**Core Concept**
Vibrio cholerae infection causes a secretory diarrhea due to the production of cholera toxin, which activates the adenylate cyclase pathway in the intestinal epithelial cells, leading to an increase in cyclic AMP (cAMP). This results in the secretion of chloride and bicarbonate ions into the intestinal lumen, causing a massive loss of fluids and electrolytes.

**Why the Correct Answer is Right**
The correct answer is Neutrophilia. This is because Vibrio cholerae infection causes a mild inflammatory response in the intestines, which leads to an increase in neutrophil count in the peripheral blood. Neutrophilia is a common finding in patients with cholera, although it is not a specific diagnostic criterion. The neutrophilia is thought to be due to the release of cytokines and other inflammatory mediators in response to the infection.

**Why Each Wrong Option is Incorrect**
**Option A:** Abdominal pain is not a characteristic feature of cholera. Patients with cholera typically present with a history of watery diarrhea, often described as "rice-water" stool, without significant abdominal pain.

**Option B:** The presence of leukocytes in stool is not a typical finding in cholera. In fact, the stool is often described as "sterile" due to the rapid onset of diarrhea and the lack of significant bacterial overgrowth in the gut.

**Option C:** Fever is not a typical presenting feature of cholera. Patients with cholera often present with a history of watery diarrhea and mild abdominal cramps, but fever is not a common finding.

**Clinical Pearl / High-Yield Fact**
It's worth noting that the presence of blood in the stool (hematochezia) is not a typical feature of cholera. If a patient with suspected cholera presents with blood in the stool, it may indicate a different diagnosis, such as a bacterial or parasitic infection.

**✓ Correct Answer: D. Neutrophilia**