National enhanced surveillance of meningococcal disease in England,Wales and Northern Ireland,January 1999-June 2001

Enhanced surveillance of meningococcal disease (ESMD) was implemented nationally across ten regions of England, Wales and Northern Ireland from 1 January 1999. It aims to deliver more sensitive surveillance than laboratory reporting by including clinically diagnosed but laboratory unconfirmed cases. Consultants in Communicable Disease Control (CsCDC) report all clinically diagnosed cases of meningococcal disease (MD) to the Regional Epidemiologist in the relevant regional unit of the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). These reports are reconciled with laboratory data from the PHLS Meningococcal Reference Unit and then forwarded to the national CDSC where further reconciliation with laboratory data takes place. In addition, CsCDC are asked to report any clusters of MD that occur. Between 1 January 1999 and 30 June 2001, 12,074 cases of MD were ascertained through ESMD. The majority (57%) were laboratory confirmed. The estimated incidence of MD fell between 1999 and 2001 from 9.2 to 8.0 per 100,000 population. Of laboratory confirmed cases, the number of cases of serogroups B and W135 increased and of serogroup C and of ungrouped meningococcal infection decreased. Variation between regions was considerable and deserves further investigation. Of 11,522 cases with a reported clinical diagnosis, 53.6% were diagnosed as septicaemia, 32.6% as meningitis, 12.5% as both septicaemia and meningitis, and 13% had other invasive MD. Between 1 January 1999 and 30 June 2001 698 deaths were reported, an overall case fatality rate (CFR) of 5.8%; 567 deaths were in confirmed cases and 131 probable (CFR 8.2% and 2.5%, respectively). CFR was higher in serogroup C (13.5%) than B (5.8%). No peak in serogroup C meningococcal infection occurred in the winter of 2000/1 and no clusters of serogroup C meningococcal infection were reported in the first half of 2001. ESMD provides information about the epidemiology of MD that is more complete than statutory notification and laboratory surveillance and is useful for evaluating the impact of the meningococcal serogroup C vaccination programme and of the other non-vaccine preventable serogroups.     

General outbreaks of infectious intestinal disease (IID) in hospitals,England and Wales, 1992-2000

Between 1992 and 2000, 26.6% (1,396/5,257) of all general outbreaks of infectious intestinal disease (IID) reported to the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC) occurred in hospitals. Over 29,000 patients and staff were affected and the mortality risk was higher than for outbreaks in other settings [relative risk 2.00 (95% CI: 1.52-2.63) P<0.001]. Person-to-person spread was the predominant mode of transmission. The mortality risk was highest in foodborne disease outbreaks [relative risk 3.22 (95% CI: 1.41-7.36); P=0.003]. Most outbreaks occurred between November and April. The pathogens most frequently reported were Norwalk-like virus (NLV) (54%) and Clostridium difficile (12.6%). These findings emphasize the public health importance of outbreaks of IID in hospitals, especially during the winter when pressures on hospitals are at their height.     

Milkborne general outbreaks of infectious intestinal disease,England and Wales, 1992-2000

From 1 January 1992 to 31 December 2000, 27 milkborne general outbreaks of infectious intestinal disease (IID) were reported to the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). These outbreaks represented a fraction (2%) of all outbreaks of foodborne origin (N = 1774) reported to CDSC, but were characterized by significant morbidity. Unpasteurized milk (52%) was the most commonly reported vehicle of infection in milkborne outbreaks, with milk sold as pasteurized accounting for the majority of the rest (37%). Salmonellas (37%), Vero cytotoxin-producing Escherichia coli (VTEC) O157 (33%) and campylobacters (26%) were the most commonly detected pathogens, and most outbreaks were linked to farms (67%). This report highlights the importance of VTEC O157 as a milkborne pathogen and the continued role of unpasteurized milk in human disease.     

