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Bacterial anthrax

Anthrax is a very serious bacterial disease of herbivores, which most often kills the animal within a few hours. It is also a serious zoonosis: it is transmitted to humans, particularly when handling dead animals and their products. The bac...

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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?

The bacteria responsible has a formidable property: upon contact with air, it forms spores, extremely resistant forms of survival which persist in the soil for decades. This explains the existence of plots deemed dangerous, where the disease reappears from time to time.

In the vast majority of cases, the breeder does not see the sick animal: he finds it dead, often with dark, non-coagulated blood flowing from the nose, mouth or anus, a quickly bloated belly and a lack of stiffness in the corpse.

Key point

Health emergency and serious zoonosis. Disease notifiable in many countries, including Tunisia: any suspicious case, and in particular any sudden death with discharge of non-coagulated blood from natural orifices, must be reported immediately to the veterinary services. Never open, skin or consume a dead animal under these circumstances.

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:

Fever Reduction Lying animal that does not get up Difficulty breathing Rapid breathing Edema Fall in milk production Tremors Seizures Blood in stools

Sudden death is the most common presentation in cattle: the animal is found dead without anything having been noticed the day before.

When signs are observed, they often last only a few hours: very high fever, deep depression, animal which isolates itself, staggers, then lies down and never gets up again.

Rapid and difficult breathing, very congested mucous membranes.

Sudden cessation of rumination and appetite, immediate drop in milk production.

Tremors, then convulsions in the terminal phase.

Edematous swellings, particularly in the throat, chest, stomach or sides, in certain forms.

Emission of blood from the nose, mouth, anus or vulva, usually at or shortly after death.

On the corpse: dark blood which does not coagulate, belly which swells very quickly, rigor mortis absent or very weak. These three elements combined should raise suspicion of charcoal and prohibit any opening of the body.

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 disease is caused by the bacteria Bacillus anthracis.

Exposed to air, this bacteria transforms into spores capable of resisting heat, drought and ordinary disinfectants, and surviving for decades in the soil.

Animals become contaminated by ingesting these spores while grazing, especially when the grass is short and they tear up the earth with them.

Once in the body, the bacteria multiplies very quickly, invades the blood and releases powerful toxins which cause rapid death.

The rise of spores to the surface after a flood, a marked drought or earthworks explains the sudden reappearance of the disease on previously affected plots.

Areas known to have already experienced outbreaks: the spores persist there for a very long time.

Dry season with short grass, or on the contrary period following floods, which bring the spores to the surface.

Earthworks, digging, pond cleaning on formerly contaminated land.

Absence of vaccination in an endemic area.

Summary burial or butchering of dead animals on site: this is what maintains homes from one generation to the next.

Family slaughter of sick or dead animals: this is the main cause of human contamination.

Transmission

In cattle, by ingestion of spores present in soil, soiled grass, water or contaminated food.

By the carcasses of animals dead from the disease: they seed the ground with spores as soon as they are opened by a knife, a scavenger or decomposition.

By contaminated foods or by-products, in particular poorly controlled meals of animal origin.

In humans: by contact with the skin, especially through a cut, during butchering, rendering or handling contaminated hides, hair and wool; by eating undercooked meat from a sick animal; by inhalation of dust laden with spores, a rare but very serious form.

The disease is not transmitted from one person to another.

Diagnosis and care

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

In the event of sudden death, immediately call the veterinarian and veterinary services. Do not open the body, do not move it, do not leave it accessible to dogs or scavengers.

The diagnosis is made on a blood sample taken in a very supervised manner by the veterinarian, generally from a superficial vein, without opening the animal, then examined and confirmed in the laboratory.

The authorities then decide on the measures: elimination of the corpse by incineration or deep burial according to the rules in force, disinfection of the site, placing animals in the herd under surveillance, emergency vaccination and treatment of exposed animals.

People who have handled the animal must consult a doctor without delay and report exposure: treatment exists and is all the more effective the earlier it is taken.

No meat, milk or leather from a suspect animal should be consumed, sold or used.

Treatment

Treatment is only likely to be successful if it is started very early, which is rare given the speed of progression.

It is based on antibiotic therapy prescribed and administered by the veterinarian; penicillins and tetracyclines are part of the families used. The doses, route and duration are exclusively his decision.

Animals in the herd exposed to the same risk are taken care of according to the instructions of the veterinarian and veterinary services: preventive treatment and vaccination are organized in a precise order, because an antibiotic administered at the wrong time cancels the effect of the vaccine.

No self-medication is acceptable for this disease: it exposes people, complicates the diagnosis and wastes time.

Milk from sick or treated animals should not be consumed or marketed.

