Caused by the influenza virus (CIV). 2 strains have been indentified. H3N8 was the first strain seen in the racing greyhounds in Florida in 2004. H3N2 is the newest strain identified last year in Chicago.
CIV is highly contagious and easily spread from the infected dog through direct contact; nasal secretions by barking/sneezing/coughing; and objects such as bowls and kennel surfaces. It can also be spread by people moving from an infected to unaffected dog without taking precautionary measures of disinfection. The virus can remain alive (and able to infect) on surfaces for up to 48hrs, on clothing for 24hrs and on hands for 12hrs.
CIV closely resembles kennel cough. The illness may be mild or severe with a developing persistent cough, nasal discharge, fever, lethargy, low appetite or eye discharge. Some dogs may show no symptoms but still shed the virus.
Incubation is 2-4 days. This is the most contagious period - when they are infected and shedding the virus but not yet showing signs of illness. Shedding can continue up to 7-10 days. Most dogs recover within 2-3 weeks. But secondary bacterial infections can develop which can cause other illnesses such as pneumonia.
CIV cannot be diagnosed solely by clinical symptoms because the signs are similar to Kennel Cough and other respiratory illnesses. There is an accurate lab test that requires 2 blood samples. One sample is taken during the first week of illness; and the other sample is taken 10-14 days later. Another test (PCR test) can be done at 3 days with a nasal swab, but there can be false negatives with this test if not taken at the peak time of viral shedding.
As with all viral infections, treatment is mostly just supportive, with good nutrition and care at home. Your vet may give cough suppressants to help relieve the cough. If symptoms are more than mild and your vet suspects a secondary bacterial infection, they may prescribe antibiotics and/or IV fluids.
Yes there is a vaccine for both strains. Missoula Vet Clinic carries the newest strain (H3N2). It requires 2 shots each 3-4 weeks apart and then due annually after that. This is not considered to be part of the "core" vaccines we usually give dogs. It is intended for those dogs who are at high risk for exposure such as going to doggie daycare, kennel boarding often, dog shows, etc. The best thing is to discuss these risk factors with your vet and decide together whether it is prudent to vaccinate.