parasitas

Parasitas are organisms that live on or inside another organism (the host) from which they obtain nutrients, often to the host's detriment. They can be endoparasites that inhabit internal organs or tissues, or ectoparasites that live on the body surface. Parasites may be unicellular or multicellular and include major groups such as protozoa, helminths, and ectoparasites.

Many parasites have life cycles that require one or more hosts or vectors; some are directly transmitted between hosts. Transmission occurs through contaminated food or water, poor hygiene, soil contact, or bites from infected vectors such as insects. Host factors, including age and immunity, influence disease severity.

Clinical effects range from asymptomatic carriage to severe illness. Common diseases caused by parasites include malaria, giardiasis, amoebiasis, schistosomiasis, taeniasis, and filariasis. Diagnosis typically relies on microscopy, antigen or molecular tests, and serology.

Treatment depends on the parasite and may involve antiparasitic drugs such as metronidazole, albendazole, praziquantel, or artemisinin-based therapies, often with supportive care. Prevention emphasizes sanitation, safe drinking water, proper food handling, vector control, bed nets, and health education.

Parasitos is derived from the Greek parasitos, meaning "one who eats at the table of another." In public health, parasites contribute to a range of neglected tropical diseases, particularly in low-resource settings.