Diff'rent Strokes (1978)

S2E15 The Dog Story (a.k.a.) A Dog Story

After Arnold heroically rescues a dog, he suffers a bite from the very animal he saved. In a twist of fate, the dog becomes essential for Arnold's survival. Meanwhile, the Drummond family goes on a frantic quest to locate the ungrateful pup while Arnold endures a grueling regimen of rabies vaccinations to avoid a dire fate.