Washington, January 15: A new study has revealed that plague, which is often considered to be a disease of the past, is still a threat in many parts of the world.
Published in PLoS Medicine, the study also reveals that the number of countries reporting plague has increased in recent decades. Nils Stenseth, a researcher at the Department of Biology at the University of Oslo, Norway, says that following the re-appearance of plague in the 1990s, particularly in Africa, the disease has been classified as re-emerging. The plague bacillus, Yersinia pestis, causes several thousand human cases per year.
A major shift in cases from Asia to Africa has been observed over recent years. Madagascar, Tanzania, Mozambique, Malawi, Uganda, and the Democratic Republic of the Congo (DRC) are the regions where 90 per cent of all cases and deaths took place in the last five years.
Most of such cases are of bubonic plague that spreads through contract with infected rodents and fleas, though outbreaks of pneumonic plague that is directly transmitted from human to human still occur.
The most recent large pneumonic plague outbreak took place in October and November 2006 in DRC, with hundreds of suspected cases, and a smaller outbreak arose just across the border in nearby Uganda in February 2007.
“Plague may not match the so-called 'big three" diseases (malaria, HIV/AIDS, tuberculosis) in numbers of current cases, but it far exceeds them in pathogenicity and rapid spread under the right conditions," say the authors.
“It is easy to forget plague in the 21st century, seeing it as a historical curiosity. But in our opinion, plague should not be relegated to the sidelines. It remains a poorly understood threat that we cannot afford to ignore," they add.