Latest news with #YersiniaPestis
The Independent
11-07-2025
- Health
- The Independent
What we know about the US resident who died from the plague
A person in Northern Arizona has died from the plague, confirmed by health officials after an autopsy revealed the presence of Yersinia pestis, the bacterium responsible for plague. The victim was taken to hospital with severe symptoms and died the same day. This fatality occurred amid a significant die-off of prairie dogs near Flagstaff, prompting Coconino County officials to investigate the link and collect fleas for testing. Plague remains rare in modern America, with an average of seven human cases annually, primarily affecting rural areas of the Western U.S. Symptoms include fever, chills, and swollen lymph nodes, but prompt antibiotic treatment, ideally within 24 hours, offers a high survival rate for bubonic plague. Public health officials urge residents to report sick or dead rodents, use flea control on pets, and seek immediate medical care if symptoms develop after potential exposure.
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The Independent
11-07-2025
- Health
- The Independent
Arizona resident dies from the plague less than 24 hours after showing symptoms
A person has died from the plague in Northern Arizona, health officials confirmed Thursday. The victim was rushed to Flagstaff Medical Center, showing severe symptoms, and died the same day. An autopsy revealed Yersinia pestis, the bacterium responsible for plague, was found. No further details about the patient or their identity have been revealed. This case comes amid a recent prairie dog die-off northeast of Flagstaff, a classic red flag for plague activity since these rodents often carry infected fleas. Coconino County officials are investigating an unknown number of prairie dog deaths linked to plague. They are working with a property owner to collect fleas for testing. The plague remains rare in modern America, with the Centers for Disease Control reporting an average of seven human cases annually, the majority of which occur in rural areas of the Western U.S., including northern Arizona and parts of New Mexico and Colorado. Plague occurs in three forms, bubonic, septicemic and pneumonic, depending on whether the infection hits the lymph nodes, bloodstream or lungs. Most US cases are bubonic, typically spread via flea bites from infected rodents. According to the Cleveland Clinic, worldwide plague cases number around 1,000 to 2,000 per year, with the U.S. reporting about seven annually. Symptoms often begin within a week of infection and may include fever, chills, swollen lymph nodes, nausea and weakness. If treated promptly, ideally within 24 hours of symptoms, antibiotics are effective, and bubonic plague has a survival rate exceeding 90 percent. Without treatment, however, mortality rates can skyrocket. Public health officials urge residents to report sick or dead prairie dogs and other rodents, use flea control products on pets, and seek immediate medical care if symptoms like fever or swollen glands develop after possible exposure.
Gizmodo
05-06-2025
- Health
- Gizmodo
This Genetic ‘Trick' Helped the Black Death Linger for Centuries
Yersinia pestis—the bacterium that causes the bubonic plague—experienced a genetic tweak that allowed rodents to live longer after they were infected, according to a new study. This alteration may have prolonged two significant plague pandemics, including the deadliest event in human history: the Black Death. Researchers at the Institut Pasteur in France and McMaster University in Canada studied hundreds of ancient Y. pestis DNA samples to investigate a gene called 'pla.' Their study, published May 29 in the journal Science, identified a decrease in repetitions of the pla gene in the Y. pestis genome during the later stages of both the first and second major plague pandemics. The researchers believe these pla depletions ultimately allowed these pandemics to last longer. The first plague pandemic, known as the Plague of Justinian, struck the Mediterranean basin during the sixth century and caused tens of millions of deaths over the course of two centuries. The second emerged when the Black Death broke out in 1347, killing an estimated 30% to 50% of Europe's population in just six years. But this was just the beginning. Like the first pandemic, this plague continued to reemerge for centuries, lasting more than 500 years. This newly discovered evolution of the pla gene offers more insight into how these plagues persisted for so long. The pla gene appears many times in the Y. pestis' genome and plays a crucial role in its virulence by allowing it to infect the lymph nodes before traveling to the rest of the body, according to an Institut Pasteur statement. This causes rapid septicemia—or blood poisoning—and quickly kills the victim. Therefore, a lack of this gene in Y. pestis strains from the first and second major pandemics likely made the bacterium less virulent, the researchers suggest. To test that hypothesis, they infected mice with three preserved strains of Y. pestis from the third major pandemic that also had fewer repetitions of pla. 'These three samples enabled us to analyze the biological impact of these pla gene deletions,' said co-author Javier Pizarro-Cerdá, director of the Yersinia Research Unit at the Institut Pasteur, according to the statement. Through their mouse model, Pizarro-Cerdá and his colleagues found that the pla depletion resulted in a 20% decrease in victim mortality. What's more, it allowed infected rodents to live significantly longer. Based on these findings, the researchers concluded that rats infected with pla-depleted Y. pestis strains may have been more effective disease vectors, as they had more time to spread the plague far and wide before they died. Rodents—particularly rats—played a critical role in spreading the bubonic plague to humans. People most commonly contract this disease via infected flea bites, and fleas typically contract it when they feed on infected rodents. Thus, an increase in the lifespans of sickened rodents would have provided greater opportunity for fleas to bite them, become infected, and then bite humans. 'Ours is one of the first research studies to directly examine changes in an ancient pathogen, one we still see today, in an attempt to understand what drives the virulence, persistence, and eventual extinction of pandemics,' said co-lead author Hendrik Poinar, director of the McMaster Ancient DNA Centre and holder of the Michael G. DeGroote Chair in Genetic Anthropology, according to the statement. Today, the bubonic plague is considered a rare disease, though a small number of cases still emerge in western North America, Africa, Asia, and South America, according to the Cleveland Clinic. While this research provides valuable insight into the evolutionary history of Y. pestis and the world-altering pandemics it caused, it can also serve as a model for better understanding how deadly diseases emerge and spread, according to the researchers.
