Experimental studies on brucellosis in chickens.

The present study was carried out on 30 one-day old and 50 six-months old chicks in two separate experiments. Exposure of one-day old chickens to Br. abortus showed no apparent clinical signs, although the microorganism was recovered from 2 out of 10 infected cases. 40% of chicks which were exposed to Br. melitensis showed signs of illness 48-72 hours post infection with fatal termination within 12-36 hours after onset of symptoms. The microorganism was isolated from 6 out of 10 infected chicks. Adult chicks, when exposed to Brucella infection showed no clinical signs except a slight decrease in egg-yield among hens infected intraperitoneally with Br. melitensis, although brucella organisms were recovered from droppings, egg-shell, egg-yolk and white, and from internal organs of some chicks. Bacteriological evaluation of diagnostic procedures showed that Rose Bengal and Brucellosis card tests were efficient for the diagnosis of brucellosis in chickens. The brucellin test proved its efficacy when applied in the wattle, better than in wing-folds with a peak of reaction within 48 to 72 hours post inoculation. Brucella organisms isolated from experimentally infected chicks were identical to the original strains used. In droppings of chicks Br. melitensis survived for 48 days at room temperature (12-22 degrees C). Beside the economical losses resulting from infection by Br. melitensis of one-day old chicks, the results obtained assure the significance of infected chicks, their eggs and droppings in disseminating brucellosis for man and animals.