Genotypic Characterization of Emerging Avian Reovirus Genetic Variants in California

Area of Science:

• Veterinary Virology
• Molecular Epidemiology
• Avian Pathology

Background:

• Avian reoviruses are significant pathogens causing tenosynovitis in poultry.
• Monitoring viral evolution and genetic diversity is essential for effective disease control.

Purpose of the Study:

• To isolate and characterize avian reoviruses from a tenosynovitis outbreak.
• To determine the genetic diversity and evolutionary dynamics of these viruses.
• To perform full genome sequencing for comprehensive analysis.

Main Methods:

• Virus isolation from clinical samples (tendons, joints, heart, intestines).
• Partial S1 gene sequencing for genotypic clustering.
• Full genome sequencing of selected isolates.

Main Results:

• 265 avian reoviruses were isolated, predominantly from tendons and joints.
• Six distinct genotypic clusters (GC1-GC6) were identified, with GC1 and GC6 being most prevalent.
• A temporal shift in cluster representation was observed, with a decrease in GC1 and an increase in GC6 strains.
• Full genome sequencing revealed L3, S1, and M2 genes as major contributors to viral variability.

Conclusions:

• The study provides insights into the epidemiology of avian reoviruses in California.
• Genetic variability, particularly in capsid protein genes, is a key feature of these viruses.
• Understanding reovirus evolution aids in developing better disease management strategies.