POSSIBLE ASSOCIATION OF SULPHONAMIDE COCCIDIOSTATS WITH ENHANCED SUSCEPTIBILITY OF CHICKEN TO INFECTIOUS BURSAL DISEASE

Résumé

Infections bursal disease (IBD) outbreak in 3 commercial poultry farms were reported. The diagnosis of the disease was based on clinical signs and pathological lesions, following by laboratory confirmation by the Ouchterlony agar precipitation test. All the affected chickens were from vaccinated flocks. Very high mortality and morbidity were recorded: 61% mortality form flocks where coccidiosis were used compared with 31% and 32% mortalities from flocks where coccidiosis vaccines were used. A retrospective and prospective investigation of mortality patterns in the rearing flocks of these three farms, without IBD outbreak between 1999 and 2002 indicated 8.3% average mortality when sulphonamide coccidiostats were used as against 4.3% average mortality when coccidiosis vaccines were used. It is suggested that sulponamide coccidiostats administration might be a precipitating factor of the heavy losses recorded during IBD outbreak.