Europeans were subject to special diseases as challenges,

欧洲人受到特殊疾病的挑战
that arose as a result of conditions peculiar to warm climates,

在特殊气候条件下
and to the resulting conditions of temperature,

也就是温热的气候
humidity and local ecology.

湿度和当地的生态环境
Under those conditions,

在那些条件下
the diseases that would afflict Europeans were not, however,

这些疾病没有困扰到欧洲人但是
different in nature from those familiar at home.

那些不出门的人就不一样了
The diseases of hot countries

炎热的国家中的那些疾病
were heightened in their virulence, perhaps,

在他们身上也许毒力会增强
and the constitutions of white people

白人的体质
were now subjected to new and unfamiliar stresses

遭到了陌生的压力
that made them peculiarly vulnerable in these climates to disease.

使他们在那样的环境下更易受疾病侵害