Carrie Ambrose, age 11, of Carson City, Nev., for her question:     

WHAT CAUSES DISTEMPER?

Distemper is a disease of dogs. In some ways it is like influenza in human beings. It strikes dogs between the ages of 2 months and 1 year most of the time,  although it can happen in older dogs.

Primary cause of distemper is a virus, complicated by secondary bacterial infections.

Distemper is contagious. The first symptoms include shivering, sneezing, a rise in temperature and discharges from the nose and mouth. The disease often brings death.

Veterinarians recommend annual vaccination of all young dogs except pregnant females as a way to prevent attacks of distemper. In 1954 several new strains of distemper virus were discovered and doctors now suggest that the vaccines should be modified from time to time.

No known medicines will cure distemper.