Distemper is a very serious disease caused by a virus. The first symptoms are those of a bad cold: coughing, sneezing, runny nose and eyes. In about half the cases, the disease then travels to the brain, where it can cause seizures and other problems with the nervous systems. It is often fatal, killing almost all the dogs that develop seizures and others by weakening them to the point where they develop pneumonia. Even dogs that survive distemper frequently suffer brain damage. There is no cure, so prevention is the key. Puppies between six and eighteen weeks old should receive shots every three weeks, then a booster each year. Distemper has been declining in this country for many years, but there are still outbreaks in cities with a large population of strays.