By EDUARDO GONZALES
Q—With reports from China of several cases of plague, is there a danger of the disease spreading across the globe and causing another pandemic? What causes plague and how is it transmitted?—firstname.lastname@example.org
A—In the last several months there have indeed been two reports of plague cases in China. In May, a Mongolian couple reportedly died from bubonic plague after eating the raw kidneys of a marmot and last month (November), two people, also from Mongolia, were reported to be undergoing treatment in Beijing for pneumonic plague.
Bubonic and pneumonic plagues are the two main clinical forms of plague infection or “Black Death,” one of the deadliest diseases in human history. The third form of the disease is septicemic plague. Plague is caused by the bacteria, Yersinia pestis. When untreated it is highly fatal.
The death rate from untreated bubonic plague is a high 85 percent while that from untreated pneumonic plague is almost 100 percent. Three great pandemics of plague occurred in Europe in the Middle Ages. The one that occurred in the 14th century killed more than 100 million people in 50 years and reduced the population of Europe by at least a quarter.
Although the cases in China have received a lot of media coverage, they are actually not isolated cases. Plague has never been eradicated. It is currently still prevalent worldwide. According to the WHO, from 2010 to 2015, more than 3,248 cases of the disease were reported worldwide with the Democratic Republic of the Congo, Madagascar, and Peru as the most endemic countries. Even the United States is affected by plague—there have been anywhere from a few to a few dozen cases of plague with a few deaths every year, according to the US Centers for Disease Control and Prevention.
Plague is now categorized by the WHO as a re-emerging disease after close to 50,000 human cases have been reported during the past 20 years, but this categorization should not be a cause to worry. A pandemic of the disease is never really going to happen again because conditions in the middle ages are very different from what they are today.
Back then, people didn’t even know bacteria exist. Today, we already have antibiotics that are very effective in killing the bacteria Yersinia pestis. The current death rate from plague is a low one to five percent. With the antibiotics and modern public health interventions, any outbreak of plague will surely be easily contained.
Transmission and manifestations of plague
Plague is primarily a disease of rodents (e.g., rats) among whom the bacteria is transmitted by bites of fleas or ingestion of the feces of the fleas that infest them. The disease can be transmitted to humans in the same manners, i.e., by the bite of plague-infected fleas or ingestion of the feces of the fleas.
But in addition, pneumonic plague can be transmitted from human to human by inhaling droplets that have been exhaled or coughed out by the person with the disease. Plague is characterized by sudden onset of high fever, weakness and muscular pains two to six days after infection.
In the bubonic form, there is also swelling of lymph nodes (“kulane” in Filipino); in the septicemic form where the bacteria invades the blood stream, many organs and tissues get damaged giving rise to a variety of symptoms; while in the pneumonic form, which affects the lungs, there is shortness of breath, cough, and chest pain.
Plague is curable and preventable?
Plague is still endemic because low levels of the plague bacteria persist among populations of certain rodents. These infected animals and their fleas serve as long-term reservoirs for the bacteria.
Plague is curable with modern antibiotics, especially if given early in the disease. There is currently no vaccine against plague. The key to prevention of the disease is the control of the rodent population in the community.
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