Actually, people die from oral/fecal contact all the time. Every time you see an e Coli outbreak on the news, there's a good chance the cause was a food handler who didn't wash after wiping. Hep A outbreaks at daycares and schools are usually caused by poor hygeine/oral-fecal transmission.
We're not talking huge scads of shit. We're talkiing the tiniest bit on an unwashed hand. Bacteria isn't like alchohol or drugs--it proliferates, grows, multiplies in favorable environments. So all it takes is a microscopic bit to kill. And believe me, e Coli kills.
Kallie