In infections with Taenia solium, which role can humans serve?

Humans can serve as both the definitive and intermediate host in infections with Taenia solium, also known as the pork tapeworm. In this context, when humans ingest the cysticerci (larval stage) from undercooked pork, they become the definitive host. In this stage, the adult tapeworm resides in the human intestines, where it can mature and reproduce.

Additionally, if humans accidentally ingest eggs of T. solium, they can serve as an intermediate host. This occurs when the eggs hatch and the larval stage, cysticerci, migrates to tissues (such as muscles or the central nervous system), leading to a condition known as cysticercosis. In this scenario, the lifecycle involves the larvae developing within human tissues rather than developing into an adult tapeworm in the intestines.

This dual role of humans underscores the complex relationship between the parasite and its host, illustrating how the same organism can complete different stages of its lifecycle depending on how humans are infected.