Survey Interaction Between Avian Influenza Subtype H9N2 and NDV Lasota Vaccine in The Analysis of Serological Test Results

During the breeding season, commercial poultry flocks are exposed to various viral, bacterial, mycoplasma, and fungal infectious agents. Vaccination and field challenges are examples of this infectious. Isolation, serological test, and molecular diagnosis were used to evaluate the vaccine response and laboratory diagnosis. Analysis of the serum response is one of the diagnostic challenges between laboratories and clinicians.  The aim of this study was to investigate the effect of avian influenza virus infection on the results of Newcastle vaccines in poultry flocks. To do this, the effect of influenza (H9N2) respiratory infection on serum response to live Newcastle disease vaccine was investigated and the results of hemagglutination inhibition test were analyzed. The results showed that the presence of avian influenza virus increased the serum response to the Newcastle disease vaccine and increased the titer's dispersion so that in the study of the titers, some of the titers appeared to indicate disease. It can be analyzed that the influenza virus may have caused inflammation of the trachea to increase the penetration of the vaccine virus into the trachea and create a stronger immune response. In fact, this study demonstrates the synergistic effect of the H9N2 influenza virus and the Lasota vaccine virus. In poultry farms and especially broiler farms, due to the multiplicity of vaccines used and the high volume of challenge, for serological testing, it is recommended that a complete serum profile be used to survey titers all common respiratory factors.