Enterococcus cecorum outbreaks has emerged in broiler flocks all over Europe, with considerable economical and animal welfare consequences. The infection has a broad range of manifestations (e.g. pericarditis, arthritis, osteomyelitis, and sepsis) leading to increased mortality. Currently, little is known concerning transmission and pathogenesis in broilers and their parents.
Consequently, a set of experimental E. cecorum infections were conducted in broiler breeders and broilers. The bacteria was inoculated at two doses using intravenous (IV), intratracheal (IT) and oral (PO) route of infection in both bird types. Full post mortem (PM) and bacteriological investigation 3, and 10 days after infection were performed. Bacteriology was performed daily on the eggs from the parent birds.
After IV infection of the broiler breeders (high dose) a pronounced egg drop and decreased appetite was observed. Despite very mild or no lesions the majority of the high dose group demonstrated low grade bacteraemia at both time points. In the low dose group no lesions was observed and only 1 bird had bacteraemia. No clinical signs, PM lesion or positive bacterial re-isolation was observed. No E. cecorum could be detected from the egg content.
In the broilers, all birds in the IV high dose group died within 12h of peracute sepsis, despite massive bacteraemia very few lesions was observed. The PM findings in the low dose IV group resembled the field outbreaks, with severe pericarditis as the major manifestation. The IT and PO infections are on-going.
The preliminary results indicate a clear age-related difference in susceptibility of E. cecorum infections, also suggesting dose dependant and transmission route differences.. There is no indication of a genuine vertical transmission to the offspring via the egg content. The final results will give novel insights into the transmission and pathogenesis of infections E. cecorum in broilers and their parents.