Little more than a month after the Sept. 11, 2001 terrorist strikes, the nation was shaken by a new wave of attacks. Five people died--and 17 more people were sickened by--anthrax (an acute infectious disease caused by the spore-forming bacterium) sent to unwitting residents, reporters and government officials. Nearly seven years later, a microbiologist has died of an apparent drug overdose as prosecutors prepared to charge him in connection with the mailings.

Bruce Ivins, 62, who for the past 18 years worked at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), a federal biodefense research laboratory Fort Detrick in Maryland, died Tuesday at Frederick Memorial Hospital after ingesting massive amounts of prescription Tylenol with codeine. The Washington Post reports that the feds had alerted him that they planned to charge him with bioterrorism and were considering whether to seek the death penalty in the event of a conviction.

Ivins's death comes about a month after the feds forked over $5.82 million to scientist Steven Hatfill, 54, who worked with Ivins at Fort Detrick, to settle a lawsuit that he filed against former Attorney General John Ashcroft and other Justice Department officials for publicly naming him as a "person of interest" in their anthrax investigation, according to the Los Angeles Times.

Ivins, who analyzed samples from the attacks for the FBI, became a prime suspect when law enforcement agents came up dry in attempts to link Hatfield to the crimes. In addition to claiming lives, the scare also interrupted mail service, caused the evacuation of government buildings, and prompted congressional members and aides near and in offices targeted to take the powerful antibiotic ciprofloxacin (better known as cipro)--which may has a long list of possible side effects--as a precaution in case of accidental exposure to the lethal white powder. 

To avoid leaks to the press (which occurred during the Hatfill probe), the FBI required that Ivin's colleagues at USAMRIID sign confidentiality agreements when interviewed by agents as part of the investigation, the L.A. Times reported.

Investigators first questioned USAMRIID scientists in December 2001. The Times reports that Ivins, employed as a civilian at Fort Detrick, attracted the Army's attention because of anthrax contamination in his lab that he initially failed to report.

The "Amerithrax" investigation (as the FBI calls it) is one of the most complex and comprehensive ever conducted by law enforcement, the FBI said in a statement released Friday. Over the past seven years, the Amerithrax Task Force, comprised of 17 FBI special agents and 10 U.S. postal inspectors, has executed about 75 searches and conducted more than 9,100 interviews in pursuit of the perpetrator of these attacks.

Among recipients of anthrax-laced mailings: then-Sen. Thomas A. Daschle (D-S.D.), Sen. Patrick Leahy (D-Vt.), TV network news outlets in New York and American Media, Inc., the parent company of the National Enquirer among others, in Boca Raton, Fla. The dead included two Washington, D.C. postal workers, a photographer for American Media in Florida, a New York hospital worker and an elderly Connecticut woman.

Antibiotics can kill the anthrax bacterium, but time is of the essence. If the drug is not administered quickly enough, the toxin secreted by the bug may reach lethal levels in the blood before the medicine can kill it. Bacillus anthracis not only secretes toxins that irreversibly damage immune system cells but also forms a protective capsule and avoid detection as it spreads. Because the vaccine available at the time of the attacks targeted only part of the toxin released by Bacillus anthracis, scientists have been investigating new approaches.

Emergent BioSolutions, Inc. in Rockville, Md. announced last week that it has secured two grants totaling over $4.5 million from The National Institute of Allergy and Infectious Diseases (NIAID) to fund the continued development of the company's Recombinant Botulinum Vaccine (rBOT) and Next Generation Anthrax Vaccine (NGAV) vaccine candidates. The company's BioThrax (Anthrax Vaccine Adsorbed), is the only vaccine approved by the U.S. Food and Drug Administration for the prevention of anthrax infection.

A report published in 2003 by the Proceedings of the National Academy of Sciences indicated that the U.S. was unprepared to deal with a widescale anthrax attack and that if a major city were hit it could lead to as many as 123,000 deaths. Concern over anthrax, or some other biological agent, being used as part of a terrorist attack led some to call for the government to install sensors that raised an alarm soon after spores appeared in the environment.