Which organism is primarily responsible for cysticercosis in humans?

Cysticercosis in humans is primarily caused by the larval stages of Taenia solium, a type of tapeworm commonly found in pigs. When humans ingest the eggs of Taenia solium, often through contaminated food or water, these eggs can develop into larvae which then invade the tissues, leading to the formation of cysts. This disease can cause serious neurological issues if the cysts form in the brain, resulting in a condition known as neurocysticercosis.

In contrast, Hymenolepis nana is known to cause hymenolepiasis, Taenia saginata is associated with beef tapeworm infections, and Ascaris lumbricoides is known for causing ascariasis, which is a different type of parasitic infection. Therefore, while the other organisms are infectious agents, they do not lead to cysticercosis, highlighting Taenia solium as the specific causative agent for this condition.