IPSF: Is Castellaniella a primary pathogen?
Castellaniella in broiler breeders resulted in increased mortality
3 June 2026
1 minute read
By: Editor's note: The following is from a presentation by Yi Chen Luo and colleagues at the University of Georgia, USA, and Prairie Livestock, Canada, during the 2026 International Poultry Scientific Forum.
Increasing evidence suggests that Castellaniella causes fatal disease in chickens and other animals. Recent reported cases associated with Castellaniella ginsengisoli in commercial broiler breeders presented increased mortality, lameness and swollen wattles. Since all cases involved commercial broiler breeders, the aim of this study was to validate the pathogenicity of C. ginsengisoli.
To establish a reliable infection model, three potential inoculation routes were tested: oral, subcutaneous, and intramuscular over a two-week trial with groups of 60-week-old healthy commercial broiler breeders. Clinical signs varied among individuals, with the most severely affected birds dying within the first week. Examination of these birds showed splenomegaly and hepatomegaly, both with diffuse white foci and hemorrhages, as well as atretic or coagulative changes in ovarian follicles.
Birds that survived the acute phase developed a chronic form of the disease, characterized by lameness in the second week. In addition to the lesions described above, these chronically affected birds also presented with femoral head necrosis and swollen knee and hock joints with tenosynovitis. The birds from the uninoculated group (control) remained healthy throughout the course of the experiment.
C. ginsengisoli was reisolated on blood agar and it was detected from the liver, spleen, follicles, hock joints and blood samples of sick birds, demonstrating that C. ginsengisoli has the potential to cause disease as a primary pathogen.
