Anthrax is a very rare disease that generally affects wild game and livestock. It is caused by a bacterium that can be spread through indirect or direct contact with infected animals. Though rare in the developed world, certain regions are at higher risk of anthrax. This article will take an in-depth look at this deadly disease as well as address some frequently asked questions.
Anthrax may be something you have never heard of. It is rather uncommon in the Western world, however there are certain regions of the world that deal with this disease on a more regular basis. Ranging from the Caribbean to Asia, Africa and even some parts of Europe, these regions have a much higher prevalence of anthrax due to being large agricultural hubs. Therefore, it is not surprising that people who deal with livestock and game-rearing in these regions are at particular risk for this life-threatening disease. Other groups who may encounter infected animals are also in danger of contracting anthrax. Although considered a rare disease, anthrax is still considered life threatening and can result in serious health complications.1,2
Causes of anthrax
Anthrax is caused by a spore-forming bacterium, Bacillus anthracis, which is found naturally in soil in certain parts of the world. Despite being dormant for years, the spores can still infect hosts, even years later. Domestic and wild livestock such as cattle, horses, goats, and sheep are popular hosts for anthrax. Transmission of anthrax usually occurs through inhaling spores, consuming contaminated meat, or exposure to infected animals. Contact with contaminated items has also been shown to cause anthrax. There have been some incidents of contracting anthrax through making traditional African drums out of infected animal skins.3
Although there has not been any evidence so far to prove that person-to-person transmission has occurred, there is some possibility that forms of anthrax that produce skin lesions could be contagious, either through direct contact or contamination. In Europe, new evidence has been found that demonstrates anthrax being contracted through injecting intravenous drugs, such as heroin.4
Signs and symptoms of anthrax
There are many types of anthrax, each with their own signs and symptoms.
These can be categorised into:
- Cutaneous anthrax
- Gastrointestinal anthrax
- Inhalation anthrax
- Injection anthrax
In most cases of anthrax, symptoms will begin six days after exposure to the bacteria. However, this can vary depending on the type of anthrax developed, with some forms staying dormant for up to four to six weeks.5
Cutaneous anthrax is an infection that is localised to the person’s skin. It is the most common route of transmission of this disease.
Cutaneous (meaning skin-related) infection is transmitted through a wound or cut in the skin. When the skin barrier is broken, the anthrax-causing bacteria can enter the body easily. It usually presents as an itchy raised bump, similar to common insect bites. However, this small bump develops into a sore with a black centre very rapidly. Although this is the most common way to get anthrax, it is also the mildest form of the disease and is rarely fatal. The symptoms are most often flu-like, such as headaches and fever with some swelling of the skin and possibly lymph glands.5,6
This form of anthrax is contracted through consuming meat from an infected animal. The entire gastrointestinal tract can be affected, from throat to colon.
Signs and symptoms of this form of anthrax are similar to that of food poisoning, such as nausea, vomiting, and abdominal pain. There may also be fever and loss of appetite, as well as swelling of the throat and neck leading to difficulties with swallowing. In more advanced stages of the disease, severe and bloody diarrhoea is also common.7
The deadliest form of anthrax is inhalation anthrax, which is caused by breathing in the anthrax spores. The symptoms can start off similar to other forms of the disease, such as flu-like symptoms and nausea, but can also develop into much more severe symptoms like difficulty breathing and meningitis. Inhalation anthrax is often fatal, even with medical intervention and treatment.6
Injection anthrax is a relatively new subgroup of the anthrax disease. So far, it's only recorded incidents have only been in Europe. This type of anthrax is contracted through the injection of illegal drugs. Some signs and symptoms include significant swelling and redness at the site of injection, shock, meningitis, and multiple organ failure.5
Management and treatment for anthrax
The treatment and management of anthrax is highly dependent on multiple factors such as:
- Mode of transmission
- How you were infected
- Overall health, how fit and healthy you are
- Other risk factors such as pre-existing conditions
Treatment for anthrax is most effective when started as soon as possible.
