Enteric Outbreaks Research Articles

Review of enteric outbreaks in prisons: Effective infection control interventions

Objectives To identify documented outbreaks, worldwide, of enteric illness in correctional facilities over the last 10 years to understand the epidemiology of the outbreaks and explicitly identify effective infection control measures. Study design Review of literature and outbreak investigation reports. Methods Computer-aided searches of literature databases and systematic searches of government websites were completed to identify relevant outbreak reports. Reference lists were hand-searched to validate the electronic search methodology. Reports identified through personal communications with public health officials were also included. Results Of the 72 outbreaks meeting the inclusion criteria, 76% and 21% were associated with bacterial agents and viral agents, respectively. The majority of outbreaks were associated with Salmonella ( n = 20), Clostridium perfringens ( n = 14), norovirus ( n = 14), pathogenic Escherichia coli ( n = 10) and Campylobacter spp. ( n = 5). Transmission was primarily foodborne (67%). During an outbreak, the most common control measures included limiting movements of ill inmates and staff, and their exclusion from kitchen duty. The most common retrospectively reported preventative recommendations included monitoring food temperatures and effective infection control procedures. Conclusions It is essential to monitor food temperatures to prevent enteric outbreaks in prisons. Training in safe food handling should be offered to inmates who work in the kitchen. Enteric outbreaks are best controlled by effective infection control practices, while active surveillance and early diagnosis may prevent further spread of illness.

Screening Policies for Daycare Attendees

Control measures for enteric outbreaks in child care settings frequently include screening by stool cultures from symptomatic children only. We present evidence from an investigation of Escherichia coli (E. coli) O157:H7 in a daycare in Waterloo, Ontario to support implementation of a mandatory screening policy for all children during an outbreak. In addition to routine outbreak control measures employed by the health unit, stool samples from all children and staff were collected, with positive E. coli cultures typed by pulsed field gel electrophoresis (PFGE). We conducted a cohort study, using data from the environmental investigation and questionnaires administered to parents and staff, to look for risk factors for infection and to survey parent/staff knowledge regarding appropriate management of diarrhea. Overall 11 E. coli O157:H7 cases were identified (7 lab-confirmed); 9 were children. No common source of infection was identified. Factors identified as possibly contributing to person-to-person transmission within the daycare included: i) the underreporting and possible attendance of symptomatic children despite alerting parents to the outbreak and requirements to keep symptomatic children at home, ii) possible transmission from an asymptomatic infected child, and iii) inconsistent understanding among parents and staff regarding diarrhea and appropriate management of a child with diarrhea. This investigation reveals that in child care settings, E. coli O157:H7 outbreak screening policies based on reported symptoms only may be insufficient. We recommend that such policies be amended to include the collection of at least one stool culture from all children in attendance, regardless of symptom history.

Screening policies for daycare attendees: lessons learned from an outbreak of E. coli O157:H7 in a daycare in Waterloo, Ontario.

Control measures for enteric outbreaks in child care settings frequently include screening by stool cultures from symptomatic children only. We present evidence from an investigation of Escherichia coli (E. coli) O157:H7 in a daycare in Waterloo, Ontario to support implementation of a mandatory screening policy for all children during an outbreak. In addition to routine outbreak control measures employed by the health unit, stool samples from all children and staff were collected, with positive E. coli cultures typed by pulsed field gel electrophoresis (PFGE). We conducted a cohort study, using data from the environmental investigation and questionnaires administered to parents and staff, to look for risk factors for infection and to survey parent/staff knowledge regarding appropriate management of diarrhea. Overall 11 E. coli O157:H7 cases were identified (7 lab-confirmed); 9 were children. No common source of infection was identified. Factors identified as possibly contributing to person-to-person transmission within the daycare included: i) the underreporting and possible attendance of symptomatic children despite alerting parents to the outbreak and requirements to keep symptomatic children at home, ii) possible transmission from an asymptomatic infected child, and iii) inconsistent understanding among parents and staff regarding diarrhea and appropriate management of a child with diarrhea. This investigation reveals that in child care settings, E. coli O157:H7 outbreak screening policies based on reported symptoms only may be insufficient. We recommend that such policies be amended to include the collection of at least one stool culture from all children in attendance, regardless of symptom history.

