空间统计学在食品污染物分布研究中的应用

目的 以2017年某省食品安全监测大米中砷含量数据为例，探讨空间统计学方法在食品污染物分析中的应用价值。方法 采用空间点模式估计、核密度分析，全局以及局部自相关性分析等空间统计学方法，在县级空间尺度下，对某省大米中砷含量进行探索性空间数据分析。结果 空间点模式分布图显示，该省大米砷污染的空间分布比较分散，核密度分析结果显示污染热点区域主要在该省中东部地区。全局自相关Moran''s I指数值为0.11，有统计学意义，大米样品中砷污染呈现出低度空间聚集性。有1个"高-高"聚集区，2个典型的"低-低"聚集区。结论 空间统计学运用于食物污染物分布研究上，可以很好地可视化展示、识别污染分布规律、热点地区和聚集区，为基于问题的监测工作的开展提供技术支持。     

Evaluation of immune responses in dogs to oral rabies vaccine under field conditions

During the 20th century parenteral vaccination of dogs at central-point locations was the foundation of successful canine rabies elimination programs in numerous countries. However, countries that remain enzootic for canine rabies have lower infrastructural development compared to countries that have achieved elimination, which may make traditional vaccination methods less successful. Alternative vaccination methods for dogs must be considered, such as oral rabies vaccine (ORV). In 2016, a traditional mass dog vaccination campaign in Haiti was supplemented with ORV to improve vaccination coverage and to evaluate the use of ORV in dogs. Blisters containing live-attenuated, vaccine strain SPBNGAS-GAS were placed in intestine bait and distributed to dogs by hand. Serum was collected from 107 dogs, aged 3–12 months with no reported prior rabies vaccination, pre-vaccination and from 78/107 dogs (72.9%) 17 days post-vaccination. The rapid florescent focus inhibition test (RFFIT) was used to detect neutralizing antibodies and an ELISA to detect rabies binding antibodies. Post-vaccination, 38/41 (92.7%) dogs that received parenteral vaccine had detectable antibody (RFFIT >0.05 IU/mL), compared to 16/27 (59.3%, p < 0.01) dogs that received ORV or 21/27 (77.8%) as measured by ELISA (>40% blocking, p < 0.05). The fate of 291 oral vaccines was recorded; 283 dogs (97.2%) consumed the bait; 272 dogs (93.4%) were observed to puncture the blister, and only 14 blisters (4.8%) could not be retrieved by vaccinators and were potentially left in the environment. Pre-vaccination antibodies (RFFIT >0.05 IU/mL) were detected in 10/107 reportedly vaccine-naïve dogs (9.3%). Parenteral vaccination remains the most reliable method for ensuring adequate immune response in dogs, however ORV represents a viable strategy to supplement existing parental vaccination campaigns in hard-to-reach dog populations. The hand-out model reduces the risk of unintended contact with ORV through minimizing vaccine blisters left in the community.     

When does the sex ratio of offspring of the paternal 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure decrease: In the spermatozoa stage or at fertilization?

Recent animal experiments confirmed that paternal 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure decreases the sex ratio of offspring at birth without altering litter size. However, the timing of this decrease remained unclear. Male mice were administered TCDD at 7–12 weeks of age and mated with non-treated females. The Y-bearing/X-bearing sperm ratio was examined by real-time PCR and FISH methods, and the sex ratio of the 2-cell embryos collected from non-treated females that had been mated with TCDD-exposed males were investigated by nested PCR. The Y-bearing/X-bearing sperm ratio was not significantly decreased in the TCDD group. However, the sex ratio of the 2-cell embryos of the TCDD group was significantly lower than that of the control group. These results may have resulted from a decrease in fertility of Y-bearing sperm. Thus, the results of this study suggested that the sex ratio of the offspring was decreased at fertilization and not during the spermatozoa stage.     

