Bacterial Contaminants in Poultry Live Virus Vaccines of Egg Embryo Origin

Abstract

LABORATORIES engaged in the production of viable virus vaccines for poultry recognize the importance of constant attention to the problem of bacterial contaminants that may gain access to these products during one or several stages of production. The very nature of the vaccines precludes any treatment that might render the products bacteriologically sterile. Lyophilization further preserves contaminants that may be present; however, it has the advantage of preventing multiplication which occurs in an improperly handled nonlyophilized product. A large volume of total live virus vaccine production is presently represented by poultry vaccines including those against Newcastle disease, laryngotracheitis, fowl pox, pigeon pox, and infectious bronchitis. Vaccine manufacturers have shown a very active interest in the establishment of better standards through the appointment of a committee by the Veterinary Biological Licensees Association to give attention to this problem. Poultry pathologist groups (Johnson et al.7, Hanson6, Brandly1) are also active in this field and have recommended that bacteriologically sterile products should be