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| Epidemic Characteristics of Different Species of Aeromonas in Diseased Fish in Southern China |
| ZHANG Defeng,LIU Lihui,LI Ningqiu,REN Yan,LIN Qiang,SHI Cunbin,WU Shuqin |
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Abstract In this study ,143 bacterial strains were isolated from 15 species of diseased fishes including grasscarp(Ctenopharyngodonidellus),silvercarp(Hypophthalmichthysmolitrix),bigheadcarp(Aris‐tichthys nobilis) ,crucian carp (Carassius auratus) ,mandarin fish (Siniperca chuatsi) ,channel catfish (Ictalurus punctatus) ,snakehead (Channa argus) and red drum (Sciaenops ocellatus) in 70 ponds in southern China ,and identified by physiological and biochemical analysis ,and phylogenetic analysis .Phy‐logenetic tree of the bacterial strains was constructed by sequencing of the gyr B and rpo D genes .The re‐sults showed that the 80 isolates were identified as Aeromonas veronii ,40 isolates as A .hydrophila ,9 i‐solates as A . j andaei ,10 isolates as A .schubertii and 4 isolates as A .aquariorum ,indicating that A ero‐monas spp .as the pathogens of fish in southern China had diversity ,A .veronii (80/143 ,56% ) as primary species of Aeromonas infecting grass carp ,silver carp and mandarin fish .A .hydrophila (40/143 ,28% ) was found in bighead carp ,black bream (Megalobrama amblycephala) and channel catfish .In addition , the A . j andaei (9/143 ,6% ) had hosts of grass carp ,bighead carp ,black bream and koi carp (Cy p rinus carpi) ,but A .schubertii (10/143 ,7% ) had the host only the snakehead .To the best of our knowledge , the A .aquariorum was only found in diseased red drum in China .The findings indicated that A .veronii and A .hydrophila were the primary pathogens of motile aeromonad septicaemia in fish and the mixed in‐fections were often occurred due to the two species ,which will provide a rational framework for explora‐tion of epidemiological analysis ,prevention and treatment of the A eromonas spp .in fish diseases .
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Received: 25 November 2015
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