Sentinel laboratory surveillance of hepatitis C antibody testing in England: understanding the epidemiology of HCV infection.

This paper describes sentinel laboratory surveillance of hepatitis C antibody testing in England. Demographic and test result data were supplemented by follow-up questionnaires sent to the requesting clinician. Between October 2002 and September 2003 almost 75000 anti-HCV tests were performed in eight sentinel centres. More males were tested than females and over half of those tested were aged 25-44 years. Overall 5.7% (3333/58144, range 2.8-7.7%) individuals tested positive. Follow-up questionnaire data showed that 82% (1043/1277) of the positives had injecting drug use reported as the main risk exposure. The majority of negative individuals were undergoing routine screening as recommended for specific patient groups. Most individuals were asymptomatic. Antibody prevalence was estimated to be 34% in current injecting drug users and 42% in former injectors. Comparing positives to routine national surveillance suggests that only 53% (1782/3333) of diagnosed cases were reported. Sentinel laboratory data can provide valuable supplementary data to national surveillance.

National symptom surveillance using calls to a telephone health advice service--United Kingdom, December 2001-February 2003.

INTRODUCTION: Recent terrorist activity has highlighted the need to improve surveillance systems for the early detection of chemical or biologic attacks. A new national surveillance system in the United Kingdom (UK) examines symptoms reported to NHS Direct, a telephone health advice service. OBJECTIVES: The aim of the surveillance system is to identify an increase in symptoms indicative of early stages of illness caused either by a deliberate release of a biologic or chemical agent or by common infections. METHODS: Data relating to 10 key syndromes (primarily respiratory and gastrointestinal) are received electronically from 23 call centers covering England and Wales. Data are analyzed daily and statistically significant excesses, termed exceedances, in calls are automatically highlighted and assessed by a multidisciplinary team. RESULTS: During December 2001-February 2003, a total of 1,811 exceedances occurred, of which 126 required further investigation and 16 resulted in alerts to local or national health-protection teams. Examples of these investigations are described. CONCLUSION: Surveillance of call-center data has detected substantial levels of specific syndromes at both national and regional levels. Although no deliberate release of a biologic or chemical agent has been detected thus far by this or any other surveillance system in the UK, the NHS Direct surveillance system continues to be refined.

What can analysis of calls to NHS direct tell us about the epidemiology of gastrointestinal infections in the community?

OBJECTIVES: Most gastrointestinal (GI) illness within the UK goes undetected by routine surveillance. A national telephone helpline for health advice (NHS Direct) offers a new source of data on GI infection. We aim to describe NHS Direct calls suggestive of GI infection and the outcome of these calls. METHODS: Details of over 150000 telephone calls were collected from NHS Direct over a 6-month period. Calls about 'diarrhoea', 'vomiting' or 'food poisoning' were defined as GI calls and described according to the age of the patient and call outcome. RESULTS: Gastrointestinal calls accounted for 10.3% of total calls ('diarrhoea'=4.9%, 'vomiting'=5.1%). GI calls as a proportion of total calls were significantly high in children under 1 year (23.5%) and aged 1-4 years (21.5%). Call outcomes which resulted in further NHS care being recommended accounted for 72.3% of total calls and 54.5% of GI calls. CONCLUSIONS: A high proportion of NHS Direct calls were about GI symptoms especially for children under 5 years. When compared with all NHS Direct calls, GI calls were less likely to result in further NHS care being recommended. Analysis of NHS Direct calls provides further insight into GI infection in the community.

Use of NHS Direct calls for surveillance of influenza--a second year's experience.

A second year's call data to NHS Direct are presented to evaluate their usefulness for influenza surveillance. During the winter of 2000-01, age-group-specific data relating to the 'cold/flu' algorithm were collected from six NHS Direct sites (population coverage: 16 million). The total number of calls was collected from all 23 NHS Direct sites on a daily basis. Despite the winter of 2000-01 having been a season of low activity for influenza in the United Kingdom, NHS Direct data demonstrated a peak in the 'cold/flu' calls as a proportion of the total calls (3.1% [672 'cold/flu' calls] during week 06/01). This coincided with the peak recorded by routine influenza surveillance systems. There was also an earlier peak in the proportion of 'cold/flu' calls (3.3% during weeks 52/00 [789 'cold/flu' calls] and 01/01 [749 'cold/flu' calls]) which may have been due to other respiratory infections, the lack of specificity of the definition of NHS Direct 'cold/flu' calls and an increase in 'out-of-hours' calls to NHS Direct at the time. Despite limitations, the timeliness of NHS Direct data, the total population coverage of the service and the ability to provide local information on 'cold/flu' calls make the call data suitable for further surveillance during the winter of 2001-02. It is hoped that as NHS Direct reaches a 'steady state' in terms of population coverage and uniformity of clinical support systems, it will be possible to begin to construct 'baselines' for the respiratory disease related call data.

Hospital-acquired listeriosis.

We report four cases of listeriosis that occurred over a two-month period in north east England. Due to the apparent nosocomial acquisition of infection and the clustering of cases in time and place, extended epidemiological investigation was performed and the outbreak was traced to a caterer who was providing sandwiches for hospital shops. We discuss the difficulties in preventing food-borne listeriosis in the hospital setting.

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.

Can calls to NHS Direct be used for syndromic surveillance?

