Severe infections caused by Salmonella Enteritidis PT8/7 linked to a private barbecue

A cohort study on a barbecue-associated Salmonella outbreak was conducted to describe the burden of disease and to identify the outbreak vehicle. Dose-response relationships were tested with Fisher's exact and Wilcoxon rank sum tests (alpha = 0·05). S. Enteritidis isolates were cultured and phage-typed. Information was available for 11 out of 14 individuals attending the barbecue; all were healthy young adults (median age 27 years). The attack rate was 100%. Three cases were hospitalized and two developed acute pancreatitis. The exposure common to all cases was a vegetable pasta salad that had been stored unrefrigerated for 23 h. Consuming higher doses was associated with longer median symptom duration (7 days vs. 4 days, P = 0·11). S. Enteritidis was found in the stools of nine barbecue guests. Phage type 8/7 was identified in the stools of the salad preparer and one barbecue guest. This outbreak shows that S. Enteritidis can cause serious infection in young healthy individuals without well-known risk factors.

Mumps outbreaks in vaccinated populations: are available mumps vaccines effective enough to prevent outbreaks?

Increased reports of mumps in vaccinated populations prompted a review of the performance of mumps vaccines. The effectiveness of prior vaccination with 1 dose of vaccine ranged from 72.8% to 91% for the Jeryl Lynn strain, from 54.4% to 93% for the Urabe strain, and from 0% to 33% for the Rubini strain. Vaccine effectiveness after 2 doses of mumps vaccine was reported in 3 outbreaks and ranged from 91% to 94.6%. There was evidence of waning immunity, which is a likely factor in mumps outbreaks, aggravated by possible antigenic differences between the vaccine strain and outbreak strains. Inadequate vaccine coverage or use of the Rubini vaccine strain accounted for the majority of outbreaks reviewed; however, some outbreaks could not be prevented, despite high vaccination coverage with 2 doses of the Jeryl Lynn vaccine strain. Our findings indicate the need for more-effective mumps vaccines and/or for review of current vaccination policies to prevent future outbreaks.

Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 2. Description of outbreaks by size, severity, and settings

This article is the second in a series of several by members of the Committee on the Control of Foodborne Illness of the International Association of Food Protection, and it continues the analysis of 816 outbreaks where food workers were implicated in the spread of foodborne disease. In this article, we discuss case morbidity and mortality and the settings where the 816 outbreaks occurred. Some of the outbreaks were very large; 11 involved more than 1,000 persons, 4 with more than 3,000 ill. The larger outbreaks tended to be extended over several days with a continuing source of infections, such as at festivals, resorts, and community events, or the contaminated product had been shipped to a large number of customers, e.g., icing on cakes or exported raspberries. There were five outbreaks with more than 100 persons hospitalized, with rates ranging from 9.9 to 100%. However, overall, the hospitalization rate was low (1.4%), and deaths were rare (0.11% of the 80,682 cases). Many of the deaths were associated with high-risk persons (i.e., those who had underlying diseases, malnutrition, or both, as in a refugee camp, or young children), but a few occurred with apparently healthy adults. An analysis of the settings for the food worker-related events showed that most of the outbreaks came from food service facilities (376 outbreaks [46.1%]), followed by catered events (126 outbreaks [15.4%]), the home (83 outbreaks [10.2%]), schools and day care centers (49 [6.0%]), and health care institutions (43 outbreaks [5.3%]). However, many cases resulted from relatively few outbreaks (< 30 each) associated with community events (9,726), processing plants (8,580), mobile/temporary service (5,367), and camps/ armed forces (5,117). The single most frequently reported setting was restaurants, with 324 outbreaks and 16,938 cases. Improper hygienic practices in homes, on picnics, or at community events accounted for 89 of the 816 outbreaks. There were 18 outbreaks associated with commercial travel in air flights, trains, and cruise ships over several decades, although only the last seems to be a major concern today. Sixteen outbreaks occurred where food, primarily produce, was harvested and shipped from one country to another. Sometimes the presence of an infected worker preparing food was only one of several factors contributing to the outbreak.