New Insights Into the Genetic Variability of Fasciola Hepatica (Trematoda) in Algeria and Relationships with Other Geographic Regions Revealed By Mitochondrial DNA.

This study aims to investigate the level of genetic variability of Fasciola hepatica flukes isolated from cattle in Algeria and to determine the phylogenetic and phylogeographic relationships with sequences isolated worldwide. Mitochondrial (Cytochrome c Oxidase subunit I gene - COI) and nuclear markers (Internal Transcribed Spacers of nuclear ribosomal DNA - ITS) for 24 F. hepatica flukes isolated from 12 cattle in North Algeria were characterised. Only two haplotypes were obtained for the COI gene, resulting in a low level of genetic variation. The analysis of variation among the COI sequences isolated from around the world did not show high levels of genetic divergence, and the phylogenetic analysis revealed a genetic similarity among F. hepatica isolates from different areas of the world. The analysis of the ITS region showed a low level of variability, which prevented obtaining informative phylogenetic and phylogeographic results. The present study also revealed that specimens of F. hepatica are genetically similar in different hosts, indicating that the genetic structure among populations of this parasite is not influenced by the host species. The low levels of genetic variation for COI and ITS regions among fluke isolates from all continents are consistent with a common origin for the flukes' worldwide distribution.

Morphological and genetic variability of the cryptic Gyrodactylus sphinx and Gyrodactylus gerasevi n. sp. (Platyhelminthes: Monogenea) from the Mediterranean Sea and Black Sea: two new members of the cross-ocean distributed Gyrodactylus orecchiae species group.

Gyrodactylus sphinx Dmitrieva & Gerasev, 2000 is the only species of Gyrodactylus originally described from Aidablennius sphynx (Valenciennes) in the Black Sea. In the present study, monogeneans similar to G. sphinx are reported from the same host and from two other species of Blenniidae from the Black Sea, as well as from the Mediterranean Sea. This study aims to verify the taxonomic status of the specimens found in different hosts and localities, other than the type ones of G. sphinx. Twenty-two measurements of the haptoral structures of 169 gyrodactylids were used for the morphological study. Morphometric variability between different samples was analysed using analysis of variance, multivariate analysis of variance (MANOVA) and principal component analysis (PCA). Molecular studies were carried out using the nuclear internal transcribed spacer 2 and 5.8S ribosomal DNA regions. Network, Bayesian phylogenetic and species delimitation analyses were performed to infer the number of taxonomic units and the phylogeographic relationships occurring within and among them. MANOVA revealed a significant dependence of the morphometry of hamuli and marginal hooks on host species and regions, but a clear differentiation between samples was not confirmed by PCA. Moreover, the ranges of all dimensions overlapped between samples. However, molecular analyses suggested the occurrence of at least two taxonomic entities. The most common entity was present in individuals of the Black and Mediterranean seas, and is described here as Gyrodactylus gerasevi n. sp., whereas a second entity recognized as a G. sphinx was found only in individuals from two localities off Crimea. The monophyletic cluster grouping of these two species was placed within a large clade that also included a separate sister cluster with seven other species of the Gyrodactylus orecchiae cross-ocean species group.

Intestinal granular cells of a cartilaginous fish, thornback ray Raja clavata: Morphological characterization and expression of different molecules.

This investigation aims to fill gaps in our understanding of the intestinal immune cells of elasmobranchs. Whole digestive tracts of fifteen thornback ray Raja clavata were provided by a trawl fleet from the Gulf of Asinara (Sardinia, western Mediterranean Sea). Histochemical, immunohistochemical and ultrastructural observations were conducted on the spiral intestine. Three types of granular cells were identified; type I in epithelium, types II and III in lamina propria-submucosa, with each of them containing cytoplasmic granules with different ultrastructural characteristics. Data on size and density of each granular cell type are provided. Immunostaining of intestinal sections showed the reactivity of the granular cells: type I cells were positive for lysozyme, mast cell tryptase and tumor necrosis factor-ɑ based on antibody staining; type III cells were immune-reactive to anti-interleukin 6 antibody, whilst type II cells were negative to all the antibodies used. Comparison of each granular cell type with immune cells of teleosts or mammals and an hypothesis on their nature and function are reported. A potential role for granular cells in intestinal cellular immunity is also discussed with respect to type I and type III cells having similarities to Paneth cells and neutrophils, respectively.

Metazoan parasites in the head region of the bullet tuna Auxis rochei (Osteichthyes: Scombridae) from the western Mediterranean Sea.

The head region of 72 bullet tuna Auxis rochei from the western Mediterranean Sea (south-east Spain and the Strait of Gibraltar) was examined for parasites. Seven metazoan species were found in the fish from south-east Spain: three monogeneans, two trematodes and two copepods, whereas only three species were isolated in the fish from the Strait of Gibraltar. A comparison of the levels of infection of the parasites according to fish size in south-east Spain showed that the prevalence of Didymozoon auxis and the mean abundance of Allopseudaxine macrova were higher in the larger hosts (range of fork length = 38-44 cm) than in the smaller ones (33-37 cm). A comparison of the parasite infections according to geographical region showed that the mean abundances of Nematobothriinae gen. sp. and Caligus bonito were higher in fish from south-east Spain than in those from the Strait of Gibraltar. A comparison of the parasite fauna of A. rochei from the Mediterranean Sea with the published data on Auxis spp. from the Atlantic, Indian and Pacific Oceans revealed the closest similarity between the Mediterranean A. rochei and the Atlantic A. thazard.

Molecular and epidemiological data on Anisakis spp. (Nematoda: Anisakidae) in commercial fish caught off northern Sardinia (western Mediterranean Sea).

Anisakiasis is a fish-borne zoonosis caused by third stage larvae of the nematode Anisakis sp. present in fish or cephalopods. This is the first contribution to the molecular identification and epidemiology of Anisakis spp. in commercial fish from the Gulf of Asinara (Sardinia, western Mediterranean Sea). Between April 2006 to November 2011, 777 specimens of 10 fish species (Engraulis encrasicolus, Merluccius merluccius, Micromesistius poutassou, Phycis blennoides, Sardina pilchardus, Sardinella aurita, Scomber colias, Sphyraena viridensis, Trachurus mediterraneus, Trachurus trachurus) were examined for Anisakis sp. larvae. A total of 1286 larvae were found in 218 fish. The great majority of larvae were located in the body cavity, and only a small part (60, 4.7%) in the muscle. All the Type I larvae (1272) were identified as Anisakis pegreffii and all the Type II (14) as Anisakis physeteris, confirming that A. pegreffii is the dominant species and the most important agent of human anisakiasis in the western Mediterranean Sea.