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Objective To investigate the current situation and influencing factors of latent tuberculosis infection(LTBI)among close contacts of positive etiology pulmonary tuberculosis(PTB)patients,provide basis for formula-ting intervention measures for LTBI.Methods A multi-stage stratified cluster random sampling method was used to select close contacts of positive etiology PTB patients from 39 districts and counties in Chongqing City as the study objects.Demographic information was collected by questionnaire survey and the infection of Mycobacterium tuberculosis was detected by interferon gamma release assay(IGRA).The influencing factors of LTBI were analyzed by x2 test and binary logistic regression model.Results A total of 2 591 close contacts were included,the male to female ratio was 0.69∶1,with the mean age of(35.72±16.64)years.1 058 cases of LTBI were detected,Myco-bacterium tuberculosis latent infection rate was 40.83％.Univariate analysis showed that the infection rate was dif-ferent among peoples of different age,body mass index(BMI),occupation,education level,marital status,wheth-er they had chronic disease or major surgery history,whether they lived together with the indicator case,and whether the cumulative contact time with the indicator case ≥250 hours,difference were all statistically significant(all P＜0.05);infection rate presented increased trend with the increase of age and BMI(both P＜0.001),and decreased trend with the increase of education(P＜0.05).Logistic regression analysis showed that age 45-54 years old(OR=1.951,95％CI:1.031-3.693),age 55-64 years old(OR=2.473,95％CI:1.279-4.781),other occupations(OR=0.530,95％CI:0.292-0.964),teachers(OR=0.439,95％CI:0.242-0.794),students(OR=0.445,95％CI:0.233-0.851),junior high school education or below(OR=1.412,95％CI:1.025-1.944),BMI＜18.5 kg/m2(OR=0.762,95％CI:0.586-0.991),co-living with indicator cases(OR=1.621,95％CI1.316-1.997)and cumu-lative contact time with indicator cases ≥250 hours(OR=1.292,95％CI:1.083-1.540)were the influential fac-tors for LTBI(all P＜0.05).Conclusion The close contacts with positive etiology PTB have a high latent infection rate of Mycobacterium tuberculosis,and it is necessary to pay attention to close contacts of high age,farmers,and frequent contact with patients,and take timely targeted interventions to reduce the risk of occurrence of disease.
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Objective To analyze the characteristics of urinary iodine and edible iodized salt,and to provide suitable iodine concentration in iodized salt.Methods Sample testing was carried out to detect iodine concentration in marketed salt and child urine before salt iodization (1994).After salt iodization (2001-2010),sample testing was carried out to detect salt iodine level in manufacture,market(2001-2010) and resident household(1997-2010).Urine of children aged 8 to 10 were sampled by PPS method from 1997 to 2005.In 2009,urinary iodine of 20 children was determined in each of 5 schools,which were sampled from 5 counties located at North,South,East,West and center of Chongqing.Based on the urinary iodine and salt iodine levels before salt iodization,the relationship of urinary iodine and consumption of iodized salt was calculated.Suitable iodine concentration in iodized salt was put forward.x2 test and trend analyze approach(F-test) were used for statistical analysis.Results Before salt iodization,salt iodine level was not tested in 204 edible salt samples; the median of urinary iodine was 53.14 μg/L in 1374 children.After salt iodization,form 2001 to 2010,the average iodine levels in manufacture and wholesale salt were between 29.72-36.25 mg/kg and 30.65-36.13 mg/kg,respectively,both of them decreased significantly(F =35.35,140.59,all P ＜ 0.01),and show a downward trend.Batch quality passing rate of industry iodized salt was 100％ except in 2001,which was 92.86％.Batch quality passing rate of market iodized salt were between 88.68％-99.77％,specifically in 2001 (88.68％),in 2002(92.57％) and in 2003 (96.22％).There was no significant difference in other years (all P ＞ 0.05).The median of urinary iodine were between 238.80-328.00 μg/L,more than 35％ fall into ＞ 300 μg/L; while salt iodine increased 1 mg/kg,urinary iodine increased 5.51 μg/L-7.40 μg/L; The medium of urinary iodine of children were between 140.05-383.00 μg/L in 40 counties or districts in 2009.Reducing the iodine concentration in edible iodized salt to 20 mg/kg,the median of urinary iodine can be kept at 163.34 μg/L to 201.14 μg/L.Conclusions Iodine in iodized salt is above sufficient in Chongqing.Salt iodine should be reduced to 20 mg/kg,which will meet various population's need.