General outbreaks of infectious intestinal disease linked with red meat,England and Wales, 1992-1999

Between 1992 and 1999, 1,426 foodborne general outbreaks of infectious intestinal disease (IID) were reported to the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). Sixteen percent were linked with the consumption of red meat. Over 5,000 people were affected, with 186 hospital admissions and nine deaths. Beef (34%) and pig meat (32%) were the most frequently implicated meat types, with lamb implicated in 11% of outbreaks. The organisms most frequently reported were Clostridium perfringens (43.4%) and salmonellas (34.3%). During the summer, outbreaks were mainly of Salmonella spp. and attributed to the consumption of pig meat. In December, outbreaks of C. perfringens linked with beef predominated. Most outbreaks occurred as a result of food cooked on commercial catering premises (46%). The highlight of this surveillance period is a fall in the number of outbreaks linked with foods containing red meat. This corresponds with a steady decline in red meat consumption over the last two decades, as well as a transient though marked decline in the purchase and consumption of red meat in the UK during the BSE crisis in the early to mid 1990s. As cited in the Pennington Report, further reducing the morbidity and mortality from red meat outbreaks means targeting meat production at various points along the food chain from abattoir and butchering, to cooking and holding of cooked food, especially on commercial catering premises.     

General outbreaks of infectious intestinal disease linked with salad vegetables and fruit,England and Wales, 1992-2000

Between 1992 and 2000, 1,518 foodborne general outbreaks of infectious intestinal disease (IID) were reported to the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC), of which 83 (5.5%) were associated with the consumption of salad vegetables or fruit (SVF). The pathogens most frequently reported were salmonellas (41.0%) and Norwalk-like virus (NLV) (15.7%). In total 3,438 people were affected; 69 were admitted to hospital and one person died. Most outbreaks were linked to commercial catering premises (67.5%). Three community outbreaks, of Salmonella enterica serovar Typhimurium Definitive Phage Type (DT) 104, S. Typhimurium DT 204b and Shigella sonnei infection, were found to be associated with lettuce contaminated at source, and these accounted for 501 (14.6%) cases. The latter two outbreaks were international, involving several European countries. This demonstrates how contamination of SVF during production/processing can result in major, geographically widespread, outbreaks of infection with serious public health consequences.     

Enhanced surveillance of meningococcal disease in the West Midlands: 1996 to 1998

Surveillance of meningococcal disease is vital if we are to respond to a changing burden of disease, but current sources of routine data suggest different trends. A scheme for enhanced surveillance of meningococcal disease began in the West Midlands in January 1996 using several data sources, including case reporting from consultants in communicable disease control, data from the PHLS Meningococcal Reference Unit, and monitoring of statutory notifications and laboratory reports. One thousand two hundred and twenty-eight cases of probable meningococcal infection were identified in three years (1996-1998), 594 of which were laboratory confirmed. Routine data for the same period yielded smaller totals--920 notifications and 412 laboratory reports--suggesting that these sources underestimate incidence by 25% to 30%. Diagnosis by polymerase chain reaction became increasingly important, and accounted for 38% of confirmed cases in 1998. A significant excess of male cases was observed (p < 0.01), most obvious in children under 5 years of age. There was no increase in N. meningitidis C2a strains, which had been identified as a threat nationally. A national system of enhanced surveillance has now been set up to inform programmes that aim to reduce the burden of meningococcal infection.     

Training in communicable disease epidemiology: the contribution of the Communicable Disease Surveillance Centre of the Public Health Laboratory Service

Summary The training and teaching functions of the Communicable Disease Surveillance Centre (CDSC) of the Public Health Laboratory Service (PHLS) are described and a nationally coordinated short training scheme in the epidemiology and control of communicable disease for senior registrars in general community medicine is proposed. This training scheme, coordinated by CDSC Colindale and initially based there, will involve the participation of medical officers for environmental health and microbiologists in England and Wales as well as specialist community physicians of CDSC. CDSC also provides higher specialist training for senior registrars intending to take up consultant posts in communicable disease epidemiology. The three year programme, the main elements of which are communicable disease epidemiology, general community medicine, microbiology and clinical infectious disease, is briefly described.     

