Infection and Immunity in Fish Models: Insights into Host Defense and Inflammation

Dear Colleagues,

The health of fish populations is paramount for a sustainable blue economy and balanced aquatic ecosystems. This Special Issue, “Infection and Immunity in Fish Models: Insights into Host Defense and Inflammation,” seeks to address the pressing need for a consolidated knowledge base on the pathogenesis of infectious diseases in fish and the corresponding piscine immune defenses. The field is rapidly evolving, moving beyond descriptive studies to a mechanistic understanding of host–pathogen dynamics. Modern tools now allow for the precise manipulation and monitoring of immune genes and pathways, opening new frontiers in disease management.

This edition will provide a dedicated forum for researchers to share discoveries on pathogen virulence factors, such as secretion systems, and the fish immune response markers, including mitochondrial molecules and non-coding RNAs. It will also bridge the gap between basic research and applied solutions, featuring studies on probiotics, alternative feeds, genetic markers for selective breeding (e.g., SNP and DEG analysis), and advanced therapeutics like vaccines and immunoadjuvants. By covering both fundamental and translational science, this collection will be an invaluable resource for microbiologists, immunologists, aquaculture scientists and veterinarians.

We invite you to contribute your original research and review articles to this important endeavor.

This Special Issue will serve as a comprehensive platform to advance our knowledge of fish–pathogen interactions, from the molecular to the organismal level.

We encourage submissions that address, but are not limited to, the following themes:

1. Pathogens Causing Disease in Fish: Discovery and characterization of bacterial, viral and fungal agents impacting both farmed and wild fish populations.
2. Virulence Factors: Molecular mechanisms that enable pathogens to establish infection and cause disease.
3. Patterns of Immune Response to Fish Pathogens: Analysis of immune markers and pathways, including studies on

• mitochondrial molecules in immune signaling;
• microRNAs (miRNAs) as regulators of immunity;
• the application of CRISPR/Cas9 for gene knockout of resistance or signaling genes.

4. Immune Evasion Systems: Mechanisms used by pathogens to subvert host immunity, e.g., Type II, III and IV secretion systems in Aeromonas and other genera.
5. Enhancement of Immune Response:

• Nutritional Strategies: Use of probiotics, protein concentrates and alternative feed sources.
• Environmental Modulation: Impact of factors like salinity variation and exposure to toxic metals.
• Genetic Selection: Application of Single Nucleotide Polymorphism (SNP) analysis for identifying genetic variation and analysis of alleles and differentially expressed genes (DEGs) associated with disease resistance.

6. Experimental Models for Recapitulating Fish Diseases: Development and use of in vivo and in vitro models to study pathogenesis and immunity.
7. Immunoadjuvants: Substances that enhance the efficacy of vaccines and non-specific immunity.
8. Pharmaceuticals: Discovery and evaluation of novel drugs and compounds for treating fish diseases.
9. Vaccines: Design, development, testing and deployment of prophylactic vaccines for aquaculture.

We look forward to receiving your valuable contributions.

Dr. Carla Lima
Guest Editor

Manuscript Submission Information

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• fish models
• infection
• immunity
• host defense
• inflammation