Plague resurfacing as a worldwide threat

Plague, the disease that devastated medieval Europe, is re-emerging worldwide and poses a growing but overlooked threat, researchers warned on Tuesday.

While it has only killed some 100 to 200 people annually
over the past 20 years, plague has appeared in new countries in
recent decades and is now shifting into Africa, Michael Begon,
an ecologist at the University of Liverpool and colleagues
said.

A bacterium known as Yersinia pestis causes bubonic plague,
known in medieval times as the Black Death when it was spread
by infected fleas, and the more dangerous pneumonic plague,
spread from one person to another through coughing or sneezing.

"Although the number of human cases of plague is relatively
low, it would be a mistake to overlook its threat to humanity,
because of the disease's inherent communicability, rapid
spread, rapid clinical course, and high mortality if left
untreated," they wrote in the journal Public Library of Science
journal PloS Medicine.

Rodents carry plague, which is virtually impossible to wipe
out and moves through the animal world as a constant threat to
humans, Begon said. Both forms can kill within days if not
treated with antibiotics.

"You can't realistically get rid of all the rodents in the
world," he said in a telephone interview. "Plague appears to be
on the increase, and for the first time there have been major
outbreaks in Africa."

Globally the World Health Organization reports about 1,000
to 3,000 plague cases each year, with most in the last five
years occurring in Madagascar, Tanzania, Mozambique, Malawi,
Uganda and the Democratic Republic of Congo. The United States
sees about 10 to 20 cases each year.

More worrying are outbreaks seem on the rise after years of
relative inactivity in the 20th century, Begon said. The most
recent large pneumonic outbreak comprised hundreds of suspected
cases in the Democratic Republic of Congo in 2006.

Bubonic plague, called the Black Death because of black
bumps that sometimes develop on victims' bodies, causes severe
vomiting and high fever. Victims of pneumonic plague have
similar symptoms but not the black bumps.

Begon and his colleagues called for more research into
better ways to prevent plague from striking areas where people
lack access to life-saving drugs and to defend against the
disease if used as a weapon.

"We should not overlook the fact that plague has been
weaponized throughout history, from catapulting corpses over
city walls, to dropping infected fleas from airplanes, to
refined modern aerosol formulation," the researchers wrote.