Επιζωοτιολογική μελέτη και πρόληψη των σημαντικότερων βακτηριακών και ιογενών νοσημάτων των εκτρεφόμενων μεσογειακών ιχθυών της Ελλάδας

Abstract

Epizootiological survey was performed with emphasis on pathogen agents and their geographic distribution of the most severe bacterial and viral diseases: vibriosis, photobacteriosis, tenacibaculosis, furunculosis and motile aeromonas septicemia, and viral nervous necrosis. Σhe most important cultured Mediterranean finfish species, European sea bass, gilthead sea bream, sharpsnout sea bream, red porgy, white sea bream, were studied. Eleven aquaculture case locations and the causal pathogens maps were designed with Geographical Information System (GIS) ARC-MAP program. These maps included the Greek coast-line and Argolicos, Argosaronicos – Saronicos, Corinthiacos gulf, Miticas Aitoloacarnania coast, Ionian Sea Island coasts, river Louros delta, Central, East and West Amvrakikos gulf, Igoumenitsa and Sagiada coasts, Maliacos gulf, Atalanti Phthiotis coast and North Evoicos gulf, Porto Lagos lagoon rearing locations. The time period of this survey was 1998 – 2014. For European sea bass, 178 outbreaks were recorded for: a) vibriosis (100), caused from Listonella anguillarum (12 – 260C), in most of Greek rearing locations,from Vibrio harveyi (19 – 220C), V. alginolyticus and V. splendidus II (160C), especially in Argolikos gulf, North Evoic gulf and Ionian Island coasts, and from non-specific Vibrio spp. (4), b) photobacteriosis (34) caused from Photobacterium damselae subspecies piscicida (19–250C) in the majority of Greek rearing locations and Photobacterium damselae subspecies damselae (19–24.50C), mainly in the above three locations, c) tenacibaculosis (7) from Tenacibaculum maritimum (220C), in the above three locations, and, at 180C, in Portos Lagos lagoon, d) motile aeromonas septicemia (MAS) from Aeromonas sp. (7), A. sobria (3) at 220C, in three locations, and A. hydrophila (7), 2 outbreaks at 150C, and 1 outbreak at 210C, in Saronicos – Corinthiacos and Saronicos – Argosaronicos gulf, and 4 cases, at 280C, in river Louros delta of West Greece e) viralnervous necrosis (16) from Beta-nodavirus RGNNV genotype, in river Louros delta and Ionian Sea Island coasts, at too high temperature values (25–280C). Acute form of classical vibriosis and photobacteriosis were diagnosed in sea bass larvae and juveniles or fingerlings with an average body weight up to 80 g, immature specific immunity and chronic or asymptomatic form in young and adult fish with an average body weight over 80 g, mature specific immunity. For gilthead sea bream, 76 outbreaks were recorded for: a) photobacteriosis, caused from Photobacterium damselae subspecies damselae (18) at high (21–24,50C) and P. damselae subspecies piscicida (16) mostly at high (220C) temperature values, b) classic vibriosis (7) from Listonella anguillarum with an even distribution at high (22 – 250C) and low (17 0C) temperature values, rest vibria vibriosis caused from Vibrio alginolyticus (6 cases) at low (160C), V. harveyi (5) at high (220C), V. splendidus II (6) at medium (200C), V. vulnificus biotype (6) at high (220C) temperature values, in Argolikos gulf, North Evoic gulf and Ionian Island coasts, and from non-specific Vibrio spp. (2), c) tenacibaculosis (3) from Tenacibaculum maritimum at 18,50C and at 180C, in Maliacos gulf and Porto Lagos lagoon, d) motile aeromonas septicemia (MAS) from Aeromonas sobria (3) and unclassified Aeromonas sp.(4), mainly at high temperature values (21 – 280C), in Argolikos gulf, North Evoic gulf and Ionian Island coasts and Porto Lagos lagoon. For sharpsnout sea bream, 26 outbreaks were recorded for: a) vibriosis, caused from Vibrio alginolyticus (6) at medium temperature (210C), from V. harveyi (4) at 180C, Listonella anguillarum (3) at medium (200C), V. splendidus II (3) low (170C), V. parahaemolyticus (3) medium (210C) temperature values, b) photobacteriosis from Photobacterium damselae subspecies damselae (3) at high temperature (220C), c) motile aeromonas septicemia (MAS) from Aeromonas caviae (3), at 210C, in Argolikos gulf, North Evoic gulf and Ionian Island coasts and from A. hydrophila at 150C, in Corinthiacos. For red porgy and white sea bream sporadic vibriosis cases (5 and 9, corresponsively) were recorded at low (16–170C) and medium (19–200C) temperature values, in the above three locations. Diagrams were plotted for case number pie distribution for every above disease pathogen agent in Greece coastline and for the statistically examined fish species: European sea bass, gilthead sea bream, sharpsnout sea bream. Two GIS epizootiological maps were constructed, based on the abiotic risk factors of temperature (1st map) and salinity (2nd map) values zone shape files, pilotically for Argosaronicos – Saronicos gulf, for the motile aeromonas septicemia outbreak from Aeromonas hydrophila in sea bass young fish, in October 2008. Their target was the utilization of temperature values zonal raster files from a meteorological data base for the biosecurity program environmental prevention approach. From the initial 294 case database of this survey, through Principal Component Analysis (PCA), the temperature and seasonality value risk factors were dominated. The pathogen-case location areas and fish average body weights risk factors followed in ranking along with the negligible outbreak year factor. By Logistic Analysis, vibriosis and photobacteriosis pathogens prevailed and motile aeromonas septicemia and tenacibaculosis pathogens, secondly, emerged for European sea bass (134 + 18), gilthead sea bream (64 + 9) and sharpsnout sea bream (22 + 3) in the statistical baseof 250 bacterial diseases cases. Moreover, through Contrast Assay, temperature and seasonality were found as the most statistically significant risk factors for sea bass vibriosis and hotobacteriosis epizootiology. The survey resulted in a proposal for a biosecurity program grounded on pathogenlocal adversive temperature value range and seasonal conditions of environemental and sanitary integrated preventive approach.