Zika virus (ZIKV) is an emerging pathogen member of the Flaviviridae family. ZIKV has spread rapidly in the Latin American region, causing hundreds of thousands of cases of ZIKV disease, as well as microcephaly in congenital infections. Detailed studies on the pattern of evolution of ZIKV strains have been extremely important to our understanding of viral survival, fitness, and evasion of the host’s immune system. For these reasons, we performed a comprehensive phylogenetic analysis of ZIKV strains recently isolated in the Americas. The results of these studies revealed evidence of diversification of ZIKV strains circulating in the Latin American region into at least five different genetic clusters. This diversification was also reflected in the different trends in dinucleotide bias and codon usage variation. Amino acid substitutions were found in E and prM proteins of the ZIKV strains isolated in this region, revealing the presence of novel genetic variants circulating in Latin America.

Zika virus (ZIKV) is a member of the family Flaviviridae . In 2015, ZIKV triggered a large epidemic in Brazil and spread across Latin America. In November of that year, the Brazilian Ministry of Health reported a 20-fold increase in cases of neonatal microcephaly, which corresponds geographically and temporally to the ZIKV outbreak. ZIKV was isolated from the brain tissue of a fetus diagnosed with microcephaly, and recent studies in mice models revealed that ZIKV infection may cause brain defects by influencing brain cell developments. Unfortunately, the mechanisms by which ZIKV alters neurophysiological development remain unknown. MicroRNAs (miRNAs) are small noncoding RNAs that regulate post-transcriptional gene expression by translational repression. In order to gain insight into the possible role of ZIKV-mediated miRNA signaling dysfunction in brain-tissue development, we computationally predicted new miRNAs encoded by the ZIKV genome and their effective hybridization with transcripts from human genes previously shown to be involved in microcephalia. The results of these studies suggest a possible role of these miRNAs on the expression of human genes associated with this disease. Besides, a new ZIKV miRNA was predicted in the 3’stem loop (3’ SL) of the 3’untranslated region (3’UTR) of the ZIKV genome, suggesting the role of the 3’UTR of flaviviruses as a source of miRNAs.