The Black Death was the largest and deadliest pandemic of Yersinia pestis recorded in human history, and likely the most infamous individual pandemic ever documented. The plague originated in the Eurasian Steppes, before moving with Mongol hordes to the Black Sea, where it was then brought by Italian merchants to the Mediterranean. From here, the Black Death then spread to almost all corners of Europe, the Middle East, and North Africa. While it was never endemic to these regions, it was constantly re-introduced via trade routes from Asia (such as the Silk Road), and plague was present in Western Europe until the seventeenth century, and the other regions until the nineteenth century. Impact on Europe In Europe, the major port cities and metropolitan areas were hit the hardest. The plague spread through south-western Europe, following the arrival of Italian galleys in Sicily, Genoa, Venice, and Marseilles, at the beginning of 1347. It is claimed that Venice, Florence, and Siena lost up to two thirds of their total population during epidemic's peak, while London, which was hit in 1348, is said to have lost at least half of its population. The plague then made its way around the west of Europe, and arrived in Germany and Scandinavia in 1348, before travelling along the Baltic coast to Russia by 1351 (although data relating to the death tolls east of Germany is scarce). Some areas of Europe remained untouched by the plague for decades; for example, plague did not arrive in Iceland until 1402, however it swept across the island with devastating effect, causing the population to drop from 120,000 to 40,000 within two years. Reliability While the Black Death affected three continents, there is little recorded evidence of its impact outside of Southern or Western Europe. In Europe, however, many sources conflict and contrast with one another, often giving death tolls exceeding the estimated population at the time (such as London, where the death toll is said to be three times larger than the total population). Therefore, the precise death tolls remain uncertain, and any figures given should be treated tentatively.

Even in 2021, bubonic plague continues to exist in nature, and there are generally a few thousand human cases per year. Going back to the beginning of the 20th century, it is estimated that there were roughly one million cases per year in 1907. Within two decades, this number had fallen below one fifth of this level to 170,000 cases per year in the 1920s, and in the 1940s it was just over 20,000 per year. By the mid-20th century, it had fallen below 5,000 cases per year, but the rapid decrease in cases observed in the first half of the 1900s did not continue through the second half of the century. Even in 2019, there was one case of plague recorded in the United States. How infection occurs Yersinia pestis is the bacteria that causes the plague virus, and it is most commonly spread by rats and their fleas. The disease survives by fleas infecting rats, which in turn infect other fleas; the majority of rats survive the disease, which facilitates its spread; this is known as the "enzootic cycle ". Interestingly, the disease is usually fatal for the fleas, as it blocks their "stomachs" and causes them to starve; as the fleas get hungrier, they attempt to feed on more hosts, spreading the disease more rapidly. When the rats die, the parasitic fleas then search for a new host, which means that other animals (particularly mammals) are susceptible to this virus. While rat fleas can not survive on other hosts for very long, they can infect other (including human) fleas with the virus. The most common way for humans to contract the plague however, is when a rat flea bites its human host; during this process the flea simultaneously regurgitates Yersinia pestis bacteria into the wound, and this causes bubonic plague. Humans can then spread the disease among one another by coming into contact with the infected tissue or fluids of an infected person, or from the transfer of fleas. Continued existence of the plague Plague is extremely difficult to eradicate in nature, as rodent communities in the wild provide natural reservoirs for the disease to spread. In previous centuries, rats had much more frequent contact with humans for a variety of reasons; houses were more often made of wood (which made infestations easier), public spaces were much dirtier, and the presence of rats was tolerated more. As the understanding of epidemiology grew in the 20th century, this greatly reduced the frequency of plague in human populations. Unlike human diseases such as smallpox, which was eradicated through vaccination and other medical advancements, basic sanitation and the extermination of rats have been the driving force behind the decline of plague.

