Evaluation of a method for issuing warnings pre-epidemics and epidemics in Japan by infectious diseases surveillance

BACKGROUND: Simple methods have been developed to warn of pre-epidemics and epidemics in small areas using data of infectious diseases surveillance. Epidemic warnings are made if the index of cases per week per sentinel medical institution is greater than a defined value. A pre-epidemic warning means that an epidemic warning will be given in the following four weeks. While the methods are used routinely for surveillance in Japan, they remain to be validated. METHODS: Infectious diseases surveillance data of influenza-like illness and 12 pediatric diseases in the fiscal year between 1999 and 2001 were used in the analysis. We examined the frequency of warnings, temporal changes in the index before and after the onset of a warning, and the sensitivity, specificity, and positive predictive value of pre-epidemic warnings. RESULTS: For the majority of the diseases investigated, the proportion of weeks in which a warning was issued ranged between 0% and 10%. In several diseases including influenza-like illness, we observed a rapid increase and gradual decrease in the index before and after a warning. The sensitivity, specificity, and positive predictive value of a pre-epidemic warning were 90.4%, 93.7% and 23.9% for influenza-like illness, and ranged between 25.1-54.2%, 86.1-99.2%, and 2.5-20.8% for the pediatric diseases (chickenpox, rubella, measles, and mumps), respectively. CONCLUSIONS: The study showed that the methods used for determining whether or not to issue an epidemic warning were satisfactory in some diseases, including influenza-like illness, and may need to be improved in several other diseases.     

Detection of epidemics in their early stage through infectious disease surveillance

BACKGROUND: Surveillance of infectious diseases is done in many countries. The aims of such surveillance include the detection of epidemics. In the present study, the possibility of detecting an epidemic in its early stage using a simple method was evaluated for 16 infectious diseases. METHODS: We used as an index the number of cases per week per sentinel medical institution in the area covered by a health centre in infectious disease surveillance in Japan in 1993-1997. Periods of epidemics in health centre areas were determined according to the reported indices. The simple method used for detecting the early stage of an epidemic is that if the index exceeds a critical value, then an epidemic will begin in the following 4 weeks. The sensitivity, specificity and positive predictive value for this epidemic warning were evaluated for given critical values. RESULTS: When the specificity of the epidemic warning was more than 95%, the sensitivity was more than 60% in ten diseases, and more than 80% in four diseases (influenza-like illness, rubella, hand-foot-and-mouth disease, and herpangina). The positive predictive value was between 15.6% and 31.4% in these ten diseases. CONCLUSION: The early stage of epidemics of some infectious diseases might be detectable using this simple method.     

Estimate of underreporting of infectious diseases through a sentinel network of pediatricinas in the area of local health unit of Florence

The aim of this study was to evaluate the underreporting of some infectious diseases in the pediatric population in the Local Health Unit of Florence in the period 15.09.1997-14.09.1998. Data from the current notification system and from an a hoc sentinel network were used. Nine family pediatricians voluntarily participated in the sentinel network, notifying all cases of measles, mumps, pertussis, rubella, scarlet fever and chickenpox diagnosed in the population of children under their professional responsibility, in the period of the study. Chickenpox was the most frequent disease (2,043 cases equal to 73.5% of total notifications). The notification rate for chickenpox obtained with the sentinel network was 41.6 per 1,000 children, meanwhile the notification rate obtained with the current notification system was 23.7 per 1,000. The notification rate for scarlet fever was 24.1 per 1,000 with the sentinel network and 6.0 per 1000 with the current notification system. The underreporting for the two diseases was respectively 43% and 75%. Voluntary participation of physicians in sentinel network guarantees data of good quality, making these networks very useful tools for the epidemiologic evaluation of infectious diseases with benign prognosis.     

Utility of System Generated Syndromic Surveillance Alerts to Detect Reportable Disease Outbreaks

Objective

In light of recent outbreaks of pertussis, the ability of Florida Department of Health’s (FDOH) Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE-FL) to detect emergent disease outbreaks was examined. Through a partnership with the Johns Hopkins University Applied Physics Laboratory (JHU/APL), FDOH developed a syndromic surveillance system, ESSENCE-FL, with the capacity to monitor reportable disease case data from Merlin, the FDOH Bureau of Epidemiology’s secure webbased reporting and epidemiologic analysis system for reportable diseases. The purpose of this evaluation is to determine the utility and application of ESSENCE-FL system generated disease warnings and alerts originally designed for use with emergency department chief complaint data to reportable disease data to assist in timely detection of outbreaks in promotion of appropriate response and control measures.

