Anthrax is caused by a bacterium, Bacillus anthracis, which is a Gram-positive, spore-forming, blunt-ended bacillus that shows up either singly or in pairs. It is fairly large, taking about 20,000 spores placed in a row to make an inch. When the bacillus is cultured in the lab, it can easily be confused with other members of the genus Bacillus. The virulent strains – ones able to produce deadly toxins – possess an unusual capsule composed of D-glutamic acid that protects it from phagocytosis by host cells. The spores are highly resistant to drying and can remain viable on animal products and soil for years. People can contract the microorganism from animals, but not from other people and, because of this, it is referred to as a zoonotic disease.
Other members of the genus Bacillus are able to produce disease in humans, although, not as severe as B. antracis. These diseases are more common in the US, causing serious illnesses. In the immune-compromised individual, B. subtilus may produce endophthalmitis (an inflammation or infection inside the eyeball). B. cereus is a common cause of gastroenteritis as a result of eating improperly stored cooked rice.
Anthrax spores enter the body either through skin abrasions (cutaneous anthrax), inhalation (pulmonary anthrax), or ingestion (intestinal anthrax). Illness usually strikes within two to ten days after exposure, but can be as long as six or seven weeks. Rapid diagnosis is vital as death can occur 24-72 hours after onset of symptoms.
Cutaneous anthrax is contracted when spores enter the skin tissues through abrasions or lesions. A local lesion forms at the site of entrance and rarely contains pus, but it does become swollen and bloody looking. Later, a black scab, called an ‘eschar,’ forms. If the infection remains localized, death rates are low. However, in about 5% of the cases, the infection spreads to the blood and becomes generalized, with death often the outcome.
Pulmonary anthrax results when spores are inhaled. It is seen most often in those who handle contaminated animal products. Once the spores reach the lungs, the immune system takes action. Onset is sudden, with high fever and respiratory distress. Pulmonary microphages envelop the spores but cannot digest the coating, so instead of killing it, it ends up escorting the bacteria through the bloodstream via lymph vessels to nodes just behind the breastbone (mediastinum). For some, this signals the genetic code to begin immediately while, for others, it may take days or weeks to kick in. The genetic code begins with a DNA program that spews out toxins. Early symptoms are a developing fever and a dry cough. Sometimes, there are shortness of breath and chest pain, which are typical of most impending upper respiratory infections. Pneumonia develops quickly, followed by sepsis and, in many cases, death is almost certain.
Intestinal anthrax results when spores are eaten. They often appear on infected meat, causing severe enteritis with high mortality rates. This form is very rare, however.
Alarm is rarely noted in the beginning of an anthrax infection because it starts out like any other mild illness. Thus, the standard methods of treatment for a “cold” are usually implemented. Some victims even appear to recover just before the sudden and rapid deterioration into serious illness. When X-rays show no pneumonia, still there is no alarm, but if the mediastinum were to be checked, it would reveal a widening, caused by the immense growth of the bacteria. The rapid deterioration in health consists of an agonizing shutdown of the respiratory system, including shortness of breath, high fever, and cyanosis (turning blue). Death is inevitable if the proper diagnosis is not made very early. Antibiotics cannot help after symptoms begin to appear.
Anthrax spores have been around for milleniums. Transmission of anthrax occurs among animals, usually as a result from ingesting contaminated feed. During the mid-19th century in England and Germany, anthrax was called the ‘woolsorter’s disease’ and ‘ragpicker’s disease’ because workers handling fibers and hides were more susceptible to the infection. Spores can remain viable for more than thirty years in a pasture. Recently, anthrax spores were found in the base-camp used by Scott when he went to Antarctica in 1912. It is believed that the spores were transferred there by the Manchurian ponies and Himalayan mules Scott took with him. Anthrax is known to have been an epidemic in those regions, and it is speculated that one of Scott’s men may have actually died from the disease.
The first North American cases of anthrax were documented in the early 1700s. In 1881, Louis Pasteur successfully produced a vaccine; and, in the 1920s, laws were enacted that required the testing of shaving brushes because they were often made of horsehair or pig bristles. The largest outbreak of anthrax occurred in 1957 when nine employees of a goat-hair processing plant became ill after handling a contaminated shipment from Pakistan. In the 1970s, cases were traced to souvenir drums from Haiti that had been made from goatskins. Today, gas sterilization or radiation is used to decontaminate imported hides, wool, and related animal products. Even more recently, anthrax spores appeared in various parts of the United States following the September 11, 2001, terrorist attacks.
When spores are inhaled into the lungs, mortality approaches 100%. Because of this, anthrax can be used as a biological weapon. The US Defense Department estimates that about half of all people who inhale between eight and ten thousand spores would die. An outbreak of anthrax in Russia in 1979 raised concern. It was speculated that it was an experiment gone wrong rather than the stated ‘natural’ occurrence that killed 66 out of the 77 cases. In 1992, Boris Yelsin finally admitted that it had a military cause, and was confirmed in 1994 when independent Russian and American experts determined the origin was a military lab. It is still not confirmed whether it was an accident or not.
It has long been known that there are not enough antibiotics or vaccines available for even a fraction of the population in any country should there be an epidemic. It takes weeks for the pharmaceutical companies to manufacture them. Treatment, therefore, is limited to penicillin or a broad spectrum antibiotic. Vaccines are also available for humans and animals. Antibiotics are more effective if given with the vaccine. It should be noted that black market supplies explode in price during such times as these when panic is fresh.
