基于人工智能的传染链路溯源系统的研究

新冠疫情的爆发让全球陷入了巨大的危机之中,如何快速有效地进行传染链路溯源成了疫情防控的重要环节。文章基于既有流行病学调查证据,构建了一套基于图模型框架下的知识推理引擎的传染病传染链路溯源模型,并结合既往疫情模拟仿真推演的相关参数,自动化地还原了疫情在患者间的传播路径,助力溯源工作聚焦重点实现对疫情传播链的追踪和溯源,为疫情防控工作提供决策依据和技术支持。

四川省严重急性呼吸综合征(SARS)传染链阻断措施研究

目的 分析探讨阻断严重急性呼吸综合征 (severeacuterespiratorysyndrome ,SARS)传染链的有效措施 ,研究有效的防治方法。方法 对 17例临床诊断病例 ,6例疑似病例 ,2 0 2例密切接触者采用不同的针对性的规范处置措施 ,并对 14 4名医务人员采取及时的防护措施。结果 17例临床诊断病例中 1例为死亡后确诊 ,16例经医院隔离治疗 ,1例死亡 ,9例治愈出院 ,6例明显好转 ;6例疑似病例经医院隔离治疗 ,5例治愈出院 ,1例明显好转 ;2 0 2例密切接触者经隔离观察后无 1例二代病例发生 ;相关医务人员和区域内所有人员也无 1例二代病例发生。结论 认真而严谨的分析传染链 ,采取切实而可行的措施阻断传染链是防治SARS传播 ,杜绝第二代病例出现的最佳途径。

防御传染病的风景园林应对策略设想--基于打破传染链的视角

近年来新发传染病频现,引起社会广泛关注。风景园林能有效助力公共健康,历史上也曾在应对传染病方面发挥出重要作用,但当前相关研究与实践仍处于起步阶段。以世界卫生组织(WHO)、中国疾病预防控制中心(CDC)和相关重要医学专著、国际期刊为数据来源,从传染病传染链的病原体、传染源、排出门户、传播途径、侵入门户和宿主六大要素出发,分析并总结54种主流传染病暴发的主要环境诱因,包括气候变化、土地利用变化、环境卫生和生态系统4个方面。认为传染病暴发的主要风险在于稳态环境的改变,指出风景园林应对的根本性策略在于通过环境管理手段维持环境的稳态,进而间接作用于传染链要素,实现打破传染链、防控传染病的目的。在此基础上,提出了由防疫评估、变化监测和环境控制构成的风景园林应对传染病策略,并从气候、土地利用、环境卫生、生态系统和配套设施5个方面展开论述。

非典传染链分析及启示

非典是由一个新病原体--冠状病毒传播的,是人类从未发现过的疾病.对它的突然到来,由于认识不足,发生了许多人们意想不到的事,了解历史,了解非典病例传染链及其传播情况,从控制传染病的三个环节进行分析,有助于今后预防和控制非典及其它新传染病.

家校医合力,阻断自伤传染链——初中女生小团体心理危机干预案例

初中生处在身心快速发展时期,同伴是陪伴他们最多的人。原生家庭状况类似的学生常结成小团体,除了相互扶助外,还会传递负性情绪,做出伤害自己和他人的行为。教师发现此类问题时要及时介入,上报学校,并与家长保持密切联系。如果超出学校心理辅导范畴,应当及时转介,同时建议家长向校外专业机构寻求帮助。家校医三方共同努力,帮助学生顺利渡过难关。

