the first period of tropical medicine,

热带医学的第一个时期
from 1890 to just after the First World War,

从1890年到第一次世界大战之后
was a time, one of the times,

有一段时间一个时代
of the greatest epidemiological disasters in the tropical world,

在热带世界形成了最严重的流行病灾害
with virgin soil epidemics, like smallpox and measles,

属于处女地的流行病如天花和麻疹
and the impact of what was called constructive imperialism.

这类影响被称为建设性的帝国主义
Railroads, roads, trade, the transportation revolution,

铁路及公路贸易和交通运输的革命
all enabled a pandemic of bubonic plague, from the 1890s to 1920,

鼠疫的爆发从1890年到1920年
and epidemic influenza, in 1918 and '19,

流行性感冒从1918年到1919年
to occur in the tropical world as well.

同样发生在热带世界
Colonial wars, the involvement of the colonies in the two world wars,

殖民战争殖民地在两次世界大战中参与
had major disease impacts.

并受到重大疾病的影响