What caused the Zika virus, which had lain low since its discovery in the forests of Uganda in the 1940s, to trigger such severe outbreaks in recent times?
A group of researchers say a gene mutation detected after 2012 could have enhanced the virus' power to overcome immunity in the Aedes mosquito, its main carrier, and increase its power to infect.
The Asian lineage of the virus, responsible for the recent epidemics, underwent mutation, increasing its potency to infect, according to the research published in Nature Communications journal Monday.
The research found the evolutionary mutation can increase the ability of Zika to overcome the host mosquito's immune response, reproduce more efficiently and cause greater infection and epidemics, Shi Peiyong, a virologist at the University of Texas Medical Branch at Galveston and leader of the research team, said.
Zika, spread mostly by the bite of an infected Aedes mosquito, can be passed on by a pregnant woman to her fetus.