title: The pathology associated with visceral toxicosis of catfish.
abstract: Visceral toxicosis of catfish (VTC) syndrome was recognized in the late 1990 s and recently has been associated with exposure to Clostridium botulinum type E neurotoxin. Tentative diagnosis is based on clinical presentation and gross findings, and is confirmed by bioassay. In April 2009, channel catfish (Ictalurus punctatus) from 2 different farms presented with abnormal swimming behavior and mortalities. Nine fish were submitted to the Aquatic Research and Diagnostic Laboratory (Stoneville, Mississippi) for evaluation. Bacterial cultures from these fish were negative. Necropsy findings included intestinal intussusceptions, ascites, pale proximal intestines with engorged serosal blood vessels, splenic congestion, and a reticular pattern to the liver. Significant histopathologic findings were limited to cerebral, splenic, and hepatic congestion, splenic lymphoid depletion and perivascular edema, vascular dilation and edema of the gastrointestinal tract, and perivascular edema in the anterior and posterior kidneys. Intoxication from C. botulinum type E neurotoxin was suspected based on the clinical signs and lack of gross and microbiological evidence of an infectious disease process. The toxicosis was confirmed with a positive bioassay using serum collected from the submitted fish.
authors.affiliation: Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, PO Box 197, Stoneville, MS 38776, USA. Khoo@cvm.msstate.edu
authors.forename: Lester H
authors.initials: LH
authors.lastname: Khoo
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Goodwin
authors.forename: David J
authors.initials: DJ
authors.lastname: Wise
authors.forename: William E
authors.initials: WE
authors.lastname: Holmes
authors.forename: Larry A
authors.initials: LA
authors.lastname: Hanson
authors.forename: James M
authors.initials: JM
authors.lastname: Steadman
authors.forename: Larry M
authors.initials: LM
authors.lastname: McIntyre
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Gaunt
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000302:isolation & purification; D001906:Botulism / Q000473:pathology / Q000662:veterinary*; D005393:Fish Diseases / Q000382:microbiology / Q000473:pathology*; D005767:Gastrointestinal Diseases / Q000662:veterinary*; D007059:Ictaluridae
chemical_list: D001905:Botulinum Toxins; C096326:botulinum toxin type E