In vivo host-pathogen dynamics and immune responses to Piscirickettsia salmonis using the zebrafish model

Area of Science:

• Aquatic Animal Health
• Infectious Diseases
• Immunology

Background:

• Piscirickettsia salmonis is a significant pathogen in salmon aquaculture.
• Existing host models are insufficient for studying P. salmonis infections in vivo.
• Developing effective infection models is crucial for understanding disease pathogenesis.

Purpose of the Study:

• To establish and validate zebrafish as a surrogate host model for P. salmonis.
• To visualize and analyze host-pathogen interactions during P. salmonis infection.
• To investigate the immune response to P. salmonis in vivo.

Main Methods:

• Utilized transgenic zebrafish with fluorescent immune cells.
• Employed fluorescent dyes and protein markers to track host-pathogen interactions.
• Analyzed immune gene expression in infected zebrafish larvae and adult kidneys.

Main Results:

• Observed a significant increase in neutrophils, indicative of emergency granulopoiesis.
• Detected P. salmonis in the caudal hematopoietic zone of infected zebrafish.
• Confirmed elevated expression of immune markers (mpx, interleukins, interferons) in response to bacterial burden.

Conclusions:

• Zebrafish are a suitable and valuable model for studying P. salmonis infections.
• The study elucidated key aspects of the host immune response, including emergency granulopoiesis.
• Findings provide a foundation for further research into P. salmonis pathogenesis and control strategies.