Epidemiologists fear BSE’s final cost may be far higher. They say its incubation period seems to take decades in humans, and it is nearly impossible to detect until its terminal stages. Reputable scientists, extrapolating from data on roughly similar outbreaks of illness, have suggested that the death count from BSE’s incurable human form, Creutzfeldt-Jakob disease (CJD), could eventually top 125,000 in Britain alone. Meanwhile, health professionals around the world are debating the risks of infected blood donations and querying the past safety of every kind of cattle-derived product, from baby food and skin creams to polio vaccines and other medicines.
New warnings and worries emerge almost daily. London’s press reported last week that blood from a British donor, an undetected CJD victim, had been used to make a vital clotting agent used by hemophiliacs–and that blood products from the same source were shipped to 10 countries around the world, from Brazil to Dubai. British health authorities insist that the risk is utterly conjecture: there is no evidence that the disease can be transmitted in blood. Nevertheless, at blood banks in Australia, the United States and several other countries, donors are automatically rejected if they spent six months or more in Britain during the ’80s or early ’90s.
The U.S. Food and Drug Administration, similarly nervous, has been urging pharmaceutical manufacturers for the past decade to make sure their vaccines contained no cattle byproducts from anywhere BSE has been detected. Last week The New York Times reported that some international drug firms had disregarded the FDA’s requests. Still, the Centers for Disease Control and Prevention insist the danger from the vaccines is minimal.
The big risk is still from eating infected beef. The contagion raced across Britain in the 1980s, when farmers routinely fed their cows on the ground-up remains of cattle carcasses as a cheap protein supplement. Scientists now know that the BSE pathogen is highly infectious. Medical investigators estimate that a single gram of infected meat-and-bone meal (MBM) –a scrap no larger than a peppercorn–is enough to transmit the disease to a healthy cow.
Back in the mid-’80s, though, the disease was a mystery. While the epidemic raged among cattle, British grain dealers exported thousands of tons of potentially infected feed, mostly to Europe. As the Continent’s worries grew (France banned MBM imports in 1990), the British exporters shifted to other markets, notably Thailand and Indonesia. The exports didn’t end until 1996, when the government acknowledged that eating contaminated beef was a likely cause of CJD.
Britain has some hard questions to answer. Why did the government let the exports continue, despite warnings from the chief medical officer, Sir Donald Acheson? The government’s defenders argue that MBM feed poses no known threat to chickens, pigs, rabbits or anything else except ruminants and people. “It was up to other countries how they chose to use the material,” says a spokesman for Britain’s Agriculture Ministry. Besides, the defenders say, Britain shared its worries and its research into the causes of mad-cow disease. The importing nations could have toughened their laws accordingly–or so the sellers contend.
No one has yet measured BSE’s damage outside the EU. Britain’s export statisticians never knew how much of the MBM feed went to poultry and pigs, which seem to be immune to the BSE infection. At the same time, experts believe that plenty of Britain’s exports to mainland Europe were bought by middlemen for resale to third countries, making the trail almost impossible to trace. Andrew Speedy of the FAO says: “We are talking about a whole web of trade.” According to the FAO, the risks of infection are lowest in Australia, New Zealand and Latin America, thanks primarily to their largely self-sufficient farm systems. “Canada and the U.S.A. are unlikely to have BSE in their herds,” the FAO says, “but [the possibility] cannot be excluded.” The FAO’s assessment has not kept Canada from banning Brazilian beef, supposedly because of BSE fears, in a trade dispute between the two countries.
So far, only three human deaths have been attributed to the disease outside the United Kingdom: two in France and one in Ireland. The only known cases of BSE from tainted feed outside Europe seem to have been a handful of British-born cows in Canada, Oman and the Falklands. But the low tally could be misleading, World Health Organization officials say. Researchers there think many cases of BSE may have been overlooked by local health authorities or farmers who never thought to look for it as a cause of death in their herds. Remember, the disease was assumed to be almost nonexistent across most of Europe–until last year, when the European Union ordered a rigorous BSE testing program. Since then, more and more cases have been detected. This year alone, 23 have been found in France, 20 in Germany and 15 in Spain.
International health officials warn that a full-scale BSE outbreak in the developing world could inflict havoc. The disease has been tough on Britain, which has spent some $6 billion on efforts to eradicate BSE, including the wholesale slaughter of more than 4 million cattle. But such a blow could devastate the economies of many Third World countries. “I hope the disease will be completely restricted to the wealthy countries of Europe,” says Maura Ricketts, a mad-cow specialist at WHO. “But we just don’t know.” That’s the scariest part of the BSE epidemic: not knowing.
