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Anthrax (Greek Άνθραξ for coal) is an acute disease in humans and animals that is caused by the bacterium Bacillus anthracis and is highly lethal in some forms. Anthrax is one of only a few bacteria that can form long-lived spores. When the bacteria’s life cycle is threatened by factors such as lack of food caused by their host dying or by a change of temperature, the bacteria turn themselves into more or less dormant spores to wait for another host to continue their life cycle.
On breathing, ingesting or getting spores in a cut in the skin, a new host allows these spores to reactivate themselves and multiply in their new host very rapidly. The anthrax spores in soil are very tough and can live many decades and perhaps centuries and are known to occur on all continents except Antarctica. Anthrax most commonly occurs in wild and domestic grass-eating mammals (ruminants) who ingest or breathe in the spores while eating grass. Anthrax can also be caught by humans when they are exposed to dead infected pigs, eat tissue from infected animals, or are exposed to a high density of anthrax spores from an animal’s fur, hide, or wool. Anthrax spores can be grown outside the body and used as a biological weapon. Anthrax cannot spread directly from human to human; but anthrax spores can be transported by human clothing, shoes etc. and if a person dies of anthrax their body can be a very dangerous source of anthrax spores. The word anthrax is the Greek word for coal, the germ’s name is derived from anthrakitis, the Greek word for anthracite, in reference to the black skin lesions victims develop in a cutaneous skin infection.
Anthrax is one of the oldest recorded diseases of grazing animals such as sheep and cattle and is believed to be the Sixth Plague mentioned in the Book of Exodus in the Bible. Anthrax is also mentioned by Greek and Roman authors such as Homer (in The Iliad), Virgil (Georgics), and Hippocrates. Anthrax can also infect humans, usually as the result of coming into contact with infected animal hides, fur, wool (“Woolsorter’s disease”), leather or contaminated soil. Anthrax (“siberian ulcer”) is now fairly rare (a few to no cases per year in the developed world) in humans although it still occasionally occurs in ruminants, such as cattle, sheep, goats, camels, wild buffalo, and antelopes.
Bacillus anthracis bacteria spores are soil-borne and because of their long lifetime they are still present globally and at animal burial sites of anthrax-killed animals for many decades; spores have been known to have reinfected animals over 70 years after burial sites of anthrax-infected animals were disturbed.
Before the last century anthrax infections were a source of many thousands of dead animals and thousands of people dying each year in Europe, Asia and North America. French scientist Louis Pasteur developed the first effective vaccine for anthrax in 1881. Thanks to over a century of animal vaccination programs, sterilization of raw animal waste materials and anthrax eradication programs in North America, Australia, New Zealand, Russia, Europe and parts of Africa and Asia anthrax infection is now rare in domestic animals with normally only a few dozen cases reported every year. Anthrax is even rarer in dogs and cats where there was only one documented case in the USA in the last 15 years. Anthrax outbreaks do occur in a few wild animal populations with some regularity. The disease is more common in developing countries without widespread veterinary or human public health programs.
There are 89 known strains of anthrax, the most widely recognized being the virulent Ames strain used in the 2001 anthrax attacks in the United States. The Ames strain is extremely dangerous, though not quite as virulent as the Vollum strain which was successfully developed as a biological weapon during the Second World War, but never used. The Vollum (also incorrectly referred to as Vellum) strain was isolated in 1935 from a cow in Oxfordshire, UK. This is the same strain that was used during the Gruinard bioweapons trials. A variation of Vollum known as “Vollum 1B” was used during the 1960s in the US and UK bioweapon programs. Vollum 1B was isolated from William A. Boyles, a 46-year-old USAMRIID scientist who died in 1951 after being accidentally infected with the Vollum strain. The Sterne strain, named after a South African researcher, is an attenuated strain used as a vaccine.
For more detailed Anthrax information see the Anthrax wiki on Wikipedia.
