ABSTRACT
Objective To explore the distribution of prevalence rates of typhoid and paratyphoid,with drug resistance and molecular types ofSalmonella(S.) typhi and S.paratyphi in Jiangsu province.Methods Data,collected by the national infectious disease reporting system in Jiangsu province from 2007 to 2011,was analyzed.K-B method was used to test the sensibility to 9 kinds of antibiotics among 210 stains of S.typhi and S.paratyphi.81 strains of S.typhi were classified by pulse-field gel electrophoresis (PFGE).Results The annual average incidence of typhoid and paratyphoid was 0.47 per 100 000 in the last five years,showing a decreasing trend.Highest incidence (1.70 per 100 000)was seen in the ＜ 1 year age group,with S.typhi and S.paratyphi A accounted for 66.19％ and 23.81％ among the 210 stains.The rate of drug resistance to nalidixic acid appeared to be the highest as 66.19％.The drug resistant rates to 6 kinds of antibiotics were on average,lower than 10.00％.The multi-drug resistant rate of S.typhi and S.paratyphi was 30.00％.In the last 3 years,37 types from 81 S.typhi strains had been classified into 4 clusters by PFGE.The predominant type was JPPX01.JS0027,accounted for 11.11％.JPPX01.JS0001 type had a specific regional distribution,but JPPX01.JS0014,JPPX01.JS0018 and JPPX01.JS0024 strains were widely spread.Results from the clustering analysis showed that cases in the 3 events tended to have a clustering nature.Conclusion The morbidity of typhoid and paratyphoid was in a relatively low level in Jiangsu province.Although S.typhi and S.paratyphi were sensitive to most of the commonly used antibiotics,the resistance rates to some kinds of antibiotics were increasing.The distribution of typhoid was sporadic in Jiangsu and without the dominant strain,it was unlikely that typhoid could become epidemic in the future,in Jiangsu.
ABSTRACT
<p><b>OBJECTIVE</b>By using Benchmark Dose (BMD) approach to explore the relations among drinking water fluoride, urine fluoride, serum fluoride and dental fluorosis; and to evaluate the significance of urine fluoride and serum fluoride in control and prevention of endemic fluorosis.</p><p><b>METHODS</b>512 children (290 in Xinhuai Village, 222 in Wamiao Village) aged 8-13 years were recruited in the study. Epidemiological methods were used to investigate the prevalence of dental fluorosis, and the levels of urine fluoride, serum fluoride, and drinking water fluoride in superficial well. The children were divided into six subgroups by the concentration of fluoride in drinking water: < 0.5 mg/L, 0.5-mg/L, 1.0-mg/L, 2.0-mg/L, 3.0-mg/L and > or = 4.0 mg/L.</p><p><b>RESULTS</b>There was significant dose-response relationship between the drinking water fluoride and the prevalence of dental fluorosis or the prevalence of defect dental fluorosis. The BMDLs (Benchmark Dose Lower Bound) were 1.01 and 1.30 mg/L, respectively. Urine fluoride and serum fluoride also had significant dose-response relationship to the prevalence of dental fluorosis or defect dental fluorosis. The correlation coefficient between drinking water fluoride and urine fluoride was 0.717, and it was 0.855 between drinking water fluoride and serum fluoride, and 0.617 between urine fluoride and serum fluoride.</p><p><b>CONCLUSIONS</b>The currently national standard of fluoride in drinking water in China is safe and reasonable. As a biological monitoring index, the levels of fluoride in serum may be more useful than that in urine in the control and prevention of endemic fluorosis.</p>