The Black Death, which hit Europe in 1347, claimed an astonishing 200 million lives in just four years.

But, fortunately, we’re in the clear. Unlike COVID-19, we have clear treatments for the bubonic plague. Additionally, the disease is rare with a few cases every year found in the United States. This means there’s pretty much no chance we’d ever see a pandemic play out like the one in the 14th century.

How did it end? The most popular theory of how the plague ended is through the implementation of quarantines. The uninfected would typically remain in their homes and only leave when it was necessary, while those who could afford to do so would leave the more densely populated areas and live in greater isolation.

There are 3 main forms of plague. Bubonic plague is the most common and is caused by the bite of an infected flea. The plague bacillus, Y. pestis, enters at the bite and travels to the nearest lymph node to replicate.

Bubonic plague is fatal in about 50-70% of untreated cases, but perhaps 10-15% when treated. Septicaemic plague is almost 100% fatal, and perhaps 40% with treatment. Pneumonic plague is 100% fatal, regardless of treatment.

1346 – 1352

Major epidemics and pandemics by death toll

The Spanish flu, also known as the 1918 influenza pandemic, was an unusually deadly influenza pandemic caused by the H1N1 influenza A virus. Lasting from February 1918 to April 1920, it infected 500 million people – about a third of the world’s population at the time – in four successive waves.

Here are four of the worst pandemics from 1720 to 2020: The Great Plague of Marseille (1720-1723): The disease started spreading in Marseille, France in 1720, killing a total of 1,00,000 people.

Plague repeatedly struck the cities of North Africa. Algiers lost 30,000–50,000 to it in 1620–21, and again in 1654–57, 1665, 1691, and 1740–42. Plague remained a major event in Ottoman society until the second quarter of the 19th century.

1420-1423 Norfolk, ‘but the Rolls of Parliament bear undoubted witness to a very severe prevalence of plague in the North about the same time’ [1:221]; 1420 and 1423 [2:36]; 1423 [3:131]. 1467 ‘In 1467 another epidemic swept through parts of England, and was possibly national in scope.

Medical historians tell us there have been nine influenza pandemics in the past 300 years. So one every 30 to 35 years or so, or roughly three per century, is everybody’s best guess about the future frequency of influenza pandemics.

The Western African Ebola virus epidemic (2013–2016) was the most widespread outbreak of Ebola virus disease (EVD) in history, causing major loss of life and socioeconomic disruption in the region, mainly in Guinea, Liberia and Sierra Leone.

The influenza pandemic of 1918–19, also called the Spanish flu, lasted between one and two years. The pandemic occurred in three waves, though not simultaneously around the globe. In the Northern Hemisphere, the first wave originated in the spring of 1918, during World War I.

In October 1918, an estimated 200,000 Americans died from pneumonia and influenza. This worst month of the epidemic recorded an average of more than 6,000 influenza and pneumonia deaths each day across the United States.

Descendants of the 1918 H1N1 virus make up the influenza viruses we’re fighting today. “The 1918 flu is still with us, in that sense,” said Ann Reid, the executive director of the National Center for Science Education who successfully sequenced the genetic makeup of the 1918 influenza virus in the 1990s.

The number of deaths was estimated to be at least 50 million worldwide with about 675,000 occurring in the United States.

The deadliest disease in the world is coronary artery disease (CAD). Also called ischemic heart disease, CAD occurs when the blood vessels that supply blood to the heart become narrowed. Untreated CAD can lead to chest pain, heart failure, and arrhythmias.

Ebola Vaccine This is the first FDA-approved vaccine for Ebola. This vaccine is given as a single dose vaccine and has been found to be safe and protective against Zaire ebolavirus, which has caused the largest and most deadly Ebola outbreaks to date.

On May 3, 2021, the DRC Ministry of Health and WHO declared the end of the Ebola outbreak in North Kivu Province. Visit the Ebola Outbreak section for information on past Ebola outbreaks.