hepatitis E in Beijing.To explore the risk factors of hepatitis E infection in Beijing and put forward countermeasures.Methods:1.Descriptive epidemiological method was used to analyze the epidemiological trend of hepatitis E in Beijing from 2005 to 2020,and the differences in the reported incidence rates in different time periods and regions were compared.2.Case-control study on the risk factors of hepatitis E.The cases were from the confirmed hepatitis E cases reported in Beijing Infectious disease Reporting Information management system from January 2022 to December 2022.Controls were drawn from the general community population.A case-control questionnaire,the Risk factors questionnaire for sporadic hepatitis E,was developed.A 1:1 matched case-control study was conducted to investigate all the included cases and controls by telephone.According to the time of onset of the cases,the telephone survey was conducted in chronological order.The cases and controls should be investigated by the same investigator and at the same time.The questionnaire included the general information and dietary hygiene habits of the cases and controls.The survey of risk factors mainly included the dietary habits 15～45 days before the onset,whether often eating out(including eating in restaurants or takeaway)and history of going out,and hepatitis E vaccination status.3.Collection of pig liver samples From July to September2022,a total of 290 pig liver samples were randomly collected from pig liver sales outlets in 16 districts of Beijing,including large supermarkets,wet markets,fresh supermarkets,fresh meat shops,farmers’markets and small stalls.After sample processing,HEV RNA was qualitatively detected by real-time PCR.?2 test was used to compare the difference of HEV RNA positive rate among different regions,types of procurement sites and monovalent HEV infection,and the test level wasα=0.05.MEGA7.0 and Clustal Omega software were used to sequence the PCR products of positive samples,and the gene sequences of representative HEV strains of different genotypes were searched from Gen Bank as reference sequences.According to the HEV gene sequence alignment and phylogenetic tree analysis,the genotype of swine HEV detected in this study was determined.Results:1.From 2005 to 2020,a total of 6145 cases of hepatitis E were reported in Beijing,and the average annual reported incidence was 1.92/100 000.The reported incidence showed a downward trend(trendχ~2=1089.1,P<0.001).The concentration ratios of hepatitis E were between 0 and 30,indicating that the seasonality of hepatitis E in Beijing was weak or poor.The time was divided into four periods:2005-2008,2009-2012,2013-2016 and 2017-2020,and the average incidence of each period showed a downward trend over time(χ~2=787.7,P<0.01).From 2005 to 2020,Chaoyang district,Haidian District and Fengtai district were the top three districts with the highest number of reported hepatitis E cases.The average annual incidence was 2.32/100 000,1.41/100 000 and 1.73/100 000 in urban,suburban and outer suburbs,respectively.The incidence was higher in urban area than in suburban and outer suburbs.The incidence of hepatitis E increased with age,and there was a linear trend(trendχ~2=3441.7,P<0.01).The number of cases in 50-59 age group was the highest(1624 cases),accounting for 26.43%of the total number of cases.From 2005 to 2020,the reported cases and annual incidence rates were higher in males than in females(χ~2=1028.4,P<0.01),and the ratio of male to female was 2.4:1.The top three occupations and the number of cases were retired workers(1914,31.15%),cadres and workers(1059,17.23%),and household workers or unemployed(931,15.15%).2.This survey investigated 58 cases in the case group and 58 cases in the control group,including 41 pairs of males,accounting for 70.69%.There were 17 female pairs,accounting for 29.31%.The male to female ratio was 2.41:1.In this study,the youngest was 24 years old,the oldest was77 years old,and the average age was 54.03±12.21 years old.The age of the cases was mainly over 40 years old,accounting for 37.93%of the total cases.Most of the cases were retired workers(18 cases,31.03%),followed by housework and unemployed(11cases,18.96%).There was no significant difference in occupational distribution between the case group and the control group(P=0.866).By rank sum test,there was no significant difference in education level between the case group and the control group(U=1940.5,P=0.136).Multivariate analysis showed that the frequency of eating shabu or roast meat and the frequency of eating out 15 to 45 days before the onset of hepatitis E were risk factors for the onset of hepatitis E,with P values less than 0.05.3.A total of 290 pig liver samples were randomly purchased from pig liver sales points in 16 districts of Beijing for HEV RNA detection.Six positive samples were detected,including 1 from Dongcheng,2 from Tongzhou,1 from Changping,1 from Daxing and1 from Miyun,and no positive samples were detected in other regions.The total positive rate of HEV RNA was 2.07%(6/290).The positive rate of HEV RNA in pig liver samples from different regions was statistically different.Sequence comparison showed that the five newly isolated HEV strains were all type 4,and were distributed in two subtypes 4a and 4d.The nucleotide sequences of the 189bp fragment in ORF2region of five HEV strains were compared,and the homology was found to be between86.7 and 98.9%.The homology between pig HEV and human HEV and reference strains ranged from 81.4 to 100%,and the homology between E-3 and BJ101 and BJ102strains in HEV patients was as high as 100%.Conclusion:1.The incidence of hepatitis E in Beijing showed a downward trend from2005 to 2020,indicating that the current prevention and control measures for hepatitis E were effective.It is necessary to continue to monitor hepatitis E in the city and promote the vaccination of high-risk groups,mainly the elderly.2.Frequent eating out,seafood,fresh river and pig liver are the risk factors of hepatitis E.Measures should be taken to strengthen the safety management of food and water sources,change people’s bad eating habits and other measures to prevent hepatitis E infection.3.The results of this study supported that the liver of infected pigs and commercial swine with HEV infection was an important reservoir and source of HEV infection,which should be paid attention to.It is of public health significance to prevent faecal-oral route or foodborne... |
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