In occult filariasis microfilaria are present in ?
**Core Concept**
Occult filariasis is a condition where there is evidence of past or present infection with Wuchereria bancrofti or Brugia malayi, but no microfilariae are detectable in the peripheral blood. This is due to the absence of nocturnal peaks in microfilariae circulation, which makes detection challenging.
**Why the Correct Answer is Right**
The correct answer is based on the pathophysiology of occult filariasis. In this condition, the microfilariae are present in the body but are not circulating in the peripheral blood due to the absence of nocturnal peaks. This is often due to the development of a strong immune response against the microfilariae, which causes them to be sequestered in various tissues such as the lungs, liver, and spleen. The microfilariae can be detected in these tissues, making them the site of their presence in occult filariasis.
**Why Each Wrong Option is Incorrect**
* **Option A:** Not relevant to occult filariasis, as it is not a condition where microfilariae are absent from the peripheral blood.
* **Option B:** Incorrect, as it is not a specific tissue where microfilariae are typically found in occult filariasis.
* **Option C:** Incorrect, as it is not a condition where microfilariae are present in the body but not in the peripheral blood.
**Clinical Pearl / High-Yield Fact**
In occult filariasis, the presence of microfilariae in tissues can be detected through techniques such as lymph node biopsy or splenic puncture, which can aid in diagnosis.
**Correct Answer: D. Tissues.