If a horse presents with a laceration on its leg and has a stiff gait, what disease might be suspected?

The suspicion of tetanus in a horse with a laceration and a stiff gait is highly plausible due to the characteristic symptoms associated with this disease. Tetanus, caused by the bacterium Clostridium tetani, often results from wounds or lacerations that allow the bacteria to enter the body. The toxin produced by this bacterium leads to muscle stiffness and spasms, which can manifest as a stiff gait.

In horses, the clinical signs of tetanus include a distinct stiff posture, difficulty in movement, and often a heightened sensitivity to stimuli, which aligns with the observations in this case. The presence of a leg laceration further supports the likelihood of tetanus since it provides a potential entry point for the bacteria.

In contrast, the other conditions listed do not typically present in the same way with the tight association between a recent laceration and a stiff gait caused by the neurotoxin. For example, strangles primarily affects the respiratory system with throat swelling and is not directly linked to stiffness in gait. Laminitis is characterized by pain and shifting weight due to hoof distress rather than stiffness. Navicular disease involves chronic lameness and pain but not the acute stiffness or muscle spasms typical of tetanus. Thus