The U.S. declared the Zika virus outbreak in Puerto Rico a public health emergency on Friday, which U.S. Health and Human Services says means the virus is a “significant threat” to the territory. The declaration comes amid massive spread of Zika through Puerto Rico, infecting well over 6,000 people, including over 520 pregnant women.
In the continental U.S., local mosquitoes in Florida are still spreading the virus. So far there are 25 cases of Zika spread to people from mosquitoes in the area. Still, some polls suggest, like a recent Washington Post-ABC News one, that Americans are not incredibly concerned about the virus.“I’m sorry that people feel that way, but it is a problem,” U.S. Centers for Disease Control and Prevention (CDC) director Dr. Tom Frieden said in a recent press conference. “The tragedy of a preventable case of a severe birth defect is something I think we have to make very clear to people.”
Here’s why the virus is of concern.
It takes time before Zika’s effects are seen
Although scientists are still trying to answer basic questions about the virus, it appears that the most at risk time for a pregnant woman to become infected is early in pregnancy. The amount of time between initial infections and the possible births of infants with microcephaly can be several months, which some health officials speculate could be the reason there’s less sense of urgency among the public. “The problem appears a little theoretical because it’s largely asymptomatic and largely in the future,” Frieden told TIME in a recent interview. “We will have babies born with microcephaly.”