"Whether Zika virus has shifted or drifted in its antigenic properties, we really don't know with the current outbreak that's going on. There's something that's caused it to be much more widespread, whether it's increased mosquito numbers, environmental factors that may influence more mosquitoes being infected with it or more mosquitoes in an area"said Steven M. Presley, professor, The Institute of Environmental and Human Health at Texas Tech University.

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