Page 106 - Jan_2020

“To avoid risk for this kind of infection,
by Heather Smith Thomas
Many horsemen give injections to their horses. These include vaccinations, anti- biotics, and sometimes other medications.
Most injections are given intramuscularly, but there are a few medications that should always be given intravenously.
Intramuscular injections occasionally cause local abscesses if the needle or skin is dirty when the injection is given. Sometimes, abscesses occur even with very clean conditions. The worst kind of injection-induced infection is called clostridial myositis, or myonecrosis.
This type of infection is caused by certain types of clostridial bacteria that are present in the environment. Some of these bacteria live in the horse’s intestines and don’t cause problems under normal conditions. They are present in manure and form spores that last a long time in the environment. They are often on the horse’s skin and can be taken into the tissues with an injection. These bacteria can be in a dormant state, and then multiply when conditions are right, growing best in an airless environment without oxygen, such as bruised
cause different diseases. Examples include: tetanus, malignant edema, blackleg in cattle, enterotoxemia in young calves and foals, or life-threatening gut infection and diarrhea in young foals.
Some types of intramuscular injections seem more risky for clostridial infections, especially flunixin meglumine (Banamine and its generic equivalents), if given in the muscle rather than in the vein. One theory is that this drug sets up an ideal pH in the tissues for these bacteria to grow (basic, as opposed to acidic).
A clostridial infection can happen with any kind of injection, but Banamine has been the most common.
Dr. Ray Randall, a semi-retired veterinarian in Bridger, Montana, says to be aware of the possibility of adverse reaction any time you give an injection. “This can occur with vaccinations, injections of vitamin E and selenium, etc. But Banamine is the one we are most aware of (since it seems to be most often associated with reactions), and it doesn’t matter how well you give the injection; there is always a risk. Clostridial bacteria may already be in the horse’s body in spore form, just waiting for something to set up the right environment (such as damaged tissue from the injection),” he says.
Irritation from the drug can cause part of that muscle to die. Normally this is not a big deal, but it can set up an anaerobic environment which enables clostridia to thrive. It’s not the bacteria themselves that cause the problem; it’s the toxin that they secrete. When they multiply, they produce toxins that damage the surrounding tissue even more and produce gas. You can feel air bubbles under the skin – crinkly like bubble wrap.
“I have some slides taken many years ago of a horse I treated in 1989 for a clostridial infection following vaccination. He survived, but was disfigured from the infection and was just used as a lesson horse after that,” says Randall.
“With Banamine or any of the generic flunixin products, the only way to minimize the risk is to give it orally or IV, and never in the muscle. It does have an intramuscular label on the bottle [stating that it can be given either IV or IM] though there is also a warning about possible adverse reactions when given IM, which include clostridial infection.” This drug is safest to give orally, but works fastest if given IV.
“When people are giving injections of any kind, the number one thing is to be clean. Don’t inject into a dirty area on the neck or buttocks. We used to use alcohol, but it really doesn’t do much good (it’s not a very good
products like Banamine should never be injected into the muscle.”
The dormant spores “come to life” when they have favorable conditions in which to multiply and start producing deadly toxins. Different clostridia
CLOSTRIDIAL MYOSITIS
Following Injections and Precautions for Banamine Injections
flunixin and damaged tissue with very little blood supply.
A horse will go off his feed and be depressed when affected by clostridial bacteria, which produces toxins that not only damage local tissues and affect the entire system but can also spread around the muscles.
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EQUINE HEALTH