Outbreak Control Team Research Articles

Neonatal staphylococcal scalded skin syndrome: clinical and outbreak containment review

Staphylococcal scalded skin syndrome (SSSS) is a toxin-mediated exfoliating skin condition predominated by desquamation and blistering. Neonatal outbreaks have already been reported; however, our outbreak highlights the potential for SSSS following neonatal health promotion measures such as intra-muscular vitamin K administration and metabolic screening (heel prick) as well as effective case containment measures and the value of staff screening. Between February and June 2007, five confirmed cases of neonatal SSSS were identified in full-term neonates born in an Irish regional maternity hospital. All infants were treated successfully. Analysis of contact and environmental screening was undertaken, including family members and healthcare workers. Molecular typing on isolates was carried out. An outbreak control team (OCT) was assembled and took successful prospective steps to prevent further cases. All five Staphylococcus aureus isolates tested positive for exfoliative toxin A, of which two distinct strains were identified on pulsed-field gel electrophoresis analysis. Two cases followed staphylococcal inoculation during preventive measures such as intra-muscular vitamin K administration and metabolic screening (heel prick). None of the neonatal isolates were methicillin resistant. Of 259 hospital staff (70% of staff) screened, 30% were colonised with S. aureus, and 6% were positive for MRSA carriage. This is the first reported outbreak of neonatal SSSS in Ireland. Effective case containment measures and clinical value of OCT is demonstrated. Results of staff screening underlines the need for vigilance and compliance in hand disinfection strategies in maternity hospitals especially during neonatal screening and preventive procedures.

A Study of 279 General Outbreaks of Gastrointestinal Infection in the North-East Region of England

All outbreaks of infectious intestinal disease reported to the authorities were entered on a computer database with outbreak control teams being established to investigate larger or more significant incidents. The outbreak database and, when set up, the notes of outbreak team meetings were examined for the 279 outbreaks reported in a three-year period (2003–2005). Faeces specimens submitted as part of an outbreak were examined for microbial pathogens and the results cross-matched to the outbreak number. Almost half of the general outbreaks reported (137) occurred in long-term care facilities for the elderly, 51 outbreaks were recorded in hospitals and 31 occurred in the wider community. In 76 outbreaks no specimen was logged. A microbial cause was confirmed in about one-third of outbreaks, with noroviruses being the most common (19%). Salmonellas accounted for 12 of the 21 community outbreaks linked to social events and all were foodborne. Suggestions for improving notification and surveillance are discussed.

Tuberculosis symptom screening among new prisoners in two Greater Manchester prisons

The incidence of tuberculosis (TB) has increased in the UK over the last 15 years. In England, the TB rate in 2006 was 15.5 per 100,000 of the population. The rates varied in different parts of the country, with London having the highest rate (44.8 per 100,000). Greater Manchester had the highest rate in the northwest of England (16.6 per 100,000), and there were variations within the county, with Manchester having the highest rate (37.4 per 100,000) and Bury having the lowest rate (2.2 per 100,000).1,2 A recent study set in London reported that TB rates in the prison population are much higher than average (208 per 100,000).3 Late diagnosis, overcrowding, poor ventilation and repeated prison transfer of infectious individuals encourages the spread of infectionwithin the prison environment. TB incidents in prisons are challenging to manage and cause significant anxiety in prisoners and staff. A recent community outbreak of isoniazid-resistant TB in North London resulted in the first published report of TB transmission in a UK prison. The outbreak control team recommended, among other things, that standardized symptom assessment should be undertaken on reception, and adequate isolation facilities should be provided. In England, there is close liaison between the National Health Service (NHS) and the prison service, and this facilitates a partnership approach to developing policy relating to prison health. National guidelines were produced by the National Institute for Health and Clinical Excellence on TB in 2006, and several recommendations were made relating to prison health, including that prisoners should undergo TB symptom screening on each entry to the prison system.6 In line with this, a northwest prison TB control policy was developed jointly by the Northwest Regional TB Group

