[Analysis on the frequency of urinary iodine in a population-based intervention study].

OBJECTIVE: Through a two-year follow up program, this study was to analyze the urinary iodine frequency of a cohort in the intervention trial, concerning different doses of salt ionization, so as to explore the selection of appropriate concentration of salt ionization. METHODS: A multistage cluster sampling method was used to select three townships in two countries for community intervention with different doses [(15±5) mg/kg, (25±5) mg/kg, (35±5) mg/kg] of salt ionization. RESULTS: After intervention, the median of urinary iodine was reduced among the population. The urinary iodine frequencies of (15±5) mg/kg and (25±5) mg/kg among groups of children were mainly concentrated in 100-200 µg/L and 200-300 µg/L paragraphs in A county. While the 300 µg/L paragraph had an overall decline in B county, the 100 µg/L and 200 µg/L paragraph ratio increased but the trend seemed to be slow. The 100-300 µg/L paragraph of the four treatment groups took a larger proportion and kept smooth in a more ideal state. However, the control group still maintained at above 250 µg/L level. CONCLUSION: The iodine supplementation should be gradually implemented in Chongqing. The doses of salt ionization should be reduced from the current (35±15) mg/kg to (25±5) mg/kg in the economically developed areas. At the same time, we need to continuously follow the changes of the condition.

[Prevalence of Enterobius vermicularis infection of children and its influencing factors in Chongqing City].

OBJECTIVE: To understand the infection status of Enterobius vermicularis of children aged 3-12 years and its influencing factors in Chongqing City. METHODS: One rural county and 1 urban county were selected as investigation areas. The children aged 3-12 years of 5 towns from 5 different directions of each county were investigated. About 150 children were investigated every town. The Enterobius vermicularis eggs of children were detected by the adhesive cellophane anal swab method. The children's parent education levels and personal circumstances of sanitation were investigated by the questionnaire survey. RESULTS: Among 1 592 children investigated, the total infection rate of Enterobius vermicularis was 6.85%. The infection rates of boys and girls were 6.29% and 7.40%, respectively. The infection rates of rural and urban areas were 12.13% and 2.14%, respectively. The infection rate in children aged 5-7 years was the highest (13.56%) among all the child aged groups. There were significant differences for the infection rates of Enterobius vermicularis among children of different aged groups, different areas, different education levels and occupations of parents, washing hand before meal or not, washing hand after WC or not, different classroom grounds, and lodging or not (P < 0.01 or P < 0.05). The multivariate logistic analysis indicated that aged group, different areas, classroom ground and lodging children were independent risk factors for Enterobius vermicularis infection. CONCLUSIONS: The infection rate of Enterobius vermicularis in rural area is higher than that in urban area. The control emphases should be the children of low group, rural area, poor classroom and lodging.

[Influence factors of Enterobius vermicularis infection among pupils in Chongqing City].

OBJECTIVE: To investigate Enterobius vermicularis infection among primary school students and its influence factors in Chongqing. METHODS: Beibei and Changshou were selected as investigated points from October to December 2011. One primary school was randomly chosen from each of the 5 different directions in every investigated point. Adhesive cellophane anal swab was used to examine pinworm eggs for 3 consecutive days. Information on children's family, hygiene habits and school environment was collected by questionnaire. RESULTS: The total infection rate of E. vermicularis was 6.7% (71/1 071). The infection rate in rural schools (7.9%, 60/755) was higher than that of urban schools (3.8%, 12/316) (chi2 = 6.1169, P < 0.05). The rate in males and females was 6.3% (34/536) and 7.1% (38/535), respectively (chi2 = 0.2463, P > 0.05). Among the investigated children aged 6-12 years, the infection rate in 6-year-old children (16.03%) was highest. There was a statistical significance among age groups (chi2 = 29.1492, P < 0.01). With the increase of age, the rate decreased. Multivariate logistic regression analysis showed that location (OR = 0.411), age groups (OR = 0.714), education level of mothers (OR = 0.568), materials of classroom-ground (OR = 0.116) and types of boarding (OR = 0.272) were the influence factors on E. vermicularis infection in primary schools (P < 0.05). CONCLUSIONS: Pinworm control should more focused on rural children, younger group, mothers with lower education, classroom with cement ground and lodging schools in Chongqing City.

[Construction and expression of recombinant plasmid pET28alpha-Sj26GST of Schistosoma japonicum in Escherichia coli BL21].

OBJECTIVE: To construct and express recombinant plasmid pET28a-Sj26GST of Schistosoma japonicum (Sj) in Escherichia coli BL21 (DE3). METHODS: The total RNA was extracted from Sj adult worms by ultrasound-breaking. The Sj26GST antigen gene was amplified by RT-PCR from the total RNA, and then cloned into prokaryotic expression plasmid pET28alpha and transformed into E. coli BL2 (DE3). The BL21(pET28a-Sj26GST) was induced with isopropyl-beta-D-thiogalactopyranosid (IPTG), and the expressed products were analyzed and identified with SDS-PAGE and Western blot. RESULTS: The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET28alpha. The recombinant plasmid pET28a-Sj26GST was successfully constructed, with a relative molecular weight of expressed recombinant protein at approximately 36 x 10(3) as determined by SDS-PAGE. The amount of the expressed protein comprised 26% of the total bacterial proteins. The fusion protein could be recognized by the sera of rabbits infected with Sj. CONCLUSION: The recombinant plasmid pET28alpha-Sj26GST is successfully constructed and highly expressed in E. coli in a fused form with His-tag. The expressed fusion protein shows specific antigenicity.