A large outbreak of measles in the West Midlands, England, 2017-2018: descriptive epidemiology, control measures and lessons learnt.

In November 2017, eight confirmed measles cases were reported to Public Health England from a hospital in the West Midlands. A multidisciplinary Incident Management Team (IMT) was established to determine the extent of the problem and coordinate an outbreak response. Between 1 November 2017 and 4 June 2018, a total of 116 confirmed and 21 likely measles cases were linked to this outbreak; just under half (43%) were aged over 15 years of age. Fifty-five of the confirmed cases were hospitalised (48%) and no deaths were reported. At the start of the outbreak, cases were mostly individuals of Romanian origin; the outbreak subsequently spread to the wider population. Over the 8-month response, the IMT conducted the following control measures: extensive contact tracing, immediate provision of post-exposure prophylaxis, community engagement amongst specific high-risk groups, MMR awareness raising including catch-up campaigns and enhanced vaccination services at selected GP surgeries. Key challenges to the effective control measures included language difficulties limiting community engagement; delays in diagnosis, notification and appropriate isolation of cases; limited resources for contact tracing across multiple high-risk settings (including GPs and hospitals) and lack of timely data on vaccine coverage in sub-groups of the population to guide public health action.

Prospective use of whole genome sequencing (WGS) detected a multi-country outbreak of Salmonella Enteritidis.

Since April 2015, whole genome sequencing (WGS) has been the routine test for Salmonella identification, surveillance and outbreak investigation at the national reference laboratory in England and Wales. In May 2015, an outbreak of Salmonella Enteritidis cases was detected using WGS data and investigated. UK cases were interviewed to obtain a food history and links between suppliers were mapped to produce a food chain network for chicken eggs. The association between the food chain network and the phylogeny was explored using a network comparison approach. Food and environmental samples were taken from premises linked to cases and tested for Salmonella. Within the outbreak single nucleotide polymorphism defined cluster, 136 cases were identified in the UK and 18 in Spain. One isolate from a food containing chicken eggs was within the outbreak cluster. There was a significant association between the chicken egg food chain of UK cases and phylogeny of outbreak isolates. This is the first published Salmonella outbreak to be prospectively detected using WGS. This outbreak in the UK was linked with contemporaneous cases in Spain by WGS. We conclude that UK and Spanish cases were exposed to a common source of Salmonella-contaminated chicken eggs.

What is the utility of using syndromic surveillance systems during large subnational infectious gastrointestinal disease outbreaks? An observational study using case studies from the past 5 years in England.

Syndromic surveillance systems in England have demonstrated utility in the early identification of seasonal gastrointestinal illness (GI) tracking its spatio-temporal distribution and enabling early public health action. There would be additional public health utility if syndromic surveillance systems could detect or track subnational infectious disease outbreaks. To investigate using syndromic surveillance for this purpose we retrospectively identified eight large GI outbreaks between 2009 and 2014 (four randomly and four purposively sampled). We then examined syndromic surveillance information prospectively collected by the Real-time Syndromic Surveillance team within Public Health England for evidence of possible outbreak-related changes. None of the outbreaks were identified contemporaneously and no alerts were made to relevant public health teams. Retrospectively, two of the outbreaks - which happened at similar times and in proximal geographical locations - demonstrated changes in the local trends of relevant syndromic indicators and exhibited a clustering of statistical alarms, but did not warrant alerting local health protection teams. Our suite of syndromic surveillance systems may be more suited to their original purposes than as means of detecting or monitoring localized, subnational GI outbreaks. This should, however, be considered in the context of this study's limitations; further prospective work is needed to fully explore the use of syndromic surveillance for this purpose. Provided geographical coverage is sufficient, syndromic surveillance systems could be able to provide reassurance of no or minor excess healthcare systems usage during localized GI incidents.

Retrospective cohort study of liver transplantation in the United Kingdom between 1994 and 2010: the impact of hepatitis C infection.

BACKGROUND: Liver transplantation is an important and established treatment option for chronic hepatitis C virus (HCV) related end-stage liver disease (HCV-related ESLD). This study describes trends in elective liver transplantation among persons with HCV-related ESLD. STUDY DESIGN: Retrospective cohort. METHODS: Analyses of United Kingdom (UK) Transplant Registry data for the period 1994 to 2010, with follow-up information extending to 2011. RESULTS: Annual registrations for liver transplantation increased linearly and alcoholic liver cirrhosis (2075, 24%) and HCV-related ESLD (1213, 14%) were the most common indications. HCV-related ESLD patients were mainly aged 40-49 years (32%) and 50-59 years (43%); males (76%); and of white ethnicity (74%). Overall, 75% (956/1213) received a liver transplant with a linear increase over the period (OR 1.11, 95% CI 1.08, 1.13). Pre transplant mortality was unchanged (adjusted OR 1.0, 95% CI 0.96, 1.05) and post-transplant mortality decreased in both HCV-related (adjusted OR 0.77, 95% CI 0.68, 0.88) and non-HCV-related ESLD (adjusted OR 0.82, 95% CI 0.75, 0.89) patients. CONCLUSION: The increase in demand for and receipt of liver transplants among persons with HCV-related ESLD requires coordinated efforts to increase not only organ donation, but investment in HCV prevention programmes and improved access to hepatitis C treatment services.

