World Health Organization gets ready for 'Disease X'

By Susan Scutti, CNN

Updated 1627 GMT (0027 HKT) March 12, 2018

There were 216,000 global cases of leprosy, an ancient and disfiguring disease, in 2013.
Photos: 10 diseases you thought were gone
There were 216,000 global cases of leprosy, an ancient and disfiguring disease, in 2013.
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In the 19th century, scarlet fever was a common killer in Europe. In 2016, nearly 20,000 cases were reported in the United Kingdom -- the biggest increase in 50 years.<br /><br />Scarlet fever is just one disease that many have forgotten but that is by no means gone, despite our best efforts to eliminate it.
Photos: 10 diseases you thought were gone
In the 19th century, scarlet fever was a common killer in Europe. In 2016, nearly 20,000 cases were reported in the United Kingdom -- the biggest increase in 50 years.

Scarlet fever is just one disease that many have forgotten but that is by no means gone, despite our best efforts to eliminate it.
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Though it's often thought of as a medieval disease, the World Health Organization reports 1,000 to 3,000 global cases of plague every year. The US averages seven new human cases a year, <a href="https://www.cdc.gov/plague/maps/index.html" target="_blank">mostly in the Southwest</a>. Pictured, a patient with gangrene and necrosis, caused by plague.<br />
Photos: 10 diseases you thought were gone
Though it's often thought of as a medieval disease, the World Health Organization reports 1,000 to 3,000 global cases of plague every year. The US averages seven new human cases a year, mostly in the Southwest. Pictured, a patient with gangrene and necrosis, caused by plague.
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This 19-year-old girl in Neijiang, China, is being carried in a basket because she has rickets. Rickets is caused by a lack of vitamin D, which we get from sunlight. Experts believe rickets is making a comeback in developed countries because of the use of sunscreen and less time spent outdoors.
Photos: 10 diseases you thought were gone
This 19-year-old girl in Neijiang, China, is being carried in a basket because she has rickets. Rickets is caused by a lack of vitamin D, which we get from sunlight. Experts believe rickets is making a comeback in developed countries because of the use of sunscreen and less time spent outdoors.
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Gout was once known as the "disease of kings" because of its links to excessive food and alcohol consumption. These days, unhealthy lifestyles are behind an increase in gout in developed countries.
Photos: 10 diseases you thought were gone
Gout was once known as the "disease of kings" because of its links to excessive food and alcohol consumption. These days, unhealthy lifestyles are behind an increase in gout in developed countries.
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The deadly disease diphtheria affects the nose and throat. Vaccinations mean it is now rare in developed countries, but in 2011, nearly 5,000 cases were reported to the WHO, with many more probably unreported.<br />
Photos: 10 diseases you thought were gone
The deadly disease diphtheria affects the nose and throat. Vaccinations mean it is now rare in developed countries, but in 2011, nearly 5,000 cases were reported to the WHO, with many more probably unreported.
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Although there is a pertussis vaccine, there were an <a href="http://www.who.int/immunization/topics/pertussis/en/" target="_blank">estimated 16 million global cases</a> of whooping cough in 2008, killing about 195,000 children.
Photos: 10 diseases you thought were gone
Although there is a pertussis vaccine, there were an estimated 16 million global cases of whooping cough in 2008, killing about 195,000 children.
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In April 2015, the Americas became the first region to eliminate rubella; the <a href="https://www.cdc.gov/rubella/about/in-the-us.html" target="_blank">Centers for Disease Control and Prevention says</a> there are fewer than 10 cases each year.<strong> </strong>But globally, about <a href="https://measlesrubellainitiative.org/resources/advocacy-tools/2017-fact-sheet/" target="_blank">110,000 babies</a> are born with <a href="http://www.cnn.com/2016/09/08/health/rubella-house-zika-babies-future/index.html">congenital rubella syndrome</a> every year.
Photos: 10 diseases you thought were gone
In April 2015, the Americas became the first region to eliminate rubella; the Centers for Disease Control and Prevention says there are fewer than 10 cases each year. But globally, about 110,000 babies are born with congenital rubella syndrome every year.
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TB, or tuberculosis, is one of the top 10 killers in the world, according to the WHO. In 2016, 10.4 million people around the globe contracted tuberculosis, and more than 1.7 million died. Ninety-five percent of those <a href="http://www.cnn.com/2017/03/24/health/tuberculosis-cambodia-tb-day-photos/index.html">deaths were in developing countries</a>.
Photos: 10 diseases you thought were gone
TB, or tuberculosis, is one of the top 10 killers in the world, according to the WHO. In 2016, 10.4 million people around the globe contracted tuberculosis, and more than 1.7 million died. Ninety-five percent of those deaths were in developing countries.
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