FieldDxEnzootic Abortion of EwesClinical signs, differential diagnosis, treatment and prevention in goats and sheep.
Overview
The single largest infectious cause of ovine abortion in several countries, and a significant human health risk to pregnant women. Chlamydia abortus. Marked urgent in FieldDx. Zoonotic: this condition can pass to people.
Clinical signs
- No illness before abortion; behavioural change and vulval discharge may appear only in the final 48 hours of pregnancy.
- Abortion or stillbirth typically in the last 2-3 weeks of pregnancy; placenta shows necrotic, reddish-brown cotyledons with thickened, exudate-covered intercotyledonary areas.
- Lambs that survive to term may develop fever, lethargy, dyspnea, nasal discharge and pneumonia.
Predisposing factors
- Caused by Chlamydia abortus; the single largest infectious cause of ovine abortion in several countries; spreads at lambing via infected placental material.
Look-alikes to rule out
Treatment
Long-acting tetracyclines in the face of an outbreak may reduce further abortion losses; isolate aborting ewes and dispose of placental material carefully.
Prevention
Vaccination where available; isolate ewes close to lambing from the rest of the flock; strict hygiene at lambing.
Source
MSD Veterinary Manual — Chlamydiosis in Animals (accessed 2026-08-11)
WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals — Chapter 3.8.5, Enzootic abortion of ewes (ovine chlamydiosis), 2018 (accessed 2026-10-29)
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