title: Outbreak of infectious pancreatic necrosis virus (IPNV) in farmed rainbow trout in China.
abstract: Infectious pancreatic necrosis virus (IPNV) is a member of the Aquabirnavirus genus, which caused mass mortality (nearly 100%) in farmed rainbow trout (Oncorhynchus mykiss) in aquaculture farms in 2016, China. Major clinical signs included decreased appetite, mucous-like stools, and darkened pigmentation. Pathological changes in moribund fish were observed, such as marked vacuolar degeneration of the pancreatic cells with pyknotic nucleus and decreased zymogen granules, severe hemorrhage in the liver, and tumidness of respiratory epithelium in gills. In addition, the tissue fluid of diseased fish could produce a cytopathic effect (CPE) in RTG-2 cells. The presence of specific 206bp fragments by the reverse transcription-polymerase chain reaction (RT-PCR) using tissue homogenate of diseased fish and supernatant of infected cells revealed that IPNV could be confirmed. The pathogenicity test of cell culture supernatant detected cumulative mortality of 80%, and the clinical symptoms observed in the moribund and dead fish were similar to the naturally infected fish. Furthermore, the sequence analysis of VP2 gene showed that the isolated virus strain belonged to genogroup 1, and 97% homology with the Mexican IPNV isolate was found. To our knowledge, this is the first report on IPNV natural infection in the southwest of China.
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Xingli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, Sichuan, China. Electronic address: kywang1955@126.com.
authors.forename: Kaiyu
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Jie
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Zhenyang
authors.initials: Z
authors.lastname: Qin
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Geng
authors.affiliation: Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Ouyang
authors.affiliation: Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Huang
mesh_terms: D000818:Animals; D017756:Aquaculture; D018175:Birnaviridae Infections / Q000453:epidemiology* / Q000821:virology; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D005393:Fish Diseases / Q000453:epidemiology*; D018061:Infectious pancreatic necrosis virus / Q000302:isolation & purification*; D017686:Oncorhynchus mykiss / Q000821:virology*
keywords: China; Histopathology; IPNV; Infectious pancreatic necrosis; Rainbow trout