A study that appeared in the on-line Lancet supports that a significant species barrier exists to prevent the transfer of bovine spongiform encephalopathy (BSE) or mad cow disease to humans.
The authors estimate that a person would have to eat at least 3.3 pounds of infected neural tissue to be at risk of developing variant Creutzfeldt-Jakob Disease (vCJD) — something that is unlikely to happen in the U.S. because tissues that could contain the BSE agent if an animal is infected are required to be removed from the human food supply. The authors also said that infectivity transfer from cattle to humans could be 7 to 20 times lower than cattle to cattle transmission through ingestion of the BSE agent. The study was done by French scientist Jean-Phillipe Deslys and his colleagues.
AMI Foundation President James H. Hodges explains that early in the BSE epidemic in the United Kingdom, before scientists fully understood BSE or its transmission, Britons routinely and unknowingly consumed infected parts from cattle like brains. "Yet less than 150 human cases of vCJD have occurred in the UK and the trend toward fewer vCJD cases each year has continued for the past four years," he says. "That's in comparison to more than 180,000 cases of BSE being diagnosed since the late 1980s and an estimated 3-4 million cases that could have occurred without clinical diagnosis, but were destroyed without testing."
Hodges adds, "Although the study has limitations that prevent accurately estimating the minimum infective dose for humans, its findings indicate that the BSE firewalls in place in the United States will continue to protect the public health. In simplest terms, Americans can continue to enjoy beef with confidence."