General description of the egg and oncosphere of Echinococcus spp. An oncosphere is the larval form of a tapeworm once it has been ingested by an intermediate host animal.

The oncosphere, containing three pairs of hooks, is encased in an inner envelope that is surrounded by another membranous structure, the embryophore. A cellular zone known as the outer envelope lies between the embryophore and the shell (or capsule) , usually the outermost covering of the egg.

This embryo characteristically possesses three pairs of hooks. The hexacanth may or may not be surrounded by a layer termed an embryophore. A hexacanth surrounded by an embryophore is referred to as an oncosphere. An oncosphere in which the outer region of the embryophore is ciliated is referred to as a coracidium and is usually free-swimming.

In species that utilize vertebrate intermediate hosts, the oncosphere, after ingestion, penetrates the intestinal lining and enters a venule. It is carried by the circulating blood to several areas of the body where it develops into a cysticercus with an acetabulate scolex invaginated into a fluid-filled vesicle or bladder; hence, the common ...

The eggs hatch, each releasing a six-hooked larva, the oncosphere (also called the hexacanth), which penetrates the gut wall and reaches the muscles via the circulation. There the oncosphere fills with fluid and develops into the 8-mm cysticercus.

Embryogenesis within egg to form larva termed an oncosphere (6 or 10 hooked larva) Basic aquatic life-cycle adults in gut eggs (usually unembryonated) into environment; mature; hatch (many eggs operculated) coracidium (ciliated membranes around oncosphere) emerges usually eaten by first intermediate host (i.e. crustacean)

After ingestion of the eggs by the intermediate hosts, the larva (oncosphere) hatches from the egg, penetrates the intestinal mucosa, reaches the bloodstream, and migrates to the liver, lungs, and other internal organs.

A consensus was reached for standardised definitions of the oncosphere, hexacanth, coracidium, embryonic envelopes, outer envelope, inner envelope, embryophore, vitelline capsule, shell, and outer coat.

The predicted HSP20 homologue (onco2) also showed the highest expression at the stages of non-activated oncosphere (RPKM = 6, 545.23) and also showed expression at the activated oncosphere stage and in early stage metacestodes as well .

The meaning of ONCOSPHERE is a tapeworm embryo that has six hooks and is the earliest differentiated stage of a cyclophyllidean tapeworm —called also hexacanth embryo.