Giselle Ribeiro, 27, plays the saxophone during a “bloco,” a street party, in downtown Rio de Janeiro. (Lianne Milton/Panos Pictures for The Washington Post)

For the next few nights, Tuane Rocha, a tall, radiant samba queen, will be dancing naked in the streets of this city, wearing only body paint.

Mind you, she will take precautions. “First I’m going to put on a layer of repellent,” she said. “Then makeup. Then the paint.”

Rocha dances fast — really fast. She figures she can keep the mosquitoes at bay if she keeps moving.

Because nothing stops Carnival in this country. Not the government, nor a lousy economy, nor the Zika pandemic.

Millions of Brazilians will be in the streets this coming week for one of the world’s biggest bacchanals, a dancing and drinking binge that draws revelers from all over the world. No doubt some of them will go home with Zika and spread it even more. Huge crowds at Carnival celebrations across the Americas will give the virus new opportunities to propagate — by mosquito but also potentially through sexual contact.

From left: Fernanda Morais, 22, Tuane Rocha, 35, and Thais Avella, 31, discuss an upcoming Carnival routine during a meeting at a samba school in Rio de Janeiro. (Lianne Milton/Panos Pictures for The Washington Post)

The arrival of Carnival points to one of the inherent challenges in fighting the Zika outbreak. The World Health Organization has declared the outbreak a “global emergency.” But it doesn’t quite feel like one. At least not here, despite the terrifying possibility that it is bringing into the world a wave of babies born with small heads.

Pregnant women and their families are petrified. But unlike Ebola, cholera or AIDS at its advent, the Zika virus doesn’t present an immediate, lethal threat to the broader population. As many as 80 percent of those infected have no symptoms. And the best — really the only — way to fight it is for people to do something that they should have been doing anyway: eliminating the mosquito breeding pools in their homes and yards.

The mosquitoes that carry Zika flourish, too, in places that belong to no one. Rio de Janeiro’s spectacular urban rain forests and lush mountainsides teem with them. So do the city’s vacant lots and roadsides, strewn with garbage where water collects. Carnival, which began Friday, will probably bring even more trash.

Just as authorities here have bristled at calls to cancel the Summer Olympics scheduled for August, there was never any question in Brazilian minds that Carnival would go on despite Zika. Canceling it would be similar to the U.S. government trying to cancel Christmas. It is the country’s most sacred holiday, said Brazilian sociologist and columnist Luiz Simas. Its very purpose is to help people forget about their problems.

“People abroad might find this a little strange,” he said. “But in the history of Rio, at the most difficult moments, Carnival is even more intense.”

“You don’t party at Carnival because life is good,” Simas said. “You party at Carnival because life is difficult.”

In addition to its main parade, a massive, corporate-sponsored procession with thousands of dancers gyrating in elaborate costumes, Carnival also consists of hundreds of neighborhood-level street parties known as “blocos,” where the drumming and drinking last long into the hot nights of the Southern Hemisphere’s summer. It’s hard to think of a better place for mosquitoes and for promiscuity.

Images of Carnival revelry here may contribute to international perceptions that Brazil isn’t doing enough to contain the outbreak or sound alarms, for fear of losing much-needed tourism revenue for Carnival and the Olympics.

Revelers at a bloco in Rio’s Centro neighborhood. (Lianne Milton/Panos Pictures for The Washington Post)

Fernanda Franca, 33, dances at a street party. (Lianne Milton/Panos Pictures for The Washington Post)

This week, the country’s Health Ministry also fired back at complaints from scientists and researchers in the United States and Europe who say they are unable to properly study Zika because Brazil isn’t sharing enough test samples.

Authorities reject claims that they aren’t taking the pandemic seriously or should cancel the Summer Games. President Dilma Rousseff has urged Brazilians to mobilize against the virus, and she promised expectant mothers that the government “will do everything, absolutely everything in our power to protect you.”

