The time the virus takes to travel from the wound to the brain and for the disease to develop varies. This is called the incubation period. It will be shorter if the injury is near the head. For a dog, the incubation period generally lasts about 2 months. But it can be as short as 2 weeks and sometimes as long as 6 months.

A dog that starts to show symptoms of the disease will die within a few days. If a dog has been sick for more than 10 days, it is not rabies.

On another hand, if a dog bites someone, that doesn’t mean the dog has been infected with rabies or that he is contagious. This is why we are asked to keep the pet in observation and alive for a period of 10 days. A dog with the virus in its salivary glands, which implies that its brain is already contaminated, will quickly show signs of the disease. 

If an animal is still healthy 10 days after biting, we can be sure that it could not have had any virus in its saliva when it bit.  It could not therefore have transmitted rabies. But it may still be incubating it.  That is why we start a 10-day observation period after any bite.

If a vaccine is given to a dog that was infected more than 7 days previously, the vaccine cannot prevent the development of the disease. The virus is hidden in the nerves, well protected. This means that only 6 months after the first dose can we say that the dog is vaccinated and free of rabies.