Commentary: Coughing dogs at your clinic? Consider canine flu
No veterinarian likes to hear about anything unexplained. We do not like medical mysteries. We like cold, hard facts, because then we can make a plan to address or head off the issue. By nature, we seek answers and are dissatisfied with ambiguity.
In late July in the Bozeman, Montana, area, Jarrod Moss, DVM, started seeing coughing dogs—a lot of coughing dogs. In fact, his three animal hospitals were seeing three to four cases every day. What’s more, these coughing dogs seemed to be developing acute respiratory distress. Dr. Moss estimates that over the course of a few weeks, his three hospitals treated 15 to 20 cases of pneumonia, which in his experience is almost unheard of.
All of the dogs treated in his hospitals recovered from the cough and secondary issues, but others in the area were not so lucky. He heard reports of dogs dying from the pneumonia that seemed to follow the onset of acute cough. By early September, the numbers had started to drop off, from three to four cases per day to three to four per week.
Dr. Moss says that when he first started seeing the cases, something didn’t seem right. The problem seemed so contagious. He said one dog’s infection in particular could be traced to a doggie daycare facility. He suspected canine influenza virus (CIV), so he submitted patient samples to the Animal Health Diagnostic Center at Cornell University. The lab performed a hemagglutination inhibition antibody titer (HI) on serum. This type of test is based on the highest dilution of serum that prevents the agglutination of red blood cells by CIV but does not isolate the virus itself.
Because the testing is fairly expensive, Dr. Moss absorbed the cost—he wanted to get to the bottom of what was going on. The lab says that for HI antibody titers to be considered meaningful, there should be a fourfold difference between paired samples run on the same day. The first serum sample Dr. Moss submitted suggested “acute phase of infection or a non-specific reaction,” but the second sample for the same patient was markedly increased, which is consistent with exposure to CIV. The lab would not officially confirm CIV without additional testing to isolate the virus. But Dr. Moss thought he had his answer. He had suspected CIV all along, and these results were enough for him. He reached out to other veterinarians in his area to make them aware of the findings.
Dr. Moss says his area is rural and not many of the surrounding hospitals recommend vaccinating dogs for CIV, but he thinks they should consider it. The vaccine is something we veterinarians have in our arsenal to combat a disease that has sickened hundreds—if not thousands—of dogs. If any veterinarian sees a dog for acute cough, especially if the dog is young and social, CIV should be considered a rule-out.
At this time, the only treatment for CIV infection is supportive care and careful observation for secondary issues. As veterinarians, we should be submitting samples for testing so we can monitor the progress of CIV nationwide.