Immunogenicity of an E. coli pili vaccine in chicken

The immunogenicity of an oil emulsified Escherichia coli (serotype 078) pili vaccine was evaluated in chickens. Chickens were vaccinated with 18 microgram per dose of pili protein at one week and three weeks of age and challenged with homologous serotype 078 as well as heterologous serotype 02 via posterior thoracic air sacs. Unvaccinated chickens were challenged to serve as positive controls. Vaccinated chicks were protected against challenge because the vaccinated chicks exhibited low mortality, mild gross and histopathological lesions in air sacs, pericardium and liver, and reduced adhesion index (AI) and adhesion ratio (AR) to mucosal colonization in homologous as well as heterologous groups than the positive controls.