The dead Hanford, CA dairy cow with laboratory-confirmed bovine spongiform encephalopathy (BSE) is now the centerpiece of an investigation into whether there are any more mad cows in the vicinity.
Dairymen in the Central Valley of California have been told state and federal officials are testing the BSE-infected animal’s feeding herd, which could include some of its own offspring, and other cows in the area that were born about the same time.
A spokesman for Western United Dairymen said its members maintain “meticulous records” on birth dates, parentage, and linkages to other animals – all easily traceable – and such documentation should help investigators.
Baker Commodities, the Los Angeles-based company that owns the transfer rendering station at Hanford, also announced it not only was holding the diseased carcass in cold storage, but all other cows that arrived with it on the same truck.
It was Baker’s participation in a random sampling program that returned the BSE-infected brain tissue, one of 40,000 samples USDA plans to take this year.
The BSE-infected carcass is in quarantine where it will remain until state and federal officials ordered it destroyed. The exact location of the dairy farm where the diseased cow lived and died on or before April 18 has not been disclosed.
The Hanford dairy cow did not show any “mad cow” signs – such as difficulty walking – before it died, making investigators especially interested in testing its calves and cohorts.
Officials conducting the investigation are not going to be surprised if they do not find anything. BSE is not a contagious disease, and is not spread through casual contact between animals.
USDA scientists believe transmission is usually through feed contaminated with a sufficient amount of tissues or organs containing the BSE agent from an infected animal .
That is why the practice of recycling bovine carcasses into a meat and bone meal protein product was banned as cattle feed.
The Hanford dairy cow was found with an atypical BSE not believed to have originated with feed.
While the investigation continues, 48 hours after the announcement the beef industry was breathing a big sigh of relief. On news that Canada, Europe, Japan, South Korea and Mexico do not plan to change their import policies, cattle prices sprang back from panic selling that occurred just before the announcement.
In some quarters, the beef industry was even crediting itself for “swift reaction to BSE case,” to lift part of a headline from the industry journal Meat & Poultry.com.
“Industry reaction to a recently confirmed case of bovine spongiform encephalopathy (BSE) came swiftly as trade groups, scientists and educations worked to quiet concerns about the safety of the U.S. beef and milk supply,” Meat & Poultry reported.
The beef industry was also happy to have both government officials and consumer advocates telling the public the discovery of the mad cow was no threat to the food supply, including meat and dairy products.
From a risk viewpoint, the odds of getting human mad cow disease were reported to be one in 10 billion even after eating something contaminated with a BSE agent. And the odds were figured not by a Nevada bookie, but by the Centers for Disease Control and Prevention.
While the Hanford cow is only the fourth BSE case discovered in the U.S., there is another kind of animal prion disease also relevant to humans, according to the National Prion Disease Pathology Surveillance Center in Cleveland.
That other kind is Chronic Wasting Disease (CWD), a prion disease of elk and deer. It is not at all uncommon for elk and deer hunters to find animals infected with CWD. Chronic wasting occurs at epidemic levels in the U.S. elk and deer herd of about 22 million, mostly centered in about a dozen western and Midwestern states.
Since November 2004, the surveillance center, located on the campus of Case Western Reserve University, has performed autopsies on 26 hunters with suspected prion disease, but says all had either sporadic or familial forms of the disease, meaning there has not yet been any documented case of transmission to a human from an elk or deer.
Also, no case of the human version — called variant Creutzfeldt-Jacob Disease or vCJD — has ever been associated with U.S. beef. In 2004, vCJD caused a death in the U.S., but originated in the United Kingdom. In 2006, there were two vCJD deaths in the U.S., but one originated in the UK, and the other in Saudi Arabia.
If the latest BSE case in California were feed-related, it would be a different story because trace back of the animal’s feed sources would be required, and some wonder whether USDA could pull that off.
Congresswoman Rosa DeLauro, D-CT, said the nation’s fourth case of mad cow disease underscores the need for a strong national animal identification system. USDA needs “to improve animal traceability and ensure the health of our domestic livestock,” she said.
Beyond the brands and tags they have always used, farmers and ranchers have for a decade resisted new animal ID schemes proposed by USDA.© Food Safety News