Cercarial productivity of redial generations in single-miracidium infections of Lymnaea truncatula with Paramphistomum daubneyi or Fasciola hepatica

2000 ◽  
Vol 74 (1) ◽  
pp. 1-5 ◽  
Author(s):  
M. Abrous ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Fasciola Hepatica ◽  
The Other ◽  
Redial Generation ◽  
Post Exposure ◽  
Laboratory Conditions ◽  
Lymnaea Truncatula

AbstractSingle-miracidium infections of Lymnaea truncatula with Paramphistomum daubneyi or with Fasciola hepatica were carried out under laboratory conditions to count free rediae, their germinal embryos, and to determine the cercarial productivity of each redial generation. In snails infected by P. daubneyi, the cercariae were produced by the first (8.7 cercariae per redia) and second (8.9 per redia) generations. At day 63 post-exposure, they corresponded, respectively, to 53.9% and 46.1% of cercariae produced by all rediae. In snails infected by F. hepatica, the majority of cercariae were produced by the R2a group (18.2 cercariae per redia) and corresponded to 66.0% of cercariae produced all rediae. The cercariae produced by the other redial groups were more limited in number: 17.5 per redia in the R1b group (28.7%) and 2.0 per redia in the R2b/R3a group (5.3%). Cercarial productivity of P. daubneyi until day 63 post-exposure was more limited in number than that of F. hepatica: a total of 145 cercariae per snail versus 427 per snail.

Fasciola gigantica: larval productivity of three different miracidial isolates in the snail Lymnaea truncatula

2003 ◽  
Vol 77 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Y. Dar ◽  
P. Vignoles ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Geographic Origin ◽  
Fasciola Gigantica ◽  
The Other ◽  
Redial Generation ◽  
Post Exposure ◽  
Experimental Infections ◽  
Other Hand ◽  
Lymnaea Truncatula ◽  
Egyptian Isolate

AbstractBimiracidial infections of Lymnaea truncatula with three isolates of Fasciola gigantica, originating from China, Egypt and Madagascar, were carried out to determine the effect of geographic origin of the parasite on the larval productivity of redial generations. The prevalences of experimental infections in snails exposed to strains from Madagascar, China and Egypt were 20.8%, 60.0% and 80.0%, respectively. At day 49 post-exposure (p.e.), the total number of free rediae in snails infected with the Egyptian isolate was significantly higher than that recorded in the Madagascan group. On the other hand, at day 49 p.e., the majority of cercariae in the Chinese and Egyptian groups were produced by R2a rediae (70.6% and 66.6% of cercariae produced by all live rediae), while, in the Madagascan group, the cercariae were produced mainly by the first redial generation. Snails infected with the Egyptian isolate of miracidia developed more live rediae and, consequently, could produce a higher number of cercariae. As a result, L. truncatula snails were highly adapted to infections with the Egyptian and Chinese isolates of F. gigantica.

Snail Hosts of Fasciola hepatica in Britain

1950 ◽  
Vol 24 (1-2) ◽  
pp. 63-74 ◽  
Author(s):  
S. Brian Kendall
Keyword(s):  
Experimental Evidence ◽  
Fasciola Hepatica ◽  
The Other ◽  
Laboratory Conditions ◽  
Full Development

1. This paper presents experimental evidence to show that Limnaea truncatula is not the only British snail susceptible to infection with Fasciola hepatica.2. Of the six British species of Limnaea, five may be infected under laboratory conditions, L. auricularia proving resistant to infection. Full development of the parasite occurs in L. truncatula, L. slagnalis, L. palustris and L. glabra, while development as far as the production of rediae occurred on one occasion in L. pereger. Of the susceptible species L. truncatula may be infected at any age or size, but the other species are susceptible only during the first few days after hatching.3. F. hepatica appeared to be relatively pathogenic to hosts other than L. truncatula even though the level of infection (as evidenced by the number of rediae which developed) was considerably lower than in the more usual host.

