Abstract: In order to evaluate prevalence of swine Chlamydophila abortus in Beijing intensive pig farms, 507 blood samples were detected for antibodies using indirectly hemorrhage assay (IHA) and ELISA while 183 clinical samples were determined for positive antigens by immunofluorescence test kits(IF), including 166 samples from pig swabs and pig sperms and 17 throat swabs from pig farmers. The positive antibody against Chlamydophila abortus was 4.14% (IHA) and 2.17%(ELISA), respectively while the average positive antigen was average 14.8% (IF). Moreover, the higher antigen positivity was found in the boar sperm samples, sow virginal swabs and in throat swabs from pig farmers,which accounted for 37.5%, 27.5% and 23.5%, respectively in the survey. On contrary to the previous reports, the positive antibody in Beijing intensive pig farms was found to be lower prevalence than the other province. Our investigation firstly explored that Chlamydophila abortus was prevalence in intensive pig farms as well as in the closely human beings. The urgent measure should be taken into account for cutting transmission from boar sperms to sows and human beings.

Key words: Chlamydophila abortus pigs; antibody; antigen; investigation