Gatekeepers of health: A qualitative assessment of child care centre staff's perspectives, practices and challenges to enteric illness prevention and management in child care centres

BackgroundEnteric outbreaks associated with child care centres (CCC) have been well documented internationally and in Canada. The current literature focuses on identifying potential risk factors for introduction and transmission of enteric disease, but does not examine why these risk factors happen, how the risk is understood and managed by the staff of CCCs, or what challenges they experience responding to enteric illness. The purpose of this study was to explore the understanding, knowledge and actions of CCC staff regarding enteric illness and outbreaks, and to identify challenges that staff encounter while managing them.MethodsFocus groups were conducted with staff of regulated CCCs in Southern Ontario. Five focus groups were held with 40 participants. An open ended style of interviewing was used. Data were analyzed using content analysis.ResultsCCC staff play an important role in preventing and managing enteric illness. Staff used in-depth knowledge of the children, the centre and their personal experiences to assist in making decisions related to enteric illness. The decisions and actions may differ from guidance provided by public health officials, particularly when faced with challenges related to time, money, staffing and parents.ConclusionCCC staff relied on experience and judgment in coordination with public health information to assist decision-making in the management of enteric illness and outbreaks. Advice and guidance from public health officials to CCC staff needs to be consistent yet flexible so that it may be adapted in a variety of situations and meet regulatory and public health requirements.

Enteric outbreaks in long-term care facilities and recommendations for prevention: a review

Outbreaks of enteric illness in long-term care facilities (LTCFs) were reviewed to identify preventative recommendations. Systematic review methodology identified outbreak reports of gastrointestinal illness in LTCFs either published or that occurred from January 1997 to June 2007. The inclusion criteria captured 75 outbreaks; 23 (31%) associated with bacterial agents and 52 (69%) with viral agents. Transmission was mainly foodborne (52%) for those of bacterial origin and person-to-person (71%) for viral outbreaks. Norovirus infection was associated with 58% of hospitalizations. Sixty deaths were reported, about half from Salmonella infections. Recommendations for foodborne outbreaks emphasized appropriate sourcing and preparation of eggs, staff training, and temperature control during food preparation. Recommendations from outbreaks transmitted person-to-person centred on controlling residents' movements, effective environmental cleaning and disinfection, cancelling social events and restricting visitors, excluding ill staff, encouraging effective hand hygiene, and preventing cross-contamination through gloving and gowning. In none of the 75 published outbreak reports were the suggested recommendations evaluated for effectiveness in controlling the outbreak. Applied research of this type could greatly help in the acceptance of prevention and control strategies.

Fault tree analysis of the causes of waterborne outbreaks

Prevention and containment of outbreaks requires examination of the contribution and interrelation of outbreak causative events. An outbreak fault tree was developed and applied to 61 enteric outbreaks related to public drinking water supplies in the EU. A mean of 3.25 causative events per outbreak were identified; each event was assigned a score based on percentage contribution per outbreak. Source and treatment system causative events often occurred concurrently (in 34 outbreaks). Distribution system causative events occurred less frequently (19 outbreaks) but were often solitary events contributing heavily towards the outbreak (a mean % score of 87.42). Livestock and rainfall in the catchment with no/inadequate filtration of water sources contributed concurrently to 11 of 31 Cryptosporidium outbreaks. Of the 23 protozoan outbreaks experiencing at least one treatment causative event, 90% of these events were filtration deficiencies; by contrast, for bacterial, viral, gastroenteritis and mixed pathogen outbreaks, 75% of treatment events were disinfection deficiencies. Roughly equal numbers of groundwater and surface water outbreaks experienced at least one treatment causative event (18 and 17 outbreaks, respectively). Retrospective analysis of multiple outbreaks of enteric disease can be used to inform outbreak investigations, facilitate corrective measures, and further develop multi-barrier approaches.

