Mycotoxins are likely to blame for UK cat disease outbreak – Reuters

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Practitioners from the Royal Veterinary College investigated the cause of a 2021 outbreak of feline pancytopenia in the UK

Researchers have focused on toxins produced by fungi as a likely culprit in a severe 2021 outbreak of pancytopenia that killed at least 365 cats in the UK and sickened hundreds more.

Researchers have identified potato flakes in three brands of recalled pet food as a possible source of mycotoxins.

Naturally produced by fungi, mycotoxins can contaminate a variety of food ingredients. Exposure to high concentrations can cause many adverse health effects in animals, including humans, such as acute poisoning and immune deficiency.

One of the problems associated with exposure to mycotoxins is pancytopenia, a rare condition of the bone marrow that causes a rapid decrease in the patient’s blood cell count. The outbreak of pancytopenia in British cats has made international headlines due to the number of documented cases – at least 580, with a fatality rate of around 63%.

Early investigations appeared to rule out a range of suspects, including common feline infectious diseases, common toxic substances such as heavy metals and estrogen, and abnormal vitamin or mineral levels.

The first suspicions of mycotoxin involvement have been confirmed by two new research studies conducted by practitioners from the Royal Veterinary College of England and published on January 7 in the Journal of Internal Veterinary Medicine.

In one study, researchers analyzed data collected via an online registration forum available to all vets in the UK. The data included, among other criteria, patient demographics, clinicopathologic findings, and dietary history.

A total of 580 cats with pancytopenia observed in 378 practices were included for analysis. Dietary histories were available for 544 cats, 500 of which were fed one of three dry cat foods marketed by Fold Hill Foods that were recalled during the outbreak.

In five of the seven diet samples recalled, researchers found that the total concentration of two types of trichothecene mycotoxins, T-2 and HT-2, exceeded the values ​​recommended by the European Commission. One of the three control samples was also found to contain the same mycotoxins, but at a level within the EC guideline values.

A third type of trichothecene mycotoxin, diacetoxyscirpenol, was found in all seven samples of the recalled diets, and none in the control samples.

The scientists concluded that it is “reasonable to propose” that mycotoxin contamination caused the outbreak. They also called for standardized testing of cat food for mycotoxin contamination in the pet food industry.

The second study was a more in-depth analysis of clinical signs in 50 patients based on retrospective case studies and its authors drew a similar inference about the role of mycotoxins. They found various factors that “make a causal relationship likely,” including similarities in clinical presentation, similar clinicopathologic findings – particularly bone marrow findings – and the exclusion of other previously documented causes.

Interestingly, according to the researchers, all three brands involved were marketed as grain-free diets. Trichothecene mycotoxins are commonly associated with grain products, but have also been found in starchy root vegetables.

“The diets associated with the outbreak of pancytopenia in cats in the UK all contained potato flakes which, in this scenario, would have been the likely source of mycotoxin,” the researchers wrote.

The outbreak and related food recall prompted companies like supermarket chain Sainsbury’s and owner of pet store and veterinary practice Pets at Home to pull the diets from their shelves.

Pets at Home has since launched a £100,000 (US$122,000) grant to support researchers “who seek to better understand the disease, identify causes and improve treatment options”. Grant applications closed at the end of May 2022 and at least one study is ongoing.

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