'Disease X' could be a new agent - a virus, a bacterium or fungus.
Covid-19 posed unprecedented challenges before the world, and caused thousands of fatalities. Scientists scrambled to create a vaccine to take on the virus that spread quickly since its outbreak in 2019. After three years, a sense of normalcy has returned but scientists are wary of the next outbreak, especially after World health Organisation (WHO) chief's recent statement that the world must get ready for the next pandemic, which might be "even deadlier" than Covid-19. After this remark, there is a renewed interest in the list of 'priority disease' on the health body's website.
The short list has the names of the disease that could cause the next deadly pandemic. While most of the diseases are known to us - Ebola, Sars and Zika - the final entry named 'Disease X' has caused concern.
According to WHO website, the term "represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease".
It could be a new agent - a virus, a bacterium or fungus - without any known treatments.
The WHO started using the term in 2018. And a year later, Covid-1 began to spread across the world.
"It is not an exaggeration to say that there is potential of a Disease X event just around the corner," Pranab Chatterjee, researcher at the Department of International Health at Johns Hopkins Bloomberg School of Public Health in Baltimore, told The National Post.
"The recent spate of H5N1 bird flu cases in Cambodia is just a case in point," he added.
The term has led to deliberations across the world, with many experts claiming that the next Disease X will be zoonotic, like Ebola and Covid-19.
Others said the pathogen could also be created by humans.
"The possibility of an engineered pandemic pathogen also cannot be ignored," said the authors of a 2021 article in the journal Infection Control & Hospital Epidemiology.
The other priority diseases on the WHO list include Marburg virus, Crimean-Congo hemorrhagic fever, Lassa fever, Nipah and henipaviral diseases, Rift Valley fever and Middle East respiratory syndrome.
For now, health experts want surveillance to be increased and additional funds provided to develop counter measures.