parasitization

Parasitization refers to the process by which a parasite establishes and maintains an association with a host from which it derives resources, such as nutrients, tissues, or space. It is a component of the broader relationship called parasitism, in which a parasite benefits at the expense of the host. The term emphasizes the dynamic interaction, such as how the parasite locates, attaches to or invades, and exploits the host over time, rather than the outcome alone.

Parasitization occurs across taxa and includes endoparasitism, where parasites inhabit the host's body, and ectoparasitism, where they live on the exterior. Many parasitizing organisms are adapted to specific hosts, life stages, or tissues and may manipulate host physiology or behavior to facilitate feeding and reproduction. Plant parasitization is also common, with parasitic plants deriving water or nutrients from hosts via specialized structures such as haustoria.

The process typically involves host selection, attachment or invasion, feeding, and development within or on the host. Hosts mount defenses, including immune responses and behavioral changes, while parasites evolve countermeasures to evade defenses, endure environmental conditions, and complete their life cycles. The consequences range from subclinical effects to disease, reduced fitness, or death, influencing population dynamics and ecosystem interactions.

Examples include animal parasites such as nematodes, protozoa, ticks, and lice; parasitoid wasps whose larvae develop inside hosts; and plant parasites like mistletoe or dodder. Controlling parasitization is important in medicine, agriculture, and wildlife management, often involving sanitation, resistant varieties, targeted therapies, or biological control strategies.