A large outbreak of Brainerd diarrhea associated with a restaurant in the Red River Valley, Texas.

BACKGROUND: In June 1996, an outbreak of chronic diarrhea was reported to the Texas Department of Health (Austin). METHODS: We initiated active case finding, performed 2 case-control studies, and conducted an extensive laboratory and environmental investigation. RESULTS: We identified 114 persons with diarrhea that lasted > or = 4 weeks. Symptoms among 102 patients who were studied included urgency (87%), fatigue (86%), fecal incontinence (74%), and weight loss (73%); the median maximum 24-h stool frequency was 15 stools. Diarrhea persisted for > 6 months in 87% and for > 1 year in 70% of patients who were observed. Fifty-one (89%) of 57 ill persons had eaten at a particular restaurant within 4 weeks before onset, compared with 8 (14%) of 59 matched control subjects (matched odds ratio [OR], undefined; 95% confidence interval [CI], 11.2-infinity). At the restaurant, patients were more likely than their unaffected dining companions to have drunk tap water (OR, 2.8; 95% CI, 1.0-9.9) and to have eaten several specific food items, and they were less likely to have drunk iced tea made from boiled water and store-bought ice (OR, 0.3; 95% CI, 0.05-1.0). A multivariable model that included consumption of tap water and salad bar tomatoes best fit the data. The restaurant had multiple sanitary and plumbing deficiencies. Extensive laboratory and environmental testing for bacterial, parasitic, mycotic, and viral agents did not identify an etiologic agent. CONCLUSIONS: The clinical, laboratory, and epidemiologic findings are consistent with those of previous outbreaks of Brainerd diarrhea. To our knowledge, this is the largest reported outbreak of Brainerd diarrhea associated with a restaurant.

Case-control study to determine risk factors for diarrhea among children during a large outbreak in a country with a high prevalence of HIV infection.

OBJECTIVES: Between January and March of 2006, over 35 000 diarrhea cases and 532 deaths were reported among children aged <5 years in Botswana. We conducted an investigation to characterize the outbreak, identify risk factors for diarrhea, and recommend control strategies. METHODS: We enrolled children <5 years of age presenting to the emergency department between March 2 and March 20, 2006. Cases had ≥3 loose stools per day and no antecedent diarrhea among household members. Controls had had no diarrhea since January 1, 2006. We conducted a multivariate logistic regression analysis controlling for socioeconomic status, age, and maternal HIV status. RESULTS: Forty-nine cases with median age of 12 months (range 0-45 months) and 61 controls with median age of 24 months (range 0-59 months) were enrolled; 33 (30%) were born to HIV-positive mothers. Case-parents were more likely to report storing household drinking water (adjusted odds ratios (AOR) 3.9, 95% confidence interval (CI) 1.2-15.7). Lack of hand washing after using the toilet or latrine (AOR 4.2, 95% CI 1.1-20.4) was more likely to be reported by case-parents. Case-children were less likely to be currently breastfeeding (AOR 30.3, 95% CI 2.0-1000.0). Five (10%) case-patients and no control-patients died. Multiple causal pathogens were identified. CONCLUSIONS: During this diarrhea outbreak in a country with a national program to prevent mother-to-child transmission of HIV, ill children were less likely to be breastfed and more likely to have been exposed to environmental factors associated with fecal contamination. These findings underscore the importance of adequate access to safe water, sanitation, hygiene, and nutrition education among populations using breast milk substitutes.

Hospitalization and mortality among primarily nonbreastfed children during a large outbreak of diarrhea and malnutrition in Botswana, 2006.

BACKGROUND: In 2006, a pediatric diarrhea outbreak occurred in Botswana, coinciding with heavy rains. Surveillance recorded a 3 times increase in cases and a 25 fold increase in deaths between January and March. Botswana has high HIV prevalence among pregnant women (33.4% in 2005), and an estimated 35% of all infants under the age of 6 months are not breastfed. METHODS: We followed all children <5 years old with diarrhea in the country's second largest referral hospital at the peak of the outbreak by chart review, interviewed mothers, and conducted laboratory testing for HIV and enteric pathogens. RESULTS: Of 153 hospitalized children with diarrhea, 97% were <2 years old; 88% of these were not breastfeeding. HIV was diagnosed in 18% of children and 64% of mothers. Cryptosporidium and enteropathogenic Escherichia coli were common; many children had multiple pathogens. Severe acute malnutrition (kwashiorkor or marasmus) developed in 38 (25%) patients, and 33 (22%) died. Kwashiorkor increased risk for death (relative risk 2.0; P = 0.05); only one breastfeeding child died. Many children who died had been undersupplied with formula. CONCLUSIONS: Most of the severe morbidity and mortality in this outbreak occurred in children who were HIV negative and not breastfed. Feeding and nutritional factors were the most important determinants of severe illness and death. Breastfeeding is critical to infant survival in the developing world, and support for breastfeeding among HIV-negative women, and HIV-positive women who cannot formula feed safely, may prevent further high-mortality outbreaks.

