Canada confirmed on Sunday the existence of mad cow disease, or bovine spongiform encephalopathy (BSE), in a British Columbia dairy cow.

It is the country's fifth case of mad cow disease since 2003.

The national BSE surveillance program identified the cow on a farm in British Columbia's Fraser Valley, but initial screening tests proved inconclusive.

Samples were sent to the National Center for Foreign Animal Disease in Winnipeg for further testing last week.

However, the Canadian Food Inspection Agency (CFIA) said Canadian beef is still safe.

"Tissues in which BSE is known to concentrate in infected animals are removed from all cattle slaughtered in Canada for domestic and international human consumption," the CFIA said in a statement Sunday afternoon local time.

"No part of this animal entered the human food or animal feed systems."

The animal was a six year-old dairy cow. It developed mad cow disease after Canada's feed ban was implemented, but the CFIA claimed "similar situations are common to almost all BSE-affected countries that have introduced feed controls."

The CFIA will now investigate potential sources of infection, especially any feed given to the animal early in its life, collecting "records of feed purchased by and used on the animal's birth farm."

The surveillance program has tested more than 100,000 cows since 2003, when Canada's first case of BSE was found in Alberta.

Despite confirmation of a fifth case, the CFIA maintains that "the level of BSE in Canada is very low and declining."

Canada's cattle industry suffered badly after the 2003 BSE case was confirmed, costing producers more than 7 billion Canadian dollars (about US$6 billion).

BSE can cause a fatal disease in humans called variant Creutzfeldt-Jakob Disease, linked to eating contaminated beef. There is no treatment or cure for the disease, and it takes an average of a year to kill a patient.

(Xinhua News Agency April 17, 2006)