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Abortive campylobacteriosis
Abortive campylobacteriosis is caused by bacteria of the Campylobacter genus which settle in the digestive tract of ewes, then reach the uterus of pregnant females and kill the lamb before term. It is one of the major causes of serial abort...
What is it?
Abortive campylobacteriosis is caused by bacteria of the Campylobacter genus which settle in the digestive tract of ewes, then reach the uterus of pregnant females and kill the lamb before term. It is one of the major causes of serial abortions in sheep. It is not transmitted from a ram to a ewe during mating, contrary to what its nickname vibriosis suggests: in sheep, everything starts from the mouth, from contaminated food, water or bedding. The disease has a very recognizable signature for the breeder: abortions occur at the end of gestation, they multiply over several weeks, and it is especially young ewes lambing for the first time that are affected. An isolated abortion means nothing on its own. Several abortions in the same batch, however, require a search for the cause with the veterinarian, because campylobacteriosis closely resembles, from the outside, brucellosis, Q fever, abortive chlamydia or toxoplasmosis. None of these diseases are visible to the eye, and some are dangerous for the family.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Abortions in the last third of gestation, often without the ewe having appeared ill the day before.
Lambs born prematurely, dead or too weak to suckle, which die within the first hours.
Lambs at term but weak, unable to get up, although the ewe seems normal.
Brownish or bloody vulvar discharge that persists for several days after the abortion.
Retention of the placenta in some females.
Most sheep that abort are not sick: this is what confuses and wastes time.
A minority develops an infection of the uterus after abortion, with fever, depression, refusal to eat, and can die if nothing is done.
At the flock level: abortions occurring over several weeks, empty ewes at the end of the campaign, a number of weaned lambs much lower than expected.
On aborts, the veterinarian looks for specific liver lesions, which only he must handle and interpret.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The responsible bacteria normally live in the intestines of carrier animals which show no signs: apparently healthy sheep, cattle, wild birds, poultry.
These carriers eliminate bacteria in their droppings. A pregnant ewe that swallows these bacteria with feed, hay, water or bedding passes the infection into its bloodstream, then into the placenta.
The placenta is damaged, the lamb is no longer fed properly and dies, or is born too weak to survive.
An aborting ewe then sheds huge amounts of bacteria in the runt, placenta and discharge. It is at this moment that it contaminates its fellows: the first abortion creates the following ones.
This explains the typical unfolding in waves, over several weeks, starting from one or two isolated cases that no one had taken seriously.
Primiparous ewes, that is to say those giving birth for the first time: they have not yet encountered the bacteria and are the most affected.
Last third of gestation, period when the disease is expressed.
Lambing in buildings, in tight batches, with litter rarely replaced.
Food distributed on the ground, low troughs soiled with droppings, dirty drinkers.
Introduction of animals purchased without quarantine, in particular young pregnant females.
Regrouping of herds, transhumance, return of pension, purchases on the markets before Eid.
Abortions left in the park or thrown on the manure pile accessible to animals and dogs.
Absence of separation of ewes which have aborted from the rest of the flock.
Transmission
Contamination occurs through the mouth: food, fodder, water or litter soiled by droppings or by the products of an abortion.
The main danger comes from ewes which have just aborted: the runt, the husks and the discharge are loaded with it. Leaving a runt in the barn or in a pen means contaminating the entire lot.
Hands, boots, pitchforks, wheelbarrows and troughs carry the bacteria from one enclosure to another.
Dogs, cats, birds and rodents can drag a runt and spread the bacteria far and wide.
Breeding is not the route of transmission in sheep: treating the ram does not solve anything.
Human beings become contaminated by putting their hands in their mouth after touching an abortion, contaminated equipment, or by drinking raw milk.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
Never try to make the diagnosis yourself: the main causes of abortion in sheep all give the same picture and some are transmissible to humans.
Call the veterinarian after the second abortion in a flock, and even after the first in a young ewe or if the ewe is sick.
Keep the abortion and placenta cool, in a closed bag, without handling them with bare hands: these are the most useful samples in the laboratory, and they are often thrown away before the veterinarian arrives.
The veterinarian analyzes the abortion, the placenta and blood samples from several ewes. At the same time, he searches for other causes, in particular brucellosis, Q fever, abortive chlamydia and toxoplasmosis, because the action to take and the risk for the family are not the same.
A single series of samples done well costs less than an entire lambing campaign lost.
He also examines ewes that have aborted, looking for a uterine infection that requires rapid treatment.
Treatment
An abortion that has already occurred cannot be reversed: the objective of the treatment is to protect ewes that are still pregnant and to save those with an infection of the uterus.
Ewes that abort with fever, foul-smelling discharge or marked depression require antibiotic treatment and general support, decided by the veterinarian.
In a herd experiencing a wave of abortions, the veterinarian can offer collective antibiotic treatment for females that are still pregnant, possibly incorporated into the feed. This decision is up to him: it depends on the identified cause, the stage of gestation and the type of production, and it never replaces the isolation of females who have aborted.
