organismid, kes (mis) elavad teistes organismides (endoparasitism) või nende pinnal (ektoparasitism) ja kasutavad nende koostis- või toitaineid
an organism (plant or animal) that lives in or on another living organism of a different kind and derives subsistence from it without returning any benefit
Exception will be made in the specific case of defined gene-for-gene relationships between parasite or symbiont and host, and where both organisms are to be conserved.