Systematic national surveillance of outbreaks of infectious intestinal disease (IID) was introduced in England and Wales in 1992 to provide comprehensive information on causative organisms, sources or vehicles of infection and modes of transmission. We compared information from this system with that published in the peer-reviewed literature between 1 January 1992 and 31 January 2003 to assess the potential effect of publication bias on food-safety policy. During the study period 1763 foodborne outbreaks of IID were reported to national surveillance. Fifty-five were published in the peer-reviewed literature. The peer-reviewed literature overestimated the impacts of milk/milk products, miscellaneous foods (e.g. sandwiches) and desserts and underestimated those of poultry, fish and shellfish, red meat/meat products and eggs/egg products. Without systematic surveillance, knowledge of causative organisms, sources or vehicles of infection and modes of transmission, as gleaned from the peer-reviewed literature, would potentially distort food-safety policy.

Fresh produce is an important part of a healthy diet and is consumed in greater quantity in the United States than ever before. Consumption of cantaloupe has recently been associated with several large outbreaks of infections in North America, highlighting the need for a better understanding of practices and processes that may contribute to contamination. We reviewed all cantaloupe-associated outbreaks that were reported to the Centers for Disease Control and Prevention (CDC) and published in the literature. Twenty-three outbreaks occurred between 1984 and 2002; 1434 people became ill, 42 were hospitalized, and two died in these outbreaks. Aetiological agents in the outbreaks included five serotypes of Salmonella enterica, Campylobacter jejuni, Escherichia coli O157:H7, and norovirus. We reviewed processes contributing to cantaloupe contamination, conditions affecting survival and growth of bacterial pathogens on melons, and potential methods for sanitization. For maximum safety, industry, federal, and international partners must collaborate to ensure that appropriate interventions are in place to minimize the risk of contamination and prevent the growth of pathogens during cantaloupe production, processing, storage, and preparation.

Routine surveillance data underestimate incidence of foodborne gastrointestinal (FGI) illness and provide little information on illness related to travel. We analysed data from the Welsh Health Survey to estimate population incidence, and to examine risk factors for FGI and factors associated with consulting a doctor. Reported frequency of any FGI in the 3 months before interview was 20·0% [95% confidence interval (CI) 19·5–20·4; equivalent to 0·8 episodes per person-year], and for travel-related FGI was 1·6% (95% CI 1·5–1·8). In the final model, sex, age group, marital status, self-reported health, long-term illness, smoking and alcohol consumption were all independent predictors of FGI. People who consulted a doctor were likely to be older, in poorer health, taking regular medication, or to report mental illness. FGI is common but risk factors for illness and consultation differ and impressions of the epidemiology of the disease based on surveillance data are therefore distorted.

The objectives of this study were to characterize faeco-orally transmitted parasitic diseases and to identify the factors associated with these diseases, with emphasis on environmental factors, in children ranging from 1 up to 5 years old residing in substandard settlement areas. A population-based cross-sectional epidemiological design was used in a non-random selection of 29 out of the 78 substandard settlement areas in the municipality of Juiz de Fora, Brazil. A sample of 753 children were assessed from the target population consisting of all children of the appropriate age range residing in the selected areas. Data were collected by means of domiciliary interviews with their mothers or with the person responsible for them. The Hoffmann–Pons–Janer method was used in the parasitological examination of faeces. Binary logistic regression models were used to identify the factors associated with the diseases. A total of 319 sample children presented faeco-orally transmitted parasitic diseases. The factors associated with these parasitic diseases included the children's age, family income, number of dwellers in the domicile, consumption of water from shallow wells, consumption of water from natural sources, absence of covered domiciliary water reservoirs, and the presence of sewage flowing in the street.

We obtained a list of all reported cases of Escherichia coli O157 in Alberta during the 2000–2002 period, and using scan statistics we identified yearly temporal and spatial clusters of reported cases of E. coli O157 during the summer and in southern Alberta. However, the location of the spatial cluster in the south was variable among years. The impact of using both outbreak and sporadic data or only sporadic data on the identification of spatial and temporal clusters was small when analysing individual years, but the difference between spatial clusters was pronounced when scanning the entire study period. We also identified space-time clusters that incorporated known outbreaks, and clusters that were suggestive of undetected outbreaks that we attempted to validate with molecular data. Our results suggest that scan statistics, based on a space-time permutation model, may have a role in outbreak investigation and surveillance programmes by identifying previously undetected outbreaks.

