Throughout history, epidemics have had an historical impact equal to that of wars, revolutions and economic crises.  In The Historical Importance of Epidemics, Professor Frank Snowden explains the significant impact of pandemics throughout history and warns that epidemic diseases still pose a major threat to human well-being. According to Snowden, infectious diseases are too important to leave solely to doctors.  They are part of the big picture of historical change and have had an impact on religion, the arts, colonial expansion, the establishment of New World slavery, the rise of modern medicine and on strategies of public health.

Disease can be thought of existing in levels within communities.  These levels help understand the potential threat of disease and dictate the public health response.  The Centers for Disease Control and Prevention’s (CDC) Epidemic Disease Occurrence explains that disease can be sporadic, endemic, or hyperendemic and can rise to the level of an epidemic or pandemic.

Many infectious diseases are zoonotic, caused by microorganisms that spread between animals and people.  Zoonotic diseases can spread from animals to humans through direct contact, indirect contact, via vectors, or through food and/or water systems.  Pandemics happen when new (novel) disease causing agents emerge which are able to infect people easily and spread from person to person in an efficient and sustained way (https://www.cdc.gov/flu/pandemic-resources/basics/index.html).

Though science has come a long way in understanding infectious diseases, diseases of the past as well as novel emerging diseases, are a constant threat to public health (https://www.coursera.org/learn/epidemics).  Complex issues related to social networks, food safety and security, and environmental ecosystem destruction necessitate a holistic, not siloed approach to understanding and addressing epidemic diseases.

(Bats, Ducks, and Pandemics: An Introduction to One Health Policy). According to Snowden, how we deal with infectious diseases may be an important factor in whether and how we survive as a species (The Historical Importance of Epidemics)

Infectious diseases are experienced differently from chronic disease and give rise to distinctive fears and anxiety.  Chronic diseases can have massive impact, but do not give rise to scapegoating, mass hysteria, outbursts of religiosity, or works of literature and art.  Epidemic diseases are distinctive and leave a particular legacy in their wake.  Throughout human history, infectious diseases have been the most important cause of suffering and death (The Historical Importance of Epidemics).

Infectious diseases are one of the major causes of death, responsible for a quarter to one-third of mortality worldwide.  People living in low-income countries are far more likely to die of a communicable (infectious) disease than a noncommunicable (chronic) disease.  Despite a global decline from the years 2000 to 2019, six of the top 10 causes of death in low-income countries were communicable diseases.

A Historical Guide to Pandemic Responses is a series of short essays written by medical historians on previous epidemics and our responses to them.  The essays act as “signposts” to highlight historical research on prior responses to rapidly spreading disease among populations (https://www.hopkinsmedicine.org/news/articles/a-historical-guide-to-pandemic-responses).

Pandemics not only have social and public health effects, but also impact the economy as well.

In Pandemics and Financial Assets, Dr. Nzar Mohammad Alsharari discusses the ill effects of pandemics on the economy and presents how the financial markets and financial institutions were influenced by and responded to pandemics.

The CDC outlines the public health response to pandemics in their e-learning course Introduction to Public Health.

The bubonic plague is a highly infectious disease caused by the bacteria, Yersinia Pestis.  Archaeological evidence suggests its existence as far back as 542 C.E.  Symptoms include fever, headaches, vomiting, swollen and painful lymph nodes (buboes) and acral necrosis (dark discoloration of the skin) (https://www.cdc.gov/plague/symptoms/index.html).   There are three common clinical forms of the plague: 1) Bubonic; 2) Pneumonic; and 3) Septicemic.  Plague symptoms and clinical manifestations depend on how the patient was exposed to the plague bacteria.  Most victims of the plague died within four to seven days after infection.

The Black Death was the devastating epidemic of the bubonic plague which struck Asia and Europe in the mid-1300s.  The great pandemic of the 14th century is also known as the “Great Pestilence,” the “Great Plague,” and the “Great Mortality.”  It  began in 1331 in Southwestern China and spread through Asia to the Mediterranean via trade routes.  In October 1347, a Genoese ship docked in Messina, Sicily, bringing with it rats infected with the bubonic plague (Brief History of Pandemics-Pandemics Throughout History).