Evolution of a laboratory based system for investigating outbreaks of infectious intestinal disease

In 1995 Preston Public Health Laboratory introduced an incident logging system intended to improve the investigation of suspected outbreaks of infectious intestinal disease. A unique incident log (Ilog) number assigned and issued to the reporting individual and other interested parties when the laboratory is informed of a potential outbreak is used to identify all associated specimens submitted to the laboratory and is quoted in all communications about the incident. The results are reviewed formally each month. Between January 1995 and December 1998, 349 potential outbreaks of infectious intestinal disease were investigated, 325 of which were considered to be general outbreaks. Small round structured viruses were identified in 45% of these outbreaks, salmonellas in 8%, and no pathogens in 35%. Data from the national surveillance scheme for general outbreaks of infectious intestinal disease included 104 general outbreaks in 1996 and 1997 for the entire North West region, but our laboratory alone reported 184 general outbreaks during that period. The Ilog system is a simple and effective means for reviewing data from outbreaks, and helps to coordinate their investigation.     

Laboratory diagnosis of Clostridium difficile-associated disease in the Republic of Ireland: a survey of Irish microbiology laboratories

The Health Protection Surveillance Centre (HPSC) established a group to produce national guidelines for Clostridium difficile in Ireland in 2006. A laboratory questionnaire was distributed to determine current C. difficile diagnostic practices. Twenty-nine out of 44 laboratories providing C. difficile diagnostic services to 34 hospitals responded. Twenty-five out of 29 (86%) laboratories processed specimens for C. difficile and four (13.8%) forwarded specimens to another laboratory. Sixteen laboratories (64%) processed specimens for other healthcare facilities. None routinely examined stool for C. difficile, seven (28%) examined specimens only when requested to do so and 18 (72%) used specific selection criteria, including testing all liquid stools (39%), all nosocomial diarrhoea (44%), specific clinical criteria (28%) and history of antibiotic therapy (22%). All tested stool directly for C. difficile toxin with a variety of enzyme immunoassays, with 24 (96%) detecting both toxin A and B and one detecting toxin A only. Three (12%) laboratories used cytotoxicity assays; none used polymerase chain reaction and six (24%) laboratories performed C. difficile culture but only under specific circumstances. Seven (28%) laboratories had isolates typed during outbreaks, but none had the facilities to do so on-site. The HPSC group will produce national recommendations for laboratory diagnosis, surveillance and management of C. difficile infection. Since there are marked differences in diagnostic practices throughout the country and no national reference laboratory, the implementation of these recommendations will have cost implications that will need to be addressed.     

Active and passive immunization against Clostridium difficile diarrhea and colitis

Clostridium difficile, a gram-positive bacterium, is the major cause of hospital-acquired infectious diarrhea and colitis in industrialized nations. C. difficile colonization results from antibiotic administration and subsequent loss of protection provided by intestinal flora. C. difficile induced-colitis is caused by the release of two exotoxins, toxin A and B. Host factors including advanced age, pre-existing severe illness and weakened immune defenses predispose individuals to symptomatic infection. The generation of antibody responses to toxin A through natural exposure is associated with protection from disease. In addition, an inability to acquire immunity to toxin A puts individuals at risk for recurrent and/or severe disease. Immunological approaches for the management of this disease are being developed which could reduce the reliance on antibiotics for treatment and allow for re-establishment of the natural barrier provided by an intact commensal flora. An active vaccine and various immunotherapeutic strategies under evaluation may prove to be effective against severe or relapsing C. difficile infection.     

Public health implications of campylobacter outbreaks in England and Wales, 1995-9: epidemiological and microbiological investigations

Although campylobacter has been the most commonly recognized bacterial cause of gastrointestinal infection in England and Wales since 1981, there are few reported campylobacter outbreaks. Of the 2374 general outbreaks of infectious intestinal disease reported to CDSC between 1995 and 1999, for which an aetiological agent was identified, campylobacter accounted for only 50 (2%). Foodborne transmission was identified in 35 outbreaks and the majority took place in commercial catering establishments; waterborne transmission was responsible for a further four outbreaks. Isolates of Campylobacter jejuni were referred for typing from 25 outbreaks. In 13 outbreaks all isolates were the same subtype, as defined by serotype and phage type, while in the remainder more than one campylobacter subtype was involved.     

