Healthcare

Visualizing the History of Pandemics

Published

21 hours ago

on

March 14, 2020

The History of Pandemics

Pan·dem·ic /panˈdemik/ (of a disease) prevalent over a whole country or the world.

As humans have spread across the world, so have infectious diseases. Even in this modern era, outbreaks are nearly constant, though not every outbreak reaches pandemic level as the Novel Coronavirus (COVID-19) has.

Today’s visualization outlines some of history’s most deadly pandemics, from the Antonine Plague to the current COVID-19 event.

A Timeline of Historical Pandemics

Disease and illnesses have plagued humanity since the earliest days, our mortal flaw. However, it was not until the marked shift to agrarian communities that the scale and spread of these diseases increased dramatically.

Widespread trade created new opportunities for human and animal interactions that sped up such epidemics. Malaria, tuberculosis, leprosy, influenza, smallpox, and others first appeared during these early years.

The more civilized humans became – with larger cities, more exotic trade routes, and increased contact with different populations of people, animals, and ecosystems – the more likely pandemics would occur.

Here are some of the major pandemics that have occurred over time:

NameTime periodType / Pre-human hostDeath toll
Antonine Plague165-180Believed to be either smallpox or measles5M
Japanese smallpox epidemic735-737Variola major virus1M
Plague of Justinian541-542Yersinia pestis bacteria / Rats, fleas30-50M
Black Death1347-1351Yersinia pestis bacteria / Rats, fleas200M
New World Smallpox Outbreak1520 – onwardsVariola major virus56M
Great Plague of London1665Yersinia pestis bacteria / Rats, fleas100,000
Italian plague1629-1631Yersinia pestis bacteria / Rats, fleas1M
Cholera Pandemics 1-61817-1923V. cholerae bacteria1M+
Third Plague1885Yersinia pestis bacteria / Rats, fleas12M (China and India)
Yellow FeverLate 1800sVirus / Mosquitoes100,000-150,000 (U.S.)
Russian Flu1889-1890Believed to be H2N2 (avian origin)1M
Spanish Flu1918-1919H1N1 virus / Pigs40-50M
Asian Flu1957-1958H2N2 virus1.1M
Hong Kong Flu1968-1970H3N2 virus1M
HIV/AIDS1981-presentVirus / Chimpanzees25-35M
Swine Flu2009-2010H1N1 virus / Pigs200,000
SARS2002-2003Coronavirus / Bats, Civets770
Ebola2014-2016Ebolavirus / Wild animals11,000
MERS2015-PresentCoronavirus / Bats, camels850
COVID-192019-PresentCoronavirus – Unknown (possibly pangolins)4,700 (as of Mar 12, 2020)

Note: Many of the death toll numbers listed above are best estimates based on available research. Some, such as the Plague of Justinian, are subject to debate based on new evidence.

Despite the persistence of disease and pandemics throughout history, there’s one consistent trend over time – a gradual reduction in the death rate. Healthcare improvements and understanding the factors that incubate pandemics have been powerful tools in mitigating their impact.

Wrath of the Gods

In many ancient societies, people believed that spirits and gods inflicted disease and destruction upon those that deserved their wrath. This unscientific perception often led to disastrous responses that resulted in the deaths of thousands, if not millions.

In the case of Justinian’s plague, the Byzantine historian Procopius of Caesarea traced the origins of the plague (the Yersinia pestis bacteria) to China and northeast India, via land and sea trade routes to Egypt where it entered the Byzantine Empire through Mediterranean ports.

Despite his apparent knowledge of the role geography and trade played in this spread, Procopius laid blame for the outbreak on the Emperor Justinian, declaring him to be either a devil, or invoking God’s punishment for his evil ways. Some historians found that this event could have dashed Emperor Justinian’s efforts to reunite the Western and Eastern remnants of the Roman Empire, and marked the beginning of the Dark Ages.

Luckily, humanity’s understanding of the causes of disease has improved, and this is resulting in a drastic improvement in the response to modern pandemics, albeit slow and incomplete.

Importing Disease

The practice of quarantine began during the 14th century, in an effort to protect coastal cities from plague epidemics. Cautious port authorities required ships arriving in Venice from infected ports to sit at anchor for 40 days before landing — the origin of the word quarantine from the Italian “quaranta giorni”, or 40 days.

One of the first instances of relying on geography and statistical analysis was in mid-19th century London, during a cholera outbreak. In 1854, Dr. John Snow came to the conclusion that cholera was spreading via tainted water and decided to display neighborhood mortality data directly on a map. This method revealed a cluster of cases around a specific pump from which people were drawing their water from.

