Blood de Brad Anderson

Jess, a recently separated nurse, moves back into her old family farmhouse with Tyler, her teenage daughter, and Owen, her eight-year-old son. One night, the family dog spots something in the woods and heads out to look for it. When he returns home, he attacks Owen, savagely biting him. The boy is rushed to the hospital. His condition only grows worse, and no one can understand why, until Jess discovers an unsettling cure.