Genomic and pathogenicity studies on campylobacter hepaticus, the agent responsible for spotty liver disease in chickens

Spotty Liver Disease (SLD) causes significant economic losses to the poultry industry, causing mortality of up to 11% for up to 6 weeks and up to 25% reduction in egg production. The cause of the disease was recently identified as Campylobacter hepaticus. To investigate possible mechanisms of pathogenesis, we studied multiple genomes of C. hepaticus isolated from different parts of Australia. By comparison to the HV10 reference genome, the Northern QLD isolates 19L and 54L showed higher variation than the other isolates from Southern parts of Australia including Victoria, New South Wales and South Australia. Some isolates carry plasmids that encode tetracycline resistance. Challenge studies in chickens found that different C. hepaticus isolates have different levels of virulence.