Lessons learned from new emerging infectious disease, Middle East Respiratory Syndrome coronavirus outbreak in Korea

Industrialization of transportation and human civilization has increased the frequency of travel and shortened the time of travel, resulting in many places around the globe within a day’s travel. Consequently, this human behavior has accelerated our risks for exposure to hitherto unknown pathogens. In the human history of epidemic outbreaks, whenever hosts and pathogens made contacts for the first time, they have responded each other vigorously progressing to evolutionary adaptations through natural selection; the pathogens to the direction to lower virulence to survive without killing their hosts; coordinately the hosts adapt through individual and collective strengthening of immunity against the pathogens. Until such an evolutionary equilibrium is established, the clash usually triggers high-mortality pandemic episodes. Thus, any new infectious disease is hence a formidable threat to human lives. Emergence of new pathogen, a mutant, and pathogen-host interaction may be different between various environments. In particular, changing environments that we are experiencing recently, may provide chances to rise new pathogenic mutants, which in turn provide opportunities of invading human hosts; for example people may pursue nature as a hobby by visiting jungles, deep seas, arctic regions, or in near future even other planets in the universe. In such cases, since the human body has not experienced these new pathogens in terms of immune system preparedness and response, the contact with new pathogens will result in massive occurrence of patients and deaths due to high infectivity, virulence and pathogenicity of the infectious agents. On the other hand, the infectious agent known through previously documented outbreaks, progressed to the certain degree of adaptation to human in other countries, such as the case with the recent Middle East Respiratory Syndrome (MERS) outbreak, should not pose any great problems, especially when even diagnostic tools have already been developed.