## Core Concept
Zoonotic diseases are infections that can be transmitted from animals to humans. These diseases can be caused by bacteria, viruses, fungi, or parasites. The transmission can occur through direct contact with infected animals, contaminated food and water, or vectors like ticks and mosquitoes.

## Why the Correct Answer is Right
The correct answer, Rabies, is indeed a zoonotic disease. It is caused by a virus that is transmitted through the saliva of infected animals, usually through a bite. This virus affects the nervous system of mammals, including humans, and is almost always fatal if not treated promptly.

## Why Each Wrong Option is Incorrect
- **Option A: Leptospirosis** is a zoonotic disease caused by bacteria of the genus *Leptospira*. It is transmitted through the urine of infected animals, often through contaminated water. So, this is indeed a zoonotic disease.
- **Option B: Toxoplasmosis** is caused by the parasite *Toxoplasma gondii*. It can be transmitted to humans through contact with cat feces, contaminated food or water, or from an infected mother to her fetus. Therefore, it is a zoonotic disease.
- **Option D: Plague** is caused by the bacterium *Yersinia pestis*, which is transmitted through the bites of infected fleas that live on rats and other rodents. This makes it a zoonotic disease.

## Clinical Pearl / High-Yield Fact
A key point to remember is that zoonotic diseases often have animal reservoirs and can present with nonspecific symptoms in humans, making diagnosis challenging. Awareness of exposure history (e.g., travel, occupation, animal contact) is crucial for diagnosing zoonotic infections.

**Correct Answer: B. Tetanus**