Introduction

Reportable disease case data are entered into Merlin by all 67 county health departments in Florida and assigned confirmed, probable, or suspect case status. De-identified reportable disease data from Merlin are sent to ESSENCE-FL once an hour for further analysis and visualization using tools in the surveillance system. These data are available for ad hoc queries, allowing users to monitor disease trends, observe unusual changes in disease activity, and to provide timely situational awareness of emerging events. Based on system algorithms, reportable disease case weekly tallies are assigned an awareness status of increasing intensity from normal to an alert category. These statuses are constantly scrutinized by county and state level epidemiologists to guide disease control efforts in a timely manner, but may not signify definitive actionable information.

Methods

Within the ESSENCE-FL query portal, the Merlin Reportable Diseases Data Source was selected with a weekly time resolution by event date. Case Classification included all confirmed, probable and suspect cases, reported and not yet reported, during the time period of week 35, 2011, to week 35, 2012. The ESSENCE Weighted Moving Average (EWMA 1.2) detector was used to classify weekly counts as either of normal, warning or alert status based on previous weeks’ counts, indicating the possibility of an emerging outbreak. These weekly statuses were then compared with outbreaks reported in Merlin’s fully integrated outbreak reporting system and with outbreak reports submitted to EpiCom, Florida’s EpiX or health alert network. An ESSENCE-FL generated warning or alert was considered valid if a corresponding outbreak of 2 or more epi-linked pertussis cases were reported in either Merlin’s outbreak module or in EpiCom. For the sake of brevity in this abstract, the analysis of pertussis is presented, while other reportable disease conditions of immediate interest will be presented at the conference.

Results

Examination of 494 pertussis cases reported from September 2011 to September 2012 showed that of 53 weeks, 38 weeks contained normal case counts, 11 weeks generated warnings, and 4 weeks produced alerts. The number of warnings that corresponded to actual outbreaks was 6 of 11, whereas 2 of the 4 alerts matched reported outbreaks. Of the remaining 38 weeks, 12 had outbreaks reported with no warning or alert generated by ESSENCE-FL. When comparing confirmed outbreak status with ESSENCE-FL weekly data count status, warning/alert versus normal, it was found that the sensitivity of ESSENCE-FL to detect a true outbreak was 40.0% while the specificity was 78.8%. This comparison generated a positive-predictive value of 53.3% and a negative predictive value of 68.4%.

Conclusions

The ability of ESSENCE-FL to act as a first alert system for emerging disease events using Merlin reportable disease data should be considered with constraint. While warnings or alerts about potential pertussis outbreaks were generated correctly about half the time, the nearly one-third of reported outbreaks with no warning or alert makes the utility of the alerts questionable as far as initiating immediate action without prior verification of the alert. Florida does not currently have a requirement for centrally documenting all outbreaks, so it is likely that outbreaks occurred but were not recorded, precluding verification of all outbreaks.     

学校传染病症状监测及暴发疫情分析

目的对学校传染病症状监测系统进行评价,对疫情暴发情况进行分析。方法天津市滨海新区汉沽疾控中心于2012年9月起在辖区34年学校中选取7所监测点学校,开展学生因病缺课传染病症状监测工作。并与监测点医院数据进行比对,对症状监测系统进行效果评价。结果 2012年9月3日—2013年1日15日(1个学期),监测点学校症状监测系统共报告缺课学生人数540例,符合流感样病例人数255例,占47.22%,普通感冒244例,腹痛、腹泻13例,肺炎11例。7所学校及时发现5所学校流感暴发事件,均为甲3型季节流感。其中2所中学,3所小学。5所学校累计报告流感样病例170例,波及人数506例,平均罹患率为3.09%。哨点医院监测发现学校流感样病例暴发疫情较学校监测时间晚了17 d。结论通过对学校症状监测,可对传染病疫情及时预警,补充哨点医院监测系统中的不足,及时发现暴发疫情,及时处置。     

