Although H9N2 is a virus of low pathogenicity, syndromes such as respiratory complex, egg drop and possibly associated high mortality rates have been reported under field conditions.

Vaccination is widely used in enzootic countries to control the disease,
Gallimune 308 is a trivalent inactivated vaccine that protects against Infectious Bursal Disease (IBD), Newcastle Disease (ND) and Avian Influenza H9N2 (AI). The vaccine is widely used in day-old broiler chicks in order to confer an early protection. In the present trial, performed by Veterinary Organization of Iran (IVO) and Pilvarad poultry diseases department in Jan. 2006, the efficacy of Gallimune 308 in broiler chickens was evaluated under field conditions.

The trial was carried out on 20.000 day-old broilers, housed in 2 separate houses A and B. Gallimune 308 (0.2 ml SC) was administered on day 1 to chicks in house A and Gallimune 208 (0.2 ml SC) to house B. Other vaccinations were carried out according to routine farm schedule.

SAMPLING

10 blood samples each from houses A & B were collected at 1, 8, 13, 18, 35, and 53 days of age for ND and AI HI tests and IBD ELISA (Synbiotics IBD+ kits).
The MG and MS status of the day old chicks were negative.
SEROLOGICAL TESTS AND TRIAL PARAMETERS
The following parameters were compared between house A and B:

• IBD Test: IBD antibody titre kinetics
• ND Test: ND antibody titre kinetics
• AI Test: AI antibody titre kinetics
• Mortality and FCR

CONCLUSION
According to the comparison of ND, AI and IBD antibody kinetics, the comparative mortality rate (6.5% house A vs. 11.6% house B) and the comparative FCR range showing 35 points of improvement in vaccinated house (2.06 house A vs. 2.41 house B), the efficacy of Gallimune 308 vaccine is completely confirmed.
The high mortality rate and FCR range of house B (where the Gallimune 308 was not used) was due to IBD disease which began on day 25. Associated high IBD-Ab titers were also seen in house B.

Walid AL SALEH
Boehringer Ingelheim AH, Amman, Jordan

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^{Information from the Avian Flu Forum hosted by Boehringer on April 2017}