**Question:** Boutonneuse fever is caused by -

A. Rickettsia conorii
B. Plasmodium species
C. Leptospira species
D. Dengue virus

**Correct Answer:** B. Plasmodium species

**Core Concept:** Boutonneuse fever is a type of arboviral infection (arthritis-borne viral disease) caused by the bite of an infected mosquito carrying the pathogen. Arboviral infections are characterized by acute onset fever, headache, and joint pains.

**Why the Correct Answer is Right:** Boutonneuse fever is primarily caused by Plasmodium species, which includes Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum. These parasites are transmitted to humans through the bite of infected Anopheles mosquitoes. The correct answer is not Dengue virus (D), as Dengue fever is caused by the Dengue virus, not a parasite.

**Why Each Wrong Option is Incorrect:**

A. Rickettsia conorii (Option A) is responsible for another arboviral infection called Crimean-Congo hemorrhagic fever, not Boutonneuse fever.

C. Leptospira species (Option C) are responsible for Leptospirosis, another arboviral infection transmitted through contaminated water.

**Clinical Pearl:** Boutonneuse fever and Dengue fever are both transmitted by mosquitoes, but they are caused by different pathogens. Understanding the specific pathogens can help in appropriate diagnosis and treatment strategies for these diseases.

**Correct Answer Explanation:**

Boutonneuse fever is caused by Plasmodium species, which are responsible for malaria. The infection leads to the development of malaria-like symptoms, including fever, headache, joint pains, and sometimes severe complications such as cerebral malaria and acute kidney failure. The correct answer (Option B) is related to the specific pathogen causing Boutonneuse fever, while incorrect options (A, C, and D) represent other infections caused by different pathogens. Understanding the distinction between these diseases is crucial for accurate diagnosis and treatment of patients presenting with similar symptoms.