The World Health Organization released their Blueprint list of priority diseases this month, and while it included some recognizable names like Ebola and Zika, it also included an unfamiliar candidate called Disease X.
This list was not created to point out the next confirmed epidemic. It is meant to identify the diseases for which research and development should be prioritized, as well as to point to pathogens that could present a major global health risk that are currently lacking in treatments or vaccines.
“Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease,” the WHO report stated.
There are precedents to follow — the world has had to confront new diseases many times before. SARS appeared in China in 2002, only to then spread around the world, and the Ebola outbreak in West Africa from 2014-2016 was the largest since it was first discovered in 1976. Most notably, the 1918 Spanish Flu infected an estimated 500 million people worldwide.
The opportunities for Disease X are endless and the ability to transmit diseases is becoming easier as the world becomes more and more connected.
“I was quite surprised not to find influenza there, to be honest,” pediatrician and infectious disease specialist Dr. Barbara Rath told Global Citizen.
Rath said that it is very possible that Disease X will end up being some type of influenza virus.
She pointed out that acute respiratory viruses transmit without much contact and because of this, people easily pass on sickness on subways, airplanes, and at mass gatherings.
“That’s what makes respiratory pathogens so nasty,” Rath added.
Influenza was not included in the main Blueprint list, but the WHO did reference it as one of the diseases that still poses a threat to public health and that its research and development is still important.
The UN Dispatch also suggested in an in-depth analysis that Disease X could be a type of flu. Avian influenza, for instance, can be transmitted from birds to humans, and while it cannot be passed from human to human right now, it could evolve.
“They're at least keeping their mind open that something poorly identified will come up,” Rath said of the WHO list.
In this case, a “poorly identified” disease means a disease that the world is lagging behind in finding ways to combat.
So even though the world has measures to fight influenza, for example, Rath still feels it poses a serious threat.
“[There is a] false perception that we already think we know how to manage it,” she said. “In practice, we don’t, we don’t understand it in many ways.”
In January 2017, the Coalition for Epidemic Preparedness Innovations (CEPI) officially launched during the World Economic Forum in Davos, Switzerland.
The CEPI was created to fill gaps in vaccine development and deployment in an effort to contain outbreaks as soon as possible.
In accordance with the 2017 WHO priority list, the CEPI’s focus was initially on the MERS-CoV, Lassa and Nipah viruses.
The WHO priority list provides a launching pad for research on diseases outlined as threats.
“Every flu season there is a chance to rehearse for it, and I’m still very sceptical if we have learned our lesson,” Rath said.
Still, some lessons have been learned. For example, the health community now knows to that Disease X could very likely come from an animal because of past cases.
HIV was initially found in chimpanzees, but eventually evolved to infect humans, the UN Dispatch reports.
Ebola was also passed to a human after a child was bitten by an infected bat in Guinea, according to UN Dispatch.
One possibility for Disease X is a disease called Brucellosis, a bacterial infection similar to tuberculosis, and it is found in an estimated 10% of farmed dairy cattle, according to UN Dispatch.
Currently, testing commercial dairy products prevents it from spreading to people, but raw milk consumption and a minor bacterial mutation could affect that protection.
Disease X could also be a new pathogen that might come from an animal reservoir. In Malaysia, fruit bats infected with the Nipah virus infected pigs, which in turn infected and killed humans in 1999. There wasn’t even any knowledge of this virus until 1998, according to UN Dispatch.
Another component working against vaccine and treatment research is the potential for Disease X to be created by humans as a weapon, according to the UN Dispatch.
Luckily, past epidemics have also taught the health community to react quicker in times of crises.
Being prepared to fight Disease X means being prepared to fight all diseases, which can be done by strengthening all health systems.