Five hours post-exposure (PE) the fish were dissected, showing many free young metacercariae, not yet encysted in the body musculature.
In one snail, metacercariae of normal Tetracotyle form were observed encysted in their own sporocysts; cysts of 180-210 (195 [+ or -] 12) long and 135-165 (139 [+ or -] 10) wide, with thick double wall.
glabrata), which is similar to Furcocercaria V in the presence of colourless eye-spots, sensory hairs in the tail stem, resting position in water, and in having a metacercariae of normal Tetracotyle form encysted in some host analized.
Other trematodes collected were Philophthalmus gralli, an eye fluke found in waterfowl, and Haplorchis, a trematode that encysts
in muscle of fish at the maxillary, operculum, and insertions of fins.
They burrowed the intestinal wall and encyst
in flesh and liver tissues of the host fish.
labiatopapillosa (a North American species) encysted
in the stomach wall, mesentery and muscles of frogs.
Unfortunately, it is not clear whether the hairworm larvae were developing or just encysted
in these hosts.
After several developmental stages (sporozoites, redia, and cercariae) free-swimming cercariae leave the intermediate hosts, swim actively through water, and adhere to plants, where they encyst to form metacercariae (the infectious stage).
Encysted cercariae (metacercariae) may remain viable for many months unless they become desiccated.
The cercariae are released from the snails and encyst (become metacercariae) on various water plants such as water caltrop, water chestnut, lotus (on the roots), and water bamboo.
In the amphipod Gammarus insensibilis, infective larvae (i.e., cercariae) of Microphallus papillorobustus (Trematoda, Microphallidae) systematically migrate into the amphipod's brain, encyst
in the cerebroid ganglia (Rebecq 1964) and consequently strongly alter their host behavior by inducing a positive phototactism, a negative geotactism and an aberrant-suicidal evasive behavior (Helluy 1983a,b).