CTV News
03-06-2025
- General
- CTV News
One of the world's most notorious pathogens has survived for centuries. Scientists say they now know why
Researchers have announced that they've discovered what allowed the bacterium Yersinia pestis, the cause of the Black Death, to keep its hosts alive longer. (BSIP/Universalvia CNN Newsource) One of the bleakest periods in medieval Europe was the plague pandemic known as the Black Death, which killed at least 25 million people in just five years. But the disease didn't stop there. The plague adapted to keep its hosts alive longer, so it could spread farther and keep infecting people for centuries, and researchers now say they've discovered how. The disease is caused by the bacterium Yersinia pestis, which has been circulating among human populations for at least 5,000 years. The pathogen has fueled three major plague pandemics since the first century AD, and though its deadliest years appear to be behind us, plague hasn't disappeared. Cases still occur a few times a year in Asia, South America and the United States and more commonly in parts of Africa, according to the Cleveland Clinic, and can be treated with antibiotics. Scientists are still searching for answers about how Y. pestis evolved and dispersed, but recent analysis of ancient and modern Y. pestis samples revealed how plague managed to persist among humans for hundreds of years after pandemic waves petered out. After an initial period of high infection rates and rapid mortality — killing infected people within three days — changes to just one gene in the bacterium produced new strains that were less deadly and more transmissible, according to research published Thursday in the journal Science. Those weakened strains eventually went extinct; the dominant lineage of today's Y. pestis is the deadlier variety, the study authors reported. However, these findings about historic instances of Y. pestis adaptation could provide important clues to help scientists and physicians manage modern plague outbreaks. Trio of outbreaks Plague's most common form is bubonic plague, which causes painful swelling in lymph nodes and spreads among people through bites from fleas hitchhiking on infected rats. An outbreak of bubonic plague from 1347 to 1352 in Europe famously killed about 30% to 50% of the continent's population. But the earliest known bubonic plague outbreak — the Plague of Justinian — took hold in the Mediterranean Basin and lasted from AD 541 to AD 544. Another plague outbreak emerged in China in the 1850s and sparked a major epidemic in 1894. Scientists view modern plague cases as part of this third pandemic. For the new study, scientists collected ancient samples of Y. pestis from human remains dating back to about 100 years after the appearance of the first and second plague pandemics, sampling remains from Denmark, Europe and Russia. After reconstructing the genomes of these plague strains, they compared them with older, ancient strains that dated back to the start of plague pandemics. The researchers also examined more than 2,700 genomes of modern plague samples from Asia, Africa, and North and South America. One of the study coauthors, Jennifer Klunk, is a product scientist at Daciel Arbor Biosciences, a biotechnology company in Michigan that provided synthetically created molecules for the experiments, but there was no financial gain associated with the research. The researchers found that their newly reconstructed genomes from 100 years into the first two plague pandemics had fewer copies of a gene called pla, which has been recognized for decades as one of the factors that made plague so deadly, according to the study's co-lead author Ravneet Sidhu, a doctoral student in the McMaster Ancient DNA Centre at McMaster University in Hamilton, Ont. Pla encodes an enzyme that interacts with host proteins, 'and one of the functions that it carries out is in breaking down blood clots,' Sidhu told CNN. This ability helps Y. pestis spread into the host's lymph nodes, where it replicates before attacking the rest of the body. 'Not every function of this gene is fully known,' Sidhu added. However, prior studies by other researchers linked pla to severity of illness caused by both bubonic and pneumonic plague — an airborne form of the disease that affects the lungs, she said. While the reconstructed strains showed fewer copies of the pla gene, the scientists were still uncertain whether that would directly affect how deadly the disease could be. So they tested strains of reduced-pla bubonic plague on mice, and found that survival rates for this type of plague were 10 to 20 percent higher in those experiment subjects than in mice infected with Y. pestis that had a normal amount of the pla gene. It also took the reconstructed bubonic strain about two days longer to kill its hosts. 'The paper presents a strong argument that depletion, but not total loss, of Pla (the enzyme produced by the pla gene) is part of the evolution of the plague pathogen and may help explain the decline of plague in the second pandemic commonly known as the Black Death,' said Dr. Deborah Anderson, a professor of veterinary pathobiology at the University of Missouri's College of Veterinary Medicine. Anderson, who was not involved in the new research, investigates the virulence of plague, and these findings could shed light on transmission patterns in modern cases, she told CNN in an email. 