The bacterium can be cultured from the liver and bile of infected birds, although recovery from non-sterile organs such as the caecum and duodenum remains elusive.
Subsequently, an Australian group isolated and further characterised a genetically similar bacterium and named it Campylobacter hepaticus. In 2015, a novel fastidious thermophilic, microaerobic campylobacter was isolated from symptomatic SLD flocks in the UK. However, none other than treatment with antibiotics has been consistently effective which suggested a bacterial aetiology.
Control measures trialled include use of antibiotics, improved biosecurity and hygiene, as well as management practices directed at reducing stress in flocks. Histopathology reveals a multifocal acute hepatocellular necrosis with fibrin and occasional haemorrhage. A presumptive diagnosis at post mortem is made with the detection of characteristic small yellow-white necrotic hepatic lesions, together with a fibrinous peri-hepatitis, excess pericardial and peritoneal fluid, and usually enteritis with diarrhoea. Indicators of SLD include an acute drop in egg production of up to 35%, together with increased mortality of up to 15%. Outbreaks usually, but not exclusively occur in young layers (≅25 weeks) at peak of lay.
The disease occurs almost exclusively in barn and free-range production systems. Spotty Liver Disease is an acute infectious disease of layer chickens that was likely first described in the USA and Canada in the 1950s and 1960's.