The organization also considered adding a number of other diseases to its list of global threats, including arenaviral hemorrhagic fevers, Chikungunya, a viral disease transmitted to humans by infected mosquitoes, and highly pathogenic coronaviral diseases.
Disease X was listed by the World Health Organization as one of eight priority diseases.
How is Disease X expected to appear?
"Disease X represents the knowledge that a serious global epidemic could be caused by a pathogen now unknown to cause human disease".
As well as the priority list, WHO listed dengue, yellow fever and HIV/AIDS, as being outside the current scope of the list while still continuing to pose major public health issues. The New York Post suggests that the disease could be used as a weapon or a tool for countries and terrorist organisations that develop biological weapons. This disease could also be hatched by big events like a terrorist act, or smaller incidences like vehicle accidents.
The most recent review took place in February, with experts agreeing the following diseases are the ones that most urgently require researchers' attention: Crimean-Congo haemorrhagic 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 virus. Furthermore, there is need for drugs and vaccines to improve dramatically, while additional research will help the fight against the diseases. Disease X is such potential outbreak of new epidemic threat according to the World Health Organization.
World Health Organization said existing drugs and vaccines need further improvement for several of the diseases considered but not included in the priority list.
"These diseases pose major public health risks and further research and development is needed, including surveillance and diagnostics", WHO said. "Efforts in the interim to understand and mitigate them are encouraged". How do you protect yourself against getting ill?