腹泻症状监测与法定报告肠道传染病监测的错位相关分析

目的分析2007-2009年成都市腹泻症状监测数据和同期法定报告传染病中的肠道传染病监测数据的时间变化及相互关系,找出两者之间的变化规律,为肠道传染病预警提供更有效的方法。方法采用错位相关分析两数据源的时间错位相关关系,定量研究两数据源的时间先导性。结果法定报告肠道传染病发病率与腹泻症状患者报告率在3年监测同一时刻均具有相关关系,经过错位相关分析得到,2007年、2008年腹泻症状患者报告率和前移1周的肠道传染病发病率的相关系数最大,滞后时间在1周左右。对于其他感染性腹泻,腹泻症状监测报告率分别与2007年、2008年前移1周的其他感染性腹泻发病率的相关性最高,而对于菌痢,3年均表现为监测本周的两数据源时间分布最为相近。结论腹泻症状监测可以提前1周左右提示法定报告肠道传染病的发生,尤其对其他感染性腹泻和菌痢的预警作用比较明显,对该监测数据的预警分析能在一定程度上起到早期发现肠道传染病流行趋势的作用。     

Temporal and geographical variation in epidemics determined from the results of an infectious disease surveillance system in Japan description of epidemic patterns by data-based criteria for epidemic periods

OBJECTIVE: After developing criteria for epidemic periods for 16 infectious diseases, we investigated temporal (annual and monthly) and geographical (regional) variation in epidemics. METHODS: Data from an infectious disease surveillance system for the years 1993 to 1997 were used for the analysis. The weekly number of patients per monitoring station was calculated from the data and used in developing criteria for an epidemic period. Based on these latter, we calculated the average number of epidemics occurring at each public health center in a year, an average length of the epidemic period, and the average number of patients per monitoring station reported during an epidemic period. These figures were used to explore temporal (annual, monthly) and geographical (regional) variation. RESULTS: With most diseases, the average number of epidemics occurring at a public health center was 0.3-0.5 per year and the average length of an epidemic period was 6-12 weeks. The average number of patients per monitoring station reported during an epidemic period differed according to the diseases. These indices showed that there were few annual differences, but great monthly differences, in most diseases. The average number of epidemics occurring in a public health center showed regional differences with some diseases. CONCLUSION: Temporal and geographical variation in epidemics for 16 infectious diseases was established by developing criteria for an epidemic period.     

沈阳市流行性感冒监测数据的早期预警效果

目的利用现有的流行性感冒(流感)监测数据,探讨流感早期预警指标及其在2009年甲型流感大流行中的预警效果。方法选用沈阳18所哨点医院门诊流感样病例既往监测数据,采用控制图法,建立预警线,对2009和2010年的流感样病例百分比(ILI%)数据进行拟合,并结合新甲型H1N1疫情和病原学监测结果综合分析其早期预警效果。结果控制图法显示,ILI%较病原学监测和大疫情数据提前1周超过警戒线,ILI%趋势于新甲型H1N1疫情、流感病毒检出率变化趋势基本一致。结论 ILI%作为流感活动的监测指标较为可靠,控制图法可作为流感大流行敏感有效的早期预警指标。     

疫苗可免疫预防传染病的季节分布

目的通过探讨疫苗可免疫预防传染病的季节分布,为监测和防制提供科学依据。方法采用集中度及圆形分布法分析。结果流行性乙型脑发病有严格的季节性,流行性脑脊髓膜炎发病有很强的季节性,麻疹和风疹发病季节性明显,百日咳发病有一定的季节性;流行性感冒、流行性腮腺炎和水痘全年发病水平相当。结论可以针对不同传染病发病时间,采取相应的措施,达到预防和控制的目的。     

