Understanding the worldwide spread of plague – the pathogen that killed tens of millions of people during the mid-14th century Black Death in Europe – and the sporadic plague outbreaks that still affect wildlife species can help scientists predict its persistence and affects on wildlife and human health.
This is the focus of a special issue of the journal Vector-Borne and Zoonotic Diseases, which devotes its entire February issue to papers and abstracts on plague from a worldwide plague symposium held in November 2008 in Fort Collins. Supported in part by Colorado State University, the three-day meeting featured participants from nine countries on five continents.
According to Mike Antolin, Colorado State University biologist who co-wrote the lead article for the peer-reviewed journal, “the plague bacterium provides a model for translational research because it offers a wealth of available knowledge from molecular aspects of virulence to global-scale climate patterns influencing plague outbreaks, helping us link the underlying mechanisms of the infection process to large-scale patterns of pathogen transmission and epidemiology.”
Antolin co-wrote the paper with Dean E. Biggins at the U.S. Geological Survey, Fort Collins Science Center, and Pete Gober at the U.S. Fish and Wildlife Service in Pierre, S.D. Antolin also credits other partners including Patricia Stevens with the USGS Fort Collins Science Center and Kenneth L. Gage at the Centers for Disease Control and Prevention in Fort Collins among others.
“We can take detailed knowledge of how pathogenic bacteria make their living and do ecosystem-level studies,” said Antolin, whose research group focuses on how plague persists through fleas and prairie dog colonies. “In Colorado, for example, we know that plague is something that’s in our environment. As the ‘Goldilocks’ of pathogenic bacteria, it thrives during relatively cool and wet periods like we’ve recently had, so we can show that plague is much more common in prairie dogs during years like this than during hot and dry periods of drought.
“The symposium was held here because we have such an amazing team in the Fort Collins area for studying multiple facets related to persistence of this pathogen. This is in part because of because of the kind of interdisciplinary research fostered by the Infectious Disease Supercluster at Colorado State and the presence of our partners at the U.S. Geological Survey and the Centers for Disease Control.”
Plague made its first appearance in Europe from 1347-1355. Known as the “Black Death,” it killed as many as 100 million people and persisted in Europe until the late 1700s. Plague migrated to America in the early 1900s from its place of origin on the steppes and in the Himalayan foothills in central Asia. Plague still persist as a potential human health problem in the western United States, with 10 to 12 human cases a year, as the disease is now common among ground-dwelling rodents such as prairie dogs. Because of the dependence of black-footed ferrets on prairie dogs for food and shelter, plague is also an imminent threat to that critically endangered species, Antolin said.
While large-scale human pandemics like the Black Death are now unlikely, thousands of people die each year in East Africa and Madagascar – with occasional smaller outbreaks in China. Because early symptoms are flu-like while plague infections build in patients, plague often goes undiagnosed or misdiagnosed, which is a shame since plague has little antibiotic resistance, Antolin said.
“Plague sporadically appears, causes large-scale die-offs of its rodent hosts, yet manages to persist,” Antolin said. “It may go underground but then show up again, and understanding its persistence provides us with a real mystery since we don’t know exactly how natural plague reservoirs work. Also, as an introduced pathogen in North America, plague typifies the ecological, public health, and economic consequences of the modern-day spread of exotic organisms.”
The special issue can be accessed free at http://www.liebertonline.com/toc/vbz/10/1.