[填空题]

Health officials in western Siberia are to begin in slaughter of thousands of birds today after identifying Russia’s first outbreak of a bird flu strain that can be fatal in humans. Doctors in neighboring Kazakhstan have also{{U}} (1) {{/U}}that a 19-year-old poultry worker{{U}} (2) {{/U}}admitted to hospital with{{U}} (3) {{/U}}of bird flu, only to be diagnosed{{U}} (4) {{/U}}double pneumonia.
The H5N1 strain of avian{{U}} (5) {{/U}}has killed 60 people{{U}} (6) {{/U}}2fib in Vietnam, Thailand, Cambodia and Indonesia, but has rarely been found in birds or humans{{U}} (7) {{/U}}Asia.
Health officials{{U}} (8) {{/U}}that HSN1 is infecting migrating birds, which could spread the{{U}} (9) {{/U}}into Europe. Earlier this year China registered the first outbreak of H5N1{{U}} (10) {{/U}}wild birds, some of which{{U}} (11) {{/U}}to breeding grounds in Siberia. These birds could come{{U}} (12) {{/U}}contact with others