Outbreak of Escherichia coli O157 infection associated with a music festival

Glastonbury Festival: Medical Care at the World's Largest Greenfield Music Festival

INTRODUCTION

Music festivals have become an increasingly popular form of mass-gathering event, drawing an increasing number of attendees across the world each year. While festivals exist to provide guests with an enjoyable experience, there have been instances of serious illness, injury, and in some cases death. Large crowds, prolonged exposure to loud music, and high rates of drug and alcohol consumption can pose a dangerous environment for guests as well as those looking after them.

METHODS

A retrospective review of electronic patient records (EPRs) at the 2022 Glastonbury Festival was undertaken. All patients who attended medical services on-site during the festival and immediately after were included. Patient demographics, diagnosis, treatment received, and discharge destination were obtained and analyzed.

RESULTS

A total of 2,828 patients received on-site medical care. The patient presentation rate (PPR) was 13.47 and the transport-to-hospital rate (TTHR) was 0.30 per 1,000 guests. The most common diagnoses were joint injuries, gastrointestinal conditions, and blisters. Only 164 patients (5.48%) were diagnosed as being intoxicated. Overall, 552 patients (19.52%) were prescribed a medication to take away and 268 (9.48%) had a dressing for a minor wound. One patient (0.04%) underwent a general anesthetic and no patients required cardiopulmonary resuscitation. Most patients were discharged back to the festival site (2,563; 90.66%).

DISCUSSION

Minor conditions were responsible for many presentations and most patients only required mild or non-invasive interventions, after which they could be safely discharged back to the festival. Older adults were diagnosed with a different frequency of conditions compared to the overall study population, something not reported previously. Intoxicated patients only accounted for a very small amount of the medical workload.

Survival of Enterohemorrhagic Escherichia coli O104:H4 Strain C227/11Φcu in Agricultural Soils Depends on rpoS and Environmental Factors

The consumption of contaminated fresh produce caused outbreaks of enterohemorrhagic (EHEC) Escherichia coli. Agricultural soil might be a reservoir for EHEC strains and represent a contamination source for edible plants. Furthermore, the application of manure as fertilizer is an important contamination route. Thus, the German fertilizer ordinance prohibits the use of manure 12 weeks before crop harvest to avoid pathogen transmission into the food chain. In this study, the survival of E. coli O104:H4 strain C227/11Φcu in soil microenvironments with either diluvial sand or alluvial loam at two temperatures was investigated for more than 12 weeks. It was analyzed whether the addition of cattle manure extends EHEC survival in these microenvironments. The experiments were additionally performed with isogenic ΔrpoS and ΔfliC deletion mutants of C227/11Φcu. The survival of C227/11Φcu was highest at 4 °C, whereas the soil type had a minor influence. The addition of cattle manure increased the survival at 22 °C. Deletion of rpoS significantly decreased the survival period under all cultivation conditions, whereas fliC deletion did not have any influence. The results of our study demonstrate that EHEC C227/11Φcu is able to survive for more than 12 weeks in soil microenvironments and that RpoS is an important determinant for survival.

An outbreak of Shiga toxin-producing Escherichia coli O157:H7 linked to a mud-based obstacle course, England, August 2018

In August 2018, Public Health England (PHE) was made aware of five probable cases of Shiga toxin-producing Escherichia coli (STEC) O157:H7 among individuals reporting participation in a mud-based obstacle race. An additional four cases, identified via routine whole-genome sequencing, were subsequently linked to the same event. Two of the nine cases were due to secondary household transmission. Despite an agreement between the event organizers and the local authority, to ensure that all livestock were removed from the site 28 days before the event, sheep were observed grazing on some of the routes taken by the runners 2 days prior to the race taking place. A retrospective review of incidents reported to PHE between 2015 and 2018 identified 41 cases of gastroenteritis associated with muddy assault course events. Of these, 25 cases were due to infection with STEC O157:H7, of which all but one were associated with outbreaks. Due to the environment in which such events take place, it is impossible to entirely remove the risk of exposure to potentially pathogenic zoonoses. However, race organizers should ensure that livestock are removed from the course 28 days before the event. They should also ensure that participants are made aware of the risk of contracting gastrointestinal disease from the environment, and to stress the importance of hand hygiene post-event and the risk of secondary transmission, particularly to children who are at risk of developing haemolytic uraemic syndrome.

