Caption: An NCATS researcher dispenses Zika virus into trays for compound screening in a lab using procedures that follow strict biosafety standards. Credit: National Center for Advancing Translational Sciences, NIH
In response to the health threat posed by the recent outbreak of Zika virus in Latin America and its recent spread to Puerto Rico and Florida, researchers have been working at a furious pace to learn more about the mosquito-borne virus. Considerable progress has been made in understanding how Zika might cause babies to be born with unusually small heads and other abnormalities and in developing vaccines that may guard against Zika infection.
Still, there remains an urgent need to find drugs that can be used to treat people already infected with the Zika virus. A team that includes scientists at NIH’s National Center for Advancing Translational Sciences (NCATS) now has some encouraging news on this front. By testing 6,000 FDA-approved drugs and experimental chemical compounds on Zika-infected human cells in the lab, they’ve shown that some existing drugs might be repurposed to fight Zika infection and prevent the virus from harming the developing brain . While additional research is needed, the new findings suggest it may be possible to speed development and approval of new treatments for Zika infection.
Caption: Zika virus (red), isolated from a microcephaly case in Brazil. The virus is associated with cellular membranes in the center. Credit: NIAID
Last February, the World Health Organization declared a public health emergency over concerns about very serious birth defects in Brazil and their possible link to Zika virus. But even before then, concerns about the unprecedented spread of Zika virus in Brazil and elsewhere in Latin America had prompted NIH-funded scientists to step up their efforts to combat this emerging infectious disease threat. Over the last year, research aimed at understanding the mosquito-borne virus has progressed rapidly, and we now appear to be getting closer to a Zika vaccine.
In a recent study in the journal Nature, researchers found that a single dose of either of two experimental vaccines completely protected mice against a major viral strain responsible for the Zika outbreak in Brazil . Caution is certainly warranted when extrapolating these (or any other) findings from mice to people. But, taking into account the fact that researchers have already developed safe and effective human vaccines for several related viruses, the new work represents a very encouraging milestone on the road toward a much-needed Zika vaccine for humans.
Caption: Human neural progenitor cells (gray) infected with Zika virus (green) increased the enzyme caspase-3 (red), suggesting increased cell death. Credit: Sarah C. Ogden, Florida State University, Tallahassee
Recently, public health officials have raised major concerns over the disturbing spread of the mosquito-borne Zika virus among people living in and traveling to many parts of Central and South America . While the symptoms of Zika infection are typically mild, grave concerns have arisen about its potential impact during pregnancy. The concerns stem from the unusual number of births of children with microcephaly, a very serious condition characterized by a small head and damaged brain, coinciding with the spread of Zika virus. Now, two new studies strengthen the connection between Zika and an array of birth defects, including, but not limited to, microcephaly.
In the first study, NIH-funded laboratory researchers show that Zika virus can infect and kill human neural progenitor cells . Those progenitor cells give rise to the cerebral cortex, a portion of the brain often affected in children with microcephaly. The second study, involving a small cohort of women diagnosed with Zika virus during their pregnancies in Rio de Janeiro, Brazil, suggests that the attack rate is disturbingly high, and microcephaly is just one of many risks to the developing fetus. 
For decades, the mosquito-transmitted Zika virus was mainly seen in equatorial regions of Africa and Asia, where it caused a mild, flu-like illness and rash in some people. About 10 years ago, the picture began to expand with the appearance of Zika outbreaks in the Pacific islands. Then, last spring, Zika popped up in South America, where it has so far infected more than 1 million Brazilians and been tentatively linked to a steep increase in the number of babies born with microcephaly, a very serious condition characterized by a small head and brain . And Zika’s disturbing march may not stop there.
In a new study in the journal The Lancet, infectious disease modelers calculate that Zika virus has the potential to spread across warmer and wetter parts of the Western Hemisphere as local mosquitoes pick up the virus from infected travelers and then spread the virus to other people . The study suggests that Zika virus could eventually reach regions of the United States in which 60 percent of our population lives. This highlights the need for NIH and its partners in the public and private sectors to intensify research on Zika virus and to look for new ways to treat the disease and prevent its spread.