WHAT CAUSES ANTHRAX?

Anthrax is caused by the organism Bacillus anthracis. In some parts of the world, this can be found in cattle or other hoofed mammals. It is infrequent in western Europe and the US, and is more likely to be found in animals in south and central America, south and east Europe, Asia and Africa. This bacteria can form spores which can either be eaten in contaminated meat, breathed in, or simply infect the skin directly through human to animal contact.

WHAT ARE THE SYMPTOMS OF ANTHRAX?

There are three types of anthrax, depending on where the infectious spore has arrived on the patient The first, cutaneous anthrax, is the least serious of the three, and produces a skin lesion, which is rarely painful. However, if left untreated, the infection can spread and cause blood poisoning, which is fatal in one in 20 cases.

The second type is intestinal anthrax, caused by the consumption of contaminated meat. This produces severe food-poisoning type symptoms, leading to fever and blood poisoning. It is frequently fatal.

The third is respiratory (or inhalation) anthrax which happens when spores are breathed in by the patient and lodge in the lung (see figure). Symptoms of this disease start out as similar to simple flu, but respiratory symptoms rapidly worsen and the patient usually goes into some kind of shock between two and six days later. Again, this is frequently fatal.

IS ANTHRAX CONTAGIOUS?

No. It is an infectious disease, but not contagious. An infectious illness spreads and grows within the body, a contagious disease spreads from person to person. Because the disease is not contagious, only those directly exposed to the spores have any chance of falling ill.

HOW DEADLY IS ANTHRAX?

A 1993 report estimated that releasing a cloud of 100 kg of spores upwind of Washington DC could cause between 130,000 and 3,000,000 deaths.

DOES EXPOSURE TO ANTHRAX ALWAYS MEAN INFECTION?

Being exposed to anthrax spores does not necessarily mean that you will develop an infection. Many of the spores are dormant, and pose no threat. In addition, infection will only result if sufficient numbers of the spores germinate and release harmful bacteria in sufficient quantities. Small amounts of the bacteria can be killed off by the body's immune system. It is estimated that 10,000 spores are needed to cause infection. Once anthrax spores have lodged in the lung and caused an infection, nine out of 10 patients die.

CAN ANTHRAX BE TREATED?

Giving antibiotics to anthrax patients can cure the disease, particularly the cutaneous variety. The antibiotic of choice is ciprofloxacin, or Cipro. However, unless it is given swiftly after intestinal or respiratory infection, the chances of cure are greatly reduced.

IS THERE A VACCINE?

There is a vaccine against anthrax, but this is not recommended except for those at high risk, such as meat industry workers and laboratory scientists handling the disease.

IS ANTHRAX EASY TO MAKE?

Culturing large quantities of anthrax spores is a complicated task, but certainly not beyond the capacity of many nations. During the 1990s, it was suggested that at least 17 nations had some biological weapons capacity.

WHAT IS "WEAPONS-GRADE" ANTHRAX?

To make an "effective" bio-weapon, the anthrax has to be prepared in a way that will make it hang in the air - an aerosol - in sufficient quantities that it can be breathed in and cause disease.

Loading it on to a fine powder could do this. The powder itself might be treated so that it is electrically neutral, does not stick to surfaces and stays airborne for longer. A strain that is more resistant, or has been altered to be more resistant, to treatment from antibiotics will also have more damaging effects.

A preparation of the anthrax that met these criteria could be described as "weapons-grade" and its use could indicate state involvement in any attack because of the necessary expertise and funding that would be involved.

Source: BBC News, October 15, 19, 2001.