Infectious Diseases and Epidemics


Despite Philadelphia’s prominence, throughout its history, as a center for medical education and care, the region has experienced numerous epidemics of infectious disease. British America’s largest city in the eighteenth century, Philadelphia suffered dreadful outbreaks of smallpox and yellow fever, while the nineteenth century brought an exotic new disease—cholera—that killed hundreds. By the early twentieth century, though rates of death from infectious disease remained high by modern standards, scientific advances began to limit their power. Nevertheless, epidemics of influenza, polio, and HIV/AIDS killed thousands through the turn of the twenty-first century even as diabetes, cancer, and cardiovascular disease accounted for an increased share of deaths in the region.

A black and white illustration of Benjamin Rush seated at a desk with papers
Dr. Benjamin Rush rose to prominence during the yellow fever epidemic of 1793. He became one of the first American physicians to gain international renown. (Historical Society of Pennsylvania)

Eighteenth-century Philadelphia was a crossroads of the Atlantic world. Decades before Philadelphia’s founding, the Lenni Lenape suffered near extinction from diseases brought by Swedish and Dutch colonials who built posts along the Delaware River. Philadelphia enjoyed a lower mortality rate than major European cities because of its relative isolation and generally better standard of living, but infectious disease claimed lives daily, and epidemics occurred every year. The region faced threats from three major sources of infection: contamination of food and water with typhoid and other intestinal pathogens; airborne pathogens such as smallpox and measles; and insect vectors carrying diseases, especially malaria and yellow fever, though dengue also circulated in the city.

Smallpox was among the most feared of the infectious diseases. Outbreaks occurred in Philadelphia every year and Philadelphia was probably the only place in the thirteen colonies where smallpox was endemic. The city’s relatively large size enabled the virus to find a continual supply of susceptible individuals. Survivors often bore large, pitted scars and became blind. During the Revolution, smallpox exploded into a general North American epidemic. Philadelphia, occupied by the British, was host to thousands of American prisoners of war, hundreds of whom died of smallpox in indescribably miserable conditions.

While smallpox captured the imagination with its high death rate and gross manifestations on victims’ bodies, less obvious infections claimed even more lives. Eighteenth-century Philadelphians drank water contaminated with fecal matter, which resulted in endemic typhoid, dysentery, and other intestinal diseases. Infants and young children, who were especially susceptible to dehydration, died in large numbers. The young, in particular, also faced threats from scarlet fever, whooping cough, measles, and diphtheria, which was especially dreaded for its ghastly symptoms. In the most virulent cases, a leathery membrane covered large portions of the tonsils and pharynx and killed through slow asphyxiation.

Mosquito-Borne Illnesses

A colored political cartoon of an ill man in bed surrounded by a crowd of doctors and an African American woman
Yellow fever loomed in the consciousness of Philadelphians long after the 1793 epidemic. (Library Company of Philadelphia)

Mosquitos found the region, with its many wetlands, an attractive breeding ground. Though its cold winters discouraged most tropical species from breeding, malaria sickened residents every summer, though most cases were milder than in the southern colonies where the Anopheles mosquito thrived. Dengue, referred to as “break bone” fever because of the excruciating pains that shot through the limbs and backs of sufferers, was also present in the city; the first major epidemic occurred in 1780. The most acute mosquito-borne illness, however, was yellow fever, which ravaged the city sporadically throughout the eighteenth century. The worst epidemic occurred in 1793, brought by ships arriving from the West Indies with infected tropical mosquitoes. By the onset of the first frosts in October, which killed off the mosquitoes, 10 to 15 percent of the city—between four and five thousand people—had died. The epidemic prompted a mass exodus of the city by those who could afford to leave, while those left behind often relied on African American citizens to render assistance and bury the dead.

