A common Salmonella Enteritidis sequence type from poultry and human gastroenteritis in Ibagué, Colombia / Un tipo de secuencia común de Salmonella Enteritidis de origen aviar y de humano con gastroenteritis en Ibagué, Colombia

Abstract Introduction: Salmonella Enteritidis is a major cause of human salmonellosis in the world, with contaminated eggs and raw chicken meat as the main routes of infection. The main Salmonella spp. serovars circulating in laying hen farms, the surface of eggs, and in raw chicken carcasses have been identified in Ibagué, Colombia. However, it is unknown whether those serovars are responsible for human gastroenteritis. Objective: To evaluate the genetic relationship between gastroenteritis and Salmonella Enteritidis isolates from poultry and humans using multilocus sequence typing (MLST). Materials and methods: Salmonella spp. was isolated from clinical cases of gastroenteritis (n=110). Antibiotic susceptibility tests, followed by serotyping and MLST were conducted and S. Enteritidis was compared to those from laying hen farms and marketed eggs. Results: Ten isolates of Salmonella spp. were obtained from the stools of people with gastroenteritis. The prevalence of Salmonella spp. in human stools was 9.09%, and S. Enteritidis (n=4), S. Typhymurium (n=2), S. Newport (n=1), S. Uganda (n=1), S. Grupensis (n=1), and S. Braenderup (n=1) were the main serotypes. MLST indicated that a common S. Enteritidis sequence type (ST11) was present in all three sources and showed the same antibiotic resistance pattern. Conclusion: Salmonella Enteritidis ST11 constitutes a link between consumption and manipulation of contaminated eggs and human gastroenteritis in Ibagué. Additional studies would be required to establish if other Salmonella serovars isolated from raw chicken meat are also associated with human gastroenteritis.

Resumen Introducción. Salmonella Enteritidis es una de las mayores causas de salmonelosis en el mundo; los huevos contaminados y la carne de pollo cruda son sus principales fuentes de infección. En Ibagué, Colombia, se han identificado los principales serovares que circulan en granjas, superficies de huevos y canales de pollo, pero se desconoce si esos serovares son responsables de la gastroenteritis. Objetivo. Evaluar la relación genética entre los aislamientos de Salmonella Enteritidis de aves de corral y de humanos con la gastroenteritis mediante tipificación de multiloci de secuencias (Multilocus Sequence Typing, MLST). Materiales y métodos. Se aisló Salmonella spp. de casos clínicos de gastroenteritis (n=110). Se hizo la prueba de sensibilidad antibiótica, así como la serotipificación y la tipificación mediante MLST, y se comparó S. Enteritidis de humanos con la hallada en granjas de gallinas ponedoras y en huevo comercializado (n=6). Resultados. Se aislaron 10 cepas de Salmonella spp. a partir de heces de humanos con gastroenteritis. Se obtuvo una prevalencia de Salmonella spp. de 9,09%, y se identificaron los serotipos S. Enteritidis (n=4), S. Typhymurium (n=2), S. Newport (n=1), S. Grupensis (n=1), S. Uganda (n=1) y S. Braenderup presentes en pacientes con gastroenteritis. Mediante la MLST, se comprobó que un tipo de secuencia común (ST11) de S. Enteritidis estuvo presente en todas las tres fuentes y presentó el mismo patrón de resistencia antibiótica. Conclusión. Salmonella Enteritidis ST11 constituye un vínculo entre el consumo y la manipulación de huevos contaminados, y la gastroenteritis en humanos en Ibagué. Se requieren estudios complementarios para conocer si otros serovares de Salmonella aislados de carne de pollo cruda también se asocian con la gastroenteritis en humanos.

