By Sarah Ferris - 02/01/16 01:44 PM EST
Top health officials at the United Nations have officially declared the spread of the Zika virus a global health emergency, with as many as 4 million cases expected in the next year.
While the virus causes mild symptoms resembling dengue fever in healthy adults, it can be dangerous for pregnant women and has been linked to birth defects. The virus could also be linked to a rare paralyzing condition called Guillain-Barré syndrome, though a correlation is unconfirmed.
Last week, officials warned that the virus is spreading “explosively,” with millions of cases expected in the next few months. Many more cases are expected to occur in the U.S., which has reported about a dozen so far.
The Centers for Disease Control and Prevention (CDC) said last week that a major Zika virus outbreak is unlikely in the U.S., though the Obama administration has pledged to step up education and research efforts.
Dr. Margaret Chan, director of the WHO, has said she is “extremely alarmed” by the quick spread of the virus.
Thousands of cases have been reported across South and Central America.
In Brazil, which is considered the epicenter of the current outbreak, authorities have recorded hundreds of birth defects they believe are linked to the virus.