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Ten years of BSE: Mad cow disease seems defeated

Ten years of BSE: Mad cow disease seems defeated

Ten years of BSE: Mad cow disease seems to be defeated.

Exactly ten years ago, on November 24, 2000, BSE was first detected in a German cow. Today, mad cow disease is almost defeated. With only two cases last year, BSE is also a thing of the past for the working group of German cattle breeders, as managing director Norbert Wirtz said in Bonn.

BSE first appeared in Deutschlad ten years ago
After the first appearance of bovine spongiform encephalopathy (BSE) in Germany in 2000 on the farm of Peter Lorenzen in Hörsten in Schleswig-Holstein, a real hysteria broke out. Since the causative agent can pass from cattle to humans and is believed to trigger a new variant of the fatal Creutzfeldt-Jakob disease (now known as nvCJD), both the health authorities and consumers were alarmed accordingly. Experts feared an epidemic with tens of thousands of victims, Federal Minister of Health Andrea Fischer and Federal Minister of Agriculture Karl-Heinz Funke (both SPD) had to resign and numerous products from "T-bone steak" to calf brain and salami to gummy bears (containing gelatin from cattle) suddenly came to an end as a health risk. The then Institute for Consumer Health Protection warned against “eating beef and sausage containing beef”, the beef market collapsed and numerous farmers were threatened in their existence. In addition to the development of a rapid test for the diagnosis of the dangerous epidemic, the determination of the causes of BSE was at the center of public interest.

BSE puzzle solved
Today, science has long since solved the key riddles surrounding the appearance of BSE. Accordingly, the disease was first identified in 1984 in a cattle in England. The animal showed inexplicable symptoms such as disorientation, frightfulness and aggressiveness, and when examined after death, veterinarians found that the bovine brain was holey like a sponge. They discovered the abnormally folded prion proteins that are characteristic of BSE and trigger a fatal biochemical process in a kind of chain reaction, which causes certain endogenous proteins to also adopt an abnormal fold and clump together. In the course of the disease, deep holes appear in the tissue and the affected brain takes on a spongy, perforated structure with thread-like, protein-containing deposits. The process affects brain function more and more as the disease progresses.

After the diseases were clearly diagnosed for the first time, the question of the causes and spread of BSE remained. The scientists quickly tracked down the so-called animal meal, which is left over from the processing of meat and the recovery of dead and sick animals. At that time, animal meal was widely used for fattening cattle, although critics criticized the unnatural diet of the actually vegetarian cattle even before the appearance of BSE. According to the experts, the defective prions have been transferred from the sheep to the cattle via the animal meal. Because unlike viruses and bacteria, prions can only be killed at a temperature of more than 133 degrees and a pressure of three bars. However, during the processing of the animal meal, this was often not heated sufficiently, so that the prions could spread to the cattle. Since 2001, this risk of transmission - and not because cows that eat sheep are unnatural - has banned animal feed from the EU. Since then, the number of new infections has dropped dramatically. "It is clear that feeding animal meal and animal fat has triggered the disease," said Martin Groschup, head of the Institute for New and Novel Animal Diseases at the Friedrich Loeffler Institute on the island of Riems near Greifswald.

Britain was most affected by the BSE epidemic
The epidemic was hit hardest at the time in Great Britain, where, according to official figures, around 180,000 cattle contracted BSE. "BSE has by no means shaken German cattle breeding as much as British one, where half of the cattle population has been culled," emphasized the head of the association of the German Cattle Breeders' Association Norbert Wirtz. Nevertheless, many cattle farmers would have given up. About every third person who was found to have BSE on his farm is no longer in business today. Because "according to EU guidelines, all animals that had eaten the same infectious feed had to be killed," explained Martin Groschup. As a result, the owners concerned lost their entire cattle population at a stroke, with 251 infected cattle found in various farms in Germany by the end of 2002, with corresponding consequences for the breeders.

According to the Federal Ministry of Agriculture, from January 1, 2001 to September 30, 2010, more than 20 million cattle in Germany were tested for BSE and 406 BSE cases were documented. At that time, all 166 cattle were also killed on the farm of Peter Lorenzen, but Lorenzen did not give up and started again with compensation from the animal epidemic fund. However, farmers now live from dairy cattle farming. In any case, the German beef market collapsed sharply in the wake of the crisis and considerable market share was lost to the poultry industry. According to the Federal Ministry of Agriculture, per capita consumption in Germany in 2000 was 14 kilograms of beef, dropped to just 9.9 kilos in 2001 and is now around 12.5 kilos.

The massive spread of the disease to humans has failed to materialize
The feared epidemic of spreading the disease through to humans did not occur contrary to the original fears. However, 200 deaths were caused by a new variant of Creutzfeldt-Jakob disease (vCJD), particularly in Great Britain (174 cases) and France (25 cases). According to Michael Beekes, head of the research group at the Robert Koch Institute in Berlin, it is “considered certain” that the pathogen that causes BSE and Creutzfeldt-Jakob disease is the same. According to Beekes, the estimated incubation period before the new Creutzfeldt-Jakob variant occurs in humans is between 10 and 15 years. Therefore, "it is not excluded that further cases of illness occur in humans", but with the introduction of a rapid test before the processing of the beef, the transmission risk was minimized. In addition, the spread of BSE in Europe has decreased to such an extent that the abolition of the tests is already being discussed in specialist circles. Even today, animals in Germany and a number of other EU member states are only being tested at least 48 months old. According to the European Commission, the epidemic in Europe is almost over and has gone much more gently than many experts suspected. But for the food industry, BSE remains one of the biggest scandals that Germany and Europe have experienced so far. (fp)

Photo credit: Alexander Litke / pixelio.de

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Video: BBC Documentary on Food Safety and Mad Cow Disease (March 2021).