Anthrax Antidote

Scientists believe they are a step closer to developing an antidote for the deadly weapon anthrax. The breakthrough comes as concern grows about the threat of bio-terrorism in the wake of the attacks across the world.

US researchers say they have discovered how the body responds to the anthrax toxin.

In tests on mice, some of the animals were genetically variant that made them resistant to its effects. The team, from Harvard Medical School, says this variation might boost the body's immune cells' response to the anthrax. They suggest people who carry the genetic variation might be naturally more resistant to anthrax than others, which could be used to determine who needs more urgent attention after exposure to anthrax.

The use of anthrax in a terrorist attack is so feared because it is relatively easy to spread - and is fatal in around 90% of the people it infects.

Vaccine

The Centre for Applied Microbiology and Research, at Porton Down in Salisbury, is the only place in the world that can manufacture a licensed vaccine against anthrax.

The lack of vaccine led scientists to begin work looking for an antidote to the poison.

The anthrax bacterium one of the most infectious agents known to man, spreads by spores, invading the lungs and poisoning the blood. It produces a toxin that kills white blood cells called macrophages which break down foreign bodies which invade the body.

A person develops flu-like symptoms two to three days after they are infected, followed by high fever, vomiting, joint ache, laboured breathing, internal and external bleeding, lesions and usually death.

The Harvard doctors discovered a variation in a gene called Kif1C determined how well mice could resist anthrax. Mice with the variation were more resistant to a particular aspect of the toxin.

The scientists do not yet know for certain how the gene works. When a macrophage is invaded by the anthrax toxin, the body tries to fight it off. But the process causes many of these cells to self-destruct, sending debris into the blood stream, sending the whole system into a state of shock which is ultimately fatal.

Dr. William Dietrich, a geneticist involved in the research, speculated that the gene may deal with the anthrax toxin by sending it to a part of the cell where it can be attacked more successfully and if an antidote could be developed, he said: "hopefully we would be able to stop the disease course in a patient who was unvaccinated."