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Published on: August 1, 2013
Lineage diversification and recombination in type-4 human astroviruses
Vito Martella1, Maria C Medici, Valentina Terio
1Dipartimento di Medicina Veterinaria, Università Aldo Moro di Bari, Valenzano, Italy.
Summary
Human astroviruses (HAstVs) are common enteric pathogens. A novel lineage, HAstV-4c, characterized by conserved ORF1b/ORF2 genes, now dominates global type-4 strains, highlighting recombination
Area of Science:
- Virology
- Molecular Biology
- Public Health
Background:
- Human astroviruses (HAstVs) are significant enteric pathogens, genetically classified into eight types.
- Surveillance in Italy revealed sporadic type-4 HAstVs clustering into two genetic groups.
Purpose of the Study:
- To characterize novel type-4 HAstV strains detected in Italy.
- To investigate the genetic lineage and evolutionary history of type-4 HAstVs, including potential recombination events.
Main Methods:
- Sequence analysis of the 3' end of the polymerase gene (ORF1b) and the full-length ORF2.
- Database interrogation to assess the global prevalence of identified lineages.
- Comparative analysis of genetic markers to identify potential recombination.
Main Results:
- A novel ORF2 genetic lineage, designated 4c, was identified in 2008 type-4 HAstV strains.
- This lineage 4c, with a conserved ORF1b/ORF2 asset, constitutes 60.8% of worldwide type-4 strains and dominates recent detections.
- Older type-4 HAstVs (2002) showed a type-4b ORF2 but resembled type-1 HAstVs in ORF1b, suggesting recombinant origins.
Conclusions:
- Recombination likely drove the diversification of type-4 HAstV ORF2.
- The emergence and global spread of the HAstV-4c lineage underscore the importance of ongoing molecular surveillance.
- Multi-target analysis is crucial for accurate characterization and identification of recombinant HAstVs.
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