The US National Institute of Allergy and Infectious Diseases has published a report suggesting any argument that the global Zika Virus pandemic has been brought under control is "premature".

Since the World Health Organisation declared Zika to be an international public health emergency in 2016, millions of people have been infected with the virus as it established itself in more than 80 countries.

The birth defects associated with the virus caught media and research attention all over the world, with images of newborns suffering from microcephaly -- a smaller than normal head -- becoming synonymous with the pandemic. Although some of its victims are obvious, many more children born in apparent good health will begin to show delayed effects of the infection as they mature into school age.

As such, the virus' true reach is yet to be seen.

The virus was first isolated in the Ziika Forest of Uganda in 1947, from which it took its name. Since 1950, outbreaks occurred in the narrow equatorial belt from Africa to Asia. The virus was generally considered an inconsequential virus before its incidence surged and it spread east across the Pacific Ocean to reach the Americas, carried by the Aedes aegypti mosquito; the same type that has transmitted yellow fever, dengue and chikungunya viruses across the world.

A vast body of research work has been compiled since the pandemic was first recognized in 2013, with this representing the first time that an epidemic of the fetal disease has been studied in real-time across South and Central America.

The Zika battle continues

In its report, the National Institute of Allergy and Infectious Diseases sets out some of the most important research goals.

Effective antiviral therapy -- used to kill or prevent the growth of the virus -- has not yet been developed, although several approaches, including repurposing existing drugs, are being investigated in preclinical studies. This is further complicated by the need to treat pregnant women and fetuses, requiring additional research and consideration.

Work to develop a Zika vaccine continue, with at least seven different vaccines currently involved in clinical trials, and a more than 40 others in preclinical development. However, the fact that the virus seems to be slowing and waning is a challenge to continued funding and attention.

Inactive diseases can re-emerge

The report stresses that Zika should not be considered a "one-time crisis" that has now been controlled. The authors note that the past 40 years have seen a new era of infectious disease, in which seemingly inactive or dormant disease (including the dengue and West Nile viruses) have aggressively reemerged on a global scale. The environmental and human factors that allowed Zika to emerge on such a scale and at such speed still exist, with the tropical and much of the temperate world still at risk from the disease, which has the potential to resurface unexpectedly and aggressively in future, be it near or far.