Cutaneous leishmaniasis (also known as oriental sore, tropical sore, chiclero ulcer, chiclero's ulcer or Aleppo boil, '''Delhi Boil''') is the most common form of leishmaniasis affecting humans. It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sandfly.

Cutaneous leishmaniasis is the most common form of leishmaniasis affecting humans.[4] It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sandfly. There are about twenty species of Leishmania that may cause cutaneous leishmaniasis.
Other names
Oriental sore, Tropical sore, Chiclero ulcer, Chiclero's ulcer, Aleppo boil, Delhi Boil or Desert boil.
This disease is considered to be a zoonosis (an infectious disease that is naturally transmissible from animals to humans), with the exception of Leishmania tropica — which is often an anthroponotic disease (an infectious disease that is naturally transmissible from humans to vertebrate animals)

Oriental sore disease, also known as cutaneous leishmaniasis, is caused by the parasite Leishmania tropica. Leishmania tropica is a species of Leishmania that is primarily transmitted to humans through the bite of infected sand flies.

Here's a detailed explanation of each option and why Leishmania tropica is the correct answer:

a) Leishmania tropica:
- Leishmania tropica is the causative agent of oriental sore disease, also known as Old World cutaneous leishmaniasis.
- It is primarily found in the Eastern Mediterranean region, including countries like Iran, Iraq, Syria, Saudi Arabia, and Pakistan.
- The disease manifests as skin lesions, typically on exposed body parts such as the face, arms, and legs. The lesions can be painless or mildly painful and may have an ulcer-like appearance.
- The sand fly species Phlebotomus sergenti is the main vector for transmitting L. tropica to humans.

b) L. donovani:
- Leishmania donovani is the causative agent of visceral leishmaniasis, also known as kala-azar.
- Visceral leishmaniasis primarily affects the internal organs, such as the spleen, liver, and bone marrow.
- It is prevalent in regions like India, Bangladesh, Sudan, and Brazil.
- The sand fly species Phlebotomus argentipes is the main vector for transmitting L. donovani to humans.

c) L. brasiliensis:
- Leishmania brasiliensis is the causative agent of New World cutaneous leishmaniasis, also known as American cutaneous leishmaniasis.
- It is primarily found in Central and South America, including countries like Brazil, Colombia, and Peru.
- The disease manifests as skin ulcers, typically on exposed body parts, and can cause disfigurement if left untreated.
- The sand fly species Lutzomyia is the main vector for transmitting L. brasiliensis to humans.

d) Phlebotomus intermedius:
- Phlebotomus intermedius is a species of sand fly that is not directly responsible for causing any specific disease.
- Sand flies of the genus Phlebotomus are known to transmit Leishmania parasites, including L. tropica, L. donovani, and L. brasiliensis.
- However, in the context of oriental sore disease, the main vector is Phlebotomus sergenti, not Phlebotomus intermedius.

In conclusion, oriental sore disease in humans is caused by Leishmania tropica, which is primarily transmitted by the sand fly species Phlebotomus sergenti.