Regional differences in presence of Shiga toxin-producing Escherichia coli virulence-associated genes in the environment in the North West and East Anglian regions of England

Shiga toxin-producing Escherichia coli is carried in the intestine of ruminant animals, and outbreaks have occurred after contact with ruminant animals or their environment. The presence of STEC virulence genes in the environment was investigated along recreational walking paths in the North West and East Anglia regions of England. In all, 720 boot sock samples from walkers' shoes were collected between April 2013 and July 2014. Multiplex PCR was used to detect E. coli based on the amplification of the uidA gene and investigate STEC-associated virulence genes eaeA, stx1 and stx2. The eaeA virulence gene was detected in 45·5% of the samples, where stx1 and/or stx2 was detected in 12·4% of samples. There was a difference between the two regions sampled, with the North West exhibiting a higher proportion of positive boot socks for stx compared to East Anglia. In univariate analysis, ground conditions, river flow and temperature were associated with positive boot socks. The detection of stx genes in the soil samples suggests that STEC is present in the English countryside and individuals may be at risk for infection after outdoor activities even if there is no direct contact with animals. SIGNIFICANCE AND IMPACT OF THE STUDY: Several outbreaks within the UK have highlighted the danger of contracting Shiga toxin-producing Escherichia coli from contact with areas recently vacated by livestock. This is more likely to occur for STEC infections compared to other zoonotic bacteria given the low infectious dose required. While studies have determined the prevalence of STEC within farms and petting zoos, determining the risk to individuals enjoying recreational outdoor activities that occur near where livestock may be present is less researched. This study describes the prevalence with which stx genes, indicative of STEC bacteria, were found in the environment in the English countryside.

Infection from Outdoor Sporting Events-More Risk than We Think?

Competitive sports that involve extensive contact with mud are commonly held events and growing in popularity. However, the natural environment contributes to infection risks, and these events have been implicated in multiple infectious disease outbreaks. Soils and mud contain rich microbial communities and can include pathogens (including viruses, bacteria, and parasites), thereby offering risk of infection; there is also a risk of disease due to shedding, by participants, of pathogens directly into the environment. These disease risks are ubiquitous and are present in the most developed countries, as well as elsewhere. Prevention of the further spread of mud sport-related infections through secondary infections to non-participant community members is of critical importance. We recommend shifts in practice and policy, such as site condition monitoring, improved messaging with regards to infections risk, and implementation of pre- and post-event wash stations to reduce these risks.

Outbreak of diarrhoeal illness in participants in an obstacle adventure race, Alpes-Maritimes, France, June 2015

An acute gastroenteritis (AG) outbreak occurred among participants in an obstacle race in France in the summer of 2015. An investigation in two phases was conducted to identify the source of infection and document the extent of the outbreak. First, a message on a social media website asked racers to report any symptoms by email to the Regional Health Agency of Provence-Alpes-Côte d'Azur. Second, a retrospective cross-sectional study was conducted through an interactive questionnaire for all participants, followed by an analytical study of potential risks factors. Of 8,229 persons registered, 1,264 adults reported AG resolved within 48 hours. Of adults who reported AG, 866 met the case definition. Age group, departure time and ingestion of mud were associated with AG. Twenty stool specimens tested negative for bacteria. All four stool samples tested for viruses were positive for norovirus genogroup I and genotype 2. No indicator bacteria for faecal contamination were found in drinking water but muddy water of ponds tested positive. The outbreak was possibly caused by human-to-human transmission of a norovirus introduced by one or more persons and transmitted through contaminated mud. Risks related to similar races should be assessed and recommendations be proposed to raise awareness among health authorities and organisers.

