This is a list of the largest known

epidemic An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time. Epidemics of infectious d ...

s and

pandemic A pandemic () is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. A widespread endemic disease with a stable number of i ...

s caused by an

infectious disease An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable d ...

. Widespread

non-communicable diseases A non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another. NCDs include Parkinson's disease, autoimmune diseases, strokes, most heart diseases, most cancers, diabetes, chronic kidney disease, oste ...

such as

cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, ...

and

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bl ...

are not included. An epidemic is the rapid spread of

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

to a large number of people in a given population within a short period of time; in meningococcal infections, an

attack rate In epidemiology, the attack rate is the proportion of an at-risk population that contracts the disease during a specified time interval. It is used in hypothetical predictions and during actual outbreaks of disease. An at-risk population is defined ...

in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic. Due to the long time spans, the first plague pandemic (6th century – 8th century) and the

second plague pandemic The second plague pandemic was a major series of epidemics of plague that started with the Black Death, which reached Europe in 1348 and killed up to half of the population of Eurasia in the next four years. Although the plague died out in most pla ...

(14th century – early 19th century) are shown by individual outbreaks, such as the

Plague of Justinian The plague of Justinian or Justinianic plague (541–549 AD) was the first recorded major outbreak of the first plague pandemic, the first Old World pandemic of plague, the contagious disease caused by the bacterium ''Yersinia pestis''. The d ...

(first pandemic) and the Black Death (second pandemic).

Major epidemics and pandemics

By death toll

Extant epidemics are in boldface. For a given epidemic, the average of its estimated death toll range is used for ranking. If the death toll averages of two or more epidemics are equal, then the smaller the range, the higher the rank. For the historical records of major changes in the world population, see

world population In demographics, the world population is the total number of humans currently living. It was estimated by the United Nations to have exceeded 8 billion in November 2022. It took over 200,000 years of human prehistory and human history, ...

Depopulation of the Americas

Not included in the above table are many waves of deadly diseases brought by Europeans to the Americas and Caribbean. Western Hemisphere populations were decimated mostly by

smallpox Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) ce ...

, but also

typhus Typhus, also known as typhus fever, is a group of infectious diseases that include epidemic typhus, scrub typhus, and murine typhus. Common symptoms include fever, headache, and a rash. Typically these begin one to two weeks after exposure. ...

, measles,

influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptom ...

bubonic plague Bubonic plague is one of three types of plague caused by the plague bacterium ('' Yersinia pestis''). One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and vomiting, as ...

, cholera,

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or deat ...

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ...

mumps MUMPS ("Massachusetts General Hospital Utility Multi-Programming System"), or M, is an imperative, high-level programming language with an integrated transaction processing key–value database. It was originally developed at Massachusetts Gen ...

yellow fever Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In ...

, and

pertussis Whooping cough, also known as pertussis or the 100-day cough, is a highly contagious bacterial disease. Initial symptoms are usually similar to those of the common cold with a runny nose, fever, and mild cough, but these are followed by two o ...

. The lack of written records in many places and the destruction of many native societies by disease, war, and colonization make estimates uncertain. Deaths probably numbered in the tens or perhaps over a hundred million, with perhaps 90% of the population dead in the worst-hit areas. Lack of scientific knowledge about microorganisms and lack of surviving medical records for many areas makes attribution of specific numbers to specific diseases uncertain.

Infectious diseases with high prevalence

There have been various major infectious diseases with high prevalence worldwide, but they are currently not listed in the above table as epidemics/pandemics due to the lack of definite data, such as time span and death toll. *

Tuberculosis Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ...

(TB) became

in Europe in the 18th and 19th century, showing a seasonal pattern, and is still taking place globally. The

morbidity A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that ...

and mortality of TB and

HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...

have been closely linked, known as "TB/HIV syndemic". According to the

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...

, approximately 10 million new TB infections occur every year, and 1.5 million people die from it each year – making it the world's top infectious killer (before

COVID-19 pandemic The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identified ...

). However, there is a lack of sources which describe major TB epidemics with definite time spans and death tolls. * According to the World Health Organization, as of 2019 there are about 296 million people living with chronic

hepatitis B Hepatitis B is an infectious disease caused by the '' Hepatitis B virus'' (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection. Many people have no symptoms during an initial infection. F ...

, with 1.5 million new infections each year. In 2019, hepatitis B caused about 820,000 deaths, mostly from

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

and

hepatocellular carcinoma Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is currently the most common cause of death in people with cirrhosis. HCC is the third leading cause of cancer-related deaths worldwide. It occurs in th ...

(primary

liver cancer Liver cancer (also known as hepatic cancer, primary hepatic cancer, or primary hepatic malignancy) is cancer that starts in the liver. Liver cancer can be primary (starts in liver) or secondary (meaning cancer which has spread from elsewhere to th ...

). In many places of Asia and Africa, hepatitis B has become

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

. In addition, a person is sometimes infected with both hepatitis B virus (HBV) and HIV, and this population (about 2.7 million) accounts for about 1% of the total HBV infections. * According to the World Health Organization, there are approximately 58 million people with chronic

hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, ...

, with about 1.5 million new infections occurring per year. In 2019, approximately 290,000 people died from the disease, mostly from

and

(primary

). There have been many hepatitis C virus (HCV) epidemics in history.

Chronology

Events in are ongoing.

Explanatory notes

References

External links

* {{DEFAULTSORT:Epidemics, List Of Disease outbreaks Globalization-related lists Lists by death toll Lists of disasters