西湖区传染病监测自动预警信息系统应用

目的通过对2008-2009年传染病自动预警信息系统数据的分析,了解并正确评价该预警系统。方法利用Excel软件系统对2008年4月21日—2009年4月20日南昌市西湖区重点传染病监测自动预警信息系统异常报告资料与月统计报表、中国疾病监测信息报告管理系统报告的相关重点传染病发病例数等数据进行分析。结果通过分析可知,对区重点疾病进行预警,2008年4-12月预警次数前三位是其他感染性腹泻、流行性腮腺炎、痢疾,2009年1-4月预警次数前三位是其他感染性腹泻、麻疹、痢疾;自2009年1月预警系统改进后,对重复预警有了很好的筛查,预警重复率从2008年的42.5%下降至2009年的36.8%;2008年重点疾病中当前值和实际情况符合率均达到80%,2009年情况符合率更达到90%;结论传染病预警是一项长期性工作,结合地区实际情况、充分利用国家传染病自动预警信息系统,做到传染病疫情的早期发现核实,及时调查处理,使传染病暴发得到较早控制,人员、经济的损失降到最低。     

Congenital rubella syndrome (CRS) in Vietnam 2011–2012—CRS epidemic after rubella epidemic in 2010–2011

BackgroundRubella is endemic in Vietnam with epidemics occurring every 4–5 years. In 2011, Vietnam experienced the large nationwide rubella epidemic. During the rubella epidemic, many infants born with congenital rubella syndrome (CRS) were identified and reported from the neonatal units or cardiology departments of the national hospitals. To understand the burden of CRS, National Expanded Program on Immunization (NEPI) established sentinel CRS surveillance system.MethodThree national paediatric hospitals in Hanoi and Ho Chi Minh City (HCMC) were selected as CRS sentinel surveillance sites. Blood specimens from the infants were collected for rubella specific IgM and ELISA testing was performed at the national measles and rubella laboratory.ResultsFrom January 2011 to December 2012, 424 infants with suspected CRS were identified and reported. Among them 406 (96%) had specimens obtained, 284 (70%) cases were IgM positive including 279 laboratory confirmed CRS and 5 Congenital Rubella Infection (CRI). 13 cases were clinically confirmed and 127 (30%) were discarded. Total 292 infants were confirmed as CRS. Of the 292 infants with CRS, 69% of mothers had a history of “fever and rash” during pregnancy, of which 85% was in the first trimester. The most common clinical defects were congenital heart disease and cataract(s). However, 81.9% of the infants had a combination of major and minor signs and symptoms. Low birth weight in full term infants with confirmed CRS was observed in 114 infants (39%).ConclusionsThe newly established CRS sentinel surveillance system documented the significant burden of CRS in Vietnam and provided evidence to the policy makers for the introduction of rubella containing vaccine (RCV) into Vietnam. This report highlights the importance of countries with rubella epidemic to establish CRS surveillance rapidly in order to support the introduction of RCV into the routine Expanded Programme on Immunization (EPI) immunization.     

加强新发传染病哨点监测工作构筑重大疫情第一道防线

点监测是传染病早期发现的有效手段和技术,加强新发传染病哨点监测工作,构筑重大疫情第一道防线,对于及时发现病人、缩短传播窗口期和提高新发传染病防控效果至关重要。本文拟分析新发传染病哨点监测的作用和意义,总结新型冠状病毒疫情中哨点监测工作存在的不足,提出加强新发传染病哨点监测的具体措施与建议,以期为更强有力地开展疫情防控工作提供参考,也为建立新发传染病哨点监测长效机制提供依据。     

Comparison of sentinel surveillance of influenza like infections in Martinique and in Guadeloupe during influenza A(H1N) 2009 pandemic: use of a phone survey and hospital surveillance

