The boy, who was not immediately named, was stabilized at Fairbanks Memorial Hospital and transported to Anchorage for further treatment.
Troopers say they were called to Reliance Drive about 6:25 p.m. Tuesday to a report of a pit bull attack. They found the boy with multiple puncture wounds in his torso and legs, troopers said. The dog was still in the area.
"While troopers were responding to the scene, the pit bull became extremely aggressive and attacked the patrol car," troopers said in a statement. "The dog was killed at the scene."
The attack comes less than a week after a 3-year-old girl, Krystal Brink of Kasigluk, was killed after she wandered into a Napaskiak yard and was attacked by a chained sled dog. In response, Brink's great uncle shot and killed six of the seven dogs in the yard.
A state Department of Health and Social Services spokesman on Wednesday said that the dog's remains tested negative for rabies.