Possible Clues:

• Bug makes six hurry, in need of hospital
• Infective agent
• Sport in Six Nations finally showing destructive influence
• Irish American crushed by very nasty bug
• Submicroscopic pathogen
• Cybersecurity concern
• Mono, e.g
• Cause of computer malfunctions?
• Looking back, Irish king in gamey sort of transport initially quarantined in hospital?
• Doodlebug's endless surge -- unwelcome invader