Autoimmune Diseases Linked to the Black Plague

The Black Death was an unimaginable pandemic that swept through Europe in the mid-1300s, resulting in catastrophic and severe mortality of the global population at the time. The seven-year plague was responsible for up to 200 million deaths, a significantly more significant impact than the current coronavirus pandemic responsible for around less than 6.6 million deaths. Researchers studying gene mutations and modern human DNA recently discovered links between historic Black Death survivors and autoimmune diseases currently affecting millions of people.  

The significance of the Black Death’s impact at the time also coincides with a much smaller global population of around 392 million people, explaining why the plague had such an enormous impact and required centuries for the world to recover from the devastation. The plague was responsible for removing 30 to 60 percent of the European population at the time, meaning many modern humans of European descent originated from the remaining survivors. 

The enormity of the plague’s impact shaped humanity’s evolution, forcing the selection of survivable traits, which the researchers could observe in skeletal remains and descendants of the survivors. DNA analyses from the skeletons of plague survivors discovered genetic mutations that may have been the reason for greater individual survivability. The DNA study published in Nature found a series of mutations around the ERAP2 gene, equating to a 40 percent greater chance of surviving the plague for sampled individuals. 

The ERAP2 gene is responsible for generating proteins that divide and disperse invading microbes to immune system defenses, allowing it to recognize and neutralize invaders effectively. Survivors of the plague had mutations creating a high-functioning version of the gene, allowing their immune systems to overcome any infections by the deadly disease better. These plague-resistant mutations are still prevalent in today’s modern society as they were passed down through generations. However, modern-day humans may be inadvertently affected by those same high-functioning qualities of the mutations.

The massive impact the Black Death had on earlier human populations has continued to affect modern-day society, implicating descendants of survivors with damaging health consequences. Scientists discovered the increased protein production from the high-functioning gene can be linked to various autoimmune disorders like the damaging inflammatory bowel disease called Chrons. Increased protein production by the specific genes consequently has a negative implication forcing the body to damage itself in response to minor microbial invasions or even the lack thereof. The correlation of the plague’s evolutionary impact to modern autoimmune diseases is baffling but will potentially lead to discoveries regarding these diseases’ origins and treatment. 

Human DNA studies are incredibly complex as they attempt to understand many factors like mutations, environmental pressure, survivability, and inheritance. Similar consequences caused by the Black Death are improbable in the wake of the ongoing coronavirus pandemic. Future descendants of covid survivors will not likely need to address mutation complications because of the low significant impact on global populations and the disease’s inability to impact humans over a diverse age spectrum. Coronavirus-19 statistically has the most significant impact on older people, with deaths over 65 accounting for more than 75 percent globally.