Showing posts with label Yersin. Show all posts
Showing posts with label Yersin. Show all posts

Friday, May 25, 2012

The Black Death, Part 2 (of 4)

Hype aside, what do we know?

The Middle Ages called what was happening "The Great Pestilence."

The "Black Death" was a term coined in the 1600s to refer to the the grimness of the event.

The "Bubonic Plague" came into currency around 1885-1890 because of the swellings/bruises that resulted from infection. The Latin for bruise is "bubo, bubonis."

Yersinia pestis, isolated in the 1880s by bacteriologists Alexandre Yersin and Shibasaburo Kitasato (who were working independently; you can guess who "published first"), loves to breed in the digestive tract of the flea. Because its prolific duplication prevents the flea from being able to digest blood, the flea travels from host to host, biting furiously in an attempt to avoid starving. This causes bacteria to spill out and into the bloodstream of the mammal. Here's a pictorial view.

If you would like a more detailed graphic of how it works (and understand biochemistry more than I do), click here.

A dozen or so cases of Bubonic Plague are diagnosed and treated each year in the United States. The victims invariably (unless they exist solely for an episode of House) live in areas of poor sanitation.

Wednesday, May 23, 2012

The Black Death, Part 1 (of 4)

A timeline for the Bubonic Plague

(An incomplete list of) Breakouts of the Bubonic Plague:

540 C.E. -- Breaks out in Egypt and reaches Constantinople in 542.
1334 -- Constantinople
1345 -- Volga River Basin
1347-1351 -- Constantinople again, then Alexandria, Cyprus, Sicily; Italy; France and Germany, London; Norway, Scotland, Wales and Ireland; then Eastern Europe; then Russia

Then approximately once each decade for the next century, it appears again. Having taken the weakest among the population in the first go-round, smaller percentages of the population die each time.

1679 -- One last small outbreak in England, but the Plague strikes central Europe hard.
1711 -- Austria
1770 -- Balkans for two years
1855 -- "The Third Pandemic" begins in China and spreads throughout the world, but with greatest losses in China and India; 12,000,000 dead
1877 -- Third Pandemic hits Russia, China, India again
1889 -- Third Pandemic finally peters out
1894 -- Alexandre Yersin isolates the bacterium that causes the Bubonic Plague (called Yersinia pestis after him); Yersin realizes rats are the mode of transport. The pandemic is ended in China in 1896.

2005 -- In September, three mice infected with Bubonic Plague go missing from laboratory in New Jersey.