redia

The presence of partenites (rediae) and larvae (cercariae) in the body of mollusks was determined using a microscope "XS-6320 (MICROmed, Poltava, Ukraine)".

Drawings of life-cycle stages associated with the parasite's intermediate hosts (sporocysts and rediae, cercariae and metacercariae) are made on the surface of a water-filled tank.

In general, the development of trematodes (sporocyst or rediae) in the first intermediate host is known to have negative effects, such as the inhibition of functions in the parasitized tissues (Corte 2015), but with very limited host reaction, if any (Lauckner 1983, Galaktionov & Dobrovolskij 2003, Boehs et al.

The mechanisms involved in mixed infections can be of direct antagonism (Joe et al., 1968; Joe, 1973) by predation by the rediae of larvae of other trematodes (sporocysts, rediae and cercariae) or indirect antagonism through competition for food or space, by immunological mechanisms and toxic substances (Joe et al., 1965; Joe, 1966, 1973; Basch et al., 1969; Lim and Heyneman, 1972).

Cotylurus flabelliformis may also penetrate snails of Planorbidae and Physidae, but only if they are infected by other species of trematodes, where its encysts within sporocysts and/ or rediae (Cort, Olivier, & Brackett, 1941).

2) that penetrate the foot of an aquatic lymnaeid snail, developing into sporocysts that give rise to rediae by asexual reproduction.

Eggs then develop into germinal sacs (rediae) to produce the infective life stage (metacercaria).

Similar observations were recorded by [61] in the snail Archachatina marginata that the digestive gland tubule becomes compressed thereby resulting reduced tubular lumen of the gland as observed by that more cercaria and rediae were found in between the hepatic tubules and tunica propria causing extension of the space between tubules.

In fasciola more or less long finite cercarial production appears related to the number of generations of cercariogenous rediae and independent of the different lymnaeid vector species involved (Rondelaud and Barthe 1987; Rondelaud 1994; Rondelaud et al.

The success of infestation was determined by observation under light microscope or dissection of some snails to detect the presence of sporocysts or rediae in the snail's hepatopancreas.

We cracked the shells of each live red-rim melania snail between the first and second body whorl, removed the digestive tract, and examined each for rediae and cercaria of trematodes with a dissecting microscope at 100x total magnification.

Miracidia invade the soft tissues of snails (intermediate hosts), asexually form sporocysts, then rediae, and finally cercariae.