Rust Isn't What Gives You Tetanus
Before we go busting too many myths, let's get one thing straight: if you step on a rusty nail, you should absolutely make sure you're current on tetanus shots. However, that's not because rust causes tetanus—it doesn't. Tetanus is caused by a bacteria called Clostridium tetani, which makes its home in soil, dust, and feces. If you get a puncture wound from something that's been exposed to any one of those, regardless of whether there's rust, it's possible to become infected with tetanus. Nails are a common route for infection because C. tetani thrives in an oxygen-deprived setting like the one far below your skin's surface. Still, any injury that breaks the skin carries with it the potential for tetanus.
So why the old wives' tale about rust causing tetanus? According to HowStuffWorks, "...the thinking goes that if the nail has been outside long enough to get rusty, then it's probably been exposed to soils containing the bacteria." Rust also creates crevasses that give the bacteria a place to hide. If you suspect you're at risk for tetanus, it's a good idea to check if you're up to date on your vaccines. That's because C. tetani releases a powerful neurotoxin called tetanospasmin that can cause muscle stiffness and convulsive spasms that usually begin in the jaw—thus the infection's nickname, "lockjaw." Learn more about tetanus in the videos below.