Variations in local adaptation of allopatric Fasciola hepatica to French Galba truncatula in relation to parasite origin

Abstract

Two French populations of Galba truncatula were subjected to experimental infections with Egyptian and French isolates of Fasciola sp. miracidia, originating from cattle and sheep, to compare characteristics of snail infections in allopatric and sympatric groups. All sampled Egyptian isolates were identified as Fasciola hepatica using microsatellite markers. Compared to snails infected with French miracidia, snail survival at day 30 post-exposure was significantly greater in the Egyptian groups, while prevalence of infection was significantly lower (in an Egyptian group infected with cattle-derived miracidia) or did not show any significant differences in the other three cases. The total number of metacercariae was significantly higher in the four Egyptian groups. However, snail population and the mammalian origin of F. hepatica had also a significant effect on this parameter. The dissection of snail cadavers showed a significantly higher number of free rediae in the Egyptian groups, even if snail population also had a significant effect on the redial burden. Both Egyptian isolates of F. hepatica could easily develop in French snails, causing a low mortality in snails and inducing a metacercarial production higher than that noted in sympatric infections. However, the mammalian origin of F. hepatica eggs and the quality of snail populations as intermediate hosts had to be taken into account for studying local adaptation in reason of their effects on this process.

Variations in cercarial production and the level of in vitro activation of metacercariae of two different isolates of Fasciola hepatica

“…In conclusion, analysis of the biological characteristics of F. hepatica isolates is complicated by the parasites inherent variability, the inherent susceptibility of snail strains to infection, allopatric and sympatric factors, and the influence of the mammalian host (Rondelaud and Dreyfuss 1995;Mas Coma et al 2001;Vignoles et al 2001;Walker et al 2006;Coelho et al 2009;Dar et al 2013). The differences observed between the F. hepatica isolates in this study highlight the need for further research into the parasites reproductive potential in the intermediate host, which will help to further our understanding of this parasite.…”

“…This snail strain appears susceptible to infection by the two F. hepatica isolates examined in this study, as evidenced by the high prevalence of infection, low pathogenicity and long survival among infected snails, and a high proportion of shedding snails. F. hepatica cercarial production can differ due to allopatric and sympatric host-parasite combinations, with allopatric combinations often exhibiting greater reproductive fitness (Gasnier et al 2000;Goumghar et al 2001;Coelho et al 2009;Sanabria et al 2012Sanabria et al , 2013Dar et al 2013). The CVL Weybridge strain has been passaged through the laboratory snail strain for several generations, consequently some degree of adaptation between the parasite and intermediate host is likely to be evident.…”

“…It has been reported that parasite strains can differ in certain phenotypic characteristics, including some aspects of reproductive potential (Walker et al 2006;McConville et al 2009), while the geographical relationship between the para- Kamil Januszkiewicz et al 510 site and the intermediate host can also be important (Gasnier et al 2000;Dar et al 2013;Sanabria et al 2013). The definitive host species, and the level of adaption between the host and parasite, also influences a range of liver fluke characteristics, both during contemporary and later developmental life stages, including fluke growth, metacercariae infectivity, egg numbers and developmental mortality (discussed in Norbury et al 2012).…”

A multiplex PCR for the detection of Fasciola hepatica in the intermediate snail host Galba cubensis

“…The transmission of the disease is dependent on the lymnaeid hosts that occur in a particular geographical area and their roles regarding transmission is influenced by the local adaptation of the species (Dar et al, 2013;Vázquez et al, 2014). In the Caribbean area, the lymnaeid snail Galba cubensis (formerly known as Lymnaea (Fossaria) cubensis) is considered the main intermediate host of F. hepatica (Gutiérrez et al, 2011).…”

Dinámica de la infestación por Fasciola hepatica en el sur de la provincia de Entre Ríos

“…Es entonces necesario, en algunos casos, el empleo de marcadores de mayor polimorfismo. En este sentido, una opción son los marcadores microsatélites o secuencias repetidas en tándem (SRT) (Hurtrez-Boussès et al, 2004;Dar et al, 2011Dar et al, , 2013Vilas et al, 2012;Cwiklinsky et al, 2015,). Los SRT son secuencias cortas repetidas de bases, situadas al azar en el genoma eucariota (Toth et al, 2000).…”