Campylobacter bilis caused spotty liver syndrome in laying hens in the Netherlands

Spotty liver disease in laying hens can be caused by Campylobacter hepaticus or by Campylobacter bilis. While C. hepaticus is widely distributed around the world, C. bilis has thus far only been documented in Australia and the USA. We investigated five outbreaks of spotty liver disease in laying hens in the Netherlands. In November 2020 C. bilis was cultured as the causal agent of the outbreak on one of these farms, while C. hepaticus was cultured from hens from the four other farms. Clinical and pathological features were indistinguishable, but MALDI-TOF and WGS identified these species unambiguously. To our knowledge, this is the first report of C. bilis outside Oceania and the USA.