Infection can be with viruses.Logical formLearned from17 sentences. Subtypes may pertain-to a virus.Logical formLearned from17 sentences. A virus may be pass_oned.Logical formLearned from17 sentences. (Blood transfusions) may be tainted with a virus.Logical formLearned from17 sentences. Vaccinations can be against a virus.Logical formLearned from17 sentences. A member may pertain-to a (virus family).Logical formLearned from17 sentences. A virus may flare.Logical formLearned from17 sentences. A virus can be in birds.Logical formLearned from17 sentences. A virus may be identified as a strain.Logical formLearned from17 sentences. Levels may pertain-to a virus.Logical formLearned from17 sentences. A (bird flu virus) may ravage (poultry stocks).Logical formLearned from17 sentences. A virus may lead to a disease.Logical formLearned from17 sentences. An explanation can be a virus.Logical formLearned from17 sentences. Viruses may invade human cells.Logical formLearned from17 sentences. A virus may infect animals.Logical formLearned from17 sentences.