Prevalence of subclinical infectious bursal disease and its significance in India.

From a total of 32 poultry flocks, 1,176 serum samples were screened by the agar gel precipitation test and 314 (26.7%) were positive for antibodies to infectious bursal disease virus (IBDV). Prevalence of infection on the farms ranged from 8.88 to 53.84 per cent. The prevalence was highest (61.82%) in chickens between 7 and 11 weeks old and lowest (3.92%) in those above 22 weeks of age. In commercial broilers and layers 51.61 and 17.78% respectively were seropositive reactors. The high prevalence of subclinical IBD and its economic significance are discussed.