The attack happened at 2:00 p.m. Thursday in the 300 block of Cedar Street.
Police say the officer was helping the SPCA respond to a loose dog complaint when the pit bull terrier lunged and bit the officer's foot, penetrating the officer's boot.
He was taken to Wilmington Hospital, treated for a puncture wound and released. The officer did receive a rabies shot, however the results of the quarantine will determine if he needs further treatment.
The dog is described as a tan and white female pit bull terrier weighing about 45 pounds. Its owner has not been identified.