A North Vancouver owner is fighting an attempt to have her English mastiff, Walter, declared an aggressive dog after the mastiff allegedly attacked a puppy in training to be an assistance dog.

Auri Petrina launched a petition in B.C. Supreme Court last month, asking the court to overturn a designation from the District of North Vancouver that would require her to get Walter neutered and keep him muzzled and leashed in public, among other conditions.

Petrina said her dog is not aggressive. "I train my dogs every single day," she said. "Everyone's just trashing me and my dog."

Until very recently, Walter was among a handful of dogs who visited North Vancouver elementary schools with Petrina, helping kids to read as part of a program that provided an unflappable canine listener.

Petrina said as part of that process, Walter was assessed on two different occasions for U.S.-based organizations that register dogs to visit schools and seniors homes for therapeutic purposes.

The municipality, however, has not bought into the kindler, gentler version of Walter. It's animal welfare officer decided Walter was potentially an aggressive offender who needed tighter controls after Walter allegedly lunged after and injured a 12-week old Labrador retriever puppy near Sowden Park July 1.

According to documents filed in court by the district, Walter was being walked off his leash in the park when he suddenly ran outside the park boundary and set upon Miss Paddy, a puppy owned by the Pacific Assistance Dogs Society.

The puppy was rushed to Delbrook Mall Animal Hospital, where it was treated for shock and two large puncture wounds on its left shoulder and neck area. "One wound was quite large with a lot of crushing damage" and two layers of stitches were required to close it, according to court documents.

Kevin Pidwerbeski, director of the Pacific Assistance Dogs Society, said he remains very concerned about Walter.

"This animal has demonstrated it was an aggressive dog," he said.

Pidwerbeski said it costs between $50,000 and $90,000 to train an assistance dog, which are specially bred for the job, and the society only produces about 15 dogs a year.

Since the attack, Miss Paddy has been placed with a very gentle large dog as a form of therapy meant to help her get over her trauma, he said. But it's still possible the attack will mean Miss Paddy can never become an assistance dog as planned.

"I'm very angry about it," he said.

In a report to Pidwerbeski, Miss Paddy's handler said several of Petrina's neighbours came forward following the attack, saying Walter had attacked another puppy off-leash before. Neighbours said the owners reported that incident to the police, said Pidwerbeski.

The district animal welfare officer also said in his report, "This is not the first incident where Walter has displayed aggressive behaviour."

Petrina, however, said that isn't true. "It's not been proven," she said. "I've never seen my dog attacking any other dogs."

Petrina said she doesn't agree with the district's version of the dog-biting incident, although she declined to say what she thinks happened at the park until the case gets heard in court.

In designating Walter an aggressive dog, the district has asked Petrina to construct a pen to confine Walter on the property any time he is out of the house, to put up signs warning about the presence of an aggressive dog, take out a special licence and get $1 million in liability insurance.

According to the district, any dog that attacks either a person or another domestic animal unprovoked can be deemed aggressive under local bylaws.

But Petrina plans to argue that only a judge -- not the district's animal welfare officer -- can deem an animal aggressive and subject to special controls.

Petrina said she had to take the case to court because nobody would listen to her side of the story. "I'm not doing anything wrong. I'm not putting anyone in danger," she said.

In the past, several North Shore dog owners have fought municipalities in the courts after animal welfare officers sought to have their pets deemed "dangerous dogs" -- a more serious designation than "aggressive."

jseyd@nsnews.com