A virus can be respiratory.Logical formLearned from594 sentences. A case may pertain-to a virus.Logical formLearned from592 sentences. A virus may kill some persons.Logical formLearned from588 sentences. Viruses can be known.Logical formLearned from587 sentences. Strains may pertain-to a virus.Logical formLearned from579 sentences. Exposure can be to a virus.Logical formLearned from528 sentences. A virus can be in a country.Logical formLearned from479 sentences. A person may have a virus.Logical formLearned from479 sentences. Protection can be against viruses.Logical formLearned from449 sentences. A strain may pertain-to a (bird flu virus).Logical formLearned from437 sentences. Cases may pertain-to a virus.Logical formLearned from434 sentences. A virus can be mysterious.Logical formLearned from420 sentences. A virus may pertain-to a male.Logical formLearned from419 sentences. A virus can be transmitted.Logical formLearned from399 sentences. Viruses can be deadly.Logical formLearned from393 sentences.