A black and white photograph of the Lazaretto as it appeared in the 1980s
The Lazaretto is the nation’s oldest surviving quarantine hospital. All passenger ships entering Philadelphia in the nineteenth century were required to dock here so that the passengers could be inspected for infectious diseases. (Library of Congress)

Philadelphia’s high mortality rate from infectious disease during the colonial era revealed a lack of effective treatments. Physicians and surgeons understood a great deal about human anatomy by the middle of the eighteenth century and were able to suture wounds, set fractures, remove decayed teeth, and attend births. But doctors never suspected the causative agents of infectious disease were microscopic organisms. Standard responses to sickness included bleeding; application of caustic plasters to the skin to provoke blistering, which physicians believed would draw out poisons; and induction of vomiting with ipecac or diarrhea with calomel to purge the body. Such interventions often did more to hasten death than speed recovery. To ease pain, quiet a persistent cough, or stem diarrhea, doctors might use opium or laudanum, a tincture of opium and alcohol. For syphilis, which was common in Philadelphia, doctors prescribed doses of mercury high enough to cause symptoms, consistent with heavy-metal poisoning, such as uncontrollable salivation and loosened teeth. Physicians also prescribed less onerous therapies such as dietary and rest regimes.

The most impressive weapon against disease was smallpox inoculation, famously championed by Benjamin Franklin (1706–90) after the death of his beloved son in 1736 from the disease. Philadelphia boasted several hospitals, most importantly the Pennsylvania Hospital, the Almshouse (later Philadelphia General Hospital), and the Lazaretto, as well as a growing cadre of physicians, most famously Benjamin Rush (1746–1813), who taught at the nation’s first medical school, at the College of Philadelphia (later the University of Pennsylvania), founded in 1765. Two dozen of the city’s leading physicians founded the College of the Physicians of Philadelphia, dedicated to the advancement of medical practice, in 1787.

A color political cartoon depicting cholera as a grim reaper figure on the bow of a ship flying British flags
Cholera, depicted here as a grim reaper, escaped its endemic Ganges River region and swept across Europe in the early nineteenth century. It reached Philadelphia in 1832. (Historical Society of Pennsylvania)

The population of Philadelphia exploded in the nineteenth century. As Philadelphia grew, it drained prodigious quantities of water from surrounding wetlands and diverted or obliterated numerous streams and ponds, decreasing mosquito breeding grounds. The press of people, however, further fouled water supplies. Cholera, a waterborne disease that originated in the Ganges Delta and caused a series of global pandemics, first entered the city in 1832 and killed hundreds. Repeated waves of cholera prompted greater attention to public health in Europe and America and ushered in new thinking about sewage and contagion. Typhus, a highly lethal disease spread by body lice, made its last appearance in Philadelphia in 1893, while smallpox, which state health authorities believed entered the city again with troops returning from the Spanish-American War, caused hundreds of deaths in Philadelphia during the first few years of the twentieth century before vaccination once again brought it under control. Of all infectious diseases, tuberculosis remained the “captain of death,” caused thousands of deaths in the region annually, and motivated the founding of hospitals, clinics, dispensaries, and research organizations.

Scientific Advances Ease Epidemics

Even as infectious disease killed thousands every year, scientific advances offered hope. The bacterial revolution between the 1850s and 1880s, which yielded growing evidence that microbes caused infectious disease, prompted Philadelphia to build the Philadelphia Municipal Hospital for Contagious Disease at Twenty-Second and Lehigh Streets in 1865 to isolate the sick and limit the spread of disease. By the mid-1890s, diphtheria antitoxin began to rescue victims, especially children, from the brink of death. The experiments of Benjamin Franklin Royer (1870-1961), head of the city’s contagious disease hospital, improved the effectiveness of the antitoxin regimen. Royer concluded that physicians should administer massive doses of antitoxin immediately when they suspected diphtheria, even before laboratory confirmation of the disease. Physicians across the country heeded Royer’s recommendations.