No antibiotic should be given on its own initiative or repeated from a previous campaign: a poorly chosen treatment masks the signs, distorts the analyzes and lets the disease continue.
Waiting times for meat and milk must be requested from the veterinarian and strictly respected, particularly in the run-up to Eid or an animal sale.
Alongside the treatment, the actions that matter most are free: immediately isolate any ewe that has aborted, pick up the runt and placenta, clean and change the litter.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Immediately isolate any ewe that has aborted, and keep it away while the discharge lasts. This is the most effective measure of all.
Pick up the runt and the placenta with gloves, in a closed bag, and have them disposed of according to regulations: never in the accessible manure pile, never with dogs, never left in a corner of the park.
Disinfect the location, remove soiled litter and mulch abundantly.
Quarantine any purchased animals, especially young pregnant females, and talk to the veterinarian before mixing them.
Distribute the fodder and concentrate in racks and troughs that animals cannot soil with their droppings.
Protect food supplies from birds and rodents, and clean water troughs regularly.
Allocate young ewes separately from adults during lambing: they pay the heaviest price.
Avoid mixing batches of different origins just before lambing.
Vaccines against bacterial abortions in sheep exist in certain countries: their availability varies and this question must be asked to the veterinarian, who knows what is really accessible locally.
Vaccination
There is not a vaccine available everywhere against this disease, and its availability depends on the countries and periods.
The question nevertheless deserves to be asked to the veterinarian on farms which suffer waves of abortions year after year: only he knows what is really accessible and what makes sense in the situation of the farm.
In the absence of a vaccine, prevention relies entirely on lambing hygiene, the isolation of ewes that have aborted and the correct disposal of runts.
Possible complications
Infection of the uterus after abortion, which can lead to fatal generalized infection.
Ewes that do not recover, remain thin and do not resume pregnancy the following season.
Collapse in the number of lambs born alive and weaned over an entire campaign.
Installation of the infection in the herd, with new cases in the following years among new young females.
Contamination of family members, particularly children and vulnerable people.
Significant indirect cost: empty sheep to feed for a whole year, early culling, renewal purchases.
When to see a veterinarian
Two or more ewes abort in the same flock, even within a few days of each other.
A young sheep aborts: this is the typical profile of several contagious diseases, do not attribute it to an accident.
A sheep has a fever, no longer eats or remains lying down after an abortion: consult without delay.
A smelly vulvar discharge persists for several days.
Lambs are born at full term but too weak to suckle, several times in the same campaign.
At the end of the season, an unusual number of ewes turn up empty.
A person in the family who has handled an abortion has a fever or diarrhea: they should consult a doctor and tell them that they have been in contact with an animal abortion.
Transmission to humans
The bacteria responsible for this disease are among the most common causes of diarrhea in humans. The risk is real, although it is rarely serious in a healthy person.
Contamination occurs through hands brought to the mouth after touching a runt, a placenta, soiled bedding or lambing equipment, and through the consumption of raw milk.
In humans, this results in sometimes bloody diarrhea, stomach pain and fever. Medical advice is necessary, always specifying contact with animals that abort.
Absolute rule at lambing: never handle an abort or a placenta with bare hands. Gloves, closed bag, hand wash with soap afterwards, clothes and boots cleaned.
Pregnant women should not attend to lambing or approach ewes that have aborted, whatever the supposed cause: several diseases responsible for abortion in sheep, such as Q fever, abortive chlamydia and toxoplasmosis, are dangerous for human pregnancy. This rule also applies to children and immunocompromised people.
Do not consume raw milk from a recently aborted sheep.
Prognosis
The sheep itself generally recovers well, unless an infection of the uterus sets in.
A female who has aborted acquires good protection and most often has a normal pregnancy in the following seasons: this is not a reason to systematically cull her.
On a herd scale, the wave of abortions died down on its own within a few weeks, but the campaign was lost.
The prognosis for the following years depends almost entirely on the hygiene of lambing and the management of the young females, which remain the fragile link.
Frequently asked questions
Only one sheep aborted, should I be worried?
An isolated abortion does not mean anything on its own: it can be accidental. What should trigger a search for a cause is repetition. If there are two or three abortions in the same flock, or an abortion in a young ewe, call the veterinarian. Waiting often costs an entire campaign.
Is my ram responsible, should I change it?
No. In sheep, this disease is not transmitted during breeding: contamination passes through the mouth, with contaminated food, water or bedding. Changing the ram changes nothing, while picking up the runts and isolating the ewes that have aborted changes everything.
What to do with the runt and the placenta?
Collect them immediately, with gloves, in a closed bag, and notify the veterinarian: these are the best samples to identify the cause. They should never be left in the park, thrown on accessible manure or given to dogs. A runt left behind contaminates the entire lot.
My wife is pregnant, can she help me with lambing?
No, and that's a rule without exception. Several diseases responsible for abortion in sheep can seriously affect human pregnancy. A pregnant woman must neither attend lambings, nor touch a runt, nor handle the clothes and boots used in the sheepfold.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 11 August 2026
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