Dr. Katherine Briscoe

Photo courtesy of Dr. Katherine Briscoe

Veterinarians at The Animal Referral Hospital discovered a link between Weruva BFF cat food and neurological signs in cats. Dr. Katherine Briscoe, a feline medicine specialist, was one of the clinicians involved.

Cat food produced by an American company is linked with hundreds of cases of illness and as many as 20 deaths of pets in Australia. Weruva International Inc. of Natick, Massachusetts, recalled its Best Feline Friends (BFF) brand of canned cat food in Australia in early May but reports of illnesses are ongoing. Weruva states on its website that the problem affects only an Australian-exclusive line of BFF foods produced in a facility separate from other Weruva foods.

The suspected food was first identified by veterinarians at The Animal Referral Hospital in Homebush West. Dr. Katherine Briscoe, a feline medicine specialist there, answered questions from the VIN News Service by email.

Question: How did you come to discover the problem?

Answer: A potential association between the feeding of BFF cat food and development of clinical illness was initially discovered when three cases of neurological disease (predominantly cerebellar/central vestibular signs) were seen in close succession at the referral institution in which we work. In all cases, BFF was the predominant food fed, and the sole wet food.

The cases were reported through our industry body, the Australian Veterinary Association (AVA) via the PetFAST reporting scheme, which allows veterinarians to report potential pet-food related illness.

The cases sparked an emergency meeting between AVA representatives and the Pet Food Industry Association of Australia (PFIAA) to discuss the possible relationship between these cases. An electronic alert was sent to members of the AVA, and subsequent to the alert, veterinarians submitted reports on the PetFAST reporting scheme, which identified that non-neurological, clinical signs may be involved, [too]. (PetFAST is a joint initiative between the AVA and the PFIAA.)

Q: What are the associated clinical signs?

A: The reports we have received have detailed:

a) pyrexia, or fever, of unknown origin
b) gastrointestinal signs with temporal batch association
c) neurologic signs, particularly vestibular and cerebellar
d) odd effusions that despite extensive investigation fail to reveal FIP [feline infectious peritonitis] or other causes

Q: What do you mean by "temporal batch association"?

A: Temporal batch association means that there is a link between the particular batch of BFF being fed and the development of clinical signs. So rather than it being that all BFF foods are associated with clinical signs, there are some specific batches which result in clinical signs. [Weruva posted a table of affected batch codes.]
 
Q: What specific gastrointestinal signs are reported?

A: Vomiting, diarrhea and reduction in appetite, predominantly.

Q: How do the neurologic signs manifest? Are the cats having difficulty walking? Are they showing poor balance?

A: Clinical signs seen in cases of neurological disease have been predominantly wobbly when walking, abnormal head movements, falling over and reluctance to walk. [See video at right.]

Q: Will you elaborate on the odd effusions?

A: Effusions are the presence of fluid within the sac surrounding the heart, the chest cavity (around the lungs) or in the abdominal cavity. There are many causes of such effusions, but in the instance of the cases with possible association with BFF, there is no other cause identified, and in some cases the signs have resolved on changing the diet.
 
Q: About when did the first illnesses associated with BFF cat food appear?

A: The first case was identified in approximately April 2017.

Q: How many cases have been reported to date?

A: The exact number of cases is difficult to ascertain; however, approximately 300 cases are suspected. Almost certainly, not all of these cases will be associated with the feeding of BFF, and likely some will have unrelated illness.

Note that only about 40 or so cases [are reported] on PetFAST. An owner website [was] set up that took owners’ reports [and received the majority of case reports]. One of the website managers shared cases with the PetFAST team if owner permission [was] given. Cases also are reported on other social media sites.

Q: Any fatalities?

A: Approximately 20 of the cases reported have died or required euthanasia. However, these may not all have been associated with the feeding of BFF.

Q: Since the recall, have further cases appeared?

A: The sole distributor of BFF in Australia was, fortunately, quick to act in recalling all of these foods immediately after the index neurological cases were identified. However, the reporting of cases has continued.

Q: What do you think accounts for the continued reports? Might some BFF food remain in circulation? Is it possible the food isn't the culprit after all?

A: Whilst we can't be certain what the cause is, the recently reported cases that I am aware of have had the food in their pantry, [have] been unaware of the recall, and have continued feeding the food. Or alternatively, the clinical signs have been present for some time but no connection was made to the feeding of BFF by the veterinarian involved. 

Q: Are any other foods or sources implicated?

A: In the cases for which full diet history is available, no other foods or sources have been implicated.

