State governments in the region tried to respond quickly, and in November 2015, the Brazilian government declared a national health emergency as cases of microcephaly increased.By February 2016, the World Health Organization had declared a global public health emergency in response to the spread of Zika.
Raquel, 25, holds her daughter Heloisa in Areia, Paraíba state, Brazil.
She collected samples of amniotic fluid from both patients and sent them to Fundação Oswaldo Cruz (Fiocruz), a scientific institution in Rio de Janeiro, for analysis.
Both samples tested positive for the Zika virus, establishing the first concrete link between microcephaly and the mosquito-borne illness.
The outbreak hit as the country faced its worst economic recession in decades, forcing authorities to make difficult decisions about allocating resources in response.
Dengue has been present in Brazil for decades, so when hundreds of thousands of people with cases of what was thought to be a milder case of dengue began arriving in health clinics in late 2014, it was worrying but not a surprise—until the wave of children born with microcephaly.