As a result, both of its extreme virulence and the strictness of the measures imposed to combat it, the plague significantly disrupted traditional customs of dealing with death. This disruption made itself felt not only in religious belief and burial practices but also in art, architecture, and literature. European culture was profoundly shaped by the experience of the plague, as witnessed by the advent of symbols such as “vanitas” and the danse macabre in iconography, as well as the visual representations associated with the new cults of plague saints. The successful containment of the plague might be seen to have exercised a similarly powerful effect in shaping the philosophical project of the Enlightenment, in that the measures taken to ward off death gave material substance to theoretical claims of progress. (Open Yale Course: HIST 234: Epidemics in Western Society Since 1600, Lecture 5).  The period of the Black Death was the first time society implemented organized anti-plague measures (i.e., quarantine, isolation, and systems of sanitation control that included observation stations, isolation hospitals, and disinfection procedures)

In Pandemic Disease in the Medieval World: Rethinking the Black Death, writers compare the Black Death and Ebola epidemics.  Each essay focuses on a different aspect of comparison. For example, one essay analyzed the impact of the Black Death on the Jewish community in Tarrega as an example of how the pandemic lead to escalating attacks on social minorities The essays highlight the need to understand local outbreaks and how mathematical modeling can be used to detect early, “silent” phases of transmission.

Smallpox is a serious infectious disease caused by the variola virus. While the origin of smallpox is unknown, the growth of civilizations and exploration is blamed for the global spread of the virus. People who had smallpox had a fever and a distinctive, progressive skin rash. Once the first sores appeared in the mouth and throat, they were contagious and remained contagious until their last smallpox scab fell off. The virus was spread when they coughed or sneezed and droplets from their nose or mouth spread to other people. Most people with smallpox recovered, but about 3 out of every 10 people with the disease died. Many smallpox survivors have permanent scars over large areas of their body, especially their faces. Some were left blind. Smallpox was eradicated as a result of vaccination: the last natural outbreak of smallpox in the United States occurred in 1949. https://www.cdc.gov/smallpox/about/index.html

In the eighteenth century, smallpox succeeded plague as the most feared disease.

Smallpox is viral and transmitted by contact and airborne inhalation. Unlike plague, smallpox can exist as an endemic as well as an epidemic disease, https://oyc.yale.edu/history/hist-234/lecture-6

The COVID-19 pandemic marks the 300th anniversary of the Boston smallpox epidemic of 1721. The epidemic ultimately resulted in an early effort at preventive medicine through vaccination, resulting in a successful public health campaign to eradicate the disease. https://cuny-bc.primo.exlibrisgroup.com/permalink/01CUNY_BC/ljnr3v/cdi_proquest_miscellaneous_2622961987

Cholera is an acute diarrheal illness caused by infection of the intestine with Vibrio cholerae bacteria. People typically get sick when they swallow food or water contaminated with cholera bacteria. The resulting infection is often mild but can sometimes be severe and life-threatening. Large epidemics are often related to fecal contamination of water supplies or street vended foods. https://www.cdc.gov/cholera/general/index.html

Asiatic cholera was the most dreaded disease of the nineteenth century. An intense fear provoked by the disease was its symptoms: not only did cholera exact a degrading and painful toll on the human body, it also struck suddenly, and was capable of reducing the seemingly healthy in a period of hours. A second major reason for the disease’s significance was its overwhelming predilection for the poor, https://oyc.yale.edu/history/hist-234/lecture-10

Seven pandemics of cholera have been recorded since the first pandemic in 1817. Overcrowding, poverty, insufficient water, and sanitation facilities increase the risk for cholera outbreaks, https://pubmed.ncbi.nlm.nih.gov/31395455/. Cholera persists as a major cause of illness and death worldwide, with more recent epidemics in Zimbabwe (2008-2009) and Haiti (2010), https://pubmed.ncbi.nlm.nih.gov/22099113/

