The Zika virus is transmitted between humans primarily by the infectious bite of the Aedes aegypti and A. albopictus species of daytime-feeding mosquito. The infection so caused emerged explosively in South America 18 months ago, with the primary impact of thousands of babies born with microcephaly, a serious neurological defect. Although the epidemic that was centred initially in Brazil has since spread throughout Latin America, the rate of its progress to other regions of the globe has not been as rapid as was first predicted. This has enabled the public health surveillance systems in countries in North America, Europe and the Asia Pacific region to be placed on high alert for the detection of clinical cases in, for instance, travellers returning from known Zika-endemic zones. This has contributed to reducing the likely future impact of Zika on regions that are not currently affected. This should act to dampen the media frenzy that accompanied preparation for the recent Rio de Janeiro Olympic and Paralympic Games concerning not only the local impact but the threat of a global pandemic. However, a significant caveat is that the geographical distribution of vector mosquitoes may be modified by climate change, with an incrementally increasing range; this should be monitored assiduously in order to prepare for the risk of local outbreaks in areas previously free of infection. It should be stressed that in developing countries situated in tropical and subtropical climates, where public health provision is not as well-established as in industrialised nations, there may remain a significant threat of Zika epidemics for years to come. On a positive note, a unified vector control and prevention strategy can encompass Zika and the closely related yellow fever, dengue and chikungunya arboviruses, which are all carried by the same Aedes mosquitoes. Thus, such a ‘one size fits all’ approach may help to combat the cause of several major tropical infectious diseases.
Andrew W Taylor-Robinson