One of my blog readers shared last week that her daughter’s dog was recently diagnosed with tetanus and is undergoing treatment. Poor doggie! I am fervently hoping that her dog responds and will have a complete recovery! She asked if I could write about tetanus and shed some light on this infection in pets. In truth, I think we are much more aware of tetanus in ourselves than in our pets. We all know that we are supposed to get a tetanus shot at least once every 10 years, and if we get poked in the foot by a rusty nail, we need to get a booster shot. What’s the deal with this infection?
Tetanus is caused by a bacterium called Clostridium tetani. This organism is a dirty bugger. Really, it lives in the dirt. So when we step on a rusty nail, or cut our hand on an old tin can, there’s a good chance that C. tetani is there, contaminating our wounds. It happily grows in that wound, and it isn’t the infection itself that causes the problem. Rather, it’s the fact that C. tetani produces a toxin called tetanospasmin that acts on the nervous system, causing muscle spasms, contraction, and rigidity. The term “lock-jaw” refers to rigid muscles in the neck and cheek areas that prevent a person or animal from fully opening the mouth.
This toxin is really powerful. The minimum human lethal dose is around 175 nanograms in a 150-pound person. One nanogram is one-billionth of a gram. One gram is roughly the weight of a dime. So we’re talking about splitting a dime into a billion pieces, and 175 of those pieces is enough toxin to take down an adult person. Yikes. I personally am really glad we have a effective an vaccine to prevent this painful and potentially deadly disease.
It turns out that humans (and horses and livestock) are more sensitive to the effects of tetanospasmin than are cats, which are quite resistant. Dogs have intermediate sensitivity. Horse owners are used to vaccinating for tetanus, as it is considered a core vaccine for all horses. We don’t routinely vaccinate our pets for tetanus, though. This doesn’t mean they can’t get it, it’s just pretty uncommon.
When a dog develops tetanus, often it starts as the localized form. This means perhaps only the foot or one leg has muscle spasms and rigidity, and typically this occurs in the area of the wound and site of infection. The localized form can develop into the generalized form, and the dog’s ears will be pinned, brow furrowed, lips pulled back. Seizures can occur, and the dog may have trouble breathing.
Treatment includes antibiotics to kill the C. tetani in the wound, anti-toxin to neutralize tetanospasmin that hasn’t already bound to the nerves, and muscle relaxants and anti-seizure medications. These animals are very sensitive to light, loud noises, and other stimuli, so it’s important to keep them in a dark and quiet place while they are in treatment. A dog with tetanus may also need help eating and drinking. It may take a week and as long as a month for full recovery.
I want to thank Gail for sending me this topic idea. I hope you learned something, and if you have topic ideas, please share them!