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Bubonic plague's gene map decoded

Discovery may avert use of disease as modern weapon of mass death

By JOSEPH B. VERRENGIA Associated Press

British scientists have deciphered the genetic blueprint of bubonic plague, the microbe that killed one-third of medieval Europe and could still be a frightening biological weapon in the hands of modern-day terrorists.

The gene map could offer clues to vaccines and drugs that could keep the disease in check and perhaps even neutralize its use as a weapon of mass death.

Antibiotics have all but eliminated plague as a naturally recurring killer. Worldwide, only about 2,000 cases are reported annually, including a dozen or so in the American Southwest.

But scientists warn that plague probably is triggered by a particularly crafty bacterium, Yersinia pestis. Already, it has mutated into at least one drug-resistant version since 1997.

The gene map for Y. pestis is published in today's issue of the journal Nature.

"The genome sequence we have produced contains every possible drug or vaccine target for the organism," said the leader of the research team, Julian Parkhill of the Sanger Center in Cambridge, England.

Plague was known as the Black Death in the Middle Ages because symptoms included liquefying of the organs and hemorrhaging, which caused dark splotches under the skin.

The microbe can be transmitted to humans by fleas that have fed on the blood of an infected rat. It also is spread in airborne droplets when infected people cough. Both can be treated with antibiotics, but the airborne version develops so rapidly that it is almost always fatal within a few days.

"These properties make Y. pestis one of the most feared agents of biological warfare or bioterrorism," said microbiologist Stewart Cole of the Pasteur Institute in Paris. "The information provided by the genome sequence should be applied to ensure that plague does not re-emerge, and that one of the potential weapons of bioterrorism can be neutralized."

Normally, a gene map for an all-but-vanquished disease would interest only microbiologists and medical historians. But fears of biological warfare have increased since the Sept. 11 attacks.

The U.S. government grounded crop-dusting airplanes for several days after the attacks. Spreading plague bacteria in the air could mimic the effects of the inhaled version of the disease.

Biological agents can be unstable and have been difficult to "weaponize." During the Cold War, U.S. and Soviet laboratories assigned thousands of researchers to put plague and other biological agents in aerosol form.

Stocks of Y. pestis are kept in several microbe banks around the world. In 1997, an Ohio man pleaded guilty to illegally obtaining plague germs from a Maryland commercial laboratory.

Like most genetic discoveries, the new plague gene map is widely available to scientists. Officials said it would not be helpful to terrorists.

"The problems that they would need to overcome, such as large-scale growth and dispersal, would not be assisted by the sort of molecular information we have produced," Parkhill said.

-- Anonymous, October 04, 2001

Answers

Been reading up on pandemics recently.

Three versions of plague - bubonic (zoonotic, spread by fleas), and septicaemic and pneumonic (spread by human contact). Apparently there was some success vaccinating U.S. GIs in Vietnam, but the vaccine didn't work on the indigenous Vietnamese.

-- Anonymous, October 04, 2001