Sheep Enzootic Abortion: Disease, Welfare and Prevention

Enzootic abortion of ewes (EAE), caused by Chlamydia abortus, is a major infectious disease causing significant welfare harm to sheep and economic losses to farmers.

Key Facts

Enzootic abortion is the leading infectious cause of sheep abortion in the UK and Europe
The causative bacterium, Chlamydia abortus, can survive in the environment for weeks under favorable conditions
Infected ewes typically abort in the last 2-3 weeks of pregnancy or produce weak, non-viable lambs
Infected animals shed massive amounts of bacteria at abortion, infecting naive animals in the same group
The disease also poses a risk to pregnant women - human infection can cause miscarriage
Vaccination with a live attenuated vaccine is highly effective at preventing disease in naive ewes
Once a flock is infected, the disease can become endemic and very difficult to eradicate without vaccination and management

Welfare Considerations

Enzootic abortion causes substantial welfare harm at multiple levels. Ewes that abort experience the physical trauma of abortion, which can involve retained fetal membranes, secondary infection, and systemic illness. The stress response to abortion is significant, and ewes with retained membranes may develop metritis causing additional suffering. Weak lambs that survive birth often struggle to thrive, experiencing cold stress, failure to suckle, and frequently death. The cyclic nature of the disease - infecting new cohorts each season - means welfare impacts recur annually in unmanaged flocks.

What You Can Do

Vaccinate replacement ewe lambs before their first breeding season in EAE-affected flocks
Isolate aborting ewes and carefully dispose of aborted material to prevent spread
Practice strict biosecurity when purchasing sheep - quarantine new arrivals for at least 3 weeks
Wear gloves and take hygiene precautions when assisting ewes at lambing in affected flocks
Consult a veterinarian immediately when abortion rates increase to establish the cause
Report suspected EAE to your vet for confirmation testing - accurate diagnosis guides appropriate management