Fasciola hepatica: the infection rate and the development of redial generations in Lymnaea truncatula exposed to miracidia after experimental desiccation and activation in water

1994 ◽  
Vol 68 (1) ◽  
pp. 63-66 ◽  
Author(s):  
D. Rondelaud
Keyword(s):  
Infection Rate ◽  
First Generation ◽  
Second Generation ◽  
Fasciola Hepatica ◽  
The Other ◽  
Lymnaea Truncatula

AbstractAdult Lymnaea truncatula were subjected to 10 days of experimental desiccation and then remained in water for 1 or 8 days before each was exposed to a single miracidium. The infection rate was lower in these snails than in infected controls that were not exposed to stress (52–54% vs 73%). The redial burden clearly decreased in stressed snails (18–25 rediae per snail) than in controls (43 rediae). This numerical decrease concerned essentially: i) live independent rediae of the first generation and the first cohort of the second generation, and ii) dependent rediae of subsequent generations. Mature rediae were more numerous in the first cohort of the second generation than in the other generations. Desiccation before exposure limited the size of the redial burden but placement in water for 8 days just after the stress attenuated the effects of this factor.

Redial growth and cercarial productivity of Fasciola hepatica in three species of young lymnaeid snails

2002 ◽  
Vol 76 (3) ◽  
pp. 269-272 ◽  
Author(s):  
P. Vignoles ◽  
G. Dreyfuss ◽  
D. Rondelaud
Keyword(s):  
Body Length ◽  
Significant Influence ◽  
Fasciola Hepatica ◽  
Snail Species ◽  
Post Exposure ◽  
Experimental Infections ◽  
Laboratory Conditions ◽  
The Mean ◽  
Cattle Strain

AbstractExperimental infections of 1-mm high snails using three populations of Lymnaea (L. glabra, L. ovata and L. truncatula) and a cattle strain of Fasciola hepatica miracidia were carried out under laboratory conditions to determine if the snail species had an effect on the number of free rediae, their growth, and cercarial productivity in relation to each redial category (R1a, R1b, R2a, or R2b/R3a). The total number of rediae ranged from 6.4 to 7.5 per snail. The mean body length of rediae varied from 1–1.2 mm (R1a) to 0.3–0.4 mm (R2b/R3a). The width of the intrapharyngeal lumen also varied from 26.0–38.8 μm to 3.0–4.2 μm, respectively. The redial category had a significant effect on both measurements, whereas snail species only had a significant influence on body length. The mean number of cercariae produced by all living rediae at day 49 post-exposure ranged from 63.0 in L. glabra to 87.2 in L. truncatula. In L. ovata and L. truncatula, 55.8% and 58.6% of cercariae, respectively, were produced by R2a rediae, whereas 53.9% of cercariae in L. glabra were formed by the R1b rediae. When young snails were infected with F. hepatica, the species of snail had an effect on the number of living rediae, their length and their cercarial productivity.

Larval development of Fasciola hepatica in experimental infections: variations with populations of Lymnaea truncatula

2002 ◽  
Vol 76 (2) ◽  
pp. 179-183 ◽  
Author(s):  
P. Vignoles ◽  
G. Dreyfuss ◽  
D. Rondelaud
Keyword(s):  
Retrospective Study ◽  
Genetic Variability ◽  
Larval Development ◽  
Experimental Infection ◽  
Fasciola Hepatica ◽  
The Other ◽  
Mammalian Host ◽  
Cercarial Production ◽  
Lymnaea Truncatula ◽  
Low Prevalence

AbstractA retrospective study was undertaken on 70 French populations of Lymnaea truncatula experimentally infected with Fasciola hepatica to determine whether or not susceptibility of snails to infection influenced redial and cercarial production. Results were compared with those obtained from two control populations, known for prevalences higher than 60% when experimentally infected with F. hepatica. In the 70 other populations examined, the prevalences ranged from 2 to 75%. In 55 of these populations, where the prevalence was more than 20%, a high proportion (50.1–56.8%) of snails died after cercarial shedding, whereas in the other groups (non-shedding snails with the most differentiated larvae being free cercariae, rediae containing cercariae, immature rediae, or sporocysts, respectively), snail death was significantly less. In 11 populations, where the prevalence values were 5–19%, only 14% of snails died after cercarial shedding, whereas snails with free cercariae, rediae with cercariae, or immature rediae showed significant increases in snail mortality. In the remaining four snail populations, with prevalences of less than 5%, the most differentiated larval forms were only immature rediae and/or sporocysts. Overall, the number of rediae containing cercariae significantly decreased with decreasing prevalence values. The low prevalence of experimental infection in several populations of snails might be explained by the occurrence of natural infections with miracidia originating from a mammalian host other than cattle, and/or by genetic variability in the susceptibility of snails to infection.

