Ciclo evolutivo de brachylaemus nitallae dujardin in dollfus, 1986 (tremotada: brachylaemidae) en Formetera (Islas Pitiusas)

Tesi de Llicenciatura per a la obtenció del Grau de Biologia. Facultat de Biologia. Departament d'Ecologia . Universitat de Barcelona. Director: Ramón Margalef López. 197

Biogeography of Anisakis (Anisakidae) and Hysterothylacium (Rhaphidascarididae) nematode species in consumed fish

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/128014The presence of ascaridoid nematodes in commonly consumed fish constitutes an important health risk for humans as well as an economic problem for fisheries. Here, information is provided on the taxonomic status of the representative “anisakid-related” species of the families Anisakidae and Raphidascarididae. These parasites have a worldwide marine geographical distribution, mainly related to the presence of the vertebrate hosts involved in their life cycle. Morphological and molecular methods currently used for specific characterization of larval and adult nematode specimens are analysed and discussed. This study is focused on the taxonomy and parasite-host distribution of species of the genera Anisakis and Hysterothylacium from the North-East Atlantic Ocean and Mediterranean Sea regions

Estimation of the number of Anisakis larvae in commercial fish using a descriptive model based on real-time PCR

BACKGROUND: Seafood parasitation by Anisakis (Anisakidae) larvae has been reported in most of the oceans and seas worldwide.The presence of these nematodes in commonly consumed fish represents a potential hazard for consumers as they can provoke gastrointestinal symptoms and allergic reactions. In the present work, the capacity of a SYBR Green qPCR protocol to quantify Anisakis larvae in commercial fish was evaluated using experimentally spiked samples with different numbers (0-50) of A. simplex third-stage larvae (L3). To verify the agreement of the obtained results, 25 naturally infected fish specimens of Atlantic blue whiting underwent a parallel visual inspection. RESULTS: The logarithmic behavior of the Cq data obtained from the experimentally spiked samples allowed the development of a descriptive mathematical model that correlates the Cq value with the number of Anisakis larvae (R2 = 0.9908, CV = 2.37%). In the commercial blue whiting specimens there was a high correlation between the results of the molecular technique and the visual inspection (R2 = 0.9912); the Bland-Altman analysis showed that 94% of the differences were within the limits of agreement (−4.98 and 6.68), indicating the reliability of the descriptive mathematical model based on the SYBR Green qPCR technique. CONCLUSION: The descriptive function presented based on the SYBR Green qPCR assay is promising as a sensitive and accurate tool for measuring the Anisakis larval load in commercial fish, with a potential application not only in the food industry but also in prevention programs for public health

Anisakis and Hysterothylacium species in Mediterranean and North-East Atlantic fishes commonly consumed in Spain: Epidemiological, molecular and morphometric discriminant analysis

The consumption of raw fish parasitized with larval ascaridoid nematodes of the family Anisakidae can cause anisakiasis, provoking gastrointestinal and/or allergic symptomatology. The main causative agents in the Anisakis genus are the sibling species Anisakis simplex sensu stricto (s.s.) and A. pegreffii of the A. simplex sensu lato (s.l.) complex. Larvae of A. simplex (s.l.) are frequently detected in fish commonly consumed in Spain, as are larvae of the genus Hysterothylacium of the family Raphidascarididae, associated with allergic reactions but not considered pathogenic. Reported here are the results of an epidemiological survey of ascaridoid larvae in three commonly consumed fish species in Spain, horse mackerel (Trachurus trachurus) (n = 52), blue whiting (Micromesistius poutassou) (n=93) and anchovy (Engraulis encrasicolus) (n=69), caught in the North-Eastern Atlantic, West Mediterranean and Adriatic Sea. The larvae found in the dissected fish were identified in the following order of abundance: A. simplex (s.l.) (n=2003), Hysterothylacium aduncum (n=422), H. fabri (n=180) and A. physeteris (n=15). Binomial regression analysis showed a correlation between A. simplex (s.l.) and Hysterothylacium larvae abundance and the host geographical location, the North-Eastern Atlantic being the area with the highest parasitation. Fish length and weight and Fulton's condition factor were correlated with A. simplex (s.l.) abundance only in horse mackerel. There was a significant presence of A. simplex (s.l.) and H. aduncum larvae in the musculature of North-Eastern Atlantic blue whiting, the most parasitized part being the anteroventral region, followed equally by the anterodorsal and central sections. The ITS rDNA of larvae of the sibling species A. simplex (s.s.) and A. pegreffii was identified by PCR-RFLP, and a binary logistic regression model was developed to study their morphometric differentiation. Anisakis simplex (s.s.) was detected in the North- Eastern Atlantic and A. pegreffii in all the areas studied. The morphometric analysis discriminated between the two species at the third and fourth larval stages (L3 and L4), the latter obtained by in vitro culture in RPMI-1640 medium. Two discriminant functions were obtained for the L3 and L4 larvae, the ventricle being a key parameter for specific differentiation in both stages, providing taxonomical criteria that could be used besides molecular identification. The present study reveals differences in the parasitation of the studied fish, including the distribution of larvae in the musculature, related to the host species and its geographical origin

