xenoparasite

xenoparasite

 [zen″o-par´ah-sīt]
an organism not usually parasitic on a particular species, but which becomes so because of a weakened condition of the host.

xen·o·par·a·site

(zen'ō-par'ă-sīt),
An ecoparasite that becomes pathogenic as a consequence of its host's weakened resistance.

xen·o·par·a·site

(zen'ō-par'ă-sīt)
An ecoparasite that becomes pathogenic in consequence of weakened resistance on the part of its host.