Emerging infectious RNA viruses with a focus on Zika virus

Abstract

Abstract Introduction. The emergence of RNA viruses within the last few decades has become an increasing global public health concern. Most recently, documented cases of infection with the flavivirus Zika have been rising to epidemic proportions and its geographical range has been increasing. This virus causes disabling neurological complications and congenital defects and worryingly is the first arbovirus (vector transmitted) of the flavivirus family to have a reported human-human transmission. Aim. This narrative review aims to explore the history, evolution, epidemiology, virology, transmission and management of Zika virus, with the intention of presenting a summary of current evidence that can be used to enable prediction of future emergence. It will also aid in guiding public health initiatives and research. Methods. Online electronic databases of MEDLINE and EMBASE were searched in August 2019 using an exploratory range of search terms. This was also supplemented by Google Scholar searching. Articles were restricted to those published in the English language and subjected to peer review. No restrictions were placed on date of publication and primary sources of information were used where possible. Results/Discussion. The information acquired was considered under five main concepts of 1) virus history and evolution, 2) virology, 3) transmission and vector characteristics, 4) epidemiology and current emergence patterns and 5) management and prevention. Evaluation of the evidence highlighted the difficulties in predicting the emergence of Zika virus given that travel is one of the main routes of intercontinental spread. Longer-term emergence may follow rising global temperatures where new infestations of the vector Aedes aegypti mosquito may lead to outbreaks and epidemics within regions of borderline temperate conditions. Conclusion. Although the emergence of Zika virus is challenging, it is imperative that public health initiatives aim to support the prevention of virus transmission. This might best be achieved through eliminating Aedes mosquito breeding grounds, educating individuals regarding mosquito bite prevention and also making the public aware of the sexual and vertical transmission of Zika. Vaccination will be the ultimate great hope for this disease and trials are currently underway. These may prove safe and effective in conferring herd immunity for high-risk populations in the future.