Over the past years Shiga-like toxin-producing Escherichia coli (STEC) O157:H7 emerged as an important cause of severe gastrointestinal illnesses and haemolytic–uraemic syndrome (HUS) with up to 10% of children infected with STEC developing HUS. We conducted a geographical ecological study using the district as the statistical unit. For each district, we estimated the incidence of HUS among children <15 years for the period 1996–2001 from national HUS surveillance data and data obtained on cattle density. We used multivariate Poisson regression to quantify the relation, adjusted for covariates, between paediatric HUS incidence and exposure to cattle. In univariate analysis, a positive association was observed between several cattle-density indicators and HUS incidence. In multivariate analysis, HUS paediatric incidence was associated with dairy cattle density and the ratio of calves to children <15 years (P<0·001). Our findings are consistent with previous studies in other countries and support the recommendation to limit exposure of children to dairy cattle and manure to reduce the risk of STEC infection.

This study investigates a sorbitol-fermenting enterohaemorrhagic Escherichia coli (SF EHEC) O157 infection in a farmer's family in the Austrian province of Salzburg. The investigation commenced after a 10-month-old boy was admitted to hospital with the clinical diagnosis of a haemolytic–uraemic syndrome (HUS) and his stool specimen grew SF EHEC O157:H−. In a subsequent environmental survey, a stool specimen of the 2-year-old brother and faecal samples of two cattle from the family's farm were also found to be positive for SF EHEC O157:H−. All four isolates had indistinguishable phenotypic and molecular characteristics and were identical to the first strain detected in Bavaria in 1988. Despite identical isolates being demonstrated in Bavaria after 1988, and until this report, increased surveillance in neighbouring Austria had not found this organism. We propose that the strain may have recently spread from Bavaria to Austria. Although SF EHEC O157:H− strains are still rare, they may represent a considerable health threat as they can spread from farm animals to humans and between humans.

In September 2000, haemolytic uraemic syndrome (HUS) was diagnosed in a 10-month-old child with a prodromal history of vomiting and diarrhoea (non-bloody). Investigation revealed that a self-limiting gastrointestinal illness (mean duration 48 h) had occurred among immediate and extended family in the 2 weeks prior to the child's admission. The epidemiology of the illness suggested person-to-person spread. Five children (close family contacts) had E. coli O26 verocytotoxin (VT1 and VT2) isolated from stools. Stool culture and serology from the index case were negative for shiga toxin-producing E. coli (STEC) organisms. Control measures in accordance with the Public Health Laboratory Service (PHLS), verocytotoxogenic organisms (VTEC) guidelines were applied to prevent further spread among the extended family and contacts. Despite detailed food and environmental exposure histories, the source of the illness was not identified. This incident highlights the importance of investigation of cases of post-diarrhoeal HUS, for potential shiga toxin E. coli aetiology.

This study investigates the distribution of pulsed-field gel electrophoresis (PFGE) profiles within Salmonella enterica serotype Enteritidis phage type (PT) 4 and S. Typhimurium definitive phage type (DT) 104, from cases of human infection in nine European countries from 2000 to 2004. Isolates were subtyped using standardized methods and gel images submitted by each participating country to the coordinating centre (Health Protection Agency Centre for Infections, London, UK), where they were entered into a central database, developed within BioNumerics software, and designated using an agreed nomenclature. S. Enteritidis PT4 (n=3637) was differentiated into 38 different profiles. Simpson's index of diversity (D) of profiles ranged from 0·2 to 0·4. Profile SENTXB.0001 represented at least 80% of all profiles in each country. S. Typhimurium DT104 (n=1202) was differentiated into 28 different profile types. Simpson's D was at least 0·6 in all countries except in Austria and Italy. In both these countries over 74% of S. Typhimurium DT104 profiles were STYMXB.0013. Profile STYMXB.0061, was predominant in Denmark, Spain, Finland and England & Wales where it represented between 36% and 45% of profiles. Profile STYMXB.0001 represented nearly half of all profiles in Scotland and 23% in England & Wales. PFGE is proving useful for further discrimination within S. Enteritidis PT4 and S. Typhimurium DT104. Ascertainment of international outbreaks involving common serotypes and phage types may be increased by the timely pooling of PFGE profiles within a central database readily accessible to all participating countries.

In summer 2004, an outbreak caused by Salmonella enterica serovar Enteritidis phage type 13 (S. Enteritidis PT13) was recorded in the Czech Republic. As well being a relatively rare phage type the strain was also ampicillin resistant. Outbreak (n=39) and pre-outbreak isolates (n=13) were characterized by pulsed-field gel electrophoresis (PFGE), β-lactamase gene polymerase chain reaction and plasmid profile. The majority of outbreak isolates (n=37) were identical in XbaI PFGE profile, and two other outbreak isolates each differed from this profile by one or two fragments respectively. The pre-outbreak isolates were uniform in PFGE profile but distinct from the outbreak strain. Ampicillin resistance was confirmed to be encoded by the blaTEM gene located on the TnA transposon. This gene was readily transferable to a S. Enteritidis recipient strain and was associated with the transfer of a 200-kb plasmid. Our results indicate that all S. Enteritidis PT13 tested from 2004 belonged to a single outbreak strain which prior to 2004 had not been recognized in the Czech Republic.

