New insights into the coexistence of Contracaecum rudolphii A and Contracaecum rudolphii B (Nematoda: Anisakidae) in Phalacrocorax carbo sinensis from Sardinia: genetic variability and phylogenetic analysis.

Contracaecum sp. nematodes are important parasites of fish eating birds that can cause animal health problems. In the present study, specimens of Contracaecum rudolphii sensu lato, from the great cormorant Phalacrocorax carbo sinensis from Sardinia, were characterized based on morphological and molecular data. The morphological analysis allowed to identify all the fourth stage larvae (n = 1918) as Contracaecum sp., and adults, male (n = 5845) and female (n = 8312), as C. rudolphii sensu lato. Population genetics and phylogenetic relationships were inferred based on mitochondrial and nuclear markers. Multiple sequence alignment of the ribosomal internal transcribed spacer showed the coexistence of C. rudolphii A (n = 157), C. rudolphii B (n = 22) and a rare heterozygote of these species. Moreover, mitochondrial markers, namely NADH dehydrogenase subunits I (nad1), cytochrome c oxidase subunit (cox1 and cox2) and small subunit of rRNA (rrnS), showed that the studied C. rudolphii A populations had undergone bottleneck, or founder effect event, subsequent to a rapid population growth and expansion. The observed heterozygote is with a mitochondrial pattern of C. rudolphii B. Although, both Contracaecum species showed high genetic diversity, no genetic structure between localities was detected. Phylogenetic reconstructions supported the paraphyly of the avian Contracaecum species including C. ogmorhini (parasite of otariids).

Epidemiological and molecular data on heterophyid trematode metacercariae found in the muscle of grey mullets (Osteichthyes: Mugilidae) from Sardinia (western Mediterranean Sea).

This study is a contribution to the molecular taxonomy and epidemiology of heterophyid (Trematoda: Heterophyidae) metacercariae found in the muscle of Mugilidae (Osteichthyes) from Sardinia (western Mediterranean Sea). Sixty specimens of mugilids (13 Chelon labrosus, 18 Liza aurata, 6 Liza ramada, 8 Liza saliens, 15 Mugil cephalus) were examined and 17,899 metacercariae isolated in 95 % of the hosts. Four types of metacercariae were identified: Heterophyes sp. (n = 14,113), Heterophyes sp. -small (1225), Stictodora sp. (1606), and Ascocotyle (Phagicola) sp. (955). The experimental infection of a hamster with Heterophyes sp. metacercariae produced six adults identified as Heterophyes heterophyes and two as Heterophyes cf. nocens. The morphology of Heterophyes sp. -small metacercariae matched with that of Heterophyes dispar. The sequence analysis of the ITS2 and 28S portions of rDNA confirmed the morphological identification of metacercariae, showing four clusters. All adults grouped together with the Heterophyes sp. metacercariae, whereas adults of Heterophyes nocens from Korea clustered separately, showing that this species is distinguished from H. heterophyes, and suggesting caution in the exclusive use of the number of rodlets of the genital sucker to separate the two species. The presence of metacercariae was high in all hosts; the highest prevalence is of Heterophyes sp. (prevalence ≥78 %; mean intensity ≥135 metacercariae/100 g muscle), and the most heavily infected host is M. cephalus (prevalence = 100 %; mean intensity = 841 metacercariae/100 g muscle).

Genetic characterization of Fasciola hepatica from Tunisia and Algeria based on mitochondrial and nuclear DNA sequences.

Fasciolosis caused by Fasciola spp. (Platyhelminthes: Trematoda: Digenea) is considered the most important helminth infection of ruminants in tropical countries, causing considerable socioeconomic problems. In the present study, samples identified morphologically as Fasciola hepatica from sheep and cattle from different geographical locations of Tunisia and Algeria were genetically characterised by sequences of the first (ITS-1), the 5.8S and second (ITS-2) Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA (rDNA) and mitochondrial Cytochrome c Oxidase subunit I (COI) gene. Comparison of the ITS and COI sequences of the North African samples with sequences of Fasciola spp. from GenBank confirmed that all samples from Tunisia and Algeria samples belong to a single species, namely F. hepatica. Several specimens from Tunisia and Algeria showed a substitution C/T in position 859 in the ITS-2 sequences, previously reported from Spain, suggesting that the above mentioned variant may have a common origin and spread recently throughout the three countries because of movement of infected animals. This is the first molecular characterization of F. hepatica in North Africa which provides a foundation for further studies on Fasciola spp. in Tunisia and Algeria.

Occurrence of Nematodes of the Genus Anisakis in Mediterranean and Atlantic Fish Marketed in Sardinia.

Anisakiasis is a gastrointestinal fish-borne zoonosis caused by the ingestion of third stage larvae of the genus Anisakis. Between January and December 2013, 1112 specimens of four commercial fish species (Engraulis encrasicolus, Merluccius merluccius, Scomber colias and Trachurus mediterraneus) marketed in Sardinia (Italy) were examined for Anisakis sp. The overall prevalence of Anisakis spp larvae was 39.9%, all morphologically identified as Type I. Scomber colias showed the highest prevalence (100%), followed by M. merluccius (Atlantic 91.0%, Mediterranean 71.2%), T. mediterraneus (32.7%) and E. encrasicolus (25.9%). All the larvae found in Mediterranean hosts were genetically identified as Anisakis pegreffii, whereas 90.0% of the larvae found in the Atlantic M. merluccius belonged to Anisakis simplex sensu stricto and 10.0% to A. pegreffii. The mean abundance of Anisakis sp. larvae was positively correlated with fish size in E. encrasicolus, Atlantic M. merluccius and local M. merluccius. The prevalence of infection was greater in the body cavity (37.9%) than in the edible muscle (9.4%). However, 1.8% of the examined fish were infected exclusively in the muscle. Therefore, the risk associated to the consumption of raw or undercooked fishery products poses the need of measures such as visual inspection and preventive treatments to guarantee consumers' health.

Parasites of the head of Scomber colias (Osteichthyes: Scombridae) from the western Mediterranean Sea.

The metazoan parasite assemblage of the head of 30 specimens of the Atlantic chub mackerel (Scomber colias) from the western Mediterranean Sea was analysed. Eight species of parasites were found, four mazocraeid monogeneans: Grubea cochlear (prevalence = 10%), Kuhnia scombercolias (59%), K. scombri (52%), Pseudokuhnia minor (86%); three didymozoid trematodes: Nematobothrium cf. faciale (21%), N. filiforme (41%), N. scombri (7%); and one laerneopodid copepod: Clavelissa scombri (7%). Results were compared with previously published data from 14 localities of the eastern Mediterranean Sea and the Atlantic Ocean, using non-parametric univariate and multivariate analyses, and the whole parasite fauna of S. colias was compared with that of the congeners (S. australasicus, S. japonicus and S. scombrus). Parasites showed to reflect the biogeographical and phylogenetic history of host. From a methodological point of view, the use of both non-parametric univariate and multivariate techniques proved to be effective tools to detect dissimilarities between parasite assemblages.