Tetanus in dogs

Written by Dr Andrew Miller MRCVSDr Andrew Miller MRCVS is an expert veterinary working in the field for over 10 years after graduating from Bristol University. Andy fact checks and writes for Pure Pet Food while also working as a full time veterinarian. Pure Pet FoodPure Pet Food are the experts in healthy dog food and healthy dogs featured in media outlets such as BBC, Good Housekeeping and The Telegraph. Working with high profile veterinary professionals and nutritionists, Pure Pet Food are changing dog food for the better. - Our editorial process

Tetanus is something you might have heard of before, you might have had a vaccine against it at one time in your life. This knowledge could paw-ssibly be accompanied with random warnings about scraping your skin on a rusty old nail or an animal bite as to not catch the disease.

Many years ago, the prospect of developing tetanus was extremely frightening as it’s a paw-tentially life-threatening illness. Nowadays, advancements in medicine have supplied us with an effective vaccination programme meaning that tetanus is quite a rare disease today.

However, is this the same for our dogs?

We’re going to provide you with all the information you could possibly need about what tetanus is, how dogs can catch it, how to spot it and how it’ll be treated.

What is tetanus in dogs?

Tetanus, also commonly referred to as ‘lockjaw’, due to its ability to impede the typical function of the jaw, is an infection that can have fatal consequences for your dog.

A wound is the initial trigger of tetanus, allowing bacteria to enter and produce a deadly toxin that spreads throughout the body. It has a detrimental effect on the nerves, spinal cord and the brain.

Development of the toxin

Clostridium tetani, the bacteria that triggers the toxin, is pretty widespread, naturally being present in a lot of soil. Animals can also excrete the bacteria in their stools, further implanting the bacteria into the environment.

Clostridium tetani can live in the environment for years, meaning your pooch probably has encountered the bacteria at one point. However, it’s only really if they get a wound that the bacteria will infiltrate and cause any damage to your dog.

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A dog can develop tetanus when clostridium tetani seeps into a superficial wound. This puncture wound becomes a breeding ground for the bacteria, due to the low-oxygen environment, which luckily means that the bacteria can’t cause any issues in your dog’s gastrointestinal tract or on the skin as the oxygen levels aren’t right for the bacteria.

As the bacteria reproduces, the bacterial cells begin to die and dissolve in the site of the wound, resulting in the powerful poison tetanospasmin being emitted. This toxin has debilitating consequences, spreading to the nerves encircling the wound site and eventually impacting the spinal cord and brain.

As a result, the nerve signals become abnormal, predominantly causing your pup to experience muscle contractions, and extreme, exaggerated muscle reactions to stimuli.

So, it’s not actually clostridium tetani, the bacteria, that’s the issue here, as your dog can come into contact with it often on their skin, it’s the toxin that’s produced afterwards that causes tetanus.

How do dogs get tetanus?

We all know our dogs can get a little bit ruff when playing. They can go absolutely bonkers when they’re having fun, and it probably makes you cringe every time you think they’ve hurt themselves.

Every so often, they’ll likely hurt themselves. This could be from an accidental play bite from their pooch pal, standing on a sharp object or they might have just stumbled over and grazed their skin.

Whatever it is, you might start thinking, ‘could they get tetanus?’, ‘will they need a tetanus shot?’. Just to pause that thinking immediately, dogs are much more resistant to tetanus than humans are, so it’s unlikely they’ll develop the condition. But it can still happen when they get an injury.

As we know, tetanus is caused by the tetanospasmin toxin released after clostridium tetani invades the body through an open wound that’s been in contact with contaminated soil. We know dogs can get wounds in various ways, it’s just a part of everyday life for a pup.

The general idea believed by many is that this condition is contracted after stepping on or catching the skin on a piece of rusty metal. However, it’s not the rust of the metal causing tetanus, it’s just if that piece of metal has been exposed to the bacteria. Even the cleanest piece of metal could have clostridium tetani bacteria residing on it, ready to bury into your pooch’s skin.

What are the signs and symptoms of tetanus in dogs?

The symptoms can vary for tetanus, but the main one is your dog having stiff, rigid muscles.

