Abstract
Chlamydia trachomatis and Listeria monocytogenes are important reproductive tract pathogens in a wide variety of animals including sheep. In humans, chronic or repeated infection of the female genital tract with Chlamydia trachomatis has been identified as a significant factor in the development of occlusive infertility or increased risk of ectopic pregnancy. The aim of this study is to detect circulating immunoglobulins in serum of sheep naturally infected with Chlamydia trachomatis and Listeria monocytogenes in two Egyptian provinces. A total of 82 serum samples from 4 sheep flocks in two Egyptian provinces were examined with enzyme-linked immunosorbent assay ELISA for detection of antibodies of Chlamydia trachomatis and Listeria monocytogenes , The results of ELISA revealed the detection of the two pathogens at a very high percentage (98.78% and 100% for Chlamydia trachomatis and Listeria monocytogenes , respectively) despite of absence of elevated abortion rates in the examined sheep flocks . We can conclude that chlamydial and listerial infections occur frequently in Egyptian sheep flocks, even in the absence of elevated abortion rates and there is possible risk to pregnant women in rural areas where chlamydial and listerial infections in farm animals are widespread. Also, ewes that experienced Chlamydia trachomatis or Listeria monocytogenes induced abortion provide a unique opportunity to study the host: parasite dynamic as it relates to persistent infection. This natural model of persistent infection may, in some ways, be superior to more contrived models in which the chlamydial or listerial isolate is not a normal reproductive pathogen of the study animal. Thus, the study of persistent Chlamydial or Listerial infection in sheep may be used for the benefit of both human and veterinary medicine.

Key words: Keywords: Egypt, Chlamydia trachomatis or Listeria monocytogenes.