Microcephaly caused by or associated with congenital infections in the last 20 years in Brazil: a systematic review

This systematic review aimed to identify the pathogens causing or associated with congenital microcephaly in Brazil in the last 20 years due to the lack of official information by the Health Authorities and, as a consequence the uncertainty on the real infectious etiology of congenital microcephaly. A review protocol was prepared according to the PRISMA recommendation, using the PubMed, SciELO and LILACS databases to search for references presenting original data on microcephaly caused by or associated with congenital infectious in Brazil, using the descriptors "MICROCEPHALY AND INFECTION". The search ended on 30/Jun/2020. All selected titles were read in full and analyzed independently by the three reviewers. After searching the databases, 2,389 articles were selected for title review. Of these, 109 were excluded due to duplicates and 2,236 according to the criteria defined in the review. Only 44 met the eligibility criteria and were therefore read in full. Data extraction was performed on 10 articles, all published after 2015. Seven studies were literature reviews or case series, only two were case-control, and one was a cross-sectional study. As the studies focused on the period of the ZIKV epidemic in Brazil, the cases of congenital microcephaly between 2015 and 2017 were attributed to maternal infection by this virus when it was not possible to prove the presence of other etiological agents. Among the TORCH agents, a predominance of syphilis was observed. The analyzed studies did not add consistent information about the infectious causes or association of microcephaly in Brazil outside the period of ZIKV epidemic, revealing the need for more studies on the subject.