Kallu a 30 year old man, presented with subcutaneous itchy nodules over the left iliac crest. On examination they are firm, non tender and mobile. Skin scrapping contains microfilaria and adults worms of-
**Core Concept**
The question is testing the student's knowledge of a specific parasitic infection that causes subcutaneous nodules with microfilariae and adult worms present in skin scrapings. This condition is characterized by a cutaneous manifestation of a filarial infection.
**Why the Correct Answer is Right**
The correct answer is likely Onchocerca volvulus, the causative agent of onchocerciasis or river blindness. The adult worms of O. volvulus are found in the subcutaneous tissue, particularly around the iliac crest, and the microfilariae are present in the skin scrapings. The presence of microfilariae and adult worms in the skin scrapings is a diagnostic feature of onchocerciasis. The firm, non-tender, and mobile nature of the nodules is consistent with the subcutaneous location of the adult worms.
**Why Each Wrong Option is Incorrect**
**Option A:** Wuchereria bancrofti is another filarial parasite, but it is primarily associated with lymphatic filariasis and does not typically cause subcutaneous nodules.
**Option B:** Loa loa is a filarial parasite that causes loiasis, but it is associated with Calabar swellings, which are different from the subcutaneous nodules described in the question.
**Option C:** Mansonella perstans is a filarial parasite that causes mansonelliasis, but it is not typically associated with subcutaneous nodules or skin scrapings containing microfilariae and adult worms.
**Clinical Pearl / High-Yield Fact**
The presence of microfilariae in skin scrapings is a diagnostic feature of onchocerciasis, but it is essential to note that the microfilariae in the skin scrapings are not necessarily a direct sign of the disease, as they can be present in asymptomatic individuals.
**Correct Answer:** C. Onchocerca volvulus