Perinatal events and neonatal morbidity: An analysis of 5380 cases

The associations between perinatal events and neonatal morbidity were examined in a regional population of 5 380 newborns weighing 500 g or more. Perinatal mortality was 6.9%0, and neonatal mortality was 3.0%0. The low birth weight (< 2500 g) rate was 3.8%. The incidence of prematurity (gestational age < 37 weeks) was 6.6%. Respiratory distress syndrome was found in 0.9%, nonhaemolytic hyperbilirubinaemia in 16.5%, hypoglycaemia in 0.5%, septic infection in 0.8%, asphyxia in 4.0%, intracerebral haemorrhage in 0.3%, and cerebral symptoms in 0.7%. Maternal toxaemia, multiple pregnancy and maternal short stature were associated with spontaneous prematurity and a birthweight below the 10th percentile. Prematurity was associated with respiratory distress syndrome, hyperbilirubinaemia, hypoglycaemia, infection, low Apgar scores, asphyxia and intracerebral haemorrhage. Placental complications were associated with spontaneous prematurity, low Apgar scores and asphyxia. Premature rupture of the membranes was associated with spontaneous prematurity, infection, low Apgar scores and asphyxia.     

白银市2013—2021年农村义务教育学校食品微生物污染状况

  目的  分析白银市农村义务教育学校食品中微生物污染水平和趋势,为对消除食品安全隐患起到预警作用提供参考。  方法  按照随机抽样原则,在白银市两区三县分别选取2~6所农村义务教育学校,依据《国家食品污染物和有害因素风险监测工作手册》等进行沙门菌、单核细胞增生李斯特菌、金黄色葡萄球菌等8种致病菌及细菌总数、大肠菌群2种卫生学指示菌检测。  结果  2013—2021年共采集各类食品908份,阳性47份,总体阳性率为5.18%,不同年份采集样品阳性率呈逐年下降趋势(χ_趋势2=23.09,P < 0.05)。检出致病菌由高至低依次为大肠埃菌(1.87%)、蜡样芽胞杆菌(0.99%)、金黄色葡萄球菌(0.44%)、霉菌(0.33%)、单核细胞增生李斯特菌(0.22%)。卫生学指示菌指标细菌总数超标率较高(2.09%)。各类食品中,奶及奶制品、冷冻食品、凉拌食品、烧烤、米面制品等阳性率较高。按季度统计,第一、二季度阳性率较高。  结论  农村义务教育学校食品中存在不同程度的微生物污染风险,应关注贫困地区学校食品卫生安全的现状,加强农村义务教育学校食品,特别是对奶及奶制品、冷冻食品、凉拌食品、烧烤、米面制品等重点食品的监管。     

The effect of bacille Calmette-Guérin vaccination at birth on immune response in China

Bacille Calmette-Guérin (BCG) vaccine is still the most effective approach to prevent tuberculosis in childhood. In order to provide protection against severe forms of childhood tuberculosis, it is customary to give BCG vaccination at birth in China. Tuberculin skin testing after vaccination is usually used to evaluate the immunogenic activity and protective efficacy of the BCG. We report the results of a multi-site prospective cohort study to evaluate the immunological reactivity against BCG in four prefectural cities in China. A total of 59,022 newborn infants were vaccinated between January 2011 and March 2012, and follow-up data on 27,517 vaccinated infants were available for this study. Of these, 679 (2.5%) had PPD readings of 0–5 mm, 17,072 (62.0%) had PPD readings of 5–10 mm of induration, 8864 (32.2%) had readings of 10–15 mm, 815 (3.0%) had readings of 15–20 mm, and 87 (0.3%) had readings of >20 mm of induration. The size of PPD reaction varied significantly with the geographic location, gender, season of vaccination, and grade of hospital administering the BCG vaccine (P < 0.001). 97.8% of the infants with a BCG scar of >1 mm had a positive TST reaction. However, only 56.9% of infants without a BCG scar had a positive PPD reaction. Our results demonstrate that the BCG immunization among newborn infants in China induces satisfactory immune response. In addition, BCG scars provide a useful indicator of vaccination response in Chinese infants.