The diagnosis of the flu is not a new one and while a single case of the flu does not cause alarm, the potential for widespread exposure and illness does. Professor Robert Dingwall, of Nottingham Trent University, provides an historic overview of the seasonal flu, avian flu and a flu pandemic (https://www.oercommons.org/courses/flu-pandemic-how-prepared-are-we-3)

Records of influenza, dating back to the 1700s, suggest a pattern of one major pandemic every century. Among the pandemics for which there is documentary evidence, the outbreak of 1918-1920 is by far the greatest, https://oyc.yale.edu/history/hist-234/lecture-20

Dr. Michael Gregor provides an interesting overview of the birth of influenza, that was presumed not to exist before the domestication of  animals. While this is an older source, the information remains relevant when discussing the history of influenza. https://youtu.be/7_ppXSABYLY

The Influenza Encyclopedia is a storehouse for stories about the places, people, and organizations that battled the American influenza epidemic of 1918-1919. Included are stories from all 50 U.S. states and documents how communities across the country did what they could to stem the rising tide of illness and death as well as how many gave their time and their lives to care for the ill. (Influenza Encyclopedia).

In an historical retrospective review of the impact of the 1918-1919 influenza pandemic,  a panel of experts discusses how the pandemic affected daily life in the United States and what lessons can be learned and applied to planning today.  Pandemic Influenza-Past, Present, Future: Communicating Today Based on Lesson from the 1918-1919 Influenza Pandemic U.S. Department of Health and Human Services Centers for Disease Control and Prevention October 17, 2006 The Oak Ridge Institute for Science and Education

The Open Yale Course: Poliomyelitis describes the history of poliomyelitis, better known as polio, focusing on the large public health campaign designed to eradicate it.  The campaign was modeled after the successful smallpox initiative, although due to differences in the diseases, was more limited in success.  Sanitary improvements in many nations across the globe helped to contribute to it being considered a “social disease in reverse” in that large populations in more industrialized nations had no natural immunity to the virus, resulting in outbreaks in these areas.  Diagnosis was also often delayed or not correctly made because physicians were not trained or expecting to identify it.  Additionally, incorrect assumptions were made about transmission, slowing development of a vaccine.  The video further describes the steps leading toward the successful development of vaccines, the involvement of Salk and Sabin,  the impact of the March of Dimes, the fact that the US President (FDR) had been paralyzed from polio, as well as the large-scale vaccination initiatives implemented within schools and elsewhere.

The World Health Organization (WHO) website provides an overview with symptoms and treatment, and highlights how two of the three types of polio have been eradicated, while poliovirus type 1 continues to be present in Pakistan and Afghanistan.

ASBMB Today (American Society for Biochemistry and Molecular Biology) highlights how the polio vaccine made its way from lab to public distribution with video, data and photos which describe the large public health campaign designed to eradicate the disease.

The CDC highlights that the history of tuberculosis (TB) can be traced back more than 9000 years in humans, via remains of a mother and child found in the Middle East region.  Written descriptions of TB can be found as early as 3300 years ago in India.  It is estimated that from the 1600s to the 1800s, approximately 25% of all deaths in Europe and the US were attributable to TB, a form of which during that period was frequently referred to as “consumption.”

The Open Yale Course Tuberculosis (I): The Era of Consumption traces the earlier history of the pulmonary disease consumption, discusses whether it should be classified as epidemic, endemic, or both, and follows its progression and upsurge in increasingly industrialized areas.  The video covers the earlier history of transmission and symptomatology through discovery of the mycobacterium tuberculosis in 1882 by Robert Koch, as well as the varied ways it can be transmitted, and the various organs and tissues of the body it can impact, as highlighted by images within the presentation.  The video additionally covers the social impact of the disease, with references to sweatshop factories, cramped living conditions in homes and within institutions such as prisons, and to well-known people, such as royalty and famous writers who contracted the disease.  It also describes how individuals who contracted the disease sometimes made “health migrations,” in search of an environmental climate more conducive to respiratory health.  It also describes how TB influenced romantic works such as those from Emily Bronte and Victor Hugo.

