Helminths are metazoal (multicellular), worm-like parasites. They are classified into three phyla: thorny-headed worms (Acanthocephala), which are less relevant to humans, roundworms (Nematoda) and flatworms (Platyhelminthes). The latter have two classes: flukes (Trematoda) and tapeworms (Cestoda). The worms cause helminthiasis; the symptoms depend on the type of worm eliciting the disease.
The main transmission path is direct or indirect contact with contaminated persons or objects.
For a successful inactivation of parasites, specific disinfectants effective against parasites are required.