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Objective To find out the current thyroid volume of school children and its influencing factors in Chongqing.Methods Probability sampling method(PPS) was used to select 30 counties in Chongqing in 2011.Forty children aged 8-10of 1 randomly selected school from every county chosen were enrolled in the study.Thyroid volume of children was examined by B-ultrasonograghy.Body height and body weight were measured.The relationship between gender,age,height and weight and thyroid volume was analyzed,respectively.Results One thousand three hundred and twenty-two children aged 8-10 were investigated.The median of thyroid volume was 3.53 ml.The goiter rate was 5.52％ (73/1322).Thyroid volume of female and male was 3.55 and 3.51 ml,respectively.There was no significant difference of thyroid volume between female and male (H =0.68,P ＞ 0.05).Thyroid volume of children aged 8,9 and 10 was 3.30,3.53 and 3.76 ml,respectively.There was a significant difference of thyroid volume among different age groups(H =52.49,P ＜ 0.01).Thyroid volume of children height (110-,120-,130-and ≥140 cm,respectively) was 2.96,3.22,3.59 and 4.13 ml.There was a significant difference of thyroid volume among different height groups (H =149.23,P ＜ 0.01).Thyroid volume of children weight(17-,20-,30-and ≥40 kg,respectively) was 2.71,3.31,3.91 and 4.74 ml.There was a significant difference of thyroid volume among different weight groups(H =138.44,P ＜ 0.01).For the coefficients of simple and partial correlation,there was a significant correlation between thyroid volume and age,height and weight (P ＜ 0.05).The Spearman coefficient was 0.2411,0.3950 and 0.4285,respectively.The partial correlation coefficient was 0.0640,0.1154 and 0.2319,respectively.The standard partial coefficient of age,height and weight was 0.640,0.1154 and 0.3410,respectively.The proportion of the standard partial coefficients was 1 ∶ 1.8 ∶ 5.3.The function of body weight to thyroid volume was 5.3 times that of age and 3.0 times that of body height.Conclusions The goiter rate of schoolchildren in Chongqing is relatively high.Thyroid volume is affected by age,body height and body weight.The relationship between thyroid volume and iodine nutrition needs further study.
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Objective To analyze the spatial distribution characteristics of non-iodized salt at household level based on geographic information system (GIS) in Chongqing.Methods The database of non-iodized salt at county level from 2001 to 2010 was established in Chongqing.By using GIS technology,the spatial distribution and spatial autocorrelation were analyzed by ArcGIS 9.3 software.Results The rate of non-iodized salt was fluctuated between 2.35％-5.78％ during 2001-2006 and the rate was reduced to less than 2.00％ after 2007.The result of spatial autocorrelation analysis on non-iodized salt from 2001 to 2006 indicated that Moran's Ⅰindex was 0.145578,0.078801,0.108033,0.091957,0.127749,0.214302,respectively(Z value was 3.066275,1.977321,2.541619,2.309972,2.900446,3.874203,respectively,all P ＜ 0.05).The spatial distribution of non-iodized salt had marked spatial cluster through Chongqing region from 2001 to 2006.The result of local spatial autocorrelation analysis from 2001 to 2006 indicated that Fengdu and Fuling were two high-risk areas(all P ＜ 0.05).Dianjiang,Yubei,Jiangbei,Wulong and Banan were also confirmed as high-risk areas in 2001,2005 and 2006(all P ＜ 0.05).The results also indicated that the distribution of non-iodized salt in the seven high-risk areas was positively correlated.The result of spatial autocorrelation analysis on non-iodized salt from 2007 to 2010 indicated that Moran's Ⅰ index was 0.018361,0.016186,0.040769,-0.059691,respectively (Z value was 1.093310,0.787361,1.071811,-0.583820,respectively,all P ＞ 0.05).The spatial distribution of non-iodized salt was at random on the whole from 2007 to 2010.However,there were four local high-risk areas.The distribution in Fengdu and Dianjiang was positively correlated,while that in Jiangjin and Shizhu was negatively correlated.Conclusions The distribution of non-iodized salt at households level in Chongqing is changed from spatial distribution before 2006 to random distribution after 2007,but there are high value areas,which should be taken as the focus of monitoring.
