Brazil's Ministry of Health made an unprecedented announcement this month: It told women in the northeast of the country not to get pregnant for the foreseeable future.
And it's all because of a mosquito — the Aedes aegypti species, which can spread a variety of diseases, including Zika virus. Health experts in Brazil are concerned that the virus, whose symptoms are typically a low-grade fever and bright red rash, might be having a devastating impact on newborns.
In the past few months, doctors have been seeing a rise in microcephaly, a rare neurological disorder that results in infants having small heads and underdeveloped brains, causing severe developmental issues. Children born with this illness are likelier to die young and require constant care.
On Oct. 20 Dr. Kleber Luz, an infection specialist at the Federal University of Rio Grande do Norte in the city of Natal, got a call from a colleague in another northern city with a question: How many cases of microcephaly had been diagnosed recently?
"Normally in a year you'd have maybe three or four cases," he says by phone from his home city of Natal in Brazil's north. "In 24 hours when we asked around, there had been 11 in the city. And that was a shocking enough number that we realized something very serious was happening."
Luz and his team asked around and discovered that most of the mothers diagnosed with microcephalic fetuses had something in common: They had Zika virus early in their pregnancy.
Zika virus was first discovered in the 1940s in Uganda and named after a forest there.
It's not clear when Zika arrived in Brazil, though some doctors speculate it could have come with African visitors during the World Cup.
Initially, it wasn't a concern. Normally, Zika is not a serious infection, unlike malaria and dengue, for example. People are ill for a few days and generally recover.
But after the cases of microcephaly popped up, Luz remembered a paper that had been written in 1971, showing that rats infected with Zika developed a neurological condition.
Brazil's Ministry of Health says there is now a suspected link between Zika and the cases of microcephaly in infants.
"Everyone involved in this is extremely concerned about what could happen," says Luz. "We don't yet understand this illness."
The Health Ministry is now working with the Centers for Disease Control and Prevention and an arm of the World Health Organization to figure out what is going on. In the meantime, six states in Brazil have announced a state of emergency. There are 1,761 cases of microcephaly; many more are expected as Brazil's Health Ministry says more than 1 million people could have contracted the virus.
Luz also says women in the northeast should refrain from getting pregnant, echoing the recommendation of the ministry.
In the meantime, the government is sending out teams of health inspectors to try to control the mosquito that spreads the disease.
In a middle-class neighborhood in the north of Rio de Janeiro, health inspectors went door to door this week looking for places where the Aedes aegypti mosquito breeds. They looked into cisterns and empty plant pots, taking water samples.
At one house 36-year-old owner Elisabete de Abreu said her father-in-law has the virus, so she knows this is important.
"It's an enormous concern because of the children," she said.
The Aedes aegypti bloodsucker spreads not only Zika but yellow fever, chikungunya and dengue. It first arrived in Brazil on slave ships coming from Africa; in the mid-20th century it was almost wiped out after a huge outbreak of yellow fever led to a concerted eradication campaign.
But experts say the mosquito came back after those measures were relaxed. These days it's everywhere. Beyond Zika, Brazil is actually suffering a dengue epidemic right now as well, with over 1.5 million cases in the country.
One of the reasons is climate change, according to experts. A harsh drought has been affecting Brazil, so people are storing water on their rooftops.The Aedes aegypti loves to breed in standing water in urban environments. The female needs to feed on blood to mature her eggs, and cities have both a lot of people and places to lay eggs.
But it's not clear why Zika virus could be having this effect on fetuses.
"It's a mystery for everyone. We only just started looking into this a month ago," says Denise Valle, a researcher and entomologist at Fundacao Oswaldo Cruz, a leading scientific research center in Rio de Janeiro, who studies the Aedes aegypti.
Dr. Angela Rocha is an infection specialist with the Oswaldo Cruz Hospital in the state of Pernambuco, where many of the microcephaly cases have been detected.
"I've been an infection specialist for more than 40 years and I've never been through such a period of stress. If we don't get a handle on this, we are going to have a generation of damaged babies," she warns.
