The U.S. Department of Agriculture (USDA) has announced the detection of an atypical case of Bovine Spongiform Encephalopathy (BSE), a neurologic disease affecting cattle. (Unofficially BSE is called Mad Cow Disease.) The case was identified in a beef cow at a slaughter plant in South Carolina, estimated to be around five years old or older. However, it is important to note that this animal never entered the slaughter channels, ensuring that there was no risk posed to the food supply or human health in the United States. Consequently, the USDA does not anticipate any trade impacts resulting from this finding, considering the country's negligible risk status for BSE.

The confirmation of the atypical L-type BSE in the affected cow was made by the USDA Animal and Plant Health Inspection Service's (APHIS) National Veterinary Services Laboratories (NVSL). The testing was conducted as part of APHIS's routine surveillance of cattle that are unsuitable for slaughter. The animal was traced back to a herd in Tennessee through its radio frequency identification tag. Both APHIS and veterinary officials in South Carolina and Tennessee are actively gathering more information as part of an ongoing investigation. Atypical BSE is generally observed in older cattle and is known to occur rarely and spontaneously in various cattle populations.

This recent case marks the seventh detection of BSE in the United States. Among the previous six cases, the first instance, which occurred in 2003, involved classical BSE in a cow imported from Canada, while the subsequent cases were all atypical (H- or L-type) BSE.

The World Organization for Animal Health (WOAH) recognizes the United States as having a negligible risk for BSE. According to WOAH guidelines, atypical BSE cases do not impact the official BSE risk status recognition, as this particular form of the disease is believed to occur spontaneously at a very low rate in all cattle populations. Therefore, the identification of this atypical case will not alter the negligible risk status of the United States and should not give rise to any trade concerns.

The United States maintains a robust system of interlocking safeguards against BSE, ensuring the protection of public and animal health. Key measures include the removal of specified risk materials, which are the parts of an animal that could potentially contain BSE if the animal were affected, from all animals presented for slaughter. Additionally, a stringent feed ban is in place to prevent cattle from exposure to the disease. The ongoing BSE surveillance program plays a crucial role in the early detection of the disease, even at very low levels within the U.S. cattle population, exemplifying another vital component of the safeguarding system.