Usually viruses move around within a single species, but scientists say pigs are different because their lungs have receptors that make them susceptible to swine, human and avian influenza viruses.

• 通常病毒都是在一个单一的物种传染，但科学家说，猪是不同的，因为他们的肺部有接受体，使它们容易受到猪、人和家禽的流感病毒传染。