Tetanus & Equine Strangles > The facts

Tetanus is an often fatal bacterial disease caused by a toxin produced by the organism Clostridium tetani. The bacteria is found in soil and droppings and is present all over the world. The bacterial spores can survive in the environment for long periods of time and although harmless in the ground, when bacteria enter the body through wounds in the skin, severe illness can occur. The tetanus bacteria do not need oxygen to survive so they multiply rapidly in the damaged tissues at the injury site.

All grazing animals are susceptible to the toxins produced by Clostridium tetani especially after standard management practices such as castration, dehorning, calving, wounds and dentals. Likewise, tetanus is also often seen in working and hunting dogs that are commonly wounded or may have grass seed abscesses.

Of all animals, horses are particularly sensitive.  Once the bacteria is inside a wound and if the conditions are favourable (ie. reduced tissue oxygenation), the spores germinate and produce a powerful toxin that affects the central nervous system. The toxin causes spasmodic contractions of the muscles and death often comes from respiratory failure. Most commonly, symptoms appear approximately 10d after the injury but there can be a delay of several weeks.

Tetanus attacks the animal’s central nervous system with signs starting out as being as simple as a change in way your animal’s moves and stands at rest to progressive muscle stiffness, spasms, convulsions, recumbency and death. Initial signs in most animals include:

  • Tail may be stiff and stand straight out
  • Ears stand erect and skin may bunch together across the forehead
  • Rigid muscles with a classical ‘saw-horse’ stance
  • Eating difficulties
  • Anxious facial expression caused by facial muscle stiffness
  • Hypersensitivity to noise and light
  • Third eyelid protrusion

If diagnosed early, animals may be treated with intensive care hospitalisation, large doses of antibiotics and tetanus antitoxin injections. Dogs have a reasonable survival rate when detected early due to their easier ability to hospitalise. Treatment is demanding and highly costly and some owners are faced with having to euthanase their animals, particularly horses, on humane grounds. 

Tetanus is an easily prevented disease in all animal species. Vaccinations can be administered by a veterinarian or yourself and are very simple to give (more info in the table below). 

Strangles is a serious and highly contagious respiratory disease of horses and donkeys caused by the bacterium Streptococcus equi equi. Strangles commonly affects foals and younger horses, however, horses of any age can be infected.

Infection occurs when susceptible horses have direct contact with infected horses through coughing or eating and drinking from a source contaminated by a sick horse. Infection can also be spread by indirect contact with things infected horses have contaminated such as stables, bedding, feed and water buckets, vehicles, hands and clothing. Outbreaks can occur when large numbers of horses are held in close contact.

Strangles affects the upper respiratory system and lymph nodes of the head. Signs of disease include:

  • Depression and fever within 3-8 days of becoming infected
  • Lack of appetite and painful swallowing due to throat inflammation
  • Swollen and painful lymph nodes, especially those of the head
  • Burst lymph nodes that discharge thick creamy yellow pus
  • Breathing difficulties, nasal discharge and a cough
  • Occasionally infection may spread to other parts of the body (‘bastard strangles’) – this form is very difficult to cure and is often fatal

Signs may persist for days to months depending on how many lymph nodes are affected.

Yes. Affected horses remain infectious for at least four weeks after clinical signs have disappeared. Some horses may even retain the infection in the guttural pouch and shed bacteria intermittently for months afterwards.

Diagnosis is based on clinical signs as listed above. Often your veterinarian will collect swab samples from the nose and/or abscesses and send them to a laboratory for bacterial culture.

Strangles is a very painful disease and veterinary treatment should be sought immediately to alleviate the symptoms. Anti-inflammatory medications are often given and then an assessment is made as to whether antibiotics are required or not. Transportation should be limited as this is stressful for the sick horse and also risks spreading the disease.

All affected horses should be isolated for 6-8wks following the onset of signs to prevent spread to other horses. Strict hygiene practices should be implemented on the property and all areas where sick horses have been held should be disinfected as soon as possible. The strangles bacterium is very hardy and can remain active in the environment for weeks to months in moist conditions.

Vaccination > Regular vaccinations can help avoid contracting strangles and also aid in control of outbreaks. Vaccinations are recommended for any horses that go to shows, competitions, studs or those agisted with other unknown horses. Vaccination is not 100% but will significantly reduce the severity of disease should your horse contract the disease. Strangles vaccination can be given combined with tetanus vaccination (Equivac 2in1).

Events > There is always a risk of infection if you are sharing water sources, feed bins, tack and grooming gear at horse events. Always use your own equipment and thoroughly clean your boots and outer clothing after each event. 

New Horses > If new horses are being introduced to a property without having up to date vaccinations, they should ideally be quarantined for two weeks away from all other horses. This will allow for close monitoring for any signs of ill health. 

Boundary Fences > Nose-to-nose contact between your horses and those on neighbouring properties can be a source of infection. Manage this risk by keeping horses away from boundary fences or use double fencing.

Below is a list of common vaccines for horses that will protect against tetanus +/- strangles. If you wish to vaccinate your dogs against tetanus, please speak to your local veterinarian for advice.

Mares should receive their annual booster 1-2m prior to foaling to ensure high antibody levels in colostrum to protect foal for the first 2-3m of its life (foals from vaccinated mothers = vaccinate from 3m of age, foals from unvaccinated mothers = tetanus anti-toxin at birth, vaccinate from 6wks of age).

This information sheet is not intended as a substitute for a veterinary consultation.
It is recommended that a consultation be arranged with a veterinary practitioner if you have any concerns with your pet’s health.

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