By World War I, Philadelphia filtered and chlorinated its water supply and watched as mortality from waterborne disease shrank to low background levels. Insect-vectored diseases, too, no longer posed a serious threat. Though most infectious diseases could not yet be cured, recognition of the importance of patient isolation, quarantine, cleanliness, and hygiene, along with increased access to hospitals and doctors all combined to reduce deaths from contagious disease.

a black and white photograph of five polio stricken children holding March of Dimes posters with Philadelphia March of Dimes leader
Poliomyelitis appeared in the early twentieth century. The paralytic infection’s casualties peaked in 1952, three years before a vaccine became widely available. (Special Collections Research Center, Temple University Libraries)

Still, in 1916, Philadelphia’s first major outbreak of polio sickened hundreds and paralyzed or weakened scores. Even more terrible than this specter of paralyzed and dying children was the influenza epidemic that raged across the world and emerged in Philadelphia in September 1918, the city’s first major epidemic since cholera, killing between thirteen thousand and nineteenth thousand people by March 1919. Philadelphia experienced the worst urban outbreak in the nation because the first appearance of the virus in the city coincided with a war bonds parade; the large crowds in attendance permitted the virus to infect thousands in one day, and tens of thousands within the next week. The large number of rapid deaths overwhelmed city services, with corpses languishing in apartments and mass burials the result.

Like the rest of the nation, however, Philadelphia entered the 1920s relatively free of infectious disease. Deaths from what are now vaccine-preventable diseases occurred at a much higher rate than they would a century later, but were a rarity compared to the rates experienced just a generation previous. The drop in mortality resulted mainly from public health measures that limited exposure to serious infectious disease, as well as from improved medical care. In the late 1930s, the first class of antibiotics—sulfa drugs—became available. A decade later, the introduction of penicillin, along with the rapid development of other antibiotics, led to the marked diminishment of bacterial infections, while the rapid introduction of vaccinations for diphtheria, mumps, whooping cough (pertussis), measles, polio, influenza, and tetanus further reduced sickness and mortality from infectious diseases. With the exception of polio and the influenza epidemics in 1957 and 1968, infectious disease ceased to be an important cause of death on the region’s component of mid-to-late-twentieth century mortality rolls.

Legionnaires’ Disease, 1976

A black and white photograph of a man at a Legionnaire's symposium pointing to a graph about the epidemic
Legionnaires’ disease baffled epidemiologists for almost six months after it appeared. The mysterious illness’s first victims were members of the American Legion who attended the organization’s 1976 convention at Philadelphia’s Bellevue-Stratford Hotel. (Special Collections Research Center, Temple University Libraries)

The hiatus from outbreaks ended, however, in 1976, when attendees of a convention of the American Legion in Philadelphia complained of weakness, fever, and shortness of breath. In little more than a week, more than two hundred convention-goers sickened and thirty-two died. The pathogen, a species of bacteria never linked to human illness, was named Legionnaires’ disease and forever linked to Philadelphia.

As the Legionnaires’ outbreak splashed across the headlines, another infectious killer stalked the city; by the mid- to late 1970s, the human immunodeficiency virus began its infiltration of Philadelphia, especially among the city’s intravenous drug users and gay men. By 1980, heterosexuals, too, especially hemophiliacs and those under age thirty, came into increasingly frequent contact with the virus. Deaths must have occurred, but because they were few and occurred in marginalized populations with limited access to medical care, they were missed. By September 1981, however, Philadelphia physicians diagnosed patients whose symptoms were consistent with those seen in the first reported cases in Los Angeles and New York a few months earlier. Throughout the 1980s and early 1990s, Philadelphia fought a rising tide of illness and deaths. Until the advent of retroviral treatment in 1996, Philadelphia relied on two classic principles of public health, isolation and prevention, to slow the virus’s destruction.

A black and white photograph of HIV/AIDS activists from ACT-UP Philadelphia marching with signs
AIDS activists believed that stigma surrounding the disease led politicians to avoid addressing it. Activist groups like ACT-UP Philadelphia, a local branch of a New York City-based organization, were formed to raise awareness. (John J. Wilcox LGBT Archives of Philadelphia)

With the exception of HIV, infectious disease—though it always posed a threat—failed to produce a major, high-mortality outbreak, let alone a citywide epidemic. One national study of mortality from infectious disease, applicable to Philadelphia, found that between 1900 and 1996, mortality from infectious disease decreased from 797 deaths per 100,000 of the population in 1900 to only 36 per 100,000 in 1980. The AIDS epidemic and increased deaths from influenza and pneumonia among the elderly increased the rate to 59 per 100,000 by 1996, but this was still less than 10 percent of the rate a century earlier. As deaths from infectious disease declined, cancer, cardiovascular disease, diabetes, and Alzheimer’s claimed a greater percentage of lives and became the major killers in the region.

