In a remote farmhouse in northeast Brazil, Miriam Araujo rises in darkness at 3 a.m. to set off on a three-hour journey to get treatment for her son at the country's first center for microcephaly.

The physiotherapy is vital for the five-month-old infant, born with an abnormally small head, brain damage and motor control issues. Doctors believe that Lucas - like hundreds of other children - developed microcephaly due to the Zika virus his mother contracted when she was pregnant.

A wiry 25-year-old with sharp eyes, Araujo makes the arduous 280-km (175-mile) round-trip up to three times a week to the clinic in Campina Grande, the second city of Paraiba, one of Brazil's poorest states.

Hard-hit by three years of drought that wrecked corn crops, her family's only means of transport is an old motorbike. Authorities in Sao Jose dos Cordeiros send a battered Fiat to take her the 9 km of rough dirt track into town, where she catches a minibus for the distant clinic.

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Her family's plight shows how unprepared Brazil's creaking public health service was for Zika when the mosquito-borne virus struck last year.

The distance and difficulty of organizing transport meant that for his first months, Lucas did not receive the regular massages, stretching and visual stimulation needed to aid his mental development. Experts say that could set him back for life.

"I wish I could go more often," Araujo says as insects swarm a bare bulb hanging from a beam of the one-storey home. "I'm afraid they'll stop sending the car. Then what will we do?"

While Zika has spread most rapidly in the urban squalor of northeastern coastal cities like Recife, Araujo is one of a growing number of women giving birth to children with microcephaly in the Sertao, an isolated semi-arid region in the interior.

Here, mosquitoes thrive in the open sewage and stored water of poor communities, where the taps often run dry.

At the hospital in Campina Grande, a bustling city of 350,000 people, medical staff are treating 29 babies for microcephaly. All but six come from the surrounding region and must travel long distances because there is no treatment closer to home.

The center occupies three small rooms in a corner of the hospital. The physiotherapy room has a bright green mat and luminous exercise balls on which the babies have their muscles stretched. Their vision is stimulated with black and white patterns.

"There is talk of opening centers in other towns so mothers don't have to travel so far, but I don't see it happening," said the city's health secretary, Luzia Pinto.

Last year, Brazil cut healthcare spending by 17 percent and more savings are planned in 2016 as the government tries to shore up public finances amid the deepest recession in decades. Pinto said Zika is causing the worst crisis she has seen in 28 years of working in public health.

TREATMENT ABSOLUTELY VITAL

Much remains unknown about Zika. The virus was detected in Brazil in 2015 and has since spread to over 20 countries in the Americas, leading the World Health Organisation to declare a global emergency. The biggest impact so far has been in Brazil, especially among the poor.

Scientists have yet to prove Zika causes microcephaly, although Brazil has confirmed more than 500 cases in the last few months and believes most of them are related to Zika. Authorities are investigating another 3,900 suspected cases.

The condition was so rare before - an estimated 150 cases a year in a country of 200 million people - that there had been little call for treating it.

The center in Campina Grande - which employs a neurologist, physiotherapist, psychologist and otolaryngologist - costs about 45,000 reais ($11,000) per month to run.

Pinto said that could double in the next two months as more babies with microcephaly arrive for treatment. Scientists say the cases in Brazil are unusually severe.

"We're seeing very grave neurological issues in many of these babies and the right stimulation therapy is absolutely vital to give them a chance of developing key functions like walking and talking," said Dr Alba Batista, the center's neurologist.

Campina Grande is asking the health ministry for 6 million reais over the next 12 months. Part of the funds will be used to buy vital equipment like a Magnetic Resonance Imaging (MRI) scanner, which the local public health system does not have.

Brazilian Health Minister Marcelo Castro told Reuters this month that funds would be available to fight Zika and care for disabled children, despite deep cuts to the health budget.

World Health Organization data shows Brazil's government spends $523 per capita on health care, less than Chile or Cuba and nearly 8 times less than the United States.

Free healthcare is meant to be universal in Brazil, although those who can afford to do so - around a quarter of the population - go private instead.

Pinto does not believe federal money will arrive soon. "I think we'll get an MRI machine from organizations that have offered to help us in the U.S. before we get one from our own government."

RIO EMERGENCY

Paraiba is not the only state where cracks in the health system are appearing.

In Rio de Janeiro, which hosts the Olympic Games in August, patients complain of a lack of medicines and long queues as Zika worsens an existing crisis in the health sector.

A dramatic fall in oil royalties being paid to the state government as the price of crude crashed left it struggling to pay salaries and equipment. The governor announced a state of emergency at the end of last year as hospitals ran out of funds and were forced to close some units.

Rio has two confirmed, and 227 suspected, cases of microcephaly but a spike in Zika infection rates means doctors expect more in the coming months.

"If today it's already difficult to attend to the population of Rio, what will happen during the Olympics with the arrival of millions of people to watch the Games?" said Jorge Dazre, president of Rio's Doctors Union.

Meanwhile, more babies with microcephaly are being born in Paraiba.

At her home in the small town of Congo, 29-year-old Adilma de Oliveira said she tried to get pregnant for nearly 10 years.

Her joy turned to pain when her baby, due next month, was diagnosed with microcephaly.

"I'm scared of the future," said Oliveira, her bright smile fading. "I don't even want to think about it."