A once-rare mosquito-borne virus called Zika is spreading rapidly through the Americas since arriving in Brazil last May, with a case confirmed in Texas this week in a traveler returning from Latin America. Health officials are alarmed because of a possible link between the virus and a birth defect called microcephaly, which causes babies to be born with abnormally small heads and potential developmental problems.

Health officials are worried that the Zika outbreak in Brazil may be linked to a dramatic increase in babies being born with unusually small heads. Brazil usually records only about five to six cases of microcephaly for every 100,000 live births. As of the end of November, the rate was 20 times that: nearly 100 cases for every 100,000 births, according to the World Health Organization.

Health authorities haven’t definitely confirmed that Zika is behind the spike in kids being born with abnormally small heads. But they don’t have another explanation for the spike in microcephaly. “The question is, is this a new phenomena?” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

http://www.bloomberg.com/news/articles/2016-01-15/the-zika-virus-is-coming-to-the-u-s-here-s-what-you-need-to-know