Salmonella Alachua: causative agent of a foodborne disease outbreak

Objectives: The aim of this study is to report the occurrence of the first outbreak of food poisoning caused by Salmonella Alachua in Brazil, as well as the antimicrobial susceptibility and the genetic relatedness of Salmonella Alachua strains isolated from clinical and food samples. Material and methods: To elucidate the outbreak, an epidemiological investigation was carried out, and two samples of common food were tested - mayonnaise salad and galinhada (a traditional Brazilian dish of chicken and rice) - according to the Compendium of methods for the microbiological examination of foods. Five stool samples were tested employing classic methods for the isolation and identification of enterobacteria. Strains of Salmonella were characterized for antibiotic susceptibility according to the Clinical and Laboratory Stan- dards Institute guidelines (2013), and submitted to pulsed-field gel electrophoresis analysis, performed according to the Centers for Disease Control and Prevention PulseNet protocol. Results: A total of 94 people were interviewed after ingesting the food, 66 of whom had become ill. A 60-year old female patient who was hospitalized in a serious condition, developed septic shock and died two days after consuming the food. The presence of Salmonella Alachua was confirmed in all the analyzed stool samples, and in the two types of food. The five strains showed higher than minimum inhibitory concentration values of nalidixic acid (≥256 µg/mL) and reduced ciprofloxacin susceptibility (minimum inhibitory concentration = 0.5 µg/mL). The pulsed-field gel electrophoresis analysis revealed indistinguishable patterns in Salmonella Alachua strains isolated from clinical and food samples. Conclusion: The data presented herein confirm the foodborne disease outbreak. They also allowed for the identification of the source of infection, and suggest that products from poultry are potential reservoirs for this serotype, reinforcing the ...

Epidemiological Investigation of an Outbreak of Salmonellosis in Gyeongju, Korea / 예방의학회지

OBJECTIVES: A salmonellosis outbreak occurred within a community of Gyeongju residents who ingested catered food from a wedding in June 2009. We aimed to epidemiologically investigate the probable vehicle of the infection. METHODS: We conducted a retrospective cohort study on 34 local residents who ingested the wedding food. RESULTS: Among the 34 residents, 31 (91.2%) reported symptoms of infection after eating the food. Among all of the wedding foods, pan-fried foods were highly associated with the diarrheal attack rate. On bacteriological examination, Salmonella species were detected in the pan-fried foods among the leftover foods and in 17 of the 31 stool specimens from the cases. There were five different types of pan-fried foods, but the onset of symptoms was independent of the ingredients used. We found that the pan-fried food was prepared at a food store in Seoul and that eggs were a common ingredient. CONCLUSIONS: The major cause of the salmonellosis in this population was presumed to be the pan-fried food prepared with contaminated eggs. These food items might have been partially undercooked because of their irregular shape, which allowed the Salmonella species to survive and multiply before ingestion.

Brotes por Salmonella spp., Staphylococcus aureus y Listeria monocytogenes asociados al consumo de pollo / Outbreaks of Salmonella spp., Staphylococcus aureus and Listeria monocytogenes associated with poultry consumption. Systematic review.

Introducción. Las enfermedades transmitidas por alimentos son un serio problema de salud pública y, el pollo, uno de los alimentos asociados con ellas. Objetivo. Determinar la distribución y frecuencia de brotes alimentarios asociados al consumo de pollo contaminado por Salmonella spp., Listeria monocytogenes y Staphylococus aureus, mediante una revisión sistemática de la literatura científica. Materiales y métodos. Se buscaron los estudios de brotes asociados a Salmonella spp., S. aureus y L. monocytogenes, en las bases de datos Medline, Pubmed, Science Direct,SciELO,Librería Cochrane (CCRT),Biblioteca Virtual en Salud (BVS), Highwire,HINARI y MedicLatina. Se obtuvieron los datos para el cálculo de odds ratios (OR) mediante la elaboración de tablas de contingencia en el programa RevMan5™. Resultados. Siete artículos cumplieron con los criterios de inclusión y no se encontraron reportes de L. monocytogenes. El OR global fue de 3,01 (IC95% 2,37-3,81), lo que se interpreta como una asociación significativa entre el consumo de pollo contaminado y la infección alimentaria. Se presentó heterogeneidad en los estudios incluidos (p=0,03), por lo que fue necesario un análisis por subgrupos de microorganismos; para el caso de Salmonella spp., el OR fue de 2,67 (IC95% 2,09-3,41). No se hizo análisis para S. aureus por reportarse un solo artículo. Conclusiones. Se encontró un OR de 2,61, lo que indica que hay una fuerte asociación entre el consumo de pollo y la adquisición de salmonelosis. El principal factor de riesgo para adquirir salmonelosis es el consumo de pollo de asadero en los restaurantes.

