**Question:** Drug used for the chemoprophylaxis of leptospirosis is -

A. Doxycycline
B. Ciprofloxacin
C. Azithromycin
D. Ceftriaxone

**Core Concept:** Leptospirosis is a bacterial infection caused by the Leptospira bacteria. It is primarily transmitted through contact with infected animals or contaminated water. Chemoprophylaxis refers to the use of antibiotics to prevent infection in high-risk individuals.

**Why the Correct Answer is Right:** Doxycycline is a tetracycline antibiotic that is effective against Leptospira bacteria. It is often used as a chemoprophylaxis agent due to its broad spectrum of activity and good tissue penetration.

**Why Each Wrong Option is Incorrect:**

A. Ciprofloxacin (Cipro): Ciprofloxacin belongs to the quinolone antibiotic class and is effective against various Gram-negative bacteria. However, it lacks activity against Leptospira, making it an incorrect choice for leptospirosis chemoprophylaxis.

B. Azithromycin: Azithromycin is a macrolide antibiotic used against various Gram-positive and some Gram-negative bacteria. It does not cover Leptospira, rendering it unsuitable for leptospirosis chemoprophylaxis.

C. Ceftriaxone: Ceftriaxone is a third-generation cephalosporin antibiotic used against Gram-negative bacteria but lacks activity against Leptospira, making it an inappropriate choice for leptospirosis chemoprophylaxis.

**Clinical Pearl:** Leptospirosis is a preventable infection, and appropriate chemoprophylaxis like Doxycycline can protect high-risk individuals exposed to the bacterium. Early diagnosis and treatment are crucial for better patient outcomes.

**Correct Answer:** Doxycycline (D) is the recommended drug for leptospirosis chemoprophylaxis due to its activity against Leptospira and its favorable pharmacokinetic properties. However, it is essential to note that Leptospirosis is a zoonotic disease transmitted from animals to humans, often associated with occupational or recreational exposures to contaminated water or soil.