The designation, only used three times before, indicates the severity of the situation.
The World Health Organization has declared the recent outbreak of the zika virus in South America an international public health emergency after a committee meeting Monday. The virus, long thought to be a fairly innocuous infection, has recently been linked to a rise in babies born with microcephaly, a deformity that prevents the brain from fully developing.
Though a conclusive link tying the virus to microcephaly has not yet been established, there's mounting evidence that the two are connected and the concern is now great enough that the WHO decided to invoke the emergency status, only the fourth time it has ever made such a declaration.
"I don't think people are concerned about raising a false alarm. People are concerned about getting to the bottom of what's causing microcephaly," Dr. Bruce Aylward, the WHO's Executive Director ad interim of the Outbreaks and Health Emergencies Cluster, said during a press conference on the decision. "This is definitely the right measure to be taking at this time based on the information available."
Spread by the Aedes aegypti mosquito—the same species that spreads other dangerous viruses like dengue and chikungunya—Zika was first discovered in the 1940s but was never closely monitored or studied. This is partly because the disease was never widespread—the virus was mostly confined to tropical Africa, Southeast Asia, and the Pacific Islands until last spring when it appeared in Brazil—and partly because it was never associated with any serious symptoms. Many people infected with zika don't have symptoms, and those who do suffer only mild aches and fever.
But five months after the virus first appeared in Brazil, reports began streaming in of an increase in microcephalic births. Along with the time correlation, researchers found the virus in newborns with microcephaly. It's still too early to confirm with certainty what the link is between the virus and the deformity, and what risk it may pose to developing fetuses, but the surge in microcephalic births coupled with the alarming rate at which the virus is spreading—it's now been contracted in 14 countries and territories—has many panicked. There's no vaccine or treatment for zika, though multiple research projects have already begun in a race to find a solution.
Other ideas, like sending out genetically-modified mosquitoes to wipe out the Aedes aegypti, are being floated as countries take emergency measures, including advising travel bans for pregnant women and even advising women to avoid getting pregnant until we have a better grasp on the situation at hand.
The good news is that the WHO declaration will help draw more attention to the outbreak, and gives governments tools to devote more funding to research and mitigation efforts. Many critics wagered the ebola outbreak in west Africa could have been less deadly if the WHO had declared it an international public health emergency sooner. The speedy response from the WHO this time around indicates just how serious the current outbreak is.