At least 94 Europeans have died from a human variant of the disease, called new variant Creutzfeldt Jakob disease, probably contracted from eating infected meat products. The disease is carried in nervous system tissue, not muscle, and is most likely to be found in products like sausage.
Mad cow disease was first identified in Britian in 1985, and a widespread outbreak infected more than 100,000 cows across Europe in the mid-1990s. The recent resurgence of the disease comes despite widespread beef import restrictions and other measures intended to protect the food supply.
Scientists believe the disease has spread among cattle primarily through so-called "animal recycling" -- the use of bone meal and other ground animal parts in commercial feeds. Several hundred cows in Europe have tested positive for the disease in recent months and thousands of animals have been destroyed. Carcasses are piling up at incinerators across Europe, and slaughterhouses are working overtime to destroy potentially infected animals.
The malformed protein that causes the disease (called a prion) is not easily killed by cooking or freezing and can survive for an indefinite period outside the body. Early symptoms in humans include insomnia, memory loss, and depression.
The European Union implemented new rules Jan. 1, requiring all cattle over 30 months old to be tested for the disease. The EU has set aside about $1 billion for the tests, which cost about $100 per animal. Europe also passed a ban on using bone meal in feed. The European Commission estimates the cost of incinerating slaughtered animals at $3.3 billion. European farmers and ranchers, devastated by plunging sales, are demanding compensation for destroyed livestock.
Meanwhile the U.N. and the World Health Organization issued a global alert Jan. 26, urging all nations to take steps to prevent the spread of the disease and to protect the food supply. That warning came one day after the first American cattle were quarantined in Texas, over concerns that they may have eaten unsafe feed.