Laboratory and field trial assessment of protection given by a Salmonella enteritidis PT4 inactivated, adjuvant vaccine.

An inactivated Salmonella enteritidis PT4 vaccine, containing 10(9) cfu ml-1 and 75% oil-adjuvant, was used in a laboratory and field trial. Vaccination at day old and 4 weeks subcutaneously provided good protection against massive challenge with 10(8) cfu of virulent organisms administered intravenously at 8, 12 and 16 weeks of age. The degree of protection was assessed according to the severity of the clinical signs, mortality, postmortem lesions and the recovery of the challenge organisms from postmortem material in vaccinated and unvaccinated challenged birds.