What is it ?
Anthrax is an infectious disease caused by a bacterium: Bacillus antracis . This bacterium is characterized by a rod shape (bacillus) and is Gram + type. This Gram stain allows a classification of bacteria according to their morphological characteristics.
The mode of contamination is via the infected animal or ingestion of contaminated animal products. Man can be exposed to the bacteria by manipulating, caressing the animals or even when working with the skin to shape the leather.
There are three well defined modes of contamination:
– skin infection (by transfer through the skin);
– inhalation (pulmonary contamination);
– ingestion (gastrointestinal contamination).
Contamination by skin contact remains the most common mode of transmission. Nevertheless, the inhalation of spores (vegetative multiplication organs) remains a significant form of contamination.
This disease is present throughout the world and concerns both domestic animals and wild animals. The most impacted animal populations are: cattle, sheep, goats, camels and antelopes.
Most cases of anthrax are sporadic cases (affecting only certain individuals in a population, unexpectedly). In addition, outbreaks of infected animals may be visible in France, but generally do not exceed the order of ten.
Coal Disease has been unveiled to the general public following the milestones of 2011 regarding the use of Bacillus antracis in bioterrorism.
Symptoms of Coal disease
Charcoal disease is defined in three forms: the cutaneous form, the gastrointestinal form and the pulmonary form. In this sense, the associated symptoms depend on the type of infection. These can appear anywhere on the body and can extend from one day to more than 2 months.
In the context where the disease is not diagnosed as soon as possible or when the disease is not treated, the clinical manifestations can spread throughout the body and have severe consequences that can lead to lethality. From subject.
- The cutaneous form is characterized by the entry of spores (vegetative multiplication organs) at the level of a lesion of the skin. This type of the disease corresponds to 95% of the cases of the disease of Coal. Associated clinical manifestations are primarily similar to an insect bite. These later evolve towards the formation of an ulcer of size between 1 and 3 cm in diameter. This ulcer is followed by necrosis and can progress to the development of sepsis. This form of the disease is lethal in 20% of cases if effective treatment is not implemented quickly;
- The gastrointestinal form is defined as a result of ingestion by a person of contaminated food. The transmission of the bacteria to humans is via the animal, the food is essentially meat. The symptoms associated with this form of the disease are gastrointestinal. It is an acute inflammation of the digestive tract. The patient with this form of anthrax has nausea, loss of appetite, vomiting, fevers, abdominal pain and severe diarrhea. The mortality associated with this pathological type ranges from 25 to 60%;
- The pulmonary form results in the inhalation of spores (multiplying organs) in the air. The primary symptoms of this form are similar to a cold. However, complications appear quickly (in a few days) and correspond to severe respiratory disorders, major headaches, muscle pain that can lead to septic shock (presence of bacterial toxins in the blood leading to circulatory disorders and impacting the cardiovascular system). In the absence of therapeutic management, this form is lethal for almost all affected subjects.
The origins of the disease
Anthrax most commonly affects ungulate animals, such as sheep, goats or cattle.
People who come into direct contact (skin contact) or indirect contact (ingestion of contaminated meat) with infected animals may develop the disease.
The source of contamination is therefore the animal and the transmission can be done through 3 modes:
Cutaneous infection results in adhesion of the sporadic form of the bacteria through the skin in the presence of a cut, scratch, scar, etc. This is the most common mode of bacterial transmission in anthrax. The major risks of getting infected by the bacteria are contact with the skin, hair or bones of animals. In this sense, the people most at risk of developing the pathology are the subjects in close contact with the animals: farmers, veterinarians, tanners and people working the wool.
Inhalation transmission is the consequence of the presence of bacterial spores in the air. These vegetative forms therefore do not enter the upper respiratory tract of the individual and reach the lungs. The most probable situations when inhaling bacterial spores correspond to the process of tanning the skin of animals or during the treatment of wool.
In addition, the inhalation of spores by an individual does not necessarily mean that it will develop the associated symptoms. In fact, the germination time of the spores extends from 1 to 6 days and the symptoms of this form of the disease only develop at the final stage of germination. In this sense, if the spores are ejected from the body before the end of germination, the symptoms will not develop. Once the spores have sprouted, they release many toxic substances that can cause internal bleeding, edema or destroy some tissues.
Finally, gastrointestinal transmission is effective following the ingestion of infected animals.
Another origin associated with Charcoal Disease is the use of Bacillus antracis as a biological weapon and in bioterrorism.
Risk factors for Coal disease
The risk factors for developing anthrax are close contacts with infected animals (sheep, cattle, ungulate animals, etc.).
The disease is characterized in three forms: cutaneous, pulmonary, gastrointestinal, it turns out that the risk factors are related to direct contact with animals. But also during the ingestion of contaminated meat or during the inhalation of the sporulated form of the bacterium present in the ambient air.
Prevention and treatment of Coal disease
The diagnosis of anthrax depends on the form of contamination.
In case of suspicion of Bacillus antracis infection by inhalation, a chest X-ray is often performed. A pulmonary scan can be used to complete the X-ray examination to confirm or not the diagnosis. The significant radiological manifestations of an infection by inhalations are:
– widening of the mediastinum: region of the rib cage located between the two lungs and containing the heart, the esophagus, the trachea and the bronchial tubes;
– a pleural effusion, the presence of fluid in the pleural cavity (membrane covering the lungs).
Added to the medical imaging examinations, other means make it possible to pose the possible diagnosis of the disease, these include:
– biological tests for measuring the level of antibodies or the level of toxins present in the blood ;
– the analysis of blood samples, injured and infected skin, respiratory secretions, etc.
The usual treatment for anthrax is based on antibiotic therapy: penicillin, doxycycline, ciprofloxacin.
However, the pulmonary form of the disease can also be treated through antibiotic therapy with other drugs. These are usually administered intravenously. The treatment of the disease is often effective in the long term as a result of the spore germination which can be more or less long.
The prevention of this pathology involves the eviction of contact with potentially infected animals. In particular, it is strongly recommended to dispose of carbonaceous animals by incineration or landfill. In addition, vaccination of animals at risk is an effective preventive measure to prevent contamination.
Prophylactic measures (medical means) are also available to prevent the disease.
It is remarkable that animal vaccines are much more effective than those intended for humans.