Original Paper

Parasitology Research

, Volume 98, Issue 5, pp 462-467

First online:

Cercarial production of Fascioloides magna in the snail Galba truncatula (Gastropoda: Lymnaeidae)

  • P. VignolesAffiliated withFaculty of Pharmacy and Faculty of Medicine, UPRES EA 3174/USC INRA
  • , A. NovobilskýAffiliated withUniversity of Veterinary and Pharmaceutical Sciences
  • , D. RondelaudAffiliated withFaculty of Pharmacy and Faculty of Medicine, UPRES EA 3174/USC INRA Email author 
  • , V. BelletAffiliated withFaculty of Pharmacy and Faculty of Medicine, UPRES EA 3174/USC INRA
  • , P. TreuilAffiliated withFaculty of Pharmacy and Faculty of Medicine, UPRES EA 3174/USC INRA
  • , B. KoudelaAffiliated withUniversity of Veterinary and Pharmaceutical SciencesInstitute of Parasitology, Academy of Sciences of the Czech Republic
  • , G. DreyfussAffiliated withFaculty of Pharmacy and Faculty of Medicine, UPRES EA 3174/USC INRA

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Abstract

Single-miracidium infections of Fascioloides magna in two populations of Galba truncatula were carried out under laboratory conditions to count free rediae and cercariae in snail cadavers just after death. Cercaria-shedding snails were in low numbers, and their shell height at day 60 p.e. was significantly greater than that of numerous infected snails that died without cercarial shedding. In snails that died between days 44 and 60 p.e. (at 20°C), the numbers of second-generation rediae significantly increased with increasing shell heights of infected snails. First-generation rediae showed insignificant, quantitative variations, while scarce rediae of the third generation were only found in the highest snails. Cercariae were only produced by the second redial generation. In both groups of snails, free cercariae appeared from 6 mm of shell height, and their numbers increased in the upper classes up to 32.9 per snail. Metacercariae were only found from 9 mm of shell height and were in low numbers. The global cercarial production ranged from 163.5 to 210.0 in the highest classes of snail size from both groups and was limited, whereas the mean burdens of free rediae fluctuated from 39.5 to 43.9. The death of numerous infected snails without cercarial shedding might be explained by the presence of a very high number of second-generation rediae simultaneously growing within the body of these snails.