Communicable diseases as health risks at mass gatherings other than Hajj: what is the evidence?

Mass gatherings are characterized by the concentration of people temporally and spatially, and may lead to the emergence of infectious diseases due to enhanced transmission between attendees. This is well-demonstrated in the context of the Hajj and Umrah pilgrimages in Saudi Arabia. The goal of this review was to present the available evidence on outbreaks associated with a variety of pathogens, or also the lack thereof, as assessed by thorough surveillance at any mass gatherings with the exception of those in Saudi Arabia. A systematic search for relevant articles in the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Sixty-eight studies were identified. Although outbreaks have not been reported frequently in or after mass gatherings outside the Hajj and Umrah pilgrimages, they have sometimes occurred at Muslim, Christian, and Hindu religious events, at sports events, and at large-scale open air festivals. In this review it was found that the most common outbreaks at these mass gatherings involved vaccine preventable diseases, mainly measles and influenza, but also mumps and hepatitis A. Meningococcal disease has rarely been recorded. Additionally it was found that the transmission of various communicable diseases that may not be prevented by vaccination has been recorded in association with mass gatherings. These were mainly gastrointestinal infections, caused by a variety of pathogens. It was also noted that some outbreaks occurring at mass gatherings have resulted in the international spread of communicable diseases.

London 2012 Olympic and Paralympic Games: public health surveillance and epidemiology

Mass gatherings are regarded as potential risks for transmission of infectious diseases, and might compromise the health system of countries in which they are hosted. The evidence for increased transmission of infectious diseases at international sporting mass gatherings that attract many visitors from all over the world is not clear, and the evidence base for public health surveillance, epidemiology, and response at events such as the Olympics is small. However, infectious diseases are a recognised risk, and public health planning is, and should remain, a crucial part of the overall planning of sporting events. In this Series paper, we set out the planning and the surveillance systems that were used to monitor public health risks during the London 2012 Olympic and Paralympic Games in the summer of 2012, and draw attention to the public health issues-infectious diseases and chemical, radiation, and environmental hazards-that arose. Although the absolute risk of health-protection problems, including infectious diseases, at sporting mass gatherings is small, the need for reassurance of the absence of problems is higher than has previously been considered; this could challenge conventional public health surveillance systems. Recognition of the limitations of health-surveillance systems needs to be part of the planning for future sporting events.

Impact of the London 2012 Olympic and Paralympic Games on demand for microbiology gastrointestinal diagnostic services at the Public Health Laboratory London

Planning for the London 2012 Olympic and Paralympic Games at the Public Health Laboratory London was based on the requirement to meet potential increased demand with scalable capacity. The aim of this study was to determine the impact on demand for microbiology gastrointestinal diagnostic services during the Games period. Retrospective cross-sectional time-series data analysis was used to assess the number of gastrointestinal specimens received in the laboratory and the number of positive results. There was no increase in the number of gastrointestinal specimens received during the Games period, thus the Games had no impact on demand for microbiology gastrointestinal diagnostic services at the laboratory. There was a decrease in the number of public health specimens received for culture [incidence rate ratio = 0.34, 95% confidence interval (CI) = 0.13-0.86, P = 0.02] and a decrease in the number of culture positive community specimens (odds ratio = 0.59, 95 % CI = 0.40-0.85, P = 0.005), suggesting a decrease in gastrointestinal illness during the Games period. As previous planning assumptions were not based on actual specimen activity, the results of this study may modify the extent of additional planning for microbiological services required for mass gatherings.

