**Core Concept**
Leptospirosis is a bacterial infection caused by Leptospira species, transmitted through contact with contaminated water or soil. Anicteric Leptospirosis refers to the milder form of the disease, characterized by symptoms without jaundice. The clinical features of anicteric Leptospirosis can vary but often include systemic symptoms.

**Why the Correct Answer is Right**
High mortality is not a characteristic feature of anicteric Leptospirosis. Mortality in Leptospirosis is typically associated with the more severe icteric form of the disease, which is characterized by jaundice, renal failure, and respiratory distress. Anicteric Leptospirosis usually has a self-limiting course, with symptoms resolving on their own. The high mortality rate is more commonly seen in icteric Leptospirosis, particularly in cases with severe pulmonary hemorrhage.

**Why Each Wrong Option is Incorrect**
**Option A:** Influenza-like illness, including fever, hepatosplenomegaly, nausea, and headache, can be seen in anicteric Leptospirosis. These symptoms are a result of the body's immune response to the infection.
**Option B:** Muscle pain is a common symptom of anicteric Leptospirosis, often reported by patients. This is due to the inflammatory response to the infection.
**Option D:** Conjunctival suffusion, a condition characterized by conjunctival injection without exudate, is a common finding in anicteric Leptospirosis. It is often used as a diagnostic clue in patients with suspected Leptospirosis.

**Clinical Pearl / High-Yield Fact**
Conjunctival suffusion is a key clinical feature of Leptospirosis, particularly in the anicteric form. It is a distinctive finding that should raise suspicion for Leptospirosis in patients with systemic symptoms.

**✓ Correct Answer: C. High moality**