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Veterinary Medicine International
Volume 2013 (2013), Article ID 874521, 10 pages
http://dx.doi.org/10.1155/2013/874521
Research Article

Comparison of the Infectivity and Transmission of Contemporary Canine and Equine H3N8 Influenza Viruses in Dogs

1Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biological Sciences, Colorado State University, 300 West Drake Road, Campus Delivery 1678, Fort Collins, CO 80523, USA
2Department of Clinical Sciences, College of Veterinary Medicine and Biological Sciences, Colorado State University, 300 West Drake Road, Campus Delivery 1678, Fort Collins, CO 80523, USA

Received 3 June 2013; Revised 18 August 2013; Accepted 26 August 2013

Academic Editor: Timm C. Harder

Copyright © 2013 Heidi L. Pecoraro et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Phylogenetic analyses indicate that canine influenza viruses (CIVs) (H3N8) evolved from contemporary equine influenza virus (EIV). Despite the genetic relatedness of EIV and CIV, recent evidence suggests that CIV is unable to infect, replicate, and spread among susceptible horses. To determine whether equine H3N8 viruses have equally lost the ability to infect, cause disease, and spread among dogs, we evaluated the infectivity and transmissibility of a recent Florida sublineage EIV isolate in dogs. Clinical signs, nasal virus shedding, and serological responses were monitored in dogs for 21 days after inoculation. Real-time reverse transcription-PCR and hemagglutination inhibition assays showed that both the viruses have maintained the ability to infect and replicate in dogs and result in seroconversion. Transmission of EIV from infected to sentinel dogs, however, was restricted. Furthermore, both CIV and EIV exhibited similar sialic acid-α2,3-gal receptor-binding preferences upon solid-phase binding assays. The results of the in vivo experiments reported here suggesting that dogs are susceptible to EIV and previous reports by members of our laboratory showing limited CIV infection in horses have been mirrored in CIV and EIV infections studies in primary canine and equine respiratory epithelial cells.