Study On Epidemic Characteristics And Risk Factors Of Typhoid And Paratyphoid In Hongta District In Yuxi City

ObjectiveTo investigate the reasons for the high incidence rate of Typhoid and Paratyphoid and risk factors of the Typhoid and Paratyphoid in Hongta district in Yuxi city,to drafting the targeted intervention measures of Typhoid and Paratyphoid and providing basis for control measure.MethodsIn the district of highest incidence rate of Typhoid and Paratyphoid in our country(Hongta district of Yuxi city in Yunnan province) we developed the cross-sectional investigation(the diet and water sanitation and the awareness rate of typhoid and paratyphoid of the public etc.),the case interview,the case-control study and the ecological investigation.We adopted the stratified random sampling in the diet and water sanitation of the cross-sectional study,and sampled and invested a certain number of tableware and drinking water of the city and villages.We interviewed the part of the cases and established the preliminary hypothesis,1:1 matched case-control studies were adopted.Descriptive analysis studies were adopted.The cases newly diagnosed in 2008 were carried out the epidemiology investigated,and finding the possible risk factors.According to the risk factors of the case-control studies and the geographical distribution of the characteristics of the cases,we developed the environment risk factors investigation in the communities of high incidence rate and low incidence rate. Adopting the uniform survey program,the investigators had received uniform training. Face-to-face interviews were carried out to the cases and the control people.In the ecological study we mainly investigated the environment of the restaurants,the purchase vegetables places,the processing methods of the raw vegetables and adopted PCR detection method detecting the pollution condition of Typhoid and Paratyphoid of the samples.The completed questionnaires were checked and inspected,all questions were uniformly recorded the computer and the database was established and were checked and inspected.All statistical analysis was processed in software of Excel,EPI-INFO 2002 and SAS 9.1.Adopting descriptive analysis,the case-control study including the group analysis,individual matching analysis,the condition Logistic regression of single factor and multiple factors.Result1.Epidemical characteristics of typhoid and paratyphoid in Hongta district in Yuxi city.The incidence rate of typhoid and paratyphoid suddenly rose in 2001 and the increased rate of city higher than the increased rate of the villages(19.87 and 15.52 times).2001-2008,the incidence rate fluctuated at higher level of incidence rate of the disease,the low incidence was rising trend year by year.The city incidence was significantly higher than urban township areas,the average incidence rate of the disease of the city proper was 4.60 times higher than the villages and towns.The high incidence of the year was 2001,2004,2006,2007,the average incidence rate of the disease of the city proper was followed by 4.15 times,4.99 times,4.40 times,4.68 times higher than the villages and towns.Typhoid and paratyphoid occurred throughout the year and May-October were the mostly common months for infection of this pathogen,one peak(May-August) appeared generally and two peaks (April-May and August-October) appeared in the part of the years.The main pathogeny of typhoid and paratyphoid was salmonella paratyphi A(99.33%).And any age and either sex may contract typhoid and paratyphoid,the young people and the students were mostly commonly affected.The gender difference wasn't evident.The incidence of the disease of the staff member of the enterprises in the center city proper (408.30 per 100 thousands) was higher than the residents of the villages and towns (87.90 per 100 thousands).Farmers,students and workers were the emphasis crowd. The average incidence rate of occupation was followed by teachers(532.96 per 100 thousands),workers(465.00 per 100 thousands),medical staff(364.94 per 100 thousands),students(364.92 per 100 thousands)and the personnel waiting for a job(288.00 per 100 thousands),The average incidence rate of the farmers was only 103.59 per 100 thousands(11 bit).The average incidence rate of the cadres of staff was 115.12 per 100 thousands(10 bit).2.Risk factors of typhoid and paratyphoid in Hongta district of Yuxi city.2.1 The cross-sectional investigation analysis:The Hongta district of Yuxi city lies in the middle of Yunnan province,the economic is better.The food or beverage industry investigate showed that the qualified rate of tableware in the city(69.40%) was less than the rate of the villages and towns(73.30%) by the statistical test(x~2=7.56,P＜0.05).The qualified rate of the drinkable water of the city and the villages was 95.40%and 47.90%,by the statistical test(x~2=53.93,P＜0.05).The awareness rate of typhoid and paratyphoid of the public was 35.92 per 100.2.2 The case-control study analysis:2.2.1 The completed pairs was 80 pairs.The Group analysis:we found that usually having lunch and supper at outdoor(OR=6.79,95%CI:2.81-16.84),within tow weeks, having the dinner at outdoor(OR=39.60,95%CI:13.76-120.38),having