Definition

Noun: 1. A larval stage of a parasitic flatworm (trematode or fluke): A cercaria is a free-swimming, tadpole-shaped larva that develops within an intermediate host (usually a snail) and emerges to seek the next host in the parasite's life cycle. Its most distinctive feature is a long, muscular tail used for locomotion, which is lost when it matures into the next stage.

Examples of Usage

• The cercaria emerges from the snail and swims in the water, searching for a suitable vertebrate host.
• Under the microscope, you can clearly see the forked tail of the cercaria.
• The life cycle of the liver fluke includes a cercaria stage that encysts on aquatic plants.

Advanced Usage

• Cercarial dermatitis: Also known as "swimmer's itch," this is a skin rash caused when cercariae of certain non-human schistosomes penetrate human skin by mistake. They die in the skin, causing an allergic reaction.
  • Swimming in the lake gave him a case of cercarial dermatitis.

Variants and Related Words

• Cercarial (adjective): Of or relating to a cercaria.
  • The cercarial stage is critical for transmission.
• Cercariae (plural): The standard plural form of cercaria.
  • Thousands of cercariae were released from the infected snail.

Synonyms

• Larva (specifically, a trematode larva)
• Trematode larva

Related Terms (Context-Specific)

• Miracidium: The earlier, ciliated larval stage that infects the first intermediate host (usually a snail).
• Metacercaria: The encysted, resting larval stage that follows the cercaria and is infective to the final host.
• Sporocyst / Redia: Developmental stages within the snail host that produce the cercariae.

Noun

1. tadpole-shaped parasitic larva of a trematode worm; tail disappears in adult stage