The Zika virus (ZIKV) infection is an iconic example of re‐emerging arboviral diseases. Observed as a human disease as early as in the 1950ies, it was identified as a major public health issue only in 2015, when imported in Latin America.

Clusters of microcephaly and neurological manifestations urged WHO to declare a ‘Public Health Emergency of International Concern’ on 1st of February 2016. Meanwhile, the causal relationship between ZIKV infection during pregnancy and microcephaly and other brain anomalies appears close to certain (Cauchemez et al., Lancet, 2016; Rasmussen et al., NEJM, 2016). ZIKV is continuing to spread in the Americas: as of 10 March 2017, 48 countries and territories have confirmed autochthonous, vector-borne transmission of Zika virus since 2015 (Figure 1). In addition, five countries in the Americas have reported sexually transmitted Zika cases (Argentina, Canada, Chile, Peru, and the United States of America).

 

Figure 1. Countries and territories in the Americas with confirmed autochthonous (vector-borne) Zika virus cases, 2015-2017.

© Copyright Pan American Health Organization (PAHO) & World Health Organization (WHO), 2017. All Rights Reserved.

 

Major tasks are ahead of the scientific and public health community and need urgent resolution, in particular:

  • the assessment of the scale of the problem ‐ absolute and relative risk of fetal damage in relation to time of infection during pregnancy, and postnatally;
  • understanding the natural history of the infection at different scales ‐ from cellular mechanisms to human infection and circulation of the virus in the environment.

These are essential prerequisites to the development of modes of prevention or treatment, to the assessment of the socioeconomic and disability burden of the disease, as well as to the implementation of informed public health decisions to reduce disease burden and the risk of further spread of the pandemic.