A field study of natural infections in three freshwater snails with Fasciola hepatica and/orParamphistomum daubneyiin central France

2000 ◽  
Vol 74 (3) ◽  
pp. 189-194 ◽  
Author(s):  
M. Abrous ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Field Study ◽  
Fasciola Hepatica ◽  
Acid Soil ◽  
Natural Infection ◽  
The Other ◽  
Freshwater Snails ◽  
Laboratory Conditions ◽  
Concurrent Infections ◽  
Investigation Period ◽  
June July

AbstractNatural infections of three freshwater snails withFasciola hepaticaand/orParamphistomum daubneyiwere studied during two periods in 1996 and 1997 (June–July and September–October) on 18 farms located in the departments of Vienne and Haute Vienne (central France), and known for low prevalences ofF. hepaticainfections in ruminants. A total of 1573Lymnaea glabraand 1421L. truncatula6 mm high or more were collected in the meadows of 13 farms and dissected under laboratory conditions. Snails with single or concurrent infections ofF. hepaticaand/orP. daubneyiwere found for eachLymnaeaspecies. InL. truncatula, global prevalences of natural infections withF. hepatica(3.8% in June–July, and 3.6% in September–October) were significantly greater than those recorded forP. daubneyi(1.1% and 0.8%, respectively). InL. glabra, global prevalences ofF. hepaticainfections (0.4% in each investigation period) were significantly lower than those found inL. truncatula, whereas there were no significant differences between prevalences ofP. daubneyiinfections. A total of 2721Planorbis leucostomameasuring at least 4 mm in diameter were collected in the meadows of the other five farms on whichL. truncatulawas absent. In these planorbids, global prevalences of natural infections withF. hepaticawere 0.4% in each period of investigation. Contrary to fasciolosis, snail infections withP. daubneyiwere not noted on all farms of the Vienne and Haute-Vienne departments. Natural single or concurrent infections withF. hepaticaand/orP. daubneyiinL. glabraand a natural infection ofP. leucostomawithF. hepaticawere found in swampy meadows on acid soil.

Characteristics of Fasciola hepatica infections in Galba truncatula originating from riverbank populations

2010 ◽  
Vol 85 (1) ◽  
pp. 28-32 ◽  
Author(s):  
P. Vignoles ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Fasciola Hepatica ◽  
Acid Soil ◽  
Spring Water ◽  
The Other ◽  
Breeding Method ◽  
Galba Truncatula ◽  
Post Exposure ◽  
Petri Dishes

AbstractFour geographical strains of Galba truncatula living on riverbanks (the first on a sedimentary soil and the other three on an acid soil) were subjected to bimiracidial exposures with Fasciola hepatica to study their aptitude for cercarial shedding and to count metacercariae in snails dissected at day 42 post-exposure. All snails were reared in 14-cm Petri dishes at 24°C, with the same spring water (60–73 mg/l of Ca2+) and the same diet (grass and lettuce leaves). Metacercariae of F. hepatica were noted in the four populations after a cercarial shedding or after snail dissection. However, in spite of the breeding method used, the characteristics of snail infections varied with the origin of each geographical strain. For example, the shell heights of infected snails at day 42 were close to those found for the corresponding adults in the field (6.8–8.0 mm for the population living on the sedimentary soil, but only 4.6–5.5 mm for another strain originating from the acid soil). This variability may be explained by assuming that the diet of these riverbank G. truncatula would be different from that of snails living in swampy meadows. However, another hypothesis based on the influence of snail habitat on the characteristics of snail life cannot be excluded.

