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.

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.

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) ...

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.

BackgroundPlague is an epidemic-prone disease with a potential impact on public health, international trade, and tourism. It may emerge and re-emerge after decades of epidemiological silence. Today, in Latin America, human cases and foci are present in Bolivia, Brazil, Ecuador, and Peru.AimsThe objective of this study is to identify where cases of human plague still persist in Latin America and map areas that may be at risk for emergence or re-emergence. This analysis will provide evidence-based information for countries to prioritize areas for intervention.MethodsEvidence of the presence of plague was demonstrated using existing official information from WHO, PAHO, and Ministries of Health. A geo-referenced database was created to map the historical presence of plague by country between the first registered case in 1899 and 2012. Areas where plague still persists were mapped at the second level of the political/administrative divisions (counties). Selected demographic, socioeconomic, and environmental variables were described.ResultsPlague was found to be present for one or more years in 14 out of 25 countries in Latin America (1899–2012). Foci persisted in six countries, two of which have no report of current cases. There is evidence that human cases of plague still persist in 18 counties. Demographic and poverty patterns were observed in 11/18 counties. Four types of biomes are most commonly found. 12/18 have an average altitude higher than 1,300 meters above sea level.DiscussionEven though human plague cases are very localized, the risk is present, and unexpected outbreaks could occur. Countries need to make the final push to eliminate plague as a public health problem for the Americas. A further disaggregated risk evaluation is recommended, including identification of foci and possible interactions among areas where plague could emerge or re-emerge. A closer geographical approach and environmental characterization are suggested.

The Hong Kong plague epidemic, which began in 1894, gave way to some of the most important discoveries in the field of epidemiology. Swiss-French scientist, Andre Yersin, successfully identified the plague-causing bacteria Yersinia pestis, and showed that this bacteria was also present in rodents during this time. Following this discovery, scientists then investigated the connection further, in order to establish the extent of the infection in rats. Results In these experiments, all of the rats tested carried the plague in their blood, and over 90 percent had it in their spleen. The four tests conducted had similar results in both regions, although the infections had typically spread further within the rats by June than it had in May. The significance of these infections was that each rat became more contagious as the disease spread to other parts of the body. For example, as all of these rats had contaminated blood, this meant that any fleas or other animals who fed on infected rats would likely contract the disease as a result; in contrast, only 15 to 34 percent of those studied had plague bacteria in their saliva, meaning that a bite from an infected rat would generally not transmit the plague. Plague today While human diseases such as smallpox and polio have been or are in the process of being eradicated through vaccination, the presence of plague in rat colonies makes it much more difficult to eradicate. While increased sanitation and control measures have made plague almost non-existent in most countries, it continues to be endemic to rural areas of sub-Saharan Africa, Madagascar, and Peru. Between 2010 and 2015, there were 3,248 cases and 584 deaths worldwide due to plague, mostly in the aforementioned areas. The reason for its continued existence is due difficulties in locating and exterminating the infected rat colonies which act as natural reservoirs for the disease. Nonetheless, while the number of cases and deaths has been very low for decades, these numbers continue to decrease and this trend is expected to continue into the future.

The New York Times is releasing a series of data files with cumulative counts of coronavirus cases in the United States, at the state and county level, over time. We are compiling this time series data from state and local governments and health departments in an attempt to provide a complete record of the ongoing outbreak.

Since late January, The Times has tracked cases of coronavirus in real time as they were identified after testing. Because of the widespread shortage of testing, however, the data is necessarily limited in the picture it presents of the outbreak.

We have used this data to power our maps and reporting tracking the outbreak, and it is now being made available to the public in response to requests from researchers, scientists and government officials who would like access to the data to better understand the outbreak.

The data begins with the first reported coronavirus case in Washington State on Jan. 21, 2020. We will publish regular updates to the data in this repository.

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.

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.

Plague (caused by the bacterium Yersinia pestis) is a deadly flea-borne disease that remains a threat to public health nearly worldwide and is particularly disruptive ecologically where it has been introduced. We review hypotheses regarding maintenance and transmission of Y. pestis, emphasizing recent data from North America supporting maintenance by persistent transmission that results in sustained non-epizootic (but variable) rates of mortality in hosts. This maintenance mechanism may facilitate periodic epizootic eruptions “in place” because the need for repeated reinvasion from disjunct sources is eliminated. Resulting explosive outbreaks that spread rapidly in time and space are likely enhanced by synergistic positive feedback (PFB) cycles involving flea vectors, hosts, and the plague bacterium itself. Although PFB has been implied in plague literature for at least 50 years, we propose this mechanism, particularly with regard to flea responses, as central to epizootic plague rather than a phenomenon worthy of just peripheral mention. We also present new data on increases in flea:host ratios resulting from recreational shooting and poisoning as possible triggers for the transition from enzootic maintenance to PFB cycles and epizootic explosions. Although plague outbreaks have received much historic attention, PFB cycles that result in decimation of host populations lead to speculation that epizootic eruptions might not be part of the adaptive evolutionary strategy of Y. pestis but might instead be a tolerated intermittent cost of its modus operandi. We also speculate that there may be mammal communities where epizootics, as we define them, are rare or absent. Absence of plague epizootics might translate into reduced public health risk but does not necessarily equate to inconsequential ecologic impact.

