A virus may be contracted.Logical formLearned from41 sentences. A virus may sweep a continent.Logical formLearned from41 sentences. Presence may pertain-to a (bird flu virus).Logical formLearned from41 sentences. Viruses can be attenuated.Logical formLearned from40 sentences. (Virus attacks) may undergo a siege.Logical formLearned from40 sentences. A virus may cause (bird flu).Logical formLearned from40 sentences. A male may catch a virus.Logical formLearned from40 sentences. (Virus attacks) can be dangerous.Logical formLearned from40 sentences. (Anti virus updates) can be automatic.Logical formLearned from40 sentences. Hackers may unleash a siege of (virus attacks).Logical formLearned from40 sentences. A virus may undergo a propagation.Logical formLearned from40 sentences. A virus may break_out.Logical formLearned from40 sentences. A virus can be stable.Logical formLearned from40 sentences. Colds may be caused by viruses.Logical formLearned from40 sentences. A spread may pertain-to a human (immunodeficiency virus).Logical formLearned from40 sentences.