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Yoon SY, Jang YS, Kim SJ, Krishnan R, Oh MJ. Determination of the minimum infective dose of viral hemorrhagic septicemia virus (VHSV) in juvenile olive flounder, Paralichthys olivaceus using an immersion challenge model. Virus Res 2024; 340:199305. [PMID: 38158128 PMCID: PMC10792560 DOI: 10.1016/j.virusres.2023.199305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Viral hemorrhagic septicemia virus (VHSV) affects over 80 fish species, leading to viral hemorrhagic septicemia (VHS). Horizontal VHSV transmission is widely studied, with researchers utilizing various doses to establish infection models. Infected hosts shed the virus into the environment, elevating the risk of transmission to naïve fish within the same system. This study aimed to ascertain the minimum infective dose of VHSV in olive flounder (Paralichthys olivaceus). In olive flounder, the detection of VHSV within the kidney exhibited the highest infection rate on the third day among days 1, 3 and 5. Doses of 103.0 to 104.7 TCID50/ml were administered to juvenile olive flounder across three farms. Results showed resistance to infection below 103.4 TCID50/ml at 15 °C. While infection frequency varied by concentration, higher concentrations correlated with more infections. Nonetheless, viral copy numbers did not differ significantly among infected fish at varying concentrations. This study underscores the need for early VHSV management and contributes essential data for pathogenicity assessment and foundational knowledge.
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Affiliation(s)
- Su-Young Yoon
- Department of Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea
| | - Yo-Seb Jang
- Department of Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea
| | - Soo-Jin Kim
- Department of Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea; Pathology Division, National Institute of Fisheries Science (NIFS), Busan, Republic of Korea
| | - Rahul Krishnan
- Department of Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea; Department of Aquatic Animal Health Management, Faculty of Fisheries, Kerala University of Fisheries and Ocean Studies, Kerala, India
| | - Myung-Joo Oh
- Department of Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea.
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Li J, Xia D, Zhang M, Zhang Y, Liu X, Sun J, Xu B, Yang J, Wang N, Shi W, Guan X, Liu M. Infectious hematopoietic necrosis virus (IHNV) nucleoprotein amino acid residues affect viral virulence and immunogenicity in rainbow trout (Oncorhynchus mykiss). FISH & SHELLFISH IMMUNOLOGY 2022; 130:572-581. [PMID: 35988711 DOI: 10.1016/j.fsi.2022.08.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/10/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
This study compared the N protein sequences of genotype J with other genotypes of IHNV to select amino acid residues that may be related to the change in viral virulence. The recombinant viruses containing different mutation sites were rescued by alanine scanning mutagenesis and the reverse genetic system. The nine recombinant virus strains obtained in this work were named rIHNV-N85, rIHNV-N102, rIHNV-N146, rIHNV-N380, rIHNV-N85-102-146, rIHNV-N85-102-380, rIHNV-N85-146-380, rIHNV-N102-146-380, and rIHNV-N85-102-146-380. Pathogenicity and immunity assays were performed to determine the role of virulence sites. The result of the pathogenicity test showed that the survival rates of rIHNV-N85, rIHNV-N102, rIHNV-N85-102-146, and rIHNV-N85-102-380 groups were 52.5%, 55%, 67.5%, and 57.5%, while the survival rate of wild-type (wt) IHNV HLJ-09 group was only 10%. The replication ability of recombinant viruses with substitutions at positions 85 and 102 was significantly inhibited in vivo and in vitro. The qRT-PCR result indicated that the cytokines of IFN1, IL-8, and IL-1β expression levels were increased in rIHNV-N85, rIHNV-N102, rIHNV-N85-102-146, and rIHNV-N85-102-380 groups. In addition, these four recombinant viruses could cause the rainbow trout to produce anti-IHNV-specific antibodies immunoglobulin M (IgM) earlier, confirming that 85 and 102 amino acid residues of N protein affected the virulence and immunogenicity of IHNV. All these results suggest that mutations of the N protein virulence sites reduce virulence while retaining immunogenicity. This also provides a new idea for studying the virulence mechanism of rhabdoviruses and preparing attenuated vaccines.
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Affiliation(s)
- Jiahui Li
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Dong Xia
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Mengmeng Zhang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Yanru Zhang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Xuefei Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Jinhui Sun
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Baoxing Xu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Jiawei Yang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Na Wang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Wen Shi
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Xueting Guan
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Guangdong Ocean University, Zhanjiang, 524025, People's Republic of China.
| | - Min Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
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Early or Simultaneous Infection with Infectious Pancreatic Necrosis Virus Inhibits Infectious Hematopoietic Necrosis Virus Replication and Induces a Stronger Antiviral Response during Co-infection in Rainbow Trout ( Oncorhynchus mykiss). Viruses 2022; 14:v14081732. [PMID: 36016354 PMCID: PMC9414607 DOI: 10.3390/v14081732] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/26/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
Infectious hematopoietic necrosis (IHN) and infectious pancreatic necrosis (IPN) are the most common viral diseases of salmon in aquaculture worldwide. The co-infection of rainbow trout (Oncorhynchus mykiss) with IHN virus (IHNV) and IPN virus (IPNV) is known to occur. To determine the influence of IPNV on IHNV in co-infection, rainbow trout were intraperitoneally (i.p.) injected with IPNV at different time intervals prior to, simultaneously to, or after IHNV infection. The replication of IHNV in the brain, gill, heart, liver, spleen, and head kidney was detected by real-time quantitative polymerase chain reaction (qRT-PCR). The results showed that when rainbow trout were i.p. injected with IPNV prior to, simultaneously to, or after IHNV on 2 day (d), IHNV replication was inhibited (p < 0.05) in all collected tissues. Nevertheless, when rainbow trout were i.p. injected with IPNV after IHNV on 7 d (H7P), IHNV replication was only inhibited (p < 0.05) in the liver 14 d post-IHNV infection. Moreover, stronger antiviral responses occurred in all challenge groups. Our results suggest that IPNV can inhibit IHNV replication before or simultaneously with IHNV infection, and induce a stronger antiviral response, and that this inhibition is most sensitive in the liver. Early i.p. injection of IPNV can significantly reduce the mortality of rainbow trout, compared with the group only injected with IHNV.
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