In the heated pool, ten-year-old Stephany Vitória Silva Costa is weightless. The water soothes her convulsing muscles, providing brief respite from constant pain, and she coos with delight, igniting smiles among everyone in the room.

Stephany is a “Zika baby”; one of more than 3,080 children born with Congenital Zika Syndrome (CZS) following a devastating outbreak of the mosquito borne virus that swept Brazil in 2015-16. At least 444 of those children have died, mainly from respiratory and infectious diseases.

Like most of the surviving children from the cohort, she has suffered from an array of symptoms including microcephaly, severe cognitive and motor impairment, vision and hearing loss and seizures – which can occur up to ten times a day.

But a decade after the outbreak, a second wave of complications are emerging in children like Stephany.

As her therapist gently turns her in the pool, a pronounced bulge shows through the back of her pink and blue swim top. Over the last two years, her growing spine has been pulled 120-degrees into an S-shaped curve that is now crushing her lungs.

While many of the children born with microcephaly after the outbreak died in early infancy, a much-loved group including Stephany lived on. Now, however, mortality rates are again climbing as the children near adolescence.

“It weighs heavily on my heart. After so many years of following these children, it is inevitable to form bonds – not only with them, but with their families,” says Dr Milena Cavalcanti, one of just 11 paediatric neurologists in the state.

“Every loss affects me deeply. It is very hard to say goodbye to them”.

At the Altino Ventura Foundation’s (FAV) hydrotherapy centre, steam clings to murals depicting ocean scenes – a smiling pink octopus swims around a silver painted shipwreck.

As Stephany coos, another girl in a brown swimsuit and rainbow coloured shorts smiles as her mother fills a cup with water and pours it over her black curls.

Originally an ophthalmology institute, FAV expanded into neuro-rehabilitation as the Zika crisis unfolded. It provides free therapy to children with CZS twice a week, with treatment plans reassessed every six months.

Some 230 children affected by the syndrome have had therapy at the foundation and 84 are currently being treated. Its clinicians are tracking the cohort’s long-term development.

None of the Zika children present can walk or hold themselves up, and the majority have already had at least one major surgery.

Nevertheless, Gustav Wagner, a physiotherapist, says installing the hydrotherapy pool – which increases blood flow and loosens muscles – was a major breakthrough.

The children can’t express pain verbally. Mr Wagner and his team instead use a visual scale from one to ten, based on reading their posture and expressions. The mothers, above all, learn to spot the smallest changes and the pool, they say, makes a huge difference.

“It’s a very peculiar disease,” says Amanda Rodrigues, a physiotherapist. “We have to learn with them how to get better – we have never treated something like this before”.

First discovered in 1947 in Uganda’s Zika forest, the Zika virus is thought to have quietly reached Brazil in 2014.

Experts attribute its arrival to increased air travel; either carried by visitors landing for the 2014 FIFA World Cup or brought from active outbreaks in the South Pacific islands.

Either way, the virus spread unnoticed and unchecked in Brazil for over a year.

Most Zika infections are asymptomatic or easily mistaken for dengue, both cause a similar red rash and flu-like symptoms.

The alarm was finally raised in August 2015 when neuropaediatrician Dr Vanessa van der Linden identified an unprecedented surge in infants born with microcephaly across Pernambuco state.

“It was very chaotic at the beginning,” says Dr Milena Cavalcanti. She added that doctors frantically coordinated emergency responses over WhatsApp as the crisis unfolded.

“The physical toll on the children was devastating,” she said.

Infections early in pregnancy inflicted the worst damage. And in one of the side rooms of the hydrotherapy centre, it’s evident that the disabilities are profound.

Five children sit motionless in their wheelchairs with blankets pulled up to their necks. One of them, Emily Sophia dos Santos Luna, weighed just six kilograms at age two before being given a feeding tube to enable her to survive.

The children are unable to swallow, causing mucus to pool in the back of their throats. To prevent choking, their wheelchairs are permanently tilted at a 45 degree angle.

“In the beginning, we thought they would discover a treatment,” says Emily’s grandmother, Maria José da Silva, 43. “But now we understand she will always be this way”.

She added: “It’s a very difficult life, but God gave us the power to keep going. I will take care of her until the day God wants”.

In the therapeutic gym, a large room filled with foam mats, standing frames and slings hung from the ceiling, Allana Kauane perches on a large silver balance ball.

She wears a green skirt, shin-high pink socks, and a white T-shirt that has “be happy” printed in shimmery lettering.

Ms Rodrigues, her physiotherapist, supports her torso and bounces her gently to build core strength. With every movement, she patiently lifts Allana’s head back up as it falls onto her chest.

