Singapore grouper iridovirus (SGIV) is one of the major pathogens that pose significant threats to the aquaculture industry. Kaempferol is a flavonoid compound extracted from Illicium verum Hook.f. (star anise), a material that is both edible and used in traditional medicine. In this study, we evaluated the antiviral effects of kaempferol against SGIV in vitro and in vivo, and elucidated the antiviral mechanism. Our study foun...

Singapore grouper iridovirus (SGIV) is a major viral pathogen threatening grouper aquaculture. The lack of specific antiviral drugs underscores the urgent need to develop safe and effective control strategies. This study demonstrates that tannic acid (TA) exhibits significant anti‐SGIV activity in vitro. In grouper spleen (GS) cells, TA inhibited SGIV replication in a concentration‐dependent manner. Time‐of‐addition assays con...

Largemouth bass virus (LMBV), a member of the Ranavirus genus within the Iridoviridae family, is a significant pathogen causing high mortality and substantial economic losses in largemouth bass aquaculture. Therefore, developing effective antiviral agents against this viral infection is crucial for the largemouth bass aquaculture industry. Quercetin, a widely utilised flavonoid known for its therapeutic and prophylactic proper...

Singapore grouper iridovirus (SGIV) is a highly pathogenic virus that causes substantial economic losses in marine grouper aquaculture, and effective antiviral agents are currently lacking. In this study, the anti‐SGIV activity of epigallocatechin gallate (EGCG), a natural compound from green tea, was evaluated and its underlying mechanisms were investigated. Cytotoxicity assays showed that EGCG at concentrations up to 12.5 μg...

In March 2024, a severe mass mortality event occurred at a grass carp ( Ctenopharyngodon idella ) farm in Zhejiang, China, resulting in a cumulative mortality rate of 70%. To identify the causative agent, 12 bacterial isolates that exhibited the same phenotypic characteristics were isolated from diseased fish. A further phylogenetic (16S rDNA) characterization identified the bacterium as Flavobacterium psychrophilum . Genetic...

Largemouth bass ( Micropterus salmoides ) is an important freshwater‐cultured species in China. M. salmoides rhabdovirus (MSRV) is a devastating pathogen that causes high mortality (exceeding 90% in acute outbreaks) in largemouth bass fry, posing a severe threat to the global largemouth bass aquaculture industry. To address the urgent demand for rapid, on‐site MSRV detection, two multienzyme isothermal rapid amplification (MIR...

Vibrio infections cause enteritis in grouper fish, leading to high mortality and stunted growth, which is a major challenge for aquaculture. Oligochitosans, marine prebiotics with bioactive properties, have proven their potential for growth promotion and immune regulation. However, the impacts of Vibrio harveyi on the gut microbiome of grouper fish and the potential of oligochitosans to modulate these effects remain poorly und...

Lymphocystis disease virus (LCDV) stands as one of the most widespread causative agents affecting a diverse array of teleost globally. According to the literature, LCDV encompasses four species, and Lymphocystivirus paralichthys1 (known as LCDV‐C) has long been regarded as the predominant national epidemic isolate in mainland China. In this study, two instances of severe mass mortalities associated with LCDV in brackish‐water...

The phosphoinositide‐3‐kinase/protein kinase b (PI3K‐Akt) pathway is a signalling pathway based on protein phosphorylation and can be activated by a wide range of factors. To investigate the function of the PI3K‐AKT signalling pathway in antibacterial immunity, we analysed the gene expression level of three key factors ( PI3K , AKT and FoxO ) and innate immune factors in immune tissues at different time points after Vibrio par...

Currently, aquaculture is a relatively mature industry; however, disease problems are continuously threatening the industry and hindering its development to a certain extent. Klebsiella pneumoniae is one of the zoonotic bacteria widely present in different hosts and has caused some degree of harm to the aquaculture industry, posing a potential threat to the water environment and indirectly also affecting human food safety issu...

Nervous necrosis virus (NNV) is one of the most destructive pathogens in marine fish aquaculture and is capable of infecting more than 50 fish species worldwide, which resulted in great economic losses. Effective drugs for managing NNV infection are urgently required. Medicinal plants have been known for thousands of years and benefit of medicinal plants against pathogens in aquaculture have emerged. Nowadays, the most commonl...

In this research, Vibrio vulnificus formalin‐killed (FKCs) vaccine and ghost (VVGs) vaccine were successfully developed, and shown to prevent vibriosis of Scophthalmus maximus resulting from V. vulnificus. The antibody titre of FKCs and VVGs vaccine was 1: 2 8 and 1: 2 11 . The RPS of FKCs and VVGs vaccine was 60% and 80%. In order to improve the understanding of vaccine protection mechanism, transcriptome data was used to ana...

Streptococcus agalactiae , also known as Group B Streptococcus (GBS), can infect humans, terrestrial animals and fish. The emergence of bacterial resistance of S. agalactiae to antibiotics leads to an urgent need of exploration of new antimicrobial agents. In the study, the antibacterial activity of natural component plumbagin (PLB) against S. agalactiae was investigated in vitro and in vivo. The results showed that the minima...

Aeromonas schubertii is a major epidemiological agent that threatens cultured snakeheads ( Channidae ) and has caused great economic losses in fish‐farming industries in China in recent years. In present study, a specific TaqMan minor groove binder ( MGB ) probe fluorescence real‐time quantitative PCR ( qPCR ) assay was developed to rapidly detect and quantify A. schubertii . A pair of qPCR primers and a TaqMan MGB probe were...

A disease with white spots in internal organs of Nile tilapia occurred in Zhanjiang, southern China. Multiple, white nodules, 0.8–2.2 mm in diameter, were scattered throughout the liver, spleen and kidney of diseased fish. Signs of nodules reproduced after artificial infection with the isolated strain. Isolated bacteria were Gram‐negative, facultative anaerobic, motile, short rod‐shaped, with a length of 1.2–2.2 μm. Morphologi...

To develop an effective and easy‐to‐administer vaccine against vibriosis of fish, the chitosan nanoparticles‐loaded DNA vaccine against Vibrio parahaemolyticus was studied. A DNA vaccine was constructed using the outer membrane protein K ( ompK ) gene of V. parahaemolyticus strain (OS4) and pEGFP ‐N 2 , a eukaryotic expression vector, and the construct was named pEGFP ‐N 2 ‐OMPK ( pDNA ). The pDNA was encapsulated in chitosan...