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.