Hybrid Genotype of Anisakis simplex (s.s.) and A. pegreffii Identified in Third- and Fourth-Stage Larvae from Sympatric and Allopatric Spanish Marine Waters

The sibling species Anisakis simplex (s.s.) and Anisakis pegreffii are parasites of marine mammals and fish worldwide and the main causative agents of human anisakiasis. In sympatric areas, a hybrid genotype between the two species has been identified, mainly in third-stage larvae, but rarely in fourth-stage and adult forms. The aim of this study was to confirm the presence of hybrid genotypes in larvae parasitizing fish caught in sympatric and allopatric Spanish marine waters, the North-East Atlantic and West Mediterranean, respectively, and to study possible differences in the growth behaviour between genotypes. Of the 254 molecularly analysed larvae, 18 were identified as hybrids by PCR-RFLP analysis of the rDNA ITS region, 11 of which were subsequently confirmed by EF1 α-1 nDNA gene sequencing. These results therefore indicate an overestimation of hybrid genotypes when identification is based only on the ITS region. We also report the detection of a hybrid specimen in a host from the West Mediterranean, considered an allopatric zone. Additionally, fourth-stage larvae with a hybrid genotype were obtained in vitro for the first time, and no differences were observed in their growth behaviour compared to larvae with A. simplex (s.s.) and A. pegreffii genotypes

Genetic diversity of Contracaecum rudolphii sp. A (Nematoda: Anisakidae) parasitizing the European Shag Phalacrocorax aristotelis desmarestii from the Spanish Mediterranean coast

Sibling species of the Contracaecum rudolphii (s.l.) complex are habitual endoparasites of cormorants of the Phalacrocoracidae family, worldwide. In Europe, the two species, C. rudolphii sp. A and C. rudolphii sp. B, have been identified. However, information regarding the occurrence and distribution of these anisakids in cormorants from Spain is scarce. In the present study, 20 specimens of the European Shag, Ph. aristotelis desmarestii, from the western Mediterranean Spanish marine coast were parasitologically analyzed for the presence of nematodes. All hosts were found parasitized with Contracaecum specimens (n D 1,517). A representative subsample was genetically identified as C. rudolphii sp. A by sequence analysis of the mtDNA cox2 gene and the ITS1 and ITS2 regions of the rDNA. This represents the first report of C. rudolphii sp. A from the Spanish Mediterranean waters. Population genetic analysis was performed including other C. rudolphii sp. A specimens from the west Sardinian and the Tyrrhenian Sea. At the intraspecific level, a significant genetic dierentiation (Fst 0.08, p < 0.00001) between the metapopulation from the Spanish Mediterranean coast and that from the Sardinian waters was observed; whereas, no dierentiation was found between metapopulations of the parasite from the Spanish and the Tyrrhenian Italian coast. The findings highly support the hypothesis of the adaptation of the life cycle of C. rudolphii sp. A in brackish and marine ecosystems. Furthermore, the results on the population genetics of C. rudolphii sp. A suggest the possible role of the migration routes of wintering populations of cormorants in the Mediterranean Sea in influencing the parasite genetic structure

