Virus Pegged as Big Cause of Traveler's Diarrhea

THURSDAY, March 10 , 2005 (HealthDay News) -- The kind of diarrhea that can send U.S. travelers running from the beach to the bathroom is most likely caused by one of a family of pathogens called Norovirus, at least in Mexico, the Caribbean island of Antigua and the Central American country of Guatemala, researchers report.

Noroviruses were implicated in 65 percent of cases of traveler's diarrhea among tourists visiting those countries, according to a new study. And the researchers added that, the longer the traveler's trip south, the more likely it becomes Norovirus will catch up with them.

The finding should spur new research into preventing this all-too-common problem, researcher Kellogg J. Schwab, an assistant professor in the department of environmental health sciences at Johns Hopkins Bloomberg School of Public Health, said in a prepared statement.

"Noroviruses are known to be a major cause of food and waterborne gastroenteritis outbreaks in domestic and unique settings, such as cruise ships, and also have been documented among military groups during deployment overseas," he said. "However, few studies have investigated the prevalence of Norovirus infection among civilians traveling from industrialized to developing countries."

Reporting in the March issue of the Journal of Clinical Microbiology, Schwab's team analyzed stool samples from 34 people who suffered traveler's diarrhea during trips to Antigua, Guatemala or Cuernavaca, Mexico. Nearly two-thirds of them had at least one stool sample that tested positive for Norovirus, the researchers found.

The finding is relatively new, since molecular detection methods for these viruses have only recently been introduced into labs in the United States or other countries.

Study first author Amy R. Chapin, a doctoral candidate in the department of environmental health sciences at Bloomberg, noted that 11 of the Norovirus-positive stool samples also tested positive for E. coli bacteria. This suggests that dual infections among people with traveler's diarrhea may also be more common than previously thought.

The researchers said their findings indicate a need for further research into the role of Noroviruses in traveler's diarrhea.

More information

The U.S. National Center for Infectious Diseases has more about Noroviruses.