What death rate and timeframe constitute a plague requiring public fasting?

Fasts & MourningHolidaysFasts and Mourning

Synopsis

A plague is defined numerically: 3 deaths in 3 consecutive days for a city of 500, or 6 deaths in 3 days for a city of 1000. Deaths on a single day or spread over 4+ days do not constitute plague.

Early Acharonim
Lenient
Strict
Lesser cited
Major authority

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