Norovirus outbreak associated with a hotel in the west of Ireland, 2006

An outbreak of gastrointestinal disease (nausea, vomiting or diarrhoea) occurred among a party of wedding guests, staff and other guests in a hotel in the west of Ireland, in October 2006. Upon notification, a multi-disciplinary outbreak control team was convened to investigate and control the outbreak. In all, 98 people were ascertained ill. The median duration of illness was 48 hours. The attack rate ranged between 48 and 85%. The hotel voluntarily notified health authorities and co-operated fully with investigation and control measures. Strict prevention and control measures were instituted promptly, including air ventilation, enhanced hand hygiene, isolation of cases, temporary "cooked food only", temporary alternative accommodation and specialised cleaning. Three cases of norovirus infection were laboratory-confirmed. There was no evidence of food- or water-borne transmission. Clinical and epidemiological findings indicated person-to-person transmission of norovirus. This report highlights the potential for large social gatherings to facilitate the spread of viral gastroenteritis by person-to-person transmission and via contaminated environment. Effective community management of this outbreak appears to have prevented its having an impact on local acute hospital services. The authors conclude that in addition to the existing national guidelines on the management of outbreaks of norovirus in healthcare settings, agreed guidelines for the management of norovirus outbreaks in the hotel and tourism industry are needed in Ireland.

Investigation of an outbreak of Legionnaires’ disease: Hereford, UK 2003

This report describes the investigation and control of a community outbreak of Legionnaires' disease in Hereford, UK, in November 2003. Outbreak investigation consisted of epidemiological survey, identification and environmental investigation of potential sources, microbiological analysis of clinical and environmental samples and mapping the location of potential sources and the movement and residence of cases. Each identified source was allocated a 'composite score' based on different zones of exposure and wind direction. Altogether, 28 cases were identified, with an overall case fatality rate of 7%. All cases had epidemiological links to Hereford city centre. The 'composite score' identified a cluster of cooling towers as being the most likely source of the outbreak. Environmental samples from one of the cooling towers in the cluster and clinical samples from two patients were positive for Legionella pneumophilia serogroup 1 and were indistinguishable by molecular sub-typing. In this outbreak, the use of microbiological, environmental and epidemiological techniques facilitated the rapid identification of a cooling tower as the source of this outbreak. This study illustrates the continuing importance of cooling towers as a source of Legionnaires' disease and the utility of obtaining and comparing both clinical and environmental samples.

Identifying outbreaks of sexually transmitted infection: who cares?

BackgroundCurrent routine surveillance schemes for sexually transmitted infections (STIs) in the United Kingdom (UK) are not designed for outbreak identification. Recognising STI outbreaks, therefore, depends almost entirely on the alertness of health professionals. The objective of this study was to explore health professionals' knowledge of, and attitudes towards, identification and investigation of STI outbreaks in Wales.MethodsWe conducted a cross-sectional survey in Wales in June 2005, and sent a questionnaire to consultants of genitourinary medicine (GUM, n = 11), a consultant microbiologist from each laboratory (n = 14), all consultants in communicable disease control (n = 5), and to epidemiologists of the National Public Health Service (n = 4).Results26 (76%) of 34 survey recipients responded. Of these, 17 (65%) ranked the investigation of STI outbreaks as important or very important, and 19 (73%) perceived participation in the investigation of an STI outbreak as part of their responsibility. Only six (25%) respondents had actively searched their computer system or patient records for a possible STI outbreak in the previous twelve months, and 15 (63%) had never looked for an outbreak. Of seven GUM physicians who said they had identified at least one STI outbreak, three had never informed public health authorities.ConclusionPrompt identification and coordinated investigation of outbreaks, usually through a multidisciplinary outbreak control team, is central to the control of many infectious diseases. This does not appear to be the case for STIs, which we believe represents a lost opportunity to reduce transmission. Besides improved surveillance methods, a change in culture towards STI outbreaks is needed among health professionals in Wales.

Impact of a salmonella outbreak investigation in a maximum security Scottish prison

Following notification of a stool sample positive for Salmonella from an inmate of a maximum security prison a concerted multidisciplinary public health response was undertaken. Lanarkshire NHS Board Health Protection Team (HPT) held one Problem Assessment Group Meeting and two Outbreak Control Team Meetings. The outbreak period spanned three weeks during which there were three confirmed and six probable cases of Salmonella enteritidis PT4 in prison inmates. The source was not identified despite thorough investigation, however the outbreak control team (OCT) was able to identify key recommendations around general hygiene, shared toilet facilities and storage of cooked food in cells. The outbreak stimulated closer working arrangements between the prison medical services and the local HPT. Co-operation during the outbreak investigation and subsequent to the OCT report facilitated both operational changes at the prison and improvements to the management of infection control across the Scottish Prison Service.

