A Capillary Tube Agglutination Test for Detecting Antibodies against Ornithosis in Turkey Serum

Abstract

A capillary tube agglutination test using a Giemsa-stained, buffered suspension of elementary bodies prepared from a toxigenic turkey strain of ornithosis virus propagated in the allantoic cavity of chicken embryos was compared with the indirect complement fixation test, and the results were promising. The CTA test seemed to be more sensitive in the first week or two after infection, and thereafter the two tests seemed equally sensitive. Both were a little more sensitive than the direct complement fixation test when the test material was turkey serum. In the CTA test false positive reactions were encountered, usually in low serum dilutions, but occasionally in dilutions as high as 1:32, when the serum was hemolyzed, contaminated or contained residual fibrin. Reactions at dilutions of 1:16 or higher constituted good presumptive evidence of infection or of some previous encounter with ornithosis agents; reactions at dilutions of less than 1:16 were less specific and were interpreted cautiously. Preliminary testing of serum from infected parrots and pigeons indicated that the CTA test can detect ornithosis antibodies in these species. The CTA test is economical and simple to perform. According to the results of these tests it could be a useful flock test, of value in epizootiologic surveys, and a rapid screening test of flocks before marketing in enzootic or epizootic areas. Flocks undergoing acute or subacute epizootics of ornithosis, the most dangerous from the standpoint of public health, could be detected easily.