Parasites

Living beings that live completely (obligatory parasites) or partially (optional parasites), permanently (stationary parasites) or temporarily (temporary parasites) at the expense of other species.

Parasites can:

• on the surface as ectoparasites (arachnids, insects)
• or perhaps
• within the host as endoparasites

live. Endoparasites are further divided into unicellular prtozoa and multicellular worms (helminths).

Parasites living on the skin are also called dermatozoa.

End host: In this host, sexual reproduction of protozoa takes place. In helminths, the parasite reaches sexual maturity, adult worms appear which produce sexual reproduction stages (unice, microfilariae).

Intermediate host: Here the parasite reproduces asexually or only matures. In helminths, intermediate or larval stages may occur.

Primary host: Preferred host of the parasite. In this host an optimal reproduction takes place.

Secondary host: Possible host of the parasite, but which does not provide optimal living conditions (e.g. human for trichinae)

Loss of host: The parasite does not develop completely (dead end)

Before parasites can be successfully introduced after an infection, the parasite must be sexually (e.g. worm eggs) or asexually (e.g. malaria trophozoites) infected in the host.