Scientists in Germany say the black rat is back, in higher numbers than ever before.They say Rattus rattus is now widespread even in areas where it was thought to be extinct. The black rat, also known as the ship?s rat, spread bubonic plague through Europe in medieval times.

Researchers from the Zoological Institute at Cologne University say the black rat population in Germany has been underestimated because damage is automatically blamed on the more aggressive, and more common, brown rat. The plague in Europe finally ended when brown rats, which do not carry plague, drove out the black rats.
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With the world facing biowarfare after the recent Anthrax cases in Florida, scientists say they have mapped all the genes in the plague bacterium which could speed up research into vaccines and treatments. Along with smallpox and anthrax, the bubonic plague is one of the most feared potential biological weapons.

A 30 member team of scientists at Britain?s Wellcome Trust Sanger Center in Cambridge has discovered how the bacterium turned itself from a irritating stomach bug into the Black Death that killed 200 million people, or a third of Europe, in the 14th century. They have sequenced the 4,012 genes of the plague bacterium, or Yersinia pestis, and believe it evolved into such a lethal agent by gaining and losing bits of DNA around 1,500 years ago.
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Pathogens from the same plague that wiped out 30 percent of the world’s population in the 14th century have been found near Lake Meredith in Texas. One out of six flea samples taken from a nearby campground showed the plaguepathogen. The samples were screened at the Centers for Disease Control in Fort Collins, Colorado.

Suspicion was aroused when a nearby prairie dog town was completely wiped out. Chief Ranger Bill Briggs said a maintenance worker noticed the absence of the normal activity of the 50-100 prairie dogs. After digging at thesite, no carcasses or signs of the rodents could be found.
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