Emerging viruses: host immunity and novel therapeutic interventions

The inevitable emergence of novel infectious viruses and their unpredictable pathogenicity, transmissibility, and pandemic potentials are a major threat to human health. In particular, highly pathogenic influenza A viruses (IAVs), severe acute respiratory syndrome- and Middle East respiratory syndrome-coronavirus (SARS-CoV; MERS-CoV), Ebola virus (EBOV), and mosquito-borne Zika virus (ZIKV; Flavivirus) have attracted the world's attention due to their high pathogenicity, transmission and high mortality. While these viruses are mostly found in animals they can cause diseases and death in humans (zoonosis) when transmitted via close contact. Transmission of these pathogens is likely worsened by globalization and close quarter living in densely populated areas, all of which promotes rapid virus evolution and pandemic potential in humans. Significant research has resulted in deeper understanding of the virology, virus-host interactions, and disease pathology. These investigations have led to the development of vaccines and antiviral drugs, particularly for IAVs, and experimental vaccines for EBOV. Nevertheless, rapid and frequent virus mutations/reassortment often render current therapeutics ineffective, highlighting the limitations of our current therapeutic design strategies. Development of novel prevention and treatment options against these continuously mutating viruses must be explored before the next pandemic occurs.