Mad-Cow Disease Prompts Pet-Food Fears

News of the first confirmed U.S. case of bovine spongiform encephalopathy (BSE) is prompting pet owners to question the safety of pet food, which can contain infected body parts (brain, spinal cord, and distal ileum). Cats in Europe have contracted feline spongiform encephalopathy (FSE), the feline version of BSE from BSE-infected pet food. And several countries – including Canada – have implemented bans on U.S. pet food imports containing bovine meat and bovine-derived ingredients since the news was announced Dec. 23.

Many pet food manufacturers have issued statements about the safety of their food and some have specified the use of fish and chicken, not beef, as the primary source of protein. Veterinary experts say there is no cause for concern.

No companion animals in the U.S. have been diagnosed with BSE, one of several naturally occurring transmissible spongiform encephalopathies (TSEs) though approximately 100 cats in Europe were diagnosed with FSE. The majority of the cats were diagnosed with FSE in the UK in the early 1990s. After a ban on bovine offal in pet food passed in 1988, cases in cats disappeared, said Alfonso Torres, DVM, MS, PhD, and dean for veterinary public policy, Cornell University College of Veterinary Medicine.

To get the disease, animals and humans must consume large amounts of BSE-contaminated food over several days and exposure does not always ensure transmission, said Torres. “Also, there is information that some cases of FSE may have resulted from feeding cats raw butcher meats, not commercially prepared diets,” he said.

Other companion animals – including dogs, horses, birds and reptiles – are not susceptible to BSE, according to the U.S. Food and Drug Administration (FDA) and veterinary experts. “There is a great deal of variation in species susceptibility to TSEs,” Torres explained. “Dogs, pigs, all birds apparently are resistant to these diseases, and their species-barrier may be higher than for other animal species…. The same is true for many infectious diseases. Our pets do not acquire most human infections and vice versa.”

Citing rigorous national surveillance of cattle in the U.S. and redundant firewalls to prevent a BSE epidemic, some veterinarians say there is no cause for concern about pet food or human food in this country.

“Unless BSE is prevalent in the U.S. there is no reason to be concerned about pet food sources,” said Paul Morley, DVM, PhD, the director of infection control and biosecurity for the Colorado State University Veterinary Teaching Hospital. “It’s a little like smoking around your car. It’s not a problem unless you have a gas leak. And I’m personally confident that this occurrence is a rarity.”

Torres agreed. “Given the systems that the U.S. has put in place since 1989 to prevent the introduction and spread of BSE, and our restrictions upon production of animals and processing of meat for human and pet food, the risk of BSE-contaminated pet food is very small indeed.

BSE news spread rapidly when a Holstein cow born in Canada and raised in Washington State tested positive for BSE on Dec. 23.

Over the last few years the FDA implemented several safety measures to prevent BSE from becoming an epidemic and in 1997 it banned the use of brain, spinal cord and distal ileum from human food and cattle feed in the “animal feed rule.” The rule did not include pet food. Consumer articles have mistakenly reported that the FDA would extend the rule to include pet food in 2007, though there is no plan to do so, according to an FDA Center for Veterinary Medicine (CVM) spokesperson, who added that the BSE-infected cow “did not pose a risk to cats in the U.S. because none of it [the meat] was released into distribution.”

In 2003, when a BSE-positive cow was identified in Canada, the FDA stopped imports of pet foods made from mammalian sources, and a manufacturer recalled pet food that included infected meat. And in 2001 the U.S. banned the import of animal food, including pet food, containing ruminant materials from countries with BSE, according to the CVM.

While the Dec. 23 discovery may be, as some experts expect, the one and only U.S. case of BSE, the commotion opens a door for veterinarians to expand their role with clients.

“It’s an opportunity to reinforce the lines of communication with clients and be seen as more than just dog and cat doctors,” said Morley. “We are trained in areas of zoonotic disease and public health and this is an opportunity to exercise those muscles.”

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