title: Seroprevalence and risk factors for canine H3N8 influenza virus exposure in household dogs in Colorado.
abstract: BACKGROUND
  Since 2004, canine influenza virus (CIV) has spread throughout the United States. While studies suggest that CIV is commonly detected in shelter dogs, little is known about its prevalence in household dogs.
  
  
  OBJECTIVE
  To evaluate the seroprevalence of CIV in pet dogs presented for care in a veterinary hospital in Colorado and to investigate risk factors that might predispose these dogs to CIV infection.
  
  
  METHODS
  One hundred and forty dogs presenting to the Community Practice service, 110 dogs seen at other clinical services at Colorado State University's Veterinary Teaching Hospital in 2009, and samples from 75 dogs seen before 2004.
  
  
  METHODS
  In this prospective study, samples were tested with hemagglutination inhibition assays, using 3 CIV isolates. To identify risk factors for CIV infection, 140 owners completed questionnaires at time of sampling.
  
  
  RESULTS
  CIV seroprevalence was 2.9% (4/140) for dogs seen by the Community Practice service and 4.5% (5/110) for dogs seen by other hospital services (P=.48). All sera collected before 2004 tested negative for CIV. No differences were seen in antibody titers to the 3 CIV isolates tested. Data from the questionnaires indicated an association between CIV seropositivity and canine daycare visits (P<.001).
  
  
  CONCLUSIONS
  CIV seropositivity in household dogs in Colorado is low, although it has increased since 2004. Antibody titers to the 3 CIV isolates were comparable, suggesting that measurable antigenic drift has not yet occurred. Finally, dogs boarded in kennels or attending daycare might be at an increased risk of CIV infection.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Science, Colorado State University, Fort Collins, CO 80523-1678, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Barrell
authors.forename: H L
authors.initials: HL
authors.lastname: Pecoraro
authors.forename: C
authors.initials: C
authors.lastname: Torres-Henderson
authors.forename: P S
authors.initials: PS
authors.lastname: Morley
authors.forename: K F
authors.initials: KF
authors.lastname: Lunn
authors.forename: G A
authors.initials: GA
authors.lastname: Landolt
mesh_terms: D000818:Animals; D003120:Colorado / Q000453:epidemiology; D004283:Dog Diseases / Q000453:epidemiology / Q000821:virology*; D004285:Dogs; D005260:Female; D053123:Influenza A Virus, H3N8 Subtype / Q000302:isolation & purification*; D008297:Male; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D012307:Risk Factors; D016036:Seroepidemiologic Studies