深圳3簇严重急性呼吸综合征传染链病例分析

目的 了解深圳 3簇严重急性呼吸综合征 (severeacuterespiraterysyndrome,SARS)的病例特点。 方法 对深圳 3簇SARS病例进行回顾性流行病学调查 ,分析其临床表现及实验检查结果的特点。结果 第 1簇为同事 2人 ,其中深圳首发病例 1周内往返香港 2次 ,于第 2次 (2 0 0 3年 1月 14日 )在香港发病 ;第 2例从香港回深圳后发病。第 2簇一家 5人于广州某医院探病后 1周内先后发病。第 3簇为父子 2人 ,父亲入院前 2周曾往返香港。临床症状均表现高热 ,其中 3例畏寒 ,5例全身肌肉酸痛 ,5例干咳 ,2例咽痛 ,4例头痛 ,2例头晕 ,3例于发病 1周出现气喘伴腹泻并发展成ARDS。 6例在发病 2周内检测冠状病毒相关抗体阳性 ,其中 1例发病后 12 0天的IgG抗体滴度仍为 1:6 4 0。死亡病例的中性粒细胞百分比及中性粒细胞绝对值增高 ,而淋巴细胞百分比及淋巴细胞绝对值降低 ,随着病情加重乳酸脱氢酶明显增高。结论 三簇病例多为异地感染发病 (输入性和散发性 )。在SARS病例中 ,检出冠状病毒相关IgG抗体。

防微杜渐:供应商企业应对核心客户财务风险传染策略研究

财务风险的集聚和传染是引发系统性金融风险的潜藏路径,如何在供应链条上识别和防控财务风险的传染对防范化解系统性金融危机具有重要意义。基于2010—2020年A股上市公司构建的“客户-供应商-年度”样本,深入考察核心客户财务风险对供应商的传染效应以及供应商采取的应对策略。研究结果表明:(1)核心客户的财务风险会传染到其供应商企业,供应商采取公司治理提升策略和信息披露质量改善策略能有效应对风险传染。(2)财务风险传染机制识别发现,利益联动效应和资源联动效应是核心客户财务风险传染到供应商的可能路径。(3)异质性分析发现,当行业环境动态性越高和供应链经营波动性越强时,核心客户财务风险对供应商企业的传染效应越显著,而供应商通过公司治理提升策略和信息质量改善策略对核心客户财务风险传染的应对效果更为显著。

企业金融化存在供应链传染效应吗?

客户是企业收入的主要来源,客户的财务战略对企业投资决策至关重要。利用2009—2021年A股上市公司及其前五名上市客户的金融资产投资数据,分析了客户金融化水平对企业金融资产投资的影响。研究发现,客户金融化水平越高,企业出于“逐利避险”的投资替代动机和预防性储蓄动机持有的金融资产越多。进一步分析发现,投资替代动机是促进企业增加金融资产投资的主要动机,较高的客户金融化水平通过挤出企业实体投资,推动了企业金融化行为。另外,企业金融化供应链传染效应主要由长期金融资产驱动,实体投资回报率低的企业、民营企业对客户金融化水平变动更敏感。从客户驱动视角为企业金融化提供了新的解释,对金融风险防控和引导企业资金“脱虚向实”具有重要的现实意义。

客户风险会影响企业创新投入吗?——供应链传染的视角

创新是提升产业链供应链稳定性和竞争力的重要途径,在供应链传染效应情境下,客户风险是否会影响企业的创新投入?基于2007—2020年沪深A股上市公司的企业-客户关系数据,本文实证检验了客户风险对企业创新投入的影响、作用机制和经济后果。研究结果表明,客户风险与企业创新投入显著正相关,即客户风险越大,企业创新投入越多,并且当企业融资约束越低、客户相对议价能力越强、地区市场化程度越高以及企业高管具有研发背景时,以上正相关关系越显著。机制检验表明,客户风险具有供应链传染效应,会导致企业业绩下滑、经营风险增加,促使企业增加创新投入。经济后果检验表明,创新投入有助于企业增加创新产出、改善市场竞争地位、降低对大客户依赖,有效缓解客户风险带来的负面冲击。本文研究为企业决策层防范客户风险、增强供应链自主可控能力提供了经验证据,同时也为政府职能部门在稳定优化供应链方面提供了新的思路。