Introduction. Food borne diseases are a serious public health problem. Poultry are often associated with these outbreaks. Objective. A systematic review of the literature is provided concerning the distribution and frequency of food borne outbreaks associated with consumption of chicken contaminated with Salmonella spp., Listeria monocytogenes and Staphylococcus aureus. Materials and methods. The search for studies of outbreaks associated with Salmonella, S. aureus and L. monocytogenes was conducted in Medline, Pubmed, Science Direct, Scielo, Cochrane Library (CCRT), Virtual Health Library (VHL), Highwire, HINARI and MedicLatina. Data were obtained for the calculation of odds ratio (OR) by preparing contingency tables using the RevMan5 program. Results. Seven articles met the inclusion criteria; however, no reports of L. monocytogenes were obtained. The overall OR was 3.01 (95% CI: 2.37, 3.81); this was interpreted as a significant association between the consumption of contaminated chicken and food poisoning. In the included studies heterogeneity (p= 0.03) was presented, so it took a subgroup analysis of microorganisms, in the case of Salmonella OR was 2.67 (95% CI: 2.09 -3.41). No analysis was made for S. aureus reported a single article. Conclusions. The OR indicated a strong association between chicken consumption and acquisition of salmonellosis. The main risk factor for acquiring salmonellosis is the consumption of chicken from grill restaurants.

Descripción clínica y epidemiológica de un grave brote de salmonelosis transmitida por alimentos / Clinical and epidemiological description of severe outbreak of foodborne infection by Salmonella Enteritidis

Background: Foodborne diseases have increased considerably. Aim: To report a foodborne outbreak, remarking the importance of early notification to activate the epidemiological surveillance system. Results: During February 2011 we observed a Salmonella Enteritidis outbreak. 31.6% of the cases were seen in the same Emergency Care Unit where all required intravenous fluid rehydration, and 41.7% were hospitalized because of severe dehydration. In the Emergency Room 45.5% of cases required a second visit to be diagnosed correctly. Discussion: Physicians under report the cases of this disease, delaying the activation of the epidemiological surveillance system. Conclusions: Besides providing good treatment to patients, physicians need to be qualified to recognize foodborne diseases and communicate early the suspicion of an outbreak to the epidemiological surveillance system in order to prevent new cases of disease in the community.

Introducción: Las enfermedades transmitidas por alimentos (ETA) han aumentado considerablemente. Objetivo: Reportar un grave brote de ETA destacando la importancia de la notificación precoz para la activación del sistema de vigilancia epidemiológica. Resultados: Durante febrero de 2011 se observó un brote de Salmonella Enteritidis. Un 31,6% de los casos fueron atendidos en un mismo servicio de urgencia, donde todos requirieron la administración de fluidos endovenosos y 41,7% fueron hospitalizados por deshidratación grave. El 45,5% de los casos necesitó de una segunda consulta para ser diagnosticados correctamente. Discusión: La identificación de pacientes integrantes de un brote de ETA es difícil en los servicios de urgencia y los médicos sub-reportan los casos, retrasando al sistema de vigilancia epidemiológica. Conclusiones: Junto con brindar un adecuado tratamiento, los médicos deben estar capacitados para reconocer las ETA y comunicar tempranamente la sospecha de un brote para prevenir nuevos casos en la comunidad.

Salmonella wien from gastroenteritis cases encountered in Mangalore, India : A report of 10 cases and review of the literature.

Ten cases of gastroenteritis due to S. Wien were reported from a tertiary care hospital in Mangalore, in the month of April 2008. Biochemically, it resembles S. Paratyphi B or S. Typhimurium. Serotyping was done at the Central Research Institute, Kasauli, to confirm the identity. The food source is more likely to be chicken or some poultry products. All the 10 cases recovered with symptomatic treatment including antimicrobials like fluoroquinolones. To the best of our knowledge, no documented report is available from India regarding the prevalence of this organism in humans.

A food borne outbreak of gastroenteritis due to shigella and possibly salmonella in a school.

On August 5, 2005, a private hospital reported a large number of students with gastrointestinal illness from the same school in Bangkok, Thailand. The Bureau of Epidemiology along with the Bangkok Metropolitan Administration investigated this outbreak, to determine risk factors, identify the source of infection and possible causative organism, and recommend prevention and control strategies. A case was defined as a person who was studying or working at School A and who developed abdominal pain, diarrhea, nausea or vomiting during the five-day period of August 4 to 8, 2005. A descriptive study was carried out for active case-finding, medical records review, and case interviews. We conducted the retrospective cohort study among third and fourth grade students. Stool samples were collected and tested at the Thai National Institute of Health and at private hospital laboratories. The overall attack rate was 37%. Main symptoms were diarrhea, fever, headache, abdominal pain, vomiting, and nausea. The highest attack rate (63%) was among fourth-grade students. Based on food-history data collected from ill and well students, a multiple logistic regression analysis showed that a mixed chicken and rice dish served for lunch on August 4 was associated with illness (OR 3.28, 95% CI 1.46-7.36). Among stools samples from 103 cases, Shigella group D was found in 18 cases, Salmonella group C in 5 cases, and Salmonella group E in 2 cases. This food borne outbreak of gastroenteritis was most likely caused by Shigella spp although the possibility of mixed contamination with Shigella and Salmonella spp cannot be ruled out. Food borne outbreaks such as this can be prevented through simple and effective hygienic measures.