International infectious disease surveillance during the London Olympic and Paralympic Games 2012: process and outcomes

Surveillance for possible international infectious disease threats to the Olympic and Paralympic Games in London, United Kingdom, was conducted from 2 July to 12 September 2012 by a collaborative team comprising representatives from the Health Protection Agency (Public Health England since April 2013), the European Centre for Disease Prevention and Control and the National Travel Health Network and Centre. Team members enhanced their usual international surveillance activities and undertook joint risk assessments of incidents identified as relevant through an agreed set of criteria designed for the Games and using tools developed for this purpose. Although team members responded to a range of international disease incidents as part of their routine roles during this period, no incident was identified that represented a threat to the Games. Six incidents were highlighted by the team that were likely to attract media attention and hence could generate political and public concern. Responding to such concern is an important aspect of the overall public health management of mass gathering events. The lessons learned about the process and outcomes of the enhanced international surveillance will help inform planning by future hosts of similar events.

Microbiological aspects of public health planning and preparedness for the 2012 Olympic Games

Although communicable diseases have hitherto played a small part in illness associated with Olympic Games, an outbreak of infection in a national team, Games venue or visiting spectators has the potential to disrupt a global sporting event and distract from the international celebration of athletic excellence. Preparation for hosting the Olympic Games includes implementation of early warning systems for detecting emerging infection problems. Ensuring capability for rapid microbiological diagnoses to inform situational risk assessments underpins the ability to dispel rumours. These are a prelude to control measures to minimize impact of any outbreak of infectious disease at a time of intense public scrutiny. Complex multidisciplinary teamwork combined with laboratory technical innovation and efficient information flows underlie the Health Protection Agency's preparation for the London 2012 Olympic and Paralympic Games. These will deliver durable legacies for clinical and public health microbiology, outbreak investigation and control in the coming years.

Weather and environmental hazards at mass gatherings

Introduction Reviews of mass gathering events have traditionally concentrated on crowd variables that affect the level and type of medical care needed. Weather and environmental hazards at mass gathering events have not been fully researched. This review examines these events and aims to provide future suggestions for event organisers, medical resource planners, and emergency services, including local hospital emergency departments. Methods A review was conducted using computerised data bases: MEDLINE, The Cochrane Library, HMIC and EMBASE, with Google used to widen the search beyond peer-reviewed publications, to identify grey literature. All peer-review literature articles found containing information pertaining to lessons identified from mass gathering disasters due to weather or environmental hazards leading to participant death, injury or illness were analysed and reviewed. Disasters occurring due to crowd variables were not included. These articles were read, analysed, abstracted and summarised. Results 20 articles from literature search were found detailing mass gathering disasters relating directly to weather or environmental hazards from 1988 – 2011, with only 17 cases found within peer-review literature. Two events grey literature from 2011 are due to undergo further inquiry while one article reviews an event originally occurring in 1922. Analysis of cases were categorised in to heat and cold-related events, lightning and storms and disease outbreak. Conclusions Mass gathering events have an enormous potential to place a severe strain on the local health care system, Prior health resource and environmental planning for heat & cold-related illness, lightning & storms, and disease outbreak can advance emergency preparedness and response to potential disasters. Citation: Soomaroo L, Murray V. Weather and Environmental Hazards at Mass Gatherings. PLoS Currents Disasters. 2012 Jul 31 Keywords: Mass Gatherings, Disasters, Sporting Events, Festivals, Concerts, Storm, Lightning, Cyclone, Hot-weather illness, Cold-weather illness, Disease, Public Health, Syndromic Surveillance Abbreviations: ALS – Advance Life support; BLS – Basic Life support; ED – Emergency Department; EMS – Emergency Medical Services; PPR – Patient Presentation Rate

Gastrointestinal disease outbreaks in cycling events: are preventive measures effective?

