Coryza still occurs frequently but that doesn’t mean it can’t be controlled. Efforts to maintain biosecurity and improve management are not optimal if not supported by vaccination. The diversity of serovars that cause Coryza makes it important to choose a vaccine that homologous to circulating isolates.
Avibacterium paragallinarum serovar A, B and C are widespread in various countries, including Indonesia, Malaysia, Vietnam, People’s Republic of China (PRC), Pakistan, Iran and Egypt. Based on Research & Development Medion analysis using the polymerase chain reaction (PCR) method on Coryza isolates for the last 5 years, serovar A, B, C1 and C4 were found circulating in Indonesia. The dominance of 49% of the isolates was identified as C4 serovar with distribution in almost all regions in Indonesia (Graph 1). It was reported on GenBank that serovar C4 was also found in Iran.
The results of the cross-protection test against 9 Avibacterium paragallinarum serovar based on the Kume Scheme showed that there was only partial cross-protection between serovars. Serovar C4 provides the best protection for homologous serovar only. It is important to select a vaccine that is homologous to the circulating serovar.
Medivac Coryza Q and Medivac Coryza Q Suspension are inactivated vaccines containing 4 Avibacterium paragallinarum serovars, serovar A, B, C2 and C4 to prevent Coryza infection in poultry. These 2 vaccines are formulated with different adjuvants. Adjuvants in vaccines play a role in increasing the immune response. Medivac Coryza Q Suspension uses a suspension adjuvant with faster release antigen and a lighter vaccine solution when injected, so it is recommended as a prime-vaccination. Medivac Coryza Q with emulsion adjuvant will released slowly so that immunity lasts longer. Therefore, Medivac Coryza Q is suitable as a booster.
The results of the challenge test on layer chicken vaccinated with Medivac Coryza Q Suspension and Medivac Coryza Q showed that the chickens were protected from the challenge of Coryza bacteria since the pre-layer period (Graph 2). This proves that Medivac Coryza Q and Medivac Coryza Q Suspension are able to produce optimal immunity that can overcome the challenges of Coryza bacteria.