Pathological changes in cultured channel catfish Ictalurus punctatus spontaneously infected with Streptococcus iniae

Abstract

ABSTRACT:The pathological changes present in channel catfish Ictalurus punctatus spontaneously infected by Streptococcus iniae are described. The most consistent gross findings were marked petechial hemorrhages of the skin and congestion of internal organs, particularly the liver, spleen and kidneys. Other features included color fading at the edge of fin rays, enteritis and ascites. Histological examination showed oedema, degeneration and necrotic changes in many organs. Further, hepatitis, splenitis, interstitial nephritis, and meningitis with numerous monocyte and neutrocyte infiltrates were evident. Intact S. iniae cells were seen in macrophages. Apparently, spontaneous S. iniae infection caused acute septicaemia in channel catfish. This is the first histopathological report on channel catfish naturally infected with S. iniae. KEY WORDS: Histopathology · Channel catfish · Streptococcus iniaeResale or republication not permitted without written consent of the publisher

Establishment of a striped catfish skin explant model for studying the skin response in Aeromonas hydrophila infections

“…Because previous studies reported that lesions of ventral skin region are common in various pathogen infections in catfish 31 – 33 , we used the ventral skin model to determine if it could be used as an infection model. We inoculated AH into the apical side of the ventral skin model for 6 h and investigated tissue integrity and the barrier function compared to no bacteria control.…”

Characterization and expression analysis of chitinase genes (CHIT1, CHIT2 and CHIT3) in turbot (Scophthalmus maximus L.) following bacterial challenge

“…Especially, in Lates calcarifer, bath exposure of S. iniae could resulted in higher level of mortality within the first 48 h, which is much more significant than oral exposure [42]. In addition, the pathogenic characteristic of S. iniae infection was marked petechial hemorrhages of the skin [43].…”

Isolation and Genetic Characterization of Streptococcus iniae Virulence Factors in Adriatic Sturgeon (Acipenser naccarii)

“…Streptococcus iniae has been reported as one of the most important pathogenic bacteria in aquaculture resulting in severe economic losses of hundreds of millions of dollars annually [ 1 ]. S. iniae is the main causative agent of streptococcosis in wild and farmed fish worldwide, affecting at least 27 different species, including rainbow trout ( Oncorhynchus mykiss ) [ 2 , 3 , 4 ], Nile tilapia ( Oreochromis niloticus ) [ 5 , 6 ] and its hybrids [ 7 ], Siberian sturgeon ( Acipenser baerii ) [ 8 , 9 ], channel catfish ( Ictalurus punctatus ) [ 10 ], barramundi ( Lates calcarifer ) [ 11 , 12 ], red drum ( Sciaenops ocellatus ) [ 13 ] and Japanese flounder ( Paralichthys olivaceus ) [ 14 , 15 ]. Moreover, S. iniae represents a zoonotic risk, usually associated with the handling and preparation of infected fish for consumption [ 16 ].…”