The Intersection of Plague and National Parks

Plague cases in the United States over 42 years. Copyright Centers for Disease Control and Prevention.
American national parks have spectacular scenery enjoyed by hikers worldwide. It’s one way people can enjoy some of the preserved wild places in North America. Due to this intersection of humans and wild animals, a bacterium that is endemic to the southwestern United States has infected a few humans after trips to Yosemite National Park, sparking many news headlines about the plague and closure of a few camping sites for chemical treatment to reduce local flea populations. In total, this summer has seen six cases of infection and unfortunately, three deaths from the plague. Continue reading “The Intersection of Plague and National Parks”

Bubonic Plague in the Modern World

Map of Kyrgyzstan. By Kingvinvin (Own work) [CC-BY-SA-3.0 ( or GFDL (], via Wikimedia Commons
Recent reports from central Asia show that Yersinia pestis, the bacteria that causes bubonic plague, is alive and well. Usually when I am writing about Y. pestis, I am describing research that shows the bacteria was the causative agent of ancient plagues. And yet, the bubonic plague has not been eradicated from our planet and thus, will rear its ugly, diseased head. In this case, there is news from Kyrgyzstan that an adolescent male shepherd died from bubonic plague, the first diagnosis in 30 years for Kyrgyzstan. News reports offer different explanations as to how the teenager contracted the disease. Either he ate a marmot infected with Y. pestis or was bitten by fleas that harbored Y. pestis and subsequently became infected himself. However, this diagnosis was made postmortem, and at least three others who came into contact with the boy have fevers and swollen lymph nodes, symptoms of infection with the plague. Additional people including medical staff have been isolated and monitored to ensure that if anyone else is infected, the disease does not spread further.

While treatment with antibiotics can successfully cure modern cases of the plague if given within 24 hours after symptoms appear, this news from Asia reminds us that there is a reservoir of the bacteria, and it will happily move from flea (or rodent) to human if given an opportunity. It is unlikely we will experience the devastation of the Plague of Justinian or the Black Death with the availability of antibiotics and the fact this occurred in an isolated rural area, but the news from Kyrgyzstan demonstrates Y. pestis is still infecting humans and causing death. And maybe for those living in areas where Y. pestis is endemic, reconsider whether approaching or eating cute rodents is a good idea.

What Caused the Black Death?

This post was chosen as an Editor's Selection for
I was confident I knew a few things about the bubonic plague: It was caused by the bacterium Yersinia pestis, which was transmitted to humans by fleas hitching a ride on the back of traveling rats. It spread rapidly and devastated populations around the globe, and because cats, a natural predator of scurrying rodents, had been killed, rats proliferated along with their deadly, infectious cargo. However, until I read a recent PLoS ONE article, I did not realize there was still debate about whether Yersinia pestis was the infectious agent for Black Death, the disease that ravaged 14th century Europe and killed one third of its population. Continue reading “What Caused the Black Death?”