Human Vero cytotoxigenic Escherichia coli (VTEC) O157 infection linked to birds

Vero cytotoxin-producing Escherichia coli O157 (VTEC O157) infections are a threat to public health. VTEC O157 has been isolated from gulls but evidence of transmission to humans from birds has not been reported. We recount an incident of VTEC O157 infection affecting two sibling children who had no direct contact with farm animals. An outbreak control team was convened to investigate the source of infection, its likely mode of transmission, and to advise on control measures. Human and veterinary samples were examined and the human isolates were found to be identical to an isolate from a sample of bird (rook) faeces. Cattle, rabbit and environmental samples were negative. This report provides evidence that birds may act as intermediaries for human infection with VTEC O157.

Herramientas para afrontar las situaciones de crisis en un brote de gastroenteritis aguda en un colegio público

We present our reflections on the management of an acute gastroenteritis outbreak in a public school, which caused a public health crisis, and the conclusions drawn from this experience. The methodology of strengths, weaknesses, opportunities, and threats (SWOT) analysis was used. This article describes the epidemiology of the incident and the policy decisions made, but focuses on operational aspects of outbreak management. The experience of the outbreak control team, liaison with other organizations, and data management are discussed. The difficulties encountered by the outbreak team related to delay in declaring in the outbreak, lack of training in some of the entities involved, and incorrect use of the surveillance circuits. Current protocols and specific action plans for the management of outbreaks should be improved through selfevaluation and updating of resources and knowledge.

The epidemiology of infectious syphilis in the Republic of Ireland.

In response to the increasing numbers of syphilis cases reported among men having sex with men (MSM) in Dublin, an Outbreak Control Team (OCT) was set up in late 2000. The outbreak peaked in 2001 and had largely ceased by late 2003. An enhanced syphilis surveillance system was introduced to capture data from January 2000. Between January 2000 and December 2003, 547 cases of infectious syphilis were notified in Ireland (415 were MSM). Four per cent of cases were diagnosed with HIV and 15.4% of cases were diagnosed with at least one other STI (excluding HIV) within the previous 3 months. The mean number of contacts reported by male cases in the 3 months prior to diagnosis was 4 (range 0-8) for bisexual contacts and 6 for homosexual contacts (range 1-90). Thirty one per cent of MSM reported having had recent unprotected oral sex and 15.9% of MSM reported having had recent unprotected anal sex. Sixteen per cent of cases reported having had sex abroad in the three months prior to diagnosis. The results suggest that risky sexual behaviour contributed to the onward transmission of infection in Dublin. The outbreak in Dublin could be seen as part of a European-wide outbreak of syphilis. The rates of co-infection with HIV and syphilis in Ireland are comparable with rates reported from other centres. There is a need to improve surveillance systems in order to allow real time evaluation of interventions and ongoing monitoring of infection trends.

An outbreak of Salmonella enteritidis phage type 34a infection associated with a Chinese restaurant in Suffolk, United Kingdom.

BackgroundOn 30th July 2002, the Suffolk Communicable Disease Control Team received notifications of gastrointestinal illness due to Salmonella Enteritidis in subjects who had eaten food from a Chinese restaurant on 27th July. An Outbreak Control Team was formed resulting in extensive epidemiological, microbiological and environmental investigations.MethodsAttempts were made to contact everybody who ate food from the restaurant on 27th July and a standard case definition was adopted. Using a pre-designed proforma information was gathered from both sick and well subjects. Food specific attack rates were calculated and two-tailed Fisher's exact test was used to test the difference between type of food consumed and the health status. Using a retrospective cohort design univariate Relative Risks and 95% Confidence Intervals were calculated for specific food items.ResultsData was gathered on 52 people of whom 38 developed gastrointestinal symptoms; 16 male and 22 female. The mean age was 27 years. The mean incubation period was 30 hours with a range of 6 to 90 hours. Food attack rates were significantly higher for egg, special and chicken fried rice. Relative risk and the Confidence interval for these food items were 1.97 (1.11–3.48), 1.56 (1.23–1.97) and 1.48 (1.20–1.83) respectively. Interviews with the chef revealed that many eggs were used in the preparation of egg-fried rice, which was left at room temperature for seven hours and was used in the preparation of the other two rice dishes. Of the 31 submitted stool specimens 28 tested positive for S Enteritidis phage type 34a and one for S Enteritidis phage type 4.ConclusionIn the absence of left over food available for microbiological examination, epidemiological investigation strongly suggested the eggs used in the preparation of the egg-fried rice as the vehicle for this outbreak. This investigation highlights the importance of safe practices in cooking and handling of eggs in restaurants.

A cluster of leptospirosis cases in canoeists following a competition on the River Liffey.

