Madcow Disease (BSE)

On May 20, 2003 the Canadian government notified U.S. officials that the brain of an eight-year-old cow in a remote area of Alberta had tested positive for bovine spongiform encephalopathy (BSE, also known as Mad Cow Disease). According to Canadian officials, meat from the cow did not enter the food supply. Although BSE has not been shown to be transmitted among cows in a herd, as a precaution the herd in Alberta is being destroyed.

In addition, a second BSE positive cow was born and raised in a herd in Texas and was approximately 12 years old, according to information obtained from the owner. It was sent to a pet food plant in Texas and was selected for sampling on arrival.

The animal was non-ambulatory and did not enter the human food or animal feed chain. The remains of the animal were incinerated.

USDA will be working closely with the Texas Animal Health Commission and the herd owner to begin tracing any animals of interest for testing.

This second animal was sampled for BSE on November 15, 2004, as part of USDA’s intensive surveillance effort. Initial test results from a BSE ELISA rapid test were inconclusive. The sample was then sent to USDA’s National Veterinary Services Laboratories (NVSL) for further testing. Two Immunohistochemistry (IHC) tests were conducted and both were negative for BSE.

At the recommendation of the Inspector General, the animal was retested with a second confirmatory test, the Western blot. The results announced on June 10, 2005 were reactive. Additional testing by the United Kingdom’s reference laboratory in Weybridge, England and NVSL confirmed on June 24, 2005 that the animal was BSE positive but that the level of infection was low.

How are U.S. officials responding?

The U.S. Department of Agriculture (USDA), the U.S. Food and Drug Administration (FDA), other U.S. agencies, and Canadian officials are working together to gather additional information about the history of this animal, as well as records concerning its feed.

After the original outbreak of BSE in the United Kingdom in 1986, the U.S. government established a comprehensive set of measures designed to protect Americans and U.S. cattle from BSE. These included a list of "BSE countries" from which cattle, meat, beef-derived products, and animal feeds could no longer be exported to the U.S. As in the past, when individual European countries and Japan discovered their first cases of BSE, the May 20 announcement means that Canada will be added to the list of BSE countries. As a result, cattle, beef, beef-based products, and animal feed will no longer be allowed to be exported from Canada to the U.S. Possible further actions will depend on the findings from the current investigation of this one confirmed case of BSE in Alberta.

What is the risk to Arizona consumers?

The positive case in Alberta appears to be an isolated incident, but Canadian and U.S. officials are playing it safe. Since 1989, the USDA, the FDA and dozens of state agencies, including the Arizona Department of Agriculture (ADA) have implemented an aggressive prevention and monitoring rogram to keep BSE out of the U.S. These efforts include the following:

To keep BSE contaminated products from entering the country, the USDA started restricting the importation of live ruminants and certain ruminant products from the United Kingdom in 1989. More recently, the USDA banned the importation of any rendered animal protein products, regardless of species, from all of Europe and any other country known to have BSE.

In 1990, the U.S. started active BSE surveillance efforts. Since then, dozens of veterinary diagnostic laboratories across the country and USDA's National Veterinary Services Laboratories examine thousands of cattle brains each year submitted from animals displaying signs of neurological disorders either at slaughter or on the farm, or from animals that have died on the farm.

Because evidence suggests BSE may have developed in Great Britain as a result of the use of animal eed containing contaminated meat and bone meal as a protein source, the FDA established regulations prohibiting the feeding of most mammalian proteins to cattle. To ensure this federal rule is being followed locally, state agriculture officials conduct inspections of feed manufacturers.

The ADA, and the USDA work cooperatively to monitor the state's livestock for BSE warning signs. When cattle show warning signs, their brains are sent to the USDA for testing. To date, no cattle in Arizona or the U.S. have tested positive for BSE.

The U.S. government has a monitoring program that trains veterinarians in the clinical signs and diagnosis of BSE. Federal Foreign Animal Disease diagnosticians have trained in Great Britain in BSE recognition. In addition, BSE fact sheets, risk assessments, and reviews have been sent to state and federal veterinarians, private practitioners, other industries, and producers to keep them pdated and educated on the latest BSE research.

What is BSE?

BSE is a degenerative disease affecting the nervous system in cattle. It was first diagnosed in Great Britain in 1986. BSE belongs to a family of diseases called transmissible spongiform encephalopathies (TSE). BSE has never been found in the United States, but it has been detected in cattle in Europe, Canada, and Japan.

Scientists don't know the exact cause of the disease and there are no known treatments or vaccines for it. The BSE causal agent is thought to be a prion (abnormal protein). No one is sure where the BSE pathogen originated, but there are some hypotheses as to how it began. The most common and widely accepted theory is that the disease originated in Great Britain in cattle that ate feed containing products made from the carcasses of animals having some form of TSE (possibly sheep having scrapie). BSE is not believed to be transmissible from one live animal to another.

Why are people concerned about this livestock disease?

Evidence suggests BSE may be linked to a fatal human brain illness called variant Creutzfeld-Jakob Disease (CJD). Scientists suspect eating BSE-contaminated beef products can lead to variant CJD.

This variant form is not the same as the classical form of CJD that occurs sporadically at the rate of about one case per million in the U.S. Classical CJD has been around for many years, and it is not believed to be connected to consumption of BSE-contaminated beef. The Arizona Department of Health monitors the state for cases of variant CJD in humans. To date, no cases of variant CJD have ever been reported in Arizona.

What are you doing in Arizona to Combat BSE?

An enhanced surveillance plan for BSE was initiated in June of 2004 by the United States Department of Agriculture. The goal of this plan was to test approximately 250,000 high risk cattle in the United States within a 12-18 month period. The targeted animals for testing includes adult cattle showing clinical signs involving the central nervous system and dead and non-ambulatory cattle where clinical signs cannot be adequately evaluated. The plan also calls for the testing of 20,000 normal animals over 30 months of age at slaughter. All of the 176,468 samples tested in 2004 were negative for BSE. The 5604 negative submissions from Arizona accounted for 3.17% of the national surveillance. For recent information concerning BSE go to www.aphis.usda.gov/lpa/issues/bse/bse.html

In addition, laboratory scientists recently received training on the analysis of feed products to determine the presence of prohibited materials. The laboratory is cooperating with ESD regulatory officials to establish a plan for sampling feeds in the Arizona marketplace. In addition, the Department has contracted with USDA to provide laboratory space for the preparation of samples to be tested for the presence of BSE.