Infectious Diseases in Aquaculture Fish

Aquaculture production faces persistent challenges from a spectrum of infectious agents that compromise fish health, welfare and farm productivity. Viral pathogens such as members of the Iridoviridae family (notably megalocytiviruses including infectious spleen and kidney necrosis virus), herpesviruses and nodaviruses are responsible for rapid onset systemic disease and high mortalities in cultured species. Bacterial pathogens, especially Aeromonas hydrophila, Vibrio spp. and Francisella noatunensis, add further burden through septicaemia and chronic granulomatous infections. Horizontal transmission via water, contaminated equipment or carrier stocks underpins the rapid spread of infection, while environmental stressors such as temperature fluctuations, stocking density and poor water quality exacerbate disease outbreaks. Advances in molecular detection, immunoprophylaxis and genomic epidemiology have improved our understanding of host–pathogen interactions, revealing mechanisms of immune evasion, viral latency and co-infection synergy. Vaccination strategies against key viral and bacterial targets, selective breeding for disease-resistant lines and non-invasive monitoring approaches are being integrated into husbandry to mitigate risk. However, emerging genotypes and shifts in pathogen virulence demand ongoing surveillance and a multidisciplinary approach to sustainable disease control in global aquaculture.

Research from Nature Portfolio

Recent studies have elucidated the role of viral genome methylation in immune evasion and pathogenicity. Mapping of cytosine methylation across the double-stranded DNA of a piscine iridovirus revealed a hypermethylated genome architecture essential for efficient viral amplification in host cells. Experimental reduction of methylation levels triggered robust innate immune responses in vitro and markedly decreased pathogenicity in vivo, indicating that methylation modulates host recognition. The findings provide a molecular basis for targeted antivirals and suggest that epigenetic modulation could be exploited in vaccine design or attenuated virus development to enhance protective immunity in cultured fish.

Infectious Diseases in Aquaculture Fish publication trend

The graph below shows the total number of articles in infectious diseases in aquaculture fish across all publications each year (not limited to Nature Index journals).

Technical terms

Genome hypermethylation: Addition of methyl groups to viral DNA cytosines, altering immune detection and replication efficiency.

Quantitative PCR (qPCR): A molecular method that amplifies and quantifies DNA targets in real time using fluorescent probes or dyes.

Droplet digital PCR (ddPCR): A partitioned PCR technique that provides absolute quantification of nucleic acids by analysing thousands of nanoliter droplets individually.

Environmental DNA (eDNA): Genetic material shed by organisms into water, enabling non-invasive detection and monitoring of pathogens in aquatic environments.

References

1. Hypermethylated genome of a fish vertebrate iridovirus ISKNV plays important roles in viral infection. Communications Biology (2024).
2. Development of a Propidium Monoazide-Based Viability Quantitative PCR Assay for Red Sea Bream Iridovirus Detection. International Journal of Molecular Sciences (2023).
3. A droplet digital PCR method for the detection of scale drop disease virus in yellowfin seabream (Acanthopagrus latus). Frontiers in Microbiology (2024).
4. Application of Environmental DNA for Monitoring Red Sea Bream Iridovirus at a Fish Farm. Microbiology Spectrum (2021).