Use of PCR for extranous agent testing in avian vaccines

Quality control of biologicals, in particular avian vaccines, includes certification of freedom from extraneous agents (EA). Adventitious viruses have always represented a major concern as a potential risk associated with the use of biologicals. Extensive testing for the presence of potential extraneous agents is therefore required to ensure the safety of the vaccines. To replace the use of laboratory animals (the Three Rs-approach) we developed and implemented a series of alternative PCR tests for detection of extraneous agents in avian viral vaccines (the PCR-approach). The application of PCR to screen poultry vaccines for viral contaminants is an example of how PCR can be usefully employed in quality control assays. The object of this work is to show how the use of in vitro methods can contribute to reduction in animal testing in the quality control of biologicals.