First Molecular Diagnosis of Clinical Cases of Gastric Anisakiosis in Spain

Anisakiosis is a fish-borne disease with gastrointestinal and/or allergic symptoms caused by the consumption of raw or undercooked fish parasitized with nematode larvae of the genus Anisakis. In Europe, Anisakis pegre i has been detected as the causative agent, although the sibling species Anisakis simplex sensu stricto (s.s.) is also known to cause the disease in other parts of the world, and discrepancies exist regarding their respective pathogenic potential. In Spain a high number of cases has been recorded, with marinated anchovies being the main source of infection, although no specific diagnosis has been documented in humans. In this study, we analyzed three cases of anisakiosis in patients from Barcelona (Spain) who had consumed undercooked hake. All patients described epigastric pain and several larval nematodes were removed endoscopically from their stomachs. Larvae were morphologically characterized as third-stage larvae of Anisakis simplex sensu lato (s.l.) and molecularly identified as A. simplex (s.s.) by means of PCR RFLP of the ITS region of the rDNA and sequencing of the elongation factor1 alpha1 (EF1 -1) nDNA gen. This study represents the first specific identification of Anisakis larvae in clinical cases of anisakiosis reported in Spain. Specific molecular diagnosis is of crucial importance for assessing the health risk of Anisakis sibling species. Hake consu

Revisión de la biología y ecología de la familia Brachylaimidae Joyeux et Foley, 1930 (Trematoda: Digenea) con especial énfasis en las especies parásitas de mamíferos

[spa] La finalidad de la presente obra es la de contribuir al conocimiento de la biología y ecología de los Digénidos representantes de la familia Brachylaimidae, mediante el estudio detallado del ciclo vital y de la evolución de los estadíos larvarios y adulto de distintas especies parásitas de Mamíferos (Insectívoros y Roedores) y la revisión de cuantos datos sobre biología y ecología de Brachyláimidos cabe encontrar en la literatura publicada hasta la fecha. Para ello hemos efectuado una división en cuatro grandes capítulos. El primero se ha destinado a una exposición detallada de los materiales analizados y de los métodos y técnicas empleados en el estudio. El segundo capítulo versa sobre los antecedentes, concretamente los conocimientos actuales sobre biología y ecología de Brachylaimidae existentes en la bibliografía. El tercer capítulo concierne a la exposición de nuestros trabajos parasitológicos, llevados a cabo tanto en la Naturaleza como experimentalmente en el Laboratorio, y que constituyen nuevas aportaciones sobre la biología y ecología de especies de la familia Brachylaimidae. El cuarto y último capítulo sirve a modo de colofón y va destinado a efectuar la discusión global de los trabajos efectuados y su comparación con los antecedentes bibliográficos y a exponer las conclusiones generales finales

Biogeography of Anisakis (Anisakidae) and Hysterothylacium (Rhaphidascarididae) nematode species in consumed fish

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/128014The presence of ascaridoid nematodes in commonly consumed fish constitutes an important health risk for humans as well as an economic problem for fisheries. Here, information is provided on the taxonomic status of the representative “anisakid-related” species of the families Anisakidae and Raphidascarididae. These parasites have a worldwide marine geographical distribution, mainly related to the presence of the vertebrate hosts involved in their life cycle. Morphological and molecular methods currently used for specific characterization of larval and adult nematode specimens are analysed and discussed. This study is focused on the taxonomy and parasite-host distribution of species of the genera Anisakis and Hysterothylacium from the North-East Atlantic Ocean and Mediterranean Sea regions

Biogeography of Anisakis (Anisakidae) and Hysterothylacium (Rhaphidascarididae) nematode species in consumed fish

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/128014The presence of ascaridoid nematodes in commonly consumed fish constitutes an important health risk for humans as well as an economic problem for fisheries. Here, information is provided on the taxonomic status of the representative “anisakid-related” species of the families Anisakidae and Raphidascarididae. These parasites have a worldwide marine geographical distribution, mainly related to the presence of the vertebrate hosts involved in their life cycle. Morphological and molecular methods currently used for specific characterization of larval and adult nematode specimens are analysed and discussed. This study is focused on the taxonomy and parasite-host distribution of species of the genera Anisakis and Hysterothylacium from the North-East Atlantic Ocean and Mediterranean Sea regions