While the interactions created through trade and urban life play a pivotal role, it is also the virulent nature of particular diseases that indicate the trajectory of a pandemic.

Tracking Infectiousness

Scientists use a basic measure to track the infectiousness of a disease called the reproduction number — also known as R0 or “R naught.” This number tells us how many susceptible people, on average, each sick person will in turn infect.

Measles tops the list, being the most contagious with a R0 range of 12-18. This means a single person can infect, on average, 12 to 18 people in an unvaccinated population.

While measles may be the most virulent, vaccination efforts and herd immunity can curb its spread. The more people are immune to a disease, the less likely it is to proliferate, making vaccinations critical to prevent the resurgence of known and treatable diseases.

It’s hard to calculate and forecast the true impact of COVID-19, as the outbreak is still ongoing and researchers are still learning about this new form of coronavirus.

Urbanization and the Spread of Disease

We arrive at where we began, with rising global connections and interactions as a driving force behind pandemics. From small hunting and gathering tribes to the metropolis, humanity’s reliance on one another has also sparked opportunities for disease to spread.

Urbanization in the developing world is bringing more and more rural residents into denser neighborhoods, while population increases are putting greater pressure on the environment. At the same time, passenger air traffic nearly doubled in the past decade. These macro trends are having a profound impact on the spread of infectious disease.

As organizations and governments around the world ask for citizens to practice social distancing to help reduce the rate of infection, the digital world is allowing people to maintain connections and commerce like never before.

Editor’s Note: The COVID-19 pandemic is in its early stages and it is obviously impossible to predict its future impact. This post and infographic are meant to provide historical context, and we will continue to update it as time goes on to maintain its accuracy.

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Demographics

The Global Inequality Gap, and How It’s Changed Over 200 Years

This visualization shows the global inequality gap — a difference in the standards of living around the world, as well as how it’s changed over 200 years.

Published

3 months ago

on

December 3, 2019

How the Global Inequality Gap Has Changed In 200 Years

What makes a person healthy, wealthy, and wise? The UN’s Human Development Index (HDI) measures this by one’s life expectancy, average income, and years of education.

However, the value of each metric varies greatly depending on where you live. Today’s data visualization from Max Roser at Our World in Data summarizes five basic dimensions of development across countries—and how our average standards of living have evolved since 1800.

Health: Mortality Rates and Life Expectancy

Child mortality rates and life expectancy at birth are telltale signs of a country’s overall standard of living, as they indicate a population’s ability to access healthcare services.

Iceland stood at the top of these ranks in 2017, with only a 0.21% mortality rate for children under five years old. On the other end of the spectrum, Somalia had the highest child mortality rate of 12.7%—over three times the current global average.

While there’s a stark contrast between the best and worst performing countries, it’s clear that even Somalia has made significant strides since 1800. At that time, the global average child mortality rate was a whopping 43%.

Lower child mortality is also tied to higher life expectancy. In 1800, the average life expectancy was that of today’s millennial—only 29 years old:

Today, the global average has shot up to 72.2 years, with areas like Japan exceeding this benchmark by more than a decade.

Education: Mean and Expected Years of Schooling

Education levels are measured in two distinct ways:

  • Mean years: the average number of years a person aged 25+ receives in their lifetime
  • Expected years: the total years a 2-year old child is likely to spend in school

In the 1800s, the mean and expected years of education were both less than a year—only 78 days to be precise. Low attendance rates occurred because children were expected to work during harvests, or contracted long-term illnesses that kept them at home.

Since then, education levels have drastically improved:

 Mean Years of SchoolingExpected Years of schooling 
Global Average8.4 years12.7 years
HighestGermany : 14.1 yearsAustralia : 22.9 years
LowestBurkina Faso : 1.5 yearsSouth Sudan : 4.9 years

Mean years of schooling, 2017

Average number of years of total schooling across all education levels, for the population aged 25+

Source: Lee-Lee (2016), Barro-Lee (2018) and UNDP, HDR (2018)

Research shows that investing in education can greatly narrow the inequality gap. Just one additional year of school can:

  • Raise a person’s income by up to 10%
  • Raise average annual GDP growth by 0.37%
  • Reduce the probability of motherhood by 7.3%
  • Reduce the likelihood of child marriage by >5 percentage points
  • Source

    Education has a strong correlation with individual wealth, which cascades into national wealth. Not surprisingly, average income has ballooned significantly in two centuries as well.

