Chronology: the spread of mad cow disease

The following are key dates in the spread of mad cow disease, believed to be transmitted by contaminated meat-and-bone meal fed to cattle:

1986

November - Britain makes first diagnosis of bovine spongiform encephalopathy (BSE), a new disease in cattle.

1988

July - Britain announces that all cows known to be infected with BSE will be destroyed as a precautionary measure. Eventually 3.7 million cattle were destroyed.

1989 - Britain bans human consumption of certain offal, including brain, spinal cord, thymus, spleen and tonsils. The United States prohibits the import of live ruminants, including cattle, sheep, bison and goats, from countries where BSE is known to exist in native cattle.

1990

- European Commission bans imports to the Continent from Britain of cattle over six months old.

1993

December - One beef cow in Canada diagnosed with BSE. Authorities say it had been imported from Britain in 1987. The animal carcass and the herd it came from are destroyed.

1994

EU approves proposal to ban exports of meat, containing bones, from herds that had not been free of BSE for six years instead of two.

1996

British government admits for the first time that BSE could be transmitted to humans in a variant form of Creutzfeldt-Jakob disease (vCJD). The classical form is a slow degenerative disease in humans seen in about one person in a million worldwide each year.

March - Japan bans imports of meat-and-bone meal from Britain.

March 23 - Fast food chain McDonald's Corp. suspends the sale of British beef products in its restaurants in Britain.

March 27 - EU ban on British beef and beef products announced.

August 1 - Britain's agriculture ministry confirms that mad cow disease can be passed from cow to calf.

August 19 - British coroner rules that Peter Hall, a 20-year-old vegetarian who died of the vCJD, contracted it from eating beef burgers as a child. The verdict is the first to legally link a human death to mad cow disease.

1997

August 7 - The US Food and Drug Administration prohibits feeding of most mammalian proteins to ruminants.

December 3 - Britain bans the sale of unboned beef as a precautionary move to stop the risk of mad cow disease.

1999

August 1 - Export ban on British beef following the mad cow disease scandal is lifted after 3-1/2 years.

October 29 - The European Commission's top scientists give British beef a clean bill of health.

2000

June 29 - British Agriculture Minister Nick Brown announces that a cow, born after measures were introduced to eradicate mad cow disease, had been found to have BSE.

December 7 - The United States prohibits all imports of rendered animal protein products, regardless of species, from Europe.

2001

September 10 - Japan's Agriculture Ministry says a dairy cow tested positive for mad cow disease in the Chiba area near Tokyo, the first outbreak in Asia.

2002

April 19 - US health officials report the first suspected case of variant Creutzfeldt-Jakob disease (vCJD), the human form of mad cow disease, in a 22-year-old British woman living in Florida. They said she most likely contracted the disease while living in Britain.

August 8 - Health Canada says a Canadian man died in Saskatchewan from vCJD, apparently after contracting the disease in Britain.

2003

January 30 - World Health Organisation warns that contaminated feed was exported to many countries in central and eastern Europe and Southeast Asia and says they are at risk of BSE.

May 20 - Canada says one cow in Alberta tested positive for BSE, Canada's first case since 1993. Canada Agriculture Minister Lyle Vanclief said the animal "did not enter the food chain" and its origin was being investigated.

May 20 - United States temporarily bans imports of Canadian cattle, beef and other ruminants and ruminant products.

May 21 - Australia, Japan, South Korea, Taiwan, Mexico and other nations ban imports of Canadian beef.

May 22 - Canada broadens hunt for origin of Alberta mad cow case to Saskatchewan and expands quarantine to seven herds in the two provinces. US officials said they are mulling whether to isolate Canadian cattle now in US feedlots. Russia, Singapore, Chile and Indonesia ban imports of Canadian beef.

May 23 - Canada expands quarantine to a total of 13 cattle herds in Alberta, Saskatchewan and British Columbia in mad cow probe. US National Farmers Union demands more cattle tests at the US-Canada border before US ban on imports lifted.

May 25 - Canada says that 192 cattle in same herd as BSE-infected cow from Alberta test negative for the disease. Canadian beef industry says losing US$8 million ($12.6 million at today's exchange rate) a day from banned beef and cattle exports and other sales.

May 27 - Canada says Alberta's BSE-infected cow likely came from Saskatchewan and a second test of the infected cow's herd mates was negative for BSE. Canada opposition politicians assailed the Ottawa government for slow testing of cattle.

May 28 - China and Brazil ban Canadian beef imports. Canada says will test 600 more cattle in mad cow probe in attempt to track down source of the infected Alberta cow's disease. Canada cattle industry says losing US$20 million a day during probe.

July 18 - Canada introduces new safeguards against mad cow disease to force its crippled beef sector to remove risky organs from carcasses, a move its top trading partner, the United States, said was key to lifting its import ban.

November 4 - Japan says it has confirmed another case of mad cow disease, the ninth since the brain-wasting illness was discovered in the country in September 2001 and the second in less than a month.

December 23 - At least one confirmed case of the deadly mad cow disease found in an animal in Washington state, a US Agriculture Department official said.

- REUTERS