This year in Brazil at least 2,400 babies were born with suspected microcephaly -- a rare condition that causes shrunken skulls and often severely damaged brains. This number is much higher than usual: In 2014, the country had just 147 cases of microcephaly.
Scientists believe the increase in babies being born with the condition may be the result of a mosquito-borne virus called Zika, which they also believe might have begun affecting more people in recent years due to the effects of climate change.
The situation is so dire that six Brazilian states have declared a state of emergency, and health officials are encouraging women to to hold off on becoming pregnant, CNN reports.
"These are newborns who will require special attention their entire lives. It's an emotional stress that just can't be imagined," Angela Rocha, a pediatric infectologist in Brazil, told CNN. "We're talking about a generation of babies that's going to be affected."
Microcephalic brain, left; typical brain, right
According to a report from the Washington Post, Zika was first discovered in monkeys in the Amazon over 70 years ago. Infections in humans were extremely rare until just a few years ago, when, "for reasons scientists can't explain but think may have to do with the complicated effects of climate change, it began to pop up in far-flung parts of the world."
According to NPR, experts are citing climate change in part because a "harsh drought has been affecting Brazil, so people are storing water on their rooftops. The Aedes aegypti [mosquito] loves to breed in standing water in urban environment."
The Zika virus was first documented in humans in 2007 on Yap Island, Tahiti. It arrived in Brazil in May of this year and now "tens of thousands have fallen ill," according to the Washington Post. In adults the virus causes a mild fever, rashes, vomiting, joint aches and headaches, but is rarely deadly -- so discovering that many of the mothers of infants born with microcephaly were infected with Zika has caused alarm among health officials.
Brazil is sending thousands of teams of health care workers out to treat people's homes and other places where the Aedes aegypti could breed in an attempt to eradicate the mosquitoes and slow the spread of the virus. According to CNN, "In Rio de Janeiro, the host city for the 2016 Olympics, officials said they have already made more than 9 million house visits to eradicate the stagnant pools used as a breeding ground for mosquitoes."
Health officials are also warning Brazilians -- especially pregnant women -- to stay inside when possible and wear plenty of bug spray if they have to go out.
The Washington Post notes that in the United States, Zika has been found in a few travelers returning from affected regions, but the CDC has "not come across any cases of people being infected by mosquitoes in the country."