    Wealth: Average GDP Per Capita

    Global inequality levels are the most stark when it comes to GDP per capita. While the U.S. stands at $54,225 per person in 2017, resource-rich Qatar brings in more than double this amount—an immense $116,936 per person.

    The global average GDP per capita is $15,469, but inequality heavily skews the bottom end of these values. In the Central African Republic, GDP per capita is only $661 today—similar to the average income two hundred years ago.

    GDP per capita

    GDP per capita adjusted for price changes over time (inflation) and price differences between countries – it is
    measured in international-$ in 2011 prices.

    Source: Maddison Project Database (2018)

    Note: These series are adjusted for price differences between countries based on only a single benchmark year, in 2011. This makes them
    suitable for studying the growth of incomes over time but not for comparing income levels between countries.

    1000
    2016
    Relative change

    A Virtuous Cycle

    These measures of development clearly feed into one another. Rising life expectancies are an indication of a society’s growing access to healthcare options. Compounded with more years of education, especially for women, this has had a ripple effect on declining fertility rates, contributing to higher per capita incomes.

    People largely agree on what goes into human well-being: life, health, sustenance, prosperity, peace, freedom, safety, knowledge, leisure, happiness… If they have improved over time, that, I submit, is progress.

    Steven Pinker

    As technology accelerates the pace of change across these indicators, will the global inequality gap narrow more, or expand even wider?

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Healthcare

The Future of Nanotechnology in Medicine

This infographic highlights some of the most promising nanotechnology breakthroughs in medicine, from ‘smart pills’ to targeted cancer treatment.

Published

5 months ago

on

October 15, 2019

The Future of Nanotechnology in Medicine

Around the world, researchers are increasingly thinking smaller to solve some of the biggest problems in medicine.

Though most biological processes happen at the nano level, it wasn’t until recently that new technological advancements helped in opening up the possibility of nanomedicine to healthcare researchers and professionals.

Today’s infographic, which comes to us from Best Health Degrees, highlights some of the most promising research in nanomedicine.

What is Nanotechnology?

Nanotechnology is the engineering of functional systems at the molecular level. The field combines elements of physics and molecular chemistry with engineering to take advantage of unique properties that occur at nanoscale.

One practical example of this technology is the use of tiny carbon nanotubes to transport drugs to specific cells. Not only do these nanotubes have low toxicity and a stable structure, they’re an ideal container for transporting drugs directly to the desired cells.

Small Systems, Big Applications

While many people will be most familiar with nanotech as the technology powering Iron Man’s suit, real world breakthroughs at the nanoscale will soon be saving lives in healthcare.

Here are a few ways nanotechnology is shaping the future of medical treatment:

1. Smart Pills

While smart pill technology is not a new idea — a “pill cam” was cleared by the FDA in 2001 — researchers are coming up with innovative new applications for the concept.

For example, MIT researchers designed an ingestible sensor pill that can be wirelessly controlled. The pill would be a “closed-loop monitoring and treatment” solution, adjusting the dosage of a particular drug based on data gathered within the body (e.g. gastrointestinal system).

An example of this technology in action is the recent FDA-approved smart pill that records when medication was taken. The product, which is approved for people living with schizophrenia and bipolar disorder, allows patients to track their own medication history through a smartphone, or to authorize physicians and caregivers to access that information online.

2. Beating the Big C

Nearly 40% of humans will be diagnosed with cancer at some point in their lifetime, so any breakthrough in cancer treatment will have a widespread impact on society.

On the key issues with conventional chemotherapy and radiation treatments is that the body’s healthy cells can become collateral damage during the process. For this reason, researchers around the world are working on using nano particles to specifically target cancer cells.

Oncology-related drugs have the highest forecasted worldwide prescription drug sales, and targeting will be a key element in the effectiveness of these powerful new drugs.

3. Diagnostics

Medical implants — such as knee and hip replacements — have improved the lives of millions, but a common problem with these implants is the risk of post-surgery inflammation and infection. In many cases, symptoms from an infection are detected so late that treatment is less effective, or the implant will need to be replaced all together.

Nanoscale sensors embedded directly into the implant or surrounding area could detect infection much sooner. As targeted drug delivery becomes more feasible, it could be possible to administer treatment to an infected area at the first sign of infection.

Examples like this show the true promise of nanotechnology in the field of medicine. Before long, gathering data from within the body and administering treatments in real-time could move from science fiction to the real world.

10,000 years ago, man domesticated plants and animals, now it’s time to domesticate molecules.

– Professor Susan Lindquist

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