Founded during the early modern era of medicine, Philadelphia and the surrounding region partook in and contributed to the sweeping changes in our understanding of disease during the nineteenth century—and remained on the cutting edge of research and treatment into the twenty-first century. Few major episodes in American medicine failed to touch the region and its people, while the work of the area’s physicians, nurses, engineers, and researchers improved the lives of people across the globe.

James Higgins is a lecturer in American history at the University of Houston–Victoria. He specializes in the history of medicine, especially as it pertains to Pennsylvania. His manuscript, which analyzes four urban outbreaks in Pennsylvania during the 1918–19 influenza pandemic, is with the University of Rochester Press. He has offered a dozen conference papers and several articles, invited lectures, and book chapters. (Author information current at time of publication).

Copyright 2016, Rutgers University


Dr. Benjamin Rush

Historical Society of Pennsylvania

One of Philadelphia's most renowned physicians, Benjamin Rush studied at the College of New Jersey (now Princeton University) before obtaining a medical degree at the University of Edinburgh, one of the most prominent medical schools in Europe. Upon returning to the city, he practiced medicine and served as a professor of chemistry at the University of Pennsylvania, and wrote the first text on the subject to be published in the colonies. He later became a professor of medicine at the university. From 1784 until his death, Rush was a surgeon at the Pennsylvania Hospital, the first hospital in the colonies. While there, he advocated for more humane treatment of the mentally ill patients, whom he often cared for.

In 1793, a particularly virulent epidemic of yellow fever gripped the city, which at that time was the seat of the federal government. Rush was one of the first doctors to correctly identify the illness. However, the typical treatments of the day, such as bloodletting and administering purgatives, likely worsened the conditions of patients. By the end of the epidemic, five thousand people--about 10 percent of the total population of the city–had died and nearly twenty thousand were evacuated. Rush's devotion to his patients and refusal to leave, even after he contracted the disease himself, made him a hero in the popular consciousness.

In the years after the yellow fever epidemic, Rush continued to practice medicine and wrote prodigiously, making him one of the first American physicians to gain international renown. Rush was also involved in politics beginning in 1776, when he attended the Second Continental Congress and became the only medical doctor to sign the Declaration of Independence. He was involved in the ratification of the U.S. Constitution in Pennsylvania in 1787, and was one of the politicians who pushed, successfully, for a new state constitution in 1789. A strong proponent of higher education, Rush founded Dickinson College in Carlisle, Pennsylvania, in 1783, and Franklin and Marshall College in Lancaster in 1787. That year he also helped found the College of Physicians of Philadelphia. He died in 1813.

A Case of Infectious Fever

Library Company of Philadelphia

Yellow fever is an acute viral infection spread by mosquitoes. It is named after the yellow appearance of the patient's skin. Other symptoms include fever, bloody vomit, and muscle aches. In 1793, a major epidemic of yellow fever caused the federal and state governments to flee Philadelphia and killed about five thousand residents. The disease continued to plague summers in Philadelphia until the beginning of the nineteenth century.

This 1820 political cartoon lampoons a real incident in which members of the New York Board of Health incorrectly diagnosed a heavily intoxicated man from Philadelphia with yellow fever. The doctors in the cartoon ignore the African American woman insisting that the man is just drunk. It further implies that Philadelphia's more-experienced doctors would have not made the mistake.

The Lazaretto

Library of Congress

One of the city's earliest methods of controlling large epidemics was to quarantine the ill to prevent them from infecting others. Built in 1799 in response to the devastating yellow fever epidemics that plagued Philadelphia, the Lazaretto Quarantine Station in Tinicum Township, Delaware County, is the oldest surviving quarantine hospital in the Western Hemisphere. All passenger ships entering Philadelphia were required to dock at the Lazaretto pending a health inspection of passengers.