Plague, caused by Yersinia pestis, was classified as a reemerging infectious disease by the World Health Organization. The five human pneumonic plague cases in Yulong County in 2005 gave rise to the discovery of a Yulong plague focus in Yunnan province, China. Thereafter, continuous wild rodent plague (sylvatic plague) was identified as the main plague reservoir of this focus. In this study, the epizootics in Yulong focus were described, and three molecular typing methods, including the different region (DFR) analysis, clustered regularly interspaced short palindromic repeats (CRISPRs), and the multiple-locus variable number of tandem repeats (VNTR) analysis (MLVA) (14+12), were used for the molecular typing and source tracing of Y. pestis isolates in the Yulong plague focus. Simultaneously, several isolates from the vicinity of Yunnan were used as controls. The results showed that during the 10-year period from 2006 to 2016, an animal plague epidemic occurred in 6 of those years, and 5 villages underwent an animal plague epidemic within a 30-km2 area of the Yulong plague focus. Searching for dead mice was the most effective monitoring method in this plague focus. No positive sample has been found in 6937 captured live rodents thus far, suggesting that the virulence of strains in the Yulong plague focus is stronger and the survival time of mice is shorter after infection. Strains from Lijiang, Sichuan and Tibet were of the same complex based on a typing analysis of DFR and CRISPR. The genetic relationship of Y. pestis illustrated by MLVA “14+12” demonstrates that Tibet and Sichuan strains evolved from the strains 1.IN2 (Qinghai, 1970 and Tibet, 1976), and Lijiang strains are closer to Batang strains (Batang County in Sichuan province, 2011, Himalaya marmot plague foci) in terms of genetic or phylogenic relationships. In conclusion, we have a deeper understanding of this new plague focus throughout this study, which provides a basis for effective prevention and control.

Distribution of genetic diversity of Y. pestis in Madagascar.

Summary of the different advantages and drawbacks of the techniques used to genotype Y. pestis in Madagascar.

In 2021, there were around ****** confirmed cases of Lyme disease, making it the most common vector-borne disease in the United States. Lyme disease is transmitted to humans through ticks. The most common mosquito-borne disease in the U.S. at that time was West Nile virus. This statistic displays the number of cases of notifiable vector-borne diseases in the U.S. in 2021, by disease. Vector-borne disease Vector-borne diseases are infectious human illnesses caused by parasites, viruses, or bacteria, and are transmitted through other living organisms called vectors, either between humans or from animal to human. Common vectors include mosquitoes, ticks, and various types of flies. Mosquitoes cause the highest number of human deaths annually worldwide, as they transmit diseases such as malaria, West Nile virus, and Dengue. Lyme disease In the United States, the highest number of confirmed cases of Lyme disease in 2022 was reported in New York. After a bite from an infected tick, if left untreated, the infection can spread through different body systems, causing a variety of potentially debilitating and chronic symptoms. When signs of the disease, such as EM rash, fever, and fatigue are recognized early on, antibiotics can combat the spread of the infection to complete recovery.

Environmental compliance monitoring associated with the Port Miami dredging project (2013–2015), designed to assess the impact of project-generated sediments on the local coral community, fortuitously captured a thermal bleaching event and the first reports of an emergent, highly contagious, white-plague-like coral disease outbreak in the fall of 2014. The disease, now termed stony coral tissue loss disease (SCTLD), has decimated reefs throughout Florida and is now spreading across the Caribbean. The high prevalence of disease, the number of affected species, and the high mortality of corals affected suggests SCTLD may be the most lethal coral disease ever recorded. Previous analyses of the dredge monitoring data have reached mixed conclusions about the relative impact of dredging on coral mortality and has often parsed out disease susceptible individuals to isolate the impacts of dredging only. We use multi-variate analyses, including time-based survival analyses, to examine the timing and impacts of dredging, coral bleaching, and disease on local coral mortality. By examining the status of corals monthly from the October 2013 to July 2015 observational period, we found that coral mortality was not significantly affected by a coral’s proximity to the dredge site or sediment burial. Instead, coral mortality was most strongly impacted by disease and the emergence of SCTLD during the monitoring period. During the 2-year monitoring period, 26.3% of the monitored corals died, but the only conditions significantly affected by the dredge were partial burial and partial mortality. The strongest link to mortality was due to disease, which impacted coral species differently depending on their susceptibility to SCTLD. The focus on disturbances associated with dredging created a circumstance where the greater impacts of this emergent disease were downplayed, leading to a false narrative of the resulting mortality on the local coral communities. The results of this study reveal that while local events such as a dredging project do have quantifiable effects and can be harmful to corals, regional and global threats that result in mass coral mortality such as thermal stress and disease represent an existential threat to coral reefs and must be urgently addressed.

