Outbreak of Acute Gastroenteritis at a Music Festival in Ariège on the Weekend of July 20–21 – Update as of July 26, 2013

Following a report to the Midi-Pyrénées Regional Health Agency (ARS) on July 22 regarding several cases of acute gastroenteritis (AGE) that occurred during a music festival in Ariège, investigations were conducted by the Midi-Pyrénées Regional Health Agency (Cire) and the Ariège Departmental Health Agency (ARS DT) to confirm the presence of an AGE-type outbreak and characterize it, identify the pathogen responsible for the illness and the mode(s) of transmission within the community, and trace the source of contamination that caused the outbreak. Given the initial findings of the investigation at the time of the report, which indicated cases of GEA only among festival volunteers (no cases of the disease reported among festival-goers), the epidemiological and microbiological investigations focused on the volunteers and were conducted using questionnaires. As of July 26, there were 70 cases (preliminary results) among nearly 300 volunteers, with symptoms appearing between July 18 and 24, peaking at 35 cases on July 21. The main symptoms reported are diarrhea, abdominal pain, fever, and nausea. Of the 70 cases recorded to date, 9 have recovered (with the illness lasting 3 to 4 days in these individuals) and 4 were hospitalized without signs of severe illness. Stool analyses conducted on several patients identified the bacterium Shigella Sonnei, which showed no particular antibiotic resistance profile. Waterborne transmission has been ruled out, and the possible transmission routes currently under investigation are potentially cumulative: food contamination through food handling by carriers; person-to-person transmission; and possibly environmental transmission.The reservoir for Shigella Sonnei is exclusively human, with a high potential for contamination, particularly through person-to-person contact, as shedding can continue for several days after symptoms have subsided. Strict hygiene measures are therefore necessary to prevent secondary infections. To date, further spread of the outbreak within the region remains possible.