Warning about a pandemic of mad cow disease in humans

British scientists said yesterday that people could be infected with human mad cow disease for more than 50 years without getting sick.

That means the scale of a pandemic of mad cow disease in potential people is underestimated. So far about 160 people worldwide have been infected with vCJD, a disease that causes brain aggravation to eat mad beef.

Lethal cases have been reported in many countries. British scientists believe that the incubation period of vCJD may be longer because the infection between cows and humans usually lasts longer in the same species. Prior to this study, scientists thought that the incubation period for vCJD was only 20 years.

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