A few weeks back, online news outlets were flooded with news of a bubonic plague case in Bayannur, Inner Mongolia. A local herdsman contracted the disease under unspecified conditions and is now quarantined and in stable condition. What the deeply alarmist tone of these articles failed to convey was that this incident, albeit unfortunate, was completely in line with the plague’s current epidemiological patterns. The demand for COVID-19 coverage has allowed many reporters to get away with highly inflammatory news pieces about both the current pandemic and the local emergence of other diseases, regardless of whether the latter has any significant epidemiological implications. Most of these articles focus on China, which has been bearing the brunt of coronavirus journalism, with little concern among Western reporters about whether that indicates an issue of anti-Asian sentiment.

Although the consequences of irresponsible journalism merit a thinkpiece of their own, they present us with the opportunity to gain a deeper understanding of how the plague works. Let’s take a gander at what the plague is – and what it’s not.

Modern-day plague and the Black Death

What we refer to as the plague is a disease caused by the Yersinia pestis microbe, a bacterium that is speculated to have infected human communities as early as the Bronze Age. While typical plague imagery has popularized rats as the source of infection for humans, that is not the case: it’s rat and human fleas that are responsible for transmitting the disease, with several species of rodents serving as plague reservoirs across natural ecosystems, most notably steppes.

Y. pestis can spread as three different types of plague: pneumonic, which attacks the lungs, septicemic, which infects the blood, and bubonic – possibly the most infamous of the three – which appears in the form of swollen lymph nodes. Human history is tainted with a series of plague pandemics that ebbed and flowed all the way until the 19^th century steamship plague, which started in China and claimed close to 10 million lives. Earlier Y. pestis outbreaks include the Plague of Justinian, which had a death toll of 100 million between 541-549 AD, and the Second Outbreak, which started in 14^th century Europe and decimated 30-60% of the continent’s population.

Today, Y. pestis has been contained to a much more manageable pattern: according to the World Health Organization, the average number of yearly plague cases is in the low thousands. The mortality rate has plummeted accordingly, with the Center for Disease Control estimating it at 11% if the patient receives treatment as opposed to 50-60% if they remain untreated. Additionally, transmission now happens almost exclusively through the handling of vector animals, and WHO reports that the vast majority of cases emerge around the carriers’ natural ecosystems. As of the 90s, there has been a steep increase in instances of Y. pestis in Africa, although it emerges routinely in all continents except Oceania.  

Easing concerns

As we slowly adapt to life during the coronavirus pandemic, many grapple with the fear of older, much more formidable diseases reemerging. It is beyond question that COVID-19 pales in comparison with such pandemics as the plague, polio, and HIV; and yet, a series of adverse sociopolitical circumstances has compromised many countries’ response to the current outbreak. How would we fare against a disease with higher transmissibility or more severe symptoms?

To give an educated answer to this question, we must first understand that epidemics don’t exist in a void. Different kinds of disease interact with and antagonize one another; and more often than not, our response to one outbreak can skew the chances of success for another. In a grim example of the above, the spread of tuberculosis effectively spelled the end of a large-scale leprosy epidemic in medieval Europe. Some scientists theorize that the similarities between the two pathogens helped cross-immunize tuberculosis patients against leprosy, while others posit that the opportunistic killing pattern of TB eradicated the weakened leprosy patients first, preventing them from spreading the disease.

In the same spirit, the precautions we take against COVID-19 are effective against an armada of other diseases. The principle of self-isolation would likely impede the spread of heavy hitters like the pneumonic plague – should a pandemic actually break out – simply by virtue of the Black Death being transmissible through the exchange of droplets; much like the coronavirus. More realistically, COVID-19 could serve as a trial period for adhering to safety protocols and for governments to assess the effectiveness of their healthcare and welfare policies. The history of epidemiology is riddled with tales of human communities taking the trial-and-error approach to mitigating deadly pandemics. In a sense, the relatively low stakes of this outbreak provide us with the opportunity to detect flaws that would prove fatal against high-mortality diseases.

In order to successfully respond to future pandemics, however, it is also important to recognize that many of these flaws stem from bias and propaganda rather than the healthcare system itself. In the 14^th century, the plague panic and festering anti-Semitism in European societies led to extensive attacks against the Jewish community. Prejudiced Christians placed the onus of spreading the disease on Jewish people, going as far as suggesting that they were deliberately poisoning drinking wells with the plague. Jewish communities across the continent were subjected to torture and massacres, which local governments either allowed or abetted.

In 2020, the emergence of COVID-19 in China fanned the flames of anti-Asian racism across the globe; and while the recentralization of the pandemic in the United States relieved China from the spotlight, offensive language still persists in common talk and poor journalism. Combating a global pandemic is as much a matter of great healthcare as it is a matter of international solidarity. Unless the conditions that allow discrimination are eliminated, it is likely that scapegoating, propaganda, and bias will persist in future outbreaks.

The plague and climate change

Although the reigning theory suggests that the plague spread across cultures by means of travel and trade, scientists are now considering a link between the disease and climate change. Nowadays, climate change is mostly being driven by human activity; but the climate has also shifted naturally throughout the history of the Earth. For instance, researchers at the University of Oslo found that between 1250 and 1850, unfavorable climate fluctuations in Pakistan’s Karakorum Mountains drove rodents away from their original habitats and closer to human communities. A few years later, instances of the plague appeared in nearby ports. This isn’t surprising, seeing as present-day climate change has been displacing animal and human populations for some time now. However, this precedent paints a worrisome picture on how plague reserves could move across ecosystems – and across the world – depending on the direction in which the climate is changing.

The threat of pandemics increasing in frequency as climate change occurs exists beyond speculation. The scientific community has identified multiple threats to public healthcare that are tied to environmental factors, like antibiotic-resistant superbugs frozen in the melting ice caps of the High Arctic. While climate change mitigation is crucial to preventing the emergence of our epidemiological enemies – old and new – history proves that many outbreaks are inevitable. Understanding how disease has shaped human societies, economies, and policies over our long coexistence is the key to implementing effective pandemic responses. As we brace for a second wave of COVID-19, it’s important to consider the degree to which this experience has pushed us to fortify healthcare and disallow bias, allowing us to face the next pandemic as a cohesive social whole.

 Citations:

1. "WHO Report on Global Surveillance of Epidemic-prone Infectious Diseases", World Health Organization, Jan 2000,  available at: https://www.who.int/csr/resources/publications/surveillance/plague.pdf

 2. "Maps and Statistics: Plague in the United States", Center for Disease Control, Nov 2019, available at: https://www.cdc.gov/plague/maps/index.html

3. Sarah Zielinski, "Plague Pandemic may have been driven by climate, Smithsonian Magazine, not rats", Feb 2015,  available at: https://www.smithsonianmag.com/science-nature/plague-pandemic-may-have-been-driven-climate-not-rats-180954378/

4. J. N. Hays, "The Burdens of Disease: Epidemics and Human Response in Western History", Rutgers University Press, 2009

5. Irwin W. Sherman, "Twelve Diseases That Changed Our World", ASM Press, 2007