**Core Concept**
Guinea worm prophylaxis involves measures to prevent the transmission and spread of Dracunculus medinensis, a parasitic worm that causes dracunculiasis. The primary goal is to break the life cycle of the worm by reducing human exposure to contaminated water sources.

**Why the Correct Answer is Right**
To prevent Guinea worm disease, several measures are taken:
- **Water treatment**: Contaminated water sources are treated with disinfectants or filtered to remove the copepods (water fleas) that act as intermediate hosts for the worm.
- **Education and awareness**: Communities are educated about the risks of Guinea worm disease and the importance of avoiding contaminated water sources.
- **Screening and surveillance**: People are screened for symptoms of the disease, and surveillance is conducted to detect and contain outbreaks.

**Why Each Wrong Option is Incorrect**
- **Option A:** is actually a correct measure in Guinea worm prophylaxis. **Water treatment** is essential to prevent the transmission of the disease.
- **Option B:** is also a correct measure. **Education and awareness** are crucial in preventing the spread of the disease, especially in endemic areas.
- **Option C:** is a correct measure as well. **Screening and surveillance** are necessary to detect and contain outbreaks of Guinea worm disease.

**Clinical Pearl / High-Yield Fact**
A key aspect of Guinea worm prophylaxis is the use of **contaminated water source mapping** to identify areas where the disease is most prevalent. This information is used to target interventions and education efforts.

**Correct Answer: D.**