title: Outbreak of influenza A (H3N2) variant virus infection among attendees of an agricultural fair, Pennsylvania, USA, 2011.
abstract: During August 2011, influenza A (H3N2) variant [A(H3N2)v] virus infection developed in a child who attended an agricultural fair in Pennsylvania, USA; the virus resulted from reassortment of a swine influenza virus with influenza A(H1N1)pdm09. We interviewed fair attendees and conducted a retrospective cohort study among members of an agricultural club who attended the fair. Probable and confirmed cases of A(H3N2)v virus infection were defined by serology and genomic sequencing results, respectively. We identified 82 suspected, 4 probable, and 3 confirmed case-patients who attended the fair. Among 127 cohort study members, the risk for suspected case status increased as swine exposure increased from none (4%; referent) to visiting swine exhibits (8%; relative risk 2.1; 95% CI 0.2-53.4) to touching swine (16%; relative risk 4.4; 95% CI 0.8-116.3). Fairs may be venues for zoonotic transmission of viruses with epidemic potential; thus, health officials should investigate respiratory illness outbreaks associated with agricultural events.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia 30329, USA. kwong@cdc.gov
authors.forename: Karen K
authors.initials: KK
authors.lastname: Wong
authors.forename: Adena
authors.initials: A
authors.lastname: Greenbaum
authors.forename: Maria E
authors.initials: ME
authors.lastname: Moll
authors.forename: James
authors.initials: J
authors.lastname: Lando
authors.forename: Erin L
authors.initials: EL
authors.lastname: Moore
authors.forename: Rahul
authors.initials: R
authors.lastname: Ganatra
authors.forename: Matthew
authors.initials: M
authors.lastname: Biggerstaff
authors.forename: Eugene
authors.initials: E
authors.lastname: Lam
authors.forename: Erica E
authors.initials: EE
authors.lastname: Smith
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Storms
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Miller
authors.forename: Virginia
authors.initials: V
authors.lastname: Dato
authors.forename: Kumar
authors.initials: K
authors.lastname: Nalluswami
authors.forename: Atmaram
authors.initials: A
authors.lastname: Nambiar
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Silvestri
authors.forename: James R
authors.initials: JR
authors.lastname: Lute
authors.forename: Stephen
authors.initials: S
authors.lastname: Ostroff
authors.forename: Kathy
authors.initials: K
authors.lastname: Hancock
authors.forename: Alicia
authors.initials: A
authors.lastname: Branch
authors.forename: Susan C
authors.initials: SC
authors.lastname: Trock
authors.forename: Alexander
authors.initials: A
authors.lastname: Klimov
authors.forename: Bo
authors.initials: B
authors.lastname: Shu
authors.forename: Lynnette
authors.initials: L
authors.lastname: Brammer
authors.forename: Scott
authors.initials: S
authors.lastname: Epperson
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
authors.forename: Michael A
authors.initials: MA
authors.lastname: Jhung
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007223:Infant; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D010414:Pennsylvania / Q000453:epidemiology; D012189:Retrospective Studies; D013552:Swine; D055815:Young Adult