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bacterial disease Sheep, Goat Vaccine available Transmissible to humans

Sheep salmonellosis

Salmonellosis is an infection caused by bacteria from the salmonella group, of which there are many types. In sheep, it takes three main forms: feverish diarrhea in animals of all ages, a wave of abortions at the end of gestation, and a dev...

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Vaccination Complications When to see a vet Zoonosis Prognosis FAQ Sources Affected species

What is it?

These bacteria are everywhere: in the digestive tract of apparently healthy animals, in contaminated water, in contaminated food, in birds and rodents. Many animals carry them without ever being sick, and begin to eliminate them massively as soon as they are stressed.

This explains the typical onset: the disease breaks out after transport, regrouping, a fair, a sudden change in ration or a period of scarcity. Stress does not create the bacteria, it opens the door for it.

Key point

Salmonellosis kills by dehydration, it affects several animals at the same time and it is transmitted to humans. Handle sick animals and abortions with gloves, keep children away, and call the veterinarian at the first instance.

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:

Diarrhea Fever Reduction Dehydration Blood in stools Loss of appetite Abortion Vulvar discharge Retained placenta Hard or painful abdomen Lying animal that does not get up

In adults and weaned lambs: clear fever, marked depression, refusal to eat, then liquid diarrhea, often dark and foul-smelling, sometimes tinged with blood or containing shreds of mucous membrane.

Rapid dehydration: the eye sinks, the skin of the neck remains wrinkled when pinched, the animal weakens from hour to hour.

Abdominal pain, hunched animal that moans and refuses to have its stomach touched.

Some animals die within a few days; others hang around, lose weight and remain carriers of the bacteria long afterward.

In pregnant sheep: abortions at the end of gestation, often in females who are themselves sick, with fever, malodorous vulvar discharge, retained placenta, and sometimes death of the mother.

In the newborn lamb: devastating form, slaughtered lamb, lying down, which no longer suckles, with or without diarrhea, and which dies within a few hours.

At the herd level, several animals are affected within a few days: it is this grouped nature that distinguishes salmonellosis from an individual problem.

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 infection is caused by bacteria of the Salmonella genus, several types of which affect sheep. Some mainly cause diarrhea, others specialize in the abortion of sheep.

The most common source in a herd is a healthy carrier animal, which has never appeared ill and which begins to eliminate the bacteria under stress.

Contaminated water, contaminated food and fodder, damp litter and soiled pastures maintain the infection.

Wild birds, rodents, cats and farm dogs spread the bacteria into buildings and food supplies.

Stress is the usual trigger: transport, long wait, regrouping, sudden change of ration, famine, birthing.

An animal weakened by parasitism, deficiency or other disease becomes sick more easily and sheds more bacteria.

Any stressful situation: transport, long wait without water, fair, market, and the Eid period when animals change hands, location and ration in a few days.

Mixture of animals of different origins and quarantine-free purchases.

Sudden change of ration, famine, end of drought.

Overcrowding in the sheepfold, damp and dirty litter, poor ventilation.

Contaminated drinking water, drinking troughs never cleaned, ponds and puddles.

Food stocks accessible to birds and rodents.

Lambing period, which brings together fragile females and newborns in the same place.

Lambs having taken colostrum poorly in their first hours.

Animals already weakened by digestive worms, coccidiosis or deficiency.

Transmission

Contamination occurs through the mouth: water, food, fodder, litter and pasture soiled by droppings containing the bacteria.

Healthy carrier animals are the main source within a herd, and there is no way to spot them by eye.

Abortions, fetal envelopes and discharge from aborted ewes are extremely contaminating: they must be handled with gloves and disposed of without delay.

Birds, rodents, farm dogs and cats carry the bacteria from one place to another.

Stagnant water, dirty water troughs and ponds are effective relays.

Equipment, boots, transport vehicles and fair trailers take it from one operation to another.

Humans become infected by putting their hands in their mouth after handling sick animals, runts or soiled litter, as well as by consuming raw milk or undercooked meat.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

The veterinarian first assesses the emergency: in an animal with diarrhea, it is dehydration that kills the quickest, not the bacteria.

The diagnosis is based on laboratory analyses, because no diarrhea is recognizable by eye: culturing of droppings, runts, fetal envelopes or organ samples. Keep the aborts cool, in a closed bag, handling them with gloves, and return them to the veterinarian.

When faced with abortions, he also looks for other common causes in sheep, which require different behavior and several of which are also transmissible to humans. This is all the more reason to never handle a runt with your bare hands.

An antibiogram, produced from the culture, indicates which antibiotics remain effective: salmonella easily develops resistance and treatment chosen at random often fails.

The veterinarian examines water, food, bedding, stock and animal movements to identify the source.

In the event of mortality, an autopsy provides rapid guidance and helps protect the rest of the batch.

Treatment

It is an emergency for the animal as well as for the herd: call the veterinarian at the first case, without waiting for the entire flock to be affected.

The top priority is rehydration. An animal that loses water through diarrhea dies of dehydration before dying of the infection. The veterinarian sets up rehydration by mouth or by infusion depending on the severity.

Antibiotic therapy can be decided by the veterinarian, ideally guided by an antibiogram. It is not justified in all cases: poorly used, it prolongs the carriage of the bacteria and promotes resistance. This choice is never made without veterinary advice, and never with a leftover bottle kept from the previous year.

Anti-inflammatories and supportive care are often necessary.

