Anthrax

Anthrax is an infection caused by the bacterium Bacillus anthracis or Bacillus cereus biovar anthracis. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one day and two months after the infection is contracted. The skin form presents with a small blister with surrounding swelling that often turns into a painless ulcer with a black center. The inhalation form presents with fever, chest pain, and shortness of breath. The intestinal form presents with diarrhea (which may contain blood), abdominal pains, nausea, and vomiting. According to the U.S. Centers for Disease Control and Prevention, the first clinical descriptions of cutaneous anthrax were given by Maret in 1752 and Fournier in 1769. Before that, anthrax had been described only in historical accounts. The German scientist Robert Koch was the first to identify Bacillus anthracis as the bacterium that causes anthrax. Anthrax is spread by contact with the bacterium's spores, which often appear in infected animal products. Contact includes inhalation, eating, or through an area of broken skin. It does not typically spread directly between people. At risk populations include people who work with animals or animal products and military personnel. Diagnosis can be confirmed by finding antibodies or the toxin in the blood or by the culture of a sample from the infected site. The anthrax vaccine is recommended for people at high risk of infection. Immunizing animals against anthrax is recommended in areas where previous infections have occurred. A two-month course of antibiotics such as ciprofloxacin, levofloxacin and doxycycline after exposure can also prevent infection. If infection occurs, treatment is with antibiotics and possibly antitoxin. The type and number of antibiotics used depend on the type of infection. An antitoxin is recommended for those with widespread infection. A rare disease, human anthrax is most common in Africa and central and southern Asia. It occurs more regularly in Southern Europe than elsewhere on the continent and is uncommon in Northern Europe and North America. Globally, at least 2,000 cases occur a year, with about two cases a year in the United States. Skin infections represent more than 95% of cases. Without treatment the risk of death from skin anthrax is 23.7%. For intestinal infection the risk of death is 25 to 75%, while respiratory anthrax has a mortality of 50 to 80%, even with treatment. Until the 20th century, anthrax infections killed hundreds of thousands of people and animals each year. In herbivorous animals, infection occurs when they eat or breathe in the spores while grazing. Humans may become infected by killing and/or eating infected animals. Several countries and non-state groups have developed anthrax as a weapon. It has been used in biowarfare and bioterrorism since 1916. Likely delivery methods of weaponized anthrax include aerial dispersal or dispersal through livestock. In World War II, it was developed and used by the Empire of Japan's Unit 731 against China, and researched by a British plan against Nazi Germany. The Soviet, United States, and Iraqi biological weapons program developed weaponized strains. In 1975, the Biological Weapons Convention prohibited the "development, production and stockpiling" of biological weapons. It has since been used in bioterrorism, including the 2001 anthrax attacks in the United States and an incident in 1993 by the Aum Shinrikyo group in Japan.

Etymology The English name comes from anthrax (ἄνθραξ), the Greek word for coal, possibly having Egyptian etymology, because of the characteristic black skin lesions people with a cutaneous anthrax infection develop. The central black eschar surrounded by vivid red skin has long been recognised as typical of the disease. The first recorded use of the word "anthrax" in English is in a 1398 translation of Bartholomaeus Anglicus's work De proprietatibus rerum (On the Properties of Things, 1240). Anthrax was historically known by a wide variety of names, indicating its symptoms, location, and groups considered most vulnerable to infection. They include Siberian plague, Cumberland disease, charbon, splenic fever, malignant edema, woolsorter's disease and la maladie de Bradford.

Signs and symptoms

Skin

Cutaneous anthrax, also known as hide-porter's disease, is when anthrax occurs on the skin. It is the most common (>90% of cases) and least dangerous form (low mortality with treatment, 23.7% mortality without). Cutaneous anthrax presents as a boil-like skin lesion that eventually forms an ulcer with a black center (eschar). The black eschar often shows up as a large, painless, necrotic ulcer (beginning as an irritating and itchy skin lesion or blister that is dark and usually concentrated as a black dot, (somewhat resembling bread mold) at the site of infection. In general, cutaneous infections form within the site of spore penetration two to five days after exposure. Unlike bruises or most other lesions, cutaneous anthrax infections normally do not cause pain. Nearby lymph nodes may become infected, reddened, swollen, and painful. A scab forms over the lesion soon, and falls off in a few weeks. Complete recovery may take longer. Cutaneous anthrax is typically caused when B. anthracis spores enter through cuts on the skin. This form is found most commonly when humans handle infected animals and/or animal products.

Injection In December 2009, an outbreak of anthrax occurred among injecting heroin users in the Glasgow and Stirling areas of Scotland, resulting in 14 deaths. It was the first documented non-occupational human anthrax outbreak in the UK since 1960. The source of the anthrax is believed to have been dilution of the heroin with bone meal in Afghanistan. Injected anthrax may have symptoms similar to cutaneous anthrax, with the exception of black areas, and may also cause infection deep into the muscle and spread faster. This can make it harder to recognise and treat.

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