Although the Black Death peaked in Europe between 1348 and 1351, plague was almost always present in Britain for the next four centuries. In most years, plague was a dormant threat that affected very few people, and diseases such as smallpox and influenza were much more widespread; however, bubonic plague was prone to outbreaks that could decimate populations in a few short years. In London, plague outbreaks occurred every few decades, usually with death tolls in the tens of thousands. The duration and severity of these epidemics varied, sometimes having high death tolls but subsiding quickly, while others had relatively lower death tolls but could last for a number of years. As London's population and density also grew drastically during this period, plague affected the city differently in the sixteenth and seventeenth centuries. Great Plague of London The final major plague epidemic observed in Britain took place in 1665 and 1666. It became known as the "Great Plague" as it was the last of its kind in Britain, and its death toll eclipsed all other epidemics in the preceding century (although it was much smaller than that of the Black Death). The plague lasted for eighteen months, and had a reported death toll of more than 70,000 in this time; although modern historians estimate that the actual death toll exceeded 100,000. At its peak in September 1665, it is reported that there were more than 7,000 deaths per week, although this may have also been much higher due to the limited records kept at the time. Another reason for the lack of accurate records relating to this epidemic is because of the Great Fire of London in 1666. The fire started on September 02. 1666, and destroyed almost all of the city within the walls, leaving thousands homeless. Historians continue to debate the fire's significance, some citing that it destroyed the unsanitary dwellings where infected rats lived and drove them from the city, while others claim that the timings were purely coincidental and that the epidemic had already begun to subside in February.

The Plague of Justinian was an outbreak of bubonic plague that ravaged the Mediterranean and its surrounding area, between 541 and 767CE. It was likely the first major outbreak of bubonic plague in Europe, and possibly the earliest pandemic to have been recorded reliably and with relative accuracy. Contemporary scholars described the symptoms and effects of the disease in detail, and these matched descriptions of the Black Death and Third Pandemic, leading most historians to believe that this was bubonic plague. It was also assumed that the plague originated in sub-Saharan Africa, before making its way along the Nile to Egypt, and then across the Mediterranean to Constantinople. In 2013, scientists were able to confirm that Justinian's Plague was in fact Yersinia pestis (the bacteria which causes bubonic plague), and recent theories suggest that the plague originated in the Eurasian Steppes, where the Black Death and Third Pandemic are also thought to have originated from, and that it was brought to Europe by the Hunnic Tribes of the sixth century. Plague of Justinian The pandemic itself takes its name from Emperor Justinian I, who ruled the Byzantine Empire (or Eastern Roman Empire) at the time of the outbreak, and who actually contracted the disease (although he survived). Reports suggest that Constantinople was the hardest hit city during the pandemic, and saw upwards of five thousand deaths per day during the most severe months. There are a multitude of sources with differing estimates for the plague's death toll, with most ranging between 25 and 100 million. Until recently, scholars assumed that the plague killed between one third and 40 percent of the world's population, with populations in infected regions declining by up to 25 percent in early years, and up to 60 percent over two centuries. The plague was felt strongest during the initial outbreak in Constantinople, however it remained in Europe for over two centuries, with the last reported cases in 767. Pre-2019 sources vary in their estimates, with some suggesting that up to half of the world's population died in the pandemic, while others state that it was just a quarter of the Mediterranean or European population; however most of them agree that the death toll was in the tens of millions. Historians have also argued about the plague's role in the fall of the Roman Empire, with opinions ranging from "fundamental" to "coincidental", although new evidence is more aligned with the latter theories. Challenging theories As with the recent studies which propose a different origin for the disease, one study conducted by researchers in Princeton and Jerusalem calls into question the accuracy of the death tolls estimated by historians in the 19th and 20th centuries. In 2019, L. Mordechai and M. Eisenberg published a series of papers suggesting that, although the plague devastated Constantinople, it did not have the same impact as the Black Death. The researchers argue that modern historians have taken a maximalist approach to the death tolls of the pandemic, and have applied the same models of distribution to Justinian's Plague as they believe occurred during the Black Death; however there is little evidence to support this. They examine the content and number of contemporary texts, as well archaeological, agricultural and genetic evidence which shows that the plague did spread across Europe, but did not seem to cause the same societal upheaval as the Black Death. It is likely that there will be further investigation into this outbreak in the following years, which may shed more light on the scale of this pandemic.

