However, this year a ninth mystery pathogen has been added to the watch list for the first time.
"Disease X represents the knowledge that a serious global epidemic could be caused by a pathogen now unknown to cause human disease, and so the R&D Blueprint explicitly seeks to enable cross-cutting R&D preparedness that is also relevant for an unknown "Disease X" as far as possible", saidWorld Health Organization in a statement.
Experts in WorldHealth Organization has identified "Disease X" as a global threat capable of killing millions in times of an outbreak. And the creation past year in Canada of horsepox - a close relative of the deadly smallpox virus - has heightened fears that Disease X could come out of a renegade laboratory.
"It may seem odd to be adding an "X" but the point is to make sure we prepare and plan flexibly in terms of vaccines and diagnostic tests".
"Disease X speaks to the information that a genuine global scourge could be caused by a pathogen at present obscure to cause human disease", World Health Organization said on its website.
"There is a need to assess the value, where possible, of developing countermeasures for multiple diseases or for families of pathogens", it said.
The World Health Organisation has issued a warning for ‘Disease X
Disease X could spring up from a lot of different sources and infect us via innumerable vectors, Mr. Rottingen says, although zoonotic transmission (an animal virus evolving to infect humans) is the most likely. Ebola is also a zoonosis.
In modern times, humans have spread across the face of the planet, inhabiting and shaping virtually all ecosystems. Chemical weapons had already been used in Syria and both the ISIS and al-Qaeda had in the past claimed to have used chemical in some of its terrorist attacks. "It is vital that we are aware and prepare".
"It is probably the greatest risk".
The New York Post had also highlighted that the development of biological weapons is easier at present because of gene editing and highly advanced computers.
The WHO also hopes it will drive governments across the globe to invest in strengthening local health systems.
Code-named "Disease X", this mystery pathogen hasn't even been discovered yet, but the looming threat of its nearly certain inevitability has secured it a place on the WHO's "most dangerous" list: a catalogue of potential future epidemics for which countermeasures are insufficient - or don't exist at all. These classes will be considered for inclusion on next year's list.
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Programming details are not known, but the app promises live streaming of "full episodes of your favourite shows". A network was initially said to be launching on Spectrum, but the cable company denied such plans.