title: The potential impact of media reporting in syndromic surveillance: an example using a possible Cryptosporidium exposure in North West England, August to September 2015.
abstract: During August 2015, a boil water notice (BWN) was issued across parts of North West England following the detection of Cryptosporidium oocysts in the public water supply. Using prospective syndromic surveillance, we detected statistically significant increases in the presentation of cases of gastroenteritis and diarrhoea to general practitioner services and related calls to the national health telephone advice service in those areas affected by the BWN. In the affected areas, average in-hours general practitioner consultations for gastroenteritis increased by 24.8% (from 13.49 to 16.84) during the BWN period; average diarrhoea consultations increased by 28.5% (from 8.33 to 10.71). Local public health investigations revealed no laboratory reported cases confirmed as being associated with the water supply. These findings suggest that the increases reported by syndromic surveillance of cases of gastroenteritis and diarrhoea likely resulted from changes in healthcare seeking behaviour driven by the intense local and national media coverage of the potential health risks during the event. This study has further highlighted the potential for media-driven bias in syndromic surveillance, and the challenges in disentangling true increases in community infection from those driven by media reporting.
authors.affiliation: Public Health England, Birmingham, United Kingdom.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Elliot
authors.forename: Helen E
authors.initials: HE
authors.lastname: Hughes
authors.forename: John
authors.initials: J
authors.lastname: Astbury
authors.forename: Grainne
authors.initials: G
authors.lastname: Nixon
authors.forename: Kate
authors.initials: K
authors.lastname: Brierley
authors.forename: Roberto
authors.initials: R
authors.lastname: Vivancos
authors.forename: Thomas
authors.initials: T
authors.lastname: Inns
authors.forename: Valerie
authors.initials: V
authors.lastname: Decraene
authors.forename: Katherine
authors.initials: K
authors.lastname: Platt
authors.forename: Iain
authors.initials: I
authors.lastname: Lake
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: O'Brien
authors.forename: Gillian E
authors.initials: GE
authors.lastname: Smith
mesh_terms: D000818:Animals; D003457:Cryptosporidiosis / Q000175:diagnosis / Q000453:epidemiology*; D003458:Cryptosporidium; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D018563:Disease Notification; D004196:Disease Outbreaks; D004739:England / Q000453:epidemiology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology / Q000382:microbiology; D006266:Health Education; D006801:Humans; D008402:Mass Media; D011159:Population Surveillance / Q000379:methods*; D011446:Prospective Studies; D014871:Water Microbiology; D014881:Water Supply
keywords: Cryptosporidium; bias; diarrhoea; gastroenteritis; media; syndromic surveillance