Carbohydrate patterns in the digestive tract of Sparus aurata L. and Psetta maxima (L.) (Teleostei) parasitized by Enteromyxum leei and E. scophthalmi (Myxozoa)

33 p., figuras, tablas y bibliografíaThe influence of Enteromyxum spp. infections on the carbohydrate patterns of the digestive tract of gilthead sea bream (GSB) Sparus aurata L. and turbot (TB) Psetta maxima (L.) has been studied. Histochemical stainings to differentiate the types of mucins and lectin-binding assays to detect terminal carbohydrate residues were applied to histological sections of GSB and TB uninfected or infected by Enteromyxum leei and E. scophthalmi, respectively. The number of intestinal GC decreased in severely infected fish in both parasitoses, though changes in mucin patterns were limited to the decrease in the staining intensity for acidic mucins in infected GSB. The TB stomach and intestine lacked histochemically detectable acidic mucins, or sialic acid detectable by SNA, in contrast with their abundance in GSB. Glucose/mannose, fucose and GlcNAc residues were less abundant in both infected hosts with respect to uninfected fish. In contrast, D-Gal and D-GalNAc moieties (detectable by BSL I) increased in most parts of E. scophthalmi-infected TB while decreasing (oesophagus) or remaining unchanged (intestine) in E. leei-infected GSB. The decreasing in the expression of acidic mucins and of sialic acid detectable by SNA in E. leei-infected GSB is remarkable. Differences in the carbohydrate patterns between both hosts could aid to explain the differences in the severity of both enteromyxoses. In addition, the changes induced by Enteromyxum spp. infections in the digestive tract of GSB and TB suggest a role of terminal carbohydrate residues in the parasite-host interaction.Funding for this work was obtained from the Spanish Ministry of Science and Education through the research project AGL2006-13158-C01. M. J. Redondo is recipient of a CSIC I3P contract funded by the European Social Fund.Peer reviewe

Novel horizontal transmission route for Enteromyxum leei (Myxozoa) by anal intubation of gilthead sea bream Sparus aurata

11 p., il., bibliografíaThe aim of the present study was to determine whether Enteromyxum leei, one of the most threatening parasitic diseases in Mediterranean fish culture, could be transmitted by peranal intubation in gilthead sea bream Sparus aurata L. Fish were inoculated either orally or anally with intestinal scrapings of infected fish in 3 trials. Oral transmission failed, but the parasite was efficiently and quickly transmitted peranally. Prevalence of infection was 100% at 60 d post inoculation (p.i.) in Trial 1 under high summer temperature (22 to 25°C; fish weight = 187.1 g), and 85.7 % in just 15 d p.i. in Trial 3 using smaller fish (127.5 g) at autumn temperature (19 to 22°C). In Trial 2, prevalence reached 60% at 60 d p.i. in the group reared at constant temperature (18°C), whereas no fish was infected in the group that was kept at low winter temperature (11 to 12°C), although infection appeared (46.1 % at 216 d p.i.) when temperature increased in spring. The arrested development at low temperature has important epidemiological consequences, as fish giving false negative results in winter can act as reservoirs of the parasite. Histopathological examination showed a posterior-anterior intestinal gradient in the progression of the infection, in terms of both intensity and parasite maturation. Thus, peranal intubation provides a very uniform, reliable and faster mode of transmission of E. leei than the commonly used transmission methods (cohabitation, exposure to infected effluent and oral inoculation), which require long exposure times or give variable and unpredictable results.This work was funded by the Spanish Ministerio de Educación y Ciencia (MEC) (AGL2006-13158-C03-01) and Ministerio de Ciencia e Innovación (AGL2009-13282-C02-01). Additional funding was obtained from the ‘Generalitat Valenciana’ (research grant PROMETEO 2010/006). I.E. received a Spanish FPI-PhD fellowship from MEC.Peer reviewe

Definition of a list of fish diseases to aid health management in Spain

Trabajo presentado en la 14th EAFP International Conference (European Association of Fish Pathologists), celebrada en Praga (República Checa), del 14 al 19 de septiembre de 2009An expert working group used a risk ranking technique to compile a list of fish disease hazards (pathogens) of relevance to Spanish aquaculture. It was possible to divide the list into three groups: I-high national risk; II-regional risk; III-low risk. The three groups were as follows: Group I (high risk) Aphanomyces invadans (EUS)**, spring viraemia of carp virus (SVCV), koi herpes virus (KHV)¿ and infectious haematopoietic necrosis virus (IHNV)¿ Group II (regional risk) Enteromyxum spp. (leei and scophthalmi), Aquabirnaviridae (incl. IPNV), viral encephalopathy and retinopathy virus (VERV), Streptococcus iniae, Philasterides dicentrarchi and Aeromonas salmonicida (in the marine environment). Group III (low risk) Sparicotyle chrysophrii/Microcotylidae, Flavobacterium maritimus, Photobacterium piscicida, Togaviridae, Sphaerospora testicularis, Edwardsiella tarda, Birnavirus (no-EVE), Lactococcus garviae, viral haemorrhagic septicaemia virus (VHSV)¿, Tenacibaculum maritimum, epizootic haematopoietic necrosis virus (EHNV)**, Renibacterium salmoninarum (BKD) and Gyrodactylus salaris. The exercise formed part of a project concerning aquaculture health management (Jacumar-GESAC¿) in Spain and is being used to help define sampling plans for disease monitoring using epidemiological and risk-based criteria. **The diseases caused by these pathogens are notifiable and exotic according to Directive 2006/88/EC ¿The diseases caused by these pathogens are notifiable and non-exotic according to Directive 2006/88/EC ¿Plan Nacional de Cultivos Marinos; Gestión sanitaria de la acuicultura: Adaptación a la nueva normativa (GESAC) ¿ financed by the Junta Nacional Asesora de Cultivos Marinos (Jacumar