Large outbreak of verocytotoxin-producing Escherichia coli O157 infection in visitors to a petting farm in South East England, 2009.

In the summer of 2009, an outbreak of verocytotoxigenic Escherichia coli O157 (VTEC O157) was identified in visitors to a large petting farm in South East England. The peak attack rate was 6/1000 visitors, and highest in those aged <2 years (16/1000). We conducted a case-control study with associated microbiological investigations, on human, animal and environmental samples. We identified 93 cases; 65 primary, 13 secondary and 15 asymptomatic. Cases were more likely to have visited a specific barn, stayed for prolonged periods and be infrequent farm visitors. The causative organism was identified as VTEC O157 PT21/28 with the same VNTR profile as that isolated in faecal specimens from farm animals and the physical environment, mostly in the same barn. Contact with farm livestock, especially ruminants, should be urgently reviewed at the earliest suspicion of a farm-related VTEC O157 outbreak and appropriate risk management procedures implemented without delay.

A swimming pool-associated outbreak of cryptosporidiosis in Staffordshire, England, October to December 2007.

In October 2007 an increase in laboratory-confirmed cryptosporidiosis cases in Staffordshire, England prompted an outbreak investigation. Case ascertainment included interviewing suspected cases and contacts and obtaining faecal specimens from those with diarrhoea for laboratory identification. Over a three-month period we identified 57 cases of cryptosporidiosis (39 confirmed) distributed across 36 households. The majority of cases (69%) were younger than 20 years. The most plausible exposure was multiple swimming episodes (56% of cases) in 13 local public swimming pools. One large swimming pool was most frequently visited by swimmers and considered a significant contributor to transmission because of substandard filtration and maintenance systems. Control measures focused on inspecting and improving operating standards at swimming pools, hygiene information to swimmers, and early detection and exclusion of cases. The rapid case investigation described in this paper provided adequate information for the early detection and control of a typical seasonal swimming pool related cryptosporidiosis outbreak. Ensuring adequate filtration standards at public swimming pools particularly before the high use periods of late summer and autumn remains a priority.

Association between post-craniotomy Propionibacterium acnes infection and dural implants: a case-control study.

BACKGROUND: In 2011, 15 deep-seated Propionibacterium acnes infections were identified in patients following craniotomies in a hospital in the UK. AIM: To describe the outbreak and report findings from the investigation undertaken in order to identify the source and risk factors and inform control measures. METHODS: Data were obtained from hospital clinical records and included patient and surgical variables. Cases were defined as patients with microbiologically confirmed deep or organ space surgical site infection (SSI) caused by P. acnes following craniotomy undertaken in 2011. Four controls per case were randomly selected from patients who had a craniotomy in 2011 but who did not develop any SSI. The relationship between infection and putative exposures was examined using multivariate regression techniques. Infection prevention procedures and the theatre environment were reviewed to assess compliance with existing standards. FINDINGS: Fifteen cases and 65 controls were recruited. Odds of infection were higher for those who had a dural implant inserted during their operation [adjusted odds ratio (aOR): 14.6; 95% confidence interval (CI): 0.95-∞] and for those who had alcohol/Betadine®/chlorhexidine mix as a disinfectant (aOR: 7.9; 95% CI: 0.8-∞). Environmental investigations suggested that theatre ventilation systems delivered air exchange rates below the recommended standard. CONCLUSION: There was a positive association between using dural implants and P. acnes infection. Infection may have been facilitated by inefficient use of skin disinfectant and environmental factors. Recommendations included ongoing surveillance, the use of chlorhexidine skin disinfectant, ensuring adequate air exchanges and appropriate use of doors in theatre to minimize air turbulence.

Estimating the positive predictive value of opportunistic population testing for gonorrhoea as part of the English Chlamydia Screening Programme.

Advances in technology have raised the possibility of including gonorrhoea testing as part of chlamydia screening. In England this is recommended only where the positive predictive value (PPV) of the test is ≥90%. This study assessed the PPV for gonorrhoea testing using routine testing data. Routine data (including gonorrhoea testing) from the Greater Manchester Chlamydia Screening Programme (GMCSP) in 2009/2010, were used to estimate the PPV for gonorrhoea testing. Of those screened, 0.3% (59/18044) of men and 0.4% (174/41873) of women tested positive for gonorrhoea. The PPV was 82.3% in women and 73.6% in men, in those who also tested positive for chlamydia. For women and men testing negative for chlamydia the PPV for a positive gonorrhoea test was incalculable. The low PPV observed in most groups suggests that where population testing for gonorrhoea occurs there is a need for further confirmatory testing of positive results before treatment decisions are made. Clinicians should be aware of screening test result limitations in this context.