From 2000 to 2001, nine strains of Salmonella enterica belonging to the new serotype Keurmassar have been isolated from human and poultry samples at the Senegalese National Salmonella and Shigella Reference Laboratory at the Pasteur Institute, in Dakar. All strains carried virulence factors including Salmonella Pathogenicity Islands (SPI)-1, -2, -3 and -5 encoded genes. Strains did not harbour virulence plasmid. Ribotyping analysis revealed a single clone identical to Salmonella Decatur isolated in Zimbabwe. These data suggest that strains are closely related, and may have been spread clonally. In this new serotype, insertion sequence IS200 is not present.

We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17·3, 95% CI 2·4–160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.

Listeria monocytogenes is an important pathogen which causes an infection called listeriosis. Because of the high mortality rate (~30%) associated with listeriosis, and the widespread nature of the organism, it is a major concern for food and water microbiologists since it has been isolated from various types of foods, including seafood, as well as from the aqueous environment. To investigate the prevalence of this pathogen in the Aqaba Gulf (12 sites), Suez Gulf (14 sites) and Red Sea (14 sites), 200 water samples (collected during five sampling cruises in 2004), 40 fresh fish samples and 15 shellfish samples were analysed using the enrichment procedure and selective agar medium. All water samples were also examined for the presence Listeria innocua which was the most common of the Listeria spp. isolated, followed by L. monocytogenes, with a low incidence of the other species. During the whole year, the percentage of Listeria spp. and L. monocytogenes in 200 water samples was 20·5% (41 samples) and 13% (26 samples) respectively. In fresh fish (40 samples) it was 37% (15 samples) and 17·3% (7 samples) and in shellfish (15 samples) 53% (8 samples) and 33% (5 samples) respectively. In water samples, there was an association between the faecal contamination parameters and the presence of the pathogen; however, water salinity, temperature, dissolved oxygen and pH did not influence the occurrence of this bacterium. These results may help in the water-quality evaluation of the coastal environments of these regions.

The subtypes of Campylobacter isolates from human infections in two Danish counties were compared to isolates from retail food samples and faecal samples from chickens, pigs and cattle. During a 1-year period, 1285 Campylobacter isolates from these sources were typed by two methods: ‘Penner’ heat-stable serotyping and automated ribotyping (RiboPrinting). C. jejuni was the dominating species, but C. coli was more prevalent among food and chicken isolates (16%) compared to human isolates (4%). In total, 356 different combined sero-ribotypes (subtypes) were found. A large subtype overlap was seen between human isolates and isolates from food (66%), chickens (59%) and cattle (83%). This was verified by PFGE typing of 212 isolates representing selected subtypes. All frequent (n>3) subtypes found in food were also present in humans. Sixty-one per cent of the isolates from domestically acquired infections had subtypes that were also found in food as opposed to 31% of travel-associated infections. The results showed differences in the various Campylobacter populations, e.g. the Danish population as reflected in the domestically acquired infections and the Danish-produced food was more uniform than the isolates originating from outside the country. The study shows that most C. jejuni subtypes found in poultry food samples, broiler chickens, and cattle were represented in the domestically acquired cases, indicating that C. jejuni from these reservoirs are likely sources of human infections in Denmark.

In order to identify subtyping methods able to contribute to the surveillance or investigation of Australian Campylobacter infection, six genotypic and three phenotypic subtyping methods were evaluated on a collection of 84 clinical isolates collected over a 30-month period from one region in Australia. The aim was to compare the logistics of various subtyping methods and examine their ability to assist in finding outbreaks or common sources of sporadic infection. The genotypic subtyping methods used were sequencing of the short variable region of the flaA gene, two methods using restriction fragment length polymorphism (RFLP) of the flaA gene using either DdeI or EcoRI with PstI, automated ribotyping, pulsed field gel electrophoresis and multilocus sequence typing. The phenotypic methods employed included Laboratory of Enteric Pathogens serotyping, Lior biotyping and antibiotic resistotyping. The level of agreement between subtyping results was determined. Phenotypic methods showed little agreement whereas genotypic typing methods showed a high level of agreement. Using the premise that five of the six genotypic typing methods were in agreement 15 genotypic groupings were identified. Sequencing of the short variable region of the flaA gene, RFLP of the flaA gene or automated ribotyping in conjunction with multilocus sequence typing best identified genotypic groupings. An alternative combination of RFLP of the flaA gene followed by ribotyping was equally satisfactory. RFLP of the flaA gene appeared to be suitable as a preliminary typing method based on ease of operation, equipment availability and cost.

