title: Evaluation of infectivity of a canine lineage H3N8 influenza A virus in ponies and in primary equine respiratory epithelial cells.
abstract: OBJECTIVE
  To evaluate whether an equine-derived canine H3N8 influenza A virus was capable of infecting and transmitting disease to ponies.
  
  
  METHODS
  20 influenza virus-seronegative 12- to 24-month-old ponies.
  
  
  METHODS
  5 ponies were inoculated via aerosol exposure with 10(7) TCID(50) of A/Canine/Wyoming/86033/07 virus (Ca/WY)/pony. A second group of 5 ponies (positive control group) was inoculated via aerosol exposure with a contemporary A/Eq/Colorado/10/07 virus (Eq/CO), and 4 sham-inoculated ponies served as a negative control group. To evaluate the potential for virus transmission, ponies (3/inoculation group) were introduced 2 days after aerosol exposure and housed with Ca/WY- and Eq/CO-inoculated ponies to serve as sentinel animals. Clinical signs, nasal virus shedding, and serologic responses to inoculation were monitored in all ponies for up to 21 days after viral inoculation. Growth and infection characteristics of viruses were examined by use of Madin-Darby canine kidney cells and primary equine and canine respiratory epithelial cells.
  
  
  RESULTS
  Ponies inoculated with Ca/WY had mild changes in clinical appearance, compared with results for Eq/CO-inoculated ponies. Additionally, Ca/WY inoculation induced significantly lower numbers for copies of the matrix gene in nasal secretions and lower systemic antibody responses in ponies than did Eq/CO inoculation. The Ca/WY isolate was not transmitted to sentinel ponies.
  
  
  CONCLUSIONS
  Inoculation of ponies with the canine H3N8 isolate resulted in mild clinical disease, minimal nasal virus shedding, and weak systemic antibody responses, compared with responses after inoculation with the equine H3N8 influenza isolate. These results suggested that Ca/WY has not maintained infectivity for ponies.
authors.affiliation: Department of Microbiology, College of Veterinary Medicine and Biological Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Ayshea M
authors.initials: AM
authors.lastname: Quintana
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Hussey
authors.forename: Ema C
authors.initials: EC
authors.lastname: Burr
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Pecoraro
authors.forename: Kristina M
authors.initials: KM
authors.lastname: Annis
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Rao
authors.forename: Gabriele A
authors.initials: GA
authors.lastname: Landolt
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000917:Antibody Formation; D002478:Cells, Cultured; D004283:Dog Diseases / Q000473:pathology / Q000635:transmission / Q000821:virology; D004285:Dogs; D004847:Epithelial Cells / Q000821:virology*; D006734:Horse Diseases / Q000473:pathology / Q000635:transmission / Q000821:virology*; D006736:Horses; D053123:Influenza A Virus, H3N8 Subtype / Q000302:isolation & purification / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D011897:Random Allocation; D014132:Trachea / Q000166:cytology / Q000821:virology*; D017201:Virus Shedding
chemical_list: D000914:Antibodies, Viral