Mycoplasma synoviae Infection in Chickens By SHIZUO SATO

Disease caused by Mycoplasrna s11noviae, so far called infectious synovitis, shows symptoms such as joint swelling, lameness, pale comb, and retarded growth mainly of chicken and turkey. This disease, first noticed in a broiler raising area of U.S.A., was reported by Olson et al. and Wills in 1954. Since then the disease has been recognized in European countries and South Africa•>. In Japan, although the occurrence of synovitis caused by this mycoplasma in field-raising chickens was not yet confirmed, two strains of M. synoviae were isolated from the material taken from a chicken processing plant in Kyushu district by Shimizu et al. (1971) 1 >. On the other hand, Yoder ( 1970) > ma.de clear that frequent occurrence of airsacculitis in the broiler flocks, not being infected by M. gallisepticurn, in U.S.A. was a result of the infection of M. synoviae. At that time, number of broilers condemned at processing plants due to airsacculitis was reported to be 8-25%, and the antibody survey of breeding flock found out that about a ha.If of the breeding flock showed positive reaction at a rate of as high as 8090% . As to the factors inducing airsacculitis by M. synoviae, it was e:. It was also known that the extent of causing airsacculitis and synovitis were different by strains of M. synoviae. Thus, the recent trend is, with regard to the disease caused by M. synoviae, that more interest is given in airsacculitis than in original infectious synovitis. In Japan, although there seems to be no occurrence of synovitis as stated above, it is considered that the respiratory tract infection may exist as in U.S.A. In order to examine this aspect, study on method of serological diagnosis practically applicable was carried out. In the present paper, practical usefulness of the diagnostic antigen prepared for the test and isolation of M. synoviae from the respiratory tracts of field-raising chickens will be described briefly.