A precipitous rise in immigration through the Lazaretto occurred in the 1870s; between 1873 and 1870, the number of passengers inspected jumped from four thousand to thirty thousand. At the time, a devastating cholera epidemic was spreading through much of Europe, including the United Kingdom, and Philadelphians feared the disease would spread from the quarantine hospital to the rest of the city. In response, a new quarantine station was built at Marcus Hook, Pennsylvania, about twenty miles south of Philadelphia. The Lazaretto closed in 1895. The building was added to the National Register of Historic Places in 1972 and remains standing.

The Kind of Assisted Emigrant We Cannot Afford to Admit

Historical Society of Pennsylvania

From its origins in the Ganges River Valley of India, cholera spread rapidly across Europe beginning in 1829 and was first identified in the United States in 1832. It was likely introduced by immigrants from the United Kingdom. Cholera, like many of the epidemic diseases that afflicted Philadelphians, is spread by water contaminated with fecal matter.

In this political cartoon from New York, the disease is depicted as a grotesque figure with a scythe on the prow of a ship flying British flags, being held back by the Board of Health. The caption reads, “The kind of 'assisted emigrant' we cannot afford to admit.” In Philadelphia, cholera reached epidemic levels in July 1832 and again in 1849, both times claiming about a thousand lives. This number, far less than the devastation in other North American cities like Montreal, is attributed to the cleanliness of the drinking water in Philadelphia's Fairmount Reservoir. Minor cholera outbreaks continued throughout the nineteenth century. With the filtration of Philadelphia's water supply in the early twentieth century, the disease was largely eradicated.

Spit Spreads Death

Special Collections Research Center, Temple University Libraries

The “Spanish flu” pandemic of 1918-19 was one of the most devastating epidemics in history. The disease appeared suddenly in January 1918 and spread rapidly across the globe. In August, the disease mutated to a more virulent and deadly form. It reached Philadelphia in September 1918, unfortunately coinciding with a war bonds parade. The virus swept through the crowd, infecting thousands on the first day. Philadelphia's outbreak grew to be the worst in the nation, leaving between thirteen thousand and nineteen thousand people dead in just six months. This photograph from the height of the epidemic shows a sign from the Board of Health's campaign to stop people from spitting on the sidewalks. Violators caught spitting were fined $2.50 or even arrested for their crime. City Hall rises in the background.

Works Progress Administration Public Health Campaign

Library of Congress

Now curable by a brief round of antibiotics, syphilis was once a devastating and disfiguring disease that plagued Philadelphia. Syphilis can cause severe physical disfiguration or neurological symptoms including dementia if left untreated.

Before modern drugs were developed, syphilis was treated with mercury in doses high enough to cause heavy metal toxicity. The first antibacterial treatment for syphilis was developed in the early twentieth century. Derived from arsenic, it was sometimes combined with intentionally inoculating the patient with malaria to cause a high fever.

This Works Progress Administration poster urging people to seek treatment was released in 1941, one year before the antibiotic penicillin became widely available to treat the infection.

Children with Polio Support the March of Dimes, 1950

Special Collections Research Center, Temple University Libraries

Poliomyelitis is a disease spread through oral contact with fecal matter contaminated by the poliovirus. While most cases are asymptomatic, a small percentage of patients develop a paralytic form. Polio did not reach epidemic levels until the first half of the twentieth century.

Ironically, Philadelphia's sanitation initiatives of the late nineteenth and early twentieth centuries were likely to blame for the dramatic rise in cases. Children were exposed to the virus as infants prior to this and developed a lifelong immunity to future infection. With improved sanitation, exposure came later in life when it was more likely to progress to the paralytic form of the disease.

