Plague: Past, Present, and Future
The Past:
Plague has given rise to at least three major pandemics. The first (the Justinian plague) spread around the Mediterranean Sea in the 6th century AD, the second (the Black Death) started in Europe in the 14th century and recurred intermittently for more than 300 years, and the third started in China during the middle of the 19th century and spread throughout the world. Purportedly, each pandemic was caused by a different biovar of Yersinia pestis, respectively, Antiqua (still found in Africa and Central Asia), Medievalis (currently limited to Central Asia), and Orientalis (almost worldwide in its distribution).
The Present:
Given this history, plague is often classified as a problem of the past. However, it remains a current threat in many parts of the world, particularly in Africa, where both the number of cases and the number of countries reporting plague have increased during recent decades. Following the reappearance of plague during the 1990s in several countries, plague has been categorised as a re-emerging disease.
The Future:
Plague cannot be eradicated, since it is widespread in wildlife rodent reservoirs. Hence, there is a critical need to understand how human risks are affected by the dynamics of these wildlife reservoirs. For example, the likelihood of a plague outbreak in North American and Central Asian rodents, and the resulting risk to humans, is known to be affected by climate. Recent analysis of data from Kazakhstan shows that warmer springs and wetter summers increase the prevalence of plague in its main host, the great gerbil. Such environmental conditions also seem to have prevailed during the emergence of the Second and Third Pandemics – conditions that might become more common in the future.
Plague may not match the so-called “big three” diseases (malaria, HIV/AIDS, tuberculosis; see for example) in numbers of current cases, 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.
Plague: Past, Present, and Future. 2008 PLoS Med 5(1): e3
Related:
- Ancient Plague
- Plague: From the 14th to the 21st century and still going strong
- A bacteriophage contributes to the pathogenicity of the plague bacillus
- How plague bacterium Yersinia pestis damages eukaryotic cells
Tags: Bacteria, Biology, Bioterrorism, climate, Emerging disease, Environment, Health, Medicine, Microbiology, Science
