Tetanus is caused by Clostridium tetani, a bacterium that resides in the soil. The organism lives in anaerobic environments (environments with no oxygen). It gains access to the horse’s system by colonizing an infected wound, especially deep and infected puncture wounds. There it produces an extremely potent toxin which affects specific (inhibitory) nerve endings in the spinal cord, causing constant muscle contraction of the main muscle groups.
Affected horses generally (not always) have a history of a wound. Their limbs appear stiff, their third eyelids cover their eyes. Their ears are typically erect, tails raised and nostrils flared. They rapidly reach a point where they cannot rise, and they lie on their side, with their limbs rigid.
Tetanus is well known for causing what appear to be seizures, brought on by loud noises. Beyond this classic appearance of affected horses, there are no diagnostic tests to confirm a diagnosis.
Vets “back into a diagnosis” of tetanus by ruling out other causes and by knowing that the horse has not been vaccinated for it. Horses with the third eyelid covering the eyes are tetanus cases until proven otherwise.
Treatment involves supportive nursing care, antibiotics, local wound care, and tetanus antitoxin. In some cases, vaccination may also be performed in the face of disease, but this is case dependent and depends on vaccination status.
Other Diagnoses Considered
Treatments May Include
Prognosis & Relevant Factors
Once an unvaccinated horse has clear signs of tetanus, the prognosis is poor.
I Might ObserveRelated Observations
QUESTIONS TO ASK MY VET
Helpful Terms & Topics in HSVGWritten, Reviewed or Shared by Experts in Equine Health
Helpful Outside ResourcesCredible Equine Health Information on the Internet