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Intragastric and intracoelomic injection challenge models of tilapia lake virus infection in Nile tilapia ( Oreochromis niloticus L.) fingerlings
Author(s) -
Pierezan Felipe,
Yun Susan,
Surachetpong Win,
Soto Esteban
Publication year - 2019
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.13052
Subject(s) - oreochromis , nile tilapia , biology , tilapia , gill , pathogenesis , intraperitoneal injection , veterinary medicine , virology , fish <actinopterygii> , immunology , medicine , fishery , endocrinology
To gain a better understanding of the pathogenesis of tilapia lake virus (TiLV) infections in Nile tilapia ( Oreochromis niloticus ), fingerlings were challenged with a single dose of 1 × 10 4 TCID 50 /fish of TiLV utilizing intracoelomic/intraperitoneal (IC ch ) or intragastric (IG ch ) routes. Acute mortalities were present in both groups, reaching 70 and 40% in IC ch and IG ch after 10 days, respectively. Challenged fish presented erratic swimming, lethargy, anorexia, exophthalmia and cutaneous petechiae and ecchymoses. Histological changes in challenged groups included syncytial formation, intracytoplasmic inclusion bodies and multifocal hepatocellular degeneration and necrosis. In addition, multifocal areas of mild proliferation of glial cells and lymphocytic perivascular cuffing were observed in the brain of exposed challenged groups. TiLV RNA was detected in gills and faeces of challenged fish using quantitative reverse transcriptase–PCR, as well as in the tank water holding challenged fish. Moreover, TiLV RNA was detected in scrolls obtained from formalin‐fixed paraffin‐embedded tissue blocks from challenged fish. Results from this study suggest that IG methods represent an additional method to study the pathogenesis of the disease in this species, as it results in infection and diseases as in naturally occurring cases and does not bypass important mucosal immune responses as injectable routes do.