Category Nuances matching outbreak:

• viral,
• destructive,
• significant,
• negative,
• major,
• natural,

Members for simple category outbreak:

• cholera_epidemic,
• influenza_pandemic,
• attack,
• deliberate_outbreak,
• love-letter_epidemic,
• milwaukee_outbreak,
• white_spot,
• yellow_head,
• sars_epidemic,
• measles_epidemic,