Diarrhea caused by Shigella, rotavirus, and Giardia in day-care centers: prospective study.

We conducted a 19-month prospective study of children attending 20-day-care centers to determine the occurrence, causes, and transmission of gastroenteritis among children, staff, and family members. Nine centers had 15 outbreaks of diarrhea involving 195 patients. An enteropathogen was identified in all outbreaks. Shigella was detected in five outbreaks, rotavirus in two, giardia in one, and in the remaining seven multiple enteropathogens were identified. Rotavirus and Giardia occurred only in children less than 3 years of age; shigellosis occurred at all ages. In six DCC 68 single cases of diarrhea were not associated with an outbreak; an enteropathogen was identified in only three (4%) persons. Thirty-four family members (11%) developed diarrhea associated with the occurrence of gastroenteritis in children in six DCC evaluated for this problem. Secondary attack rates of diarrhea in families according to organisms identified in the DCC outbreaks were: Shigella 26%, rotavirus 15%, and G. lamblia 17%. DCC may play an important role in the epidemiology and transmission of gastroenteritis in the United States.

Prevention of traveler's diarrhea (emporiatric enteritis). Prophylactic administration of subsalicylate bismuth).

The efficacy of a daily dosage regimen of subsalicylate bismuth in preventing or reducing the severity of diarrhea among young healthy adults was evaluated in a double-blind, randomized, placebo-controlled trial. Diarrhea developed in 14 (23%) of 62 students receiving subsalicylate bismuth compared with 40 (61%) of 66 students taking a placebo. The protective effect of subsalicylate bismuth was apparent within a day or two of the study onset and became more obvious as the number of days at risk increased. The students treated with subsalicylate bismuth experienced fewer intestinal complaints and were less likely to pass soft or watery stools of any number. Once diarrhea occurred, enteropathogens were less commonly identified in stools of students receiving subsalicylate bismuth (33%) compared with placebo (71%). Subsalicylate bismuth was well tolerated by students during the 21-day trial.

Etiology of gastroenteritis among Americans living in the Philippines.

Between December 1975 and June 1976, American military personnel with diarrhea who were seen at an outpatient clinic at Clark Air Force Base Hospital were investigated to determine the etiology of their disease. Enterotoxigenic Escherichia coli were detected in 16% (18/115), rotavirus in 4% (4/111), salmonellae in 3% (3/115), shigellae in 2% (2/115) and Giardia lamblia in 2% (3/152) of patients with diarrhea. Thus from only 27% of the subjects studied were identifiable potential pathogenic agents found. The incidence of gastroenteritis increased in May and June with the increase in rainfall; however, there was no increase in the proportion of diarrhea caused by any of these identifiable enteric pathogens. Americans experienced a seasonal increase of diarrhea similar to that affecting the Philippine population in Manila. Enterotoxigenic E. coli was the most common identifiable enteric pathogen among Americans with diarrhea at Clark Air Force Base in the Philippines during the study, though even in these cases, it may not have been the agent responsible for their illness.

Human rotavirus in an adult population with travelers' diarrhea and its relationship to the location of food consumption.

The role of human rotavirus in adult diarrhea was evaluated in 164 newly arrived US students attending summer school at an urban Mexican university. Rotavirus was identified in stool samples by electron microscopy. Rotavirus was found in 26 of 109 students with diarrhea (24%) and in 8 of 55 asymptomatic control students (15%). Although bacterial pathogens were recovered from virus positive students with diarrhea, viral shedding also occurred independently of other agents. Clinical disease in students excreting only rotavirus tended to be mild and was accompanied by a low density of viral shedding. Food consumption in the home and at public eating establishments was examined the week before illness. While the location of food consumption was found to be important in the acquisition of diarrhea, there was no apparent relationship of the site where meals were eaten and the acquisition of rotavirus by students newly arrived in Mexico. These data support our previous study in a US student population residing in a rural setting in Mexico and implicate rotavirus as a cause of diarrhea among students traveling to Mexico from the United States. The present study offers additional evidence that rotavirus infection in this population might be spread by a nonfood vehicle of transmission which differs from spread of enterotoxigenic E coli, Shigella, or Salmonella strains in the same population.

Prospective study of enteropathogens in children with diarrhea in Houston and Mexico.

During a 22-month period, 595 children with diarrhea and 210 age-matched controls attending clinics in Houston (367 children) and Mexico (438) were prospectively evaluated for enteric pathogens. Enteropathogens associated with disease were Shigella (18%), rotavirus (14%), Salmonella (9%), toxigenic Escherichia coli (6%), and others (12%), including 14 Proteus isolates that caused rounding of adrenal cells. Enteropathogens were isolated from a greater (P less than 0.001) number of children with diarrhea (59%) than from asymptomatic controls (6%). Paired sera tested for antibody to heat-labile toxin of E. coli rarely demonstrated a fourfold rise during episodes of diarrhea. This study demonstrates: (1) more striking illness in children from Mexico; (2) more common occurrence of Shigella in Houston, and of rotavirus and Salmonella in Mexico; (3) lack of seasonal occurrence of rotavirus isolation in either population and a summertime occurrence of Shigella in Houston; (4) lack of toxigenic E. coli isolation in endemic diarrhea of either population; and (5) a significant (P less than 0.001) age-related acquisition of E. coli LT antibodies.

Rotavirus in travelers' diarrhea: study of an adult student population in Mexico.

The role of rotavirus in adult diarrhea was evaluated in 165 students attending a Mexican university. Students were divided into three groups: newly arrived summer students from the United Sttes, regular students from the United States, and Mexican and Venezuelan students. Ninety-one students with diarrhea and 74 corresponding, matched, asymptomatic control students were included in the study. The frequency of rotavirus in stools was determined by electron microscopy with use of the pseudoreplica technique. Twenty-five percent of those who were ill and 12% of the controls had rotavirus in their stools. A significantly (P less than 0.05) greater number of newly arrived United States summer students with diarrhea had rotavirus in their stool than did matched controls (26% vs. 3%). There was no significant difference in rate of recovery of bacterial pathogens from rotavirus-positive and rotavirus-negative stools (52% vs. 53%) from students with diarrhea. Although significantly more rotavirus was identified from ill American summer students than from controls, the role of rotavirus as a cause of diarrhea in these students could not be established in all cases since bacterial pathogens were also commonly found in stool.