Optimization o eicacy test or inactivated H9N2 avian inluenza vaccine.
2008
amil Ghadakchi, Hadi | Toroghi, Reza | arzin, Hamid Reza | Kianizadeh, Mehdi | Jahed, Ali Reza | Razmarai | Rezai, Alieh
Avian inluenza AI (H9N2) subtype known as non-highly pathogen, however, causes sever clinical signs and high mortality in commercial chicken locks in Iran. Because o non-highly pathogen nature o the virus, it is not possible to practice eicacy test or the commercial H9N2 vaccines. In this study an eicacy test was developed or H9N2 vaccine. Optimized co-inection o H9N2 and Escherichia coli could cause 30% mortality rates among SP chickens. Sixty ive 10-day-old SP chickens were divided in two groups. The irst group was vaccinated with a commercial inactivated AI vaccine and then challenged with H9N2 and Escherichia coli at 38 and 41 days old, respectively. The remaining chickens were kept as control group. No clinical signs, mortality and virus excretion were observed among vaccinated chickens whereas, depression, coughing, sneezing, gasping, virus excretion along with 20% mortality rates was observed in control group. Pathological signs were included tracheal exudates, with occlusion o bronchi and biurcation o the trachea by ibrinonecrotic casts resulting asphyxia. It seems that co-inection o H9N2 and Escherichia coli method is a new and reliable eicacy test or H9N2 vaccine.
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