Today, the plague-causing bacteria are still circulating in the world. It is held at bay by sanitation measures and drug treatment.
Plague is now rare, with fewer than 15 infections annually in the United States. The number of cases outside the United States is significantly larger, but not precisely known. Plague therefore remains of scientific interest for several reasons.
The Yersinia survival strategy against the programmed death that could kill it and its host cell may offer ideas for vaccine development, Cookson said. At present, no vaccine exists against the plague. Yesinia is of concern as a potential biological warfare pathogen because it can be aerosolized and unsuspectingly breathed into the lungs. Vaccines are being sought to offer widespread public safety, as are methods for enhancing people's overall infection-fighting capacity.
Yersinia's techniques for modulating an inflammatory response also offer scientists an overarching perspective on a fundamental aspect of a variety of important diseases.
"Many medical problems stem from too much or too little inflammatory reaction," Cookson said. People who launch an insufficient inflammatory response, or whose inflammatory response is suppressed by medications, are prone to viral, bacterial and fungal infections.
"On the other hand, excessive or improperly regulated inflammatory responses are responsible for a large number of chronic conditions," Cookson said. These include vascular flare-ups leading to stroke or heart attack, and autoimmune diseases, among them lupus, juvenile diabetes, ulcerative colitis and myasthenia gravis. Severe injury also can promote life-threatening lung inflammation.
Additionally, plague isn't the only pathogen to enhance its virulence by sidestepping the inflammatory cell death program. Several other dangerous germs do the same, but in different ways.
Usually immune system clea
|Contact: Leila Gray|
University of Washington