BackgroundSentinel general practitioner networks monitor influenza-like infections (ILI) in Martinique and in Guadeloupe (French West Indies). During the A(H1N1)2009 pandemic, they gave an ILI incidence estimation higher in Martinique than in Guadeloupe. In October 2009, a telephonic survey was launched in both islands to assess the number of ILI diagnoses performed by general practitioners since the beginning of the pandemic. This paper compares the results of sentinel surveillance, of telephonic survey and of hospital surveillance in Guadeloupe and in Martinique.MethodsOn each island, the sentinel network gathers a representative sample of voluntary general practitioners. Each week, they report the number of ILI they diagnosed the past week. Times series of these weekly numbers were modelized using the Serfling method with the upper limit of the confidence interval of the expected value representing the epidemic threshold. The telephone survey was conducted from October 2, 2009 to October 12, 2009 in Martinique and from October 13, 2009 to October 21, 2009 in Guadeloupe. The quota method was used for sampling individuals older than 14 years, leading to 507 interviews in Guadeloupe and 508 in Martinique.ResultsThe epidemic lasted 12 weeks in both islands, from August 3 to October 25 in Martinique and from August 17 to November 8 in Guadeloupe. During August and September, estimated attack rate in Martinique was 5.52% (CI95: 5.23–5.83) from the sentinel network versus 8.3% (CI95: 6.0–11.0) from the telephone survey. In Guadeloupe, it was 2.13% (CI95: 1.97–2.24) from the sentinel network versus 6.9% (CI95: 4.8–9.5) from the telephone survey. An equivalent number of confirmed hospitalized cases was observed in the two islands.ConclusionThese results suggest that the sentinel network underestimates ILI incidence in Guadeloupe. According to Emergency Room activity for ILI, it seems possible that ILI incidence was actually higher in Martinique. A lower proportion of swab sampling among ILI hospitalized people could partly explain the observed differences in hospitalization ratio, in severity and in lethality between the two islands.     

世界主要国家和地区传染病监测预警实践进展

新型冠状病毒肺炎大流行再次警示人们,传染病威胁从未真正远去。有效的监测预警作为传染病防控的基石,对全面准确地认识特定传染病暴发流行、提出科学有效的防控策略和措施具有重要意义,因此须持续加强传染病监测预警体系建设。本文对世界主要国家和地区的传染病监测预警实践进行综述,探讨了传染病监测预警领域的发展方向,为进一步加强我国传...     

金华市流行性感冒监测预警曲线的设计及应用

目的为科学有效地预警流感的暴发与流行,制定符合金华市的流感流行早期预警曲线。方法使用全市3所哨点监测医院每周流感样病例(ILI)占门诊病例总数百分比的历史监测数据建立数据库,采用控制图法建立预警模型;在综合2009-2011监测年度流感流行特征和ILI就诊病例中流感估计感染率的基础上,确定判定流感流行的指标及其参考标准;通过计算、比较灵敏度、特异度、阳性预测值、阳性似然比和绘制ROC曲线,选择合适的预警界值。结果选择P75作为流感流行基准曲线预警界值,预警效果相对较好,灵敏度为87.5%,特异度为62.3%;选择P85作为流感流行警戒曲线预警界值,预警效果相对较好,灵敏度为88.9%,特异度为91.0%。结论控制图法可以作为流感预警方法,周ILI%的P75点可以作为流感流行基准预警曲线;周ILI%的P85点可以作为流感流行警戒预警曲线。     

Google Earth在传染病早期预警结果三维可视化中的应用

探讨 Google Eanll(GE)在传染病早期预警结果 三维可视化中的应用.模拟实时监测系统,采用前瞻性时空扫描统计量对2005年上海市、江苏省、浙江省214个区县麻疹病例数据进行逐日前瞻性分析.选择其中部分预警结果,采用GE对其进行三维可视化呈现,完整展示预警结果 中包含的时间、地域、实际发病数、理论发病数等若干相关重要信息.GE在传染病实时监测及早期预警中具有潜在的重要应用价值,可进一步研发将其与网络直报系统和聚集性探测方法 集成的计算机系统.

Abstract：

The purpose of this article was to investigate the application of Google Earth (GE)in the Three Dimensional Visualization(TDV)of the warnings signaled by early warning system of infectious disease.As an example.the prospective space-time scan statistics was used by mimicking daily prospective analyses of bacillary dysentery data from Shanghai municipality,Zhejiang province and Jiangsu province in 2005.Then one of the warnings was picked to illustrate the visualization of GE.GE could vividly display the results in three dimensions containing the complex information including date,areas,observed numbers,expected numbers ere.GE seemed a useful tool for infectious disease surveillance and had potential important values in reflecting the emergency response situation.The development of integrated system which consisted of GE,the infectious disease reporting system and cluster detection methods need to be emphasized for further research.     

