Researchers from the University of California, Davis, and the Lawrence Livermore National Laboratory (LLNL) have discovered that outbreaks of human disease may be due to genetic mutations and that viruses may change as they expand their geographic range.
The researchers studied how the Zika virus mutated over space and time during the 2015 outbreak. The virus was first identified in 1947 and has since transformed from a mild virus to one capable of sexual transmission and microcephaly, a neonatal brain malformation.
The virus contains an RNA genome that mutates rapidly, which allows the virus to adapt to diverse hosts.
Researchers used deep sequencing to detect genome mutations, and many variants were found in multiple samples.
The researchers’ models indicate that the majority of mutations associated with epidemic transmission occur on the exposed surface of viral proteins.
“Understanding which combinations of mutations spread widely and become established in new geographic regions versus those that disappear relatively quickly is essential for defining the trajectory of an ongoing epidemic,” Nicole Collette, LLNL biologist and co-author of the study, said.
Data from the study was organized into an interactive database that allows researchers to study the spread of individual mutations and combinations of them.