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Updated September 07, 2015.

The first time I was told I'd seen anthrax I hadn't notice it. He had a mark on his arm that was darker than his skin. It didn't really stand out.

He'd come to seen by a doctor for another reason that was much more serious. The mark didn't hurt. The edges of it were raised a bit. His other, unrelated medical problem was more pressing and immediate in its danger.

But he knew what the black mark was. He said the word.


It meant charcoal or coal in his language. I knew the word as charcoal or coal in another language, ancient Greek - Anthrax.

This was cutaneous anthrax. It can lead to death, but most cases do not. If untreated, 1 in 5 might die. With antibiotic treatment, less than 1% die from cutaneous anthrax. 

There are other types of Anthrax, depending on the exposure. Other forms are more deadly. However, cutaneous anthrax is the most common worldwide; 95%–99% of those infected with anthrax have the cutaneous form.

Most cases of anthrax around the world are far different than the disease reported in the media. There is the concern that anthrax spores that can persist for a long time and spread through the air as an aerosol (or easily sent through the mail) may be used as weapons. As a result, the bacteria sometimes crashes into the headlines. A US army lab likely sent live samples of anthrax to 100's of locations in the US and abroad for over 10 years until discovered in 2015. The story was even bigger in 2001 when letters that contained anthrax were received in the mail by news outlets and 2 US senators, resulting in the deaths of 5 and infecting 17 others.

 

Who gets Anthrax?

Anthrax is however a disease that can be found throughout the world, largely in agricultural areas in Central and South America, the Caribbean, Africa, parts of Asia, southern and eastern Europe. In these areas, some animals, especially farm animals like cattle, sheep, goats, antelope, and deer can become infected. Anthrax is indeed a naturally occurring bacteria found in the soil and infecting wild animals and those raised for food. In rare cases, contact with these animals or animal products can lead to human infections. Handling or butchering animals can lead to cutaneous infections; playing on drums made from hides or otherwise handling carcasses can lead to infections. 

Those most at risk are: veterinarians, butchers and farmers, drummers, lab professionals, as well as potentially the military or mail carriers in the case of bioterrorism.

In rare cases, the infection can be injected, such as through heroin intravenous drug use.

What are the types of Anthrax infections?

Different infections are caused by the same anthrax spores, but depend upon the route of transmission. 

Gastrointestinal can be caught through eating meat from an infected animal (or in very rare cases water contaminated by the bacteria). Livestock are vaccinated in the US to avoid this. Others may simply swallow what they have breathed in, such as from attending a drumming ceremony with a contaminated drum. 

It can cause causes fever, chills, swelling of neck, sore throat, pain on swallowing, difficulty speaking, nausea and vomiting especially with blood, diarrhea often with blood, abdominal pain, abdominal swelling, and headache. It is not simply a stomach infection, but instead can have prominent and dangerous neck swelling.

Mortality is 25-75%.

Inhalation is acquired through inhaling spores in the air (aerosolized) such as from anything that disrupts the spores in the animals or their hides, such as through processing wool, hides, meat, or even from a drumming ceremony with a contaminated drum.  This is the most dangerous and deadly type.

Inhalation anthrax causes fever, chills, shortness of breath, confusion, cough, nausea/vomiting, abdominal pain, headache, drenching sweats, fatigue, body aches, and chest aches. 

Those who die from it often have bloody fluid in their lungs, swelling in their brain, as well as swelling around their hear (pericardial effusion) and abdomen (ascites). Some have a rash (petechial). Lymph nodes (mediastinal) and spleen may have dead tissue and bleeding.

Mortality is 80%. Without treatment, mortality is thought to be close to 100%.

Cutaneous is acquired if spores land on the skin and enter through a cut. It causes small, possibly itchy blisters, likely bunched together. There may be a painless ulcer with a black center, with swelling around the edges, often on head, neck, arms, or hands.

Injection can be acquired from injecting anthrax-contaminated materials, such as heroin. It is much like cutaneous anthrax but the disease can spread more quickly and hence be more dangerous.

What sort of bacteria is it?

It is caused by gram positive bacteria called Bacillus anthracis. What's unusual is that it infects through spores. These spores can last a long time, even a decade, in the soil or on a animal hide and infect unexpectedly. Infections can spread when it wasn't known anthrax was around.

How is it treated?

Certain antibiotics are used. More than one may be selected because of potential concerns for resistance.

There are a wide range of antibiotics that may be used per the CDC. Treatment may be with levofloxacin, moxifloxacin, or ciprofloxacin. Carbapenems may be used as well an antibiotics that reduce, hopefully, spore production like linezolid or clincamycin. Chloramphenicol can work as well. Doxycycline is sometimes used.

Some will require intubation and ventilation to allow them to breathe with the help of a machine. Many will need help from medications to keep their blood pressure from being too low.

Steroids are recommended by the CDC for those who are very sick (shock refractory to pressors), history of steroid use, swelling especially of head or neck, meningitis. 

How long does it take to get sick?

Cutaneous or injection anthrax can occur quickly within a day after exposure. Inhalation anthrax can take 7 days or more, but no more than 60 days.

What if you've been exposed?

There are antibiotics - prophylaxis - that you can take just in case under your healthcare provider's supervision to reduce the chance of getting sick. This includes Ciprofloxacin, levofloxacin, and doxycycline, which are FDA approved, and other antibiotics, like moxifloxacin; amoxicillin, penicillin clindamycin. These antibiotics are usually given for 60 days with 3 shots of the vaccine.

So, there is a vaccine?

There is a vaccine but it is not available for the general public. It is available for certain at risk groups - the military, veterinarians, certain animal husbandry workers. The Anthrax Vaccine Adsorbed (AVA) or BioThraxTM does not contain Anthrax and cannot cause anthrax. This vaccine is thought to protect against inhalation and cutaneous infection though there is limited data. It was approved by the FDA for pre-exposure vaccination and has been licensed since 1970.

Livestock are vaccinated in the US.

Can I catch it from someone who is sick?

Probably not. In unusual cases, one person who has cutaneous anthrax, with likely an infectious secretion, has infected someone else. So don't touch cutaneous anthrax.

How is it tested for?

Special reference labs in the US can assist. Lab tests, if taken before antibiotics, can show the bacteria from a sputum sample, a lumbar puncture, blood draw, skin lesion sample. Antibodies in the blood can also be tested for. A chest X-Ray or Cat scan can show "mediastinal widening" that can help diagnose inhalation anthrax.