# Empirical View
Encyclopedia entries on some of the most destructive diseases known to mankind are now written in past tense because they’ve been eradicated and are no longer a threat. The status of many diseases are as follows:1
Diseases that have been eradicated: smallpox and rinderpest
Diseases for which eradication is underway: poliomyelitis (polio) and dracunculiasis (guinea worm)
Regionally eliminated or under way: hookworm, malaria, lymphatic filariasis, measles, rubella, onchocerciasis, yaws, bovine spongiform encephalopathy (BSE)
It is hard to estimate the number of smallpox2 victims in the past. Hays (2005)3 writes: “No reliable estimate of the disease’s complete eighteenth-century toll exists, but the deaths certainly numbered in the millions. According to one estimate smallpox was claiming 400,000 European lives a year by the end of the 18th century – at a time when the population of the continent numbered less than 200 million.”
In the last decade of the 18th century, life expectancy was 32 in France and 40.5 in Denmark (see the data by Floud, Fogel, Harris, and Hong (2011) and the Our World in Data entry on life expectancy). Assuming an average life expectancy of 35 means that of the 200 million people 5.7 million died per year. This means that smallpox was the cause of death of 7% of Europeans at that time.
But the history of smallpox is obviously much longer – Pharaoh Ramses V. might be the oldest known victim.4
Today smallpox is a disease of the past. “The last known natural case was in Somalia in 1977. Since then, the only known cases were caused by a laboratory accident in 1978 in Birmingham, England, which killed one person and caused a limited outbreak. Smallpox was officially declared eradicated in 1979.”5
# Deaths from smallpox per 1000 deaths from all causes in London, 1629 to 1900 – Fenner, Henderson, Arita, Jezek, and Ladnyi (1988)6
Below we can see how the introduction of the smallpox vaccine had a profound effect on the smallpox death rate.
Smallpox deaths per million population in Sweden between 1722 and 1843, showing from 1820 onwards the proportion of newborn children who were vaccinated in infancy – Fenner, Henderson, Arita, Jezek, and Ladnyi (1988)7
The following map shows when smallpox was eradicated from each country. Parts of Africa, Southeast Asia, the Middle East and Brazil were the last places to have smallpox eradicated. But smallpox was eradicated from other parts of the world, especially Europe, far earlier, which suggests that slow eradication in some parts of the world was due primarily to weaker control systems and ineffective vaccination strategies.
Rinderpest9, also known as cattle plague, is the first animal disease that was ever eradicated. It was a disease primarily of cattle and buffalo that resulted in fever, oral erosions, diarrhea, other awful symptoms, and eventually death. Death rates during rinderpest outbreaks were remarkably high.
The FAO’s Global Rinderpest Eradication Programme (GREP) worked for decades to eliminate the disease, which was declared eradicated in 201110.
# Video of a world map showing outbreaks of rinderpest between the year 376 and the eradication in 2011 – World Organisation for Animal Health (OIE)11
Poliomyelitis – also called polio or infantile paralysis – has been eliminated from many parts of the world and will hopefully be eradicated globally in the near future. Polio sometimes causes muscle weakness, most commonly in the legs, that can last over a few hours or days. Many people are able to fully recover, but not all. Some cases of polio result in temporary or permanent paralysis or other disability. Years later recovery, people may have post-polio syndrome where they see a resurgence of the muscle weakness during the initial infection. Polio is spread via infected feces12. The reduction in polio cases was made possible by polio vaccines developed in the 1950s. The following map shows the dramatic progress made in eliminating polio because of these vaccines.
# World maps showing the progress in eradicating polio, 1988, 2002 & 2012 – WHO/Global Polio Eradication Initiative13
As the following chart shows, polio is very near eradication. A life ticker on Polio cases worldwide can be found here on polioeradication.org. Polio only persists in a handful of countries in Africa, the Middle East and Eastern Europe. India was declared polio free in 2014 – here is a BBC report on this story.
The following chart shows the growing focus on polio by the scientific community through the 20th century.
# Numbers of publications about polio by year, 1890 to 1986 – Cambridge World History of Human Diseases15
Fascinating is the story of the Australian nurse Robin Miller who, at the age of 26, borrowed money to buy a plane and flew to the outback to eradicate polio. She died due to cancer at the young age of 35.
# Guinea Worm Disease
Guinea worm disease is caused by the largest tissue parasite affecting humans, called the guinea worm. The adult female can be 600-800mm in length. The parasite navigates through the host’s tissue causing severe pain and eventually emerges, usually from the feet. The disease is rarely fatal, but infected people can be sick for months. It is transmitted via contaminated water.16 Fortunately, as we can see from the following chart, the number of guinea worm cases worldwide has decreased dramatically from the late 80s.
The Carter Center – www.cartercenter.org – publishes up to date statistics and the data shown in the following table and chart are obtained from them.
|Cases||~ 3.5 million||22|
|Internationally exported cases||154||0|
From the following map you can see the progress eliminating maternal and neonatal tetanus.
On Our World in Data I have a data entry dedicated to malaria.
Two visualizations that show how Malaria is being reduced around the world are reproduced here. The world map shows that Malaria used to prevalent in much larger parts of the world and has been successfully eradicated in many parts of the world.
# World map of past and current malaria prevalence – World Development Report (2009)18
# Deaths Due to Malaria
The WHO publishes global estimates of the number of people that die from malaria since 2000. Over the 15 year period the number of malaria deaths has been steadily decreasing globally: From 839,000 deaths in 2000 to 438,000 in 2015. Africa is the world region with the most deaths caused by malaria: 9 out of 10 malaria victims are from Africa in 2015. And change in Africa is also responsible for the majority of the decrease over the 15-year period. In 2000 764,000 Africans were killed by Malaria. Until 2015 the number of deaths declined to 395,000 per year.
# Data Quality & Definition
There is often confusion about what “eradication” means. Eradication is the “permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts.” Eradication means that intervention measures are no longer required. “Elimination” refers to the “reduction to zero of the incidence of infection caused by a specific agent in a defined geographic area as a result of deliberate efforts.” A disease can be eliminated from a specific place without being eradicated. Actions to prevent the disease from transmitting or reemerging are still required once a disease is eliminated. 19
# Data Sources
For data on Malaria see the data entry dedicated to Malaria here.
# World Health Organization
- Data: Deaths, cases, and prevention data for some many diseases
- Geographical coverage: WHO member nations
- Time span: Usually about 2000-2013
- Available at: The WHO publishes data here.
# The Global Polio Eradication Initiative
- Data: Polio cases and immunization coverage by country
- Geographical coverage: Countries with polio cases or vulnerable to new polio cases
- Time span: Up to date information of current and recent cases
- Available at: Online here.