On 6 November 2001, a possible case of leptospirosis was notified in a canoeist following a white-water event on the River Liffey. It emerged that a second race participant was also a possible case. An outbreak control team coordinated the epidemiological investigation, laboratory investigation, environmental assessment, communication and control measures. A cluster of six laboratory-confirmed cases of leptospirosis, serologically Leptospira interrogans serogroup Icterohaemorrhagiae was found. The attack rate was 9.2% (6/65). Fever, chills, red eyes and shortness of breath were significantly associated with being a confirmed case. Five cases were hospitalized. Swallowing more than one mouthful of water was associated with an increased risk of developing leptospirosis. Increased rainfall and release of hydroelectric water may have contributed to this outbreak. A multidisciplinary approach and use of the Internet and e-mail facilitated rapid and effective communication.

E. coli O157 phage type 21/28 outbreak in North Cumbria associated with pasteurized milk.

In March 1999, a large community outbreak of Escherichia coli O157 infection occurred in North Cumbria. A total of 114 individuals were reported to the Outbreak Control Team (OCT); 88 had laboratory confirmed E. coli O157. Twenty-eight (32%) of the confirmed cases were admitted to hospital, including three children (3.4%) with haemolytic uraemic syndrome. There were no deaths. A case-control study found that illness was strongly associated with drinking pasteurized milk from a local farm (P = <0.0001) on single variable analysis. Microbiological investigations at the farm revealed E. coli O157 phage type (PT) 21/28 VT 2 which was indistinguishable from the human isolates by pulsed field gel electrophoresis. At the time of occurrence this was the largest E. coli O157 outbreak in England and Wales and the first E. coli O157 PT 21/28 VT 2 outbreak associated with pasteurized milk. This outbreak highlights lessons to be learnt regarding on-farm pasteurization.

Convalescent excretion of Salmonella enteritidis in infants.

To review the excretion of Salmonella enteritidis PT4 in the faeces of infants involved in a point-source outbreak in a nursery, and to relate these findings to advice given by the Outbreak Control Team (OCT). Retrospective laboratory-based survey. Infection with S. enteritidis PT4 was microbiologically confirmed in 33 primary cases and one secondary case. Of the faeces submitted 4 weeks from exposure, 96% remained positive. None of the infants was symptomatic by this time, and none received antimicrobial treatment. Two infants aged less than 1 year were still excreting 22 weeks after the onset of the outbreak. As for other serotypes, S. enteritidis PT4 causes prolonged symptomless excretion after infection, particularly in infants aged less than 1 year. Infection control measures, including exclusion criteria, may need to be modified as an outbreak progresses.

A pseudo-outbreak of salmonellosis.

during July 1991, a single laboratory reported an increased number of an unusual salmonella isolate. An outbreak control team was convened. A case was defined as an individual with diarrhoea from whose faecal sample Salmonella hadar was isolated after 1 July 1991. By 30 July, 90 isolates had been identified and 57 persons interviewed including 39 primary cases. Interviews failed to identify any common features among the cases. A review of the laboratory procedures revealed that the selenite enrichment medium was inoculated using the spoon from the stool collection kit after it was used to emulsify the faecal sample with saline for microscopy. Salmonella hadar was isolated from this saline. Once this practice was stopped, no further isolates of S. hadar were made. This pseudo-outbreak is a powerful reminder to verify the existence of an outbreak, especially when epidemiological data are inconsistent.

Management and control of a large outbreak of diarrhoea due to Clostridium difficile

In the six-month period 1 November 1991 to 1 May 1992 175 patients developed diarrhoea due to Clostridium difficile in three hospitals in Manchester, UK. Most patients (90%) were over 60 years old and had been admitted to acute geriatric or medical wards with other illnesses. Infection is thought to have contributed to 17 deaths. Twenty-two patients relapsed clinically after antibiotic treatment. The outbreak began in one ward and affected 15 patients and two nurses. During the following months cases occurred on 34 wards. The pattern of spread suggested that a ward index case was followed by several secondary cases. Pyrolysis mass spectrometry showed that 79% of isolates of C. difficile belong to a single cluster and this putative outbreak strain also extensively colonizes the hospital environment. It was also responsible for a smaller outbreak in 1991 and many ‘sporadic’ cases in our hospitals before then. An outbreak control team was convened at an early stage and expert opinion co-opted. Infection control measures included: intensive education of staff; increased vigilance; strict enteric precautions; cohort nursing in a designated ward; rigorous cleaning procedures including emptying and ‘deep’ cleaning of wards where several cases had occurred; restriction of staff and patient movement; and restriction of antibiotic use. Subsequent to these measures there has been a substantial and sustained decrease in the number of new cases.