SCI-TECH BRIEFING

An occasional series on science and technology

New weapons against anthrax

by Andrij Wowk and Ihor Magun, M.D.

In the wake of the recent anthrax contamination cases in the U.S. mail research into new methods of protection against biological and chemical weapons has become an important part of the global war on terrorism - one involving a large team of scientists, engineers and medical experts throughout the world.

According to the U.S. Defense Department's annual report to Congress, at least 10 countries have the capability of producing and disseminating biological weapons such as anthrax. And, for many hostile regimes around the globe, anthrax has long been a "weapon of choice," according to Theodore Prociv, CEO of Versar, Inc., a Washington, D.C.-area-based engineering and environmental services firm heavily involved in anthrax testing and decontamination.

Dr. Prociv, 54, became Versar's CEO two and a half years ago, after spending 15 years in industry and five and a half years, as the Pentagon's main specialist on biological and chemical weapon demilitarization in the Clinton administration's Department of Defense. He has also worked closely with officials in both the Ukrainian and Russian governments on the elimination of chemical and biological weapons.

"When I was at the Pentagon, we had a lot of concern about anthrax being used as a biological weapon," noted Dr. Prociv, who grew up among the Ukrainian-American community in New York City and finished a Ph.D. in chemistry there. Today, his role at Versar includes developing better methods for anthrax detection and decontamination, and products for protecting humans against such potential attacks.

The nature of anthrax

Anthrax is a disease caused by Bacillus anthracis, a gram-positive, spore-forming bacterium. Anthrax spores can exist dormant for decades, but when exposed to the appropriate environment, they can germinate and cause the disease. There are three possible ways to acquire anthrax: skin contact, inhalation and ingestion of anthrax-infected undercooked meat. Of note, human-to-human transmission of anthrax infection has not been shown to occur.

Skin or cutaneous anthrax starts about five days after exposure to anthrax spores. The skin lesion presents as a non-painful elevation on the skin, which then becomes a blister with a central black crust. This black crust actually gives the disease its name, since anthrax is a Greek word that means coal. Cutaneous anthrax is curable.

The human health threat posed by anthrax is not new. For over a century, individuals working with livestock or processing animal products were routinely exposed to anthrax just in the course of a normal working day. Cases of anthrax, in those circumstances, were rare and usually caused as the result of contact with infected animals. In Ukraine, where anthrax is commonly known as "sybirka," the disease is believed to have existed even before the appearance of humans (The Ukrainian Observer, February 13.)

There are two recorded events in world history in which anthrax was used as a potential weapon. The first occurred during World War II, when anthrax was used by the Japanese government. The second occurred in 1979, when anthrax spores were inadvertently released in the Ural mountain region of Soviet Russia. This resulted in 77 confirmed infected individuals, with 66 deaths.

Technical approaches

In autumn 2001, Versar was hired to decontaminate the Hart Senate Office Building in Washington, where anthrax spores were discovered as a result of contaminated mail. The company has also tested some 200 other office buildings throughout the U.S. for the presence of anthrax, including the corporate offices of The New York Times and CNN, according to Dr. Prociv. The technology for anthrax screening and decontamination is continuously evolving, he noted.

For example, chlorine dioxide gas was used to decontaminate the Hart Building, which Dr. Prociv says is now considered a "sloppy" decontamination method. Versar currently uses hydrogen peroxide, a "more-benign" agent he said, which has the added benefit of killing molds that grow within buildings. Researchers at the University of Florida are also experimenting with a common pesticide, methyl bromide, which has been found to effectively kill anthrax more safely and cheaply than chlorine dioxide (The Star Ledger, April 29).

As a preventive measure, the floors and walls of some buildings can be coated with an epoxy compound - known as "hardening" a facility - to make these surfaces more easily cleaned if anthrax is detected, Dr. Prociv said. Methods of personal protection against biological or chemical agents also are evolving. For example, Versar has developed and will soon release a new type of gas mask that seals at the neck, and is thus more effective than existing gas masks, which must be individually fitted to the wearer. The new type of mask is also expected to cost only one-third as much as current models.

Developing new instruments that can quickly and accurately screen for the presence of anthrax spores is also a key area of research. One such instrument is an improved anthrax detector which has been developed by Versar. The device, a modified version of a medical instrument known as a flow cytometer, is much more sensitive to anthrax than other existing instruments, according to Dr. Prociv.

According to the March issue of Scientific American, researchers at the Massachusetts Institute of Technology have developed a device known as The Canary, which detects the presence of anthrax using sensors which consist of living cells - B cells of the immune system - that have been genetically altered to emit light when their calcium levels change. And Cepheid, a California-based company, has developed a DNA-based anthrax detector known as the GeneExpert system, which extracts DNA samples from micro-organisms and analyzes them to determine if the anthrax bacterium is present.

Medical approaches

On the medical front, researchers are investigating possible new treatments for those who have already been infected by anthrax, as well as new vaccines against it. Anthrax infection is positively diagnosed through a blood test, but treatment with antibiotics is usually started as soon as infection is suspected, based on observed symptoms or an individual's potential exposure to the anthrax bacteria.

Although antibiotics help the body to fight the multiplication of the anthrax bacteria, they do not prevent damage to the body caused by the toxin that the bacteria produce. Therefore, researchers are focusing on developing new therapeutic drugs for those infected with anthrax, according to Scientific American. Such drugs are generally known as antitoxins, since they would be aimed at neutralizing the anthrax toxin in infected individuals. Antitoxins would probably be used in combination with antibiotics, in the same way that cocktails of antiviral drugs are used for HIV patients.

Researchers at Rutgers University in New Jersey are exploring another possible weapon against anthrax infection: viruses. As an alternative to antibiotics, viruses can be designed to target and destroy only specific bacteria, such as anthrax. Antibiotics kill both good and bad micro-organisms within an individual, and some bacteria can develop resistance to them.

The development of new and improved vaccines against anthrax is also being pursued by medical researchers. The only anthrax vaccine approved for human use in the U.S. is known as AVA (anthrax vaccine adsorbed) and consists of anthrax toxin molecules that have been treated to prevent them from making people ill. Although this vaccine is given to soldiers and some civilians, it is not practical for providing immunity to anthrax in a short amount of time. Some researchers are looking into the possibility of producing a more powerful, faster-acting vaccine based on DNA technology. Some such vaccines may have antitoxin effects, as well as the ability to stimulate immunity to anthrax.

Research into anthrax vaccines for animals is also being done in Ukraine. Veterinary anthrax vaccines, including one known as "Antrakal," are currently being produced at a facility in the city of Kherson (The Ukrainian Observer, February 13).

Medical information on anthrax is rapidly evolving, and readers are encouraged to visit the website of the Centers of Disease Control (www.cdc.gov) for the latest information and advice about this topic.

Andrij Wowk is president of the Ukrainian Engineers' Society of America. Ihor Magun is a board certified physician in internal medicine.

Copyright © The Ukrainian Weekly, June 9, 2002, No. 23, Vol. LXX

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