Modern approaches to the production of inactivated vaccines against chicken cholera

Abstract

Introduction. Chicken cholera is one of the most dangerous avian infectious diseases, causing significant economic damage to the industrial poultry production. Chicken cholera usually occurs in septic form, and causes high morbidity and mortality (60–80%), but recently it has become chronic, subclinical and associated. Inactivated emulsion vaccines are used worldwide to prevent chicken cholera and provide high and long-term immunity. However, there is a problem with residual reactogenicity of inactivated vaccines, particularly of the bacterial variants. This problem can be solved by using safer, next-generation adjuvants. The aim of the article is to study the physical and biological properties and determine the optimal inoculation volume and method of administration of inactivated vaccines against chicken cholera , based on different adjuvants.Materials and methods. Formaldehyde inactivated culture of P. multocida st. 115and a number of adjuvants (“Montanide GEL-02” and oil adjuvants “Montanide ISA 70 VG” and “Montanide ISA 78 VG”) were used for vaccine production. The vaccine samples were tested for sterility, stability and viscosity by conventional methods. Determination of reactogenicity and antigenic activity of the vaccines was carried out on young 30-days old chickensof egg-laying type.Results. The vaccine sample based on the adjuvant “Montanide ISA 70 VG” containing 1.5 billion P. Multocida microbial cells in a single immunizing dose of 0.3 cm3 was found to be the best among the tested preparations. When assessing the reactogenicity, it was obvious that all samples, regardless of the type of adjuvant, showed more pronounced residual reactogenic properties when injected intramuscularly into the chest muscle than when injected subcutaneously into the middle third of the neck.