The World Health Organization has declared the Zika virus and its potential link to birth defects a global health emergency. Zika virus is carried mainly by a species of mosquito called Aedes aegypti.

The World Health Organization has declared the Zika virus and its potential link to birth defects a global health emergency. Scientists are studying if the spread of Zika in Latin America is linked to the increased rates of microcephaly, a condition in which babies are born with unusually small heads. Zika virus is transmitted mainly through the bite of an infected Aedes aegypti or Aedes albopictus mosquito.

Dr. William Dobyns and Dr. Ghayda Mirzaa are pediatric neurogeneticists and researchers at the Center for Integrative Brain Research at Seattle Children’s Research Institute who treat and study microcephaly. On the Pulse sat down with them to discuss microcephaly.

Q: What is microcephaly?

Mirzaa: Microcephaly is a condition in which a fetus or baby’s head size is abnormally small, defined as more than two standard deviations below average. The smaller head size reflects abnormal or decreased brain growth. Microcephaly affects about 2% of newborns, while severe microcephaly, defined as a head size more than three standard deviations below average, is seen in less than 0.1% of newborns.

Microcephaly occurs as the only birth defect in many children, but it can also occur with a wide range of additional abnormalities including other brain defects. When a baby has microcephaly, a neurologist or geneticist will order tests to determine the cause. Read full post »