title: Evidence of transmission and risk factors for influenza A virus in household dogs and their owners.
abstract: BACKGROUND
  The possible transmission of influenza A virus between dogs and humans is important, as in Mexico City there are approximately 1·2 million dogs. We present the first evidence of influenza A virus infection in household dogs in Mexico.
  
  
  OBJECTIVE
  The objective of this study was to identify the presence of antibodies against influenza A virus in dogs and their owners, as well as the presence of RNA of influenza A virus in nasal exudates of dogs and, thereby, assess the possible transmission of the virus between humans and dogs.
  
  
  METHODS
  Serum samples from household dogs and their owners were analyzed to detect the presence of antibodies against three subtypes of human influenza virus (H1N1pdm09, H1N1, and H3N2), as well as subtype H3N8 of equine influenza. We analyzed dog nasal exudates to detect influenza viral RNA. The relationship between the seropositivity of dogs and various factors (age, sex, constantly at home, and seropositivity of owners) was statistically analyzed.
  
  
  RESULTS
  Seroprevalence for human influenza in dogs was 0·9% (1 of 113), and it was 4% (5 of 113) for equine influenza. In humans, seroprevalence was 22% for subtype H1N1pdm09, 20% for subtype H1N1, and 11% for subtype H3N2. No significant association (P>0·05) was found between seropositivity and any of the assessed factors. Furthermore, no viral RNA was detected in the nasal exudate samples.
  
  
  CONCLUSIONS
  Results revealed seroprevalence of the influenza virus in household dogs in Mexico City. It can be assumed that dogs are currently becoming infected with different subtypes of influenza viruses.
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Distrito Federal, México.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Ramírez-Martínez
authors.forename: María
authors.initials: M
authors.lastname: Contreras-Luna
authors.forename: Jazmín
authors.initials: J
authors.lastname: De la Luz
authors.forename: María E
authors.initials: ME
authors.lastname: Manjarrez
authors.forename: Dora P
authors.initials: DP
authors.lastname: Rosete
authors.forename: José F
authors.initials: JF
authors.lastname: Rivera-Benitez
authors.forename: Manuel
authors.initials: M
authors.lastname: Saavedra-Montañez
authors.forename: Humberto
authors.initials: H
authors.lastname: Ramírez-Mendoza
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D012634:Bodily Secretions / Q000821:virology; D004283:Dog Diseases / Q000821:virology*; D004285:Dogs; D005191:Family Characteristics; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000635:transmission* / Q000821:virology; D008297:Male; D008800:Mexico; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral
keywords: Canine influenza; cross-species transmission; human influenza; risk factors
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