Molecular Subtyping and the Transformation of Public Health

Molecular Subtyping and the Transformation of Public Health

A LARGE OUTBREAK OF PROBABLE ROTAVIRUS IN NUSA TENGGARA TIMUR, INDONESIA

An outbreak of acute diarrheal disease was reported in Kupang, Nusa Tenggara, Indonesia, in August 2002. An investigative team carried out a retrospective historical review of records, and a case-control study involving data and specimen collections. Etiologic determination involving stool specimens was based on an enzyme-linked immunosorbent assay, with a reverse transcriptase-polymerase chain reaction performed for serotyping purposes. Two thousand six hundred probable cases were identified from hospital records during the outbreak months of June, July, August, and September 2002. Previous enteric outbreaks were recognized from the same months in the preceding years and all annual outbreak episodes following a period of prolonged, low rainfall. In contrast to previous outbreaks discerned from trend analysis, the overwhelming burden of disease fell upon the pediatric population versus the young and old in previous outbreak instances. Rotavirus was found to be the causative etiology, with serotype 1 predominating.

Stool Survey of Asymptomatic Diapered Children in Day Care

A survey of diaper-wearing children in community-day-care centers was conducted by the San Diego Department of Health Services during the period February-April 1986 to determine the presence of enteric pathogens in asymptomatic children. Written consent to collect stool samples from diapers was obtained from parents of children at four preschools. No reportable enteric diseases or outbreaks had occurred at the schools in the preceding year. For each child, the preschool teachers maintained a record of symptoms (eg, diarrhea, fever) during the week of stool collection. Stool specimens were collected from 63 diapered children. The samples were examined for parasites and cultured for bacteria and viruses. Giardia lamblia was identified in 18% to 32% of stool samples collected from children at three of the four centers. Prevalence of Giardia varied with the age of the child (0% age <12 months to 33% age <23 months). Microscopic examinations for Cryptosporidium and pathogenic amoeba were negative. Stool cultures were negative for Salmonella, Shigella, and Campylobacter. The prevalence of adenoviruses identified by viral cultures ranged from 32% to 80% at four sites. Echovirus was isolated from 36% of samples at one center. All stools were negative for rotavirus. Giardia was identified in the stools of 22% of children in day care in the absence of diarrhea or of concurrent illness. These findings indicate that asymptomatic infection with Giardia occurs commonly among children attending day-care centers. The lack of any documented outbreak or symptoms of enteric disease among attendees suggests that these asymptomatic children with Giardia need not be excluded from day care.

Prevalence of Rotavirus on High-Risk Fomites in Day-Care Facilities

The objective of this study was to determine the prevalence of rotavirus contamination on environmental surfaces in day-care environments, using the polymerase chain reaction technique. High-risk fomites were identified in two day-care centers and sampled biweekly during a 6-month study period. Water samples from water-play tables in each center were also collected during the study period. During an infectious disease outbreak, fomites were sampled from the rooms in which the outbreak occurred. Reverse transcriptase/polymerase chain reaction was carried out for viral detection of rotavirus from the fomites, and standard bacteriologic measures were used to detect bacteria in samples from water-play tables. A total of 96 fomite samples were tested for presence of rotavirus from the two centers, of which 18/96 (19%) tested positive for rotavirus. The timing of the positive samples differed between the two centers. In the center that housed infants, a peak of rotavirus-positive fomites coincided with two enteric outbreaks. Rotavirus contamination was found on the telephone receiver, drinking fountain, water-play table, and toilet handles in both centers. Bacteria in large quantities were also identified in water-play table samples. Moist surfaces including the telephone, water fountains, and water-play tables are common sources of rotavirus contamination within the day-care environment. Until a safe and affordable drug or vaccine against rotavirus is available for general use, avoidance of rotaviral infections is the most effective method for the prevention of rotavirus gastroenteritis.

