Saturday, April 25, 2015

Tetanus: An Important Reminder for Gardeners by Sally Berriman

Cartoon by Microbiology2009
Last spring my girlfriend and I were constructing large tomato cages by bending metal fencing into a circle then securing it with wire and snipping off the excess fencing.  The fencing wasn’t cooperating and both of us sustained a number of scratches from the rusty metal.  Jokingly we started talking with our jaws clenched as if we had lockjaw.  After we had made a few cages and called it a day, I was washing my wounds and wondering when I last had a tetanus booster.  Not knowing how current I was, I “googled” tetanus to see if I was actually in imminent danger of having to eat everything through a straw.  This is what I discovered.

Tetanus is a serious infection.  It is caused by the bacteria Clostridium tetani which can be found almost everywhere in the natural environment.    If the bacteria gets into the body it can produce a toxin that can spread systematically throughout the body and interfere with the central nervous system, producing muscle stiffness, spasms, or rigidity and the infamous locked jaw.  Tetanus is potentially fatal.  Without treatment, one out of four infected people die.  Yikes!  Tetanus has a mortality rate of 25% in the U.S. and 50% worldwide. There are currently no blood tests that can be used to diagnose tetanus.  The diagnosis is based on the presence of tetanus symptoms. If you are infected, it can take a while for the symptoms to present themselves; anywhere from eight days to a few months.  It basically depends on how far from the central nervous system the toxin entered the body.

I was worried about the rust on the fencing but actually the rust itself does not cause tetanus.  It is the dirt on the fencing, not the rust, that carries the risk for infection. The bacterial spores lurk in soil, dust, and animal feces.  Tetanus occurs worldwide but is more common in areas with soil rich in organic matter, (like my vegetable and rose gardens, according to my recent CSU soil test).   This is particularly true with manure treated soil, as the spores are widely distributed in the intestines and feces of cattle, horses, chickens and sheep, (oh no, not my Sheep and Peat).   My dog and the neighborhood cats that wander through my gardens can also be carriers.
Dirt and Manure Carry Tetanus Bacteria Photo Alberta Health Services

And it’s not just stepping on a hidden nail in the garden that can infect us.  Any deep puncture wound can become infected; as can scratches, animal bites, torn flesh, burns or any wound that is contaminated with animal saliva or feces.  Now I’m thinking about all of the scratches from I’ve sustained while working with my roses, and what about my clippers, pruners, rakes and hoes? We gardeners work with sharp tools which can become contaminated by contact with dirt, manure or passing animals.   This means that we are frequently exposed to possible sources of infection, as many objects in and around gardens can harbor the bacteria. 

Doctors recommend that adults receive tetanus boosters every ten years.  Prevention via vaccination is nearly 100% effective and is far easier than curing it once you have been infected. Receiving a booster within 48 hours of an injury will increase your chances of a successful treatment if you do have an infection, but keeping current on your booster is a much better insurance against the disease.  Since I couldn’t remember when my last tetanus shot was, I headed over to my doctor and got one.  Now I’m protected and can work in my garden for the next ten years.  So my gardening friends, when was your last tetanus booster?