An overview of Zika virus genotypes and their infectivity

Abstract

Zika virus (ZIKV) is an enveloped, single-stranded RNA arbovirus belonging to the genus Flavivirus. It was first isolated from a sentinel monkey in Uganda in 1947. More recently, ZIKV has undergone rapid geographic expansion and has been responsible for outbreaks in Southeast Asia, the Pacific Islands, and America. In this review, we have highlighted the influence of viral genetic variants on ZIKV pathogenesis. Two major ZIKV genotypes (African and Asian) have been identified. The Asian genotype is subdivided into Southwest Asia, Pacific Island, and American strains, and is responsible for most outbreaks. Non-synonymous mutations in ZIKV proteins C, prM, E, NS1, NS2A, NS2B, NS3, and NS4B were found to have a higher prevalence and association with virulent strains of the Asian genotype. Consequently, the Asian genotype appears to have acquired higher cellular permissiveness, tissue persistence, and viral tropism in human neural cells. Therefore, mutations in specific coding regions of the Asian genotype may enhance ZIKV infectivity. Considering that mutations in the genomes of emerging viruses may lead to new virulent variants in humans, there is a potential for the re-emergence of new ZIKV cases in the future.

FIGURE 1:. ZIKV polyprotein from the African- and Asian-ZIKV genotypes, structural proteins (C, prM, and E) and nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) as well as their sizes, in amino acids (aa), and functions in the viral cycle.

FIGURE 2:. Permissiveness and replication cycle of the ZIKV genotypes in host cell.