Epidemic Risks associated with high-temperature replicating infectious hematopoietic necrosis virus (IHNV) field isolates: from molecular characterization to host pathogen interactions
- 1INRAE
Abstract
Infectious hematopoietic necrosis virus (IHNV) is a WOAH-notifiable pathogen responsible for severe acute disease in salmonids at temperatures ranging from 4 to 14{degrees}. At higher water temperatures, the disease is generally associated with reduced mortality and lower viral replication. In the context of climate change, rising water temperatures could favor the emergence of thermotolerant strains while representing a major physiological and metabolic stress potentially altering fish's immune responses. This study aims to characterize the impact of increasing water temperatures on IHNV replication and host-pathogen interactions. Following pre-screening, the replication kinetics of the reference strain N61 and two field isolates RtNag0a and SA-22 were characterized in EPC (Epithelioma Papulosum Cyprini) and RTG-2 (Rainbow trout gonad) cell lines at 14, 20 and 22{degrees}. Virulence and host-pathogen interactions were subsequently investigated in vivo in zebrafish (Zf) larvae using complementary microinjection and bath immersion infection models at 21.5 and 23.5{degrees}. In vitro studies revealed distinct thermal replication profiles, distinguishing thermosensitive from thermotolerant isolates, although these phenotypes were influenced by the cellular environment. The zebrafish model enabled the characterization of virulence and antiviral host responses associated with thermotolerant IHNV isolates. Notably, waterborne infection proved effective, contrasting with previous reports describing this exposure route as unsuitable for IHNV studies. These findings expand the growing list of emerging European IHNV genotypes capable of replicating at elevated temperatures (>20{degrees}) and establish zebrafish larvae as a relevant model for virulence assessment of field isolates. Together, these results provide valuable insights into the potential impact of climate warming on IHNV epidemiology and support efforts to predict and anticipate future outbreaks under changing environmental conditions.
Related
- Transcriptional Signatures Associated with Etiology of Post-Hematopoietic Cell Transplant Lung Injury
- Jing Si Herbal Tea Aqueous Extract Modulates G-CSF-Induced Hematopoietic Stem and Progenitor Cells Mobilization and Mitigates Associated Pain in a Murine Model.
- Mosquito population dynamics are shaped by interactions among larval density, temperature, and relative humidity.
- The impact of contamination bias when replicating maltreatment effects on child behavior problems
- Characterization of 3D heterocellular spheroids of pancreatic ductal adenocarcinoma for the study of cell interactions in the tumor immune microenvironment
BibTeX
@misc{gourhannic2026epidemic,
title = {{Epidemic Risks associated with high-temperature replicating infectious hematopoietic necrosis virus (IHNV) field isolates: from molecular characterization to host pathogen interactions}},
author = {E. Gourhannic and C. Fauvet and M. Mehraz and P. Pondaven and M. Aurousseau and M. Fretaud and S. Biacchesi and J. K. Millet and L. Louboutin and G. Lannuzel and Y. Blanchard and M.-L. Tran and P. Fach and D. Rigaudeau and T. Morin and C. langevin},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.29.762392},
url = {https://www.biorxiv.org/content/10.64898/2026.10.29.762392v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Epidemic Risks associated with high-temperature replicating infectious hematopoietic necrosis virus (IHNV) field isolates: from molecular characterization to host pathogen interactions
AU - E. Gourhannic
AU - C. Fauvet
AU - M. Mehraz
AU - P. Pondaven
AU - M. Aurousseau
AU - M. Fretaud
AU - S. Biacchesi
AU - J. K. Millet
AU - L. Louboutin
AU - G. Lannuzel
AU - Y. Blanchard
AU - M.-L. Tran
AU - P. Fach
AU - D. Rigaudeau
AU - T. Morin
AU - C. langevin
PY - 2026
DA - 2026/10/29
PB - bioRxiv
DO - 10.64898/2026.10.29.762392
UR - https://www.biorxiv.org/content/10.64898/2026.10.29.762392v1
AB - Infectious hematopoietic necrosis virus (IHNV) is a WOAH-notifiable pathogen responsible for severe acute disease in salmonids at temperatures ranging from 4 to 14{degrees}. At higher water temperatures, the disease is generally associated with reduced mortality and lower viral replication. In the context of climate change, rising water temperatures could favor the emergence of thermotolerant strains while representing a major physiological and metabolic stress potentially altering fish's immune responses. This study aims to characterize the impact of increasing water temperatures on IHNV replication and host-pathogen interactions. Following pre-screening, the replication kinetics of the reference strain N61 and two field isolates RtNag0a and SA-22 were characterized in EPC (Epithelioma Papulosum Cyprini) and RTG-2 (Rainbow trout gonad) cell lines at 14, 20 and 22{degrees}. Virulence and host-pathogen interactions were subsequently investigated in vivo in zebrafish (Zf) larvae using complementary microinjection and bath immersion infection models at 21.5 and 23.5{degrees}. In vitro studies revealed distinct thermal replication profiles, distinguishing thermosensitive from thermotolerant isolates, although these phenotypes were influenced by the cellular environment. The zebrafish model enabled the characterization of virulence and antiviral host responses associated with thermotolerant IHNV isolates. Notably, waterborne infection proved effective, contrasting with previous reports describing this exposure route as unsuitable for IHNV studies. These findings expand the growing list of emerging European IHNV genotypes capable of replicating at elevated temperatures (>20{degrees}) and establish zebrafish larvae as a relevant model for virulence assessment of field isolates. Together, these results provide valuable insights into the potential impact of climate warming on IHNV epidemiology and support efforts to predict and anticipate future outbreaks under changing environmental conditions.
ER -