For most of the world, throughout most of human history, the average life expectancy from birth was around 24. This figure fluctuated greatly depending on the time or region, and was higher than 24 in most individual years, but factors such as pandemics, famines, and conflicts caused regular spikes in mortality and reduced life expectancy. Child mortality The most significant difference between historical mortality rates and modern figures is that child and infant mortality was so high in pre-industrial times; before the introduction of vaccination, water treatment, and other medical knowledge or technologies, women would have around seven children throughout their lifetime, but around half of these would not make it to adulthood. Accurate, historical figures for infant mortality are difficult to ascertain, as it was so prevalent, it took place in the home, and was rarely recorded in censuses; however, figures from this source suggest that the rate was around 300 deaths per 1,000 live births in some years, meaning that almost one in three infants did not make it to their first birthday in certain periods. For those who survived to adolescence, they could expect to live into their forties or fifties on average. Modern figures It was not until the eradication of plague and improvements in housing and infrastructure in recent centuries where life expectancy began to rise in some parts of Europe, before industrialization and medical advances led to the onset of the demographic transition across the world. Today, global life expectancy from birth is roughly three times higher than in pre-industrial times, at almost 73 years. It is higher still in more demographically and economically developed countries; life expectancy is over 82 years in the three European countries shown, and over 84 in Japan. For the least developed countries, mostly found in Sub-Saharan Africa, life expectancy from birth can be as low as 53 years.

The region of present-day China has historically been the most populous region in the world; however, its population development has fluctuated throughout history. In 2022, China was overtaken as the most populous country in the world, and current projections suggest its population is heading for a rapid decline in the coming decades. Transitions of power lead to mortality The source suggests that conflict, and the diseases brought with it, were the major obstacles to population growth throughout most of the Common Era, particularly during transitions of power between various dynasties and rulers. It estimates that the total population fell by approximately 30 million people during the 14th century due to the impact of Mongol invasions, which inflicted heavy losses on the northern population through conflict, enslavement, food instability, and the introduction of bubonic plague. Between 1850 and 1870, the total population fell once more, by more than 50 million people, through further conflict, famine and disease; the most notable of these was the Taiping Rebellion, although the Miao an Panthay Rebellions, and the Dungan Revolt, also had large death tolls. The third plague pandemic also originated in Yunnan in 1855, which killed approximately two million people in China. 20th and 21st centuries There were additional conflicts at the turn of the 20th century, which had significant geopolitical consequences for China, but did not result in the same high levels of mortality seen previously. It was not until the overlapping Chinese Civil War (1927-1949) and Second World War (1937-1945) where the death tolls reached approximately 10 and 20 million respectively. Additionally, as China attempted to industrialize during the Great Leap Forward (1958-1962), economic and agricultural mismanagement resulted in the deaths of tens of millions (possibly as many as 55 million) in less than four years, during the Great Chinese Famine. This mortality is not observable on the given dataset, due to the rapidity of China's demographic transition over the entire period; this saw improvements in healthcare, sanitation, and infrastructure result in sweeping changes across the population. The early 2020s marked some significant milestones in China's demographics, where it was overtaken by India as the world's most populous country, and its population also went into decline. Current projections suggest that China is heading for a "demographic disaster", as its rapidly aging population is placing significant burdens on China's economy, government, and society. In stark contrast to the restrictive "one-child policy" of the past, the government has introduced a series of pro-fertility incentives for couples to have larger families, although the impact of these policies are yet to materialize. If these current projections come true, then China's population may be around half its current size by the end of the century.

It is only in the past two centuries where demographics and the development of human populations has emerged as a subject in its own right, as industrialization and improvements in medicine gave way to exponential growth of the world's population. There are very few known demographic studies conducted before the 1800s, which means that modern scholars have had to use a variety of documents from centuries gone by, along with archeological and anthropological studies, to try and gain a better understanding of the world's demographic development. Genealogical records One such method is the study of genealogical records from the past; luckily, there are many genealogies relating to European families that date back as far as medieval times. Unfortunately, however, all of these studies relate to families in the upper and elite classes; this is not entirely representative of the overall population as these families had a much higher standard of living and were less susceptible to famine or malnutrition than the average person (although elites were more likely to die during times of war). Nonetheless, there is much to be learned from this data. Impact of the Black Death In the centuries between 1200 and 1745, English male aristocrats who made it to their 21st birthday were generally expected to live to an age between 62 and 72 years old. The only century where life expectancy among this group was much lower was in the 1300s, where the Black Death caused life expectancy among adult English noblemen to drop to just 45 years. Experts assume that the pre-plague population of England was somewhere between four and seven million people in the thirteenth century, and just two million in the fourteenth century, meaning that Britain lost at least half of its population due to the plague. Although the plague only peaked in England for approximately eighteen months, between 1348 and 1350, it devastated the entire population, and further outbreaks in the following decades caused life expectancy in the decade to drop further. The bubonic plague did return to England sporadically until the mid-seventeenth century, although life expectancy among English male aristocrats rose again in the centuries following the worst outbreak, and even peaked at more than 71 years in the first half of the sixteenth century.