MACDONALD G
Bull World Health Organ. 1956;15(3-5):369-87.
The natural disappearance of malaria from certain areas-a phenomenon which has for many years been observed in various parts of the world-is discussed in relation to the recent deliberate elimination of the disease from large tracts of land. The process of elimination, the detection of residual foci, and the ways in which the disease may be reintroduced into a country are outlined briefly, and the course of events in epidemics which arise from small origins is described in detail. The factors affecting the basic reproduction rate in such epidemics-mean duration of infectivity of a primary malaria case, density of mosquitos in relation to man, and longevity and degree of anthropophilism of the vector concerned-are analysed, and a simplified method of expressing this rate mathematically is given in an annex.
疟疾在某些地区自然消失——这一现象多年来在世界不同地区均有观察到——本文结合近期在大片土地上有计划地消除疟疾的情况进行了讨论。简要概述了消除疟疾的过程、残留疫源地的检测以及疾病可能重新传入一个国家的途径,并详细描述了由小范围起源引发的疟疾流行中的事件过程。分析了影响此类疟疾流行中基本繁殖率的因素——原发性疟疾病例的平均传染期、与人类相关的蚊子密度以及相关病媒的寿命和嗜人性,并在附录中给出了以数学方式表达该繁殖率的简化方法。