For many, the coronavirus disease 2019 (COVID-19) pandemic seemed to arrive out of the blue. However, a flu or coronavirus pandemic had been predicted in emerging disease literature for many years.1 Severe acute respiratory syndrome (SARS), another coronavirus, had pandemic potential when it emerged in 2002, but the swiftness of the incubation period likely helped halt any dramatic spread like the one seen with COVID-19.2

What SARS and COVID-19 have in common is that they are both zoonotic diseases (or zoonoses, which are diseases originating from animals) and are RNA viruses. SARS and the influenza A subtype H5N1 likely “jumped” from an animal reservoir.3 These types of viruses have higher mutation rates than DNA viruses, giving the virus a longer time to mutate into a strain humans are not immune to.4

A 2001 study by Cleaveland et al, which included a database of pathogens causing disease in humans and animals, recorded 1415 infectious pathogens that cause disease in humans, 61.6% of which were multihost pathogens. The authors wrote that RNA viruses were “a clear risk factor for disease emergence in humans and domestic mammals and for listing by the OIE [World Organisation for Animal Health].”4

Factors that play a role in interspecies pandemics include changes in the natural ecosystem, density of human settlement, and global trade.5

Carrasco-Hernandez et al6 assessed the patterns of previous zoonotic disease transmissions and posited that, “quantitative models that account for the localization of human disturbance will undoubtedly help predict future interspecies transmission events.” They advised that technology specifically designed for the survey and control of RNA viruses must be a research priority. They also noted the importance of continued monitoring of viral genetics and phenotypes in wildlife reservoirs. Taking a preventive survey program approach was suggested as a “best strategy” to protect against viral diseases. “Conservation policies that control the disturbance of natural ecosystems are also essential,” the authors concluded.

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The impact of COVID-19 on the global health system and economy will likely result in large-scale changes in zoonotic disease prevention preparedness. A 2017 article in the CDC’s Emerging Infectious Diseases7 highlighted how in most countries, “animal health and human health decision makers are located within different ministries.” Therefore, to help with preparedness the authors suggested improving surveillance and data sharing. “Establishing multisectoral One Health partnerships across agencies and with interdisciplinary personnel at the national, subnational, and local levels […] can strengthen zoonotic disease detection and response activities.” In their conclusion, the authors stressed that these structures must be in place before a pandemic occurs to have an effective, coordinated public- and animal-health response.


  1. Hunter P. Inevitable or avoidable? Despite the lessons of history, the world is not yet ready to face the next great plague. EMBO Rep. 2007;8(6):531-534.doi: 10.1038/sj.embor7400987
  2. Severe acute respiratory syndrome (SARS); frequently asked questions about SARS. Centers for Disease Control and Prevention website. Reviewed May 3, 2005. Accessed April 28, 2020.
  3. SARS (severe acute respiratory syndrome). World Health Organizationwebsite. Accessed April 28 2020.
  4. Cleaveland S, Laurenson MK, Taylor LH. Diseases of humans and their domestic mammals: pathogen characteristics, host range and the risk of emergence. Philos Trans R Soc London B Biol Sci. 2001;356(1411):991-999. doi: 10.1098/rstb.2001.0889
  5. Hassell JM, Begon M, Ward MJ, Fѐvre EM. Urbanization and disease emergence: dynamics at the wildlife-livestock-human interface. Trends Ecol Evol. 2017;32(1):55-67. doi:10.1016/j.tree.2016.09.012
  6. Carrasco-Hernandez R, Jácome R, López Vidal Y, Ponce de León S. Are RNA viruses candidate agents for the next global pandemic? A review. ILAR J. 2017;58(3):343-358. doi:10.1093/ilar/ilx026
  7. Belay ED, Kile JC, Hall AJ, et al. Zoonotic disease programs for enhancing global health security. Emerg Infect Dis. 2017;23(suppl). doi:10.3201/eid2313.170544