I don't think this is a biting fetish or cannibalism.

我觉得这事也许无关咬癖或是食人
I think it's a virus,

而是关于一种病毒
and the biting is merely a means of transmission.

撕咬只是其中的一种传播方式
What kind of virus?

什么病毒
There are several possibilities. Creutzfeldt-jakob disease,

有几种可能性克雅氏病
tick-borne encephalitis, but the most likely culprit is rabies,

森林脑炎病毒但最有可能的还是狂犬病毒
and that wouldn't show up in an autopsy except in brain tissue.

而且解剖时只有在脑组织中才能看出来
So since Lewis was the only victim not bitten by a human,

既然刘易斯是唯一没被人咬过的死者
the unsub must have used an animal to infect him first.

那嫌犯肯定是先利用动物让他染上了病毒
And after that, he somehow facilitated human to human transmission.

从那之后他就设计使其在人和人之间传播
That would explain the random victimology.

所以受害者类型才无规律可循
It doesn't matter who he infects.

病毒传染给谁并不重要