In 2009, following a bike race, a gastrointestinal illness outbreak affected many participants. A cohort study showed an attack rate of 16·3% with the main risk factor being mud splashes to the face. Considering these findings, in 2010 recommendations to participants in the bike race were issued and environmental control measures were implemented. In 2010, a retrospective cohort study using web-based questionnaires was conducted to measure the use of preventive measures and to assess risk factors associated with gastrointestinal illness. A 69% response rate was achieved and 11721 records analysed, with 572 (attack rate 4·9%) matching the case definition, i.e. participants reporting diarrhoea within 10 days of race. There was a clear increase in the use of mudguards (96·7% reported access to/receiving information on preventive measures) and a significant decrease in gastrointestinal illness. This may indicate that the measures have been effective and should be considered, both in terms of environmental control measures as well as individual measures.

Global perspectives for prevention of infectious diseases associated with mass gatherings

We assess risks of communicable diseases that are associated with mass gatherings (MGs), outline approaches to risk assessment and mitigation, and draw attention to some key challenges encountered by organisers and participants. Crowding and lack of sanitation at MGs can lead to the emergence of infectious diseases, and rapid population movement can spread them across the world. Many infections pose huge challenges to planners of MGs; however, these events also provide an opportunity to engage in public health action that will benefit host communities and the countries from which participants originate.

Outbreak of Escherichia coli 0157:H7 related to animal contact at a petting zoo

OBJECTIVE

To determine the cause of an outbreak of Escherichia coli 0157:H7 related to animal exposures so that further transmission could be prevented.

DESIGN

Description of laboratory investigations and a case control study.

SETTING

Agricultural pavilion at an annual fair in Ontario.

POPULATION

People with laboratory evidence of E coli 0157:H7 (seven people) and others with diarrhea (155 people) who called the health unit following a media release were interviewed. Animals that were accessed most frequently by the public in the agriculture pavilion were tested for E coli 0157:H7. In the case control study, a case was defined as someone with laboratory confirmed E coli 0157:H7, or someone who developed severe or bloody diarrhea two to eight days after attending the agricultural pavilion at the fair (61 people). A convenience sample of people who attended the agricultural pavilion but did not develop diarrhea was selected as the control group (89 people).

INTERVENTIONS

Human and animal E coli 0157:H7 specimens were subtyped. Cases and controls were interviewed using a standardized questionnaire.

RESULTS

Subtyping of the seven human isolates of E coli 0157:H7 revealed five that were of an extremely uncommon phage type. Three samples from goats and one from sheep at the petting zoo in the agricultural pavilion were of this same phage type. The case control study also implicated goats (odds ratio [OR] 3.65; 95% CI 1.63 to 8.52) and sheep (OR 2.94; 95% CI 1.33 to 6.57) from the petting zoo.

CONCLUSIONS

Results of this investigation suggest strongly that the goats and sheep from the petting zoo were the source of this outbreak of E coli 0157:H7.

Cattle, weather and water: mapping Escherichia coli O157:H7 infections in humans in England and Scotland

Entero-haemorrhagic Escherichia coli O157:H7 is a zoonotic pathogen, responsible for a relatively small number of food poisoning and illness outbreaks each year, when compared with other food-borne bacteria capable of causing infections in the population. Nevertheless, E. coli O157:H7 is a bacterial pathogen associated with severe human illnesses including bloody diarrhoea and haemolytic uremic syndrome occurring in both outbreak and sporadic settings. In England and Wales approximately 1% of all laboratory-confirmed cases of food poisoning are the result of E. coli O157:H7; however, in Scotland this figure increases to 3%. When the size of the population is taken into account and the rate of E. coli O157:H7 confirmed cases per 100,000 population is examined, the rate of E. coli 0157:H7 infections in Scotland is much greater than England and Wales. The routes of transmission have changed over time, with new routes of transmission such as farm visits emerging. The prevalence of E. coli O157:H7 has a seasonal dependency, with greater faecal shedding of the organism in the warmer months; this is directly mirrored in the increased reporting of E. coli O157:H7 infection among hospitalized patients. This review attempts to suggest why this phenomenon occurs, paying particular attention to weather, animal movement and private water supplies.

