In
biology/
ecology,
parasitism is a non-mutual
symbiotic relationship between
species, where one species, the
parasite, benefits at the expense of the other, the
host. Traditionally
parasite (in biological usage) referred primarily to organisms visible to the naked eye, or
macroparasites (such as
helminths).
Parasite can include
microparasites, which are typically smaller, such as
protozoa,
viruses, and
bacteria. Examples of parasites include the plants
mistletoe and
cuscuta, and animals such as
hookworms.
