Learn to recognize the symptoms
The smallpox pandemic that swept across the world in the 1600s arrived in North America in 1633, beginning with the arrival of European settlers in the northeastern region of the continent. A dreaded disease, it decimated the Native American population as it spread west.
Within a few months, 10% of Philadelphia's population was dead. Thousands more had fled the city to avoid the scourge. Yellow fever causes yellowing of the skin, fever, and bloody vomiting. It's believed the disease took hold in the city after refugees fleeing a yellow fever epidemic in the Caribbean sailed into Philadelphia, carrying the virus with them.
The United States was ravaged by three separate waves of cholera, between 1832 and 1866. The first epidemic occurred as a result of an immigrant ship landing at Quebec in Canada with cases of Asiatic cholera aboard.
The disease quickly spread south into the United States, with New York City first to feel the impact. Overall, between 5-10% of the total population of America died in large cities. Cholera is an acute diarrheal infection usually caused by contaminated water. Immediate treatment is crucial because cholera can cause death.
A little over 20 years later, the United States recorded another epidemic, this time scarlet fever, which also came in waves. The initial outbreak was centered on Massachusetts, where over a 12-month period some 2,000 people died.
One of the most infamous typhoid epidemics in the United States was that which broke out in 1906 in New York City. Patient zero was identified as Mary Mallon, known as "Typhoid Mary."
Typhoid Mary spread the bacterial infection to at least 120 New Yorkers during her time as a cook on an estate and in a hospital unit, though she herself was immune to the disease. According to the Centers for Disease Control and Prevention (CDC), 13,160 people succumbed to typhoid in 1906 and 12,670 died in 1907.
The influenza pandemic of 1918–1919 remains the most severe influenza outbreak of the 20th century, and ranks among the most devastating pandemics in human history.
The United States lost 675,000 people to the Spanish flu in 1918. To put that figure into perspective, that's more casualties than both world wars, the Korean War, and the Vietnam War combined.
Famously in 1925, the remote town of Nome in Alaska ran out of antitoxin used to treat the disease. Batches of emergency medication were dispatched mid-winter by dogsled in an emergency delivery operation known as the serum run.
During the first half of the 1920s, an estimated 100,000 to 200,000 diphtheria cases and 13,000 to 15,000 related deaths occurred in the United States. Diphtheria is a potentially fatal contagious bacterial infection that mainly affects the nose and throat.
The first major outbreak of polio in the United States occurred in 1916 and was centered on New York City. Polio is a highly infectious disease caused by a virus that mainly affects nerves in the spinal cord or brain stem. It can cause paralysis in a matter of hours.
In the early 20th century, the disease was little understood. However, by the time the second epidemic swept the country in 1952, health experts were busily working on a vaccine. Of the 57,628 reported cases in 1952, there were 3,145 deaths. In 1955, a vaccine was approved and quickly adopted throughout the world.
The 1957 flu pandemic was caused by the influenza H2N2 virus, which originated in birds and was first reported in Singapore in February of that year. By the summer of 1957, H2N2 had reached American soil.
Sometimes referred to as "bird flu," the virus was caught early in the United States thanks to the availability of a vaccine developed in 1942. Despite this, H2N2 still managed to claim 116,000 lives across the nation.
Measles infects the respiratory tract and then spreads throughout the body. Symptoms include a high fever, cough, runny nose, and a rash all over the body. Measles elimination efforts in the Americas started in earnest in 1991 and those nine to 15 years of age in the region were vaccinated with an additional dose of measles vaccine.
Advances in medical science throughout the second half of the 20th century helped combat a number of previously fatal diseases. Unfortunately, the failure to vaccinate preschool-aged children at appropriate ages in the early 1980s led to a second measles outbreak in the United States, according to the CDC.
In 1993, reports of a widespread outbreak of acute watery diarrhea among the residents of Milwaukee made national headlines. Further investigation identified cryptosporidiosis as the culprit.
The H1N1 influenza virus first appeared in Mexico and the United States in March and April 2009. It quickly spread across the US and then the world, with the media referring to the outbreak as "swine flu."
From April 2009 to April 2010, the CDC estimated there were 60 million cases of H1N1 in the US, resulting in 274,304 hospitalizations and 12,469 deaths.
Pertussis, known as whooping cough, is a highly contagious respiratory tract infection. The whooping cough vaccine is routinely given as part of the 6-in-1 vaccine—diphtheria, tetanus, pertussis, polio, haemophilus influenzae type b (Hib), and hepatitis B. Infants too young for vaccination have the highest risk for life-threatening cases.
During the first outbreak of pertussis in the United States in 2010, 13 infants died. During the next significant outbreak in 2014, 10 toddlers succumbed to the condition, incidentally one of the most commonly occurring diseases in the country.
The first reported cases of HIV (human immunodeficiency virus) appeared in the United States in 1981. Soon evolving into a nationwide epidemic, HIV damages the immune system so that the body is less able to fight infection and disease. Pictured is the AIDS Memorial Quilt shown for the first time on the National Mall in Washington, D.C.
AIDS is the final stage of HIV. The CDC reports over 565,000 people have died of AIDS-related causes in the US since 1981. There's no cure for HIV/AIDS, but medicines can control the infection and keep the disease from getting worse.
COVID-19 is a contagious disease caused by the coronavirus SARS-CoV-2. It was first detected in Wuhan City, China, in late 2019. In March 2020, after more than 118,000 cases in 114 countries and 4,291 deaths, the WHO declared COVID-19 a pandemic.
As of April 2023, the number of both confirmed and presumptive positive cases of the COVID-19 disease reported in the United States had reached over 104 million, with over 1.1 million deaths reported among these cases, according to latest figures published by Statista.
Sources: (National Institutes of Health) (American Society for Microbiology) (CDC) (Pan American Health Organization) (World Health Organization) (Statista)
See also: Five years after the COVID outbreak, questions remain unanswered
Smallpox, the symptoms of which included high fever, severe back pain, chills, vomiting, and rashes, lingered. Repeated outbreaks recorded in 1721, 1752, 1764, and 1775 were particularly devasting. In 1721 alone, well over 6,000 cases were reported out of a Boston population of 11,000. Around 850 people died from the disease.
Most of the victims were children under the age of 16. But adults who were in contact with their sick offspring were also at increased risk. The first signs of scarlet fever can be flu-like symptoms, including a high temperature, sore throat, and swollen neck glands. The telltale rash appears 12 to 48 hours later.
Cryptosporidiosis is caused by cryptosporidium, a nasty parasite found in the intestines of infected humans and animals and is passed out in their feces. A water treatment plant became contaminated with cryptosporidiosis, leading to 403,000 people falling ill and 69 dying. The incident remains the largest waterborne outbreak in United States history.
The summer of 1793 in Philadelphia was especially hot and humid. The rancid swamps surrounding the city were alive with the Aedes aegypti mosquito, a known vector of several viruses including yellow fever.
The US is no stranger to epidemics. As far back as the 1600s, for example, Americans were falling victim to smallpox. Since then, several epidemics have visited the nation, some claiming thousands of lives. But what are these dreadful diseases, and how did they take hold?
Click through the following gallery for a look back at the worst outbreaks in US history.
The worst outbreaks of disease in US history
Diseases and illnesses that blighted the United States
HEALTH History
The US is no stranger to epidemics. As far back as the 1600s, for example, Americans were falling victim to smallpox. Since then, several epidemics have visited the nation, some claiming thousands of lives. But what are these dreadful diseases, and how did they take hold?
Click through the following gallery for a look back at the worst outbreaks in US history.