WHO created this list to record the pathogens which are likely to affect and kill a large population globally in the near future, with the first list being released in December 2015, which all pose major risks needing urgent further research, diagnostics and surveillance. WHO states that diseases such as Zika, SARS, Ebola, and Lassa fever have all caused outbreaks in the past few years, each outbreak was very difficult to combat. This new disease called Disease X has been added to the list as a serious threat on the new February warning the public of these major worldwide threats.
WHO claims the next outbreak is going to be something never seen by scientists before. Disease X represents knowledge that a possible international epidemic serious in nature could be cause by a currently unknown pathogen. WHO states development and research is underway to prepare for Disease X as far as possible. The most likely cause of spread is presumed to be animal borne or zoonotic, spread from animals to humans in a similar manners as salmonella, Ebola, and HIV. Jumps from animal to human happen as ecosystems clash and animals lose habitats. It is estimated that close to 70% of recently known diseases which affect humans are known to be zoonoses.
Several diseases have been dropped from priority listing this year according to WHO including non-polio enteroviruses and hemorrhagic fevers, but they may be relisted. Diseases on the priority listing with urgent need for accelerated research include Ebola, Lassa fever, Marburg virus disease, Crimean-Congo haemorrhagic fever, SARS, MERS-CoV, Rift Valley fever, Zika, Nipah and henipaviral disease, and Disease X. Possible new inclusion may Severe Fever with Thrombocytopenia Syndrome, Leptospirosis, Monkeypox, Chikungunya, arenaviral hemorrhagic fever other than Lassa Fever, highly pathogenic coronaviral diseases other than SARS and MERS, and emergent non-polio enteroviruses.
