MARTINEZ — A Concord couple has sued the owners of a kennel in unincorporated Walnut Creek after their mixed-breed dog was seriously injured during a weekend stay there, allegedly having been attacked by another dog.

The suit, filed Friday in Contra Costa Superior Court by Alan and Elizabeth Iannaconne, alleges that neither the owners of North Gate Kennels and Cattery nor kennel employees have ever contacted them since a Dec. 31 phone call telling them their dog Shadow had been injured, apparently in a fight with another dog being boarded at the kennel. The suit contends the kennel didn’t maintain a facility that could keep their dog separate from other dogs, and safe from attack.

A message left Friday afternoon at the kennel seeking comment was not immediately returned.

Shadow had to have surgery for 18 separate wounds, most notably ripped skin around his right ear and on one of his legs. The lawsuit also says that the Walnut Creek veterinary office that did the surgery wasn’t provided with any records or information about the other dog, including whether that dog was up-to-date on its shots.

LoriAnn Owens, the Iannaconnes’ attorney, said earlier this week that kennel owners had yet to give her clients any information about the incident, three weeks afterward, and had not allowed them to look at the specific kennels where Shadow and their other dog, Max, were brought ahead of a New Year’s weekend trip to Lake Tahoe, to meet up with family and friends. Shadow had been at that kennel a few times before that, Elizabeth Iannaconne had previously said, and nothing had gone wrong.

The suit alleges kennel employees had called them Dec. 31, saying Max had been injured the day before and taken to a Walnut Creek vet’s office for surgery (the kennel named the wrong dog, the lawsuit says; Max had not been injured). That call, the suit states, came more than 24 hours after Shadow had been injured, a violation of what the suit asserts is the kennel’s pledge to call an animal owner “immediately” if a problem arose.

The Iannaconnes rushed back from Tahoe to get Shadow, who for several days after his initial surgery lay curled up in a corner, growling at anyone, including family members trying to clean and dress the dog’s wounds, some of which later became infected.

The suit asks for unspecified damages.