**Core Concept**
Measles is a viral infection caused by the measles virus (Morbillivirus), a member of the Paramyxoviridae family. The measles virus is highly contagious and spreads through respiratory droplets, leading to a characteristic rash, fever, and respiratory symptoms.

**Why the Correct Answer is Right**
Measles is the only one among the options that is not typically treated with antibiotics. This is because measles is a viral infection, and antibiotics are ineffective against viruses. In contrast, the other options (Typhoid, Hepatitis B, and Gonorrhea) are bacterial infections that can be treated with antibiotics. Measles treatment focuses on supportive care, such as hydration and antipyretics to manage symptoms.

**Why Each Wrong Option is Incorrect**
**Option B:** Typhoid is a bacterial infection caused by Salmonella Typhi, which is treated with antibiotics such as ceftriaxone or ciprofloxacin.
**Option C:** Hepatitis B is a viral infection, but it is often treated with antiviral medications such as lamivudine or tenofovir, in addition to supportive care.
**Option D:** Gonorrhea is a bacterial infection caused by Neisseria gonorrhoeae, which is typically treated with antibiotics such as ceftriaxone or azithromycin.

**Clinical Pearl / High-Yield Fact**
When differentiating between bacterial and viral infections, remember that antibiotics are ineffective against viruses, and their use can even lead to antibiotic resistance and adverse effects.

**✓ Correct Answer: A. Measles**