Carrion’s disease is caused by:
**Core Concept**
Carrion's disease is a zoonotic disease caused by a bacterium transmitted through the bite of an infected sandfly. It presents with two distinct phases: an initial febrile phase and a secondary phase characterized by severe anemia, jaundice, and hemorrhaging.
**Why the Correct Answer is Right**
The bacterium responsible for Carrion's disease is *Bartonella bacilliformis*. This bacterium is transmitted to humans through the bite of an infected *Lutzomyia* sandfly. Upon entry, the bacteria multiply in the skin, causing the initial febrile phase. Later, they infect red blood cells, leading to severe anemia, jaundice, and hemorrhaging.
**Why Each Wrong Option is Incorrect**
**Option A:** *Trypanosoma cruzi*, the causative agent of Chagas disease, is transmitted by a triatomine bug, not a sandfly.
**Option B:** *Plasmodium falciparum*, the parasite causing malaria, is transmitted through the bite of an infected *Anopheles* mosquito.
**Option C:** *Leishmania* species, causing leishmaniasis, are also transmitted by sandflies but result in a different clinical presentation.
**Clinical Pearl / High-Yield Fact**
Carrion's disease is also known as Oroya fever and Verruga peruana, reflecting its distinct clinical phases.
**Correct Answer:** C. *Bartonella bacilliformis*.