Cats across the UK are dying in significant numbers from a 'mystery illness' that they believed could be linked to widely sold cat food brands.

Vets around the UK are believed to have been inundated with cases on pancytopenia, a condition in which the number of red and white blood cells, as well as platelets decrease rapidly, causing really severe illness.

The Royal Veterinary College (RVC) reported this week that it was aware of at least 528 cases in cats over the past few months, with 63.5% cases proving fatal, The Guardian reports.

The true number of deaths could be far higher, however, as many cases have not been reported.

The true number of deaths could be far higher
The true number of deaths could be far higher

Certain batches of Sainsbury’s hypoallergenic cat foods, Applaws and AVA (a Pets at Home brand) were recalled by their manufacturer in mid-June.

This prompted an investigation by the RVC and the Food Standards Agency (FSA).

The length of the investigation is reportedly causing frustration among cat food suppliers.

One cat owner, whose pet died on Tuesday, have warned that too few people are aware of the recall and could be feeding their cat potentially fatal food products.

Steven Barrett, a commercial barrister from High Wycombe, said his nine-year-old cat, Freyjal tragically died on Tuesday after five days of illness.

Certain batches of Sainsbury’s hypoallergenic cat foods, Applaws and AVA were recalled
Certain batches of Sainsbury’s hypoallergenic cat foods, Applaws and AVA were recalled

Barrett said Freya had finished the last of a 7.5kg bag of its Applaws dry chicken food when she began vomiting.

He said he had heard nothing about the product recall until he went to buy more food online and saw it wasn't available- which led him to research into why.

“My heart went through the floor,” he said.

“She was a member of our little family, which is how we treated her. I just wanted her to have the best food.”

Barrett phoned his usual vet but was unable to get an appointment as they were full with similar cases.

“When the receptionist heard the name of the cat food she just told me to get an emergency appointment at another vet. I took her yesterday and she was dead by the end of the day,” he said.

“My worry is that a lot of cat owners bulk buy dry food and this is a massive recall, so there could be toxin in bags of dried food that will be opened and given to cats and more cats will die.”

Although the RVC and FSA investigations are ongoing, a statement on the RVC website eludes to the possibility that the illness could be caused by mycotoxins, which are caused by types of fungi.

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Mycotoxins can grow on crops before or after harvest and appear on things like cereals, nuts, spices, dried fruits, apple juice and coffee - usually under warm and humid conditions.

All of the brands that have been recalled are dry foods manufactured by Fold Hill Foods, part of the Lincolnshire-based farming JW Grant.

A spokesperson for Fold Hill said: “As stated by the FSA, there is no definitive evidence to confirm a link at this stage between the cat food products and feline pancytopenia.