Yes, it is incredibly intriguing for scientists to launch their hypotheses about new and emerging illnesses, but it's also imperative to envisage what kind of template it imprints on the brains of ordinary people. For the average person, since the advent of COVID-19, every disease appears to have analogous dynamics to COVID-19. However, it's crucial to understand that COVID-19 was neither the first pandemic to strike the world nor the last, making it necessary for us to get ready for circumstances akin to COVID-19. One notable pandemic is the Spanish Flu, which killed a total of 50 million to 100 million individuals worldwide. Therefore, almost one new disease emerges each year with enigmatic penalties. But we have to understand that not all diseases have human-to-human transmission, but enough can (such as severe acute respiratory syndrome, Middle East respiratory syndrome, and Ebola virus illness) to frighten those who are in charge of keeping a watchful eye on global public health.

To emphasise the hazard and to prioritise research, the World Health Organization (WHO) updates its yearly list of the most dangerous infectious diseases for which there are no vaccines or viable treatments available. One such disease is now under the scanner of the WHO and other global health authorities, which is named "Disease X". According to the World Health Organization (WHO), "Disease X represents the knowledge that a serious international epidemic or pandemic could be caused by a pathogen currently unknown to cause human disease." Although it seems like science fiction, if it unfolds, we won't have enough time for its preparedness. In this regard, health professionals have issued warnings that a new pandemic could be just around the corner. The proposition has been made based on an exponential rise in the number of cases of various infectious diseases over the past six months, including the appearance of monkey pox in Britain and the discovery of the poliovirus in sewage samples from London, UK, despite the absence of any clinical cases of polio in this region.

Similarly, in the last year, increased incidences of bird flu, Crimean-Congo hemorrhagic fever, and Lassa fever have been reported from different parts of the globe. In conjunction with this, healthcare experts from many western nations have issued a warning and urged administrative bodies to prepare for Disease X. The World Health Organization (WHO) has defined Disease X as the possibility of a severe pandemic that could be caused by a pathogen that is currently non-pathogenic to humans. Furthermore, according to the W.H.O., disease "X" might cause a catastrophic outbreak that could spread across many countries. It is nearly impossible to identify a specific organism as the epidemic's cause, despite numerous well-known epidemiologists predicting that a fresh outbreak will either be caused by influenza or measles. According to the Eco Health Alliance, a U.S.-based organization, there are approximately 1.67 million undiscovered viruses on the planet, with 827,000 of them capable of causing disease. Some specialists hypothesised that the COVID-19 in December 2019 and the Zika virus outbreak fit the requirements for being termed Disease X, but these two illnesses do not fulfil the essential prerequisite of being lethal and deadlier in their clinical outcomes. Disease X is supposed to be caused by a "pathogen X". Such a pathogen is projected to be a zoonotic pathogen, most likely an RNA virus, and is predicted to arise from a place where the proper triad of risk factors significantly raises the likelihood of on-going transmission. While it's important to keep an eye out for emerging zoonotic pathogens, the prospect of an engineered pathogen specifically for a pandemic cannot be discounted either. It has been noted that the release of such pathogens, whether through laboratory mishaps or as a result of bioterrorism, poses a cataclysmic risk of Disease X for the entire world.

Global studies have suggested that factors such as rapid urbanization, environmental degradation, and climate change may act as catalysts for the emergence of new pandemics like Disease X. The argument put out is that these changes would relocate wild animals from their natural habitat, thereby increasing man-animal conflict. This argument is proven by the fact that the human population is expanding quickly and encroaching on wild areas. So, there is always a risk that a pathogen will jump from wild animals and then infect humans. According to the opinions of different healthcare experts, disease X would be as severe as the "black death," which nearly killed 80 million people. A recent study published in Nature Communication posited that the emerging infectious diseases might originate in Southeast Asia, Africa, or Australia, and that these regions might act as disease hotspots. Disease X presents the worst-case scenario by being extremely contagious and deadly, which may lead to its spread over the world and would result in millions of deaths before any action could be taken.

Despite the dire circumstances, it is possible to effectively control the spread of Disease X and its negative effects on human health and the economy. To do this, we must take several crucial steps, including developing and implementing international guidelines to control bioterrorism; approving the academic and scientific advice of knowledgeable academicians and researchers without political interference; imposing immediate and appropriate travel restrictions and conducting airport screening across borders for containment of pathogen X; accomplishing collaborative research with different scientists of diverse backgrounds; developing sensitive and precise diagnostic tools for mass screening and effective contact tracing; receiving funding in the research and development field to conduct clinical trials; developing vaccines and other therapeutics and biologicals; and conducting active surveillance of virus laboratories to prevent the possible leakage of a new virus.

These steps can be implemented effectively under the auspices of one health approach, so in this direction, the Coalition for Epidemic Preparedness Innovations (CEPI), an alliance to finance and coordinate the development of new vaccine prototypes for the containment of upcoming epidemics, has started their rapid response program. If Disease X appears, these prototypes can be developed into potential vaccine candidates, enabling rapid and effective disease containment that would revolutionise efforts to prevent future pandemics. Although we still don't know where or when disease X will come into contact with humans, we know from our prior experience with COVID-19 that epidemics do not respect geographic boundaries. Therefore, the greatest thing we can do is equip ourselves with logistical support that will help us combat disease X. Therefore, one health approach offers a comprehensive way to address cross-sectoral problems by bridging institutional gaps, listing priority risk areas and pathogens, and highlighting prima facie risk factors for subsequent spillover events involving emerging and re-emerging infectious disease microbes at the human-animal-environment interface.

Lastly, the take-home message of the discussion is that we must amplify the bulwarks before the next novel pathogen X comes knocking on our doors. Joshua Lederberg, the Nobel laureate, rightly stated, "The future of humans and microorganisms will likely unfold like episodes of a suspense drama with the working title "Our Wits Versus Their Genes."

(Dr Abrar Ul Haq Wani is Assistant Professor cum Junior Scientist, Dept. of Medicine, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab; Email: dr.abrar79@gmail.com. Dr Showkat Ul Nabi is Scientist, Dept of Veterinary Medicine, SKUAST-K; Email: showkatnabi@gmail.com. Dr Syed Quibtiya is Associate Professor, Department of General Surgery, SKIMS Medical College, Bemina, Srinagar; Email: drquibtiya@yahoo.com . Dr Naveed Nazir Shah is Professor & HOD, Chest disease Hospital, GMC, Srinagar; Email: naveednazirshah@yahoo.com)