Estandarización de una técnica para la detección de salmonella spp. util para manipuladores de alimentos mediante técnica de amplificación molecular / Standardization of a technique for the detection of salmonella spp. useful for food handlers by molecular amplification technique

El problema de las toxoinfecciones alimentarias es un problema de salud a nivel mundial, entre las que se encuentran las producidas por Salmonella spp.; la prevalencia de sus especies ha cambiado en los últimos años, además del bajo nivel de sensibilidad de los métodos tradicionales de aislamiento como es el caso del coprocultivo. Debido a esto el objetivo de este trabajo fue estandarizar una metodología molecular (PCR) para este patógeno a partir de muestras fecales; los resultados mostraron gran sensibilidad y especificidad, haciendo factible su utilización en manipuladores de alimentos.

Surtos de toxinfecção alimentar no município de Porto Alegre/RS, no período de 1995 a 2002 / Food-borne disease in the city of Porto Alegre /RS, from 1995 to 2002

O presente trabalho foi realizado com o objetivo de conhecer o perfil epidemiológico dos surtos de toxinfecção alimentar e a evolução das DTA ocorridos no município de Porto Alegre, no período de 1995 a 2002. Foram analisadas 150 relatórios finais de investigação de surtos. Os surtos analisados envolveram 7.373 pessoas. A faixa etária com maior número de comensais doentes (76 por cento) foi de 15-50 anos de ambos os sexos. O principal agente etiológico identificado nos surtos foi Salmonella spp (24 por cento), seguido por Staphylococcus aureus (12 por cento). Os sintomas mais freqüentes foram náuseas, cólicas abdominais e diarréia. Os principais alimentos envolvidos nestes surtos foram aqueles que continham ingredientes de origem animal (60 por cento). Foi possível relacionar 11 diferentes fatores predisponentes, sendo que refrigeração inadequada (33 por cento) foi o mais freqüente. Dos 159 surtos investigados, 44 por cento ocorreram em residências, 36 por cento em estabelecimentos comerciais e 11 por cento em restaurantes. Com os dados disponíveis, evidencia-se a necessidade de educar a população quanto aos riscos que os alimentos contaminados representam.

Outbreak of Salmonella oranienburg infection in Japan.

We experienced five cases of Salmonella oranienburg infection in children living in Saitama prefecture. Thereafter the number of patients with S. oranienburg infection increased not only in Saitama (55 cases) but also in other parts of Japan in 1999 (1505 cases) in 1999. The source of S. oranienburg infection was identified as a snack made from semi-dry cuttlefish.

Analysis of Salmonella enterica serotype Enteritidis isolated from human and chickens by repetitive sequence-PCR fingerprinting, antibiotic resistance and plasmid profiles

A total of 22 Salmonella enterica serotype Enteritidis (S. Enteritidis) strains isolated from human and chicken were subjected to DNA fingerprinting by repetitive sequence PCR using ERIC and BOX primers, antibiotic resistance and plasmid patterns. Both ERIC and BOX PCR amplification data revealed a highly genetic homogeneity between isolates from human and chicken except one isolate, which originated from chicken and showed a different DNA band pattern from others. Eleven of 22 S. Enteritidis isolates (50%) were resistant to more than one antibiotics and characterized by 5 resistance patterns. The most common pattern was penicillin resistant (63.6%). Only one isolate from chicken showed a multiple drug resistance patterns to 4 antibiotics. All 22 S. Enteritidis isolates harbored more than two plasmids with eight different plasmid profiles including two to six plasmids with approximate molecular size ranging from 1.9 to 21 kb. A band of 15 kb size was detected in all isolates tested, however, the band sizes smaller than 15 kb were found only in isolates from chicken.

