The impact of new national guidance for the public health management of enteric fever in England.

OBJECTIVES: New guidance was published in England in February 2012 to support the public health management of enteric fever and reduce the risks of secondary transmission. The new guidance was evaluated to assess: STUDY DESIGN: Quantitative and qualitative evaluation of the implementation of new public health guidance. METHODS: A qualitative review of all non-travel-related cases from February 2010 to January 2014 to compare the risk of secondary transmission before and after the guidance introduction; an audit of clearance sampling for each case and their contacts reported in London from February 2012-January 2015 to compare with a previous London audit; and an online user survey in November 2014. RESULTS: The proportions of non-travel cases reported before and after the introduction of the new guidance were similar, 6% in 2010-2012 compared to 7% in 2012-2014 (P = 0.33). There was a 32% reduction in the number of clearance samples required for cases and the estimated period of exclusion from work or school was reduced from 54 days to 16 days. Compliance in case clearance improved from 53% to 90% and contact screening compliance improved from 42% to 80%. The targeted screening of contacts led to a significantly higher positive yield (3.6% from 1.5%, P = 0.003). All symptomatic co-travellers presented to a healthcare professional, suggesting that screening could be restricted to those in risk groups for transmission. Feedback from users highlighted additional areas, such as management of large organised groups of co-travellers and those diagnosed abroad, which has informed the update of the national guidance. CONCLUSIONS: The new guidance has not led to an increase in secondary transmission of enteric fever in England and findings have been used to inform an update of the guidance. The new guidance also represents a reduced burden of investigation and thus a likely reduced cost to patients, healthcare professionals, laboratories and environmental health officers.

Public health management of Salmonella Typhi/Paratyphi case and contact screening: lessons from North London.

OBJECTIVES: To evaluate the public health management Salmonella enterica serovar Typhi (typhoid) and Salmonella enterica serovar Paratyphi (paratyphoid) cases and their contacts to assess the outcome of screening. STUDY DESIGN: Retrospective case note review. METHODS: 329 cases and 1153 contacts from North London over a four year period were reviewed. Structured questionnaires were developed to capture travel history, relationship between case/contact and the number, timing and documented results of faecal specimens. Evaluation of compliance with the clearance/screening schedule was examined and the positive yield of faecal samples for cases and contacts was calculated. RESULTS: 1% (3/329) of cases had a positive clearance sample; all were identified on their first faecal specimen. Of the 645 contacts who were screened, only 10 (1.5%), all of whom had travelled with the index case, were positive. Person-to-person transmission was only identified for two UK acquired cases, where possible carrier sources were identified outside the screening schedule. CONCLUSION: The lack of evidence of secondary transmission from acute cases, coupled with the low positive yield from clearance samples support the revision of the national guidance for the public health management of cases of enteric fever and their contacts.

A fatal case of Lassa fever in London, January 2009.

In January 2009, the eleventh [corrected] case of Lassa fever imported to the United Kingdom was diagnosed in London. Risk assessment of 328 healthcare contacts with potential direct exposure to Lassa virus - through contact with the case or exposure to bodily fluids - was undertaken. No contacts were assessed to be at high risk of infection and no secondary clinical cases identified.

Investigations and control measures following a case of inhalation anthrax in East London in a drum maker and drummer, October 2008.

The patient is believed to have acquired the infection from making animal hide drums. Environmental investigations identified one drum and two pieces of animal skins contaminated with anthrax spores.

Role of Food Handlers in Norovirus Outbreaks in London and South East England, 2013 to 2015.

Outbreaks caused by norovirus infection are common and occur throughout the year. Outbreaks can be related to food outlets either through a contaminated food source or an infected food handler. Both asymptomatic and symptomatic food handlers are potentially implicated in outbreaks, but evidence of transmission is limited. To understand potential food handler transmission in outbreak scenarios, epidemiological and microbiological data on possible and confirmed norovirus outbreaks reported in London and South East England in a 2-year period were reviewed. One hundred eighty-six outbreaks were associated with a food outlet or registered caterer in this period. These occurred throughout the year with peaks in quarter 1 of study years. A case series of 17 outbreaks investigated by the local field epidemiological service were evaluated further, representing more than 606 cases. In five outbreaks, symptomatic food handlers were tested and found positive for norovirus. In four outbreaks, symptomatic food handlers were not tested. Asymptomatic food handlers were tested in three outbreaks but positive for norovirus in one only. Environmental sampling did not identify the causative agent conclusively in any of the outbreaks included in this analysis. Food sampling identified norovirus in one outbreak. Recommendations from this study include for outbreak investigations to encourage testing of symptomatic food handlers and for food and environmental samples to be taken as soon as possible. In addition, sampling of asymptomatic food handlers should be considered when possible. However, in light of the complexity in conclusively identifying a source of infection, general measures to improve hand hygiene are recommended, with specific education among food handlers about the potential for foodborne pathogen transmission during asymptomatic infection, as well as reinforcing the importance of self-exclusion from food handling activities when symptomatic.

Guidelines for the public health management of typhoid and paratyphoid in England: practice guidelines from the National Typhoid and Paratyphoid Reference Group.

OBJECTIVES: The Typhoid and Paratyphoid Reference Group (TPRG) was convened by the Health Protection Agency (HPA) and the Chartered Institute of Environmental Health (CIEH) to revise guidelines for public health management of enteric fever. This paper presents the new guidelines for England and their rationale. METHODS: Methods include literature reviews including grey literature such as audit data and case studies; analysis of enhanced surveillance data from England, Wales and Northern Ireland; review of clearance and screening schedules in use in other non-endemic areas; and expert consensus. RESULTS: The evidence and principles underpinning the new guidance are summarised. Significant changes from previous guidance include: • Algorithms to guide risk assessment and management, based on risk group and travel history; • Outline of investigation of non-travel cases; • Simplified microbiological clearance schedules for cases and contacts; • Targeted co-traveller screening and a "warn and inform" approach for contacts; • Management of convalescent and chronic carriers. CONCLUSIONS: The guidelines were launched in February 2012. Feedback has been positive: the guidelines are reported to be clear, systematic, practical and risk-based. An evaluation of the guidelines is outlined and will add to the evidence base. There is potential for simplification and consistency between international guidelines.

Evaluation of the effectiveness and efficiency of the public health management of cases of infection due to Salmonella typhi/paratyphi in North East London.

OBJECTIVES: To evaluate the public health management of cases of Salmonella typhi/paratyphi in North East London in relation to national Public Health Laboratory Service (PHLS) guidelines and to determine the effectiveness and efficiency of current practice. STUDY DESIGN: A retrospective case-note review of laboratory-diagnosed cases of infection due to S. typhi/paratyphi in North East London in the 36 months from January 2002 to June 2004. RESULTS: Eighty-one cases were diagnosed with infection due to S. typhi/paratyphi during the study period. Sixty-seven cases (83%) were notified to the relevant local authority and 38 of these had at least the minimum number of follow-up samples recommended in national guidelines. A total of 251 contacts were screened with between one and six stool samples. One contact was identified who appeared to be a chronic carrier of S. typhi. The cost of identifying one person with a positive stool sample was estimated to be pounds sterling 3463 and the cost of detecting one probable chronic carrier was estimated at pounds sterling 17315. CONCLUSIONS: : There have been considerable difficulties in ensuring that case follow-up and contact screening is carried out according to national guidelines in North East London. Amongst those screened, the detection of excretors of pathogenic organisms was low. No chronic carriers were detected amongst the contacts of cases that acquired their infection abroad. Screening all such contacts is difficult to carry out and appears to be an inefficient use of resources.