Blood donors are now asked specific and very direct questions about risk factors that could indicate possible infection with a transmissibledisease.
献血者如今都会被问到一些具体而非常直接的问题，即关于有可能感染到某一可传播疾病的一些风险因素。
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WHO estimates, for example, that this highly transmissibledisease could infect around one third of the urban population, or up to 4.5 million people, in Lagos, Nigeria alone.
Animals seem to be the main source of new infectious disease in man: in general around 60% of human pathogens are transmissible from animals; among new diseases, the rate is about 75%.