This study assessed whether NHS Direct could be a useful source of surveillance data for communicable diseases, using influenza as a pilot condition. Data on the weekly total number of calls and the number from people reporting influenza-like symptoms to three pilot NHS Direct sites were collected between November 1999 and March 2000. NHS Direct data were compared with routinely available influenza surveillance data. The NHS Direct call rate peaked at 331 per 100,000 population in week 52 of 1999. The percentage of calls for 'influenza-like illness' (one site) peaked at 15% during week 51. Information about weekly call numbers to NHS Direct could be produced in a timely way. It was not clear whether the observed peak in calls reflected a true increase in influenza or whether it was the result of an increase in calls over the Christmas/Millennium holiday period due to more difficulty in accessing other services. The ability to assess the proportion of calls made directly by, or on behalf of, each age group will be of vital importance in interpreting seasonal respiratory disease.

Common source outbreak of salmonellosis in a food factory.

Seventy-three employees at a food processing factory employing 2700 staff reported vomiting, diarrhoea, or abdominal pain between 30 July and 3 August 1997. Salmonella enteritidis phage type (PT) 4 was isolated from 47 symptomatic cases and five asymptomatic canteen staff. The epidemic curve suggested a point exposure to a common source: 60% of cases reported illness on 31 July. An uncooked dessert containing raw shell eggs was identified as a possible vehicle of infection. Caterers are reminded that pasteurised egg should be substituted for shell egg in dishes that are eaten raw or only lightly cooked.

Lessons from patient notification exercises following the identification of hepatitis B e antigen positive surgeons in an English health region.

The results of hepatitis B virus (HBV) serology from notification exercises conducted in cohorts of patients exposed to three surgeons positive for hepatitis B e antigen (HBeAg) identified in one English health region in 1994 and 1995 were reviewed. Of 777 patients notified, serology results at six months or more after exposure were available for 514 individuals who had not received post exposure prophylaxis. In one case DNA analysis confirmed transmission of HBV from surgeon to patient. Pre-existing natural immunity to HBV was found in a further 19 patients, none of whom had evidence of recent infection, and in 13 patients (classified as cases of undetermined origin) transmission during surgery could not be excluded. The overall estimated transmission rate was 0.2% for confirmed cases (95% confidence interval (CI) 0.004-1.1) and 2.7% (95% CI 1.5-4.5) if cases of undetermined origin were included. The management of recall exercises should consider the risks of the operative procedures performed and the time that has elapsed since exposure.

A survey of the incidence and care of postoperative wound infections in the community.

The incidence of postoperative wound infection after clean surgery in the four weeks following early discharge from hospital and its effect on community medical services have been studied prospectively. The wound infection rate as assessed by 118/155 patients who responded to a postoperative questionnaire was 9%; half of the wound problems presented after discharge. Postoperative wound infection increased the time spent by general practitioners per patient twofold, and that of practice/district nurses > or = fivefold.

Meningitis: public health issues.

This paper describes a case-note review of 25 cases of meningococcal disease which occurred in the six months following distribution of pre-admission antibiotic treatment packs and prophylaxis advice packs. The data showed that while these interventions had improved some aspects of public health, and management of cases and their contacts, further action was needed

Pseudomonas aeruginosa wound infection associated with a nursing home's whirlpool bath.

Whirlpool baths are fitted with hydrojet circulation and/or air induction bubble systems. Water in a whirlpool bath, unlike a spa pool, is not filtered or chemically treated but the bath is drained and cleaned between each bather. This is, we believe, the first report of Pseudomonas aeruginosa wound infection associated with the use of a whirlpool bath in a nursing home. Microbiologically confirmed infections with P. aeruginosa of identical antibiotic sensitivity patterns arose in one week in wounds of four of 24 residents who used a whirlpool bath from which P. aeruginosa was also isolated. P. aeruginosa was not isolated from the wounds of a further seven residents who did not use the whirlpool bath. The incident control team advised that use of the whirlpool bath should be restricted to continent residents with intact skin, and that the bath should be cleaned with a degreasing agent and disinfected with hypochlorite between use by individual residents. The hazard of infection posed by whirlpool baths, particularly in nursing homes, needs to be assessed. National guidance for their cleaning, maintenance, and disinfection is required.

Whirlpool baths in nursing homes: use, maintenance, and contamination with Pseudomonas aeruginosa.

Transmission of Pseudomonas aeruginosa wound infection was associated with the use of a whirlpool bath in a nursing home. The nursing home inspection unit asked for guidance on whirlpool baths in nursing homes and advice for proprietors about their use, cleaning, disinfection, and maintenance. Seventeen whirlpool baths in 16 nursing homes in two health districts were examined for the presence of P. aeruginosa. A survey was made of the use made of whirlpool baths, methods used to clean and disinfect them, and the occurrence of P. aeruginosa wound infection in users. P. aeruginosa were found in large numbers in water samples from all whirlpool baths after agitation. Only one of the 253 residents who used whirlpool baths was known to have a P. aeruginosa wound infection. The local nursing home inspection unit was advised that whirlpool baths could continue to be used in nursing homes but only by continent residents with intact skin. The bath should be cleaned and disinfected, preferably with hypochlorite, after each use; the bath should be more thoroughly cleaned and disinfected daily and the bath should be fully serviced at least once a year. Suspected or confirmed cases of P. aeruginosa infection in residents of nursing homes should be reported to the consultant in communicable disease control. The prevalence of known infection with P. aeruginosa was low in the residents of the nursing homes, but the unguided and unregulated use of whirlpool baths in nursing homes may present an infection hazard to residents who use the bath and to hospitals that admit residents from such nursing homes.(ABSTRACT TRUNCATED AT 250 WORDS)