[canuck_conservative]

through the mechanism of the flea!

The fleas needed a host - the rat. Why so many rats?

(a) lousy medieval hygienic practices like allowing garbage and sewage to run open in the streets (a similar thing happens today in South China, where viruses like SARS originate);

(b) persecution of cats? In medieval times these born-rat-killers were still seen as "agents of the devil"

??

[muawiyah]

With over 1,000 different CF gene mutations around, there must have been thousands of plagues ~ with most of them occurring during the last period of maximum glaciation!

Remember, everything on earth poops ~ so that's always around, as are rotten onions!