>>>沪江汶川地震专题

【首要问题：人口迁移】

灾后传染病的传播风险主要与人口迁移的数量和特征有关，具体包括：邻近是否有饮用水及可用的厕所，迁移人群的营养状况，人群接受过如麻疹之类的传染病免疫接种的比例，以及是否有卫生保健服务等等。（8）疫病在遭受自然灾害的人群中爆发的风险要低于遭受战争冲突的人群，后者中2/3的死亡可能是由疫病引起。（9）营养不良会增加因疫病死亡的风险，而这一情形在战争冲突中更为普遍，对于长期战乱导致的人口迁移来说尤为如此。（10）

对水灾后（11）疫病爆发的记载，比地震、火山爆发、海啸（12）后状况的记录更完备。然而总的来说，那些不会导致人口迁移的自然灾害（无论哪种类型）之后，几乎没有疫病爆发。（8）在历史上，由于自然灾害导致的大规模人口迁移并不常见，这很可能是人类历史上大规模疫病爆发并不频繁的原因之一（8），这也解释了为什么不同类型灾害后的疫病爆发风险各有差异。

Displacement: Primary Concern
The risk for communicable disease transmission after disasters is associated primarily with the size and characteristics of the population displaced, specifically the proximity of safe water and functioning latrines, the nutritional status of the displaced population, the level of immunity to vaccine-preventable diseases such as measles, and the access to healthcare services (8). Outbreaks are less frequently reported in disaster-affected populations than in conflict-affected populations, where two thirds of deaths may be from communicable diseases (9). Malnutrition increases the risk for death from communicable diseases and is more common in conflict-affected populations, particularly if their displacement is related to long-term conflict (10).

Although outbreaks after flooding (11) have been better documented than those after earthquakes, volcanic eruptions, or tsunamis (12), natural disasters (regardless of type) that do not result in population displacement are rarely associated with outbreaks (8). Historically, the large-scale displacement of populations as a result of natural disasters is not common (8), which likely contributes to the low risk for outbreaks overall and to the variability in risk among disasters of different types.