While consumption was sometimes romanticized during the period leading up to Koch’s discovery, the Open Yale Course: Tuberculosis (II): After Robert Koch highlights a shift in the way in which TB was addressed once it more consistently became known as an infectious danger. What is referred to as the “war on TB”  resulted in an increase in sanatoria, an international movement which became a growing way to address the disease via dietary changes, isolation, and increased outdoor time which served as a quarantine treatment for the disease. The video covers research and treatment through the earlier part of the 20th century until the ultimate introduction of antibiotics in the 1940s.  While not eradicated (despite projections that it would be eliminated in the US by 2010), antibiotics did result in significant decline in TB cases from the 1950s through 1985.  However, starting in the 1950’s drug-resistant TB strains began to increase.  Between 1970 and 1990 there were numerous outbreaks of drug-resistant tuberculosis.  A rise in drug-resistant TB increased numbers worldwide, with pandemic levels in Europe and sub-Saharan Africa.  As with other diseases, there has been an overrepresentation of the disease in minority and other underserved populations. The CDC differentiates Active vs Latent TB in this article.

Chris Beyrer described four decades of the emergence, impact, and response to the global HIV/AIDS pandemic in a Lancet article which compares and contrasts various aspects of COVID-19, including issues of equity, geography, and the focus of research scientists on development of treatments and vaccine.  The trials, tribulations and timeline of a COVID-19 vaccine compares development to that of an HIV vaccine.

The video Open Yale Course: AIDS covers the background, transmission, scale, epidemiology, societal effects, and public health strategies associated with HIV/AIDS through 2010.  The outbreak began in the early 1980s, peaked approximately ten years later before declining until 2001; however, it then experienced an upturn which continued into the 2010s. It is now common knowledge that HIV can be transmitted via the exchange of infected bodily fluids such as blood, breast milk, and semen.  As we have seen with other pandemics, early reports of the disease created uncertainty which delayed response to its spread.  In this case, since early reports were of infections among gay men, the stigma attached to the media coverage focused on this population while the spread was not limited to a singular population or geography.

While advancements have been introduced which have limited deaths,  living with HIV as a chronic disease presents challenges, including those associated with the expanded use of expensive drug cocktails.  The Yale Course additionally highlights how the disease continues to be rampant in sub-Saharan Africa, where half of the world’s HIV infections exist, and life expectancy at birth dropped to below 50 years of age (and, in some areas, to below 40 years of age) for the first time since the 1950s, largely due to HIV.  The AIDS pandemic has currently  globally stabilized but it has also transformed with concerning spread in certain parts of the world and with increased impacts to ethnic minority populations.

A Timeline of HIV and AIDS  covers the history of HIV/AIDS in the U.S. from the first reported cases in 1981 to present day.

In December, 2019, a cluster of patients in Wuhan, Hubei Providence, China were diagnosed with pneumonia of unknown etiology.  All the cases were connected to the Huanan Seafood Wholesale Market in Wuhan.  January 2020, Chinese authorities identified and isolated the novel coronavirus as the causative agent of the outbreak.  The first confirmed case in the U.S. was discovered in Washington state, later in January.  In March 2020, the World Health Organization declares COVID-19 a pandemic. (https://www.cdc.gov/museum/timeline/covid19.html).  Despite significant advances in science and medicine, the COVID-19 pandemic spread rapidly and caused major impacts around the world.

