Scientists have conducted a new study that says that a change in the Zika virus now attacks developing baby brain cells while still unborn and that is why babies in South America are born with tiny heads. The mutation only changed one amino acid in a protein that a gene tells the cell to create. This now changed protein helps the virus kill brain cells easily. Scientist believe that this change happened around May 2013. The virus has been around for awhile but never had the effect of causing unborn babies heads to become abnormally small until the Brazil outbreak in 2015 and 2016. Pei-Yong Shi is a virologist at the University of Texas Medical Branch at Galveston who says that researchers didn’t understand why this was happening now. They had been coming up with different theories as to why this was happening but Pei-Yong Shi and his team thought otherwise. They believed that Zika itself had changed to cause such a change in one of the ways it affects its victims. What they did was they compared a strain of the virus from a person who had contracted the virus to three other strains. One came from patients from 2015 or 2016 from Venezuela, some from Samoa, and lastly from Martinique. They then made seven different types of the Cambodian virus. Of all the different types of new virus, they added only one of the different gene viruses. The new viruses killed baby mice brain cells than the original Cambodian one had done before. It also showed that it killed human brain cells that had been growing in lab dishes too. prM is the mutated protein that is part of the amino acid that the virus tells to make. This mutation helps the virus take hold in the cell. It also helps it leave too. Shi is still confused as to why this mutation causes such drastic abnormality because even before it killed brain cells, just not to this extent. Another scientist Scott Weaver of the University of Texas Medical Center, thinks that researchers should spend more time figuring out how the Zika virus and its mutations work.