parassita

Parassita is an organism that lives in or on another organism, the host, and benefits at the host's expense. The term is used in biology and medicine to describe a wide range of organisms that rely on a host for nutrients, habitat, and/or transmission stages. Parasites can be unicellular or multicellular, and they may cause disease or affect host fitness.

Parasites are typically categorized by their relationship to the host: ectoparasites live on the outside of the host (such as ticks, lice); endoparasites live inside the host's body (such as intestinal worms, protozoa). They can be macroparasites (visible, like worms and arthropods) or microparasites (such as bacteria and viruses). Some parasites have complex life cycles involving one or more secondary hosts or vectors.

Life cycle and transmission: Many parasites reproduce inside the host and release stages that infect new hosts. Transmission routes include direct contact, ingestion of contaminated food or water, vectors such as mosquitoes, and vertical transmission from parent to offspring.

Impact: Parasites influence ecological interactions and population dynamics. In humans and domestic animals, they can cause infectious diseases, anemia, malnutrition, and reduced productivity; in plants, parasitic organisms can decrease crop yields. Economic and health impacts drive veterinary and medical parasitology.

Control and study: Prevention and treatment rely on hygiene, sanitation, vector control, vaccination in some cases, and antiparasitic medications. Diagnosis often uses microscopy, immunoassays, and molecular methods. Research on host-parasite coevolution and parasite life cycles informs control strategies.