The highest percent of COVID-19 cases are among non-Hispanic White people. However, racial and ethnic minority groups are disproportionately represented among COVID-19 cases. The percent of cases for racial and ethnic minority groups are higher than the percent of these populations within the total U.S. population. Comparing the percent of cases and the percent of the total U.S. population by race and ethnicity provides an indication of disparities. This comparison is not exact because not all geographic areas report COVID-19 case data by race and ethnicity. Non-Hispanic White people represent a majority of the U.S. population (60%), followed by Hispanic or Latino people (18%), non-Hispanic Black people (12%), non-Hispanic Asian people (6%), non-Hispanic people who identify with more than one race (3%), American Indian or Alaska Native people (1%), and Native Hawaiian or other Pacific Islander people (less than 1%).   Among people aged less than 50 years, and notably among children aged less than 18 years, a noticeably higher percent of COVID-19 cases are among Hispanic or Latino people compared with the percent of the total U.S. population. Hispanic or Latino children represent 25% of the U.S. population aged less than 18 years (https://www.cdc.gov/coronavirus/2019-ncov/community/health-equity/racial-ethnic-disparities/increased-risk-illness.html).

Recent studies have consistently found that among those tested for COVID-19, non-Hispanic Black, Hispanic or Latino, and people who identify with more than one race and are non-Hispanic were more likely to have positive test results as compared with non-Hispanic White or non-Hispanic Asian people. Comparing percent of COVID-19 test results that were positive (percent positive) among racial and ethnic populations can be helpful for understanding the spread of COVID-19 in the community. It is important to continue to monitor access, testing, and results to understand trends in transmission and groups that may be disproportionately affected by COVID-19. It is important to understand why people are getting tested and to recognize if reasons change over time or are different for particular groups. For example, people who have easier access to testing may be more likely to get tested sooner after onset of symptoms or known exposure or more often. People who do not have easy access to testing may wait until they are sicker before getting tested (https://www.cdc.gov/coronavirus/2019-ncov/community/health-equity/racial-ethnic-disparities/increased-risk-illness.html).

The social distribution of COVID-19 exposure factors (density of place of residence, overcrowded housing and working outside the home) are described in detail by Bajos et. al (https://bmjopen.bmj.com/content/11/11/e052888).   Multinomial regressions were used to identify changes in social variables (gender, class and race) associated with symptoms of anosmia/ageusia (partial or full loss of smell/loss of taste). Women were more likely to report symptoms during the peak and after. Racialized minorities accumulated more exposure risk factors than the mainstream population and were at higher risk of anosmia/ageusia during the peak and after. By contrast, senior executive professionals were the least exposed to the virus with the lower rate of working outside the home during lockdown. They were more affected than lower social classes at the peak of the epidemic, but this effect disappeared after the peak.

As of April 2022, COVID-19 is the third leading cause of death after heart disease and cancer.  Like past pandemics, the COVID-19 outbreak has been particularly detrimental to members of those social groups in the most vulnerable situations, (i.e., people living in poverty, older persons, persons with disabilities, and indigenous peoples).  Early on, evidence indicated that the health and economic impacts of the virus were borne disproportionately by poor people.  Overall death rates are highest among non-Hispanic American Indian/Alaskan Native and non-Hispanic Black or African American people.

As demonstrated by the 2020 COVID-19 global crisis, communicable diseases – especially those caused by respiratory pathogens – can spread wider and faster across countries and continents than ever before, in large part due to increased global travel and trade. In the last decades, other diseases such as influenza, SARS, MERS, Ebola, Zika, plague and yellow fever have been examples of high-impact, fast-spreading diseases causing frequent outbreaks which are increasingly difficult to manage. Urbanization and population growth, climate change and other environmental issues may also augment the risk of threats having a potentially high cost for human health and a severe impact on economies and societies (https://drmkc.jrc.ec.europa.eu/initiatives-services/epidemic-intelligence-from-open-sources#documents/1033/list).

The Epidemic Intelligence from Open Sources (EIOS) initiative is a unique collaboration between various public health stakeholders around the globe. It brings together new and existing initiatives, networks, and systems to create a unified all-hazards, One Health approach to early detection, verification, assessment, and communication of public health threats using publicly available information (https://www.who.int/initiatives/eios).

This course demonstrates how to conduct epidemiologic surveillance to gather data to inform decision-making and planning.  It uses the polio eradication effort as a case study (https://www.futurelearn.com/courses/collecting-and-using-data-for-disease-control).