客户年报语调具有供应链传染效应吗?——企业现金持有的视角

利用我国供应商企业前五名上市客户及其管理层语调的文本数据,本文考察了跨企业关系情形下客户年报语调对供应商企业现金持有决策的影响。研究结果发现,客户的年报语调越消极,供应商企业则会持有更多的现金,表明客户年报净负面语调在供应链上存在传染效应。进一步的研究发现,非国有性质、相对议价能力较低的供应商企业现金持有与客户年报净负面语调的正相关关系分别显著强于国有性质、相对议价能力较高的供应商企业。此外,当客户融资融券程度较高时,客户年报净负面语调对供应商企业现金持有的正向影响会有所增强。本文的研究不仅在考察跨企业情形下企业现金持有的影响因素以及客户文本信息的经济后果两个方面弥补了国内外现有研究的不足,而且对于企业如何进行现金持有决策提供了一定的经验证据与参考,这对于管理供应链相关风险,推动我国企业的供应链整合进而提升我国企业的全球竞争力具有重要的启示意义。

Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers

AIM: Helicobacter pylori (H pylon) has been linked to chronic gastritis, peptic ulcers, gastric cancer and MALT-lymphoma. Conventional invasive tests are less sensitive than non-invasive tests in diagnosing H pylori infection in patients with bleeding peptic ulcers. Polymerase chain reaction is a sensitive and accurate method for diagnosing H pylori infection. The aim of this study was to evaluate the diagnostic role of mucosai polymerase chain reaction for H pylori infection in patients with bleeding peptic ulcers. METHODS: In patients with bleeding, non-bleeding peptic ulcers and chronic gastritis, we checked rapid urease test, histology, bacterial culture and mucosai polymerase chain reaction fordetecting H pylori infection. Positive H pylori infection was defined as positive culture or both a positive histology and a positive rapid urease test. For mucosai polymerase chain reaction of H pylori, we checked vacA (s1a, s1b, s1c, s2, m1, m1T, m2), iceA1, iceA2. and cag A. RESULTS: Between October 2000 and April 2002,88 patients with bleeding peptic ulcers (males/females: 60/28, gastric ulcers/duodenal ulcers: 55/33), 81 patients with non-bleeding peptic ulcers (males/females: 54/27, gastric ulcers/duodenal ulcers: 45/36) and 37 patients with chronic gastritis (males/ females: 24/13) were enrolled in this study. In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, 45 patients (51%), 71 patients (88%) and 20 patients (54%) respectively were found to have positive H pylori infection (P<0.001). In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, polymerase chain reaction for H pylori infection was positive in 54 patients (61%), 70 patients (86%) and 20 patients (54%) respectively (P<0.001). The sensitivity, positive predictive value and diagnostic accuracy of mucosai polymerase reaction for H pylori infection were significantly lower in patients with bleeding peptic ulcers (84%, 79% and 81%) than in patients with non-bleeding peptic ulcers (99%, 99% and 98%) (P<0.001, P<0.01 and P<0.001 respectively). The sensitivity, negative predictive value and diagnostic accuracy of mucosal polymerase reaction for H py/ori were significantly lower in patients with bleeding peptic ulcers (84%, 83% and 81%) than in patients with chronic gastritis (100%, 100% and 100%) (P= 0.02, P= 0.02 and P=0.001). CONCLUSION: Mucosal polymerase chain reaction for detecting H pylori infection is not reliable in patients with bleeding peptic ulcers.

Impact of environmental and dietary factors on the course of inflammatory bowel disease

