Experimental Production of "Breast Blisters" by S-6 Type Mycoplasma

REAST blisters, keel cysts, or bursa synovalis presternalis have been apparent in chickens since about 1930.10 Since 1941 the reported incidence of breast blisters has been greater in male birds,6,1013 in heavy breeds,1 6,13,14 and in birds with fewer breast feathers.4 Other reports indicate that the condition can be produced or aggravated by mechanical irritants such as wet litter,9'12 litter of inadequate depth,2 litter of large particle size,'2 wire floors,9 and roosts.9,1 It has also been reported that breast blisters are a rare sequela of chronic respiratory disease7 and that they occur in birds infected with the type of Mycoplasma that produces infectious synovitis.3 This paper reports the experimental production of a distinctive type of breast blister by S-6 type Mycoplasma (Mycoplasma gallisepticum).