Further Studies on Infectious Coryza of Chicken

Infectious coryza is a great problem affecting chickensand results in sever loses. Different trials were conducted toover CDme this serious problems by vaccination. So t this workwas carried out to control the disease in Egypt through outpreparation of six locally prepared mono and bivalent vaccines.In experiment I , the efficacy of six locally preparedvaccines were studied. The protection of four monovalent vaccinesof Haemophilus paragallinarum serotype A (strain 0083) inactivatedwith either formta.line or thiomersal were 85.7’2 and 78.58 percent while it was 85.72 and 85.12 per cent in case of serotypeB (str~in 0222) of Haemophilus paragallinarum respectively.The protection of bivalent vaccines of serotypes A and B withformaline and thiomersal as inactivators were 85.72 and 92.86per cent respectively.In experiment 11 t the potancy of the six locallyprepared vaccines were studied. The protection against challengefive weeks post-vaccination was carried out. The protectionof monovalent Haemophilus paragallinarum serotype A inactivated