Legend: Year: the demography of the 6 "years of plague" is in bold characters and the column immediately at the left indicates, for each epidemic, the demography of the previous year. Mortality rate: crude mortality rate (as per thousand) evaluated for the heads of households; reflects the global damage of an epidemic S1 Fig. Survivors: number of surviving heads of households after exclusion of those not corresponding to individuals S2 Text. Single deaths: number of households with one reported death, whether or not of the head of household. Multiple deaths: number of deaths in the households where the concomitant death of several persons is reported S4 Text. Total deaths: total number of deaths taken into account for analysis (sum of lines 4 and 5). Death rate: ratio between the number of reported deaths and the sum of reported deaths and survivors (as percent); does not reflect the mortality of the year, but allows comparisons between groups of individuals or areas during the same year. Grouped deaths: households where multiple deaths took place, or households contiguous or separated by a single survivor in the register.Demography of the "years of plague" and of the previous years.

The Plague of Justinian was the first major bubonic plague pandemic recorded in Europe, and was the first pandemic to ever be described or documented with any relative reliability. The plague takes its name from Emperor Justinian I, who ruled the Byzantine Empire (Eastern Roman Empire) at the time of the outbreak. The Byzantine capital of Constantinople (also known then as Byzantium, and Istanbul today) was the hardest hit city during the pandemic, and where the majority of sources are from. Until recently, it was only assumed that the outbreak was bubonic plague, due to the symptoms described by contemporary historians, but scientists were able to confirm that it was in fact Yersinia pestis (the bacterium that causes plague) in 2013. Constantinople overwhelmed It is thought that the plague was brought to Constantinople by Egyptian grain merchants, although a recent theory suggests it was brought from the Eurasian Steppes (from where Yersinia pestis originates) to Europe by Hunnic tribes. While the exact origins of the plague remain unclear, it is estimated that up to 300,000 people died in Constantinople in the first year of the outbreak. Contemporary sources claim that there were approximately 5,000 deaths in the city every day at the height of the pandemic, even reaching highs of 10,000 on some days. Constantinople outbreak was unique A 2019 study, conducted by researchers from Jerusalem and Princeton raises some important questions about the scale of the outbreak across Europe. They dispute the claim by some modern historians that this pandemic killed up to half of the population of the Mediterranean (or that it was instrumental to the collapse of the Eastern Roman Empire), instead suggesting that the scale of the outbreak in Constantinople was unique to that city. They use a variety of literary, archeological, and scientific sources to show that the plague was unlikely to have reached this magnitude across other cities at the time, nor did it spread in the same way that the Black Death did six centuries later. While future studies are likely to provide further insight into these theories, it is important to remember this contrasting hypothesis when studying pre-2019 sources.

Bubonic plague was a constant threat to Afro-Eurasian populations during the Second Plague pandemic. This pandemic arrived in Europe as the Black death in 1347, and although it never became endemic, it was constantly re-introduced to the continent over the next four centuries. By the late seventeenth century, most regions of Europe had recorded their final epidemics (but not necessarily the final cases), and it eventually subsided in the mid-nineteenth century. The death tolls due to plague were relatively low in most years, however, when epidemics appeared they could often decimate populations within a few short years, and lead to mass evacuations of major cities (such as in London in 1665). Plague in Russia Of the sample epidemics shown here, the two largest cases were in Russia; a region where plague outbreaks were much more frequent than in other parts of Europe. The reason for this was because plague would spread along the Volga river, after being brought to the Caspian Sea by fishermen from the Eurasian Steppes (where the plague bacteria Yersinia pestis is thought to originate). Between these two epidemics, it is estimated that Russia lost over half a million people. The epidemic of 1709, which spread across Northern Europe during the Great Northern War, saw a reported 150,000 deaths across the Russian Empire. The plague epidemic of 1771 in Russia saw the deaths of approximately 60,000 in the capital city, and as many as 300,000 in the surrounding region. In Moscow, the government's attempts to contain the outbreak resulted in a riot by the citizens, and the aftermath saw significant socio-political upheaval in the city and beyond.

A Comprehensive History of Major Disease Outbreaks

Tracing the Past to Prevent the Future

About this dataset

This dataset provides a comprehensive record of major disease outbreaks throughout history. It includes information on the disease, the death toll, the date and location of the outbreak, and the global and regional population lost.

