**Core Concept**
Ivermectin is an antiparasitic medication used to treat various parasitic infections. It works by inhibiting the functioning of certain parasites.

**Why the Correct Answer is Right**
Ivermectin's mechanism involves binding to glutamate-gated chloride channels in parasites, leading to their paralysis and death. It is commonly used for treating onchocerciasis, strongyloidiasis, and scabies.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect as ivermectin is indeed used for onchocerciasis.
**Option B:** Incorrect as ivermectin is used for strongyloidiasis.
**Option C:** Incorrect as ivermectin is used for scabies.

**Clinical Pearl / High-Yield Fact**
Ivermectin is not typically used for treating bacterial or fungal infections, making it crucial to identify the type of infection before prescribing.

**Correct Answer:** D.