Besides their possible effects on the development of inflammatory bowel disease(IBD),some environmental factors can modulate the clinical course of both ulcerative colitis(UC) and Crohn's disease(CD).This review is mainly devoted to describing the current knowledge of the impact of some of these factors on the outcome of IBD,with special emphasis on smoking and diet.Although the impact of smoking on the susceptibility to develop CD and UC is firmly established,its influence on the clinical course of both diseases is still debatable.In CD,active smoking is a risk factor for postoperative recurrence.Beyond this clinical setting,smoking cessation seems to be advantageous in those CD patients who were smokers at disease diagnosis,while smoking resumption may be of benefit in ex-smokers with resistant UC.The role of dietary habits on the development of IBD is far from being well established.Also,food intolerances are very frequent,but usually inconsistent among IBD patients,and therefore no general dietary recommendations can be made in these patients.In general,IBD patients should eat a diet as varied as possible.Regarding the possible therapeutic role of some dietary components in IBD,lessons should be drawn from the investigation of the primary therapeutic effect of enteral nutrition in CD.Low-fat diets seem to be particularly useful.Also,some lipid sources,such as olive oil,medium-chain triglycerides,and perhaps omega-3 fatty acids,might have a therapeutic effect.Fermentable fiber may have a role in preventing relapses in inactive UC.

Biovars and Serotypes of Ureaplasma Urealyticum among Chinese Women Undergoing Routine Gynecologic Exam, Women with Sexually Transmitted Infections, and Female Sex Workers

Objectives: To characterize the distribution pattern of biovars and scrotypes or Ureaplasma urealyyicum in normalhealthy women, sexually transmitted infections clinic clients,and in sex workers. Methods: We cultured cervical swabs taken from 261physical check-up clients, 599 STI clinic outpatients and 98 sexworkers using commercial selective medium. Some positivecultures were further biotyped and serotyped by PCR. Results: (1) U. urealyticum is more commonly isolated in sexworkers (90.8%) than in the physical check-up group (60.9%)or the STI outpatient group (61.3%) (P<0.001). (2) Biovar 1of U. 'realyticum (95.0%), especially single infection ofserotype 1. 3, and 6 of biovar 1, is commonly found in healthywomen. (3) Biovar 2 infection of U urealyticum is moreprevalent in sex workers (28.1%) and STI outpatients group(26.6%) than that in the physical check-up group (4.9%) (P<0.001). (4) Mixed infection caused by more than one serotypeof U urealyticum increased from physical check-up group(8.6%) to STI utpatients (12.4%) to sex workers (23.9%) (P<0.01). (5) There is no statistically significant difference in thedistribution of serotype 1, 3, and 6 of biovar 1 among thesethree groups (P=0.763). (6) The PCR method described here isrelatively simple, rapid and specific for the biotyping andserotyping of biovar 1 of U urealyticum. Conclusion: We should pay more attention to biovar 2 andmixed infections of U. urealyticum than single infection ofhiovar 1 in clinic practice. PCR is a good method for biotypingand serotvping.

First Report of an Outbreak of Contagious Ecthyma in Camels （Camelus dromedarius and Camelus bactrianus） in Iran

Camel contagious ecthyma （CCE） has been reported in Mongolia, Kenya, Somalia and Sudan. CCE is caused by a Parapoxvirus affecting young animals by producing lesions around the lips and nostrils. The generalized form of CCE is uncommon. The aim of this study was to submit the first report of contagious ecthyma in Iran and also to help clinician to diagnose this disease with heavy economic losses easier. In the paper, an outbreak of CCE in dromedary and bactrian camels in Qom province of Iran was described and clinical signs were observed in one camel herd in October 2009. Nodules and scabs from seven affected animals were collected for virus identification. Total extracted DNA was used for polymerase chain reaction （PCR） to amplify a fragment of Parapoxvirus B2L gene. Results showed that camel calves （n = 27） less than one year old and one male bactrian camel were affected （no adult female camels were found to be infected）. The prevalence of the disease in the herd, adult camels and camel calves was 30.33%, 1.5% and 100%, respectively. Affected animals showed the swelling of head with nodular lesion around the lips. It then developed to pustules and fissured crusts. Previous involvement with this disease, history of contact with sheep or goats, food resources and season all can have a role in epidemiology of the disease.