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

Prevention

Vaccinate animals in areas where the disease is known, every year and before the risk period, according to the instructions of the veterinary services.

Never open, cut up or bury a suddenly dead animal yourself: notify the veterinarian immediately.

Dispose of corpses according to official instructions, by cremation or deep burial in the right place: a poorly disposed corpse recontaminates the soil for decades.

Avoid grazing plots at risk during periods of drought or just after earthworks, and prevent animals from grazing at ground level.

Fence off and report areas where an outbreak has occurred.

Never consume or sell the meat of an animal found dead.

Wear gloves and wash your hands thoroughly after handling sick animals; disinfect the equipment according to the recommendations of veterinary services, ordinary disinfectants being ineffective on spores.

Vaccination

A live spore vaccine exists and has been used for a long time in cattle, sheep and goats.

In endemic areas, annual vaccination of the entire herd before the risk season is the most effective prevention measure.

It is most often organized by veterinary services as part of official campaigns: contact them and your veterinarian.

Antibiotics and this vaccine should not be given at the same time, as the antibiotic will prevent the vaccine from working. The order and timing are determined by the veterinarian.

After an outbreak, emergency vaccination of exposed animals is one of the measures decided by the authorities.

Possible complications

In animals, the disease is most often fatal within a few hours: there is little room for complications, only speed.

Long-lasting contamination of the soil of the plot when the corpse has been opened or improperly disposed of, with reappearance of cases years later.

Spread to other animals in the herd and to neighboring herds.

Human contamination: the cutaneous form is the most common and can be treated well if caught in time; the digestive and respiratory forms are much more serious.

When to see a veterinarian

An animal is found dead suddenly, without prior illness: call the veterinarian first and do not open the corpse.

Dark, non-coagulated blood flows from the nose, mouth, anus or vulva of a dead animal: this is a health emergency, notify the veterinary services immediately.

Several animals die in a short time in the same lot or on the same plot.

An animal has a very high fever, deep depression, tremors, or rapid swelling of the throat or stomach.

You have handled, butchered or consumed a dead animal in these circumstances: consult a doctor immediately and report the exposure.

A painless blackish skin sore appears on your hand or arm after handling an animal: seek medical attention immediately.

Transmission to humans

Bacterial anthrax is transmitted to humans and can be fatal: this is why the instructions must be followed without exception.

Contamination occurs mainly through the skin, when butchering or handling a dead animal, contaminated leather, hair or wool. The bacteria enters through a cut or scrape and causes a sore which deepens and becomes blackish, usually not very painful. Taken in time, this form treats well; neglected, it can become generalized.

Contamination by ingestion of undercooked meat from a sick animal causes a serious digestive form.

Inhaling dust laden with spores when working with leather or wool causes a rare but very often fatal respiratory form.

Rules to be absolutely respected: never open or cut up a suddenly dead animal, particularly if it is bleeding from its natural orifices; never consume or sell the meat or milk of a sick or dead animal; wear gloves and wash your hands and forearms thoroughly after handling animals; do not let children approach a corpse; notify veterinary services immediately.

The disease is not transmitted from one person to another. Any exposed person must consult a doctor without delay and inform them of contact with a suspicious animal: early treatment exists and is very effective.

Prognosis

In cattle, the prognosis is poor: death most often occurs before the animal can even be treated.

Only animals taken into care from the very first hours have a chance of surviving.

At the scale of the herd and the region, the situation is perfectly controllable: annual vaccination in risk areas, correct disposal of corpses and immediate reporting are enough to make the outbreaks disappear.

The worst scenario remains the opening of a corpse on the plot: it transforms an isolated accident into lasting contamination of the land.

Frequently asked questions

Why should you not open a suddenly dead animal?

Because the bacteria only forms its resistant spores on contact with air. As long as the body remains closed, it remains confined. By opening it, you release spores which contaminate the soil for decades and you expose yourself to serious illness. Inform the veterinarian: the sample is taken without opening the animal.

Can I eat or sell the meat of an animal found dead?

Never, regardless of the supposed cause of death. In the case of anthrax, the consumption of undercooked meat causes a serious digestive condition in humans, and butchering is the main cause of contamination.

Bacterial anthrax and symptomatic anthrax, are they the same disease?

No, they are two different diseases, caused by two different bacteria. Symptomatic anthrax affects the muscles of young cattle and is not transmissible to humans. Anthrax is a serious zoonosis. As they may look similar at first glance, any sudden death must be examined by the veterinarian before any handling.

My animals have never been sick, should I still vaccinate?

If you are in an area where cases have already been reported, yes: the spores remain in the soil for decades and can emerge after drought, flooding or construction. Annual vaccination before the risk period is organized with the veterinary services.