ascarid, helminth, pinworm, threadworm. parasite on white background

anatomy animal ascariasis ascarid ascaris biology body care danger dangerous design digestive disease evil flatworm health helminth hookworm human hygiene icon illness illustration infecting infection intestinal intestine isolated larva life medical medicine nature nematode parasite parasitic parasitology pinworm round roundworm science sign simple small symbol tapeworm tract vector white worm