How Yersinia pestis evolved its ability to kill millions via pneumonic plague

The mere mention of the plague brings to mind the devastating “Black Death” pandemic that spread across Europe in the 1300s. Mass graves were piled high with the corpses of its millions of victims, while the disease rampaged across Europe for many decades. Yersinia pestis, the bacterium responsible for that plague pandemic, still persists in the environment among rodent and flea populations today, and human outbreaks regularly occur around the world.

 Yersinia pestis: A microscopic view on one of the world's deadliest pathogens

Discusses infections such as Yersinia pestis, how infections happen and their significance.

 Yersinia pestis: the Natural History of Plague

The Gram-negative bacterium Yersinia pestis is responsible for deadly plague, a zoonotic disease established in stable foci in the Americas, Africa, and Eurasia. Its persistence in the environment relies on the subtle balance between Y. pestis-contaminated soils, burrowing and nonburrowing mammals exhibiting variable degrees of plague susceptibility, and their associated fleas.

An Oregon teenager was just diagnosed with bubonic plague. Here's what you need to know.

The disease is caused by the bacterium Yersinia pestis, which spreads like this: Wild rodents — chipmunks, mice, squirrels — can carry the bacteria. The fleas that live around them feed on them and pick up the bacteria, spreading it to other mammals they bite, including humans. People typically get plague when they're bitten by an infected flea — which is exactly what happened in Oregon. Other, less common ways to get plague include handling infected animals or coming into contact with a patient who has a form of plague (known as "pneumonic plague") that infects the lungs. But it's important to note that most plague is spread from animal to human, not person to person.

New Evidence the Black Death Wasn’t Actually a Bubonic Plague After All

According to scientists working at Public Health England in Porton Down, for any plague to spread at such a pace it must have got into the lungs of victims who were malnourished and then been spread by coughs and sneezes. It was therefore a pneumonic plague rather than a bubonic plague. Infection was spread human to human, rather than by rat fleas that bit a sick person and then bit another victim.

People Are Still Getting the Plague. Here's What You Need to Know

More than 80% of plague cases in the U.S. are bubonic, which causes fever, headache, chills and weakness. There is a chance that people can become infected from close contact with humans who have the pneumonic plague, but it’s not common.

Plague was around for millennia before epidemics took hold – and the way people lived might be what protected them

One of civilization’s most prolific killers shadowed humans for thousands of years without their knowledge. The bacteria Yersinia pestis, which causes the plague, is thought to be responsible for up to 200 million deaths across human history — more than twice the casualties of World War II. The Y. pestis death toll comes from three widespread disease outbreaks, known as epidemics: the sixth century Justinianic Plague that ravaged the Eastern Roman Empire; the 14th century Black Death that killed somewhere between 40% and 60% of the European population; and the ongoing Third Pandemic, which began in China in the mid-19th century and currently afflicts thousands worldwide.

Stone Age Yersinia pestis genomes shed light on the early evolution, diversity, and ecology of plague

The bacterial pathogen Yersinia pestis gave rise to devastating outbreaks throughout human history, and ancient DNA evidence has shown it afflicted human populations as far back as the Neolithic.

Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics

Plague is a vector-borne disease caused by Yersinia pestis. Transmitted by fleas from rodent reservoirs, Y. pestis emerged <6000 years ago from an enteric bacterial ancestor through events of gene gain and genome reduction. It is a highly remarkable model for the understanding of pathogenic bacteria evolution, and a major concern for public health as highlighted by recent human outbreaks.

Yersinia pestis: Sequence sheds light on the plague's past

With the renewed interest in pathogenic bacteria, the organism responsible for plague and its relatives offer insight into the basis of infectivity...