Other signs to look out for are:

  • Muscle tremors

  • Muscle contractions

  • Muscle spasms (can make the forehead appear wrinkled)

  • Inability to bend legs, all 4 legs held rigidly in what’s called the ‘sawhorse stance’

  • Sunken eyes

  • Constipation

  • Erect ears (if your dog has floppy ears that hang down, you may notice them starting to stand erect)

  • Inability to blink

  • Visible third eyelid (needed to dampen eye)

  • Sensitivity to light

  • Tail held up or extended behind them

  • Sensitive to touch

  • A grinning, smiling appearance

  • Difficulty breathing, drinking and eating

  • Struggling to swallow (leads to drooling)

The time it takes for these symptoms to become apparent can vary, sometimes it can be as early as 3 days after point of infection, or it can even be up to 3 weeks. Typically, the symptoms will arise between 5-10 days after the initial wound was contracted.

Dogs have a much higher resistance to the toxin than we humans do, meaning they do have quite a long incubation period. The incubation period is the number of days it takes from the initial point of infection to the point of symptoms manifesting.

Due to the various problems tetanus can cause in the eyes, many often mistake it for some form of eye disease at first.

What are the types of tetanus in dogs?

There are two types of tetanus your dog can develop, localised tetanus and generalised tetanus.

Localised

This is the most common form of tetanus that our pets encounter. It is characterised by stiff muscles and sometimes muscle tremors that only affect the limb and muscles closest to the initial wound. Sometimes, localised tetanus can progress into generalised tetanus, but this isn’t always the case.

Generalised

Generalised tetanus is where symptoms arise throughout the dog’s entire body, or at least widespread areas, rather than just the location of the initial wound. This type of tetanus is definitely more severe in both appearance and the impact it has on your pup, meaning that the signs are easier to spot early on.

The ‘sawhorse stance’, where all legs are held rigidly, and their tail is extended behind them is one of easiest things to spot if your dog is suffering with this disease.

Due to the persistent muscle contractions caused by generalised tetanus, many dogs actually develop a fever. This isn’t actually caused by the disease, this is the secondary aftermath of the heat produced by the muscles constantly contracting.

Take a look at your dog’s mouth, as this is also a big indicator of generalised tetanus. In some cases, it may look like your dog is flashing you a grin, but this is actually a symptom referred to as risus sardonicus, which originates from Latin, meaning ‘sinister smile’. This smiling effect is caused due to the muscle spasms that tetanus creates in the lips.

On the other hand, your dog’s mouth could be held tightly shut, hence why this condition is often labelled as lockjaw. The jaw will be rigid and essentially locked, which can result in big puddles of drool being left all over your floor. Eating will become difficult, and it can even result in spasms happening within the throat and diaphragm, which is the muscle that oversees breathing.

Consequently, breathing will become a huge struggle for your poor pooch, potentially having fatal outcomes.

Are some breeds of dog more likely to get tetanus?

Tetanus isn’t really a common condition in dogs, but dogs that spend a lot of their time outdoors are at a higher risk of developing the disease as they will be more exposed to contaminated soil in their day to day lives.

How does tetanus differ in humans and dogs?

Surprisingly, us humans aren’t that dif-fur-ent from our canine counterparts in terms of what illnesses we get. Both humans and dogs can develop tetanus, and the symptoms that both person and pooch encounter aren’t too dissimilar.

Tetanus was once quite common within humans, but nowadays a tetanus jab is just a normal part of our vaccination set.

However, our dogs have a much higher immunity from the disease than we humans do. Luckily, this means that the likelihood of your pup developing tetanus is pretty rare, and dogs therefore don’t qualify for a tetanus vaccine.

Despite this, it’s good to have knowledge of the condition in the event that it does happen, so you know to look out for the signs if your dog does have a wound.

How is tetanus in dogs diagnosed?

Diagnosing tetanus is primarily based on the signs and symptoms of the disease that your dog is displaying and their history of having a wound.

This can become slightly hazier when the wound is not present anymore. Since the symptoms can begin around 10 days after the point of infection, the injury may have fully healed before any symptoms were ever noticed. Or, it may have been that small it was completely unnoticeable and the owner didn’t even spot it.

Localised tetanus can be even harder to diagnose too as the symptoms are much more toned down compared to generalised tetanus, especially if a wound is not found.

Without the presence of a wound, it leaves quite an im-paw-tent clue unavailable to the vet, however, the symptoms are that obvious your vet should spot the condition pretty quickly. If your vet suspects tetanus, they may conduct further tests such as blood and urine tests.

How is tetanus in dogs treated?

The treatment methods for tetanus vary, mainly depending on how advanced the disease has become. If tetanus is left untreated, it will progress and become extremely detrimental to your dog’s health, potentially becoming deadly.