Prevalência de Salmonella sp em suínos abatidos em frígoríficos do Rio Grande do Sul / Prevalence of Salmonella sp. carrier pigs in slaughterhouses of Rio Grande do Sul, Brazil

Este estudo foi realizado com o objetivo de determinar a prevalência de Salmonella sp em suínos abatidos em frigoríficos sob inspeção federal no Rio Grande do Sul. Amostras de fezes e linfonodos foram coletadas em três diferentes frigoríficos no Estado. A partir da análise microbiológica das amostras de 300 animais, encontrou-se uma prevalência de Salmonella sp de 55,66 por cento, com 17,6 por cento de isolamentos a partir dos linfonodos, 18,3 por cento das fezes e 19,6 por cento em ambos os materiais. Foram identificados 26 sorovares diferentes em 226 isolados de Salmonella sp. Os sorovares mais prevalentes foram: Typhimurium (24,3 por cento), Agona (19,9 por cento), Derby (13,2 por cento) e Bredeney (12 por cento). Estes resultados indicam a necessidade de implementar programas de controle com o objetivo de diminuir a prevalência de animais portadores ao abate.

Vigilancia epidemiológica de enfermedades transmitidas por alimentos en la Provincia de Río Negro, Argentina, 1993-2001 / Surveillance of foodborne diseases in the province of Rio Negro, Argentina, 1993-2001

A total of 39 outbreaks of foodborne diseases affecting 958 people in the province of Rio Negro, Argentina between 1993 and 2001 are described and evaluated. The main causal agents were identified involving food, sites of occurrence, risk factors and notification system used. Salmonella spp (38%), Trichinella spiralis (15%), Escherichia coli (13%) and Staphylococcus aureus (15%) were the most frequent agents present in outbreaks. Salmonella spp produced the largest number of cases (52%). Food involved were cooked meat (36%), cheese (10%), sandwiches (10%), deserts (10%) and ice cream (8%). Indeed, ice creams were involved in the largest number of cases and of people affected. In relation to the source of food, 41% of outbreaks were caused by homemade meals, 23% by catering or ice cream parlor, 13% in family parties, 8% in county fairs and 8% in hotel restaurants. In 28% of the outbreaks the etiological agent was identified exclusively by epidemiological analysis, in 64% isolation of the agent was carried out, and in 8% of the cases, a final diagnosis could not be obtained. Validity of epidemiological studies in foodborne disease, the necessity of strengthening the notification system of outbreaks, and the importance of good practices in food handling are analyzed.

Se describen 39 brotes de enfermedades transmitidas por alimentos que afectaron a 958 personasen la provincia de Río Negro, Argentina, en el período 1993- 2001. Se identifican los agentes causales, los alimentos involucrados, los sitios de ocurrencia, los factores de riesgo involucrados y los mecanismosde notificación empleados. Salmonella spp (38%), Trichinella spiralis (15%), Escherichia coli (13%) y Staphylococcus aureus (15%) resultaron los agentes más frecuentes en los brotes. Salmonella spp. tambiénprodujo el mayor número de casos (52%). Los principales alimentos involucrados resultaron cárneos (36%),quesos (10%), fiambres y sándwiches (10%), postres (10%) y helados (8%). El mayor número de casos, por suparte, fue causado por la ingestión de helados (37%). Con relación al origen de los alimentos, 41% de los brotesfueron causados por comidas elaboradas en los domicilios, 23% en establecimientos comerciales, 13% enfiestas familiares, 8% en fiestas comunitarias y 8% en restaurantes de hoteles. En el 28% de los brotes fueidentificado el agente etiológico por análisis epidemiológico exclusivamente, en el 64% se logró el aislamientodel agente, mientras que en el 8% de los casos no se logró el diagnóstico definitivo. Se analiza el valor de laencuesta epidemiológica en los estudios de enfermedades transmitidas por alimentos, la necesidad de fortalecerel sistema de notificación médica de casos y brotes y la importancia de las buenas prácticas en la manipulaciónde alimentos.

