Mucocutaneous leishmaniasis is caused by:
**Core Concept**
Mucocutaneous leishmaniasis is a rare and severe form of cutaneous leishmaniasis, characterized by the spread of the disease from the skin to mucous membranes, primarily in the nasal passages, lips, and oral cavity. This condition is caused by certain species of the Leishmania parasite.
**Why the Correct Answer is Right**
The correct answer is **Leishmania braziliensis**. This species is known for its ability to cause mucocutaneous leishmaniasis, a more severe form of the disease compared to cutaneous leishmaniasis. The parasite invades the mucous membranes, leading to symptoms such as nasal discharge, lip lesions, and oral ulcers. The pathogenesis involves the parasite's ability to evade the host's immune system and cause tissue damage through the release of various enzymes and cytokines.
**Why Each Wrong Option is Incorrect**
**Option A:** Leishmania major is primarily responsible for causing cutaneous leishmaniasis in the Middle East and North Africa, but it does not typically cause mucocutaneous leishmaniasis.
**Option B:** Leishmania donovani is the main cause of visceral leishmaniasis, which affects the internal organs such as the spleen, liver, and bone marrow, but not typically the mucous membranes.
**Option C:** Leishmania tropica is another species that causes cutaneous leishmaniasis, but it is not associated with mucocutaneous leishmaniasis.
**Clinical Pearl / High-Yield Fact**
Mucocutaneous leishmaniasis is often referred to as "espundia" in South America, where it is endemic. This term is derived from the Spanish word for "spreading disease," due to the parasite's ability to spread from the skin to mucous membranes.
**Correct Answer:** C.