Mysterious outbreaks of gastrointestinal illness associated with burritos supplied through school lunch programs.

From October 1997 through March 1998, three outbreaks of gastrointestinal illness among school children were linked to company A burritos. In September 1998, a similar outbreak occurred in three North Dakota schools following lunches that included company B burritos. We conducted an investigation to determine the source of the North Dakota outbreak, identify other similar outbreaks, characterize the illness, and gather evidence about the cause. The investigation included epidemiologic analyses, environmental investigation, and laboratory analyses. In North Dakota, a case was defined as nausea, headache, abdominal cramps, vomiting, or diarrhea after lunch on 16 September 1998. Case definitions varied in the other states. In North Dakota, 504 students and staff met the case definition; predominant symptoms were nausea (72%), headache (68%), abdominal cramps (54%), vomiting (24%), and diarrhea (16%). The median incubation period was 35 min and median duration of illness was 6 h. Eating burritos was significantly associated with illness (odds ratio, 2.6; 95% confidence interval, 1.6 to 4.2). We identified 16 outbreaks that occurred in seven states from October 1997 through October 1998, affecting more than 1,900 people who ate burritos from two unrelated companies. All tortillas were made with wheat flour, but the fillings differed, suggesting that tortillas contained the etiologic agent. Results of plant inspections, tracebacks, and laboratory investigations were unrevealing. More than two million pounds of burritos were recalled or held from distribution. The short incubation period, symptoms, and laboratory data suggest that these outbreaks were caused by an undetected toxin or an agent not previously associated with this clinical syndrome. Mass psychogenic illness is an unlikely explanation because of the large number of sites where outbreaks occurred over a short period, the similarity of symptoms, the common food item, the lack of publicity, and the link to only two companies. A network of laboratories that can rapidly identify known and screen for unknown agents in food is a critical part of protecting the food supply against natural and intentional contamination.

Prevalence of infection with waterborne pathogens: a seroepidemiologic study in children 6-36 months old in San Juan Sacatepequez, Guatemala.

Water and sanitation interventions in developing countries have historically been difficult to evaluate. We conducted a seroepidemiologic study with the following goals: 1) to determine the feasibility of using antibody markers as indicators of waterborne pathogen infection in the evaluation of water and sanitation intervention projects; 2) to characterize the epidemiology of waterborne diarrheal infections in rural Guatemala, and 3) to measure the age-specific prevalence of antibodies to waterborne pathogens. Between September and December 1999, all children 6-36 months of age in 10 study villages were invited to participate. We collected sufficient serum from 522 of 590 eligible children, and divided them into six-month age groups for analysis (6-12, 13-18, 19-24, 25-30, and 31-36 months). The prevalence of antibodies was lowest in children 6-12 months old compared with the four older age groups for the following pathogens: enterotoxigenic Escherichia coli (48%, 81%, 80%, 77%, and 83%), Norwalk virus (27%, 61%, 83%, 94%, and 94%), and Cryptosporidium parvum (27%, 53%, 70%, 67%, and 73%). The prevalence of total antibody to hepatitis A virus increased steadily in the three oldest age groups (40%, 28%, 46%, 60%, and 76%). In contrast, the prevalence of antibody to Helicobacter pylori was relatively constant in all five age groups (20%, 19%, 21%, 25%, and 25%). Serology appears to be an efficient and feasible approach for determining the prevalence of infection with selected waterborne pathogens in very young children. Such an approach may provide a suitable, sensitive, and economical alternative to the cumbersome stool collection methods that have previously been used for evaluation of water and sanitation projects.

Epidemic and sporadic cases of nontuberculous mycobacterial keratitis associated with laser in situ keratomileusis.

PURPOSE: To report national case-finding results for nontuberculous mycobacterial keratitis and describe its association with laser in situ keratomileusis (LASIK). DESIGN: Enhanced passive disease reporting. METHODS: In April 2001, we investigated a California cluster of Mycobacterium chelonae keratitis associated with hyperopic LASIK using a contact lens mask. To identify other possibly related cases, the American Academy of Ophthalmology e-mailed its members asking them to report recent cases of nontuberculous mycobacterial keratitis to the Centers for Disease Control and Prevention. RESULTS: Forty-three additional cases of keratitis were reported (onsets between August 2000 and June 2001). Of these, 31 occurred as part of two unrelated LASIK-associated outbreaks. The 12 other reported cases occurred in sporadic fashion. Of the latter cases, 4 were associated with LASIK surgery. None of the reported cases were related to the M. chelonae cluster in California. CONCLUSIONS: Laser in situ keratomileusis-associated keratitis with nontuberculous mycobacteria may be more common than previously known.