New test developed for plague

Scientists working for the U.S. Army's Walter Reed Institute of Research have developed a new test for the presence of Y. pestis, the causative agent of bubonic and pneumonic plague.

The new test, according to the June 28 army report published in PLos One, can give results in as little as four hours. Existing tests can do so in the same amount of time, but the new test does not require the added step of extracting DNA and can distinguish between dormant or dead Y. pestis and living Y. pestis.

The test works by monitoring the growth of two viruses that infect bacteria, known as phages. The use of two phages works to increase the sensitivity and specificity of the results. The method used is known as a quantitative real-time polymerase chain reaction assay used for indirect identification.

According to the Centers for Disease Control and the army's report, Y. pestis, a member of the Enterobacteriaceae family, is considered a class A biothreat agent because it easily passes from person to person through respiratory droplets and has a dangerously high mortality rate.

In just three historic pandemic outbreaks, it is estimated that Y. pestis has killed 200 million people, though only approximately 2,000 new cases are reported each year to the World Health Organization. Several multi-drug resistant strains have been identified in recent years.