Table 1.
Summary data on snail species from echinostomatid infected freshwater sites in England.
Fig 1.
Photomicrographs of echinostomatid cercariae.
(A) Echinostoma revolutum (s.s.) stained with neutral red to show outlets of paraoesophageal gland cells (arrowhead) and one of seven tegumental finfolds (arrow), scale-bar: 200 μm. (B) Echinoparyphium recurvatum and (C) Echinoparyphium aconiatum stained with acetocarmine, scale-bars: 100 μm.
Fig 2.
Phylogenetic tree based on maximum likelihood analysis of partial nad1 sequences for identification of echinostomatid cercariae from lymnaeid snails.
Shaded clades indicate inclusion of species identified in this study. Species clades are collapsed. The scale-bar shows the number of nucleotide substitutions per site between DNA sequences. Nodal support values of ≥50 are shown.
Table 2.
Variables associated with Echinostoma revolutum (sensu lato) used to test compliance with the K/θ ratio for speciation.
Fig 3.
Divergence of populations of Echinostoma revolutum (s.s) across Eurasia.
(A) Haplotype network based on the most parsimonious geneology of nad1 sequences of E. revolutum (s.s.) from across Eurasia. Pie charts are scaled to represent the number of individual parasites sharing a particular nad1 haplotype (see scale for sizing); colours indicate geographical location (key); black circles represent hypothetical ancestral haplotypes. (B) Mantel test regression analysis showing a lack of significant correlation between genetic distance and geographical distance between E. revolutum (s.s.) isolates across Eurasia.
Table 3.
Neutrality and mismatch tests across major population groupings of Echinostoma revolutum (s.s.) from Eurasia.
Fig 4.
Mismatch distribution curves for nad1 haplotypes of Echinostoma revolutum (s.s.) isolates across Eurasia.
(A) Eurasia, combined data from Europe and Asia. (B) Isolates from Europe including those from England. (C) Asian isolates from Bangladesh and Thailand.
Fig 5.
Detection of selection and the impact of amino acid replacements on Echinostoma revolutum (s.s.) nad1.
(A) Contribution of synonymous and non-synonymous mutations to divergence (p-distance) between sequences within the Eurasian alignment based on pairwise differences between individual sequences within an alignment. (B) Provean analyses showing the distribution of amino acid replacements with all those with a score ≥-2.5 indicating a potential function altering change. (C) Protter 2D model of the nad1 protein illustrating the position and domains within which amnio acid replacements are occurring.