| Background:Diarrhoea is a global problem for public health.It is one of the leading causes of morbidity and mortality among children aged under five.China is one of 15 high-burden countries for diarrhoea in the world,but there’s little prospectively conducted studies at home and considerable data gaps exist regarding issues like the etiological spectrum and burden of diarrhoeal diseases.Objectives:To explore the etiological spectrum of diarrhoea for three age groups,namely children aged under five,ages 5-44 years and ages over 45;to describe seasonal pattern and annual trends of major enteropathogens;to estimate incidence rates and outpatient rates for diarrhoeal diseases;and to assess the effectiveness of existing interventions and help the development and recommendations of vaccines.Methods:1.Active surveillance of diarrhoeal diseases were conducted in outpatient and/or emergency departments of 181 sentinel hopitals at China since 2009.Demographic,clinical and epidemiological data of diarrhea case-patients were cellected systematically.Fecal specimens were also collected and sent to 117 network-laboratories to test for presence of 13 enteropathogens,including 5 viruses and 8 bacteria.The microbiological findings and data from case-patients in 2009-2013 were analysed by descriptive epidemiological methods.Etiological spectrums of diarrhoea for different age groups were showed by calculating proportions.Annual trends of major enteropathogens were studied by using generalized linear mixed effects models.Seasonal patterns of enteropathogens were explored by fitting monthly prevalence of enteropathogens to periodic linear regression models.2.To estimate the burden of diarrhoeal diseases,active surveillance of diarrhoeal diseases was carried out in 11 sentinel hospitals from 2012 to 2013 at Pudong New District,Shanghai Prefecture,China.To help evaluate the representativeness of sentinel hospitals,Hospital Utilization and Attitudes Survey(HUAS)was conducted among community members and catchment population of sentinel hospitals were calculated.Incidence number and hospitalization number of diarrhoea were acquired by extracting registry data from Hospital Information System(HIS)of hospitals,but after a thoroughly evaluation of completeness and accurateness of extracted data through comparing of HIS data with surveillance data collected at intestinal clinics of sentinel hospitals.The Monte Carlo models were developed to estimate rates of diarrhoeal diseases and the uncertainty of estimates,by using enteropathogen prevalence,catchment population of hospitals and counts of diarrhoea in hospitals as primary model inputs.Results:1.Among 87578 enrolled outpatient diarrhoea case-patients collected from 181 sentinel hospitals between years 2009-2013,26585 cases were tested positive.All 13 enteropathogens were detected.Rotavirus was the most common detected enteropathogen among children aged under 5,with 32.4%of children tested positive for the agent.Norovirus was the second common enteropathogen among children aged under 5 and the leading enteropathogen among adults,with 10.8%of cases identified with norovirus.Diarrhea-genic Escherichia coli(DEC),Non-typhoidal Salmonella spp(NTS)and Shigella spp were the three leading bacterial pathogens among outpatient diarrhoea case-patients,with 5.9%,3.8%and 3.3%of cases tested positive,respectively.Vibrio parahaemolyticus and Aeromonas spp were two regional prevalent enteropathogens,which were most common among coastal provinces.A strong seasonal pattern was observed for several enteropathogens,including rotavirus(winter),norovirus(autumn),and bacterial pathogens(summer).The annual trends of enteropathogens showed that,the prevalence of Shigella spp has droped year by year,decreased from 10.2%in 2009 to 1.4%in 2013.While the prevalence of DEC has rised sharply,increased from 2.9%in 2009 to 10.1%in 2013.2.The hospitals set up in the active surveillance study of diarrhoea in Pudong New District has covered 1.723 million populations,accounting for 29.2%of general populations in the catchment area.From surveillance year 2012 to 2013,408 thousand records of diarrhoea outpatient and emergency departments visits(accounting for 1.8%of total outpatient/emergency department visits)and 3688 records of diarrhoea hospitalization(accounting for 0.8%of total hospitalizations)were extracted from 10 sentinel hospitals’s HIS system.3847 diarrhoea cases(accounting for 0.9%)were recruited and tested for 13 enteropathogens at network laboratories,of which 1757(45.7%)cases tested positive.The most commonly detected pathogens were norovirus(19.9%of cases),DEC(7.6%)rotavirus(7.3%),NTS(5.3%)and Vibrio parahaemolyticus(2.7%).The estimated annually episodes of diarrhoea in Pudong New District was 2.854 million and the incidence rate was estimated at 0.483 episodes/person year(90%UI:0.22-0.98 episodes/person year).The estimated annually outpatient and emergency department visits of diarrhoea in Pudong New District was 0.508 million and the rate of outpatient visits was estimated at 0.086 episodes/person year(90%UI:0.050-0.158 episodes/person year).Approximately 44.1%of diarrhoea outpatient visits in Pudong were caused by 5 enteropathogens,namely norovirus,DEC,rotavirus,NTS and Vibrio parahaemolyticus.Among them,norovirus had the highest incidence number and outpatient visits for general population of Pudong New District.The estimated incidence rate was 0.097 episodes/person year and outpatient rate was 0.017 episodes/person year;DEC had the second highest incidence rate and outpatient rate,estimated at 0.043 and 0.007 episodes/person year,respectively;rotavirus had the highest incidence rate and outpatient rate among children aged under 5,estimated at 0.085 and 0.038 episodes/child year,respectively;NTS was the second most common bacterial pathogen,which had an incidence rate of 0.025 episodes/person year and an outpatient rate of 0.005 episodes/person year;and Vibrio parahaemolyticus was the important enteropathogen among population 5-44 years old.The estimated incidence rate was 0.025 episodes/person and the outpatient rate was 0.003 episodes/person year.Conlusions:The etiological spectrum of diarrhoea in China was very similar to that of other developing countries.All the 13 enteropathogens were detected among outpatient diarrhoea case-patients in our study.Five enteropathogens,namely rotavirurs,noovirus,DEC,NTS and Shigella spp,had caused most of the diseases.Interventions targeted on those 5 diarrhoeal diseases could effectively reduce the burden of diarrhoea.China should included rotavirus vaccines into national immunization programmes as soon as possible,based upon a comprehensive evaluation of the incidence frequency,severity and economic burden of the illness.Norovirus,DEC,NTS and Shigella spp were all important food-borne illnesses.To help control those diseases,further studies,like food outbreaks investigation and food attribution studies should be conducted.A strong seasonal pattern was observed for several enteropathogens,including rotavirus(winter),norovirus(autumn),and bacterial pathogens(summer).This knowledge of seasonality for enteropathogens was very useful when planning and implementing diseases control and prevention programmes.It was also useful in exploring environmental factors(like ambient temperature,precipitation and humidity)that driven for the seasonality of enteropathogens.Our study showed that the diseases burden of infectious agents could be estimated through sentinel-based active surveillance study,which is the most commonest type of study in present China.This study had provided a possible approach for conducting diseases burden studies at China in future. |
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