Disease outbreaks are a major public health issue that can have devastating consequences. This dataset can help us better understand how these diseases spread and how to prevent them in the future. By studying this data, we can learn from past mistakes and take steps to avoid repeating them

How to use the dataset

This dataset provides a comprehensive record of major disease outbreaks throughout history. It includes information on the disease, the death toll, the date and location of the outbreak, and the global and regional population lost.

To use this dataset, simply download it as a CSV file and import it into your favourite data analysis software. From there, you can begin to explore the data and understand more about how these diseases have affected people throughout history

Research Ideas

• This dataset can be used to study the history of major disease outbreaks and the effects they have had on global and regional populations.

• This dataset can be used to predict future disease outbreaks by identifying patterns and trends in past outbreaks.

• This dataset can be used to develop better strategies for responding to and preventing future disease outbreaks

Acknowledgements

The dataset was compiled by the Centers for Disease Control and Prevention (CDC)

License

License: CC0 1.0 Universal (CC0 1.0) - Public Domain Dedication No Copyright - You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission. See Other Information.

Columns

File: df_16.csv

File: df_26.csv

File: df_20.csv

File: df_18.csv

File: df_25.csv

File: df_11.csv | Column name | Description | |:------------------------------------------------|:---------------------------------------------------------------------------------------------------------------------| | vteNatural disasters – list by death toll | This column lists natural disasters by death toll. (Categorical) | | vteNatural disasters – list by death toll.1 | This column lists natural disasters by death toll and provides additional information on the disaster. (Categorical) |

File: df_1.csv | Column name | Description | |:-----------------------------|:----------------------------------------------------------------------------------| | Rank | The rank of the disease outbreak. (Numeric) | | Disease | The name of the disease. (String) | | Death toll | The number of deaths caused by the disease outbreak. (Numeric) | | Global population lost | The percentage of the global population lost to the disease outbreak. (Numeric) | | Regional population lost | The percentage of the regional population lost to the disease outbreak. (Numeric) | | Date | The date of the disease outbreak. (Date) | | Location | The location of the disease outbreak. (String) |

File: df_4.csv

File: df_21.csv

File: df_17.csv

File: df_24.csv

File: df_9.csv

File: df_13.csv

File: df_14.csv

File: df_22.csv

File: df_15.csv

File: df_10.csv

File: df_3.csv

File: df_19.csv

File: df_2.csv | Column name | Description | |:--------------------------|:--------------------------------------------------------------------| | Date | The date of the disease outbreak. (Date) | | Location | The location of the disease outbreak. (String) | | Disease | The name of the disease. (String) | | Event | A description of the disease outbreak. (String) ...

Legend: Line 1: Grouped death clusters (or Dijon). Line 2: total number of households (deaths and survivors). Line 3: number of deaths (grouped and non-grouped). Line 4: result of the statistical test comparing the cluster(s) with the rest of the city. Line 5: death rate as percent. Column 2: pooled data from the 2 clusters of higher grouped death relative risk. Column 3: data from the cluster of lower grouped death relative risk. Column 4: data for the whole city. ND: not done. For each cluster, data of the control (rest of the city) can be computed by subtraction from the data of the whole city.Deaths in the mortality-based clusters in 1440.

For most years between 1603 and 1680, plague was responsible for less than one percent of all deaths in London. However, when epidemics did break out they could often be responsible for more than half of all deaths in the city during those years, even going as high as 86 percent in 1603. This was the highest share of deaths due to plague in London in the given time period, although the final epidemic shown in the graph is remembered as the most devastating, taking almost 70,000 lives during the Great Plague of London in 1665.

