Overview of Emerging Arboviruses

Ann M. Powers


Future Virology. 2009;4(4):391-401. 

In This Article

Future Perspective

Emergence of arboviruses will continue to occur. Alterations in ecological patterns and natural evolution of invertebrate vectors, vertebrate hosts and the viruses themselves combined with rapid movement of people and animals on a global scale will constantly generate conditions in which new pathogens emerge or are discovered. However, with recent advances in basic scientific knowledge of arboviruses, the scientific and public health communities can position themselves to be better prepared for these unexpected events. A tremendous example is how quickly the 'dengue-like illness' outbreak in Yap in 2007 was accurately diagnosed. The astute observations of local physicians in recognizing the subtle differences from previous dengue outbreaks were the first step. Next, rapid communication of the outbreak to networked public health officials led to shipping of samples to appropriate diagnostic facilities. Once there, the meticulous laboratory testing designed not only to look for the expected, but also the atypical agents, quickly confirmed that ZIKV was the infecting etiology.[104] Finally, the basic science that had been performed earlier, looking at genetic and antigenic variation among these closely related viruses,[105] was essential for development of the tests that were ultimately used in the diagnosis.

This rapid diagnostic testing, combined with pre-existing basic virological data, are critical components for the identification and control of future arboviral outbreaks. Given that most arboviruses have small genomes, it is not unrealistic to develop databases with extensive genetic information using rapid and large-scale sequencing options. Once developed, this database would be a fundamental tool in the development of molecular-based, rapid diagnostic tests, including real-time PCR,[106,107] microsphere/liquid-bead detection[108–110] and chip-based microarrays.[111,112] In addition, because many arboviral-like illnesses are caused by alternate etiological agents, shotgun sequencing and metagenomic analysis of a diverse array of pathogens will also aid in disease diagnosis.[113]

Timely detection of any pathogen during an epidemic, such that effective intervention strategies can be implemented, will always remain a public health challenge. While we cannot have every reagent for each of the 500 or more arboviruses stockpiled in every diagnostic laboratory, we can have the solid basic scientific foundation necessary to rapidly reach this point during an emergency. Most fundamental is the basic laboratory science of characterizing and understanding the viral genetics, antigenic properties, virulence patterns, vector associations and maintenance mechanisms. Next are the public health necessities, including providing public and clinician awareness of vector-borne diseases, ensuring that vector control options are available, maintaining adequate surveillance systems with trained personnel and providing necessary treatment.[114] A fully-integrated program incorporating the advances in laboratory science with highly refined surveillance programs designed to address all the components of the arboviral life cycle will be the best approach for detecting and controlling vector-borne diseases as they continue to appear. The tools are out there to be prepared for arboviral epidemics, now they just need to be used.