Thailene Maria, the child’s 28-year-old mother, waves a bright gold pompom in front of her eyes in an effort to draw her focus.

Down the corridor in a consultation room, Dr Cavalcanti examines another patient.

It’s a girl who has not had a seizure in six years, but her last one lasted thirty minutes – six times the length that defines a medical emergency in Brazil.

Manuelle does not like to be touched, her grandmother says. She used to bite herself, now she pulls at her own hair instead.

As Dr Cavalcanti taps gently at her knee with a reflex hammer, the girl tenses and struggles to lie flat. Fine dark hair has started to grow along the girl’s shins – a side effect, says Dr Cavalcanti, of the anticonvulsant medication she relies on to control her seizures.

It is one of several changes the clinic still cannot fully explain. Many patients entered puberty years earlier than expected, one as young as three. Most are treated with hormone-blocking injections.

“We don’t know,” says Dr Cavalcanti, when asked about the cause. “We are just following the cases”.

On the ground floor, past the therapy rooms, sits the Capela Santissima Trinidade, a small wood-pannelled chapel. Inside, there are rows of pews, and in the centre is a large stained glass window.

It’s a small reminder that the building was designed to cater for the spiritual needs of its patients alongside their medical care.

While infants with CZS initially received only basic motor stimulation, severe musculoskeletal issues are emerging as they reach adolescence.

Dr Epitácio Rolim, the top orthopaedic surgeon in the state, has tracked a cohort of 152 children since the outbreak.

By age 10, 98 per cent developed orthopaedic deformities – 70 per cent suffer hip deformities, and 64 per cent from spinal curvature.

Previously, the public health system did not offer corrective surgeries or have a structured waiting list.

Dr Zilda Cavalcanti, Health Secretary of Pernambuco state, told The Telegraph: “We know we have a lot to do yet. The needs are giant and the funds are not”.

The root problem is neurological, says Dr Rolim. Damaged brain pathways create severe muscle imbalances around major joints. Unable to reposition themselves, the children’s relentless muscle tightness pulls their hips out of their socket and twists their spines.

Delaying intervention drastically restricts surgical options, Dr Rolim warns.

In the worst cases, repairing the hip is no longer possible. Surgeons must instead remove the top of the thigh bone simply to stop it from grinding against the socket.

“I am not talking about surgery to make most of these children walk,” says Dr Rolim. “The realistic goal is quality of life… hope does not mean promising a cure that we do not have… it means living with as little pain as possible”.

Only five to seven per cent of pregnant women exposed to Zika had babies with visible symptoms like microcephaly. For the rest, timing of the infection in pregnancy determined how destructive the virus was.

“The children you saw with microcephaly were at the extreme end of the spectrum,” says Dr Ernesto Marques, a senior researcher at Fiocruz in Recife. “As the others become teens, developmental delays are showing up more clearly”.

Dr Patricia Garcez, a neuroscientist at King’s College London who helped establish the link between Zika and brain defects in 2016, said that many of the “milder” CZS cases are now displaying severe autism and neurodevelopmental delay, or motor deficits caused by prenatal Zika exposure without severe microcephaly.

The night we arrive in Recife, known as the “Brazilian Venice”, heavy rains transform the city’s roads into rivers. Gesturing to the rising water outside, our taxi driver chuckles: “Here we say: When someone sneezes, the whole city floods”.

Centuries ago, the city was a low-lying landscape of tidal sandbanks, estuaries and mangroves. When Dutch colonisers arrived in the 1600s, they engineered canals, bridges and dikes to prevent flooding and make the swamplands habitable.

It is this geography that made Recife, the capital of Pernambuco, the epicentre of the 2015-16 Zika outbreak, its pools of still water proving the perfect breeding ground for mosquitoes.

The state recorded around 742 confirmed CZS cases – 24 per cent of cases nationwide, and 39 per cent of cases in the northeast.

In Recife’s hillside favelas – densely populated, self-built communities largely lacking basic public services – residents were forced to store tap water in open buckets and barrels due to intermittent water flow making the mosquito problem worse.

Halfway up a steep hill in Favela do Monte, Joane da Silva Sena lives in deep poverty, caring alone for her 10-year-son, Heytor, who was born with microcephaly in November 2015.

Ms Sena, 36, a thin, weary-looking woman with a kind face, is entirely on her own.

The father abandoned them at birth, and the neighbours refuse to even watch Heytor while she goes to the shop, instead watching her struggle up the hill from their homes.

“My family doesn’t help me, nobody cares,” she says. “People are afraid of Heytor, they say he’s ‘special’.”

