Although plague is often thought of as a disease of the past, it remains a current threat in many parts of the world, and the number of countries reporting plague has increased in recent decades, says a team of researchers in this week’s PLoS Medicine.
Following the re-appearance of plague in the 1990s, particularly in Africa, the disease has been classified as re-emerging, say Nils Stenseth (Dept of Biology, University of Oslo, Norway) and colleagues. The plague bacillus, Yersinia pestis, causes several thousand human cases per year.
Over recent years, there has been a major shift in cases from Asia to Africa, with more than 90% of all cases and deaths in the last five years occurring in Madagascar, Tanzania, Mozambique, Malawi, Uganda, and the Democratic Republic of the Congo (DRC). Most are cases of bubonic plague contracted through contact with infected rodents and fleas, although outbreaks of pneumonic plague (directly transmitted from human to human via inhalation of infected respiratory droplets) still occur. The most recent large pneumonic plague outbreak was 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,” say the authors, “but it far exceeds them in pathogenicity and rapid spread under the right conditions.”
“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.”
Citation: Stenseth NC, Atshabar BB, Begon M, Belmain SR, Bertherat E, et al. (2008) Plague: Past, present, and future. PLoS Med 5(1): e3.
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