By now you likely have heard of the massive outbreak of Canine Influenza Virus (CIV) in Chicago. Signs of CIV can include persistent cough, runny nose, sneezing, fever, lethargy and loss of appetite. Most dogs have a mild form with a cough persisting for 10 to 21 days in spite of treatment with antibiotics and cough suppressants. Some dogs develop mucoid nasal discharge due to secondary bacterial infection, while others can be seriously ill with fever and pneumonia. Other diseases can result in similar signs, including “kennel cough,” which is caused by one or more bacterial and viral infections such as Bordetella and Parainfluenza. If you dog is experiencing signs of disease, please contact your veterinarian for diagnosis and treatment. CIV is highly contagious and easily spread through contact, coughing and sneezing, on contaminated surfaces including food and water bowls and collars and leashes, or by people moving between infected and non-infected dogs. Incubation is 2 to 4 days from exposure to onset of clinical signs. Infected dogs are most contagious during incubation before they get sick, and continue to spread the virus for 7 to 10 days. Because this is a new virus, all dogs – all breeds and ages – are susceptible and none have natural immunity. Of exposed dogs, approximately 80% will get sick, but the other 20% still are capable of spreading the disease. This is not a seasonal flu like the human form can be, but can strike at any time. There is no evidence that people can catch CIV but it appears that some strains can affect cats. CIV is diagnosed by a nasal or throat swab during the first 4 days of disease, or more accurately by blood antibody titers with two samples taken 10-14 days apart. CIV was first diagnosed in 2004 in racing greyhounds in Florida. Similar outbreaks have been documented in 30 states and are most common in Florida, New York, Pennsylvania and Colorado. These outbreaks of CIV were caused by the H3N8 strain of influenza virus and a vaccine was developed to protect dogs against infection. Immunization requires two vaccines given 3 to 4 weeks apart, with immunity developing 10-14 days after the second injection. Annual booster vaccines are required. However, the current outbreak is caused by a new strain of CIV, H3N2 rather than H3N8. The new strain was seen previously only in China and South Korea. While we don’t know how the current outbreak in Chicago originated, a dog imported from one of those countries may have been responsible. The current outbreak mainly affects the city of Chicago, with additional cases reported form the closer-in suburbs, including Deerfield, as well as Wisconsin and Indiana. It is unknown whether the current CIV vaccination for the H3N8 virus offers any protection against the new H3N2 virus. The CIV vaccine may not prevent illness caused by the new strain altogether, but it appears to lessen the severity and duration of the disease, and it’s the only CIV vaccine available. The best way to prevent your dog from getting sick is to avoid places dogs gather, such as dog parks, doggy day care, grooming parlors, and boarding kennels until this outbreak subsides. If your dog must go to such places, consider getting both Bordetella and CIV vaccinations. Please contact your veterinarian for specific advice about prevention and treatment of Canine Influenza Virus.
Steve Barten, DVM
Vernon Hills Animal Hospita
847-367-4070
vhah.com
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