ObjectivesThis work was designed to adapt Geographical Information System-based spatial analysis to the study of historical epidemics. We mapped "plague" deaths during three epidemics of the early 15th century, analyzed spatial distributions by applying the Kulldorff's method, and determined their relationships with the distribution of socio-professional categories in the city of Dijon.Materials and MethodsOur study was based on a database including 50 annual tax registers (established from 1376 to 1447) indicating deaths and survivors among the heads of households, their home location, tax level and profession. The households of the deceased and survivors during 6 years with excess mortality were individually located on a georeferenced medieval map, established by taking advantage of the preserved geography of the historical center of Dijon. We searched for clusters of heads of households characterized by shared tax levels (high-tax payers, the upper decile; low-tax payers, the half charged at the minimum level) or professional activities and for clusters of differential mortality.ResultsHigh-tax payers were preferentially in the northern intramural part, as well as most wealthy or specialized professionals, whereas low-tax payers were preferentially in the southern part. During two epidemics, in 1400–1401 and 1428, areas of higher mortality were found in the northern part whereas areas of lower mortality were in the southern one. A high concentration of housing and the proximity to food stocks were common features of the most affected areas, creating suitable conditions for rats to pullulate. A third epidemic, lasting from 1438 to 1440 had a different and evolving geography: cases were initially concentrated around the southern gate, at the confluence of three rivers, they were then diffuse, and ended with residual foci of deaths in the northern suburb.ConclusionUsing a selected historical source, we designed an approach allowing spatial analysis of urban medieval epidemics. Our results fit with the view that the 1400–1401 epidemic was a Black Death recurrence. They suggest that this was also the case in 1428, whereas in 1438–1440 a different, possibly waterborne, disease was involved.

The Third Plague Epidemic began in the mid-1800s in Yunnan, China, (an area that is still a natural reservoir for the Yersinia pestis bacteria) and had a huge death toll across Asia in the next century. While plague was confined to the Yunnan region for some decades, the mass displacement and social upheaval caused by the Taiping Rebellion saw millions flee the area , bringing the disease to other parts of the country. A plague epidemic then emerged in British-controlled Hong Kong in 1894, where merchants then unknowingly transported infected rats to other parts of the empire along various trade routes. Arrival in Bombay The first Indian cases were reported in Bombay (present-day Mumbai), and the Bombay Presidency suffered more losses than any other region in India (although there were some individual years where the state of Punjab reported more deaths). As with most disease or famine outbreaks in the region, the British authorities were slow to react, and their eventual response was in many ways too late. In some cases authorities even facilitated the spread of the disease; with multiple accounts of the military forcing healthy people into quarantine camps, evicting and burning homes of the afflicted, or by using such excessive force that the public would refuse medical help. Spread in India Lack of understanding among the Indian public was also to their own detriment. Some religions in India forbid the killing of rats, while some people simply refused to acknowledge that they were sick. As the plague in Bombay spiraled out of control, many fled to other parts of the country, taking the plague with them. It is estimated that there were over one million deaths in India by 1902, and almost one million further deaths in 1903 alone. The first four months of 1904 also saw over half a million deaths, almost matching the entire total for 1902. Plague would remain endemic to India for the next few decades, and there are varying reports of up to 10 or 12 million total plague deaths in this time. The public health measures taken to combat the plague in the early 20th century would mark the beginnings of India's public health system, and some of the quarantine measures put in place by the colonial government were even used in 2020 during the outbreak of the COVID-19 pandemic.

The leading causes of death in Massachusetts are cancer, heart disease, unintentional injury, stroke, and chronic lower respiratory disease. These mortality rates tend to be higher for people of color; and Black residents have a higher premature mortality rate overall and Asian residents have a higher rate of mortality due to stroke.

Legend: Line 1: Mortality-based clusters (or Dijon). Line 2: Tax level group (Low: low-tax payers in 1399; Non-low: heads of households who were not low-tax payers in 1399). Line 3: total number of households (deaths and survivors) in 1400. Line 4: number of deaths in 1400. Line 5: result of the chi-square comparing the low-tax payers and the non-low-taxpayers. Line 6: death rates as percent. Columns 2 & 3: pooled data from the 3 clusters of higher grouped death relative risk in 1400. Columns 4 & 5: pooled data from the 2 clusters of lower grouped death relative risk in 1400. Columns 6 & 7: data for the whole city.Deaths (in 1400) of low-tax payers and non-low-tax payers of 1399.

