World Health Organization gets ready for 'Disease X'

By Susan Scutti, CNN

Updated 1627 GMT (0027 HKT) March 12, 2018

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Photos: 10 diseases you thought were gone

Medecins Sans Frontieres (Doctors without Borders) workers in Monrovia, Liberia during the Ebola crisis in 2014. The outbreak raised questions about our ability to handle the spread of deadly diseases. Eradicating diseases entirely is a tougher task.

Scroll through to discover more about ten diseases you thought were gone.

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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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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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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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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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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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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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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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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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Vaccination programs mean polio is on the verge of extinction -- but there are still cases in Afghanistan and Pakistan.

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child receives vaccination whooping cough

Story highlights

Ebola, SARS and Zika also made the WHO 2018 list
WHO's plan is intended to accelerate R&D during international health emergencies

(CNN)The World Health Organization included "Disease X" in its most recent global plan for accelerating research and development during health emergencies like the Ebola, SARS or Zika epidemics.

The strategy and preparedness plan, known as the 2018 R&D Blueprint, was published last month. So what, exactly, is Disease X?

This enigmatic name "represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease," according to the WHO.

"As experience has taught us more often than not the thing that is gonna hit us is something that we did not anticipate," said Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases. "Just the way we didn't anticipate Zika, we didn't think there would be an Ebola that would hit cities."

"X" stands for unexpected, he said.

When confronted with the unknown, the WHO recognizes that it must "nimbly move" and that this involves creating platform technologies, explained Fauci.

Essentially, scientists develop customizable recipes for creating vaccines. Then, when an outbreak happens, they can sequence the unique genetics of the virus causing the disease and plug the correct sequence into the already-developed platform to create a new vaccine.

At least 78 dead in Lassa fever outbreak in Nigeria

Fauci said that to develop these platforms scientists must first study entire classes of viruses, such as the flaviviruses, which include Japanese encephalitis, Yellow fever, Zika, and West Nile virus. "If you develop an understanding of the commonalities of those, you can respond more rapidly," he said.

Along with disease X, the WHO named seven other potential global disease threats, each lacking an effective drug or vaccine.

They are: Crimean-Congo hemorrhagic fever (CCHF); Ebola virus disease and Marburg virus disease; Lassa fever; Middle East respiratory syndrome coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS); Nipah and henipaviral diseases Rift Valley fever (RVF); and Zika.

Deadly Marburg virus outbreak declared in Uganda

The R&D Blueprint was born as a result of the Ebola emergency in West Africa which began in March 2014, explained Marie-Paule Kieny, former assistant director-general of Health Systems and Innovation at WHO, in a statement.

Kieny, who led the WHO research and development effort during the Ebola outbreak, said this international emergency taught scientists that research and development needs to be an "integral part" of the response to epidemics.

The 2014-2016 outbreak, the largest since the virus was first discovered in 1976, included a total of 28,616 confirmed, probable and suspected cases and 11,310 deaths in Guinea, Liberia and Sierra Leone, according to WHO.

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WHO's work alongside governments, scientists and private entities "resulted in the first ever fully effective vaccine against Ebola, developed and tested in 12 months as opposed to the 5-10 years such a process would normally take," said Kieny, who welcomed the opportunity to use her Ebola experience to prepare for future health emergencies.