Disease X: Exploring the Unexplored, Knowable Unknown

  • Rina Tilak Scientist ‘G’, Armed Forces Medical College, Pune, India.
  • Sajal Bhattacharya Professor (Associate), Postgraduate Department of Zoology, Asutosh College (University of Calcutta), Kolkata, West Bengal, India.
  • VW Tilak Ex Dean, Armed Forces Medical College, Pune, India.
  • Shakya Sinha Research Scholar, Postgraduate Department of Zoology, Asutosh College (University of Calcutta), Kolkata, West Bengal, India.
Keywords: Disease X, Pandemics, Surveillance, Bio-weapons, Blueprint Priority Diseases


The glaring uncertainty regarding the identity of certain pathogenic bio-agents having potential for a severe global public health security threat has spurned the international health agencies to classify it as Disease X, which has been added to the “blueprint priority diseases” as a placeholder name for a “knowable unknown” pathogen by the WHO. The zoonotic diseases of viral origin and the synthetic viruses are acknowledged as the most likely agents of Disease X causing public health emergencies of international concern in times to come. The challenges in the rapid containment of Disease X pandemics could be the inability for early detection of the infectious agents, presence of a large immunologically naïve population, lack of knowledge of clinical spectrum, no pathogen-specific effective drugs and/ or vaccines and sudden surge of patients requiring hospitalisation which collectively compromise the public health system especially in resource stricken countries and leads to its eventual collapse. Well-equipped field laboratories, sentinel surveillance centres for viruses and other microbial pathogens are needed in strategically important and sensitive areas of concern for monitoring for early detection of possible bio-agents of Disease X, if any. In a changing geo-socio political scenario, use of the synthetic viruses as a potential bio-weapon for mass destruction and/ or for the economic breakdown of a targeted country should not be ruled out. Thus, capacity building, global technical collaboration and stringent international regulations to prevent the development of bio-weapons are also obligatory to prevent any possible future pandemics of Disease X.

How to cite this article:
Tilak R, Bhattacharya S, Tilak VW, Sinha S. Disease X: Exploring the Unexplored, Knowable Unknown. J Commun Dis. 2021;53(4):135-139.

DOI: https://doi.org/10.24321/0019.5138.202183


Bhattacharya S. Mosquito borne diseases in India with special reference to malaria vectors and their control. J Asiatic Soc. 2009;L1(2):15-34.

World Health Organization [Internet]. 2018 Annual review of diseases prioritized under the Research and Development Blueprint. Geneva, Switzerland; 2018 [cited 2021 Nov 30]. Available from: https://www.who.int/docs/default-source/blue-print/2018-annual-review-of-diseases-prioritized-under-the-research-and-development-blueprint.pdf?sfvrsn=4c22e36_2

World Health Organization [Internet]. Prioritizing diseases for research and development in emergency contexts; 2021 [cited 2021 Nov 30]. Available from: https://www.who.int/activities/prioritizing-diseases-for-research-and-development-in-emergency-contexts

Friedrich MJ. WHO’s blueprint list of priority diseases. JAMA. 2018 May;319(19):1973. [PubMed] [Google Scholar]

Simpson S, Kaufmann MC, Glozman V, Chakrabarti A. Disease X: Accelerating the development of medical countermeasures for the next pandemic. Lancet Infect Dis. 2020 May;20(5):e108-15. [PubMed] [Google Scholar]

Jiang S, Shi ZL. The first disease X is caused by a highly transmissible acute respiratory syndrome coronavirus. Virol Sin. 2020 Jun;35(3):263-5. [PubMed] [Google Scholar]

Carroll D, Daszak P, Wolfe ND, Gao GF, Morel CM, Morzaria S, Pablos-Méndez A, Tomori O, Mazet JAK. The global virome project. Science. 2018;359(6378):872-4. [PubMed] [Google Scholar]

Woolhouse M, Scott F, Hudson Z, Howey R, Chase-Topping M. Human viruses: discovery and emergence. Philos Trans R Soc Lond B Biol Sci. 2012 Oct;367(1604):2864-71. [PubMed] [Google Scholar]

Woolhouse ME, Adair K, Brierley L. RNA viruses: a case study of the biology of emerging infectious diseases. Microbiol Spectr. 2013 Oct;1(1):10. [PubMed] [Google Scholar]

Jones KE, Patel NG, Levy MA, Storeygard A, Balk D, Gittleman JL, Daszak P. Global trends in emerging infectious diseases. Nature. 2008 Feb;451:990-3. [PubMed] [Google Scholar]

Louca S, Mazel F, Doebeli M, Parfrey LW. A census-based estimate of Earth’s bacterial and archaeal diversity. PLoS Biol. 2019 Feb;17(2):e3000106. [PubMed] [Google Scholar]

World Health Organization [Internet]. Antibiotic resistance; 2020 [cited 2021 Nov 30]. Available from: https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance#:~:text=Antibiotic%20resistance%20occurs%20when%20bacteria,caused%20by%20non%2Dresistant%20bacteria

Heather JM, Chain B. The sequence of sequencers: The history of sequencing DNA. Genomics. 2017 Jan;107(1):1-8. [PubMed] [Google Scholar]

Chatterjee R, Bhattacharya S. Could novel corona virus (SARS-CoV-2) be the evolving face of a new generation of genetically complex epidemiological challenges? Malaysian J Med Res. 2020;4(2):49-52. [Google Scholar]

Stauft CB, Wimmer E. Synthetic viruses. John Wiley & Sons, Ltd; 2019;1-7.

Bhattacharya S, Sinha S, Tilak R, Mardihusodo SW. The relationship between bats and human coronavirus: an exploratory review. J Health Soc Sci. 2020;5(2):219-30. [Google Scholar]

Tilak R, Bhattacharya S, Sinha S. Genotype 4 reassortant Eurasian avian-like H1N1 swine flu virus: an emerging public health challenge. Asian Pac J Trop Med. 2021;14(3):97-8. [Google Scholar]

Bhattacharya S. Challenges of mosquito-borne diseases in the changing ecological conditions. J Asia Soc. 2011;LIII(3):109-18.

Bhattacharya S, Sinha S, Baidya D, Tilak R. Emergence of a zoonotic pathogen - novel Coronavirus (SARS-CoV-2) in the context of changing environment. J Commun Dis. 2020;52(2):18-24. [Google Scholar]

Allen T, Murray KA, Zambrana-Torrelio C, Morse SS, Rondinini C, Di Marco M, Breit N, Olival KJ, Daszak. Global hotspots and correlates of emerging zoonotic diseases. Nat Commun. 2017 Oct;8(1):1124. [PubMed] [Google Scholar]

World Health Organization [Internet]. WHO Director-General’s remarks at the 1st virtual meeting of the One Health High Level Expert Panel - 17 May 2021; [cited 2021 Nov 30]. Available from: https://www.who.int/director-general/speeches/detail/who-director-general-s-remarks-at-the-1st-virtual-meeting-of-the-one-health-high-level-expert-panel-17-may-2021

Monath TP. Dengue: the risk to developed and developing countries. Proc Natl Acad Sci U S A. 1994 Mar;91(7):2395-400. [PubMed] [Google Scholar]

Jones KE, Patel NG, Levy MA, Storeygard A, Balk D, Gittleman JL, Daszak P. Global trends in emerging infectious diseases. Nature. 2008;451:990-3. [PubMed] [Google Scholar]