What is Bovine Spongiform Encephalopathy?
Bovine spongiform encephalopathy, or BSE is an incurable and apparently infectious disease that attacks the brain and nervous system of cattle. Symptoms may include stumbling, muscle twitching, quivering, strange behavior, a drop in milk production, the inability to stand, and eventually death.
What causes BSE?
Evidence indicates that BSE likely occurred because U.K. cattle consumed animal feed derived from sheep and other ruminants (animals with four stomach compartments) infected with a neurological disease similar to BSE, called scrapie. Scrapie causes BSE-like symptoms in infected sheep.
How does BSE spread?
BSE does not spread from animal to animal or from animal to humans. BSE only spreads to animals through the ingestion of contaminated feed. Scrapie may have "jumped" the species barrier to cattle after the cattle consumed the animal feed rendered with sheep protein.
What has the U.S. done to prevent the spread of BSE?
The U.S. began a surveillance program for BSE in 1990 and was the first country without evidence of the disease to test for it. The surveillance system targets all cattle with any signs of a neurological disorder as well as those over 30 months of age and animals that are non-ambulatory. The U.S. utilizes a "triple firewall" strategy. First, the U.S. protects its borders. Since 1989, the U.S. Department of Agriculture (USDA) banned the import of cattle from countries with BSE. Second, the U.S. conducts vigilant surveillance at processing plants. USDA veterinarians are stationed at every U.S. meatpacking plant and check cattle for signs of any disease, including BSE. No animal can be processed for meat without a veterinary inspection. If cattle show any symptoms that could possible indicate BSE, they are removed from the plant and tested. Third, in 1997, the U.S. Food & Drug Administration instituted a mandatory ban on feeding ruminant-derived meat and bone meal supplements to cattle because of their ability to transmit the agent that causes BSE.
Does eating beef from BSE-infected animals make people sick?
Whole muscle cuts such as steaks and roasts are considered totally safe. However, there is evidence that neurological tissue such as brains and spinal cord from an infected animal may cause variant Creutzfeldt Jakob Disease (vCJD), a neurological disorder similar to classic CJD. None of these tissues (brain and spinal cord) are used in foods for human consumption in the United States. There has been no evidence that BSE is found in skeletal muscle tissues that are consumed by humans. While some 140 cases of vCJD have been diagnosed in the U.K. since 1986, these figures show how rare the disease is, and lend support to the theory that contracting vCJD may require a combination of exposure to BSE and a genetic predisposition to vCJD.
Is milk from an infected cow safe to drink?
BSE does not affect the lactation system, therefore milk and milk products are considered safe.