Chlamydial infections in small ruminants.

Chlamydophila abortus (formerly Chlamydia psittaci) is one of the most important causes of reproductive failure in sheep and goats, especially in intensively managed flocks. The disease is usually manifested as abortion in the last 2 to 3 weeks of gestation, regardless of when the animal was infected. Ewes that abort are resistant to future reproductive failure due to C. abortus, but they become inapparent carriers and persistently shed the organism from their reproductive tracts during estrus. Chlamydophila pecorum is the other member of the genus that affects small ruminants, and it is recognized as a primary cause of keratoconjunctivitis in sheep and goats and of polyarthritis in sheep.