Median-Joining network showing the relationships among <i>Furnestinia echeneis</i> haplotypes defined by COI sequences variation.

<p>Numbers along each branch designate the number of base differences among haplotypes. Circle sizes are proportional to the frequency of each haplotype. mv1–mv2 are median vectors and represent the possible extent of unsampled sequences or extinct ancestral sequences. In black, grey, white-grey and white background, <i>F. echeneis</i> haplotypes sampled from Adriatic wild sea bream, Adriatic cage sea bream adults, Adriatic cage sea bream fingerlings and western Mediterranean wild sea bream (Gulf of Lion), respectively.</p

Morphological Plasticity and Phylogeny in a Monogenean Parasite Transferring between Wild and Reared Fish Populations

<div><p>It is widely accepted that disease interactions between cultured and wild fish occur repeatedly, although reported cases have mainly relied just on the observation of similar symptoms in affected populations. Whether there is an explicit pathogen transfer between fish stocks, or each develops its own pathogen population, has been insufficiently studied and rarely supported by molecular tools. In this study, we used population dynamics and genetic structure of the monogenean <i>Furnestinia echeneis</i> in reared and neighbouring wild sea bream to indicate pathogen transfer, characterized by the phenotypic plasticity of the parasite attachment apparatus and the lack of phylogenetic differentiation. The observed pattern of genetic variation inferred by nuclear DNA Internal Transcribed Spacer 1 (ITS1) and mtDNA cytochrome C oxidase 1 (COI), between parasite populations is most likely caused by a recent shared demographic history like a reduced species area in the last glacial period. In spite of such recent expansion that populations underwent, <i>F. echeneis</i> shows differentiation in haptor morphometry as an adaptive trait in closely related populations at the aquaculture site. This suggests that differentiation in morphology may occur relatively rapidly in this species and that adaptive forces, not the speciation process, drives this monogenean parasitation. On the other hand, the observed phylogenetic inertia suggests a low to moderate gene flow (based on F<i>_ST</i>) between parasites in cultured and wild fish, evidencing for the first time the transfer of pathogens at the aquaculture site inferred by a molecular tool.</p></div

Estimates of pairwise genetic differentiation (<i>F</i>_ST) and gene flow (<i>Nm</i>) among populations of <i>Furnestinia echeneis</i> based on mitochondrial COI (lower diagonal) and ITS1 (upper diagonal, in italic) sequences data.

<p>In parentheses: Nm values; significance was tested with 10000 permutations, with significantly different populations indicated with an asterisk.</p

Characteristics of the three groups considered in the study.

<p>Group A: islands population; Group B: coastal urban population; Group C: inland rural population.</p

Principal component diagram (Factor 1 and Factor 2) of all morphometric variables measured on <i>Furnestinia echeneis</i> parasites from <i>Sparus aurata</i> from the Adriatic Sea.

<p>Solid circles indicate the tree different morphotype groups observed. Each parasite is identified by a letter and number corresponding to the host origin (a); Correlation diagram displaying variables in the two-factor space (PC1 vs. PC2) (b); dendrogram reconstructed using UPGMA on the Euclidian distances computed from standardised morphometric variables between parasite individuals from <i>S. aurata</i> with outlined morphotype groups (c); ordination diagram showing results of the discriminant analysis in the space defined by first two discriminant functions (canonical variables). Three main morphotype groups are clearly separated (d)., cage Adriatic population; •, wild Adriatic population; MT1, morphotype 1; MT2, morphotype 2; MT3, morphotype 3.</p

Anti-<i>Ascaris/Toxocara</i> IgG response.

<p>Anti-<i>Ascaris</i> spp. IgG (A) and anti-<i>Toxocara</i> spp. (B) NTU values in the population of <i>Anisakis</i> positive sera (green circles, n = 10 individual sera), and the population of <i>Anisakis</i> negative sera comprising: i) islands (red circles; n = 10 pooled sera) and coastal urban populations (blue circles; n = 10 pooled sera), and ii) inland rural population (black circles; n = 10 pooled sera). IgG levels are expressed as OD at 450 nm in NTU. Horizontal bars represent cut-off values for each parasite (positive <i>Ascaris</i> spp. >11; <i>Toxocara</i> spp. >11).</p

Concatenated phylogenetic tree (COI and ITS1) inferred by maximum likelihood (ML) analysis of <i>Furnestinia echeneis</i>.

<p>C - cage, Cf - cage fingerlings; W - wild; FW - France wild; OG1 - outgroup 1 <i>Lamellodiscus ignoratus</i> (JF427655); OG2 - outgroup 2 <i>L. ergensi</i> (JF427653.1) numbers at the end of sequence codes stand for fish numbers; small alphabetic letters (<i>a</i>, <i>b</i>, <i>c</i>, <i>d</i>) stand for monogenean individuals isolated from the same fish.</p

Odds ratio of the risk factors associated to seropositivity to <i>Anisakis</i> spp.

<p>Odds ratio of the risk factors associated to seropositivity to <i>Anisakis</i> spp.</p

Characteristics and personal habits of <i>Anisakis</i> spp. seropositive subjects.

<p>A: islands population; B: coastal urban population; F: female; M: male. The values in Ani s 1 and Ani s 7 columns show ODs obtained in ELISA for each serum (positives in bold). Cut-off values were OD = 0.09 for Ani s 1 and OD = 0.05 for Ani s 7.</p

Table_4_Rat and fish peripheral blood leukocytes respond distinctively to Anisakis pegreffii (Nematoda, Anisakidae) crude extract.xlsx

Infective third-stage larvae (L3) of the marine nematode Anisakis pegreffii cause inflammation and clinical symptoms in humans, their accidental host, that subside and self-resolve in a couple of weeks after L3 die. To characterise the differences in an early immune response of a marine vs. terrestrial host, we stimulated peripheral blood leukocytes (PBLs) of fish (paratenic host) and rat (accidental, human-model host) with A. pegreffii crude extract and analysed PBL transcriptomes 1 and 12 h post-stimulation. Fish and rat PBLs differentially expressed 712 and 493 transcripts, respectively, between 1 and 12 h post-stimulation (false discovery rate, FDR 2). While there was a difference in the highest upregulated transcripts between two time-points, the same Gene Ontologies, biological processes (intracellular signal transduction, DNA-dependent transcription, and DNA-regulated regulation of transcription), and molecular functions (ATP and metal ion binding) were enriched in the two hosts, showing an incrementing dynamic between 1 and 12 h. This suggests that the two distinct hosts employ qualitatively different transcript cascades only to achieve the same effect, at least during an early innate immunity response. Activation of later immunity elements and/or a combination of other host’s intrinsic conditions may contribute to the death of L3 in the terrestrial host.</p