Which of the following occurs only in humans?

Options

A. Rabies
B. Malaria
C. Anthrax
D. Mumps

Answer

To solve the question "Which of the following occurs only in humans?" we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Rabies**:
- Rabies is caused by the rabies virus, which is typically transmitted through the saliva of infected animals, particularly dogs.
- Symptoms include fever, phobia, and paralysis.
- Rabies can affect both humans and animals.

**Hint**: Consider the transmission method and host organisms for rabies.

2. **Analyzing Malaria**:
- Malaria is caused by the Plasmodium parasite and is transmitted by female Anopheles mosquitoes.
- This disease affects both humans and various animal species.

**Hint**: Look at the vector and host range for malaria.

3. **Examining Anthrax**:
- Anthrax is a bacterial disease caused by Bacillus anthracis.
- It primarily affects animals, particularly herbivores, and is rare in humans.

**Hint**: Identify the primary hosts for anthrax.

4. **Evaluating Mumps**:
- Mumps is a viral infection that causes swelling of the salivary glands.
- This disease occurs exclusively in humans, as animals do not exhibit this condition due to their immune response.

**Hint**: Focus on the specificity of the disease to humans.

### Conclusion:
Based on the analysis, the disease that occurs only in humans is **mumps**.

### Final Answer:
**Mumps** occurs only in humans.