We are now in the midst of pandemic of a coronavirus disease called COVID-19 caused by a virus called “severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2), and there is some anxiety regarding certain unknown aspects of this virus. For example, the death rates appear significantly higher than those of the regular flu (note however that COVID-19 is not a flu or even related to the flu), but there is uncertainty as to whether this is due to an underreporting of milder non-lethal cases. However, the majority of deaths seem to occur among older weak people with previous health problems, and infected people that do not yet have symptoms upon viral infection do not seem to be a major driver behind the spread of the virus. Will COVID-19 turn out to be a disease no more serious than the flu, or will it be much worse?
In a previous post I quoted the late horror writer, H. P. Lovecraft, who wrote that “The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown.” But even as we remain somewhat fearful about what we don’t know regarding COVID-19, we must remember not only what we do know about diseases today and the fact that we have the tools fight them, but also how little we knew about them in the past and how helpless we were.
Let’s start with the Black Death.
The Bubonic Plague or Black Death ravaged many areas of the world in antiquity. The disease is caused by a bacillus, Yersinia pestis, which infects rats (although other animal hosts are also common) and is then transmitted to humans by fleas that bite infected rats. The most famous outbreak of the plague was that which occurred in Europe from 1347 to 1351 and which wiped out an estimated two thirds of the continent’s population (about 50 million people). Poor public hygiene and crowded living conditions in Europe created an excellent environment for the spread of disease. The role of germs or insects in the causation of disease was unknown, and physicians were helpless against the onslaught of the disease which was blamed on several things ranging from foul air and unfavorable planetary alignments to divine punishment for sins.
Today it is difficult to comprehend the sheer level of terror triggered by the plague in Europe and the breakdown of society and institutions that it caused. Corpses accumulated in the streets. Family members abandoned their dead and dying. Government officials, doctors, and priests deserted their posts. In some cities up to 80% of the population was wiped out. Some rulers instituted draconian measures like boarding up houses with all the occupants inside if one person in the house was infected, thus condemning all those inside to die. Ignorance, superstition, and fear combined to trigger barbaric behavior in mobs of people that targeted and killed individuals or certain groups of people like gypsies or Jews who were rumored to be behind the causation of the plague.
Several plague pandemics ravaged Europe over hundreds of years causing the death of millions. It was only in 1894 that the Swiss-French physician, Alexandre Yersin, discovered the plague bacillus and the role of rodents in its spread, and in 1898 the French physician Paul-Louis Simond discovered the role of fleas in the transmission process. This allowed the implementation of effective public hygiene measures that finally controlled the disease.
Now let’s move on to the so called Spanish Flu.
From 1918 to 1919 an influenza pandemic called the Spanish Flu killed 50 million people in the world and 500,000 in the United States. Due to World War I, any news about the flu that could be used as propaganda by the enemy was censored in many countries including the US, but the general public could tell that something out of the ordinary was going on. Unlike previous flu infections, this strain of influenza mostly affected and killed people in the prime of their life (20 - 40 years old), and it quickly overwhelmed the health care system in many localities which had to resort to interring the dead in mass graves. There was no way to treat influenza or the deadly secondary infections it generated, so fighting the disease consisted on mostly preventive measures such as good hygiene, quarantine, closing venues where large numbers of people congregated, and supportive care for those infected. The fear of the times of the plague returned. Scores of people locked themselves in their houses, refused to help their neighbors, and refused to go to work emptying the streets of some cities and towns.
The causative agent of the flu was originally believed to be a very small bacterium, but the development of the field of virology eventually led to the understanding that the flu is caused by viruses. With the invention of the electron microscope in the 1930s, viruses like the ones that cause the flu could be visualized. In 1999 the Spanish Flu virus was recovered from people who died during the pandemic. The virus was reconstructed in 2005 and studied to figure out what made it so virulent.
So how do the last two pandemics compare to the COVID-19 pandemic today?
Unlike what happened with the Black Death or the Spanish Flu, we know exactly what COVID-19 is. We know what the virus looks like, and what it does and how it does it. We have a good idea of where it originated and how. We have sequenced its genome in record time, and used that information to make test kits that permit the identification of those people that are infected, so they can be quarantined and questioned about their contacts and the places they have been. We have antibiotics to treat secondary infections triggered by the virus. We are testing antivirals that may be of use against the virus, and we have also begun to develop vaccines. There is a vast worldwide network of organizations such as the Global Virus Network and the World Health Organization that are tracking the spread of COVID-19 and coordinating the sharing of information among experts in different disciplines at every level and informing the public. There are government agencies such as the Centers for Disease Control and Prevention (CDC) in the U.S. that are monitoring the individual cases in a given country, coordinating the public health response, and advising the government and the general population.
Humanity’s knowledge of disease and its response to it has come a long way since the times of the Black Death and the Spanish Flu. We will continue fearing the unknown, but thanks to science this “unknown” has been made much smaller. Today we fear less.
The painting of Marseille during the Great Plague by Michel Serre is in the public domain. The photograph of an emergency hospital during influenza epidemic in Camp Funston, Kansas, circa 1918 is from the National Museum of Health and Medicine, and is used here under an Attribution 2.0 Generic (CC BY 2.0) license. The transmission electron micrograph of a SARS-CoV-2 virus particle (that produces the disease COVID-19), isolated from a patient, was captured and color-enhanced at the National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility (IRF) in Fort Detrick, Maryland, and is used here under an Attribution 2.0 Generic (CC BY 2.0) license.