It could take years to determine whether the mosquito is to blame. The ban, meanwhile, is a suggestion. But many women are in a state of high alert — and some pregnant women are living in a fog of citronella.
Valdemar Geo contributed to this story.
KELLY MCEVERS, HOST:
Now to a medical mystery in Brazil. There's a little-known virus that's spreading through the Americas. It's called the Zika virus, and because of it, Brazil's health ministry made an unprecedented announcement this month. It told women in certain parts of the country not to get pregnant. The worry is that the virus is causing a spike in birth defects. NPR's Lourdes Garcia-Navarro reports from Rio de Janeiro.
LOURDES GARCIA-NAVARRO, BYLINE: It was October 20, and Dr. Kleber Luz, an infectologist at the Federal University of Rio Grande do Norte in the city of Natal, got a call from a colleague in another northern city with a question - how many cases of microcephaly had they diagnosed recently, he was asked. Microcephaly is a rare neurological disorder that results in infants being born with small heads and severe developmental issues because of underdeveloped brains.
KLEBER LUZ: (Speaking Portuguese).
GARCIA-NAVARRO: "Normally, in a year," he tells me, "you'd have maybe three or four cases. In 24 hours, when we asked around, there had been 11 in the city. And that was a shocking enough number," he says, "that we realized something very serious was happening."
But what? Most of the women were then discovered to have had the Zika virus early in their pregnancy. Dr. Luz remembered a paper that had been written back in 1971 showing that rats infected with Zika developed a neurological condition so an emergency meeting was convened where it was discovered that cases of microcephaly had exploded in many parts of the country.
LUZ: (Speaking Portuguese).
GARCIA-NAVARRO: He tells me, "this is a situation without precedent. Everyone involved in this is extremely concerned about what could happen. We don't yet understand this illness," he says. Zika virus was first discovered in the 1940s in Uganda and it was named after a forest there. The symptoms are flu-like - low grade fever, a rash. It's carried, like dengue, by a specific type of mosquito - more about that in a minute. Zika arrived in Brazil sometime last year. It's not clear when, but doctors weren't initially worried. Normally it's not that serious an infection, unlike malaria and dengue. They are very worried now, though.
LUZ: (Speaking Portuguese).
GARCIA-NAVARRO: News programs are giving the virus blanket coverage. Meanwhile, Brazil's health ministry is working with the CDC and an arm of the WHO to confirm the link between Zika and microcephaly. Six states in Brazil have announced a state of emergency. There are 1,761 cases of microcephaly with the suspected cause being Zika so far. Brazil's health ministry says more than a million people could have contracted Zika already so Dr. Luz says women should refrain from getting pregnant for now, echoing Brazil's recommendation.
In the meantime, the government is sending out teams of health inspectors to try and control the mosquito spreading the disease.
So we're climbing up onto the roof to see the standing tanks of water which people use.
ALFONSO JUNIOR: (Speaking Portuguese).
GARCIA-NAVARRO: This inspector, Alfonso Junior, tells us he's taking a water sample from the cistern to see if there are any mosquito larvae. The mosquito they are hunting for is the Aedes aegypti. This bloodsucker spreads not only Zika but yellow fever and dengue. It first arrived in Brazil on the slave ships coming from Africa and it was almost eradicated in the mid-20th century here. But these days it's everywhere, and one of the reasons is climate change. There's been a harsh drought affecting Brazil which causes people to store water. The Aedes aegypti loves to breed in standing water.
ELISABETE DE ABREU: (Speaking Portuguese).
GARCIA-NAVARRO: Thirty-six-year-old house owner Elisabete de Abreu says her father-in-law has the Zika virus so she knows inspections like this are important. But it's a race against time. Dr. Angela Rocha, an infection specialist with over 40 years of experience who is dealing with the crisis, had this warning.
ANGELA ROCHA: (Speaking Portuguese).
GARCIA-NAVARRO: "I've never been through such a period of stress," she told us. "If we don't get a handle on this, we could have a generation of damaged babies." Lourdes Garcia-Navarro, NPR News, Rio de Janeiro. Transcript provided by NPR, Copyright NPR.