document: Language : English Article Type : CSO -LSB- Article by Nigel Hawkes , Science Editor : `` Zoo Antelope Catch Mad Cow Disease '' -RSB- -LSB- Text -RSB- Scientists at London zoo have discovered that a strain of `` mad cow disease '' affecting a type of antelope can be transmitted much more easily than was thought . The finding uncovers a threat to breeding other species in captivity unless it can be shown that they are not equally vulnerable . The scientists say there is no evidence that similar transmission is occurring among cows . The zoo 's small herd of kudu , spiral-horned antelopes closely related to cows , has been severely hit by a disease similar to bovine spongiform encephalopathy -LRB- BSE -RRB- . Of eight animals born in the herd since 1987 , five have contracted the disease . Only one of the five could have eaten feed containing protein from sheep , believed to be the origin of the outbreak . The kudu is not the only zoo species to suffer the disease since it appeared in cows . It has also been found in domestic cats and their larger relations , the cheetah and the puma , in eland and nyala , and in the gemsbok and the Arabian oryx . In the United States , mink have been affected by it . The infective agent and its mode of transmission are unknown , but the evidence from kudu suggests that some species may be more easily infected than others . Sheep are believed to catch the disease by contact with placentas in fields after births , but in the case of the kudu even this route seems unlikely . In THE VETERINARY RECORD , the scientists eliminate most routes of infection . Infected feed can not account for four cases . Nor can at least three of the affected animals have caught the disease from their mothers , who did not suffer from it . It is possible but unlikely that the mothers were carriers that passed on the infection without having symptoms themselves . If this were so , it would have important implications for the disease in cows . It is more likely , the scientists believe , that an unidentified agent entered the herd in contaminated feed and was passed along , as with more mundane infections . Because of the danger to other animals , the kudu herd has been isolated . Another danger taken seriously by the zoo , a world centre for breeding rare and endangered species , is that animals bred in captivity could carry the infection when released into the wild . If they proved as vulnerable as the kudu , this could be disastrous . The scientists say that the next step must be to examine whether the agent causing the disease in kudu is the same as that in cows . If it is , the conclusion would be that the kudu were simply more susceptible to the disease . If , however , it turned out to be a different and more easily transmittable form , the case for isolating the kudu would be even stronger . TIMES NEWSPAPERS LIMITED , 1993
extractive_keyphrases: mad cow disease london zoo kudu herd affected animals similar transmission endangered species