Presence may pertain-to a (bird flu strain).Logical formLearned from16 sentences. A version can be constituted-of-or-filled-with (bird flu).Logical formLearned from16 sentences. Forms can be constituted-of-or-filled-with (bird flu).Logical formLearned from16 sentences. Fears can be about a spread of (bird flu).Logical formLearned from16 sentences. A (bird flu outbreak) may begin.Logical formLearned from16 sentences. Treatment can be for a flu.Logical formLearned from16 sentences. A (flu season) may end.Logical formLearned from16 sentences. A (flu vaccine) may be developed.Logical formLearned from16 sentences. A (flu vaccine) can be painless.Logical formLearned from16 sentences. Persons may catch a flu.Logical formLearned from16 sentences. An attack can be constituted-of-or-filled-with flu.Logical formLearned from16 sentences. Flu can be in birds.Logical formLearned from16 sentences. A cause may pertain-to a flu.Logical formLearned from16 sentences. Cases may pertain-to a (bird flu strain).Logical formLearned from16 sentences. A resurgence can be constituted-of-or-filled-with (bird flu).Logical formLearned from16 sentences.