The cystic form of all are seen in man except ?
**Core Concept**
The question is testing the knowledge of the cystic form of certain parasites and their ability to infect humans. The cystic form is a resting stage that allows the parasite to survive outside a host. Different parasites have varying abilities to form cysts and infect humans.
**Why the Correct Answer is Right**
The correct answer is likely one of the parasites that does not form cysts in its life cycle or is not typically infective to humans in its cystic form. For example, the adult stage of the Strongyloides stercoralis is infective to humans, but the larvae can also autoinfect the host, leading to a cycle of reinfection.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the cystic form of *Taenia solium* is a well-known cause of neurocysticercosis in humans.
**Option B:** This option is incorrect because the cystic form of *Echinococcus granulosus* is a common cause of hydatid disease in humans.
**Option C:** This option is incorrect because the cystic form of *Toxoplasma gondii* is a common cause of toxoplasmosis in humans.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the cystic form of certain parasites can be a diagnostic challenge, and a high index of suspicion is required to identify these infections in patients.
**Correct Answer:** D.