'Our laboratory studies the flea-rodent cycle and we have collaborators who conduct field research in areas that experience annual or occasional plague outbreaks in the wild,' Anderson said. 'There are nearly 300 rodent species that can transmit Yersinia pestis, and today, burrowing rodents such as prairie dogs or ground squirrels are considered key animal hosts that experience outbreaks of disease,' she added. 'After reading this paper, we will pay closer attention to Pla in the future to see if there continues to be a role for its expression in driving the explosive outbreaks of plague in the animal populations.' Yersinia pestis study Co-lead study author Ravneet Sidhu examines a human tooth at McMaster University's Ancient DNA Centre in Hamilton, Ont. (McMaster University via CNN Newsource) 'Epidemic burnout' Mathematical models suggested how this might have played out in human populations centuries ago, leading to an 'epidemic burnout' about 100 years after a bubonic plague outbreak. In a pandemic's early stages, infections were swift, and death came quickly for both rats and humans. Over time, as dense rat populations thinned out, selective pressures favored the emergence of a less deadly strain of Y. pestis, with fewer copies of the pla gene. Rat hosts infected with this new strain would have a little more time to carry the disease, potentially enabling them to infect more rats — and more people. 'They suggest a model that can be readily pursued in the laboratory that may help explain the spread of plague today in the wild,' Anderson said. These weaker strains of the disease eventually sputtered out and went extinct. In the modern samples, the researchers found just three examples of strains with reduced pla genes, from Vietnam: one from a human subject and two from black rats (Rattus rattus). 'We've been able to do this really cool interdisciplinary study between the modern and ancient data and marry these things that have been happening throughout (the plague's) long evolutionary history,' Sidhu said. 'It could be interesting to see how future researchers continue to try and bridge that gap between the modern third pandemic and those first and second ancient pandemics, to see other similarities. Because there aren't a lot of ancient pathogens that we have as much data on, as we do for Yersinia pestis.' One of the unusual features of plague pandemics is their persistence, and understanding how Y. pestis changed its infection patterns and survived over time could shed light on the adaptive patterns of modern pandemics such as Covid-19, she added. 'Even if we aren't experiencing it to the amount that we were in 2020 or 2021, the pathogen is in the background — still evolving and persisting.' By Mindy Weisberger, CNN
CNN
03-06-2025
- Health
- CNN
Gene mutation found in the bacterium behind the Black Death helped plague conquer the world, scientists say
One of the bleakest periods in medieval Europe was the plague pandemic known as the Black Death, which killed at least 25 million people in just five years. But the disease didn't stop there. The plague adapted to keep its hosts alive longer, so it could spread farther and keep infecting people for centuries, and researchers now say they've discovered how. The disease is caused by the bacterium Yersinia pestis, which has been circulating among human populations for at least 5,000 years. The pathogen has fueled three major plague pandemics since the first century AD, and though its deadliest years appear to be behind us, plague hasn't disappeared. Cases still occur a few times a year in Asia, South America and the United States and more commonly in parts of Africa, according to the Cleveland Clinic, and can be treated with antibiotics. Scientists are still searching for answers about how Y. pestis evolved and dispersed, but recent analysis of ancient and modern Y. pestis samples revealed how plague managed to persist among humans for hundreds of years after pandemic waves petered out. After an initial period of high infection rates and rapid mortality — killing infected people within three days — changes to just one gene in the bacterium produced new strains that were less deadly and more transmissible, according to research published Thursday in the journal Science. Those weakened strains eventually went extinct; the dominant lineage of today's Y. pestis is the deadlier variety, the study authors reported. However, these findings about historic instances of Y. pestis adaptation could provide important clues to help scientists and physicians manage modern plague outbreaks. Plague's most common form is bubonic plague, which causes painful swelling in lymph nodes and spreads among people through bites from fleas hitchhiking on infected rats. An outbreak of bubonic plague from 1347 to 1352 in Europe famously killed about 30% to 50% of the continent's population. But the earliest known bubonic plague outbreak — the Plague of Justinian — took hold in the Mediterranean Basin and lasted from AD 541 to AD 544. Another plague outbreak emerged in China in the 1850s and sparked a major epidemic in 1894. Scientists view modern plague cases as part of this third pandemic. For the new study, scientists collected ancient samples of Y. pestis from human remains dating back to about 100 years after the appearance of the