Transmission of the vaccine virus to non-immunized birds should be avoided. 須避免將疫苗病毒傳給未免疫的禽類(lèi)。
The discovery of swine flu in birds in Chile raises concerns about the spread of the virus, the UN warns. 聯(lián)合國警告道,智利發(fā)生家禽類(lèi)感染豬流感事件激起人們對病毒傳播的顧慮。