[Foodborne outbreak by Clostridium perfringens in a school dining room]. / Brote de toxiinfección alimentaria por Clostridium perfringens en un comedor escolar.

BACKGROUND AND OBJECTIVE: The purpose was to investigate the etiology and epidemiological characteristics of a food-borne infection outbreak in a school dining room. SUBJECTS AND METHOD: Retrospective cohort study. Information about gastrointestinal symptoms and the use of the service of the school dining room was obtained. Coprocultures and detection of Clostridium perfringens enterotoxin in stool samples by means of reverse passive latex agglutination were carried out in 7 ill persons. Relative risks (RR) at 95% confidence intervals (95% CI) were calculated. RESULTS: The attack rate was 17.5% (48/275) and the probability of becoming sick was higher in students who ate at the second shift than in those eating at the first one (RR=13.8; 95% CI: 4.4-43.1). C perfringens enterotoxin was detected in 6 stool samples from patients. A high recount of C perfringens was not observed in those food samples kept frozen after their elaboration. CONCLUSIONS: The determination of C perfringens enterotoxin in feces allowed to confirm the etiologic agent of the outbreak.

[Nosocomial epidemic outbreak of acute gastroenteritis by Norwalk-like virus]. / Estudio de un brote epidémico nosocomial de gastroenteritis aguda por virus Norwalk-like.

BACKGROUND: From the notification of an acute gastroenteritis outbreak in a nursing home, an epidemiological study was started to determine the characteristics of the outbreak and its spreading pattern and to identify determining factors. PATIENTS AND METHOD: A study of historic cohorts was performed and the case was defined by the presence of diarrhea and vomiting. Spatial aggregation in double rooms was analyzed by a binomial distribution and temporal aggregation was analyzed by a relative risks model. The variables in the study allowed us to calculate the adjusted relative risk; the odds ratio was calculated in relation to the meal on day January 30. RESULTS: We studied 95.9% residents. The total attack rate was 28.7% (31.8% employees, 30.1% permanent residents and 15.2% day residents). The attack rate in rotation health personnel was 45.2%. Spatial and temporal spread in double rooms was negative. There was a significant association with the disease in rotator employees (RR = 3.22; CI 95%, 1.30-7.99; p = 0.02). No association was found between eating and disease (OR = 1.5; CI 95%, 0.4-6.1; p = 0.46). Norwalk-like virus was isolated in four faecal samples. CONCLUSIONS: This epidemic outbreak had the characteristic of a nosocomial infection with a likely person-to-person transmission mechanism. The main factor contributing to the spread of the infection was the existence of employees in permanent contact with residents with an important physical and mental impairment, hence highly dependent on the care provided by these health workers.

[A study of whooping cough epidemic outbreak in Castellon, Spain]. / Estudio de un brote epidémico de tos ferina en Castellón.

BACKGROUND: Based on the report of several cases at one school, a study of an epidemic outbreak was started for the purpose of characterizing this outbreak from the person, place and time standpoint, calculating the effectiveness of the immunization and the concordance of the cases with the positive result of the serological study. METHODS: A "case" is defined as being that individual who has a cough fasting for two weeks. A study is made of the spread of the disease by means of the epidemic curve and the effectiveness of the pertussis vaccine. The concordance of the cases and the positive serology is evaluated by way of the Kappa index. RESULTS: From among the students at several schools and those with whom they were living at the time, a total of 130 individuals were surveyed, 94 of whom fit the "case" definition. The average age of the cases was 10.5 years of age, 42.6% being males and 84% school age children, 71.3% showing signs of recent infection (positive IgM), the average length of time since the last whooping cough immunization being 8.25 years. The effectiveness of the whooping cough booster is 66%. The concordance between the cases and the positive results of the serology reveals a Kappa = 0.45. No B. Pertussis was isolated in the 25 throat swab samples. CONCLUSIONS: Classrooms and the family environment are a factor in spreading this disease. The including of a booster at 18 months improves the effectiveness of the whooping cough immunization. The isolation of B. Pertussis is not very frequent, and the serology may be an alternative when this disease is clinically suspected.