Lectinhistochemical detection of terminal carbohydrate residues in the enteric myxozoan Enteromyxum leei parasitizing gilthead seabream Sparus aurata (Pisces: Teleostei): a study using light and transmission electron microscopy

9 p., 26 figures, 4 tables and bibliographyThe presence of terminal carbohydrate residues in Enteromyxum leei (Diamant, Lom et Dyková, 1994) Palenzuela, Redondo et Álvarez-Pellitero, 2002 stages in gilthead seabream intestines was studied at light microscopy (LM) and transmission electron microscopy (TEM) level using lectin histochemical techniques. Abundant mannose and/or glucose residues were demonstrated by the intense staining caused by binding of biotinylated concanavalin A (Con A), at both LM and TEM. A clear positivity was also obtained with Ulex europaeus (UEA I) agglutinin specific for fucose residues. Both lectins stained E. leei proliferative and sporogonic stages, though glycan patterns varied between these developmental stages. Wheat germ agglutinin (WGA) and Bandeiraea simplicifolia lectin I (BSL I) recognised only structures in the sporogonic stages. Faint labelling occurred with Glycine max (SBA) lectin. No staining was obtained with Sambucus nigra (SNA) agglutinin. The TEM studies demonstrated a restricted presence of N‑acetyl-D-galactosamine and α-D-galactose, whereas glucose/mannose and fucose, the dominant structures, were also present at the parasite membranes and host-parasite interface, suggesting a role in host-parasite interaction.Funding for this work was obtained from the Spanish Ministry of Science and Education through the research project AGL2006-13158-C01. M. J. Redondo is recipient of a CSIC I3P contract funded by the European Social Fund.Peer reviewe

The effect of lectins on the attachment and invasion of Enteromyxum scophthalmi (Myxozoa) in turbot (Psetta maxima L.) intestinal epithelium in vitro

21 p., figuras y bibliografíaThe involvement of the lectin/carbohydrate interaction in the invasion of the turbot intestinal epithelium by Enteromyxum scophthalmi was studied in vitro using explants of turbot intestine and pre-treatment of parasite stages with the plant lectins of Canavalia ensiformis (Con A) and Glycine max (SBA). Both lectins inhibited the attachment and invasion of E. scophthalmi stages to the intestinal epithelium, though the inhibitory effect was higher for SBA than for Con A. Such results point to the involvement of N-acetyl-galactosamine (GalNAc) and galactose (Gal) residues and also of mannose/glucose residues in the E. scophthalmi-intestinal epithelium interaction. The inhibitory effect of both lectins on the parasite adhesion and penetration points to the interest of further studies to confirm the presence of putative lectins recognising GalNAc-Gal and mannose/glucose residues in turbot intestine. The obtained results demonstrated also the adequacy of turbot intestinal explants as an in vitro model to study the interaction with E. scophthalmi.This work was supported by the Spanish Ministry of Science and Education through the research projects AGL2006-13158-C01 and AGL2009-13282-C02-01. María J. Redondo is recipient of a CSIC I3P contract funded by the European Social Fund.Peer reviewe

Mucosal intestinal immunity and response to parasite infections in ectothermic vertebrates

