The plague is back? It never really left

The plague, a rare bacterial infection infamous for causing the deaths of millions in 14th-century Europe, has never truly disappeared. It remains treatable with antibiotics since the 1990s. Most human cases have been reported in Africa, particularly in the Congo and Madagascar, according to the World Health Organization. In the U.S., an average of seven cases per year are recorded, mainly in rural areas of the American West.

Recently, a worker at a plague research institute in Siberia died of pneumonia, causing concern in Russia after unverified reports claimed she might have succumbed to pneumonic plague. Russian authorities, however, stated that testing did not detect plague. Consequently, the research institute has been placed under quarantine. The perception that the plague has vanished is incorrect; it still exists among us, warned Simon Clarke of the University of Reading in the U.K. Eradicating the bacteria is improbable due to the presence of wild animals, which are a constant source of the disease.

Throughout history, people in Siberia have been succumbing to plague for at least 5,500 years, as evidenced by teeth fossils from ancient hunter-gatherers north of Lake Baikal. The two primary forms of the plague are pneumonic and bubonic, both caused by the same bacterium, Yersinia pestis. The pneumonic form, which infects the lungs, and the septicemic form, an infection in the bloodstream, are both fatal if not treated promptly.

The bubonic plague, the most common form, manifests as swollen lymph nodes, fever, chills, headaches, and abdominal, leg, and arm pain. If left untreated, it can develop into the other two forms. People can contract the plague through bites from infected fleas, contact with infected bodily fluids, or inhalation of respiratory droplets from an infected individual with pneumonic plague. While the latter can be transmitted through close contact, it is unlikely to spread widely.

Although there is no plague vaccine available in the U.S., antibiotics are effective in treating the infection when detected early. Vaccines are recommended only for high-risk individuals, such as laboratory and healthcare workers, due to limited evidence of their efficacy against the pneumonic form.