Vibrio parahaemolyticus and Vibrio vulnificus were isolated from faecal samples of wild aquatic birds in winter. Although V. parahaemolyticus and V. vulnificus were present in low numbers in seawater in the area where the faecal samples of the birds were collected, the pathogens were isolated from the faeces of the birds. This study demonstrates that wild aquatic birds are a vehicle for V. parahaemolyticus and V. vulnificus to survive in winter.

Severe acute respiratory syndrome (SARS) is a newly emerged infectious disease with a high case-fatality rate and devastating socio-economic impact. In this report we summarized the results from an epidemiological investigation of a SARS outbreak in a hospital in Tianjin, between April and May 2003. We collected epidemiological and clinical data on 111 suspect and probable cases of SARS associated with the outbreak. Transmission chain and outbreak clusters were investigated. The outbreak was single sourced and had eight clusters. All SARS cases in the hospital were traced to a single patient who directly infected 33 people. The patients ranged from 16 to 82 years of age (mean age 38·5 years); 38·7% were men. The overall case fatality in the SARS outbreak was 11·7% (13/111). The outbreak lasted around 4 weeks after the index case was identified. SARS is a highly contagious condition associated with substantial case fatality; an outbreak can result from one patient in a relatively short period. However, stringent public health measures seemed to be effective in breaking the disease transmission chain.

Both influenza and respiratory syncytial virus (RSV) cause epidemics of respiratory illness of variable severity during the winter season. Influenza in particular has been blamed for hospital winter bed pressures, although it is thought that RSV may also play a role. Human metapneumovirus (hMPV) is a new respiratory virus reported to be important in children; only a limited number of studies are available for adult populations. We aimed to determine initially the burden of virologically confirmed infections, i.e. influenza, RSV and hMPV using polymerase chain reaction (PCR) technology and, in addition, to assess the feasibility of this approach as a surveillance tool for these respiratory viruses. Adult patients admitted to hospital in the previous 24 hours with onset of acute respiratory symptoms in the last 14 days were asked to participate. Informed written consent was obtained and nose and throat swabs taken. Multiplex PCR for influenza A (H1N1 and H3N2), influenza B and RSV A and B were carried out together with a separate PCR for hMPV. A total of 219 patients in 2001–2002 and 216 in 2002–2003 were tested and the combined results for both seasons were: 8 positive for influenza A/H1N1, 14 for influenza A/H3N2, 2 for influenza B, 14 for RSV A and 6 for RSV B. Most patients (261/435) were >65 years and most positives (30/44) were found within this age group. A number of patients aged >65 years who were positive for influenza (12/15) reported having had vaccine. In total, 373 samples were tested for hMPV and 20 were found positive across all age groups except the 45–54 years age group. As influenza activity was low during the study period the impact of infection on admissions could not be assessed. Nevertheless the viruses studied accounted for 15% of hospital admissions for respiratory infection. Most patients were aged >65 years, as expected. In the two years studied RSV and hMPV were each responsible for as many hospitalized cases of respiratory infection as influenza. Influenza infection must be considered even in those who give a history of vaccination. The molecular methods used in this study showed that surveillance of these respiratory viruses can be conducted and may help in the management of patients.

We report an outbreak of hepatitis A that occurred in the city of Bari (Apulian region) in June 2002. Overall, 26 cases were observed over a 4-week period. These were traced back to the index case, a food handler who prepared various food products for sale over the counter at a store in the district (OR 5·36, CI 95% 1·58–19·25). Laboratory investigations confirmed that the outbreak was due to a point source and identified a new genotype IB variant. There is a possible indication for administration of hepatitis A vaccine to food handlers, although further evidence of an acceptable cost–benefit ratio needs to be ascertained.

To investigate risk factors during a community outbreak of hepatitis A we carried out a case- control study of 35 cases and 49 matched controls using an interviewer-administered questionnaire on clinical history, travel, household details including domestic toilet facilities, infectious contacts, and food history. Of 99 cases notified in the city during the outbreak year, 50 (51%) were young adults age 15–34 years. Hepatitis A infection was independently associated with household contact with a case (P=0·0005), and sharing a household with children in primary school (OR 3·4, 95% CI 1·2–9·5, P=0·008) with risk increasing with number of primary-school pupils in the household (χ2 for linear trend 6·47, P=0·01). We concluded that in a population with a low prevalence of hepatitis A, adults who live in the same household as primary-school-age children are at increased risk of acquiring the infection during community outbreaks.