Identification of Vibrio isolates by a multiplex PCR assay and rpoB sequence determination.

Vibrio, a diverse genus of aquatic bacteria, currently includes 72 species, 12 of which occur in human clinical samples. Of these 12, three species--Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus-account for the majority of Vibrio infections in humans. Rapid and accurate identification of Vibrio species has been problematic because phenotypic characteristics are variable within species and biochemical identification requires 2 or more days to complete. To facilitate the identification of human-pathogenic species, we developed a multiplex PCR that uses species-specific primers to amplify gene regions in four species (V. cholerae, V. parahaemolyticus, V. vulnificus, and V. mimicus). The assay was tested on a sample of 309 Vibrio isolates representing 26 named species (including 12 human pathogens) that had been characterized by biochemical methods. A total of 190 isolates that had been identified as one of the four target species all yielded results consistent with the previous classification. The assay identified an additional four V. parahaemolyticus isolates among the other 119 isolates. Sequence analysis based on rpoB was used to validate the multiplex results for these four isolates, and all clustered with other V. parahaemolyticus sequences. The rpoB sequences for 12 of 15 previously unidentified isolates clustered with other Vibrio species in a phylogenetic analysis, and three isolates appeared to represent unnamed Vibrio species. The PCR assay provides a simple, rapid, and reliable tool for identification of the major Vibrio pathogens in clinical samples, and rpoB sequencing provides an additional identification tool for other species in the genus Vibrio.

Rotavirus antigenemia in patients with acute gastroenteritis.

Although rotavirus infections are generally considered to be confined to the intestine, recent reports suggest that extraintestinal disease occurs. We studied whether rotavirus infection was associated with antigenemia during a major outbreak of gastroenteritis in the Kingston metropolitan area, during July-August 2003. Rotavirus antigen was identified in 30 of 70 acute-phase serum samples (including from 2 deceased individuals) but in only 1 of 53 control samples. Serum antigen levels were inversely associated with time since symptom onset and were directly associated with antigen levels in stool (P = .02). Serum antigen levels were significantly elevated during primary infections (acute-phase serum immunoglobulin G [IgG] titers, <25), compared with those in subsequent infections (acute-phase serum IgG titers, > or = 25) (P = .02). Antigenemia was common in this outbreak and might provide a mechanism to help explain rare but well-documented reports of findings of extraintestinal rotavirus. In situations in which stool samples are not readily available (i.e., patients with severe dehydration or those recently recovered or deceased), serum testing by enzyme immunoassay offers a new and practical diagnostic tool.

Enterotoxin-producing Escherichia coli O169:H41, United States.

From 1996 to 2003, 16 outbreaks of enterotoxigenic Escherichia coli (ETEC) infections in the United States and on cruise ships were confirmed. E. coli serotype O169:H41 was identified in 10 outbreaks and was the only serotype in 6. This serotype was identified in 1 of 21 confirmed ETEC outbreaks before 1996.

Molecular, serological, and virulence characteristics of Vibrio parahaemolyticus isolated from environmental, food, and clinical sources in North America and Asia.

Potential virulence attributes, serotypes, and ribotypes were determined for 178 pathogenic Vibrio parahaemolyticus isolates from clinical, environmental, and food sources on the Pacific, Atlantic, and Gulf Coasts of the United States and from clinical sources in Asia. The food and environmental isolates were generally from oysters, and they were defined as being pathogenic by using DNA probes to detect the presence of the thermostable direct hemolysin (tdh) gene. The clinical isolates from the United States were generally associated with oyster consumption, and most were obtained from outbreaks in Washington, Texas, and New York. Multiplex PCR was used to confirm the species identification and the presence of tdh and to test for the tdh-related hemolysin trh. Most of the environmental, food, and clinical isolates from the United States were positive for tdh, trh, and urease production. Outbreak-associated isolates from Texas, New York, and Asia were predominantly serotype O3:K6 and possessed only tdh. A total of 27 serotypes and 28 ribogroups were identified among the isolates, but the patterns of strain distribution differed between the serotypes and ribogroups. All but one of the O3:K6 isolates from Texas were in a different ribogroup from the O3:K6 isolates from New York or Asia. The O3:K6 serotype was not detected in any of the environmental and food isolates from the United States, and none of the food or environmental isolates belonged to any of the three ribogroups that contained all of the O3:K6 and related clinical isolates. The combination of serotyping and ribotyping showed that the Pacific Coast V. parahaemolyticus population appeared to be distinct from that of either the Atlantic Coast or Gulf Coast. The fact that certain serotypes and ribotypes contained both clinical and environmental isolates while many others contained only environmental isolates implies that certain serotypes or ribotypes are more relevant for human disease.