title: Prevalence of and exposure factors for seropositivity to H3N8 canine influenza virus in dogs with influenza-like illness in the United States.
abstract: OBJECTIVE
  To estimate the seroprevalence of antibodies against H3N8 canine influenza virus (CIV) in a population of US dogs with influenza-like illness (ILI) and to identify factors associated with seropositivity.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  1,268 pet and shelter dogs with ILI in 42 states.
  
  
  METHODS
  Serum samples collected from dogs from 2005 through June 2009 were tested for H3N8 CIV antibodies with a hemagglutination inhibition assay. Intrinsic factors (age, breed, and sex), extrinsic factors (dogs housed in a shelter facility, boarding kennel, or other setting), and geographic region (southwest, west, Midwest, southeast, and northeast) were compared between seropositive and seronegative dogs to identify variables associated with seropositivity.
  
  
  RESULTS
  Most (750/1,268 [59%]) dogs in the study were from Colorado, Florida, or New York. The overall seroprevalence of antibodies against H3N8 CIV was 49% (618/1,268 dogs; 95% confidence interval, 46% to 51%). The annual prevalence of H3N8 CIV seropositivity increased from 2005 (44%) to 2006 (53%) and 2007 (62%), then decreased in 2008 (38%) and 2009 (15%). The likelihood of H3N8 CIV seropositivity was associated with geographic region (southeast during 2005, west and northeast during 2006 and 2007, and northeast during 2008) and exposure setting (dogs housed in a shelter facility or boarding kennel during 2005 and 2006).
  
  
  CONCLUSIONS
  Results of this study suggested there is a need for continued surveillance for H3N8 CIV infection in dogs in the United States and that personnel in communal dog-housing facilities should formulate, implement, and evaluate biosecurity protocols to reduce the risk of CIV transmission among dogs.
authors.affiliation: Maddie's Shelter Medicine Program, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Tara C
authors.initials: TC
authors.lastname: Anderson
authors.forename: P Cynda
authors.initials: PC
authors.lastname: Crawford
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Dubovi
authors.forename: E Paul J
authors.initials: EP
authors.lastname: Gibbs
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Hernandez
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D003430:Cross-Sectional Studies; D003710:Demography; D004283:Dog Diseases / Q000453:epidemiology / Q000821:virology*; D004285:Dogs; D005260:Female; D006799:Housing, Animal; 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; D013997:Time Factors; D014481:United States / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral