Snail diversity in small water bodies and its
potential implication on the epidemiology of
fasciolosis in Belgium
Y. CARON , S. LASRI , V. GILLARDIN , T. DE BIE , D. ERCKEN , B. LOSSON ULG-FMV, Liège FUNDP, Namur KUL, Leuven KBIN, Bruxelles 1 1 2 3 4 1 1 2 3 4
Problematic
?
Ponds and biodiversity Risk of parasitic infections
Fasciolosis
Family: FasciolidaeAetiological agents: F. hepatica; F. gigantica Complex life cycle: Intermediate hosts
Fasciola hepatica Life Cycle Egg in feces Miracidia Intermediate Host : - Galba truncatula Cercaria Definitives hosts : - Sheep - Cow - Man - Rabbit ... Metacercaria
Fasciola hepatica Life Cycle Definitives Hosts : - Sheep - Cow - Man - Rabbit ... Metacercariae
Adult liver fluke in biliary duct with cholangitis Cholangitis
Fasciola hepatica Life Cycle Miracidia Eggs in feces Definitives hosts : - Sheep - Cow - Man - Rabbit ... Intermediate Host : - Galba truncatula Cercaria Metacercaria
Fasciola hepatica Life Cycle
Eggs in feces
Fasciola hepatica Life Cycle Intermediate Host : - Galba truncatula Cercaria Metacercaria Definitives hosts : - Sheep - Cow - Man - Rabbit ... Eggs in feces Miracidia
Fasciola hepatica Life Cycle
Intermediate host :
Another snails species which may be involved Lymnaeidea : - Radix peregra - Radix ovata - Lymnaea stagnalis - Stagnicola palustris - Pseudosuccinea columella - Radix auricularia ? Physidae : - Physella acuta
Serological prevalences of bovine fasciolosis within the provinces in 1997
Aims of the study
Biodiversity of snail species in small water bodies Assessment of trematode parasite (F. hepatica) infection
Sampling campains
1st : Summer 2003 (July to September) 2nd : Spring 2004 (April to June)
- Pools are classified as : Intensive
Extensive Natural
- Pools are classified as : Intensive
Extensive Natural
- Pools are classified as : Intensive
Extensive Natural
1st campain (July to September 2003)
Methods
Collection of snails
Identification (Rondelaud, 1998)
Snail species
L. stagnalis
47% (9/19)
Snail species
R. ovata
37% (7/19)
Snail species
R. peregra
26% (5/19)
Snail species
Physella acuta
11% (2/19)
Snail species
G. truncatula
0% (0/19) ?????
DNA analysis
Extraction of DNA Phenol / chloroform PCR technique
using specific primers of F. hepatica Southern blot technique
PCR results
T: positif control; A and B: R. peregra; C: L. stagnalis; D: R. ovata; E: negatif control; F: negatif sample
Southern blot results
F. hepatica in 4 pools : 2 extensives 1 intensive 1 natural F. hepatica in 3 species : R. peregra L. stagnalis R. ovata
Distribution for the 4 species collected during the first campain and localisation of the positives samples ( R. peregra; R. ovata;
Fasciola hepatica serological prevalences within the provinces
2
ndcompain (April to June 2004)
Snail species
5 species have been identified
R. ovata L. stagnalis R. peregra R. auricularia
Snail species
R. ovata
Snail species
L. stagnalis
34,5% (19/55)
Snail species
R. peregra
34,5% (19/55)
Snail species
R. auricularia
Snail species
G. truncatula
5,5% (3/55)
DNA analysis
F. hepatica in 8 pools : 4 intensives
3 extensives (of which 2 were positive in the 1st campaign)
1 natural F. hepatica in 3 species : R. peregra L. stagnalis R. ovata Fasciola sp in 1 species ? R. auricularia
Distribution for the 5 species collected during the second campain and localisation of the positives samples
Fasciola hepatica serological prevalences within the provinces
Discussion
Absence of G. truncatula:
- Climatic conditions in summer 2003
Infected natural pool:
- Presence of wildlife or rodent as final host of F.
hepatica
Other infected snail species: - Vectors of F. hepatica ? - Biotope of G. truncatula
- Competition between species
Influence of the intermediate host species in
the development of F. hepatica
Preliminary results: - R. peregra is positive by PCR - R. peregra produces Metacercaria In prospect :
- Pathogenicity for rats ?
- Experimental infections of L. stagnalis and R.
