隔离防疫
Isolation and Epidemic Prevention
The earliest institutionalized epidemic isolation system — the Han Dynasty (c. 2 CE) established 'li qian suo' (疠迁所), dedicated quarantine facilities for leprosy and other infectious disease patients. One of humanity's first systematic public health interventions.
Scientific Principle
Isolation cuts the transmission chain. Modern epidemiology formalizes this: basic reproduction number R₀ → effective reproduction number R_e = R₀ × (1 - isolation proportion). When enough contacts are isolated, R_e < 1 and the outbreak declines. The Han quarantine system and Venice's 14th-century 'quaranta giorni' (forty-day isolation, origin of the word 'quarantine') are the two earliest institutionalized quarantine practices in recorded history. PMC9009840 notes that ancient Chinese quarantine was 'occasional and unsystematic' compared to modern mandatory isolation. COVID-19 (2020) re-validated quarantine as an indispensable tool when vaccines and drugs are unavailable.