Inside the house, only secured with metal bars on gaping door and window frames, Ms Sena frequently skips meals so Heytor can eat. There’s a shadow on the wall of the pink-painted kitchen where the fridge should be. She had to throw it out because it kept giving her electric shocks and was too expensive to repair.

Heytor’s specialised wheelchair broke months ago, leaving him only with an ill-fitting wicker chair that he constantly slumps on.

Ms Sena lifts his 54 kg frame roughly 10 times a day between the chair and the bed to soothe him when he gets agitated. She also carries him up the steep hill twice a week to reach physiotherapy classes.

“I will not abandon him,” Ms Sena says through tears. “I just ask God for health, because if I get sick, no one will look after him”.

In August 2025, Brazil’s Congress passed a bill – first floated in 2015 – to compensate the families of children born with microcephaly and other disabilities caused by Zika.

The package includes a one-off payment of 50,000 BRL (£7,150), and a tax-free monthly support payment of 8,150 BRL (£1,165), five times the previous allowance.

But despite the national law, Ms Sena receives very little support.

The hospital Heytor was born in did not provide official documentation linking Heytor’s condition to Zika, even though multiple experts say that it is the cause.

Ms Sena said she dreams about having access to the funds, adding that she would love to “buy a beautiful armchair that will be so comfortable for him”.

After The Telegraph raised her case with the Pernambuco Health Department, state officials launched an investigation into Heytor’s birth records and admitted him to the hospital for a complete evaluation.

They also dropped off medication and nappies at the house and have arranged for a vehicle to transport them to therapy classes.

Acknowledging that Ms Sena’s struggles span housing, transportation, social support and caregiver mental health, the state told The Telegraph it would assemble a multi-agency task force to assist her.

Across Brazil, the mothers of children with Zika are renowned for their resilience.

Many were young and living in poverty when the outbreak hit. Fuelled by deep rooted stigma, most were then abandoned by their partners after their children were born with disabilities.

It took a decade of campaigning for these women – a movement known as the Mothers of Angels – to finally secure the social security breakthrough last year.

They proved that the state failed families twice over: by not containing the virus, and by under-compensating the children for years.

It remains unclear whether Brazil is vulnerable to another Zika outbreak.

In 2016, amid the original epidemic, the World Health Organization declared a public health emergency of international concern.

A few months later, cases began to drop and today the population is thought to be protected by herd immunity.

However, that immunity is unlikely to last forever.

A study in Salvador, the capital of nearby Bahia state, found antibody protection dropped from 59 per cent to under 39 per cent within two years of the first outbreak.

Dr Marques estimates Brazil could see another outbreak resulting in children born with CZS within 15 to 20 years.

A new generation has grown up without having been exposed to the virus, creating a growing population vulnerable to infection, he says.

The root cause of poor water infrastructure and mosquito infestation also hasn’t been resolved.

“Almost everybody born after 2016 has not been exposed to Zika at all… they are naive, and that piles up with the older people who did not get infected,” he told The Telegraph.

“Once the population vulnerable to Zika reaches a critical threshold, the risk of another outbreak grows”.

The research that could prepare Brazil for that eventuality has stalled.

There is still no approved Zika vaccine or antibody treatment. The most advanced candidate has only just completed early-stage safety trials, and experts say a larger trial is nearly impossible without an active outbreak to test it.

Basic diagnostic tools also have major limitations. Standard antibody tests still cannot reliably distinguish Zika from dengue, and PCR testing – the only definitive testing method – is only effective for around five days at the peak of infections.

For Erika Silva Costa and her ten-year-old daughter Stephany, the child with severe scoliosis, the struggle to secure that necessary care has reached a standstill.

Ms Costa contracted Zika five months into her pregnancy. When doctors recommended that she terminate, she refused.

A former MRI technician, Ms Costa is now a full-time caregiver and a prominent campaigner for Zika children.

“My dedication to her is total, 24 hours a day… my brain is always awake,” she says, adding that she sleeps in the same bed facing Stephany in case she chokes during the night. “I feel like the umbilical cord was never cut”.

Despite the urgent need, Stephany’s position remains perilous.

Her doctors say she needs an operation costing 150,000 BRL (£21,400) on her spine but so far she has been refused coverage by medical insurers. Ms Costa is now mounting a legal battle to fight the decision in court.

“The authorities together with the health services aren’t tackling this properly,” said Dr Rolim.

“It’s so frustrating. The professionals know what needs to be done, but can’t do it because the system doesn’t provide the right conditions”.

With the public health system crippled by long waiting lists and a lack of specialised equipment, families like Ms Costa are waiting in limbo.

“Sometimes one of the children dies and we all fall apart,” she says. “We have to believe in God to wake up the next day and be strong”.

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