The most common treatment is antibiotics such as levofloxacin, doxycycline, and
ciprofloxacin. These can be administered as a single antibiotic or a combination, depending on the disease severity and treatment plan. As well as antibiotics, other forms of intensive care may be provided depending on the severity of the anthrax. Ventilators, fluids, and medicines that aid in constriction of blood vessels and blood pressure monitoring may also be given.8
Not all types of anthrax respond to antibiotics, therefore certain subcategories of anthrax have more specialised treatment options available.
For inhalation anthrax, in addition to antibiotics, anti-toxin therapies such as obiltoxaximab and raxibacumab have been developed. These medications eradicate the toxins produced by the infection instead of tackling the bacteria responsible for the disease. Anthrax immunoglobulins have also been used to aid in the neutralisation of these toxins. However, for advanced inhalation anthrax, the bacteria often produce more toxins than the antitoxins can eliminate.9
Additionally, a few cases of injection anthrax have been treated with surgery to remove any infected tissue.
How is anthrax diagnosed?
Since the symptoms of anthrax are similar to influenza, an influenza test is usually performed to rule it out. If it is found not to be influenza, a variety of additional tests are used to confirm an anthrax diagnosis. These normally include skin testing such as biopsies, blood tests, chest X-rays, and in some cases, a spinal tap.1
How can I prevent anthrax?
For most of the public, prevention of anthrax is limited to avoiding any infected animals if you live in or travel to a country with high anthrax rates. There is also an anthrax vaccine available for certain high risk groups, such as scientists and military personnel.1
Who is at risk for anthrax?
In order to contract anthrax, direct contact with the spores must take place. Certain high-risk groups are more prone to coming into contact with anthrax such as:
- Anyone who handles animal fur, wool or skins particularly from regions with high rates of anthrax
- Anyone who dresses and handles game animals, as there have been known to be some outbreaks of anthrax in domestic cattle even in communities with low rates of anthrax
- Veterinarians, particularly those who work with livestock
- Scientists who handle anthrax bacteria
- Military personnel who may be deployed in countries with high rates of anthrax
- Anyone who injects intravenous drugs such as heroin10
What are the types of anthrax?
Anthrax can be subcategorised into four main types:
- Cutaneous anthrax
- Gastrointestinal anthrax
- Inhalation anthrax
- Injection anthrax
What are the complications of anthrax?
The main complications of anthrax are very serious and can include organ failure, sepsis, and inflammation of the brain, which can lead to bleeding and ultimately death.11
How common is anthrax?
Anthrax is very rare in the developed world; however, particular regions have a higher prevalence.
The regions with the highest prevalence of anthrax are present in agricultural regions of:
- the Caribbean
- Central/South America
- Eastern/Southern Europe
- Central/Southwestern Asia2
Is anthrax contagious?
Anthrax is not considered contagious in the sense that it cannot be spread between people like a common cold or flu. Anthrax is commonly contracted through bacterial spores, although there have been some reports of person-to-person transmissions through contact with skin lesions in certain patients with cutaneous anthrax.3
When should I see a doctor?
If there is any chance you may have come into contact with anthrax bacteria, for instance through being part of a high risk group, or coming into contact with animals or consuming meat in places with a high prevalence of anthrax, you must seek immediate medical attention. The complications of anthrax are severe, and early diagnosis and intervention are essential to successful treatment.
Anthrax is a rare disease caused by bacterial spores. It is most prevalent in certain parts of the world such as Africa and Asia, and is most likely to affect certain groups such as farmers, vets, and military personnel who are based in those specific areas. Signs and symptoms of anthrax can often begin like influenza, but it has much more serious outcomes than a common cold, even leading to death. If there is any risk of exposure to anthrax, you must seek medical attention and early intervention. Prevention is possible by limiting exposure to any contagious animals. Vaccines are available for high risk groups, but not to the general public at this time.
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- Swartz MN. Recognition and Management of Anthrax — An Update. N Engl J Med [Internet]. 2001 [cited 2023 Mar 9]; 345(22):1621–6. Available from: http://www.nejm.org/doi/abs/10.1056/NEJMra012892.
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