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

Ultrastructural localisation of carbohydrates in four myxosporean parasites

The existence and localisation of carbohydrates in four myxosporean parasites was investigated at transmission electron microscope, using lectin histochemistry techniques. The Myxosporea studied showed different lectin binding patterns. N-acetylglucosamine or its polymers were predominant in the valves of Leptotheca sp. and were also present in Sphaerospora dicentrarchiand Polysporoplasma sparis ones. Mannose and/or glucose terminals were mainly detected in S. dicentrarchi and P. sparis valves. Polar capsule walls were intensively recognised by Con-A in S. dicentrarchi and with medium intensity in P. sparis and Leptotheca sp. The polar filament was scarcely labelled except in Leptotheca sp. with BS-I. The sporoplasms of the studied parasites were stained with all the lectins tested with each myxosporea, except those of Leptotheca sp. with BS-I. Some structures of the developmental stages of Zschokkella mugilis and Leptotheca sp. were stained with BS-I. The possible role of these carbohydrate terminals found in the studied Myxosporea is discussed

Ultrastructural localisation of carbohydrates in four myxosporean parasites

The existence and localisation of carbohydrates in four myxosporean parasites was investigated at transmission electron microscope, using lectin histochemistry techniques. The Myxosporea studied showed different lectin binding patterns. N-acetylglucosamine or its polymers were predominant in the valves of Leptotheca sp. and were also present in Sphaerospora dicentrarchiand Polysporoplasma sparis ones. Mannose and/or glucose terminals were mainly detected in S. dicentrarchi and P. sparis valves. Polar capsule walls were intensively recognised by Con-A in S. dicentrarchi and with medium intensity in P. sparis and Leptotheca sp. The polar filament was scarcely labelled except in Leptotheca sp. with BS-I. The sporoplasms of the studied parasites were stained with all the lectins tested with each myxosporea, except those of Leptotheca sp. with BS-I. Some structures of the developmental stages of Zschokkella mugilis and Leptotheca sp. were stained with BS-I. The possible role of these carbohydrate terminals found in the studied Myxosporea is discussed

Carriage of potentially fish-pathogenic bacteria in Sparus aurata cultured in Mediterranean fish farms

A bacteriological survey of gilthead sea bream Sparus aurata from different fish farms and culture systems on the Spanish Mediterranean coast was conducted. Three different studies were performed. Study A included hatchery-reared larvae; Study B, periodic examination of randomly sampled growing fish; and Study C, growing fish sampled only during mortality/morbidity events. In Studies B and C, sea cages, earth ponds and indoor tanks were surveyed, and in both cases diseased (showing clinical signs) and non-diseased fish were included. In Study A, a shift from Vibrio spp. (30 d after hatching) to oxidative species (60 d after hatching) was detected, and no mortality events were registered. The percentage of fish yielding bacterial growth were similar in Studies B and C, reaching 57.4 and 61.3%, respectively. A statistically significant relationship between the bacterial carriage and the type of facility was only found in Study B, showing that fish from sea cages had a higher bacterial occurrence than fish from other facilities. A statistically significant relationship between bacterial carriage and signs of disease was found, although the pattern differed in each study. Thus, in Study B only 36.2% of fish yielding abundant bacterial growth were diseased, versus 68.0% in Study C. In total, 25.0% of the fish examined were diseased. Bacterial species composition was similar in asymptomatic and diseased fish, except for a group of V. ichthyoenteri-like isolates that occurred almost exclusively in asymptomatic fish. Dominant bacterial species were V. harveyi and V. splendidus, followed by V. ichthyoenteri-like isolates, Photobacterium damselae ssp. damselae and V. fisheri. Non-fermenters were less frequent but, among them, unidentified halophilic Cytophaga-Flavobacterium isolates and Pseudoalteromonas haloplanktis were the most abundant. An association of individual species with disease was not clear, which suggests the involvement of mixed infections.Pujalte Domarco, M Jesus, [email protected] ; Garay Auban, Esperanza, [email protected]