The human aspect of the Zika outbreak

In Ibura, a poor neighborhood in Brazil's northeastern city Recife, Gleyse Kelly cradles her fourth child, Giovanna, who is just three months old.

"My biggest fear was that she wouldn't be able to walk, wouldn't be able to talk," Gleyse said, breastfeeding Giovanna, sitting on the couch in her humble one-story house that her father built.

Baby Giovanna has microcephaly, a condition where babies are born with smaller-than-average heads and suffer varying degrees of brain damage, usually causing development problems and often severe learning difficulties, sometimes even death. Gleyse found out about seven months into her pregnancy.

"I hope that she will be able go on and study. She is just like any other child, just with a smaller head," she said, pointing out that the only difference between Giovanna and her other three children when they were at the same age is that her newborn doesn't respond well to being bottle fed.

While Gleyse is optimistic about her daughter's future, experts say it's very likely that baby Giovanna will require full time care for the rest of her life, putting enormous pressure on a mother who earns just $250 (230 euros) a month working as a toll booth attendant and receives $25 in government child benefits. Her husband is currently unemployed.

The World Health Organization has declared a state of emergency over the mosquito-borne Zika virus, which they say is linked - though this is still unproven - to thousands of cases of microcephaly across Brazil. More than 4,000 suspected cases of microcephaly have been recorded since the beginning of 2015. In 2014, there were just 150 cases.

Brazil's poorer northeastern states have seen the overwhelming majority of cases of Zika infections. Recife, in the state of Pernambuco, has recorded about a third of the suspected cases and is at the center of the epidemic.

The main theory for the origin of the crisis is that Zika was brought by visiting tourists during Brazil's 2014 World Cup.

Brazil's president, Dilma Rousseff, said that around 220 thousand soldiers will mobilize on February 13 to eradicate mosquitoes and advise local populations how to avoid the virus.

A vaccine will take several years to develop, experts say, so in the meantime the best way to avoid the virus is to limit conditions where mosquitoes breed, such as stale water supplies in homes.

However, in poorer neighborhoods like Ibura, where Gleyse lives, housing is often informal, trash collection sporadic, and education poor among local populations - creating a perfect storm for airborne viruses such as Zika.

Angela Rocha, of the Oswaldo Cruz hospital in Recife, where the signs of the outbreak were first recorded, says that the poor socioeconomic conditions in Recife provide the ideal breeding ground for the virus.

"It's an affliction that thrives on poverty," she said.

In Coqueiro, another poor neighborhood in Recife, health workers give out leaflets to residents and advise them how to avoid mosquito-borne viruses.

Soldiers who have been called in to assist health workers eliminate possible Zika larvae, formed in rainwater collected in a tire that a local resident left outside his house.

When questioned why he left the tire outside during the rainy season, the resident replied, "I forgot."

At one house, a middle-aged woman says that everyone in her family has suffered from dengue fever, also transmitted by mosquitoes. Health workers advise her that the paddling pool in her back yard will breed larvae if not emptied soon.

Authorities in Recife say that Brazil's current economic recession is causing more obstacles for containing the virus and that requests for emergency funding from the federal government have not been met.

Jalison Correria, secretary of public health for the city of Recife, says that 29 billion Brazilian reals (6.7 billions euros) had initially been asked for - at this point, only R$1.3 billion has been received.

"The Zika virus is very serious. This is the biggest public health threat we are facing in recent history," he said.

Activists have called for Brazil's Supreme Court to loosen its extremely restrictive abortion laws - permitted only in the case of rape - for women pregnant with microcephaly affected babies, which has caused a backlash on social media. Even Gleyse Kelly, mother of microcephaly-affected baby Giovanna, is an active participant, posting anti-abortion messages.

The World Health Organization has advised against pregnant women travelling to Brazil and for women living in Zika-affected areas to seek professional advice.

Authorities have downplayed suggestions that the virus will have a huge negative impact on tourism as Brazil prepares for its annual carnival and later this year to host the Olympics and Paralympics. However, they do concede that there will be an inevitable knock on effect.

Back at Gleyse's house, her mother, husband and three sons sit in the living room. Gleyse answers messages on her cell phone while cradling Giovanna. She smiles.

"My biggest fear of all was that she would die after I gave birth," she said.