Novel human astroviruses: challenges for developing countries

Abstract

Astroviruses have been gaining widespread importance over the past few decades owing to their detection through advanced molecular techniques. The association of astrovirus-associated enteric infections have been reported from various settings among different age groups. The tremendous efforts of scientists from different countries to detect and characterize these star-like viruses in the course of surveillance has shown the emergence of novel astroviruses from varied host species, necessitating changes in the classification to update their taxonomy. The public health importance of these viruses implies new control measures are essential to reduce disease burden in developing countries.

Human astroviruses: in silico analysis of the untranslated region and putative binding sites of cellular proteins

“…2b). The phylogenetic analysis carried out with 3′ UTR sequences showed that classical and novel astrovirus are divergent, in which the clade VA1-VA5 and AST/PS for example, is less related with the classical astrovirus than the MLB1-3 clade as previously reported [2,3]. The biological significance of sequence conservation between classical and non-classical astrovirus, particularly the GGG TAC AGCG motif shared in classical and clade VA1-VA5 and AST/PS, remains to be uncovered, although it could be speculated that it might be involved in global replication process.…”

“…This high degree of sequence conservation among the different classical and novel astrovirus serotypes supports the possible involvement of this region in important viral functions. The sequence similarities in both virus types may result of recombination events between human and animal strains, as previously suggested [2,3], suggesting that they share similar mechanisms such UTRs-proteins interaction-mediated replication. From our analysis above and considering the proposal that 5′ and 3′ UTR might be required elements for viral replication and RNA synthesis [27], we set to establish whether the 5′ UTR of the HAstV region could be structurally conserved.…”

“…It has been suggested that the UTRs of several RNA viruses, such as dengue, human calicivirus, norovirus, West Nile, enterovirus, Hepatitis C virus and others, are involved in the translation and replication [16,19,21,27,69]. To explore a possible link between the sequence conservation and functional significance in classical HAstV, we carried out multiple sequence alignments of the 5′ UTRs of all the classical HAstVs and novel astrovirus (known as non-classical astrovirus) sequences available in the GenBank [2,3]. The analysis revealed that the 5′ UTR contains several conserved motifs identical among all HAstV serotypes and novel astroviruses.…”

“…Human astroviruses (HAstVs) are a major cause of acute gastroenteritis in children, the elderly and in immunocompromised subjects [1], therefore constituting an important problem public health. Recently, new members of the Astroviridae family have been associated with neurologic disorders in humans, and several reports have suggested the possibility of a cross-species transmission that could eventually become a zoonotic problem [2,3].…”

Astrovirus evolution and emergence

“…2). Since 2008 and the advent of pan-astrovirus degenerate primers (Chu et al, 2008) and sequence based phylogenetics, astroviruses have been classified by their ORF2 full length amino acid sequence into three species of AAstV and 19 species of MAstV (Bosch et al, 2012;Donato and Vijaykrishna, 2017;Krishnan, 2014). Until 2008, human astrovirus infections were thought to be caused by 8 genotypes of closely related viruses known as HAstV 1-8 (De Benedictis et al, 2011).…”