In America, chimpanzees are being used to develop a vaccine for hepatitis C because they are the only creatures, other than humans, to be afflicted by the disease.

• 在美国，研究人员借助黑猩猩研制抵御丙型肝炎的疫苗，这是因为，除了人类以外，只有黑猩猩会感染该病毒。