The presence of predators modifies the larval development of Fasciola hepatica in surviving Lymnaea truncatula

2002 ◽  
Vol 76 (2) ◽  
pp. 175-178 ◽  
Author(s):  
D. Rondelaud ◽  
P. Vignoles ◽  
G. Dreyfuss
Keyword(s):  
Survival Rate ◽  
Larval Development ◽  
Significant Variation ◽  
Fasciola Hepatica ◽  
Stress Reaction ◽  
Experimental Exposure ◽  
Post Exposure ◽  
Progressive Development ◽  
Experimental Infections ◽  
Lymnaea Truncatula

AbstractExperimental infections of Lymnaea truncatula with Fasciola hepatica were performed to study the consequences of the presence of predators (sciomyzid larvae or zonitid snails) on the characteristics of larval F. hepatica development in surviving snails. Controls consisted of infected snails that were not subjected to predators. Compared to controls, the survival rate at day 30 post-exposure, the duration of cercarial shedding, and the number of cercariae shed by surviving snails were significantly lower when predators were present in snail breeding boxes, whatever the type of predator used. In contrast, the prevalences of Fasciola infections in snails, and the length of time between exposure and the onset of cercarial shedding showed no significant variation. The progressive development of a stress reaction in surviving snails against predators during the first 30 days of experimental exposure to F. hepatica would influence snail survival during the cercarial shedding period and, consequently, the number of cercariae shed by the snails.

Total cercarial output in two populations of Galba truncatula experimentally infected with Fasciola hepatica

2009 ◽  
Vol 84 (1) ◽  
pp. 77-80
Author(s):  
P. Vignoles ◽  
F. Aimeur ◽  
A. Titi ◽  
D. Rondelaud ◽  
A. Mekroud ◽  
...  
Keyword(s):  
Fasciola Hepatica ◽  
Snail Host ◽  
The Other ◽  
Galba Truncatula ◽  
Post Exposure ◽  
Complete Development ◽  
Experimental Infections ◽  
Two Populations

AbstractExperimental infections of pre-adult Galba truncatula (two populations) using one, two, three or five miracidia of Fasciola hepatica per snail were carried out to determine the total number of cercariae produced by snails when they were sacrificed at day 70 post-exposure (at 24°C). When the number of miracidia used for each snail increased at exposure, significant numerical augmentations of live rediae and of intraredial differentiating cercariae were noted. In contrast, only insignificant differences between mean numbers of free cercariae were found. The number of metacercariae produced by each snail (after shedding and/or after dissection) increased in infections with up to three miracidia per snail in each population and strongly decreased in infections with five miracidia per snail. Compared to the other types of infections, the delay of cercarial differentiation noted in the five-miracidia groups was probably due to the volume of the snail host, which would be too small to assure the complete development of five sporocysts.

Variability of Fasciola infections in Lymnaea truncatula as a function of snail generation and snail activity

1997 ◽  
Vol 71 (2) ◽  
pp. 161-166 ◽  
Author(s):  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Fasciola Hepatica ◽  
Prepatent Period ◽  
The Other ◽  
Infection Rates ◽  
Patent Period ◽  
Summer Generation ◽  
Experimental Infections ◽  
Field Investigations ◽  
Lymnaea Truncatula

AbstractField investigations were carried out over a 4-year period in three farms of the Haute-Vienne department (France) in order to determine the prevalence of Fasciola hepatica infection in the annual generations of Lymnaea truncatula. Infection rates found in March were significantly lower than those recorded in July or in September (0.8% to 2.2% compared to 5.7% to 13.5% and 4.4% to 9.3%, respectively). They were always lower in overwintering snails than in other snail generations (summer generation in 1989,1990 and 1991; spring and summer generations in 1992). Experimental infections of L. truncatula by F. hepatica were performed to evaluate the characteristics of Fasciola infection with reference to snail generation and snail activity. Survival of summer generation snails at day 30 postexposure was significantly lower in snails collected in September than in those collected in May and June. In the winter generation of L. truncatula, snail survival was significantly higher in snails collected from December to March than in those from November. The prevalence of infection was significantly lower in snails collected in September (summer generation) than in those collected from December to March (winter generation). The duration of the prepatent period was significantly delayed in snails collected from January to March (a mean of 54.2 to 58.2 days instead of 43.1 to 49 days in the other groups), whereas that of the patent period was significantly shorter (5 to 9.3 days instead of 18.3 to 40.3 days, respectively). In snails collected from January to March, the number of metacercariae was significantly lower than that found from other snail groups (a mean of 21.5 to 42 metacercariae instead of 72.8 to 151.4 cysts, respectively). Fasciola infections of L. truncatula originating from spring and summer generations were more efficient than those from the winter generation of snails.

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