A new scientific report characterizes the overall U.S. risk for the occurrence of bovine spongiform encephalopathy (BSE), commonly called mad cow disease, as extremely low. The Council for Agricultural Science and Technology (CAST) summarizes the latest information and disease statistics in its new report on transmissible spongiform encephalopathies (TSEs), a unique group of fatal diseases that can affect the nervous systems of animals and humans worldwide.

No cases of BSE have been found in the United States even though the disease has caused a major cattle epidemic in Great Britain and has been identified in nine other European countries. In March 1996, the British government announced a potential link between BSE and a new human illness, a variant of Creutzfeldt-Jakob disease (nvCJD). No cases of this unique human neurologic disease have been detected in the United States.

BSE can be prevented and controlled in spite of an incomplete understanding of the disease and the lack of live-animal diagnostic tests, said report cochair William D. Hueston of the Virginia Maryland Regional College of Veterinary Medicine. The cardinal point in BSE control is the willingness of veterinarians and renderers and members of the cattle industry and animal feed companies to implement and carry out measures such as disease surveillance and feed bans.

In May 1990, the United States began an aggressive BSE surveillance program to ensure timely detection and swift response in the event that BSE was introduced in the United States. Several government agencies are involved in the surveillance program and more than 250 federal and state regulatory veterinarians are trained to diagnose foreign animal diseases, including BSE.

The next few years should bring further knowledge on BSE and allow assessment of the effectiveness of public health measures established to prevent human exposure to BSE, said report co-chair James L. Voss of the College of Veterinary Medicine and Biomedical Sciences at Colorado State University.

Other TSE diseases do occur in the United States, including classical Creutzfeldt-Jakob disease in humans, scrapie in sheep and goats, chronic wasting disease in deer and elk, and transmissible mink encephalopathy. U.S. government animal and public health

Agencies continue major education efforts as well as specific control programs for these diseases. To fight scrapie, the U.S. government and industry have a surveillance program that traces exposed animals back to the farm of origin. The U.S. Department of Agriculture also has proposed new rules to support scrapie control by restricting interstate movement of sheep and goats and with pilot projects to evaluate flock cleanup plans based on testing.

A surveillance program also is in place for chronic wasting disease, which is found in free-ranging deer and elk populations only in 10 counties of north central Colorado and southeastern Wyoming.

Transmissible mink encephalopathy is a rare disease, with only five U.S. outbreaks recorded, the last being in 1985. Research and surveillance programs continue for this disease also.

CAST is an international consortium of 38 scientific and professional societies representing more than 180,000 member scientists. More information on CAST and its numerous scientific reports are available at www.cast-science.org Copies of reports, including Transmissible Spongiform Encephalopathies in the United States, are available from CAST at (515) 292 2125 or by e mail at cast@cast science.org.