Surveillance of small round structured virus (SRSV) infection in England and Wales, 1990-5.

Data from the national surveillance scheme for general outbreaks of intestinal disease, and the national laboratory reporting scheme were used to describe the epidemiology of small round structured virus (SRSV) infections in England and Wales. Between 1990 and 1995, there were 7492 laboratory reports of SRSV. Rates of reported illness were highest among infants, young children and the elderly. During 1992-5, some 707 SRSV outbreaks were reported. Outbreaks in hospital wards and residential facilities for the elderly accounted for 76% of the total, and annual numbers increased more than sixfold over the study period. There were wide regional variations in the numbers of SRSV outbreaks and laboratory reports. Both sporadic cases and outbreaks in the community are likely to be underestimated, but these passive surveillance systems provide an insight into the burden of SRSV infection among the institutionalized elderly.     

The PHLS response to a pandemic of influenza

This document sets out the Public Health Laboratory Service (PHLS) action plan for responding to an influenza pandemic. The plan entails, in phase 0, interpandemic surveillance by the Communicable Disease Surveillance Centre (CDSC) and the Enteric & Respiratory Virus Laboratory (ERVL) of the Central Public Health Laboratory (CPHL), as well as maintenance by Area & Regional (A & R) Public Health Laboratories of updated diagnostic techniques for influenza. In phase 1 (the emergence of a shifted influenza virus strain) a Pandemic Working Group will be convened to consider what action by PHLS is necessary. In phase 2 (pandemic influenza outside UK) the pre-defined roles for PHLS laboratories and CDSC will be adopted. When a pandemic is imminent in the United Kingdom (phase 3) the Working Group will co-ordinate PHLS activities and the Director of the Service will assess what special studies should be implemented. In phase 4, when the pandemic has reached the UK, the action plan sets out comprehensive measures that will be taken by CDSC, ERVL and A & R Laboratories to gather and collate information, provide DoH with weekly surveillance data and develop recommendations for prophylaxis, clinical management and treatment. When influenza activity has returned to background levels (phase 5) a report will be drafted by the Working Group prior to it being stood down by the Director of the Service. The response is summarised in tabular form in Table 1.Reproduced by kind permissin of thePHLS Microbiology Digest (first published 1993, 10: 147–154)     

Outbreaks of waterborne infectious intestinal disease in England and Wales, 1992-5.

Following the introduction of an improved surveillance system for infectious intestinal disease outbreaks in England and Wales, the Public Health Laboratory Service Communicable Disease Surveillance Centre received reports of 26 outbreaks between 1 January 1992 and 31 December 1995 in which there was evidence for waterborne transmission of infection. In these 26 outbreaks, 1756 laboratory confirmed cases were identified of whom 69 (4%) were admitted to hospital. In 19 outbreaks, illness was associated with the consumption of drinking water from public supplies (10 outbreaks) or private supplies (9 outbreaks). The largest outbreak consisted of 575 cases. In 4 of the remaining 7 outbreaks, illness was associated with exposure to swimming pool water. Cryptosporidium was identified as the probable causative organism in all 14 outbreaks associated with public water supplies and swimming pools. Campylobacter was responsible for most outbreaks associated with private water supplies. This review confirms a continuing risk of cryptosporidiosis from chlorinated water supplies in England and Wales, and reinforces governmental advice to water utilities that water treatment processes should be rigorously applied to ensure effective particle removal. High standards of surveillance are important for prompt recognition of outbreaks and institution of control measures. As microbiological evidence of water contamination may be absent or insufficient to implicate a particular water supply, a high standard of epidemiological investigation is recommended in all outbreaks of suspected waterborne disease.     