As part of the mucosal immune system, the intestine plays a paramount role in the immune response in all vertebrates. The mucosal immunity includes inductive and effector tissues, and effector cells and molecules, all part of both innate and adaptive immunity and their connections. The digestive tract is the target organ of many parasites. In ectotherms, intestinal parasites include mainly flagellates, apicomplexans, myxozoans and helminths. The gut mucosal epithelium acts as a protective barrier against pathogens. Intestinal mucins and terminal carbohydrate residues are involved in the first contact pathogen-host, in some occasions through interaction with parasite lectins, as illustrated by mammalian and reptile Entamoeba spp. Mucins and their glycosylation patterns can change in reponse to intestinal parasites, including several piscine myxozoans and helminths. In addition, different pathogen recognizing receptors (PRRs) are sensed by the pathogen-associated molecular patterns (PAMPs) of invading pathogens. Although several PRRs have been thus far identified in ectotherms, little or no information is available on their presence in the intestine or on their involvement in parasite recognition. However, in mammals, several PRRs, mainly Toll-like receptors (TLRs) and nucleotide-binding oligomerization domains (NODs) play a significant role at the intestinal level by sensing pathogens and controlling inflammation and apoptosis, thus contributing to the maintenance of homeostasis. Several molecules and factors related to acute phase response (APR), such as AMPs, lysozyme, lectins, complement, cytokines and antiproteases can be activated at the gut level, in connection with innate and adaptive immune factors. Cellular components are also crucial in the intestinal immune response, and they include intestinal epithelial leucocytes (IECs), dendritic cells, macrophages, granulocytes and intraepithelial lymphocytes (IELs), all of them interacting at both the mucosal and systemic levels, to orchestrate an integrated immune response. The cross-talk between the different cellular types, involving also TLRs, AMPs, cytokines and other factors is well known in endotherms. The cellular reactions to several mammalian intestinal parasites are also well characterized. However, information is much scarcer for ectotherms. Although several types of immune cells (EGC/mast cells, other ganulocytes, rodlet cells (RCs), T and B cells, neuroendocrine cells) have been identified (mainly in teleosts), these cells are not well characterized and the knowledge of the different T cells subsets is in its infancy. In addition, though inflammatory reactions to several intestinal studied parasites have been reported, the cellular responses have been characterized for few species, mainly Enteromyxum spp. Available information points to the relevant role of RCs and EGCs/mast cells, but the cellular types have not been fully characterized, and the involvement of other granulocytes remains to be elucidated. In addition, the T and B cell responses and the role of secretory immunoglobulins are poorly known

Helmintocenosis del tracto digestivo de la trucha en los ríos de León

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Helmintos de peces continentales españoles

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Fish immunity and parasite infections: from innate immunity to immunoprophylactic prospects

The increasing economic importance of fish parasitoses for aquaculture and fisheries has enhanced the interest in the defence mechanisms against these infections. Both innate and adaptive immune responses are mounted by fish to control parasite infections, and several mechanisms described for mammalian parasitoses have also been demonstrated in teleosts. Innate immune initiation relies on the recognition of pathogen-associated molecular patterns (PAMPs) by pathogen recognizing receptors (PRRs). A number of PRRs, mainly Toll-like receptors (TLRs), have been characterized in fish, and some molecules susceptible of functioning as PAMPs are known for some fish parasites. A lectin-carbohydrate interaction has also been described in some host fish-parasite systems, thus probably involving C-type lectin receptors. Inflammatory reactions involving cellular reactions, as phagocytosis and phagocyte activity (including oxidative mechanisms), as well as complement activity, are modulated by many fish parasites, including mainly ciliates, flagellates and myxozoans. Besides complement, a number of humoral immune factors (peroxidases, lysozyme, acute-phase proteins) are also implicated in the response to some parasites. Among adaptive responses, most data deal with the presence of B lymphocytes and the production of specific antibodies (Abs). Although an increasing number of T-cell markers have been described for teleosts, the specific characterization of those involved in their response is far from being obtained. Gene expression studies have demonstrated the involvement of other mediators of the innate and adaptive responses, i.e., cytokines [interleukins (IL-1, IL-8), tumor necrosis factor (TNF), interferon (IFN)], chemokines (CXC, CC), as well as several oxidative enzymes [inducible nitric oxide synthase (iNOS), cyclo-oxygenase 2 (COX-2)]. Information is scarcer for factors more directly linked to adaptive responses, such as major histocompatibility (MH) receptors, T cell receptors (TCRs) and IgM. Expression of some immune genes varied according to the phase of infection, and proinflammatory cytokines were mainly activated in the early stages. Gene expression was generally higher in the target tissues for some skin and gill parasites, as Ichthyophthirius multifiliis, Neoparamoeba spp. and Lepeophtheirus salmonis, thus confirming the relevance of mucosal immunity in these infections. The existence of protective responses has been demonstrated for several fish parasites, both in natural infections and in immunization studies. Most information on the mechanisms involved in protection deals with the production of specific Abs. Nevertheless, their levels are not always correlated to protection, and the precise involvement of immune mechanisms in the response is unknown in many cases. No commercial vaccine is currently available for piscine parasitoses, although experimental vaccines have been assayed against I. multifiliis, Cryptobia salmositica and scuticociliates. The known information points to the need for integrated studies of the mechanisms involved in protection, in order to choose the optimum antigen candidates, adjuvants and formulations. © 2008 Elsevier B.V. All rights reserved.Part of the information included in the present review has been generated through there search project AGL2006-13158-C02-01 funded by the Spanish Ministerio de Educación y CienciaPeer Reviewe

Variaciones estacionales de las infestacions por Cystidicoloides tenuissima en truchas (Salmo trutta m. fario) de los ríos de la provincia de León

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