Campylobacter Abortion in Sheep: Causes, Signs, and Flock Control

Campylobacter abortion in sheep, sometimes called ovine campylobacteriosis or vibrionic abortion, is a contagious bacterial cause of reproductive loss. In sheep, the main organisms involved are Campylobacter fetus fetus and Campylobacter jejuni. These infections most often cause abortion in late pregnancy, along with stillbirths or weak lambs.

The disease can appear as a single abortion, but it is especially concerning when it shows up as an abortion storm in the last few weeks before lambing. Some ewes may have few obvious signs before they abort, while others can develop metritis after passing the fetus. On postmortem exam, placental lesions may include hemorrhagic, necrotic cotyledons and thickened or leathery intercotyledonary areas, although field descriptions can vary.

This is not a condition to monitor at home and wait out. Rapid flock-level action matters because contaminated bedding, aborted tissues, birth fluids, feces, and carrier animals can help the bacteria spread. Early veterinary involvement helps protect the rest of the flock and improves the odds of identifying the exact cause of abortion, since several infectious diseases in sheep can look similar.

Campylobacter abortion is caused by infection with Campylobacter fetus fetus or Campylobacter jejuni. Sheep are usually infected by the oral route, meaning they pick up bacteria from contaminated feed, water, bedding, manure, aborted tissues, placentas, or vaginal discharge. Carrier ewes can help maintain the organism in a flock, and some extension sources also note that birds may contribute to spread between groups.

Once introduced, the bacteria can circulate quietly until susceptible pregnant ewes reach late gestation. That is why a flock may look normal for much of the season and then suddenly experience a wave of abortions near lambing. Crowding, poor lambing-area hygiene, and delayed cleanup of aborted materials can all increase exposure pressure.

Not every abortion in sheep is Campylobacter. Other important infectious differentials include Chlamydia abortus, Toxoplasma gondii, Listeria monocytogenes, Coxiella burnetii, Salmonella, and region-specific diseases. Because the outward signs overlap so much, the safest approach is to assume any abortion cluster needs veterinary testing rather than guessing the cause from appearance alone.

Diagnosis starts with flock history and sample collection. Your vet will usually ask when abortions started, how many ewes are affected, gestation stage, vaccination history, recent purchases, lambing-group setup, and whether placentas or fetuses were available. Timing matters because Campylobacter abortions typically cluster in late pregnancy.

Definitive diagnosis relies on laboratory testing, not visual inspection alone. Common submissions include the placenta, fetal stomach or abomasal contents, liver, lung, and the ewe's vaginal discharge or blood, depending on the lab and case. Veterinary diagnostic labs may use culture, PCR, histopathology, or a small-ruminant abortion panel to separate Campylobacter from other infectious causes.

If you can, refrigerate but do not freeze fresh samples unless your vet or lab tells you otherwise. Wear gloves, bag tissues separately, label animals carefully, and document which ewe produced each fetus and placenta. Good sample handling can make the difference between a clear answer and an inconclusive result.

For many US flocks, a practical diagnostic workup may range from about $80-$300 for lab testing per submission, with added farm-call, necropsy, shipping, and herd-consult costs depending on the case. Your vet can help prioritize the most useful tests when budget, timing, or sample quality is limited.

Prevention starts with biosecurity and lambing hygiene. Isolate any ewe that aborts, remove fetuses and placentas right away, disinfect heavily contaminated areas, and keep feed and water away from manure and lambing waste. Quarantine incoming animals, especially replacements from flocks with unknown abortion history, and avoid mixing late-gestation groups more than necessary.

Work with your vet on a vaccination plan if Campylobacter is a known risk in your area or flock. Cornell notes that a vaccine is available, and flock-level prevention is often most effective when vaccination is paired with management changes rather than used alone. Timing matters, so your vet should help schedule doses around breeding and replacement-ewe entry.

Good records are one of the most overlooked prevention tools. Track breeding dates, abortion dates, ewe IDs, lambing groups, and any lab results. That makes it easier to spot patterns early and respond before losses spread. If an abortion occurs, treat it as a diagnostic opportunity, not only an isolated event.

Because Campylobacter and other abortion pathogens can affect people, use gloves, dedicated boots, coveralls, and careful handwashing when handling lambing materials. Pregnant people and anyone who is immunocompromised should avoid contact with aborted fetuses, placentas, and contaminated bedding unless your vet advises otherwise.