Scientists have found a potential treatment option for Zika that may protect babies from developing a severe birth defect, according to a new study from Yale University.
By unraveling exactly how the virus causes microcephaly—a condition where babies are born with abnormally small heads and, usually, underdeveloped brains—researchers at Yale were able to test out a few existing antiviral treatments, and found some early signs of success with two, according to a paper published Wednesday in Cell Reports.
"There is an urgent need to identify therapeutic approaches to halt Zika infection, especially in pregnant women," Marco Onorati, co-first author of the paper and a researcher at Yale, said in a press release. "In the interim, we hope these findings can lead to therapies that might minimize the damage caused by this virus."
Earlier this year, scientists confirmed that Zika can cause microcephaly, but they still weren't sure exactly how. Multiple studies have provided evidence that the Zika virus was damaging brain tissue, leading to microcephaly, but this latest research went a step further. By comparing neural stem cells in the lab with the brain tissue of a Zika-infected fetus that died from microcephaly, the team was able to find out how the Zika virus infects, damages, and kills the cells of a developing human brain.
The researchers found that the virus disrupts pTBK1, a protein that helps spur cell division in the growing brain. This causes the cells—which are essential for setting up the structure of the brain—to die, instead of multiply, and the virus also attacks these neural stem cells directly. Without these crucial cells, the brain isn't able to fully develop, and microcephaly occurs.
Armed with this new understanding, the researchers decided to test out a few existing antiviral treatments. Some of these treatments were ineffective on the lab cells, others actually made the infection worse, but two managed to stop the replication of Zika virus cells, protecting the neural stem cells from further damage. One of the treatments, Sofosbuvir, is already an FDA-approved drug used to treat Hepatitis C. Though this is promising, a lot more work needs to be done before a Zika treatment is confirmed, the researchers cautioned.
"To be succinct: Sofusbuvir is not, at present, a medication that people currently facing Zika should use," Marco Onorati, first author on the paper and a neuroscientist at Yale, told me via email. "Animal studies found no effect of Sofosbuvir on fetal development, but there have been no adequate studies of Sofosbuvir in pregnant women. Our studies would also need to be repeated, in vitro and in vivo, before we could be sure Sofusbuvir has an effect in Zika virus treatment and is safe."
Zika has been spreading rapidly throughout Latin America since the outbreak was first identified in Brazil last year. Currently, 56 nations are experiencing outbreaks, according to the CDC, and local transmission arrived in Miami earlier this summer. Though the vast majority of people infected with Zika have no symptoms, or only get a mild flu-like infection, Zika can cause microcephaly in some pregnant women and that threat has caused the greatest concern. Children born with microcephaly can have physical and developmental disabilities or face early death or miscarriage.
Luckily, research like this helps us understand how Zika works, which means even if Sofusbuvir isn't the right option, scientists now have a better chance at finding a treatment that does work. Combined with ongoing research on vector control and the rapid development of a vaccine, there's hope that future children can be protected from Zika.