This 1950 photograph shows polio-afflicted children in Philadelphia meeting with the chairman of the city's March of Dimes organization. The polio epidemic in the United States peaked in 1952 with approximately sixty thousand new cases diagnosed. That same year, Dr. Jonas Salk and others at the University of Pittsburgh developed the first effective poliovirus vaccine. It became available to the public in 1955. In 1979, the Centers for Disease Control declared the poliovirus eradicated in the United States.

Legionnaires' Disease Symposium

Special Collections Research Center, Temple University Libraries

In July 1976, a mysterious new disease struck members of the American Legion who had gathered in Philadelphia. Coinciding with the Bicentennial Celebration, the American Legion chose to hold its annual convention at the Bellevue-Stratford Hotel at Broad and Walnut Streets.

In the weeks following the convention, twenty-nine attendees died of an illness that baffled epidemiologists for nearly six months and forced the Bellevue-Stratford Hotel to close its doors. Finally, an until-then-unknown genus of bacteria, dubbed Legionella, was discovered in the large air conditioning system of the Bellevue-Stratford. Legionella infects the lungs when it is aerosolized and inhaled, and causes an atypical form of pneumonia; it cannot be spread person-to-person. Today, it is treated with antibiotics.

ACT-UP Philadelphia Protest

John J. Wilcox LGBT Archives of Philadelphia

In the late 1970s, an alarming new epidemic appeared. Patients displayed symptoms of uncommon diseases, such as the opportunistic fungal infection Pneumocystis jirovecii pneumonia and a rare cancer, Karposi's sarcoma. These diseases prey on the immune-compromised. Physicians confirmed the first diagnosed cases in Philadelphia in September 1981. The virus that caused the syndrome was first identified in 1983 and dubbed the Human Immunodeficiency Virus (HIV); the final stages of infection were named the Acquired Immunodeficiency Syndrome (AIDS).

At first, the disease seemed to affect gay men almost exclusively until it was discovered that it also infected heterosexuals and intravenous drug users. Many believed that the stigma of the disease's association with homosexuality caused the administration of Ronald Reagan to hesitate in addressing the crisis. The gay community was also skeptical of the early reports of the disease and failed to heed the warnings of public health officials.

The AIDS Coalition to Unleash Power (ACT UP) was formed in New York in 1987 to combat the stigma of AIDS and urge the government to react to the epidemic. Soon, a local branch formed in Philadelphia. In this photo from 1991, an ACT UP protest unfolds during a 1991 visit by President George H.W. Bush. In the 1990s, antiretroviral therapies were developed that prevent the virus from replicating. Today, life expectancy for HIV-positive individuals following an antiretroviral plan is nearly the same as the HIV-negative population.

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Related Reading

Alewitz, Sam. “Filthy Dirty:” A Social History of Unsanitary Philadelphia in the Late Nineteenth Century. New York: Garland Publishing Inc., 1989.

Cheney, Rose A. “Seasonal Aspects of Infant and Childhood Mortality: Philadelphia, 1865–1920.” Journal of Interdisciplinary History 14 (Winter 1984): 561–85.

Condran, Gretchen A., Henry Williams, and Rose A. Cheney, “The Decline in Mortality in Philadelphia from 1870 to 1930: The Role of Municipal Services” Pennsylvania Magazine of History and Biography 108 (April 1984): 153–77.

Estes, J. Worth, and Billy G. Smith, eds. A Melancholy Scene of Devastation: The Public Response to the 1793 Philadelphia Yellow Fever Epidemic. Canton, Mass.: Science History Publications, 2013.

Finger, Simon. The Contagious City: The Politics of Public Health in Early Philadelphia. Ithaca, N.Y.: Cornell University Press, 2012.

Galishoff, Stuart. Newark, the Nation’s Unhealthiest City, 1832–1895. New Brunswick, N.J.: Rutgers University Press, 1988.

Higgins, Jim. “B. Franklin Royer: A Half Century in Public Health” Pennsylvania History 81 (Spring 2014): 169–206.

McCarthy, Michael P. Typhoid and the Politics of Public Health in Nineteenth-Century Philadelphia. Philadelphia: American Philosophical Society, 1987.

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