In a speech this past week, Rousseff declared “war” on Aedes aegypti, the mosquito that is the primary vector for the virus. She has ordered more than 220,000 soldiers to fan out across the country to hand out leaflets at 3 million homes. About 50,000 will hunt for pools of standing water where the insects breed.

But not until next week. After Carnival.

“People here expect the government to do a lot for them,” said Leandro do Nascimiento, a city health worker passing out brochures and condoms ahead of Carnival. “We need them to take responsibility for this, too.”

He joined a large group of health and sanitation workers dancing to samba music and passing out condoms and lubricant packets near commuter trains this week. They do the event every year ahead of the festivities to encourage HIV prevention, but this year, they added Zika materials, and a few dressed up in mosquito costumes, wearing plastic wings and rubbery proboscises.

Several residents said these were the first government workers they had seen talking to people about the virus. “We don’t know much about Zika. Only what we’ve heard on television,” said Alessandro Tavares, speaking at Rio’s Central Station, alongside his wife, Vanessa Dos Santos, who is nine months pregnant. Anti-mosquito brigades that are supposedly fanning out across the city with larvicide have yet to show up in their neighborhood, he said.

“The city and the state government don’t even have the money to keep the public hospitals open, but they still want to have the Olympic Games,” said Tavares, who, like many Brazilians, expresses little faith in the ability of the country’s recession-hobbled government to confront the crisis.

The couple live high up on a hillside in one of the city’s favelas, where mosquitoes thrive. They keep their doors and windows closed, slather on bug repellent every day, and Dos Santos has not had Zika symptoms. But they worry about the baby they are expecting.

“It’s in God’s hands now,” Tavares said.

Carnival costume pieces at a samba school in Rio’s Madureira neighborhood. (Lianne Milton/Panos Pictures for The Washington Post)
A surge in cases

Brazil is investigating a possible Zika connection to more than 3,000 reported cases of babies born with underdeveloped heads and brains, the condition known as microcephaly.

The highest number of cases have been reported in northern Brazil’s Pernambuco state. Now, more cases are appearing in Rio, said Alexandra Araujo, a pediatric neurologist at the federal university hospital here. “I have never seen so many in such a short time,” said Araujo, who has been working at the hospital since 1983.

So far, Brazil is the only country in the Americas where authorities have seen a surge of infants born with microcephaly, and Araujo acknowledged that a direct link between Zika and the birth defect has not been proved. But she has seen “too much of a jump” in recent weeks, she said.

There are currently about 3,000 pregnant women in Rio state — which has a population of 16 million — who have reported Zika symptoms, she said. There were 171 newborns diagnosed with microcephaly statewide last month, after 66 in all of 2015.

One of them was Luiz Felipe, born Dec. 28. His mother, Pollyana Rebello, 27, was diagnosed with Zika during her eighth month of pregnancy. For her, it is not a time for Carnival celebrations.

“Only with time will we know if he will improve,” Rebello said, cradling the boy in her suburban home on the outskirts of Niteroi, a town near Rio. “It could be that he’s able to talk but not walk.”

To her, Luiz Felipe is a normal boy, she said. “He just has a little head.”

But she said others in the community have stigmatized the family. “People think that microcephaly is a contagious disease, and it’s not.”

Her cousin Stephani Moura, 24, who is four months pregnant, sat on the couch and fawned over Luiz Felipe. She said that she was trying to protect herself as best she could against mosquitoes.“I have the fan on all day, the windows closed, and I put repellent on every two hours,” Moura said. “And I wear long pants.”

But not that day. In Rio’s stifling humidity, she was wearing shorts and a vest. “In this heat, no one can stand it,” she said.

Read more:

Brazil may have fewer Zika-related microcephaly cases than previously reported

What is Zika? And what are the risks as it spreads?

CDC: To avoid Zika exposure, consider no sex

Today’s coverage from Post correspondents around the world