From "A"IV to "Z"IKV: Attacks from Emerging and Re-emerging Pathogens

Abstract

100 years after the infamous "Spanish flu" pandemic, the 2017-2018 flu season has been severe, with numerous infections worldwide. In between, there have been continuous, relentless attacks from (re-)emerging viruses. To fully understand viral pathogenesis and develop effective medical countermeasures, we must strengthen current surveillance and basic research efforts.

Figure 1

Human Infections with Subtypes of Influenza A Viruses The numbers of human cases infected by different subtypes of influenza A virus reported worldwide are shown in histogram (WHO, 2017a). The x axis presents the time points (year) of the first reported case for each subtype virus. The y axis presents the total numbers of reported human cases to date. The case numbers of human-infecting H1N1, H2N2, and H3N2 are extraordinarily large and are not available for exact counts due to influenza pandemics such as the 1918 H1N1 Spanish flu, 1957 H2N2 Asian flu, and 1968 H3N2 Hong Kong flu.

Figure 2

Geographical Distribution of Zika Virus Infections, Addressing the Spread of the 2015 Brazil Outbreak Locations where big events of Zika virus infection occurred were indicated in red. These events are described in boxes and numbered according to the time sequence. The dashed arrow lines represent the spreading routes of Zika virus during the 2015–2016 outbreak. Regions with evidence of Zika virus transmission are colored in yellow, except for the five red-colored ones as mentioned above. China is colored in light yellow due to the imported cases in 2016 and the isolation of Zika virus in local vector, although not in the 84 countries with Zika virus transmission according to the WHO classification (WHO, 2017b).