Enhancing surveillance of cryptosporidiosis: test all faecal specimens from children

The heightened risk of waterborne cryptosporidiosis, associated with heavy rainfall in autumn 2000, prompted us to survey laboratory practice in the South East Region of England in testing faecal specimens for Cryptosporidium spp. oocysts and reporting to the Public Health Laboratory Service Communicable Disease Surveillance Centre (PHLS CDSC). Varied practices were found. Ideally, all faecal specimens should be tested, but where laboratories are unable to do so, screening all faecal specimens from children age 15 years or younger would improve surveillance and could probably be accomplished with minimal additional resources.     

Enhanced surveillance scheme for suspected meningococcal disease in five regional health authorities in England: 1998

Enhanced surveillance of meningococcal disease (ESMD) began in five English regions on 1st January 1998. The aims of the scheme were to obtain accurate incidence data and develop a robust surveillance system with which to monitor the impact of a new meningococcal serogroup C conjugate vaccine. During 1998, 2,314 suspected cases of meningococcal disease were identified. The majority (84%) was classified as invasive meningococcal disease, with infection of N. meningitidis confirmed in 66%. Sixteen per cent of suspected cases were subsequently given an alternative diagnosis. Age differences between those classified as meningococcal disease and those not, implied a higher index of suspicion of meningococcal disease in younger children. Regions with high rates of meningococcal disease were due to a higher rate of serogroup C. ESMD increased ascertainment of meningococcal disease and deaths. Cases were 34% greater than identified through statutory notifications, an additional 6.8% confirmed infections were identified than were reported to the PHLS Meningococcal Reference Unit (MRU) and deaths were 24% greater than death registrations. These data were used to inform the national meningococcal serogroup C conjugate vaccination programme in England and Wales. In 1999 ESMD was extended to all regions of England, Wales and Northern Ireland.     

2010年深圳市学校与托幼机构传染病爆发疫情分析

目的了解2010年深圳市学校与托幼机构传染病爆发疫情的流行病学特征。方法应用描述性流行病学方法对深圳市2010年学校传染病爆发疫情进行分析。结果 2010年深圳市学校与托幼机构传染病爆发疫情263起,其中以小学最为常见,占43.4%;传染病爆发疫情以3、4、9月为多,占70%以上;爆发疫情为乙类、丙类和非法定传染病,主要病种为流感、手足口病和急性出血性结膜炎;在263起传染病爆发疫情中,经肠道传播的占60.8%,其次为呼吸道传播占39.2%。发病2 610例,波及人数39 149人,罹患率为6.7%。结论 2010年深圳市学校与托幼机构传染病爆发疫情主要为丙类传染病,传播途径以肠道传播为主,经呼吸道传播为次;高发人群仍然是幼儿及小学生。     

Reproductive health for refugees by refugees in Guinea IV: Peer education and HIV knowledge, attitudes, and reported practices

Fragile states are home to a sixth of the world's population, and their populations are particularly vulnerable to infectious disease outbreaks. Timely surveillance and control are essential to minimise the impact of these outbreaks, but little evidence is published about the effectiveness of existing surveillance systems. We did a systematic review of the circumstances (mode) of detection of outbreaks occurring in 22 fragile states in the decade 2000-2010 (i.e. all states consistently meeting fragility criteria during the timeframe of the review), as well as time lags from onset to detection of these outbreaks, and from detection to further events in their timeline. The aim of this review was to enhance the evidence base for implementing infectious disease surveillance in these complex, resource-constrained settings, and to assess the relative importance of different routes whereby outbreak detection occurs. We identified 61 reports concerning 38 outbreaks. Twenty of these were detected by existing surveillance systems, but 10 detections occurred following formal notifications by participating health facilities rather than data analysis. A further 15 outbreaks were detected by informal notifications, including rumours. There were long delays from onset to detection (median 29 days) and from detection to further events (investigation, confirmation, declaration, control). Existing surveillance systems yielded the shortest detection delays when linked to reduced barriers to health care and frequent analysis and reporting of incidence data. Epidemic surveillance and control appear to be insufficiently timely in fragile states, and need to be strengthened. Greater reliance on formal and informal notifications is warranted. Outbreak reports should be more standardised and enable monitoring of surveillance systems' effectiveness.