After last week’s discussion on Rabies, I decided it was important to discuss another readily-controlled, animal-killing pathogen – Clostridium. This genus, or group of bacteria has more species members than any other genus of bacteria. A book could be, and probably has been, written about all of the Clostridial diseases that exist. Clostridium bacteria produce neurotoxins or tissue toxins when seeded into wounds or ingested. They generally favor environments that are anaerobic (without oxygen). A few of the more notable diseases featured in this group include tetanus, botulism (limber-neck in poultry), gas gangrene, and overeating disease. Others less commonly known include blackleg, red water, Tyzzer’s and black disease. Many people (and foals, lambs, etc.) have been infected with, and killed by C. difficile diarrhea. Any diarrhea, abscess (foot or otherwise), or hot, painful deep tissue infection in a vertebrate could well have a Clostridial source.
Many species in this genus live in the environment all around us, like Clostridium tetani, the organism that causes tetanus (not just on rusty nails!). Some areas of the country (notably Kentucky and Texas), have high levels of botulism in the soil and are avoided. Only a few years ago, C. botulinum bacteria growing in a batch of haylage produced a neurotoxin that, on ingestion, killed over 100 horses in the Ocala area. Botulism is an important disease of foals in the Kentucky area, and vaccination is recommended for broodmares and foals in that area of the country. As it causes flaccid (limp) paralysis, intensive care is required to support almost every bodily function during the weeks of recovery – eating, drinking, and breathing.
Tetanus, like botulism, can kill just about anything. While botulism is usually ingested or inhaled, tetanus is usually associated with a wound, often a puncture wound that is allowed to heal over, creating the perfect warm, airless environment for it to multiple and produce toxins. Its neurotoxin has the exact opposite effect than botulism: the uncontrolled paralysis is “tonic-clonic,” meaning the muscles undergo spasmodic continuous contraction. Stiffness will first be noticed in the limb or area near the wound, and will become generalized in a matter of days. The powerful clamping of the chewing muscles, often resulting in the subsequent starvation, dehydration and death of an animal affected by tetanus, is what gives rise to the term “lockjaw.” The body takes a rigid, arched position as the back muscles contract, overwhelming the abdominal muscles and pulling the head back. There are no blood tests to diagnose tetanus, but often the characteristic symptoms readily point to this historic culprit.
Control of tetanus is easily achieved through annual vaccination. A tetanus toxoid vaccine, given annually, is usually used for small ruminants, but can be given off-label to other species such as al pacas and llamas. Most horses receive their tetanus toxoid vaccine in the “EWT” (Eastern Encephalitis, Western Encephalitis, and Tetanus) combination product twice a year. Ruminants (cattle, sheep, and goats) are usually are given a “seven way” vaccine as youngsters, then annually and pre-breeding that includes overeating disease (C. perfringens). Generally vaccination is recommended starting at 4-6 months of age. The vaccines are inactive bacterial products, so unlike some vaccines, there is no risk of infection from vaccination. It is not uncommon for animals (and people) to be stiff for a day or two after vaccination.
If your animal receives a deep wound, call us immediately! Antitoxin must be given to animals that are not vaccinated if they receive a deep puncture wound that will predispose to infection. This antitoxin has been associated with reactions resulting in liver disease in horses, so regular vaccination is strongly recommended. Like for Rabies, vaccination is cheap, easy and effective! Don’t overlook this important and easily preventable disease when taking care of your horses and livestock.
In the meantime, my spoon splint is finally off!!! …although I still have an annoying bandage on my foot (which I continue to shake at people), I feel like my stall-turned-paddock (when I get to go out in the barn aisle-way) rest is close to over! May your food bowl always be full, and your litter box be ever-clean!
