Researcher of Gonçalo Moniz Institute (IGM/Fiocruz Bahia) Guilherme de Sousa Ribeiro coordinated a clinical and epidemiological study using intracranial imaging exams to rule in or rule out the occurrence of any congenital brain abnormalities in children with suspected microcephaly potentially related to zika virus infection in Salvador, Bahia. The research was conducted in collaboration with the Center for Strategic Information on Health Surveillance (Cievs), of the Municipal Secretariat of Health of Salvador, and published in the scientific journal Eurosurveillance, under the title Congenital brain abnormalities during a Zika virus epidemic in Salvador, Brazil, April 2015 to July 2016.
In the paper, the authors describe clinical and epidemiological aspects of the outbreak of microcephaly occurring in Salvador and evaluate the performance of different screening criteria which use the baby’s head circumference at birth to detect children with suspected microcephaly. Such evaluation was conducted by correlating the results of circumference measurements with the findings in imaging exams. According to the research, in the period from April 2015 to July 2016, 650 babies born in Salvador were reported for suspected microcephaly, of which 365 had their medical records reviewed for obtaining intracranial imaging exam results.
Among the 365 cases investigated, 166 (45.5%) presented some abnormality in imaging exams, while 199 (54.5%) had normal results. The most common lesions identified by the exams were brain calcifications (86.1%) and dilation of the ventricles (86.1%). The period of greater detection of children with abnormalities in imaging examinations was December 2015, when for every 100 live births, two children were affected. It was also observed that when compared to children with normal imaging exams, those with abnormalities in imaging exams were significantly more likely to having been born prematurely and to mothers who presented clinical manifestations suggestive of zika virus infection during pregnancy.
Finally, the research highlights that none of the screening criteria for the detection of microcephaly by the head circumference at birth presented satisfactory performance, indicating that other screening strategies are required. Therefore, the authors conclude suggesting that the effective detection of children with risk of presenting congenital Zika syndrome should combine the conduction of intracranial imaging exams, such as pre and postnatal ultrasound, and the clinical history during pregnancy, especially the presence of symptoms compatible with zika virus infection.