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Objective To monitor the quality changes of iodized salt and analyze its impact factor in Chongqing between 2001 and 2009. Methods Salt samples were collected according to the east, west, south,north and center locations in iodized salt production, wholesale and household sectors. Two units in iodized salt production and wholesale segment were sampled from north, south, east and west places and only 1 unit was sampled from the central place. Nine samples were collected every month in each place. If the place had less than 9 units, and then taken all the units. About resident household, 2 townships were sampled from north, south, east and west places, and 1 township was sampled from the central place, then 20 samples were collected from each township. Iodine content was detected by oxidation-reduction assay. The index of mean iodine, qualified rate from factories and wholesale, coverage rate and taking rate of qualified iodized salt in residents were calculated.Significance was analyzed by trend test, analysis of variance and X2 test. Results The qualified rate of iodized salt from the manufacturers was 92.9%(13/14) in 2001 and the rate was 100.0% each year from 2002 to 2009. The qualified rates of iodized salt from the wholesale were 88.7%(282/318) - 99.8%(431/432). The rates of 2001 and 2002 were lower than that of other years(X2 = 4.98 - 45.69, all P 90% kept increasing. The mean iodine from the manufacturers and wholesale were 29.71 - 36.25, and 31.26 - 36.13 mg/kg, respectively. The iodine level showed a descending trend(F = 35.45, 140.59, all P 0.05 ). The iodine level from manufacturers, wholesale to inhabitants showed an descending trend(F = 38.46 - 671.23, all P < 0.01 ). Conclusions The surveillance results of iodized salt shows an increasing tendency in quality of iodized salt, eoverage rate and taking rate of qualified iodized salt. Factors that affect the quality of iodized salt is that the enterprise does not add iodine to salt strictly by the standard.
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Objective To construct and express the recombinant plasmid pET28α-Sj26GST-Sj32 of Schistosoma japonicum(Sj) in Escherichia coli BL21 (DE3). Methods Total RNA was extracted from Sj adult worms by ultrasound-breaking, Sj26GST and Sj32 antigen gene was respectively amplified by RT-PCR from the total RNA; Sj26GST-Sj32 fusion gene obtained with gene splicing by overlap extension(SOEing) was cloned into prokaryotic expression plasmid pET28α and transformed into Escherichia coli BL2 (DE3) to construct pET28α-Sj26GST-Sj32;BL21 (pET28α-Sj26GST-Sj32) was induced with isopropyl-β-D-thiogalactopyranosid (IPTG), and the expressed products were analyzed and identified by sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE)and Western blotting. Results The 1991 bp Sj26GST-Sj32 fusion gene was successfully amplified by gene SOEing and cloned into pET28α by restriction analysis and PCR identification, the recombinant plasmid pET28α-Sj26GST-Sj32 was successfully constructed; the relative molecular mass of the expressed recombinant protein was approximately 69 × 103 by SDS-PAGE, and the amount of the expressed protein was 25% of the total bacterial proteins; the fusion protein could be recognized by sera from rabbits infected with Sj by Western blotting.Conclusions The recombinant plasmid pET28α-Sj26GST-Sj32 is successfully constructed and highly expressed in Escherichia coli in fused form with His-tag, and the expressed fusion protein shows specific antigenicity.
