RECENT ADVANCES ON OVINE CHLAMYDIAL ABORTION

This paper reviews new findings on ovine chlamydial abortion. Concerni ng chlamydial taxonomy, with the recent advances due to the analysis o f the ribosomal genes, nine genotypic groups were identified separated into two lineages. It also describes the transmission of the disease, the site of entry of the organism and chlamydial shedding by underlyi ng the role of latent infections. Recent results also concern the path ogenesis, with the kinetics of placental colonization and placental pa thology leading to abortion in ruminants. Studies using experimental i nfection in a pregnant mouse model have allowed the identification of target placental cells and have shown the differential evolution of th e infection according to the stage of pregnancy. Different diagnosis t echniques are compared (ELISA, PCR and immunofluorescence for the dire ct diagnosis) but also the possibilities of distinction between antibo dies against Chlamydia pecorum and Chlamydia psittaci (for serodiagnos is). The recent advances on prophylaxis are presented, as well as the research efforts needs for the next century. (C) Inra/Elsevier, Paris.