Zika is a mosquito-borne virus. It causes mild symptoms of fever, rash, joint pain and eye redness. About one in five people who are infected actually become sick.
How do you treat it?
There is no medication for the illness, and it typically clears up with rest and fluids within a week.
Is it fatal?
No, but it may pose a risk to pregnant women’s fetuses. The virus has been linked to microcephaly, a condition in which babies have small heads and incomplete brain development; Brazil saw a spike in rates of the condition in 2015. While officials investigate whether there is a link to the country’s Zika infections, they have recommended Brazilian women delay getting pregnant if possible. However, the CDC says more information is needed to conclusively determine a link. “Since there are many causes of microcephaly in babies, it will take some time to determine the cause of these cases,” said a spokeswoman in an emailed statement to TIME.
Should we be worried?
Maybe. A case in Puerto Rico was confirmed in December; the patient had not recently traveled, which means the virus was acquired from a local mosquito. Another case was confirmed in Houston in January, in someone who had recently traveled to an undisclosed country. (The CDC says similar imported cases have occurred before.)
For that person to infect others, he or she would have to be bitten by a mosquito during the “relatively short” time the virus is present in his or her blood, and that mosquito would then have to bite another person. “With the recent outbreaks in the Americas,” the CDC says, “the number of Zika virus disease cases among travelers visiting or returning to the United States will likely increase.” This will be more likely to pose a problem in warmer areas of the U.S. during the winter, as mosquitoes die off in freezing conditions.
What should pregnant women do?
Pregnant women traveling to affected areas should take several precautions, like “using insect repellent; wearing long-sleeved shirts and long pants; and staying in places with air conditioning or with window and door screens to keep mosquitoes outside,” the CDC says. “Using an insect repellent is safe for all people, including pregnant and breastfeeding mothers.”