the case for contagion still seemed weak.

传染病的说法还不够权威
There wasn't a mechanism to explain what it was,

没有一个合适的机制能够解释它是什么
how it was transmitted.

或者它是如何传播的
In many cases, close inspection seemed to

大多数情况下密切监察显示
demonstrate that the disease spread without the direct

这个疾病不是像假设的那样
contact that the contagionist view seemed to postulate.

需要直接接触传播
People caught the plague who hadn't been in immediate contact

人们不需要直接与另一个瘟疫患者接触
with another plague victim.

就会感染瘟疫
Conversely, where there was such contact,

反过来说只要发生类似接触
often the plague didn't spread,

瘟疫往往就不会传染
and people who cared for a plague victim sometimes didn't fall ill.

有时照顾瘟疫患者的人却不会感染
How could that be explained?

这该如何解释呢