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Objective To investigate the nutritional status of iodine among residents in Chongqing, and to facilitate scientific prevention and control of iodine deficiency disorders. Methods Select 9 towns in each of the 40 districts (counties) in Chongqing, and collect 40 resident edible salt samples in each of the selected town to detect salt iodine by direct titrimetry. Select 5 towns on the site of the east, west, south, north and middle of every district (county), select 20 children aged 8 to 10 in each of the selected town to collect urine samples and detect urinary iodine by As-Ce catalytic spectrophotometric assay. Results The median of iodine of 14 217 salt specimens by household was 292 mg/kg with a coverage rate of qualified iodized salt of 98.90%( 14 061/14 217). The consumption rate of qualified iodized salt was 95.59%( 13 590/14 217). The median of urinary iodine for 4050 children aged 8 to 10 was 247.20μg/L, of which < 50 μg/L accounted for 4.60%(186/4050), 50-99μg/L accounted for 7.28% (295/4050), 100 - 199 μg/L accounted for 26.44% (1071/4050), 200 - 299 μg/L accounted for 25.58% (1036/4050), 300 μg/L or more, accounted for 36.10% (1462/4050). However, no significant difference was observed between different age groups(x2 = 3.77, P > 0.05). At district (county) level, the median of urinary iodine in 10(25.00%) districts (counties) was 100 - 200 μg/L, that in other 23(57.50%) districts (counties) was 200 - 300 μg/L, and that in other 7(17.50%) districts/counties was greater than 300 μg/L, and statistical significance was observed between different districts/counties (x2 = 441.95, P < 0.01). Conclusions Current iodine nutrition among residents in Chongqing is adequate. While there is excess, need to reduce the amount of salt iodization.
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Objective To construct and express the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum(sj)in Escherichia coli(E.coli)B121(DE3).Methods The total RNA was extracted from sj adult worms by ultrasound-breaking,Sj26GST antigen gene was amplified by RT-PCR from the total RNA,then cloned into prokaryotic expression plasmid pET32α(+) and transformed into E.coli B12(DE3)to construct pET32α-Sj26GST;BL21(pET32α-Sj26GST)WaS induced with isopropyl-β-D-thiogalactopyranosid(IPTG),and the expressed products were analyzed and identified by SDS-PAGE and Western blot.Results The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET32α(+)by restriction analysis and PCR identification,the recombinant plasmid pET32α-Sj26GST was successfully constructed;the relative molecular mass of the expressed recombinant protein was approximately 49×103 by SDS-PAGE,and the amount of the expressed protein was 24%of the total bacterial proteins;the fusion protein could be recognized by sera from rabbits infected with sj by Western blot.Conclusions The recombinant plasmid pET32α-Sj26GST is successfully constructed and highly expressed in E.coli in fused form with Trx-tag and His-tag,and the expressed fusion protein shows specific antigenicity.
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<p><b>OBJECTIVE</b>To investigate the changes in natural ecology and social environment after the construction of the dam in the Three Gorges Reservoir area, and to understand the social behavior status and education backgrounds of the local residents, and to analyze the potential impact of these factors on schistosomiasis spreading.</p><p><b>METHODS</b>Data of nature and social economy after the construction of the dam in the Three Gorge area were collected, and a cross-sectional study with questionnaire survey on information including social demographic characteristics, people's production and life style, knowledge about schistosomiasis was conducted among natives, emigrations.</p><p><b>RESULTS</b>After the construction of the dam, as the stream became slower, the water-level fluctuating zone on the bank of the reservoir was formed. The main source of drinking water and daily life activity are mainly depends on the river supplying (accounting about 68.7% and 75.8%, respectively); due to the needs of farming, washing cloths and vegetables, 45.6% of resident had a close contact with river water. People with away-from-home employment among emigrations were increased from 5.7% to 18.7%. The proportion of using hygienic lavatory was 88.6%. The main source of water for drinking and daily life among emigrations was tap water (85.4% and 87.0%). The residents had no awareness about the health hazard for schistosomiasis, with less health information</p><p><b>CONCLUSION</b>The natural environment of reservoir areas and the life style are risk factors for the spread of schistosomiasis. The improved sanitation condition and the economy construction after the construction of the dam is propitious to keeping away from the introduction of schistosomiasis. However, people with away-from-home employment among emigrations are still at risk of schistosomiasis.</p>