What are some parasites that cause serious problems giving people what?

Some parasites that cause serious health issues in humans include Plasmodium species, which cause malaria, and Toxoplasma gondii, linked to flu-like symptoms and severe complications in immunocompromised individuals. Another significant parasite is Giardia lamblia, responsible for giardiasis, leading to gastrointestinal distress. Additionally, the tapeworms from the genus Taenia can cause nutritional deficiencies and other complications. These parasites can lead to serious health problems, including organ damage, chronic illness, and even death if untreated.