Investigation on Infectious Agents of Aborted Pig Fetuses and Its Correlation with PRRSV MLV Vaccine

Infectious agents causing aborted fetus problems in domestic pigs were investigated in this study. More than 10 different infectious agents were known to cause abortion in swine and the major eight viruses among them were inspected. One hundred twelve samples of aborted fetuses from nine provinces in South Korea were collected during April to November, 2013 in this study for the diagnosis of infectious agents causing abortions in pigs. Eight major infection viruses were examined in this study mainly using various diagnostic kits and reverse transcriptase polymerase chain reaction （RT-PCR）. Positive rate of the detection differed from each viruses. In this study, the main focus was the porcine reproductive and respiratory syndrome virus （PRRSV）, which took the second large portion in the positive rate of detection, and then its ORF5 gene was compared with modified live virus （MLV） vaccine strain to figure out the influence of vaccine on disease. Between four positive samples＇ sequence, two of them were 99.9%-100% similar to MLV vaccine strain and two other samples were 88.6%-92.7% similar. Similarity rate of the sequences between the vaccine and virus from aborted fetuses are very crucial, because it implies that abortion in swine can be made due to the usage of vaccine not only by the infection of field virus, and if MLV vaccine actually do have an impact on the infection, usage of the vaccine should be reconsidered.

新冠肺炎疫情期间要少吃生鲜食品

前段日子,新冠病毒再次肆虐北京新发地市场,而且出现在三文鱼的案板上,尽管传染链尚未查清,可有一点是明确的,就是新冠病毒非常喜欢阴冷潮湿的环境。

隔离病源 提高效率——思科倡导发挥网络在抗击SARS中的特殊作用

自SARS爆发以来至5月中旬，医务人员感染SARS的比例接近患病总人数的20%，医务人员感染SARS不仅关系到广大医务人员的身体健康和安全保障问题，也是切断SARS传染链，全面取得抗击SARS胜利的关键。为此，各医疗单位采取了许多有效措施以千方百计降低医务人员的感染率。

北京医护人员SARS高感染率真相

一条传染链 3月5日上午,全军最著名的传染病医院——302医院,突然接到兄弟医院301医院的紧急电话,称此前一天来该院急诊室观察的山西3名患者病情“怪异”,怀疑是“非典型肺炎”,需要转到302医院医治。 当天下午16时30分左右,3名患者转运到302医院,两名用平车推着,1名被搀扶着,没有采取任何防护措施。

Evaluation of Epstein-Barr Virus Salivary Shedding in HIV/AIDS Patients and HAART Use: A Retrospective Cohort Study

Little data is available on the evaluation of the occurrence rates of Epstein-Barr virus(EBV) in saliva and relationship with highly active antiretroviral therapy(HAART) use in HIV/AIDS patients in China. We conducted a retrospective cohort study of EBV serological tests for HIV/AIDS patients who were treated in the hospitals for infectious diseases in Wuxi and Shanghai, China from May 2016 to April 2017. The EBV-seropositive samples were identified by ELISA. EBV-specific primers and probes were used for the quantitative detection of viral DNA from saliva via quantitative real-time polymerase chain reaction. CD4 cell counts of the HIV/AIDS patients were detected by a flow cytometry. A total of 372 HIV/AIDS patients were ultimately selected and categorized for this retrospective cohort study. For EBV IgG and IgM, the HIV/AIDS HAART use(H) and non-HAART use(NH) groups had significantly higher seropositive rates than the HIV-negative control group. The HIV/AIDS(NH) group had the highest seropositive rate(IgG, 94.27%; IgM, 68.98%) and the highest incidence of EBV reactivation or infection. For salivary EBV DNA-positive rates and quantities, the HIV/AIDS(H)(73.69%) and the HIV/AIDS(NH)(100%) groups showed significantly higher values than the HIV-negative control group(35.79%,[ twofold). Further, the salivary EBV DNA-negative population had significantly higher CD4 cell counts than the EBV DNA-positive population in the HIV/AIDS(H) group and the HIV/AIDS(NH) groups. Thus, HAART use is beneficial in decreasing the EBV salivary shedding in HIV/AIDS patients and indirectly decreases EBV transmission risk.