Which parasite resides in the liver and is responsible for hydatid cysts?

Echinococcus granulosus is the parasite that resides in the liver and is primarily responsible for the formation of hydatid cysts. This small tapeworm's lifecycle includes definitive hosts, usually canines, and intermediate hosts, such as sheep or humans. When humans ingest the eggs of Echinococcus granulosus, often through contaminated food or water, the larvae can migrate to the liver and develop into hydatid cysts, which can significantly impact liver function and may lead to serious health complications if not diagnosed and managed appropriately.

The presence of hydatid cysts is a key characteristic of infections caused by this parasite. These cysts can grow and cause pressure on surrounding tissues, leading to symptoms. If not treated, hydatid disease can result in severe liver issues, rupture of the cysts, and anaphylactic reactions.

In contrast, the other choices represent different types of parasites with distinct characteristics and life cycles. Giardia intestinalis is a protozoan that primarily causes gastrointestinal infections rather than liver cysts, Ascaris lumbricoides is a large roundworm that causes ascariasis and affects the intestines, and Taenia solium, while a tapeworm like Echinococcus, is known for causing cysticerc