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The redial and cercarial production of a Digenean in the snail host is lower when no cercarial shedding occurs

Authors :
Dreyfuss G.
Vignoles P.
Rondelaud D.
Source :
Parasite, Vol 16, Iss 4, Pp 309-313 (2009)
Publication Year :
2009
Publisher :
EDP Sciences, 2009.

Abstract

Single- and double-miracidium exposures of Galba truncatula with Fasciola hepatica (two groups) or with Paramphistomum daubneyi (two groups) were carried out under laboratory conditions to compare parasite production in cercaria-shedding snails (CS snails) with that found in snails without emission (NCS snails). Free rediae and cercariae were thus counted in snails from both categories after their dissection at regular intervals (at 24 °C). In the four groups, the numbers of free rediae and free cercariae found at day 75 post-exposure (F. hepatica) or at day 85 (P. daubneyi) were significantly greater in CS snails than in NCS ones. The number of cercariae in NCS subgroups did not show any significant variation from day 45 p.e. to day 75 (F. hepatica, the two groups) or from day 55 to day 85 (P. daubneyi, singlemiracidium infections), while it significantly decreased with increasing time of infection in the double-miracidium infections with P. daubneyi. In NCS snails, the presence of too numerous free cercariae within the snail’s body (the volume of the body allows development only of a given number of rediae) might rapidly block out redial development and intraredial differentiation of other cercariae. The numerical diminution of P. daubneyi cercariae in the NCS snails (double-miracidium group) might probably be due to the lysis of new cercariae just formed, probably in reason of a lack of nutrients available for these larvae within the snail.

Details

Language :
English
ISSN :
1252607X and 17761042
Volume :
16
Issue :
4
Database :
Directory of Open Access Journals
Journal :
Parasite
Publication Type :
Academic Journal
Accession number :
edsdoj.0429361c66f4074b8da687da023e48f
Document Type :
article
Full Text :
https://doi.org/10.1051/parasite/2009164309