RESUMO
A Piscirickettsia salmonis infection was diagnosed in lumpfish (Cyclopterus lumpus L.) juveniles held in a marine research facility on the west coast of Ireland. The main clinical signs and pathology included marked ascites, severe multifocal liver necrosis and severe diffuse inflammation and necrosis of the exocrine pancreas and peri-pancreatic adipose tissue. Numerous Piscirickettsia-like organisms were observed by histopathology in the affected organs, and the bacterial species was characterized by molecular analysis. Sequencing of the partial 16S rDNA gene and internal transcribed spacer region showed the lumpfish sequences to be closely related to previously identified Atlantic salmon (Salmo salar L.) sequences from Ireland. To the authors' knowledge, this is the first detection of P. salmonis in lumpfish worldwide. The infection is considered potentially significant in terms of lumpfish health and biosecurity.
Assuntos
Doenças dos Peixes/patologia , Peixes , Piscirickettsia/isolamento & purificação , Infecções por Piscirickettsiaceae/veterinária , Animais , Aquicultura , Sequência de Bases , DNA Intergênico/genética , Doenças dos Peixes/microbiologia , Irlanda , Filogenia , Piscirickettsia/classificação , Piscirickettsia/genética , Infecções por Piscirickettsiaceae/microbiologia , Infecções por Piscirickettsiaceae/patologiaRESUMO
Infectious gill diseases of marine salmonid fish present a significant challenge in salmon-farming regions. Infectious syndromes or disease conditions affecting marine-farmed salmonids include amoebic gill disease (AGD), proliferative gill inflammation (PGI) and tenacibaculosis. Pathogens involved include parasites, such as Neoparamoeba perurans, bacteria, such as Piscichlamydia salmonis and Tenacibaculum maritimum, and viruses, such as the Atlantic salmon paramyxovirus (ASPV). The present level of understanding of these is reviewed with regard to risk factors, potential impacting factors, methods of best practice to mitigate infectious gill disease, as well as knowledge gaps and avenues for future research.
Assuntos
Doenças Transmissíveis/veterinária , Doenças dos Peixes/microbiologia , Doenças dos Peixes/parasitologia , Salmão , Animais , Doenças Transmissíveis/microbiologia , Doenças Transmissíveis/parasitologia , Doenças dos Peixes/imunologia , Doenças dos Peixes/patologia , Brânquias/imunologia , Brânquias/microbiologia , Brânquias/parasitologia , Brânquias/patologia , Prevalência , Fatores de RiscoRESUMO
Intracellular inclusions containing chlamydia-like organisms are frequently observed in the gill epithelial cells of Atlantic salmon, Salmo salar L., cultured in fresh water in Ireland. In this study, the causative agent was identified in four separate freshwater sites, using 16s rRNA sequencing, as 'Candidatus Clavochlamydia salmonicola'. Histopathology and real-time (RT) PCR were used to further assess infections. The prevalence of infection ranged from 75-100% between sites and infection intensity was highly variable. No significant lesions were associated with these infections. As a diagnostic tool, RT-PCR proved marginally more sensitive than histopathology. The fate of 'Candidatus Clavochlamydia salmonicola' in Atlantic salmon post-seawater transfer was investigated in a 12-week marine longitudinal study. Both RT-PCR and histopathological examination indicate that the organism disappears from the gills 4-6 weeks post-transfer.
Assuntos
Infecções por Chlamydiaceae/veterinária , Chlamydiaceae/fisiologia , Doenças dos Peixes/microbiologia , Água Doce , Salmo salar , Animais , Chlamydiaceae/genética , Infecções por Chlamydiaceae/epidemiologia , Infecções por Chlamydiaceae/microbiologia , Infecções por Chlamydiaceae/patologia , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/patologia , Pesqueiros , Brânquias/microbiologia , Brânquias/patologia , Irlanda/epidemiologia , Dados de Sequência Molecular , Prevalência , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Água do Mar , Fatores de TempoRESUMO
A study of four marine salmon farms was undertaken in Ireland in 2008, with a focus on gill health and disease. All four farms suffered severe gill disease resulting in mortalities and, in some cases, failure to thrive. The aetiology of the gill pathologies in some cases was associated with small gelatinous zooplankton and bacteria, but also involved epitheliocystis and parasites such as marine costia (Ichthyobodo species) and amoebae (Neoparamoeba species). Treatments with oral broad-spectrum antibiotics and/or freshwater baths had equivocal benefits. There was a strong association of susceptibility to gill disease with one genetic strain of salmon.