Infectious abortive diseases: Chlamydiosis

Abstract

Chlamydiales order members are intriguing Gram-negative, obligatory intracellular bacteria that divide within eukaryotic hosts and share a distinctive biphasic developmental cycle. The diagnosis of chlamydial infections can therefore be difficult for pathologists, apart from chlamydial abortion in small ruminants like goat and avian chlamydiosis. All members of the Chlamydiaceae family are Gram negative, nonmotile, obligate intracellular bacterial organisms. All of them possess a unique biphasic developmental cycle. The most prominent clinical sign of infection is abortion in goats. However, severe metritis, pneumonia, and keratoconjunctivitis are also recorded in some cases. The clinical picture of abortion with necrotzsing placentitis is sufficient to diagnose chlamydial cause of abortion. Pregnant animals infected in late gestation, but not aborted, may show further abortion in subsequent gestations as they became carriers. Both inactivated and live attenuated vaccines significantly decrease the rate of abortion and shedding of organism. © 2025 John Wiley & Sons, Inc. All rights reserved.