Complex sentence: Emergent viruses is a concept based on the fact that through certain selection pressures, viruses can adapt and can emerge as a new disease/pathogenic strain with a new attribute facilitating its pathogenicity in a new field not normally associated with that specific virus.
Split into simpler sentences: Emergent viruses is a concept based on the fact that through certain selection pressures. Viruses can adapt and can emerge as a new disease/pathogenic strain with a new attribute facilitating its pathogenicity in a new field not normally associated with that specific virus.