Patrick K. Mitchell
An investigation of an outbreak of acute gastrointestinal illness among attendees of three outdoor festivals in Pennsylvania last year revealed that the primary source of drinking water was contaminated with norovirus and other fecal microbes. Investigators’ recommendations, like improving access to clean drinking water and adequate sanitation, may have prevented another outbreak from occurring during a fourth festival at the same venue.
On June 13, 2017, the Pennsylvania Department of Health was notified of an outbreak of acute gastrointestinal illness (AGI) among attendees of a festival at an unnamed venue. Additional cases were reported from two more festivals at the same venue, held May 31 to June 18. Patrick K. Mitchell, ScD, a CDC Epidemic Intelligence Service officer assigned to the state health department, and colleagues searched social media pages associated with both the venue and the festivals to identify attendees who became ill, some of whom submitted stool and vomitus specimens for testing.
“There was a lot of conversation on social media about the outbreaks on different Facebook pages for the events and the venue, so we put together a brief message and asked the page administrators to 'sticky' it so it would be at the top whenever people visited the page,” Mitchell told Infectious Disease News. “Our message often got merged with longer posts from the venue or event organizers describing the joint efforts to respond to the outbreaks.”
The investigators also analyzed environmental samples from the venue — including those collected from a nearby well, creek and ground water.
The CDC estimates that 179 million episodes of AGI occur annually in the United States, with norovirus being the most common cause. The primary mode of transmission during AGI outbreaks — if it is known — is through person-to-person contact and environmental contamination.
According to Mitchell and colleagues, 179 self-reports of AGI were associated with the three outdoor Pennsylvania festivals. Norovirus was detected in seven of eight samples from attendees who reported being ill. The investigators also found norovirus and other fecal microbes in both creek and well water samples collected at the venue, and they suspected that a septic leach field was the source of the outbreak. Based on the investigators’ recommendations, the venue accelerated plans to install a new well located farther from the septic leach field, and they increased the number of portable toilets and hand-washing stations. In addition, they promoted proper hand hygiene during the fourth festival. Active surveillance during this festival identified five ill persons — one of whom submitted a stool specimen that tested negative for norovirus and other enteric pathogens. No outbreak occurred during the event, investigators said, underscoring the importance of these types of interventions to prevent AGI.
“It is difficult to know the exact reason why an outbreak does not occur at any particular event, but access to clean water and good hand hygiene practices are key to preventing these types of outbreaks,” Mitchell said. “In addition, it is important that event organizers have adequate facilities for the number of attendees.” – by John Schoen
Mitchell PK, et al. Gastrointestinal illness outbreak at multiple outdoor festivals — Pennsylvania, 2017. Presented at: Epidemic Intelligence Service conference; April 16-19, 2018; Atlanta.
Wikswo ME, et al. MMWR Surveill Summ. 2015;doi:10.15585/mmwr.mm6412a1.
Disclosures: The authors report no relevant financial disclosures.