Two scientists in protective gear

Photo credit: Smithsonian Magazine

This week, the World Health Organization released a list of diseases that have the potential to cause public health emergencies, and that have no efficacious drugs or vaccines.  The list was meant to direct and prioritize research and development and included some familiar names: Crimean-Congo hemorrhagic fever, Ebola and Marburg virus diseases, and Lassa fever.  The most interesting disease among the list of eight was the last: “Disease X”.  What is Disease X?

Disease X is not so much a disease as it is a concept.  Disease X represents the unknown, and the likelihood that a new disease can emerge at any time and cause a serious international epidemic if the world does not prepare for such an event.  By creating this mysterious disease, WHO is implicitly encouraging the world to be prepared for the next unforeseen outbreak, something experts generally agree could happen any time, and is an event which has been long overdue.

Perhaps not coincidentally, this new deadly, mysterious pathogen was created this week on March 11, one hundred years to the day that the first cases of “Spanish flu” were reported at Fort Riley, Kansas.  The “Spanish flu”, or H1N1, would go on to cause a pandemic of influenza that would infect a third of the world’s population, and kill between 20-50 million.

A quick internet search of “next pandemic” should be enough to convince anyone that there is a great deal of concern for the health and safety of the world, in the context of disease outbreaks and global health security.  Although many in public health feel that they know what the next pandemic will be, and are working towards preparing us for such an event, the truth is no one really knows what will cause the next pandemic.  The WHO would like for you to consider the unknown, the disease you haven’t prepared for – the mysterious Disease X.