Escherichia coli O157:H7: animal reservoir and sources of human infection

This review surveys the literature on carriage and transmission of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the context of virulence factors and sampling/culture technique. EHEC of the O157:H7 serotype are worldwide zoonotic pathogens responsible for the majority of severe cases of human EHEC disease. EHEC O157:H7 strains are carried primarily by healthy cattle and other ruminants, but most of the bovine strains are not transmitted to people, and do not exhibit virulence factors associated with human disease. Prevalence of EHEC O157:H7 is probably underestimated. Carriage of EHEC O157:H7 by individual animals is typically short-lived, but pen and farm prevalence of specific isolates may extend for months or years and some carriers, designated as supershedders, may harbor high intestinal numbers of the pathogen for extended periods. The prevalence of EHEC O157:H7 in cattle peaks in the summer and is higher in postweaned calves and heifers than in younger and older animals. Virulent strains of EHEC O157:H7 are rarely harbored by pigs or chickens, but are found in turkeys. The bacteria rarely occur in wildlife with the exception of deer and are only sporadically carried by domestic animals and synanthropic rodents and birds. EHEC O157:H7 occur in amphibian, fish, and invertebrate carriers, and can colonize plant surfaces and tissues via attachment mechanisms different from those mediating intestinal attachment. Strains of EHEC O157:H7 exhibit high genetic variability but typically a small number of genetic types predominate in groups of cattle and a farm environment. Transmission to people occurs primarily via ingestion of inadequately processed contaminated food or water and less frequently through contact with manure, animals, or infected people.

Using the internet for rapid investigation of an outbreak of diarrhoeal illness in mountain bikers

In summer 2008, we investigated an outbreak of diarrhoeal illness in participants of a mountain-bike event in Wales (UK) which had been affected by heavy rain. We conducted a retrospective cohort study to investigate the cause using an internet-based questionnaire. Fifty-three percent of those contacted responded, and 161 (46·5%) out of the 347 responders, reported gastrointestinal symptoms. Median day of onset was 3 days following the event. Ten riders reported receiving a laboratory-confirmed diagnosis of Campylobacter. Multivariate logistic regression analysis identified the inadvertent ingestion of mud (OR 2·5, 95% CI 1·5-4·2, P<0·001) and eating 'other' food during the event (OR 2·1, 95% CI 1·2-3·6, P=0·01) as significant risk factors for illness. We concluded that the outbreak was caused by Campylobacter, spread to the riders by the inadvertent ingestion of mud which had been contaminated with sheep faeces from the rural course. Mountain-bike race organizers should consider microbiological hazards when risk-assessing potential race courses. The internet is an efficient tool for the investigation of outbreaks in computer-literate populations.

Verotoxigenic Escherichia coli O157:H7 from Swedish cattle; isolates from prevalence studies versus strains linked to human infections--a retrospective study

Background

Several cases of human infection caused by verotoxin-producing Escherichia coli (VTEC) O157:H7 in Sweden have been connected with cattle farm visits. Between 1996 and 2002, 18 farms were classified as the source of human cases with isolation of EHEC (Enterohaemorrhagic Escherichia coli) after VTEC O157:H7 had been isolated from cattle on those farms.

Results

Characterization by phage typing and molecular methods of the strains isolated from these 18 farms, including PCR for virulence genes (vtx₁, vtx₂ and variants thereof, eaeA and EHEC-hlyA) and Pulsed-Field Gel Electrophoresis (PFGE), demonstrated a cluster of very similar strains from 16 farms. All were of phage type 4, carried the genes encoding the verotoxins VT2 and VT2c, intimin, EHEC-haemolysin and flagellin H7 as shown by PCR, and had identical or very similar PFGE patterns. When analysing strains in a prevalence study of VTEC O157:H7 from cattle at slaughter as well as from an on-farm prevalence study of dairy cattle, using the same typing methods, a rather wide variation was observed among the isolated VTEC O157:H7 strains.

