The populations of Galba truncatula, known for their natural infections with Haplometra cylindracea (Digenea, Plagiorchioidea), are better intermediate hosts for metacercarial production of Fasciola hepatica

Abstract

Laboratory investigations on Galba truncatula were carried out to determine if snails coming from four populations known to be natural intermediate hosts of Haplometra cylindracea, a digenean species of frogs, would not be better hosts for experimental infections with Fasciola hepatica than those originating from two communities in which H. cylindracea was never found in the past years. Uninfected G. truncatula were used to constitute six groups of snails (one per population) before being subjected to individual monomiracidial exposures with F. hepatica. Insignificant differences between mean values were noted for snail survival at day 30 post-exposure, prevalence of snail infection with F. hepatica, and prepatent period. In contrast, the duration of cercarial shedding and the number of F. hepatica cercariae in the four groups known for natural infections with H. cylindracea were significantly greater. The use of these last lymnaeid populations for experimental infections with F. hepatica allows to have high numbers of cercariae because of long patent periods and, as a consequence, strongly reduces the cost price of these larvae for scientific purposes and/or commercial production.

Symptoms of behavioural anapyrexia – Reverse fever as a defence response of snails to fluke invasion

“…The second option (ii) is supported by the fact that, after a decrease in the summer, in a shore-zone -the warmest place of the lake -the number of snails shedding cercariae usually increases suddenly in September. Taking into account the length of the development period of parasites from the miracidium to cercariae (Mouahid and Combes, 1997;Ataev et al, 1998;Drefyuss et al, 1999;Vignoles et al, 2007) this autumnal increase in fluke prevalence could not be caused by new infections in snails. A similar pattern of patent infections in L. stagnalis was discovered by _ Zbikowska (2006), and in over a dozen species of freshwater pulmonate and prosobranch snails by Cichy (unpubl.)…”

Natural light influences cercarial emergence of Calicophoron daubneyi but not that of Haplometra cylindracea from temperature-challenged Galba truncatula

“…The life cycle of the first parasite, C. daubneyi, was close to that of F. hepatica because both species often infected the same cattle and the same local snail host (G. truncatula) in central France (Szmidt-Adjidé et al 2000;Mage et al 2002). The second parasite, Haplometra cylindracea, had a different definitive host (frogs) but also used G. truncatula for development of its larval forms (Moukrim et al 1993;Goumghar et al 2000;Vignoles et al 2007Vignoles et al , 2011. Experimental infections of G. truncatula with C. daubneyi and natural infections of the same lymnaeid with H. cylindracea were thus followed under laboratory conditions to subject snails every week outdoors to a thermal shock under natural light during the patent period.…”

Natural infection ofFasciola hepatica(Trematoda: Fasciolidae) inBulinus truncatus(Gastropoda: Planorbidae) in northern Tunisia

“…The second hypothesis might be an effect of facilitation in snails simultaneously co-infected by two digeneans, the first species penetrating the mollusc and favouring the development of the second parasite (Augot et al , 1996). The last assumption may be the consequence of a particular aptitude that this bulinid population would have by sustaining frequent natural infections with another digenean (probably a species with two sporocyst stages in its life cycle), as demonstrated by Vignoles et al (2007). According to these authors, populations of G. truncatula , known for their natural infections with a plagiorchiid, are better intermediate hosts for metacercarial production of F. hepatica .…”