**Core Concept**
Diverticulitis is a gastrointestinal disorder characterized by inflammation of diverticula, which are small, bulging pouches in the wall of the colon. This condition often arises due to the accumulation of fecal matter within the diverticula, leading to infection and inflammation.

**Why the Correct Answer is Right**
The pathophysiology of diverticulitis involves the formation of diverticula, primarily in the sigmoid colon, due to the weakening of the muscular wall. As feces accumulate within these diverticula, they become a fertile ground for bacterial overgrowth and subsequent infection. The inflammation and infection can lead to complications such as abscess formation, perforation, and peritonitis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because diverticulitis is not primarily caused by a viral infection. While viral infections can contribute to the development of diverticulitis in some cases, the primary cause is still related to the accumulation of fecal matter and bacterial overgrowth.
**Option B:** This option is incorrect because the treatment of diverticulitis does not primarily involve the use of antiviral medications. The management of diverticulitis typically involves antibiotics, bowel rest, and sometimes surgical intervention.
**Option C:** This option is incorrect because the primary location of diverticula formation is not the small intestine. Diverticula are most commonly found in the sigmoid colon.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that patients with diverticulitis often present with symptoms such as left lower quadrant abdominal pain, fever, and changes in bowel habits. The diagnosis of diverticulitis can be challenging, and a high index of suspicion is necessary to avoid missing this condition.

**Correct Answer: D.**