DOG FLU H3N2 NEWS REPORT UPDATE
Animal Bond Radio Program Interview
Report Data: Cornell University of School Veterinary Medicine
The AHDC has been involved in the identification of canine influenza virus (CIV) as the cause of a widespread outbreak of acute respiratory disease in the Chicago area. While other potential pathogens have been detected in some animals, the most frequent agent has been CIV. CIV was first identified as a factor in canine respiratory disease in 2004. The virus circulating in the US is a genetic variant of the H3N8 equine influenza virus. The key change in the virus was the ability for transmission of the virus from dog to dog. Virtually all dogs are susceptible to infection regardless of age or breed. In the intervening years, it has been the case that CIV is an infection that is initiated by close contact with an infected dog in a restricted space such as an animal shelter, day care center, or boarding kennel. Casual contact is less likely to be a factor mainly due to the relatively low amount of virus being shed by an infected dog. As is the case with all influenza viruses, there is the opportunity for changes in the virus that could affect transmission rates. It is for this reason that the AHDC continues to track these changes and determine whether new variants are more virulent.
Influenza virus infection in dogs follows a similar pattern to infections in other species. The onset of clinical signs will be 2-3 days post infection. Peak of virus shed is 3-4 days post infection and the presence of infectious virus declines rapidly with the onset of an immune response. Dogs coughing for > 10days are not infectious as the cough is due to damage to the respiratory tract epithelium. While in the past CIV infections in and of themselves have not shown a significant mortality rate, CIV infections as well as other respiratory viruses compromise the normal defenses of the lung permitting secondary bacterial pneumonias.
SAMPLING and SHIPPING INFORMATION
As with all respiratory viruses, it is critical to take samples for agent detection within a day or two of the onset of clinical signs which include runny nose, low grade fevers, and coughing. It is very uncommon, but this virus can be fatal in some dogs. Dogs showing clinical signs for >7 days should be tested for CIV by an antibody test as the virus itself will be undetectable in most cases. For rRT-PCR (real time PCR) or virus isolation, nasal or pharyngeal swabs are the samples of choice. Do not place swabs in bacterial transport media unless you are attempting to isolate a bacterial or mycoplasma infection. To detect viruses, swabs can be placed into a red-top blood collection tube with a few drops of sterile saline or viral transport media if available. If any animal should die from suspected influenza fresh lung tissue is the tissue of choice.
Samples should be shipped on packs and arrive chilled using a next day delivery. Check our website or this link
for on line ordering of shipping labels. The AHDC offers a canine respiratory PCR panel. This panel includes canine adenovirus, canine distemper virus, canine parainfluenza virus, canine respiratory coronavirus, canine pneumovirus, Bordetella bronchiseptica, and Mycoplasma cynos along with matrix influenza PCR. It is difficult to determine solely by clinical signs which respiratory pathogen is present in the dog; the respiratory panel is the best option. It is common to find multiple viruses in these environments and this panel will assist in finding those agents.
SAMPLING LATER IN COURSE OF DISEASE
Testing for antibodies specific for the H3N8 influenza virus is generally done using the standard influenza virus test of hemagglutination inhibition (HI). Antibodies to CIV develop rapidly and by 10 days post infection there is a significant antibody titer. In the absence of a history of vaccination, the presence of CIV antibodies following a clinical illness is highly correlated with CIV being part of the clinical event.
The ADHC at Cornell has developed a serologic assay that detects antibodies to the newly identified H3N2 influenza virus. Veterinarians and pet owners should submit acute and convalescent serum samples and request influenza HAI. Samples from dogs with respiratory disease will be tested for both H3N8 and H3N2-specific antibodies. Results will be provided for both assays for the same cost as the original H3N8 assay.
Vaccines do exist for CIV. Both of the products offered are killed vaccines and two doses of the vaccines are necessary to develop an effective immune response. While the vaccines may not prevent an infection, they do reduce shed of the virus and the severity of clinical disease.
Additional information can be found on the CDC website (http://www.cdc.gov/flu/canine/ ) or contact the AHDC at Cornell University at 607.253.3900.
CDC canine flu fact sheet http://www.cdc.gov/flu/canine/index.htm.
CDC spotlight on the outbreak http://www.cdc.gov/flu/news/canine-influenza-update.htm.
BREAKING NEWS: Data provided to the Animal Bond Radio News Bureau by Cornell University School of Veterinary Medicine
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