Pets at Home has sent a clarifying letter to vet practices after cases of cats becoming “seriously unwell” were linked to four products from the company’s AVA dry cat food range. It has also announced a “full independent review” of processes and testing protocols.

The products were withdrawn and customers told not to feed any they already had. A statement on the Pets at Home website confirmed that the level of thiamine (vitamin B1) was much lower than specified.

However, there were reports of confusion over the statement, which says the cats “affected exhibited symptoms of sudden collapse, fitting, widespread twitching and general unsteadiness which are not the classic symptoms of thiamine deficiency.”

A spokesman for the company said: “What we were trying to get across is that normally, one symptom of thiamine deficiency that vets recognise is cervical ventroflexion. That was missing in most of these cases.”

Cervical ventroflexion causes an inability to raise the head.

Peter Pritchard, Pets at Home chief executive office (retail) has  issued an open letter to vet practices. In this, he states:

“We were alerted after concerns were raised by a customer whose cat had become seriously unwell after it was switched to an AVA diet. During our investigations we were made aware of similar cases by vets at the Royal Veterinary College and Bristol Veterinary Hospital.

“Some of these cases showed cervical ventroflexion, but we believe it is important to alert vets that the predominant clinical signs in the reported cases are sudden onset ataxia, collapse, seizures, nystagmus or apparent blindness and leg splaying, which occurred four to six weeks after switching to one of the affected AVA diets without additional supplementation.

“Whilst these are well recognised signs of thiamine deficiency, there are many more common causes for these clinical signs and so vets may not put thiamine deficiency high on their list of differentials. Cases normally respond well to thiamine supplementation within 24 to 48 hours but there may be some residual neurological signs in severe cases.”

He adds that the products have sold in “relatively low volumes” since their July 2016 launch and that Pets at Home had begun an independent review of processes and testing protocols.