Page 49 - 《渔业研究》2025年第5期

590 渔 业 研 究 第 47 卷

Establishment and evaluation of a co-habitation model for GCRV infection in
Gobiocypris rarus

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YAN Hui ，GAO Wa ，CHEN Kangyong ，FENG Jianhua ，WU Haixia ，
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XU Jing ，XU Zhen ，WANG Junya ，ZOU Jun 1*
(1. College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China;
2. State Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology,
Chinese Academy of Sciences, Wuhan 430072, China)
Abstract: [Background] Grass carp reovirus (GCRV) is the causative agent of hemorrhagic disease in grass
carp (Ctenopharyngodon idella), posing a serious threat to freshwater aquaculture in China. Establishing an in-
fection model that mimics natural transmission is essential for elucidating the epidemiology and pathogeny of
this virus. [Objective] This study aims to develop a co-habitation model of GCRV infection in rare minnow
(Gobiocypris rarus) to investigate its pathogenicity, viral load in tissues, and host immune responses. [Meth-
ods] Rare minnows were infected with GCRV via intraperitoneal injection, and kept in the same tank with an
equal number of healthy fish for up to 3 weeks. Disease progression was monitored, mortality was recorded, and
survival rates were obtained. The expression levels of the viral gene (Vp5) encoding capsid protein and host an-
tiviral gene (Mx1) in the gills, spleen, and hindgut were quantified using quantitative real-time polymerase chain
reaction (qRT-PCR). [Results] In the injection group, mortality was observed on day 4 post-infection, and all
injected fish died on day 8. In contrast, the co-habitation group exhibited a delayed and more prolonged disease
progressing, with mortality recorded on day 12 and reaching 100% on day 20. It was shown that significantly
higher Vp5 expression was detected in the gills compared to the spleen and hindgut under both infection modes.
Additionally, the expression of Mx1 was significantly upregulated in all examined tissues. [Conclusion] A co-
habitation infection model for GCRV was successfully established in rare minnow. The results indicated that
gills serve as a key entry site for viral invasion. Although host antiviral defense is activated upon infection, it is
insufficient to control viral replication. The co-habitation infection model provides a valuable tool for further in-
vestigation into the transmission dynamics, pathogenesis, host immune response to GCRV, and the develop-
ment of control strategies.
Key words: grass carp reovirus (GCRV); grass carp (Ctenopharyngodon idella); rare minnow (Gobiocypris
rarus); co-habitation infection; horizontal transmission