Macroparasites are parasites that are large enough to be seen with the naked eye, in contrast to
microparasites. They grow in one
host but reproduce by infective stages outside this host. These generally include
ticks,
mites,
helminths (
nematodes,
flatworms, etc.), and can be either external parasites (
ectoparasitic) or internal parasites (
endoparasitic). The most abundant macroparasite in humans is the nematode
Ascaris lumbricoides which causes an infection called
ascariasis. Macroparasites are also parasitic of many plant species and can be a significant agricultural pest.