Haplometra cylindracea(Zeder, 1800) (Trematoda: Plagiorchiidae): variation in the dates of cercarial shedding for overwinteringGalba truncatula

Abstract

Natural infections of Galba truncatula with Haplometra cylindracea were followed from 2001 to 2009 to determine if their characteristics were similar when snails came from water collections frequented by Bufo bufo or by frogs and newts for their egg-laying. Snail samples were collected from both types of sites to count shed cercariae for three days and also free cercariae when snails were dissected. In sites only frequented by B. bufo, cercarial shedding occurred earlier than in those colonized by frogs and newts (March instead of April-May). In contrast, the number of cercariae shed during three successive days was significantly higher in May. This variation in the dates of cercarial shedding might be due, either to a synchronism between cercaria-releasing snails and the presence of the definitive host (tadpoles) in water collections, or to an earlier infection of overwintering snails in autumn by H. cylindracea miracidia in the case of toad-frequented sites.

Larval trematode infections in Galba truncatula (Gastropoda, Lymnaeidae) from the Brenne Regional Natural Park, central France

“…In Brenne, the presence of H. cylindracea was noted in snails living in pools and was never found in snail populations colonizing road ditches. In contrast, this parasite was often found in snails living in road ditches on acidic soils (Goumghar et al , 2000; Vignoles et al , 2011a). This difference may be explained mainly by the higher richness of water bodies in Brenne, so that frogs (the definitive host of this parasite) preferentially selected pools, more permanent than water present in road ditches, for their reproduction and did not use ponds because of predators which are more numerous in this type of habitat.…”

“…Larval forms of C. daubneyi , F. hepatica and H. cylindracea were directly identified because of our 30-year experience acquired with experimental and/or natural infections of G. truncatula with digenean species (Vignoles et al , 2011a, b; Sanabria et al , 2012; Dar et al , 2013). When larval forms of another trematode were detected, neutral red and/or Nile blue were used to study their morphology.…”

Larval trematode infections inLymnaea glabrapopulations living in the Brenne Regional Natural Park, central France

“…This difference might be due to the fact that infected frogs (the definitive host of this digenean) would infect numerous snails during their stay in pools. The finding of numerous H. cylindracea -infected G. truncatula in the populations studied by Vignoles et al [ 29 ] between 2001 and 2009 on acid soils supports this last hypothesis. In the present study, larval forms of four other digenean species were also found in the body of L. glabra ( Table 2 ).…”

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

“…The wild population of G. truncatula was living in a ditch along a dirt track (46°52′ 51″ N, 1°5′ 50″ E) located on the commune of Veyrac, department of Haute Vienne (central France). This site was regularly investigated by our team from 2001, and natural infections of snails with H. cylindracea were regularly noted over time with prevalence values ranging from 28.5 to 68.0 % (Vignoles et al 2011). As the size of this population was lower than that used for C. daubneyi infections, only 200 adult snails, measuring 6±0.2 mm in height and belonging to the overwintering generation, were collected from this habitat at the end of February 2014.…”

“…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.…”