Issues Associated with Genetic Diversity Studies of the Liver Fluke, Fasciola Heptica (Platyhelminthes, Digenea, Fasciolidae)

Teofanova, Denitsa; Hristov, Peter; Yoveva, A.; Radoslavov, Georgi

doi:10.5772/34038

Cited by 4 publications

(3 citation statements)

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“…Both studies were based on sequencing several individual parasites but opened the path to population genetic approaches, a much needed follow-up of the helminth genomic era (Wit and Gilleard, 2017). Analysis of UK isolates based on neutral markers (microsatellites) confirmed substantial variation within F. hepatica populations (Beesley et al, 2017), which complements the population genetics studies of liver fluke populations carried out using ribosomal and mitochondrial markers to unravel geographical variations (reviewed by Teofanova et al, 2012). Although marked genetic heterogeneity between liver fluke populations is now well recognised, an association between F. hepatica haplotypes and specific phenotypic traits has yet to be made (reviewed in Zintl et al, 2015).…”

Section: Introductionmentioning

confidence: 94%

Low allelic diversity in vaccine candidates genes from different locations sustain hope for Fasciola hepatica immunization

Domínguez

González‐Miguel

Carmona

et al. 2018

Veterinary Parasitology

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Fasciola hepatica is a trematode parasite that causes fasciolosis in animals and humans. Fasciolosis is usually treated with triclabendazole, although drug-resistant parasites have been described in several geographical locations. An alternative to drug treatment would be the use of a vaccine, although vaccination studies that have been performed mainly in ruminants over the last 30 years, show high variability in the achieved protection and are not yet ready for commercialisation. Since F. hepatica exhibits a high degree of genomic polymorphism, variation in vaccine efficacy could be attributed, at least partially, to phenotypic differences in vaccine candidate sequences amongst parasites used in the challenge infections. To begin to address this issue, a collection of F. hepatica isolates from geographically dispersed regions, as well as parasites obtained from vaccination trials performed against a field isolate from Uruguay and the experimentally maintained South Gloucester isolate (Ridgeway Research, UK), were compiled to establish a F. hepatica Biobank. These collected isolates were used for the genetic analysis of several vaccine candidates that are important in host-parasite interactions and are the focus of the H2020 PARAGONE vaccine project (https://www.paragoneh2020.eu/), namely FhCL1, FhCL2, FhPrx, FhLAP and FhHDM. Our results show that F. hepatica exhibits a high level of conservation in the sequences encoding each of these proteins. The consequential low variability in these vaccine candidates amongst parasites from different geographical regions reinforces the idea that they would be suitable immunogens against liver fluke isolates worldwide.

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Section: Introductionmentioning

confidence: 94%

Low allelic diversity in vaccine candidates genes from different locations sustain hope for Fasciola hepatica immunization

Domínguez

González‐Miguel

Carmona

et al. 2018

Veterinary Parasitology

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“…When ISSR markers are compared to others of similar characteristics, such as RAPDs or SRAPs, some advantages are noticeable. Thus, RAPDs reproducibility is considered poor, and they need a significant laboratory work to standardize protocols in order to obtain reliable results (Teofanova et al 2012), while ISSRs are quite reproducible due to the use of longer primers allowing for higher annealing temperatures than those of RAPDs (Kojima et al 1998). On the other hand, SRAPs show less polymorphism than ISSRs due to the fact that SRAPs focus on genic regions.…”

Section: Discussionmentioning

confidence: 99%

Analysis of genetic variability of Fasciola hepatica populations from different geographical locations by ISSR-PCR

et al. 2014

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Inter-simple sequence repeats markers were used to determinate the genetic variability of Fasciola hepatica populations recovered from sheep and cattle from Spain (Sp1, Sp2, Sp3 and Sp4), UK (Eng), Ireland (Ir) and Mexico (Mex). Twenty five primers were tested but only five produced 39 reproducible bands, being 71.79% polymorphic bands. This percentage ranged from 10.26% in Sp4 to 48.72% in Sp1, and per host between 28.21 and 48.72% in sheep and between 10.26 and 38.46% in cattle. This relatively low range of genetic diversity within populations, with a mean of 34.40%, implies that a large proportion of variation resided among populations. The population differentiation (Gst = 0.547) indicated that 54.7% of variation is due to differences between populations and 45.3% due to differences within population. The Nei's distance ranged between 0.091 and 0.230 in sheep and between 0.150 and 0.337 in cattle. The genetic relationships between populations and individuals were shown by a UPGMA dendrogram and a principal coordinate analysis; both grouped all populations separately from Sp4, a population of from the Midwest of Spain with the lowest level of diversity. Small genetic distances were observed between Eng and Ir, on the one hand, and Sp1, Sp2, Sp3, from the Northwest of Spain, together with Mex, on the other.

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“…Studies of genetic diversity in the liver fluke have started to emerge, and are relevant in following the dispersal of the species and identifying and characterizing the emergence of variants with particular properties, such as drug resistance (reviewed in Ai et al , 2011; Teofanova et al , 2012). The genetic characterization of defined TCBZ-R populations of European and Australian origin based on mitochondrial markers ( nad -1 and cox -1) showed that these populations are genetically diverse, suggesting that no ‘bottleneck’ occurred due to selective pressure (Walker et al , 2007; Elliott et al , 2014).…”

Section: Control Approachesmentioning

confidence: 99%

Fasciolosis in South America: epidemiology and control challenges

Carmona

Tort

2016

J. Helminthol.

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Fasciolosis caused by Fasciola hepatica severely affects the efficiency of livestock production systems worldwide. In addition to the economic impact inflicted on livestock farmers, fasciolosis is an emergent zoonosis. This review emphasizes different aspects of the disease in South America. Available data on epidemiology in bovines and ovines in different countries, as well as a growing body of information on other domestic and wildlife definitive hosts, are summarized. The issue of drug resistance that compromises the long-term sustainability of current pharmacological strategies is examined from a regional perspective. Finally, efforts to develop a single-antigen recombinant vaccine in ruminants are reviewed, focusing on the cases of leucine aminopeptidase or thioredoxin glutathione reductase.

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Issues Associated with Genetic Diversity Studies of the Liver Fluke, Fasciola Heptica (Platyhelminthes, Digenea, Fasciolidae)

Cited by 4 publications

References 54 publications

Low allelic diversity in vaccine candidates genes from different locations sustain hope for Fasciola hepatica immunization

Low allelic diversity in vaccine candidates genes from different locations sustain hope for Fasciola hepatica immunization

Analysis of genetic variability of Fasciola hepatica populations from different geographical locations by ISSR-PCR

Fasciolosis in South America: epidemiology and control challenges

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