The World Health Organization today declared the spread of the Zika virus to be an international public health emergency, less than a week after officials confirmed the first case of the virus in the United States, in Los Angeles County, in a young girl who had recently traveled to El Salvador who has since recovered. While no person-to-person transmissions have been reported in the U.S., according to the CDC, there have now been a few coming from travelers who recently came from affected countries — we know of one in Arkansas, one in Virginia, and five in New York state.

The New York Times reports that the virus has spread to 20 countries throughout the Americas, and warns of a feared link between the virus and birth defects in babies.

According to a W.H.O. fact sheet, Zika "symptoms are similar to other arbovirus infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache. These symptoms are usually mild and last for 2-7 days."

Unfortunately, at present there is "no specific treatment or vaccine currently available," notes the fact sheet.

If you're healthy and not pregnant, you should just get better on your own. Officials worry, however, about the impacts of the virus on developing fetuses. It is yet to be proven that a Zika infection increases the liklihood of having a child born with microcephaly, a condition which leads to smaller heads and brain damage in babies, but a spike in the birth defect has correlated to the increase in infections.

The concern is real enough that officials in El Salvador are warning women not to get pregnant until 2018, notes the Times.

Which, if that's not insane enough to get your attention, the seriousness of this entire situation becomes immediately clear with the knowledge that the W.H.O. has only declared three public health emergencies in its history — this is the fourth. The other three were the result of the Ebola virus, polio, and the swine flu, notes Quartz. (It should be noted, however, that the W.H.O. has only started issuing these warnings in the last ten years.)

The virus is spread by mosquitoes, and public health officials encourage those in areas with the virus to use mosquito repellent, and to wear clothing that covers skin.

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