first and second plague pandemics, sampling remains from Denmark, Europe and Russia. After reconstructing the genomes of these plague strains, they compared them with older, ancient strains that dated back to the start of plague pandemics. The researchers also examined more than 2,700 genomes of modern plague samples from Asia, Africa, and North and South America. One of the study coauthors, Jennifer Klunk, is a product scientist at Daciel Arbor Biosciences, a biotechnology company in Michigan that provided synthetically created molecules for the experiments, but there was no financial gain associated with the research. The researchers found that their newly reconstructed genomes from 100 years into the first two plague pandemics had fewer copies of a gene called pla, which has been recognized for decades as one of the factors that made plague so deadly, according to the study's co-lead author Ravneet Sidhu, a doctoral student in the McMaster Ancient DNA Centre at McMaster University in Ontario, Canada. Pla encodes an enzyme that interacts with host proteins, 'and one of the functions that it carries out is in breaking down blood clots,' Sidhu told CNN. This ability helps Y. pestis spread into the host's lymph nodes, where it replicates before attacking the rest of the body. 'Not every function of this gene is fully known,' Sidhu added. However, prior studies by other researchers linked pla to severity of illness caused by both bubonic and pneumonic plague — an airborne form of the disease that affects the lungs, she said. While the reconstructed strains showed fewer copies of the pla gene, the scientists were still uncertain whether that would directly affect how deadly the disease could be. So they tested strains of reduced-pla bubonic plague on mice, and found that survival rates for this type of plague were 10 to 20 percent higher in those experiment subjects than in mice infected with Y. pestis that had a normal amount of the pla gene. It also took the reconstructed bubonic strain about two days longer to kill its hosts. 'The paper presents a strong argument that depletion, but not total loss, of Pla (the enzyme produced by the pla gene) is part of the evolution of the plague pathogen and may help explain the decline of plague in the second pandemic commonly known as the Black Death,' said Dr. Deborah Anderson, a professor of veterinary pathobiology at the University of Missouri's College of Veterinary Medicine. Anderson, who was not involved in the new research, investigates the virulence of plague, and these findings could shed light on transmission patterns in modern cases, she told CNN in an email. 'Our laboratory studies the flea-rodent cycle and we have collaborators who conduct field research in areas that experience annual or occasional plague outbreaks in the wild,' Anderson said. 'There are nearly 300 rodent species that can transmit Yersinia pestis, and today, burrowing rodents such as prairie dogs or ground squirrels are considered key animal hosts that experience outbreaks of disease,' she added. 'After reading this paper, we will pay closer attention to Pla in the future to see if there continues to be a role for its expression in driving the explosive outbreaks of plague in the animal populations.' Mathematical models suggested how this might have played out in human populations centuries ago, leading to an 'epidemic burnout' about 100 years after a bubonic plague outbreak. In a pandemic's early stages, infections were swift, and death came quickly for both rats and humans. Over time, as dense rat populations thinned out, selective pressures favored the emergence of a less deadly strain of Y. pestis, with fewer copies of the pla gene. Rat hosts infected with this new strain would have a little more time to carry the disease, potentially enabling them to infect more rats — and more people. 'They suggest a model that can be readily pursued in the laboratory that may help explain the spread of plague today in the wild,' Anderson said. These weaker strains of the disease eventually sputtered out and went extinct. In the modern samples, the researchers found just three examples of strains with reduced pla genes, from Vietnam: one from a human subject and two from black rats (Rattus rattus). 'We've been able to do this really cool interdisciplinary study between the modern and ancient data and marry these things that have been happening throughout (the plague's) long evolutionary history,' Sidhu said. 'It could be interesting to see how future researchers continue to try and bridge that gap between the modern third pandemic and those first and second ancient pandemics, to see other similarities. Because there aren't a lot of ancient pathogens that we have as much data on, as we do for Yersinia pestis.' One of the unusual features of plague pandemics is their persistence, and understanding how Y. pestis changed its infection patterns and survived over time could shed light on the adaptive patterns of modern pandemics such as Covid-19, she added. 'Even if we aren't experiencing it to the amount that we were in 2020 or 2021, the pathogen is in the background — still evolving and persisting.' Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American and How It Works magazine. She is the author of 'Rise of the Zombie Bugs: The Surprising Science of Parasitic Mind Control' (Hopkins Press).
