Anthrax: Description
Anthrax (also called anthrax) is caused by the bacterium Bacillus anthracis. The name is based on the observation that the spleen of deceased persons has a brownish-burnt appearance upon autopsy.
The bacillus is able to form resistant spores and thus survive in the soil for decades. It is passed on almost exclusively via animals or animal material. Human-to-human transmission has not yet been described.
Subsequently, there have also been individual cases of suspicious mailings in Europe, as well as reports of suspicious containers or traces of white powders.
Anthrax is considered a significant threat by public health authorities worldwide, both through normal infection routes and through bioterrorism.
Anthrax: Occurrence
Humans (especially in industrialized countries) are very rarely infected with the bacterium. It mainly affects people who have close contact with farm animals. Every year, there are about 2000 cases of the disease worldwide.
In addition, since 2000, several drug users in Europe (including Germany) who had injected heroin presumably contaminated with anthrax spores (injection anthrax) have fallen ill. In addition, there was one case of illness in the United Kingdom after inhalation of contaminated heroin.
Anthrax: mandatory reporting
Medical laboratories are also required to report anthrax.
Anthrax: symptoms
At the beginning of the disease, signs are not very specific for anthrax. Symptoms initially affect the area that first came into contact with the bacillus. Thus, different organs may be primarily affected by anthrax depending on the route of infection:
Cutaneous anthrax
In addition, the lymph vessels become inflamed and the lymph nodes swell. A fluid-induced swelling (edema) around the inflamed area is also characteristic. Tissue damage is often severe and can affect deep tissue layers.
Pulmonary anthrax
Pulmonary anthrax resembles sudden-onset pneumonia with bronchitis. This makes it difficult for physicians to diagnose anthrax early. Signs of illness include a range of severe general symptoms such as chills, vomiting and coughing up blood. The bloody sputum may be infectious.
Pulmonary anthrax is the most dangerous form of anthrax because it can severely affect breathing. If left untreated, it leads to death within a few days.
Intestinal anthrax
Here, too, the symptoms are initially non-specific: patients develop a high fever combined with diarrhea, nausea, vomiting and loss of appetite. Later, there may be severe bleeding in the intestine, which manifests itself with bloody diarrhea. The disease can progress to peritonitis, which is very difficult to control even with massive therapy. This form also leads to death if left untreated.
Special form of injection anthrax
Symptoms begin very variably between one and ten days after injection. Patients develop massive tissue swelling (edema) and abscesses with severe inflammation starting around the injection site. Affected tissue areas may die.
Anthrax: causes and risk factors
The anthrax pathogen Bacillus anthracis is a rod-shaped bacterium that has a protective capsule and produces dangerous toxins. These can damage blood vessels, causing bleeding. Under unfavorable environmental conditions, the pathogen forms spores. In this inactive form, it can survive in the soil for decades.
Humans become infected primarily through skin contact with diseased animals, infected carcasses or contaminated animal products (such as wool, meat). In the process, the anthrax pathogen can enter the body via small skin injuries (e.g. insect bites) and then trigger cutaneous anthrax. The bacillus cannot penetrate through intact skin.
Anthrax: examination and diagnosis
It is important to diagnose anthrax early. This is because the disease is fundamentally life-threatening. However, early treatment can often prevent a severe course of the disease.
In addition, blood samples are taken.
The pathogen can be detected by cultivating bacilli in the patient’s examination material and then detecting them under the microscope. It is also possible to look for snippets of the bacillus genome, amplify them by polymerase chain reaction (PCR) and thus detect them unequivocally.
In further investigations, the cultivated pathogens can be tested for their sensitivity to various antibiotics (resistance diagnostics). The results help in therapy planning.
Anthrax: Treatment
Anthrax patients are primarily treated with antibiotics. The exact nature of this antibiotic therapy (type of active ingredients used, duration of treatment, etc.) depends primarily on the symptoms and the severity of the disease.
If meningitis has developed as a complication of anthrax, it must also be treated with appropriate antibiotics.
In addition to antibiotic therapy, surgical intervention is sometimes performed: in the case of injection anthrax with severe skin-soft tissue infections, the damaged tissue must be surgically removed as part of debridement. Surgical intervention is also sometimes required for cutaneous anthrax.
Obiltoxaximab is approved in combination with antibiotics for the treatment of patients infected by inhalation of anthrax spores. The active ingredient may also be used in certain cases to prevent such inhalational anthrax (see “Anthrax: Prevention” below).
Anthrax: course of the disease and prognosis
Anthrax is a very rare but serious disease that can take a severe course despite targeted antibiotic therapy. The earliest possible start of therapy is crucial for the chances of recovery.
Pulmonary anthrax is particularly dangerous; without treatment, almost all sufferers fall victim after just a few days. Even if treatment is initiated in good time, almost half of all patients with pulmonary anthrax – as with intestinal anthrax – die. For injection anthrax, the prognosis is only marginally better. Here, even with therapy, the infection leads to death in around one in three patients.
If the treatment is effective, the regression of symptoms, especially those of the skin, may take days to weeks. For this reason, antibiotic therapy should not be discontinued prematurely because of apparent ineffectiveness.
Long-term effects of anthrax have also been described. These include, above all, increased fatigue and rapid physical exhaustion.
Anthrax: Prevention
Direct transmission of the pathogen from person to person has not yet been described, but cannot be ruled out. Therefore, anthrax patients are isolated; caregivers must observe increased protective measures.
There is also a vaccination against anthrax. It is mainly indicated for at-risk persons in regions where anthrax is more common (endemic areas). In Germany and Austria, no anthrax vaccine is available in the short term. In Switzerland, such a vaccine is also not available – and, moreover, not licensed.