Conclusions

In Sweden, a limited group of genetically similar and highly pathogenic VTEC O157:H7 strains seem to predominate in direct or indirect transmission from cattle to man.

Prevalence of shiga-toxigenicEscherichia coliO157:H7 in adult dairy cattle

OBJECTIVE

To describe shiga-toxigenic Escherichia coil O157:H7 (STEC O157:H7) fecal shedding prevalence, seasonal fecal shedding patterns, and site-specific prevalence from the oral cavity, skin, and feces of dairy cattle.

DESIGN

Cross-sectional study.

ANIMALS

Adult dairy cattle from 13 herds in Louisiana.

PROCEDURE

Samples were cultured for STEC O157 by use of sensitive and specific techniques, including selective broth enrichment, immunomagnetic separation, monoclonal antibody-based O:H enzyme immunoassay serotyping, and polymerase chain reaction virulence gene characterization. Point estimates and 95% confidence intervals were calculated for fecal shedding prevalence as well as site-specific prevalence from the oral cavity, skin, and feces. Logistic regression was used to assess seasonal variation and differences at various stages of lactation with respect to fecal shedding of STEC O157 in cattle sampled longitudinally.

RESULTS

Summer prevalence in herds in = 13) was 38.5%, with a cow-level prevalence of 6.5%. Among positive herds, prevalence ranged from 3% to 34.6%. Samples from 3 of 5 herds sampled quarterly over 1 year yielded positive results for STEC O157. In herds with STEC O157, an increase in cow-level prevalence was detected during spring (13.3%) and summer (10.5%), compared with values for fall and winter. Site-specific prevalences of STEC O157:H7 from oral cavity, skin, and fecal samples were 0%, 0.7%, and 25.2%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data indicated that STEC O157:H7 was commonly isolated from dairy cows in Louisiana, seasonally shed, and isolated from the skin surface but not the oral cavity of cows.

Verotoxinogenic Escherichia coli (VTEC) O157:H7--a nationwide Swedish survey of bovine faeces

In the autumn of 1995 the first outbreaks of enterohemorrhagic Escherichia coli O157:H7 including ca 100 human cases were reported in Sweden. From outbreaks in other countries it is known that cattle may carry these bacteria and in many cases is the source of infection. Therefore, the present study was performed to survey the Swedish bovine population for the presence of verotoxin-producing E. coli (VTEC) of serotype O157:H7. Individual faecal samples were collected at the 16 main Swedish abattoirs from April 1996 to August 1997. Of 3071 faecal samples, VTEC O157 were found in 37 samples indicating a prevalence of 1.2% (CI_95% 0.8–1.6). All 37 isolates carried genes encoding for verotoxin (VT1 and/or VT2), intimin, EHEC-haemolysin and flagellin H7 as determined by PCR. Another 3 strains were of serotype O157:H7 but did not produce verotoxins. The 37 VTEC O157:H7 strains were further characterised by phage typing and pulsed-field gel electrophoresis. The results clearly show that VTEC O157:H7 is established in the Swedish bovine population and indicate that the prevalence of cattle carrying VTEC O157:H7 is correlated to the overall geographical distribution of cattle in Sweden. Results of this study have formed the basis for specific measures recommended to Swedish cattle farmers, and furthermore, a permanent monitoring programme was launched for VTEC O157:H7 in Swedish cattle at slaughter.

