A gourmet imported petfood has been withdrawn from sale after an outbreak of chronic illness and death among Sydney cats.
Vets have put down at least five cats over the past week and treated more than a dozen others suffering from paralysis.
Dr Georgina Child said the only factor that linked all the cats was a specialist pet food called Orijen, which is imported through a Canadian company, Champion Petfoods.
"There is a highly suspicious link because this is an uncommon expensive food in this country at the moment, and not sold in supermarkets," Dr Child said.
"But all tests that have been done so far haven't given us an answer."
First symptoms included wobbliness or weakness in the animal's hind legs, which could then progress to the front limbs.
The condition did not appear to be infectious, Dr Child said, nor typical of a nutritional deficiency.
The marketing manager of Champion Petfoods, Peter Muhlenfeld, confirmed the cat deaths had been traced back to Orijen's dry cat food, and the problem appeared to be restricted to Australia.
He said samples sent back by the Australian distributor had a "strange odour".
The company is investigating whether irradiation upon entry into Australia was the source of the contamination.