Isolate sick animals immediately in a separate room, with their own equipment, and deal with them last in the daily round.

Clean and disinfect the premises, renew the litter, empty and clean the drinkers.

Wear gloves for all contact with sick animals, runts and soiled litter, and wash your hands thoroughly afterwards, systematically.

Observe the withdrawal times for meat and milk indicated for prescribed treatments.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Reduce stress, which is the real trigger: short transports, water available on arrival, gradual dietary transitions, stable batches.

Quarantine any animal purchased and avoid returning animals returned unsold from a fair or market to the herd.

Guarantee permanently clean water, clean drinking troughs, prevent drinking from ponds and puddles.

Protect food stocks from birds and rodents, and control rodents in buildings.

Take care of lambing: clean and dry premises, abundant and renewed litter, reasonable density, colostrum given quickly.

Collect and dispose of abortions and fetal casings immediately, wearing gloves, and disinfect the area.

Clean and disinfect buildings between lots, and do not spread fresh manure on plots grazed by young people.

Reserve boots and clothing for breeding, and wash your hands after each handling.

At the same time, control parasitism and deficiencies, which weaken animals.

Vaccination

Vaccines exist in certain countries, in particular against the form responsible for sheep abortions. Their availability varies from one country to another: the question should be asked to the veterinarian, who will indicate what is really accessible locally.

These vaccines do not protect against all types of salmonella: there are a very large number of them, and the protection obtained is targeted. A vaccinated herd may therefore still experience cases due to another type.

Vaccination is especially reasonable in farms which have already experienced episodes of abortions confirmed by the laboratory: it is the analysis result which justifies the approach, not a simple suspicion.

In all cases, it does not replace lambing hygiene, quarantine, or clean water and food.

Possible complications

Death from dehydration within a few days, especially in lambs and weakened animals.

Generalized infection with involvement of several organs, particularly in the newborn.

Long-lasting weight loss and growth retardation in survivors.

Death of the ewe after an abortion, or infection of the uterus with lasting infertility.

Prolonged carriage of the bacteria in cured animals, which maintains the infection and causes it to emerge during the following stress.

Contamination of premises and plots, with relapses during sensitive periods.

Contamination of the human environment, particularly children and vulnerable people.

Installation of resistance to antibiotics when treatments are given without analysis.

When to see a veterinarian

Several animals from the same batch have diarrhea with fever: call immediately.

Watery, dark or blood-tinged diarrhea appears in a slaughtered animal.

An animal is dehydrated, lying down, and never gets up.

A ewe aborts at the end of gestation, especially if it is itself sick: keep the abort cool in a closed bag, with gloves, for the veterinarian.

Multiple abortions occur in the same herd in a short period of time.

Newborn lambs die within hours without prior signs.

The disease appears after transport, a fair or a change of ration.

A person on the farm presents fever and diarrhea during the episode: they must consult a doctor and report contact with the animals.

Transmission to humans

Salmonellosis is transmitted to humans, in whom it causes gastroenteritis: fever, abdominal pain, sometimes bloody diarrhea, vomiting. In young children, the elderly, pregnant women and weakened people, the infection can be serious and requires prompt medical attention.

Contamination occurs through hands brought to the mouth after contact with sick animals, runts, litter or manure, as well as through raw milk, raw milk products and undercooked meat.

Precautions around an affected herd: gloves for handling sick animals, runts and fetal envelopes; careful hand washing with soap after each contact and before eating or smoking; clothing and boots reserved for breeding; prohibition of access to young children in affected premises.

Pregnant women should not participate in lambing or handle runts, due to the risk of salmonellosis and other abortive flock diseases.

Do not consume raw milk from animals that are sick or under treatment, and cook the meat thoroughly.

If a person on the farm presents a fever with diarrhea during an episode in the herd, they must consult a doctor and report their contact with sick animals.

Prognosis

An animal caught early, rehydrated and treated according to the veterinarian's advice most often recovers, even if recovery takes time.

Newborn lambs affected by the generalized form have a very poor prognosis: they often die before any treatment.

Sheep that abort can recover, but some die and others remain infertile for a long time.

At the herd level, the outcome depends on the timeliness of isolation, cleaning and correction of stressful conditions. Without this, the disease emerges at each sensitive period, maintained by the carrier animals.

Frequently asked questions

My sheep have diarrhea after returning from the fair, is it serious?

This is a classic salmonellosis situation: transport, waiting and changing rations awaken a bacteria that animals were already carrying. Isolate the sick, give clean water and call the veterinarian. Febrile diarrhea that affects multiple animals should never be treated indiscriminately.

Am I risking anything for my family?

Yes, it's a zoonosis. In humans, it causes gastroenteritis which can be serious in children, the elderly and frail people. Wear gloves, wash your hands with soap after each contact, keep boots reserved for breeding, keep young children away and do not consume raw milk from sick animals.

A sheep has aborted, what should I do with the runt?

Never touch it with bare hands. Put on gloves, place it with its husks in a closed bag, keep it cool and give it to the veterinarian for analysis. Disinfect the location. Several abortive diseases of sheep are transmissible to humans, and pregnant women should not go near them.

Can I give an antibiotic that I already have on the farm?

No. Salmonella is easily resistant, and a poorly chosen antibiotic does not cure the animal while prolonging the carriage of the bacteria. The veterinarian relies on a laboratory analysis to know what works. In the meantime, what saves the animals is rehydration.