Cujo by Stephen King

Cujo is a horror novel by Stephen King published in 1981.  It was made into a movie of the same name in 1983.

Cujo is a rabid St. Bernard that terrorizes Donna Trenton and her four-year-old son Tad in the fictional town of Castle Rock, Maine.

The novel intersperses passages about the mundane lives of the town’s residents with the story of Cujo.

Cujo has never been vaccinated against rabies by his owner, Joe Camber. The dog gets rabies when he gets his head stuck in the entrance to a limestone cave while chasing a rabbit and gets bitten by a rabid bat.

Soon thereafter, Cujo develops rabies and attacks Cambers’ neighbor and when Joe Camber goes to check on the neighbor, Cujo kills him as well.