学校因病缺课监测预警阈值的研究

目的建立学校因病缺课预警阈值，为学校传染病疫情早期预警工作的开展提供科学依据。方法每日收集学校新增因病缺课人数，剔除多暴发疫情导致的缺课人数，计算常态情况下的班级和学校每日（周）因病缺课人均数（i）和标准差（s），以均数加1～3倍标准差为备选预警阈值，通过实际缺课情况检验确定适宜预警阈值。结果学校日因病缺课人均数在1～3人之间，均数＋3s为预警阈值时较适宜，其中中学为8人，小学为10人；学校周因病缺课人均数在6～11人之间，以均数＋1s为预警阈值时较适宜，其中中学为16人，小学为18人；班级日因病缺课人数最大值均数在2～3人之间；以均数＋1s为预警阈值时较适宜，其中中学为3人，小学为5人；班级周因病缺课人数最大值均数在3～4人之间；以均数＋1s为预警阈值时较适宜，其中中学为6人，小学为7人。结论初步确立中小学日因病缺课预警阈值为8～10人，周预警阈值为16～18人；中小学班级日因病缺课预警阈值为3～5人，周预警闽值为6～7人。     

传染病暴发或流行的探测、监测和预警

传染病继续成为全球发病死亡主要原因之一,影响公众健康生命、社会经济发展甚至国家安全。早期探测重点是及时、敏感地发现传染病暴发流行异常信息,并进行现场调查和核实,也是有效监测、预警系统的前期;有效监测、预警系统能够全面准确地认识特定传染病暴发流行可能发生的事实条件、驱动因素和传播链,并提出科学有效预防控制策略措施;因衡量收集具体数据的资源支撑和价值大小,难以及时、完整、准确地获得流行病学、病原学等数据信息。本文综述传染病早期探测、有效监测、有效预警理论技术,整合利用中国有效传染病监测预警体系和多时空节点触发与多学科渠道监测暴发流行情况、病因、风险、过程和驱动因素的多源数据,构建运行敏感特异、分期度量的中国（急性）传染病监测、预警和响应创新技术体系,为加强新发重大传染病和传染病突发公共卫生事件监测预警、避免应对不力传染病蔓延与防止过度响应资源浪费提供依据。     

传染病预警模式的应用探讨

目的联合应用时间序列ARIMA模型以及控制图原理对传染病监测数据进行分析,探讨切实可行的传染病预警模式,实现对传染病的流行趋势进行预测,以期指导传染病的预防控制工作。方法收集筛选传染病的历史数据,利用时间序列ARIMA模型以及控制图原理,绘制控制图曲线,计算预警界值,预测疾病的流行趋势。结果利用建立的ARIMA模型初步确定疾病的年发病趋势后,可进一步根据绘制的控制图来确定实际疫情的流行趋势,综合传染病的严重性、危害性及可控制性及时作出反应。结论ARIMA模型与控制图法的联合应用,预警精度较高,是较好的传染病疫情预警模式。     

Measles, pertussis, rubella and mumps completeness of reporting. Literature review of estimates for industrialized countries

BACKGROUND: Surveillance data for infectious diseases in industrialized countries have been providing useful epidemiological information for several years. However, surveillance is complex and notifications underestimate the true disease incidence. The goal of this paper is to determine the completeness of reporting of measles, pertussis, rubella and mumps through notification in industrialized countries. METHODS: A thorough literature review of papers published (in French or English) on surveillance data of measles, pertussis, rubella and mumps was undertaken with PUBMED. The review was limited to studies conducted in industrialized countries that quantitatively assessed the completeness of the reporting of these diseases. RESULTS: Fourteen studies published from the 1920s met the inclusion criteria. For measles, the studies suggest that 64-85% of symptomatic patients sought medical care, 13-57% of those were diagnosed with measles and 22-81% of the diagnosed cases were reported for a completeness of reporting ranging from 7% to 63% between 1920 and 1980 and 3% to 41% in recent years. For pertussis, it was estimated that 49-59% of symptomatic patients sought medical care, 12% of those were diagnosed and 19-47% of the diagnosed cases were reported for a completeness of reporting ranging from 5% to 25% between 1920 and 1980 and from 3% to 12% in recent years. Very few studies on rubella and mumps were found and none allowed the determination of the global completeness of reporting. CONCLUSION: Reporting has been found to be considerably incomplete. Continued efforts to improve the recognition and reporting of these diseases are needed.