This image compares the brain of a baby that has developed normally (top), the brain of a baby that has developed primary microcephaly (middle), and the brain of a baby from Brazil whose mother contracted Zika virus during her pregnancy (bottom). The bottom image indicates several abnormalities, including a severe reduction in brain size, excess fluid around the brain (external hydrocephalus) and calcifications in the brain tissue that indicate abnormal brain development. IMAGE CREDIT: Dr. Lavinia Schuler-Faccini, Genetics Department, Federal University in Porto Alegre, Brazil.

This image compares the brain of a baby that has developed normally (top), the brain of a baby that has developed primary microcephaly (middle), and the brain of a baby from Brazil whose mother contracted Zika virus during her pregnancy (bottom). The bottom image indicates several abnormalities, including a severe reduction in brain size, excess fluid around the brain (external hydrocephalus) and calcifications in the brain tissue that indicate abnormal brain development. IMAGE CREDIT: Dr. Lavinia Schuler-Faccini, Genetics Department, Federal University in Porto Alegre, Brazil.

New research out today in the journal Cell Stem Cell indicates a likely link between the Zika virus and abnormal brain development. Scientists are studying if the spread of Zika by mosquitoes in Latin America is linked to the increased rates of microcephaly, a condition in which babies are born with unusually small heads. The study was conducted by researchers at the Johns Hopkins University School of Medicine, Florida State University and Emory University.

Dr. William Dobyns, a pediatric neurogeneticist at the Center for Integrative Brain Research at Seattle Children’s Research Institute who treats and studies microcephaly, sat down with On the Pulse to discuss the new research published today.

Q: Does this new study published today indicate a link between the Zika virus and microcephaly in newborns?

Dobyns: The scientists who did this work confirmed that when developing brain cells are exposed to the Zika virus, it interferes with normal brain development.

The scientists studied what would happen if neural stem cells, which are the basic building blocks of a developing brain, were exposed to the Zika virus. These neural stem cells give rise to neurons and provide the scaffolding that allows the rest of the brain to develop properly. When neural stem cells do not develop normally, it interferes with brain development.

The paper showed that the 90% of neural stem cells exposed to Zika were infected and began to make copies of the virus. Many of the cells died or were unable to divide and create normal brain cells.

Q: What does this research mean for the scientific community studying the Zika virus?

Dobyns: This research helps scientists understand how the Zika virus could be leading to the birth defects we are seeing. It gives us a path to research drugs and vaccines to prevent Zika infection from causing brain defects. We can also begin to look at using animal models to observe how Zika virus impacts the developing brain.

There has not been much scientific work in the past to develop a vaccine for Zika because in adults the virus has typically caused only mild symptoms. In light of the link to birth defects, there is an urgency that we need a vaccine or drug intervention to keep the virus and its potential damage to newborns from spreading further.

Q: Are there other viruses that cause these brain defects in newborns?

Dobyns: I have observed only one other virus that can cause this severity of brain defects in newborns, and that is cytomegalovirus (CMV). Similar to the Zika virus, CMV attacks developing neural stem cells, which results in abnormal brain development.

I am working with colleagues in Brazil to review brain scans of babies with microcephaly, and we are seeing a regular pattern of very severe brain defects. I have been studying microcephaly for decades and until this sudden increase, I have only seen such severe brain defects a few times in my career.

Q: What can be done for babies who are born with severe microcephaly?

Dobyns: These babies have severe brain defects and face severe developmental disabilities. They will need intense and early therapeutic interventions including feeding therapy, physical therapy and occupational therapy to improve their quality of life.

While people have not yet contracted Zika in the U.S., it is only a matter of time before it arrives in the southern parts of the country. I would strongly caution women who are pregnant or considering becoming pregnant against traveling to countries with known Zika virus outbreaks. I would encourage travelers, especially women of childbearing age, to check with their physicians and check the Centers for Disease Control travel advisories on Zika virus.

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