The CDC WONDER Mortality - Underlying Cause of Death online database is a county-level national mortality and population database spanning the years since 1979 -2008. The number of deaths, crude death rates, age-adjusted death rates, standard errors and 95% confidence intervals for death rates can be obtained by place of residence (total U.S., Census region, Census division, state, and county), age group (including infant age groups), race (years 1979-1998: White, Black, and Other; years 1999-2008: American Indian or Alaska Native, Asian or Pacific Islander, Black or African American, and White), Hispanic origin (years 1979-1998: not available; years 1999-present: Hispanic or Latino, not Hispanic or Latino, Not Stated), gender, year of death, and underlying cause of death (years 1979-1998: 4-digit ICD-9 code and 72 cause-of-death recode; years 1999-present: 4-digit ICD-10 codes and 113 cause-of-death recode, as well as the Injury Mortality matrix classification for Intent and Mechanism), and urbanization level of residence (2006 NCHS urban-rural classification scheme for counties). The Compressed Mortality data are produced by the National Center for Health Statistics.

Legend: Line 1: Spatial entity. Line 2: total number of households (deaths and survivors). Line 3: number of deaths (grouped and non-grouped). Line 4: result of the chi-square comparing the group with the rest of the city. Line 5: death rate as percent. Column 2: data from the higher death relative risk cluster. Column 3: data from the higher grouped death relative risk cluster (mostly included in the previous one). Column 4: pooled data from the intramural parts of the northeastern Saint-Nicolas and Saint-Michel parishes (that largely corresponded to the higher death risk cluster of column 2). Column 5: data from the southwestern lower grouped death relative risk cluster. Column 6: data for the whole city. For each group, data of the control (rest of the city) can be computed by subtraction from the data of the whole city.Excess deaths in the northeast of intramural Dijon in 1428.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Each Maryland County's number of infant deaths and infant mortality rates by race in 2012 and 2013. Includes: a) Number of Infant Deaths of All Races - 2012 - b) Number of Infant Deaths of All Races - 2013 - c) Infant Mortality Rate of All Races Per 1 - 000 Live Births - 2012 - d) Infant Mortality Rate of All Races Per 1 - 000 Live Births - 2013 - e) White Infant Deaths - 2012 - f) White Infant Deaths - 2013 - g) White Infant Mortality Rate Per 1 - 000 Live Births 2012 - h) White Infant Mortality Rate Per 1 - 000 Live Births 2013 - i) Black Infant Deaths - 2012 - j) Black Infant Deaths - 2013 - k) Black Infant Mortality Rate Per 1 - 000 Live Births 2012 - l) Black Infant Mortality Rate Per 1 - 000 Live Births 2013 - m) Number of Infant Deaths All Races from 2004-2008 - n) Number of Infant Deaths All Races from 2009-2013 - o) Average Infant Mortality Rate of All Races from 2004-2008 - p) Average Infant Mortality Rate of All Races from 2009-2013 - q) Percent Change of Infant Deaths. Values = Rates based on <5 deaths are not presented since rates based on small numbers are statistically unreliable. Feature Service Layer Link: https://mdgeodata.md.gov/imap/rest/services/Health/MD_VitalStatistics/FeatureServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

Each Maryland County's number of infant deaths and infant mortality rates by race in 2012 and 2013. Includes: a) Number of Infant Deaths of All Races, 2012, b) Number of Infant Deaths of All Races, 2013, c) Infant Mortality Rate of All Races Per 1,000 Live Births, 2012, d) Infant Mortality Rate of All Races Per 1,000 Live Births, 2013, e) White Infant Deaths, 2012, f) White Infant Deaths, 2013, g) White Infant Mortality Rate Per 1,000 Live Births 2012, h) White Infant Mortality Rate Per 1,000 Live Births 2013, i) Black Infant Deaths, 2012, j) Black Infant Deaths, 2013, k) Black Infant Mortality Rate Per 1,000 Live Births 2012, l) Black Infant Mortality Rate Per 1,000 Live Births 2013, m) Number of Infant Deaths All Races from 2004-2008, n) Number of Infant Deaths All Races from 2009-2013, o) Average Infant Mortality Rate of All Races from 2004-2008, p) Average Infant Mortality Rate of All Races from 2009-2013, q) Percent Change of Infant Deaths. Values = Rates based on

All cause of death rates by county, Black or African American (Non-Hispanic/Latino), both sexes, all ages, rural and urban, 2019-2023. Death data were provided by the National Vital Statistics System. Death rates (deaths per 100,000 population per year) are age-adjusted to the 2000 US standard population (20 age groups: <1, 1-4, 5-9, ... , 80-84, 85-89, 90+). Rates calculated using SEER*Stat. Population counts for denominators are based on Census populations as modified by the National Cancer Institute. The US Population Data File is used for mortality data.

