Dairy Goat Journal. Presenting information, ideas, and insights for everyone who raises, manages, or just loves dairy goats.
Tell a Friend about sheep! Magazine
Back Issue
Current Issue
Past Issues
About Us
Contact Us
Breeders Directory

Enzootic Abortion Of Ewes

(Chlamydial Ovine Abortion, EAE)

By Douglas Anderson, DVM

Staff Veterinarian
Colorado Serum Company

In previous issues, we have discussed ovine abortion and campylobacteriosis (vibrionic abortion of ewes).

This article references another common cause of ovine abortion, chlamydial ovine abortion, more commonly known as enzootic abortion of ewes (EAE).

What It Is, Symptoms

Chlamydia psittaci (Antigenic type 1) is the organism responsible for the disease. It is a unique gram negative, spheroidal bacterium that replicates similarly to a virus. It normally requires special microscopic techniques to confirm or identify their presence.

  • Infected ewes may appear sick for several days before they abort late in their pregnancy (last month). They may also deliver stillborn, weak, or premature lambs. In unexposed flocks, the abortion rate may reach 30-50% of the ewes.
  • The abortion may occur the following year, if the exposure occurs after the ewes are pregnant.
  • Ewe lambs exposed prior to weaning may harbor the disease and abort during their first pregnancy.
  • In enzootic areas (areas where the disease is commonly present) abortions will continue each season in the yearling and recently added ewes.
  • Infected rams will show very few symptoms, but breeding will result in a reduced conception rate and possible uterine infections in the ewe.
  • The aborted fetus is usually well preserved, in contrast to an autolytic (already showing signs of decomposition) fetus in campylobacteriosis or vibrionic abortion of ewes.
  • The fetus may be covered with a light beige or a clay-colored, flaky material.
  • The placenta exhibits variable areas of inflammation with hyperemic (reddened) margins and necrotic (decomposing) cotyledons.
  • The areas between the cotyledons will be thickened, granular, and leathery appearing.
  • Following the abortion, a brown uterine discharge is common.
  • The placenta may also be retained and require additional medical attention.
  • In rare cases, mortality of the ewe may result from an unexpelled, mummified fetus. Surviving ewes may become carriers.

How Ewes Get Enzootic Abortion

This disease is contagious and normally spreads through oral or nasal contact, ingestion, or inhalation of contaminated material.

The fetus, placenta, birth fluids, and vaginal discharge from the ewe are all sources of infection.

Isolate the aborting ewes immediately and consult with your veterinarian on recommended treatment, proper disposal of the aborted fetus/placenta, and disinfection procedures.

The veterinarian may also want to perform a necropsy or take samples for an accurate diagnosis.


Prevent the disease from spreading by limiting access to the aborted materials by wild birds and wild or domestic mammals, which may spread the organism.

Take measures to assure that the water supply, drinking area, and feeding area do not become contaminated with the aborted material, or vaginal discharges.

The use of “quarantine” areas, separate boots, coveralls, and plenty of disinfection is highly recommended and cannot be stressed enough. Cleanliness is absolutely essential. Great care should be exercised to prevent human exposure.


This disease can be controlled with the use of a vaccine like Chlamydia Psittaci Bacterin from Colorado Serum Company.

  • Vaccinate all incoming and unvaccinated ewes 60 days prior to breeding season and again 30 days later.
  • Follow up with a booster every year just prior to breeding season. Chlamydial polyarthritis and conjunctivitis are caused by Chlamydia psittaci (Antigenic type 2) and does not allow for adequate cross protection.

For specific management recommendations to control this disease, it is recommended that producers consult with a veterinarian before instituting a prevention or control program.

Colorado Serum Co., Professional Biological Co., & Western Instrument Co. (collectively referred to as Colorado Veterinary Products) manufactures USDA-licensed large animal biologicals and long lasting veterinary instruments. Since 1923, high levels of integrity have earned the respect and trust of producers and veterinarians around the world – ask for any of our company labeled products when consulting with your local veterinarian or animal health supplier. Visit www.coloradovet products.com or call 303/295-7527 for additional information.

©2004 – Colorado Serum Company

Home | Subscribe | Current Issue | Library | Past Issues | Bookstore
Links | About Us | Contact Us | Address Change | Advertise in sheep! | Privacy Policy | Terms of Use |