Epidemiology of Aeromonas Infections in California

In May 1988, California became the first state to make aeromonas infection a reportable condition, thereby permitting the first population-based study of the epidemiology of infection caused by Aeromonas organisms. Case investigations were carried out on 219 of the 280 patients whose infections were reported during the first year of notification. The overall incidence rate for Aeromonas isolation was 10.6 cases per 1 million population. The gastrointestinal tract was the most commonly reported site from which Aeromonas was isolated (81%), with wounds being the next most common source (9%). Five (2%) of the 219 patients died; all five had serious underlying medical conditions apart from aeromonas infection. No common-source enteric outbreaks were reported. The high rate of gastrointestinal symptoms and isolation of organisms from medically vulnerable patients and the fact that other bacterial enteric pathogens were rarely isolated from symptomatic patients support evidence from previous studies that Aeromonas is an enteric pathogen. The evidence from these case reports in California suggests that aeromonas infections are not an important public health problem and are largely nonpreventable. Thus, public health surveillance is not necessary and mandatory reporting has been discontinued.

Double enteric infection ('la fièvre typhoide intriquée'); an account of an epidemic.

1. A double enteric infection is defined as the simultaneous infection of an individual or group of individuals with two organisms of the enteric group. The literature of the previously recorded cases and epidemics, in which the diagnosis of double enteric infection has been established by cultural methods, is reviewed.2. An account is given of a double enteric outbreak of seventy–six cases which occurred amongst British troops and police at Acre, Palestine, in 1948. The infection is thought to have been due to contamination of the water supply with sewage during the civil disturbances. The diagnosis was established bacteriologi–cally in seventy-four cases (93.3%);Salm. typhiwas isolated in forty–three cases,Salm. paratyphiB in three, and bothSalm. typhiandSalm. paratyphi Bfrom twenty–eight cases. There were three fatal cases in the epidemic (mortality rate = 3·94%).3. The morbidity rate from enteric fever among the infantry unit was 60%, and among the Palestine police, 17%. The possible reasons for this difference is discussed, and the conclusion drawn that it was probably due to the Palestine policemen being older men, with longer overseas service and more 'seasoned' to life in subtropical conditions.4. Thirteen cases were treated with polymyxin B (15 mg. 4-hourly for 4-day periods); with this small dose no beneficial therapeutic effects were observed, and ten cases showed evidence of renal damage while under treatment.5. The bacteriology, epidemiology and clinical aspects of double enteric infections are discussed. The diagnosis of a double enteric infection may be established with the greatest certainty by blood culture. Such infections are usually water-borne or milk-borne, and tend to occur when there has been a severe breach of hygiene, e.g. in the contamination of a water supply by sewage. The claim that the prognosis in instances of double enteric infection is worse than with single infections is not supported by the experiences at Acre where the three fatal cases occurred in cases infected withSalm. typhialone.

Chlorination of Water Supplies

AT the recent annual meeting of the British Waterworks Association, Prof. P. S. Lelean dealt with the history and present state of the methods of chlorina-tion of water supplies. The process was used in 1897 after an enteric outbreak at Maidstone, and its application on a large scale began in 1900 at Ostend; but the modern process, in which much smaller amounts of chlorine are used, was first put into operation in connexion with the London supplies on the initiative of the late Sir Alexander Houston. The method was extensively used during the War, when perfectly safe drinking water was procured in large amounts from canals and other sources of highly polluted water. In modern practice, bleaching powder has been replaced by chlorine from liquid chlorine. One part of chlorine in ten millions can reduce Bacillus coli from 1,000 to 2 per c.c. in ten minutes. The chloramines formed by the action of chlorine on ammoniated water, however, are much more effective than chlorine alone. In the case of Thames water, an addition of 0-1 parts per million of ammonia, filtration, and addition of 0-25 parts per million of chlorine resulted in the absence of B. coli from 98 per cent of the samples of 100 c.c. Growth from spores is also considerably retarded. The process causes neither taste nor odour. Prof. Lelean dealt with many aspects of water chlorination in detail, and his lecture emphasised the very great service rendered to public health by the use of scientific methods by the authorities responsible for water supplies: in London, 280million gallons per day are treated.