Progress in knowledge on the relationship between Zika virus infection during pregnancy and severe congenital neurological disorder (thus far referred to by its principal sign, microcephaly) has been so rapid, serious, and consistent that it is sure to make health history. The story began in August-September 2015, when obstetricians and neonatologists in Pernambuco State, Brazil, observed an increase in the number of congenital malformations, followed by an alert issued by the Pernambuco State

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... ealth Department and the Ministry of Health in October, launching an investigation into the problem. By November 11 there was already sufficient evidence for Brazil to declare a Public Health Emergency of National Concern. On February 1st, 2016, the World Health Organization declared a Public Health Emergency of International Concern (PHEIC), basing its decision on the same criteria as the Brazilian declaration 1 . The virus already existed and circulated in various countries of Africa and Asia, so why was this excessive number of microcephaly cases only reported in Brazil? First, although the frequency of fetal malformations is high among women with a history of Zika virus infection early in pregnancy, the hardest-hit countries at the onset of the epidemic, especially the island nations of Micronesia and Polynesia, have small populations, and malformations there are rare. Retrospectively, however, the virus was detected in some cases of fetal malformations that occurred in those countries during the 2013 outbreak 2 . But Brazilian Unified National Health System (SUS) has also played an essential role, since it provides most of the childbirth care in the country, especially among the poorest population. This broad-reaching health system revealed the bigger picture and raised epidemiological suspicion. Brazil also has serious and high-quality research, capable of combining epidemiological investigation and health care, without losing sight of the patient's central importance. A recent event organized by the team at the epicenter of this "earthquake" in Recife (Pernambuco), called the Workshop on the A, B, C, D, and E of the Zika Virus (http:// scf.cpqam.fiocruz.br/eventozika/), discussed what is being done in research, from virology to serology, from clinical practice to epidemiology. And much is being done. From the onset of the outbreak, the Editorial Board of CSP decided that articles dealing with any aspect of Zika would follow a "fast track" review. This edition of our journal features three articles addressing different questions. The paper Microcephaly in Pernambuco State, Brazil: Epidemiological Characteristics and Evaluation of the Diagnostic Accuracy of Cutoff Points for Reporting Suspected Cases discusses the technical grounds for redefining the cutoff point for suspected cases of microcephaly. In the midst of accusations in the gutter press and internet that data were being manipulated to hide the epidemic, the authors present the scientific basis for the protocol adopted by the Brazilian Ministry of Health to define suspected cases. Starting with the submission through the peer review and reformulation, the article was approved in just 28 days.