Disease X

The recent outbreak in the Democratic Republic of Congo (DRC), which has claimed over 400 lives and remains unclassified, has raised concerns that it could be an instance of Disease X. It shows the global vulnerability to unknown pathogens, underscoring the importance of being prepared for such unpredictable threats.

What is Disease X?

• Disease X is a term coined by the World Health Organization (WHO) in 2018 to refer to a hypothetical, yet-to-be-discovered pathogen that could cause a global pandemic.
• It was introduced to raise awareness and prepare for diseases that are difficult to predict or identify but have the potential to create severe health crises.
• The WHO’s Blueprint for Priority Diseases, published in 2018, includes Disease X as a placeholder for unknown pathogens with epidemic potential, emphasizing the need for readiness to respond to emerging infectious diseases.
• Origin of the Concept: The idea of Disease X emerged in the wake of the 2014-2016 Ebola outbreak in West Africa, which exposed significant gaps in global epidemic preparedness. The WHO recognized that future outbreaks could arise from unknown pathogens, so it created Disease X as a framework for preparing for the unknown.
  • COVID-19 is often seen as the first actual example of Disease X, with the emergence of the SARS-CoV-2 virus in 2019 representing the unpredictable threat that Disease X was meant to address. The pandemic demonstrated how a novel pathogen could rapidly spread worldwide, overwhelming health systems and economies.

WHO's Priority List of Pathogens

• The WHO maintains a priority list of pathogens to guide global research and resource allocation.
• This list includes diseases that pose significant risks of spreading globally but have insufficient preventive measures, such as vaccines or treatments.
• The pathogens on the list include well-known diseases like Ebola, Marburg virus, Zika, Nipah virus, and Lassa fever, as well as Disease X.
• These diseases are selected based on factors such as:
  • High mortality rates.
  • Rapid transmission potential.
  • Lack of adequate vaccines or treatments.

Why Is Disease X a Growing Concern?

While the exact nature of Disease X remains unknown, there are several factors that contribute to the likelihood of its emergence:

• Zoonotic Spillover: Many emerging infectious diseases, including COVID-19, are zoonotic, meaning they are transmitted from animals to humans. Activities such as deforestation, urbanization, and agriculture are pushing humans into closer contact with wildlife, increasing the risk of zoonotic diseases.
• Environmental and Ecological Disruptions: Human-induced changes to the environment, such as climate change, are reshaping disease transmission dynamics, with vector-borne illnesses like malaria and dengue expanding into new regions.
• Antimicrobial Resistance (AMR): The growing threat of antimicrobial resistance, where pathogens evolve to resist existing drugs, could make responding to new outbreaks more challenging.
• Global Connectivity: Increased international travel and trade mean that localized outbreaks can rapidly become global pandemics, as seen with COVID-19.

Challenges in Predicting Disease X

Predicting the exact origin or timing of Disease X is extremely difficult because its emergence depends on many unpredictable factors, including:

• Mutations in existing pathogens.
• Laboratory accidents or bioterrorism.
• Climate change affecting the behavior and spread of diseases.

Scientists estimate that there are over 1.7 million undiscovered viruses in wildlife, with many potentially capable of infecting humans. Only a fraction of these pathogens have been identified, leaving the world vulnerable to emerging threats.