Reusable Grocery Bag Fingered as Culprit in Norovirus Outbreak

Researchers found that a virus passed from one member of a girls’ soccer team to others via a grocery bag stored in a hotel bathroom where she was sick.

Researchers investigating a norovirus outbreak among members of a girls’ soccer team in October 2010 have discovered that the virus was spread by a reusable grocery bag. The findings were published online on May 8, 2012, in the Journal of Infectious Diseases.

The researchers began their investigation following reports of an outbreak of acute gastroenteritis among members of a soccer team from Oregon that had attended a soccer tournament in Washington State. They contacted representatives of the approximately 120 other teams that had been at the tournament and reviewed complaint logs of restaurants and hotels visited by the Oregon group to determine the extent of the illness. They also interviewed the members of the Oregon group, which consisted of 4 adult chaperones and 17 girls aged 13 to 14, about potential exposure to a sickening agent, any symptoms they experienced, and illnesses among other members of their households around the time of the tournament.

The investigation turned up no reports of similar outbreaks among any of the other teams at the tournament, nor among patrons of any of the restaurants or hotels visited by the Oregon group. The researchers learned that the initial illness case, a child, grew nauseated and developed abdominal pain on the Saturday evening of the tournament and moved into the hotel room of one of the chaperones. The sick child began vomiting and had diarrhea and was taken back to Oregon the next morning by the chaperone, who later became ill as well.

Among the other 19 members of the Oregon group, 7 cases of illness were identified, with a case defined as someone experiencing vomiting or diarrhea within 72 hours of returning from the tournament. For all of these cases, symptoms began on the Tuesday after the tournament.

Based on their interviews with members of the team, the researchers initially found a significant association between illness and consumption of packaged cookies during lunch on the Sunday of the tournament. Three of the 7 cases had eaten the cookies, while none of the 12 healthy attendees had eaten them. The researchers then determined that the cookies had been stored along with packaged chips and fresh grapes in a reusable grocery bag made of laminated woven polypropylene, which had been stored in the bathroom of the chaperone who cared for the initial case. The initial case reportedly never touched the bag, but repeatedly used the bathroom where it was stored.

The researchers found that illness was significantly associated with composite exposure to any item in the bag: all 7 of the ill subjects had contact with the cookies, the chips, or the grapes, compared with 4 of 12 who did not get sick. Evidence of norovirus with a similar sequence was found in the stool samples of all of the subjects who got sick. In addition, 2 of 10 swabs from the grocery bag tested positive for norovirus, although there was not enough sample to sequence the virus and compare it with that found in the stool samples. (The cookies, chips, and grapes were not available for testing.)

The researchers’ findings suggest that the virus from the initial case was aerosolized within the hotel bathroom and settled on the grocery bag and its contents. This demonstrates norovirus’s ability to pass from one person to another even without direct physical contact as well as the importance of being on guard against its spread.

“Although we certainly recommend not storing food in bathrooms, it is more important to emphasize that areas where aerosol exposures may have occurred should be thoroughly disinfected; this includes not only exposed surfaces but also objects in the environment that could serve as fomites,” write the researchers. (Fomites are inanimate objects that can transmit infectious agents.)

To read the study, click here.