The development of rediae of Fasciola hepatica in Radix natalensis subjected twice to bimiracidial exposures.
Experimental infections of Egyptian Radix natalensis with a French isolate of Fasciola hepatica (each snail was subjected twice to a bimiracidial exposure) were carried out to determine how many sporocysts grew in these snails and to study the developmental patterns of redial generations. Single-sporocyst infections were found in 69.3% (34/49) of infected snails, with equivalent numbers of normal and abnormal patterns. Snails with two- and three-sporocyst infections were 24.4% and 6.1%, respectively. In single- and two-sporocyst infections at days 42 and 56 post-exposure, the total redial burden was significantly higher in snails with a normal redial development. In two- and three-sporocyst infections, the overall maturity of rediae was delayed at days 42 and 56. The high frequency of abnormal patterns in R. natalensis (53.1% of all infected snails showed degeneration of a first mother redia) might be due to incomplete adaptation between the snail population and the parasite. The delayed redial maturity in two- and three-sporocyst infections can mainly be explained by the volume of the snail body, which would be insufficient to allow the simultaneous differentiation of most rediae over time.
Dar
Y
Y
Department of Zoology, Faculty of Science, University of Tanta, Tanta, Egypt.
Vignoles
P
P
UPRES EA no. 3174, Faculties of Medicine and Pharmacy, 87025 Limoges, France.
Dreyfuss
G
G
UPRES EA no. 3174, Faculties of Medicine and Pharmacy, 87025 Limoges, France.
Rondelaud
D
D
UPRES EA no. 3174, Faculties of Medicine and Pharmacy, 87025 Limoges, France.
D027901:Acanthaceae / Q000469:parasitology*; D000818:Animals; D005210:Fasciola hepatica / Q000254:growth & development*; D033661:Oocysts / Q000254:growth & development; D059208:Parasite Load