Q: Is a government agency tracking reports and investigating the cause?

A: As there is no legislation regarding pet food in Australia, no government body is tracking or investigating. Australia does not have an equivalent of the U.S. Food and Drug Administration. All the work done on the investigation and the analysis has been done pro bono by the initial investigators and the AVA’s PetFAST volunteer veterinarians.

Following the development of renal tubulopathies in a large number of dogs fed particular jerky treats, our industry body, the AVA, established the PetFAST reporting scheme, which allows veterinarians to report any suspected pet-food-related illness. If required, further investigation is performed. Thus, the AVA are currently tracking reports.

With respect to investigation as to the cause of the illnesses, five of five tins tested at our National Measurement Institute showed extremely low or negligible thiamine concentrations, so we have recommended thiamine supplementation in any of these cats, regardless of underlying complaint. Not all varieties of this canned food are labeled as complete and balanced for adult cat maintenance, but [they] are labeled “complete," and instructions are provided for feeding as a sole food. The company website indicates the food complies with [standards set by] the Association of American Feed Control Officials, or AAFCO.

Q: Do I understand correctly that the labeling indicates that the food provides a complete diet, albeit the labeling does not claim the diet is "balanced”? What is the AAFCO standard for thiamine content in complete and balanced diets? By how much has testing shown the BFF diets vary from the standard?

A: As far as I am aware, the labeling on different BFF types varies. According to the AAFCO website, a "complete" diet has all the nutrients required for that species, but a "balanced" diet contains those nutrients in the correct ratios.

With respect to the recommended amount of thiamine in a pet food, the recommendation for most nutrients varies between age groups, and the information is obtained via AAFCO publications. We have results only for the canned foods tested by us, and not the wider results of canned foods tested by the company, but in the most severe circumstances, thiamine was not detected in the canned foods at a level that could be measured (i.e. it was almost non-existent). As an essential nutrient in cats, this is substantially below the recommended feeding amount.

Q: How many cases have you personally treated? Please describe the nature of illnesses, nature of exposures and the patients' health status today.

A: I have treated or been associated with treatment of three patients. All three cats had neurological signs, with one also having a fever of unknown origin. In all patients, BFF was the predominant diet and the sole wet food. All three cats are currently healthy, though in one cat, fever of unknown origin is persistent.

Q: In these cases, did the signs resolve once BFF was withdrawn? if yes, how long did it take for the patients to recover?

A: Clinical signs began to improve within a few days of commencing a different (and balanced) diet. The time for complete resolution varied depending on the severity of the initial clinical signs. In some cases, resolution of clinical signs on removal of BFF from the diet, and recurrence of clinical signs when BFF was reinstituted, was documented. 

Q: About how long has BFF been sold in Australia?

A: I am not sure, but my understanding is that it has been available for approximately one to two years.

Q: As imported food, is BFF subject to irradiation?

A: No.

Q: What are your thoughts about possible causes?

A: The actual cause of the signs is still not known and could well be multifactorial. Given [that] thiamine levels are low in the foods tested, and thiamine deficiency can cause the neurological signs seen in these patients, it is possible that thiamine deficiency is one of those factors.  

Blood mercury levels in these cats are all higher than sick or well controls but not anywhere near the blood levels associated with conventional toxicity. (As mercury targets the cerebellum in cats, it was the initial focus of investigation.) Mercury levels in some of the tins would likely exceed European Union tolerance limits if our calculations and assumptions regarding the moisture content of the food are correct (i.e., not toxic but definitely contaminated, so mercury may play some sort of role given its selective uptake in various neurologic tissues in humans under different conditions, e.g., stress, exercise, etc). Blood and urine arsenic levels are also high, so we are intending to send urine away for arsenic speciation.

The neurologic signs tend to resolve reasonably quickly when off the food, and it is hard to know whether the neurologic signs are self-resolving or thiamine-responsive (with thiamine provided in new food or supplement).

The gastrointestinal signs in affected cats do not appear to resolve so quickly. Some effusive cases have responded to prednisolone in addition to thiamine.

Q: Has Weruva been sharing information with veterinary researchers or other organizations in Australia? We tried to reach them but have received no reply.

A: Unfortunately, no, the Weruva Company have not been sharing information with us, and aside from initial discussions, have not been working collaboratively with us at all.

Editor's note: This story has been changed from the original to correct statements about the diet of the affected cats seen in Dr. Briscoe's practice. The cats were fed BFF wet food predominantly but not solely.