 The concept is most commonly studied in virology, but cross-species transmission may also occur with bacterial pathogens or other types of microorganisms.
<clarity>  The concept is most commonly studied in virology, but cross-species transmission may also occur with bacterial pathogens or other types of microorganisms.
 The phenomenon is most commonly studied in virology, but cross-species transmission may also occur with bacterial pathogens or other types of microorganisms.