A Food-Borne Outbreak Caused by Salmonella Enteritidis

This study was designed to define the epidemiology of a food-borne outbreak caused by Salmonella enteritidis that affected only one squadron of a military battalion located in the vicinity of the city of Edirne in Turkey. The outbreak was analyzed by a standard surveillance form of the Centers for Disease Control and Prevention. The relationship between the eaten foods and cases was analyzed by Fisher's exact chi-square test, and odds ratios were calculated by a case-control study. The outbreak affected 60 of 168 soldiers in the squadron, 16 of whom were hospitalized. S.enteritidis was cultured in stools from 13 of the hospitalized soldiers and from 3 soldiers who had prepared the food. All strains were completely susceptible to antibiotics; their plasmid profiles were also identical. The highest attack rate detected was 55.7% in an omelet eaten 24 hours before (p < 0.001). Furthermore, it was the riskiest food according to the case-control study (OR=7.88; 95% CI=3.68-16.89). The food samples were unobtainable because they had been discarded. All of the hospitalized cases recovered, and none of the control cultures of stools yielded the pathogen after three weeks. In conclusion, although our results didn't indicate the exact source of the outbreak microbiologically, the omelet was considered to be the source based on the epidemiological proofs.

Salmonella enteritidis, un patógeno entérico ligado a la industria de los alimentos / Salmonella enteritidis, an enteric pathogen related to the industry of foods

Chile ha experimentado un cambio epidemiológico en la última década con la desaparición progresiva de la fiebre tifoidea, causada mayoritariamente por Salmonella Typhi y la emergencia epidémica de Salmonella Enteritidis, un agente de diarrea sin tratamiento antibiótico eficaz y ligado estrechamente a productos avícolas contaminados e inadecuadamente preparados. La fiebre tifoidea ha disminuido su importancia debido al desarrollo humano experimentado en Chile con un alto grado de cobertura de agua potable y de manejo de excretas que, en conjunto con un mayor nivel de educación, han limitado la contaminación del ambiente por este agente y la adquisición de él por huéspedes susceptibles. A pesar de este notable avance, un nuevo serotipo de Salmonella ha irrumpido en Chile, denominado Enteritidis, que ha logrado aprovechar el nuevo escenario obtenido con la industrialización avícola donde miles de aves convivenen pequeños espacios, facilitando la infección cruzada entre ellas. La contaminación intermitente de huevos, ya sea por vía transovárica o superficial, ha permitido la llegada de este agente en forma errática, pero persistente al ser humano. Este nuevo panorama obliga a que nuestro país adopte estrategias de prevención que involucran a productores, distribuidores y consumidores de productos avícolas

An outbreak of salmonellosis linked to a marine turtle.

In September 1998, an outbreak of gastroenteritis occurred in a coastal Aboriginal community in the Northern Territory over a seven day period. An investigation was conducted by the Center for Disease Control, Territory Health Services. Thirty-six cases were detected and 17% (n=6) were hospitalized. Salmonella chester was isolated from eight of nine stool specimens. Sixty-two percent of cases interviewed (n=28) reported consumption of a green turtle (Chelonia mydas) within a median of 24 hours prior to onset of illness. Of the remainder, all but two were contacts of other cases. Salmonella chester was isolated from a section of partially cooked turtle meat. There are no previous published reports of salmonellosis associated with consumption of sea turtles despite them being a popular food source in coastal communities in the Pacific.

An institutional outbreak of Salmonella enteritidis in Singapore.

A large outbreak of food poisoning occurred in Singapore in March 1995 when a total of 188 inmates in an institution was taken ill. Salmonella enteritidis was isolated from the stool cultures of 35 inmates (16 symptomatic and 19 asymptomatic). All the isolates were of the serotype profile 0:1, 9, 12 and H:g, m (antigen phase I); all were sensitive to ampicillin, ceftriaxone, chloramphenicol, co-trimoxazole and ciprofloxacin. Plasmid profile analysis and restriction enzyme fragmentation patterns (REFPs), as generated with EcoRI and HindIII, of a 60 kb plasmid obtained from these isolates were all identical, confirming that the outbreak resulted from a single source of infection. Stratified statistical analysis of food-specific attack rates strongly implicated imported canned luncheon pork consumed by the inmates on 26 March 95 as the single most probable cause of the food poisoning [p < 10(6), Mantel-Haenszel weighted odds ratio (OR) = 14.33; 95% confidence interval (CI) = 6.20-33.15]. The median incubation period of this outbreak was 19.3 hours and the median duration of illness was three days. The outbreak was rapidly brought under control through prompt implementation of epidemic control measures which comprised active search for diarrheal cases, rectal swabbing of asymptomatic inmates, isolation of those found to be infected, and maintenance of a high standard of personal, food and environmental hygiene.