Infectious Coryza (IC) is a poultry disease caused by Avibacterium paragallinarum which affects respiratory system and causes economic losses (decrease of laying production and increase of culling rate in growing chickens). Av. paragallinarum is classified into three serovars with endemic presence in countries like India. Development of trivalent inactivated IC vaccines is a strategy to protect chickens. Adjuvants are required to improve their efficacy. MONTANIDE™ ISA 71 R VG (ISA 71R) is an adjuvant designed to resist to destabilizing antigenic media such as bacteria. In this study, we evaluated the performance of ISA 71 R formulated in a trivalent IC vaccine.
Firstly, 30 layers were injected at D0 and D21 with a trivalent vaccine based on ISA 71R. Vaccine stability was tested and efficacy was assessed by a virulent challenge at D35. The vaccine was stable and induced 100% protection against all three serovars.
Then approximately 100,000 layers distributed in 4 farms with high infectious coryza prevalence in Southern India were vaccinated with the same ISA 71R vaccine in a prime/boost protocol. Injection sites were inspected and mortality was monitored during 7 days post vaccination. Egg production and mortality were recorded weekly up to 17 months of age and compared to standard mortality and egg production. No untoward effects were observed after vaccination. No incidences of infectious coryza were observed during production period. Egg production and the mortality rate were similar to what is observed in a healthy flock.
The vaccine adjuvanted with ISA 71 R VG is efficacious in controlling IC in field conditions.
Keywords: Infectious Coryza, egg production, vaccine, adjuvant, Montanide ISA 71 R VG.
Abstract presented at the 3rd International Symposium on Alternatives to Antibiotics 2019.