SANDPOINT - Panhandle Animal Shelter officials say they are close to pinpointing the source of a canine distemper outbreak last month.

The compass needle is drifting toward puppies that were flown from a shelter in southern California earlier this year, according to Panhandle Animal Shelter executive director Mandy Evans.

"But at this point we are not 100 percent certain that that's where it came from," said Evans.

Evans said confirmation of the source of the outbreak has been delayed by the virus's six-week incubation period. However, the incubation period is about to lapse.

All told, 21 puppies at the shelter were diagnosed with distemper. Two of the puppies have died and necropsies on them confirmed the distemper diagnosis.

Shelter officials initially stated they didn't expect the illness to affect recently adopted dogs, but it turns out six puppies were adopted out before the outbreak was detected.

Three of those six puppies have been returned to the shelter and are being held in a quarantine ward, Evans said. The other three pups are quarantined at private residences.