Disease X is a postulated name of the disease which was added by the WHO in a blueprint priority disease list in 2018. This list is prepared by the WHO in which it includes the pathogens which have the epidemic potential and should be prioritised for the Research and Development. Disease X is one among them which can cause the pandemic in the around future. Development of vaccines formation and

distribution and other health-related facilities should be developed by prioritising these possibilities.
Professor Jean-Jacques Muyembe-Tamfum from Colombo who discovered Ebola in 1976 warned recently for the upcoming disease X which can spread as fast as Corona pandemic and have a mortality rate equal to 50 to 90 per cent of Ebola's mortality rate. The report also mentioned about the unusual case from Congo where a woman having haemorrhagic fever tested negative for Ebola and other similar diseases. Doctors feared that she can be the patient zero of the disease X.
Corona pandemic can also be contemplated as disease X since it was unknown to the scientists when it spread worldwide. There are many pathogens which are in the forests or near the cities which can enter the animal kingdom anytime. These are the zoonotic diseases which pass on to human beings through animals. HIV is thought to be passed from Chimpanzee and then mutated. SARAS-CoV-2, SARAS, MERS all belong to the coronaviridae family spread to human beings from the unknown reservoirs to the animal kingdom.
Currently, the following list of disease is in the priority of WHO.
1. COVID-19
2. Crimean-Congo haemorrhagic fever
3. Ebola virus disease and Marburg virus disease
4. Lassa fever
5. Middle East respiratory syndrome coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS)
6. Nipah and henipaviral diseases
7. Rift Valley fever
8. Zika
9. “Disease X”