The true statement regarding tetanus is –
**Core Concept**
Tetanus is a bacterial infection caused by *Clostridium tetani*, characterized by muscle rigidity and spasms due to the production of tetanospasmin, a potent neurotoxin. The toxin blocks the release of neurotransmitters, specifically glycine and GABA, which are inhibitory neurotransmitters in the spinal cord and brain.
**Why the Correct Answer is Right**
Tetanospasmin, the primary neurotoxin responsible for tetanus, acts by binding to the presynaptic terminal of inhibitory neurons, preventing the release of glycine and GABA. This leads to an overactive state of the nervous system, resulting in muscle rigidity, spasms, and rigidity. The toxin's mechanism of action is due to its ability to block the inhibitory neurotransmitters, leading to an imbalance in the excitatory and inhibitory neurotransmitter systems.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because tetanus is not caused by a viral infection, but rather by the bacterial toxin produced by *Clostridium tetani*.
* **Option B:** This option is incorrect because the toxin does not directly stimulate the release of acetylcholine, but rather blocks the release of inhibitory neurotransmitters.
* **Option C:** This option is incorrect because the toxin does not directly affect the peripheral nervous system, but rather acts centrally in the spinal cord and brain.
**Clinical Pearl / High-Yield Fact**
It is essential to note that tetanus is a medical emergency that requires prompt treatment with tetanus immunoglobulin and wound care to prevent the spread of the toxin.
**Correct Answer: C. The toxin acts centrally in the spinal cord and brain to produce muscle rigidity and spasms.**