A virus may kill persons.Logical formLearned from13 sentences. Some persons may be infected with virus.Logical formLearned from13 sentences. A (dna virus) can be stranded.Logical formLearned from13 sentences. A (bird flu virus) can be in a continent.Logical formLearned from13 sentences. A virus may be found in a country.Logical formLearned from13 sentences. Research can be on a virus.Logical formLearned from13 sentences. Viruses may undergo an infection.Logical formLearned from13 sentences. Viruses can be in poultry.Logical formLearned from13 sentences. Viruses can be artificial.Logical formLearned from13 sentences. A (disease virus) can be infectious.Logical formLearned from13 sentences. A virus can be a factor.Logical formLearned from13 sentences. A virus may survive on surfaces.Logical formLearned from13 sentences. Hosts can be for a virus.Logical formLearned from13 sentences. A virus may propagate.Logical formLearned from13 sentences. Subtypes can be constituted-of-or-filled-with viruses.Logical formLearned from13 sentences.