Intensive aquaculture production systems often encounter infectious viral disease outbreaks causing substantial fish mortalities and associated economic losses. Blue catfish alloherpesvirus (BCAHV) is an Ictalurid herpesvirus with limited information on pathogenesis. To determine the host-specificity and potential host range of BCAHV, the virus was inoculated onto various fish cell lines belonging to families Ictaluridae, Cyprinidae, Centrarchidae, and Clariidae. Viral replication and exhibition of cytopathic effects (CPEs) were restricted to cell lines from the family Ictaluridae indicating the host preference of BCAHV. Subsequently, fish challenges were conducted to evaluate intrinsic and extrinsic factors influencing BCAHV infection. Mortality because of BCAHV infection was significantly higher in blue catfish and least in channel catfish further specifying the host preference of the virus. Histopathological assessment of the BCAHV infected fish revealed splenitis with severe erythrophagia. Host susceptibility to BCAHV differed with age with fish at 60 days post hatch being more susceptible. Temperature had a significant role in the activation and pathogenesis of BCAHV. Fish exposed to BCAHV at a sustained high temperature had significantly low mortality suggesting the likelihood of virus inactivation. Virus exposure in tanks with high stocking density resulted in significantly high fish mortalities indicating horizontal transmission is a key element in BCAHV pathogenesis. The heightened pathogenicity of BCAHV in blue and hybrid catfish as observed in this study validates its potential to be a significant pathogen in catfish production.
Bibliographical noteFunding Information:
The cell culture viable BCAHV stock (S98‐675) was provided by Dr. Larry Hanson, College of Veterinary Medicine, Mississippi State University. The authors thank David Wise, Divya Johnson, Marsha Lewis, Todd Byars, Rodney Morris, and Monroe Walker for their technical assistance. This study was supported by the Mississippi Agricultural and Forestry Experiment Station (MAFES) Strategic Research Initiative (CRIS project #MIS‐371932), United States Department of Agriculture—Agricultural Research Service—Catfish Health Initiative (CRIS 6402‐31320‐002‐02), and the Delta Research and Extension Center, Stoneville, MS. The research findings documented in the publication are those of the author(s) and do not reflect the view of the United States Department of Agriculture.
© 2021 The Authors. Journal of the World Aquaculture Society published by Wiley Periodicals LLC on behalf of World Aquaculture Society.
- blue catfish alloherpesvirus
- host preference
- hybrid catfish