Verocytoxigenic Escherichia coli in animal faeces, manures and slurries

Animal wastes and effluents from farming operations, including manures and slurries, are frequently applied as fertilizer to land used for crop or silage production and cattle grazing. It is well documented that potentially harmful pathogens including verocytoxigenic Escherichia coli (VTEC) are shed in animal faeces and there is growing concern in many countries about the number of sporadic and outbreak cases of VTEC attributable to direct contact with faecal material either as a result of handling contaminated mud in fields or ingestion of produce grown in contaminated manures or slurries. VTEC has been detected in the faeces of ruminant and non-ruminant farmed animals, wild animals, domestic pets and birds and the pathogen appears to be well adapted to survive in animal faeces and can persist for extended periods ranging from several weeks to many months. Because of this persistence these materials are important as potential vehicles for transmission within herds, farms, the fresh food chain and the wider environment. Appropriate handling of bovine faeces is necessary to control spread of this pathogen and to limit the significant risks of human infection. It may be necessary to hold manure/slurry for extended periods prior to spreading on farmland, or for use in the production of food crops, particularly foods that are to be consumed in the raw or minimally processed state. Alternatively, it may be necessary to apply processes such as composting, heat drying or digestion which can expedite the decline of pathogens including VTEC in manures. However, there is a need for research work to develop economical and practical systems for treatment of manures and slurries. The risk from direct contact with faecal material at farms and petting zoos is also recognized and many public health authorities have put forward measures for strict practices to limit the risk of infection, particularly for young children visiting these environments.

Pathogen survival in swine manure environments and transmission of human enteric illness--a review

The influence of zoonotic pathogens in animal manure on human health and well-being as a direct or indirect cause of human enteric illness is examined. Available international data are considered, but the study is focused on the developing situation in western Canada, where it is certain there will be further rapid growth in livestock numbers, particularly hogs. Major pathogens considered are Escherichia coli O157:H7, Salmonella, Campylobacter, Yersinia, Cryptosporidium, and Giardia. Canada is now the leading exporter of pork internationally, but recent increases in production contrast with constant domestic levels of pork consumption and declining levels of foodborne illness caused by pork. Effects of increased levels of manure production are not quantifiable in terms of effects on human health. The presence of major pathogens in manure and movement to human food sources and water are considered on the basis of available data. Survival of the organisms in soil, manure, and water indicate significant variability in resistance to environmental challenge that are characteristic of the organisms themselves. Generally, pathogens survived longer in environmental samples at cool temperatures but differences were seen in liquid and solid manure. Based on actual data plus some data extrapolated from cattle manure environments, holding manure at 25 degrees C for 90 d will render it free from the pathogens considered above.

Prevalence of verotoxin-producing Escherichia coli (VTEC) in slurry, farmyard manure and sewage sludge in France

AIMS

The aims of the present study were to determine VTEC prevalence in manure, slurry and sewage sludge in France and to characterize the VTEC strains isolated (virulence genes and serotype).

METHODS AND RESULTS

Seven hundred and fifty-two samples from 55 farmyard manures, 136 bovine and porcine faeces, 114 slurries, 10 composts, and 437 samples from outflows of sewage wastewater treatment plants were analysed. Twenty-four percent contained isolates which were PCR positive for stx gene. Twenty-one VTEC strains were recovered from positive samples by colony hybridization: 76% of them were positive for stx(2) gene, 33% for stx(1) gene,and 19% for eae gene. One strain belonged to serotype O157:H7 and two others to serogroups O26 and O55, respectively.

CONCLUSIONS

Some of the VTEC strains isolated from environments in France should be considered as potentially pathogenic for humans.

SIGNIFICANCE AND IMPACT OF THE STUDY

Appropriate handling or use of manure, slurry and sewage sludge is necessary so that contamination of the environment and food by VTEC can be prevented.

Contact with farming environment as a major risk factor for Shiga toxin (Vero cytotoxin)-producing Escherichia coli O157 infection in humans

In a prospective, unmatched case-control study of sporadic Shiga toxin (Vero cytotoxin)-producing Escherichia coli O157 (STEC O157) infection in England, exposure to the farming environment emerged strongly as a risk factor (adjusted odds ratio = 2.45; 95% confidence intervals = 1.49-4.02; p=0.0004) posing further challenges and opportunities for prevention.