Pigs are flu sponges, capable of contracting both bird and human viruses that can jump across the species barrier, Richt says.
里希特说，猪是流感海绵，能够跨跃物种界线吸取人类和禽类的流感病毒。
2
Richt and his colleagues drew together a frightening array of studies of flu viruses extracted from people and a small zoo of animals over the past several decades.