BLUE WING DISEASE OF CHICKENS - 1ST CASE-REPORT IN FRANCE

For the first time in France, several cases of a syndrom affecting chickens and looking like the Blue Wing Disease (BWD) were reported from october 1988 to march 1989. Nine cases concerning 13 to 28 days old chickens are reported in this paper. The syndrom always appeared under an acute aspect for 7 to 16 days. Affected chickens were prostrated and died quickly. Cumulated mortality varied from 5 to 12 p.cent. Non affected birds in affected flocks had a normal growth. Suffering chickens showed an exudative and serohaemorragic dermatitis with large ecchymosis under wings, evolving to necrosis. Anaemia was confirmed by hematocrits ranging from 16 to 18 p.cent. Anatomo and histopathologic findings showed a constant and intensive lymphoid atrophy and hypoplasia of bursa of Fabricius, spleen and chiefly of thymus. A seroconversion to chicken anemia agent (CAA) was detected in one affected flock and in another non-affected one close to an impaired flock. Outbreaks of BWD occuring at the same time, in several flocks of broiler-chickens born from the same breeder stocks was strongly suggestive of a vertical transmission. The concerned parent flocks did not show any sign of disease. Horizontal transmission was probably the cause of the seroconversion of a clinically non-affected broiler flock and of a BWD case on 28 days old broilers, these flocks, both, staying next to another affected one.