Daily University Science News

An expert panel warns that botulinum toxin poses a major biological weapons threat to the public. Botulinum toxin is the cause of the disease called botulism.
The Working Group on Civilian Biodefense, a panel convened by the Center for Civilian Biodefense Studies at the Johns Hopkins School of Public Health, recommends medical and public health guidelines and policies to minimize the consequences from an attack.

The recommendation is published in the Feb. 28 issue of the Journal of the American Medical Association (JAMA).

The report's principal authors, Steven Arnon, M.D., and Robert Schechter, M.D., of the Infant Botulism Treatment and Prevention Program of the California Department of Health, worked to complete the analysis with a team of 23 national experts, which included six Johns Hopkins University faculty members. Thomas Inglesby, M.D., a researcher with the Center for Civilian Biodefense Studies and assistant professor of infectious diseases at the Johns Hopkins School of Medicine, served as the project's leader at Johns Hopkins.

"Botulinum toxin is a serious threat as a weapon, because it is extremely lethal and easy to produce. Only a very low quantity of toxin is needed to cause a life-threatening or fatal illness," says Dr. Inglesby.

Botulinum toxin comes from the bacteria Clostridium botulinum, which grows in soil. Naturally occurring botulism is usually contracted through eating contaminated foods or by absorbing the bacteria through cuts in the skin.

Botulism is a rare disease in the U.S., with fewer than 200 cases reported each year. The Hopkins Working Group believes that intentional contamination of the food supply or aerosol dissemination of the toxin is the greatest terrorism concern.

Several nations, including the former Soviet Union and Iraq, were found to have developed and stockpiled bioweapons containing botulinum toxin, despite being signatories to the Biological Weapons Convention.

And the threat is not limited to governments. The Aum Shinrikyo cult of Japan attempted to unleash an airborne form of botulinum toxin on three occasions during the early 1990s, but all of the attacks failed.

The Hopkins Working Group endorses efforts to prevent the research, development, or use of the bioweapons, but it is providing medical and public health recommendations for botulinum toxin attack in the event that prevention fails.

The toxin works by attacking the central nervous system. It blocks the release of acetylcholine, a neurotransmitter that acts between cells. Without acetylcholine, muscles are unable to contract, and paralysis results. Patients affected with botulism may require weeks or even months on mechanical ventilation to breathe. Antitoxin can reduce the severity of botulism, but the disease has to be recognized and treated early.

"Botulism is so rare that it is often misdiagnosed. Health professionals need to be aware of the symptoms and know how to report them to their local public health authorities. Rapid tests for diagnosing botulism need to be developed and made more widely available," says Dr. Inglesby.

While antitoxins are a useful treatment, supplies are limited and the current process of production is difficult. Dr. Inglesby says existing technologies could be employed to develop large reserves of human antibody therapy, but sufficient resources would need to be invested to get this process initiated.

"The development and use of such technologies not only holds hope for the treatment of botulism, but likely for other toxin-induced diseases as well," adds Dr. Inglesby.

A botulism vaccine is available, but mass immunization would eliminate the medicinal uses of the botulinum toxin. Doctors routinely use the botulinum toxin, or "botox," to treat dystonia, migraine headaches, back pain, cerebral palsy and other diseases.

Over the past two years, The Hopkins Working Group for Civilian Biodefense has published recommendations in JAMA for responding to potential terrorist use of smallpox, anthrax and plague bioweapons. Two further reports are anticipated.