Cysticercus cellulosae seen in
**Core Concept**
Cysticercus cellulosae is the larval stage of the pork tapeworm (Taenia solium), a parasitic flatworm. It is a key component of the life cycle of this organism, which can cause cysticercosis in humans.
**Why the Correct Answer is Right**
Cysticercus cellulosae is formed when the eggs of Taenia solium are ingested, typically through contaminated food or water. The eggs hatch into oncospheres, which penetrate the intestinal wall and migrate to various parts of the body, where they develop into cysticerci. The cysticerci can then mature into adult tapeworms, which live in the small intestine.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because cysticercus cellulosae is specific to Taenia solium, not to other parasites like Echinococcus granulosus or Hymenolepis nana.
**Option B:** This is incorrect because cysticercus cellulosae is not typically associated with the skin, but rather with internal organs like the brain, muscle, and liver.
**Option C:** This is incorrect because cysticercus cellulosae is not a stage of the life cycle of Toxocara cati, which is a different type of parasitic worm.
**Clinical Pearl / High-Yield Fact**
Cysticercosis, caused by Cysticercus cellulosae, can manifest with a wide range of symptoms, including headaches, seizures, and muscle weakness, depending on the location of the cysts in the body.
**Correct Answer:** D.