**Question:** A 21-year-old man presents with symptoms of headache, fever, chills, and discomfort in both sides of his jaw. He has also noticed discomfort in his testes, but no dysuria or urethral discharge. Physical examination reveals bilateral enlargement of the parotid glands, as well as bilateral testicular enlargement and tenderness on palpation. His temperature is 38.5°C, pulse rate of 92/min, and the remaining examination is normal. Laboratory data show hemoglobin 15 g/dL; hematocrit 40%; WBC 12000/mL, with 30% segmented neutrophils, 8% monocytes, and 62% lymphocytes. Which of the following statements concerning this disease is true?

A. This patient has acute bacterial prostatitis.
B. This patient has mumps.
C. This patient has epididymitis.
D. This patient has viral hepatitis.

**Correct Answer:**

**Core Concept:** Mumps is a viral infection caused by the parotid gland-targeting Morbillivirus, which is part of the Paramyxoviridae family. It primarily affects children and young adults and can lead to complications like orchitis, epididymitis, meningitis, pancreatitis, and oophoritis in females.

**Core Concept (Expanded):** Mumps is a viral infection caused by the Morbillivirus. It primarily targets the salivary glands, specifically the parotid glands, leading to the characteristic swelling. The virus can spread to other organs like testes, epididymis, and ovaries, which is why the patient may experience symptoms in these areas as well.

**Why the Correct Answer is Right:**

The correct answer, B, is due to the patient presenting with symptoms consistent with Mumps infection. These symptoms include:

1. Headache and fever, which are common signs of viral infections.
2. Pain in the parotid gland (Salivary gland) region, which is typical of Mumps.
3. Pain in the testes, epididymis, and ovaries, which are affected due to the virus's ability to spread to these organs.

**Why Other Answers are Incorrect:**

A and C are incorrect because Mumps primarily affects the salivary glands and does not typically cause inflammation of the prostate (orchitis) or epididymitis.

D is incorrect because viral hepatitis is caused by hepatitis viruses and presents with different symptoms, like jaundice, hepatomegaly, and elevated liver enzymes, which are not present in the given case.

In conclusion, the correct answer, B, is chosen due to the patient's symptoms and the virus's ability to spread to the testes, epididymis, and ovaries, which are the primary target organs of Mumps. The other options are incorrect because Mumps primarily affects the salivary glands and does not typically cause inflammation of the prostate or epididymis, or present with elevated liver enzymes, which are not mentioned in the case description.