Kennel cough is passed similarly to a human cold by contact and through fluids from the dog coughing or sneezing.
Its called kennel cough as its so easily passed around in the stressful situation of being kenneled.
Symptoms begin usually 3 to 5 days after exposure.
You can read about this virus here and the other viruses that often show up along wtih it
Dogs can shed the bordatella bacteria for up to three months after they were infected.
Hope this helps you!