A person may be exposed to a virus.Logical formLearned from25 sentences. A man may be infected with a virus.Logical formLearned from25 sentences. A genus can be constituted-of-or-filled-with viruses.Logical formLearned from25 sentences. A virus may undergo variations.Logical formLearned from25 sentences. A (hepatitis b virus infection) can be chronic.Logical formLearned from25 sentences. Viruses can be common.Logical formLearned from25 sentences. A man may contract a virus.Logical formLearned from25 sentences. A woman may die from a virus.Logical formLearned from25 sentences. Human (immunodeficiency virus) may undergo a discovery.Logical formLearned from25 sentences. A virus can be powerful.Logical formLearned from25 sentences. A virus may be found in poultry.Logical formLearned from25 sentences. A virus can be from a family.Logical formLearned from25 sentences. A virus can be small.Logical formLearned from25 sentences. A (syndrome virus) can be acute.Logical formLearned from25 sentences. A virus may cause some deaths.Logical formLearned from25 sentences.