Jusikelly da Silva was full of expectations for her baby. This was to be her fourth with her spouse, Josenildo, and the couple had three other children from previous relationships. “All perfect, all normal,” her husband said of their family.

Then, at the six-month mark of her pregnancy, Jusikelly, 32, learned from a scan that her baby had microcephaly, a rare defect that causes infants to have unusually small heads and can lead to learning and motor difficulties.

Parents such as the da Silvas are struggling as South America’s largest country faces an unprecedented outbreak of microcephaly cases. Brazilian officials say the disease is being triggered by Zika — a little-known virus borne by mosquitoes. The government has spent more than $300 million to battle the mosquito, mobilizing hundreds of soldiers in the effort.

Concern about Zika has grown so strong that the U.S. Centers for Disease Control and Prevention late Friday issued a travel alert urging pregnant women not to visit Brazil or about a dozen other countries in the region where mosquitoes have spread the virus.

In the northeastern city of Recife, Jusikelly wiped away tears as she cuddled and kissed her baby Luhandra, now two months old. “She will have some mental difficulties,” she said. “She does not react like other children. She does not laugh.”

The da Silvas’ lives are on hold, the mother said.

“We stopped everything,” said Jusikelly. After the diagnosis, the couple dropped plans to open a small bakery. “I couldn’t work,” she said.

The rise in microcephaly cases in Brazil has been startling: there were just 147 in 2014. But since October, 3,530 possible cases of Zika-related microcephaly have been reported to the Ministry of Health. Authorities say the real number of cases is almost certainly lower, with some of those misdiagnosed as microcephaly. Still, officials have also reported 46 deaths of babies who had microcephaly that may have been related to Zika.

A new link

The Zika virus was first identified in a rhesus monkey in Uganda in 1947, but its initial outbreak in humans was in 2007, on the South Pacific island of Yap. It is typically transmitted to people by infected mosquitoes and can cause flulike symptoms.

But the virus had never been linked to microcephaly before. Instead, microcephaly was thought to be genetic or caused by diseases such as rubella. Researchers say they are now in unchartered territory on the issue.

“The disease in Brazil is behaving in a different way,” said Camila Ventura, an ophthalmologist at Recife’s Altino Ventura Foundation who has found eye damage in babies with microcephaly — another first. “We are running against time.”

Nadja Bezerra, 42, with her two-month old baby, Alice Vitoria, who was born with suspected Zika-related microcephaly, visits her neighbor in Recife, Brazil, on Jan. 10. (Lianne Milton/Panos Pictures for The Washington Post)

Brazilian authorities first confirmed the presence of the Zika virus in May. Some researchers speculate it may have been introduced into the country by a tourist attending the 2014 World Cup. It has now spread to other countries in Latin America, and Puerto Rico recorded its first case in December. A Texas woman who traveled to El Salvador has also been diagnosed with the virus.

The World Health Organization and the CDC have yet to definitively establish a connection between Zika and microcephaly, which has been reported only in Brazil. But the CDC, which is helping to investigate the Brazilian outbreak, has just provided the strongest sign yet of such a link — confirming the presence of Zika in the bodies of two newborns who died and in the placentas of two women who miscarried. All four cases also involved microcephaly.

The Brazilian Health Ministry says 80 percent of those who catch Zika show no symptoms. The rest may suffer fever, muscle pain and rashes for a few days. Most people who come down with it recovery quickly.

“We never paid too much attention to this virus,” said Paulo Zanotto, a microbiology professor at the University of Sao Paulo who is coordinating a network of 42 laboratories studying Zika. “I’m really worried because we have no idea of the amount of spread.” The government estimates that there are between 400,000 and 1.4 million Zika cases in the country.

Brazilian authorities have launched a national plan in response to the outbreak, sending over 100 tons of a biological agent that kills mosquito larvae to affected areas. It has set up headquarters in affected states, staffing them with military, health and education officials.

‘Love, care and patience’

In Recife, mothers impacted by the outbreak are struggling to come to terms with their babies’ conditions.

On a recent morning, Mariana Carvalho, 16, cuddled her six-week-old daughter, Agatha, after a consultation at the local Oswaldo Cruz hospital. Agatha was diagnosed with microcephaly a day before she was born.

“At the time I didn’t believe it. I wanted my daughter to be normal,” she said. But Carvalho said she loves her daughter nonetheless. “It doesn’t change anything,” she said.

Maria Rodrigues, 29, suffered Zika-like symptoms while she was pregnant with Maria Eduarda, her ninth child. When the baby was born on Nov. 22, she was diagnosed with microcephaly.

Rodrigues and the infant’s father, Romero Perreira, 39, scratch out a living recycling garbage they collect on the streets. Romero’s sister Miriam, 40, plans to adopt Maria Eduarda.

Doctors told Miriam the infant could face problems walking, talking and hearing — she already struggles to swallow and see properly. “The only thing we can give her is love, care and patience,” the aunt said, cradling the child in her house in a Recife suburb, next door to the tiny dwelling where the baby’s parents live.

The microcephaly cases have occurred around the country, but the most significant concentrations are in northeastern states such as Pernambuco. The Zika virus may have spread especially quickly there because residents have stored water in tanks during a long-running drought, creating breeding grounds for mosquitoes, said José Iran, health secretary for Pernambuco.

Some doctors in northeastern Brazil have gone so far as to advise women to hold off getting pregnant.

The Brazilian army has provided 750 soldiers to fight the mosquito in Pernambuco. On a recent Saturday morning in Recife, the state’s capital, troops joined health workers going door to door in the Brasilia Teimosa neighborhood to warn residents against leaving water receptacles uncovered. They also spooned a powdered biological agent into tanks and drains in an attempt to kill any mosquito larvae.

Many residents said that either they or relatives had caught Zika or other mosquito-borne diseases such as dengue or chikungunya.

“I would describe this as one of the biggest challenges in public health in Brazil’s recent history,” said Jailson Correa, Recife’s health secretary, referring to the outbreak of those diseases and the microcephaly cases.

In Recife, the rate of new microcephaly cases has diminished in recent weeks, but there are fears of another outbreak if Zika spreads during the summer.

Parents affected by the outbreak are preparing themselves for a difficult future with children who may need constant care.

Nadja Bezerra already had a 15-year-old son when she found herself pregnant last year. Then a scan at seven months revealed that her baby’s head and brain had not grown as they should have.

“The bomb dropped,” she said. “The worst day of my life.”

The 42-year-old cried as she recalled how, after her daughter, Alice, was born two months ago, she lay in the maternity ward and watched other mothers pass by with healthy babies.

Bezerra has decided to give up her job at a call center to care for Alice. The family will depend on the $173 monthly salary that her husband, João, 54, earns cleaning planes at the nearby airport.

“I am very scared,” she said.

Lena H. Sun in Washington contributed to this report.

Read more

Brazil’s new hero is a nerdy judge who is tough on official corruption

In the Amazon, the ‘world’s most endangered tribe’ has few options

A cheating public employee is caught in the act, and Brazil can’t stop watching