Clues to Zika Damage Might Lie in Cases of Twins<br />Since identical twins share one placenta while fraternal twins almost always have separate placentas, Dr. Zatz and other experts suggested<br />that the Zika virus may have penetrated one placenta and not the other.<br />When João Lucas and his twin sister were born in August 2015, their mother, Neide Maria<br />Ferreira da Silva, was unaware he had microcephaly or brain damage, she said.<br />Determining why one twin became infected in the womb while the other did not may illuminate how Zika crosses the placenta, how it enters the brain,<br />and whether any genetic mutations make a fetus more resistant or susceptible to Zika infection.<br />Ms. da Silva was especially alarmed by João Lucas’s seizures, which made him "get purple"<br />and look "like his eyes were going to jump out." Sometimes he became so agitated, he would scratch himself in the face, Ms. da Silva said.<br />It took a month before she brought João Lucas to the geneticist, who said "his brain, it wasn’t like ours," Ms. da Silva, 42, recalled.