breakfast adding health corianders and health mints(OR=5.53,95%CI:1.73-18.75),having cold dishes at outdoor within tow weeks(OR=4.28,95%CI:1.73-10.75),having cold dishes adding health corianders and health mints(OR=3.43,95%CI:1.27-4.43) and corn mint(OR=10.02,95%CI:2.95-36.21) at outdoor.Having health corianders and health mints would increase the dangerous of infection of typhoid and paratyphoid and frequency of having dinner had dose response relationships.The individual matching analysis:within tow weeks,having breakfast adding health corianders and health mints,having cold dishes at outdoor within tow weeks,dip food adding health corianders and health mints,three factors were statistical significance and may be the risk factors.2.2.2 Conditional Logistic regression analysis of single factor and multiple factors, showed:single factor conditional Logistic regression analysis:in the 22 factors,eight factors was meaningful in statistics:usually having lunch and supper at outdoor, within tow weeks,having dinner at outdoor,having breakfast adding health corianders and health mints,having cold dishes at outdoor,having cold dishes adding health corianders and health mints at outdoor,dip food adding health corianders and health mints,were very meaningful in statistics.Using conditional Logistic regression of multiple factors,adopting step-by-step method screening variables(sle=0.15,sls=0.10), we found that having breakfast adding health mints,having cold dishes at outdoor, dip food adding health corianders and health mints were risk factors in Hongta district.2.3 Environment Ecological study analysis:2.3.1 Studying the purchase vegetables places and the related environment risk factors of three high incidence communities and three Low-fat communities.The purchase vegetables places,prepared dishes time,water,the processing methods of raw vegetables of the restaurants of the high incidence communities and the Low-fat communities,the investigation analysis:the restaurants of the high incidence communities purchased vegetables in Yaotou market(x~2=5.43,P=0.02＜0.05).There was a no protection well in the Yaotou market.The vendors washed and kept fresh vegetables using the water from the well.The health corianders and health mints were kept too long and weren't cleaned out in the restaurants,prepared dishes(raw vegetables) time of the high incidence communities and the Low incidence communities was 2.79 and 0.42 hours.2.3.2 PCR detection method:Health corianders(182 copies),health mints(182 copies),the sewage(37 copies),the river(27 copies),the well(13 copies),the fresh water(77 copies),the investigation analysis:the salmonella positive 2 copies,one copy fresh water(from the well of Yaotou market),health corianders(from the restaurant where the case had dinner) detected the salmonella,in the investigation,we couldn't depart the typhoid and paratyphoid strains,the salmonella positive of the sewage(5 copies),the salmonella positive of the river(4 copies),the salmonella paratyphi A positive of the river(3 copies),The 66 samples of the prepared dishes(health corianders and health mints) in the restaurants,the detection results:the number of coliform(≥24000MPN/100g),due to the food had no standard of the state,reference the drinking water health standards(GB/T5750-2006),the samples all exceeded the standard.The environmental sewage investigation:Specific hospitals existed the situation that the waste water that no harmless processing.The sewage channels passed through the residential areas and field.The farmers generally irrigated the field using the sewage.Conclusions1.This study indicates that typhoid and paratyphoid had been at the peak period of prevalence since 2000 in Hongta district and related to the increased incident rate of the city morbidity.2.The reasons for the high-fat were related to the raw vegetables production and processing,the sanitation of the sales links in the food or beverage industry,and the eating customs of the residents.The investigation analysis:having cold dishes at outdoor,having food adding health corianders and health mints.The frequency of having dinner had dose response relationships.The pollution of raw vegetables (health corianders and health mints) was related to the irrigating using the sewage and fresh the vegetables using the unclean fresh water.3.There were sanitation problems in the food or beverage industry.The qualified rate of tableware in the city was less than the villages and towns,the sanitation problems would be improved.4.This study indicated:The Hongta district of Yuxi city's economic is better,the epidemic situation of typhoid and paratyphoid for the pollution caused by food-borne was a major public health problem in Hongta district.Proposing strengthen health supervision to the production,processing,keeping,sales links of the raw vegetables (health corianders and health mints),and when necessary adopting the methods limiting to eat raw vegetables(health corianders and health mints) at some stages to lower the incidence rate of the disease,prohibiting using the sewage to water and clean the vegetables.Increasing the propaganda and edution of the masses and improving the awareness of prevention diseases.