Early in the course of the illness, your vet may administer a tetanus antitoxin to reduce the severity in which your pooch suffers from the symptoms of tetanus. Antitoxin operates by attaching itself to the tetanospasmin toxin that is starting to circulate throughout your dog’s body, stopping the toxin in its tracks so it can’t bind to the nerve cells.

This needs to be administered extremely early on, as once the toxin has managed to latch onto the nerves, the antitoxin will have no impact and no benefits. Your vet will determine if it’s deemed appropriate to give your dog the antitoxin as it can bring on some rather significant side effects, so it must only be given if the vet is sure it’ll work.

If the toxin has spread too far, antibiotics will be given to treat tetanus. They don’t have any impact on the actual toxin, but they’re used to eradicate the clostridium tetani bacteria. This prevents the bacteria from releasing any more of that deadly poison. A number of antibiotics can be used to eliminate clostridium tetani, your vet will select the best one for your pooch based on their symptoms.

In cases where a wound is found, your vet may decide to surgically debride the injury. This entails removing any dead tissue circling the wound, with the objective of destroying as much of the clostridium tetani bacteria as possible.

The more bacteria the vet can remove, the more chance there is of controlling the swift spread of tetanus, as this will prevent more of the toxin being released into the wound and surrounding areas.

Dogs suffering from tetanus will need around the clock care. If your pooch is experiencing the ‘lockjaw’ symptom, it’s likely that they will need intravenous fluids and feeding tubes as they’ll be finding it hard to eat and drink. Even your pet’s surroundings need to be controlled - quiet, dark rooms are the ideal environment to limit stimulation. Loud noises and bright lights can increase the likelihood of muscle spasms.

Also, the infected pup will need to sleep on clean, soft bedding and be turned over regularly, this should prevent any pressure which could lead to decubital ulcers (bed sores).

Will my dog recover from tetanus?

If provided with the optimum care, most pooches suffering with tetanus will eventually make a full recovery, however, this all depends on the severity of the disease.

Localised tetanus is the most common form of the disease and most dogs experiencing this type of tetanus will respond really well to suitable treatment if provided early. Usually, they’ll see a massive improvement within a week of treatment, but some can take a couple of weeks to fully recover.

If your dog is experiencing generalised tetanus and their muscles are really struggling and they’re unable to stand, the recovery rates become worse. Sometimes, full recovery can even take months. Overall, various studies report a 50-90% survival rate for dogs suffering from severe cases of tetanus.

Can tetanus in dogs be prevented?

There isn’t really a hard and fast way of preventing your pup from getting tetanus as preventatives aren’t really necessary against the condition in the canine world.

As stated, our dogs are tough cookies and have a really high tolerance against tetanus. Strangely enough, cats have an even higher level of resistance to the condition! Due to this level of resistance, a tetanus vaccine isn’t available for our pooches.

Multiple vaccines to prevent the onset of tetanus for humans, sheep and horses have been produced, but there isn’t one for dogs as it isn’t necessary.

The most effective way you can help as a pooch paw-rent is by appropriately cleaning, flushing and treating your dog’s wounds if you happen to notice any. This should hopefully aid in reducing and eradicating any clostridium tetani spores that may have infiltrated the injury.

If you notice any strange changes in your dog, such as stiffness and tremors, contact your vet quickly for an examination.

Can a dog pass tetanus on to me?

Although unlikely, it’s possible that tetanus could be transmitted to humans via an animal bite. As tetanus doesn’t really occur in dogs that much, it’s extremely rare that a dog could pass on tetanus to you.

However, it’s best to get any animal bite checked out, as various animals can carry the disease.

Recap

Even though you might already have preconceptions about the terrifying dangers of tetanus, take comfort in the fact it’s really not that common, and it’s likely that you or your dog will never have to experience it.

Your dog has a strong immune system that’s extremely resistant to tetanus, but to be extra safe, if they ever encounter a wound, make sure you keep it clean to prevent the spread of any bacteria.

Sources
  1. Tetanus in the dog: review and a case-report of concurrent tetanus with hiatal hernia Irish Veterinary Journal, 57, (10), Oct 2004, 593-597, doi:10.1186/2046-0481-57-10-593
  2. Risk factors associated with outcome in dogs with tetanus: 38 cases (1987-2005) Journal of American Veterinary Medical Association, 230, (1), Jan 2007, 76-83, doi: 10.2460/javma.230.1.76. PMID: 17199496