Influenza A virus (H3N8) in dogs with respiratory disease, Florida

• Published in: Emerging infectious diseases 2008-06, Vol.14 (6), p.902-908
• Main Authors: Payungporn, Sunchai, Crawford, P Cynda, Kouo, Theodore S, Chen, Li-mei, Pompey, Justine, Castleman, William L, Dubovi, Edward J, Katz, Jacqueline M, Donis, Ruben O
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; canine influenza; Causes of; Diagnosis; Disease Outbreaks; Dog Diseases - epidemiology; Dog Diseases - mortality; Dog Diseases - virology; Dogs; Florida; Florida - epidemiology; Genetic aspects; Hemagglutination Inhibition Tests; hemagglutinin gene sequence; Identification and classification; Influenza A virus; Influenza A Virus, H3N8 Subtype - classification; Influenza A Virus, H3N8 Subtype - genetics; Influenza A Virus, H3N8 Subtype - isolation & purification; Influenza type A virus; Influenza viruses; molecular phylogeny; Molecular Sequence Data; Nucleotide sequence; Orthomyxoviridae Infections - epidemiology; Orthomyxoviridae Infections - mortality; Orthomyxoviridae Infections - veterinary; Orthomyxoviridae Infections - virology; Phylogeny; Physiological aspects; Pneumonia, Viral - epidemiology; Pneumonia, Viral - mortality; Pneumonia, Viral - veterinary; Pneumonia, Viral - virology; Respiratory tract diseases; Respiratory Tract Infections - epidemiology; Respiratory Tract Infections - mortality; Respiratory Tract Infections - veterinary; Respiratory Tract Infections - virology; Sequence Analysis, DNA
• ISSN: 1080-6040; 1080-6059
• DOI: 10.3201/eid1406.071270

In 2004, canine influenza virus subtype H3N8 emerged in greyhounds in the United States. Subsequent serologic evidence indicated virus circulation in dog breeds other than greyhounds, but the virus had not been isolated from affected animals. In 2005, we conducted virologic investigation of 7 nongreyhound dogs that died from respiratory disease in Florida and isolated influenza subtype H3N8 virus. Antigenic and genetic analysis of A/canine/Jacksonville/2005 (H3N8) and A/canine/Miami/2005 (H3N8) found similarity to earlier isolates from greyhounds, which indicates that canine influenza viruses are not restricted to greyhounds. The hemagglutinin contained 5 conserved amino acid differences that distinguish canine from equine lineages. The antigenic homogeneity of the canine viruses suggests that measurable antigenic drift has not yet occurred. Continued surveillance and antigenic analyses should monitor possible emergence of antigenic variants of canine influenza virus.