ah... you just have to admire how old wives tales never really die...

Tetanus was known to ancient people, who recognized the relationship between wounds and fatal muscle spasms. In 1884, Arthur Nicolaier isolated the strychnine-like toxin of tetanus from free-living, anaerobic soil bacteria.

Now for the newsflash... if you really, really are fearful of contracting tetanus there is a miracle cure ( preventative actually) known as tetanus vaccine. So, if you are strolling down the road and accidentally step on a rusty old nail the first thing the doctor will do is give you a shot of tetanus anti-toxin and then follow it up with the regular vaccination ( which is good for ten years and then you go for the booster shot). In fact, it is deep puncture type wounds that create the anaerobic environment that the bacteria needs to thrive and, unfortunately for us, produce the by product that creates such horrible symptoms in mammals.