THIS DATASET WAS LAST UPDATED AT 7:11 AM EASTERN ON DEC. 1

OVERVIEW

2019 had the most mass killings since at least the 1970s, according to the Associated Press/USA TODAY/Northeastern University Mass Killings Database.

In all, there were 45 mass killings, defined as when four or more people are killed excluding the perpetrator. Of those, 33 were mass shootings . This summer was especially violent, with three high-profile public mass shootings occurring in the span of just four weeks, leaving 38 killed and 66 injured.

A total of 229 people died in mass killings in 2019.

The AP's analysis found that more than 50% of the incidents were family annihilations, which is similar to prior years. Although they are far less common, the 9 public mass shootings during the year were the most deadly type of mass murder, resulting in 73 people's deaths, not including the assailants.

One-third of the offenders died at the scene of the killing or soon after, half from suicides.

About this Dataset

The Associated Press/USA TODAY/Northeastern University Mass Killings database tracks all U.S. homicides since 2006 involving four or more people killed (not including the offender) over a short period of time (24 hours) regardless of weapon, location, victim-offender relationship or motive. The database includes information on these and other characteristics concerning the incidents, offenders, and victims.

The AP/USA TODAY/Northeastern database represents the most complete tracking of mass murders by the above definition currently available. Other efforts, such as the Gun Violence Archive or Everytown for Gun Safety may include events that do not meet our criteria, but a review of these sites and others indicates that this database contains every event that matches the definition, including some not tracked by other organizations.

This data will be updated periodically and can be used as an ongoing resource to help cover these events.

Using this Dataset

To get basic counts of incidents of mass killings and mass shootings by year nationwide, use these queries:

Mass killings by year

Mass shootings by year

To get these counts just for your state:

Filter killings by state

Definition of "mass murder"

Mass murder is defined as the intentional killing of four or more victims by any means within a 24-hour period, excluding the deaths of unborn children and the offender(s). The standard of four or more dead was initially set by the FBI.

This definition does not exclude cases based on method (e.g., shootings only), type or motivation (e.g., public only), victim-offender relationship (e.g., strangers only), or number of locations (e.g., one). The time frame of 24 hours was chosen to eliminate conflation with spree killers, who kill multiple victims in quick succession in different locations or incidents, and to satisfy the traditional requirement of occurring in a “single incident.”

Offenders who commit mass murder during a spree (before or after committing additional homicides) are included in the database, and all victims within seven days of the mass murder are included in the victim count. Negligent homicides related to driving under the influence or accidental fires are excluded due to the lack of offender intent. Only incidents occurring within the 50 states and Washington D.C. are considered.

Methodology

Project researchers first identified potential incidents using the Federal Bureau of Investigation’s Supplementary Homicide Reports (SHR). Homicide incidents in the SHR were flagged as potential mass murder cases if four or more victims were reported on the same record, and the type of death was murder or non-negligent manslaughter.

Cases were subsequently verified utilizing media accounts, court documents, academic journal articles, books, and local law enforcement records obtained through Freedom of Information Act (FOIA) requests. Each data point was corroborated by multiple sources, which were compiled into a single document to assess the quality of information.

In case(s) of contradiction among sources, official law enforcement or court records were used, when available, followed by the most recent media or academic source.

Case information was subsequently compared with every other known mass murder database to ensure reliability and validity. Incidents listed in the SHR that could not be independently verified were excluded from the database.

Project researchers also conducted extensive searches for incidents not reported in the SHR during the time period, utilizing internet search engines, Lexis-Nexis, and Newspapers.com. Search terms include: [number] dead, [number] killed, [number] slain, [number] murdered, [number] homicide, mass murder, mass shooting, massacre, rampage, family killing, familicide, and arson murder. Offender, victim, and location names were also directly searched when available.

This project started at USA TODAY in 2012.

Contacts

Contact AP Data Editor Justin Myers with questions, suggestions or comments about this dataset at jmyers@ap.org. The Northeastern University researcher working with AP and USA TODAY is Professor James Alan Fox, who can be reached at j.fox@northeastern.edu or 617-416-4400.