The Evolution of Post-Vaccine G8P[4] Group a Rotavirus Strains in Rwanda; Notable Variance at the Neutralization...

Area of Science:

• Virology
• Genetics
• Epidemiology

Background:

• Africa exhibits significant genetic diversity in rotavirus strains, potentially explaining reduced rotavirus vaccine effectiveness.
• The G8P[4] strain is a notable contributor to this rotavirus diversity within the African region.

Purpose of the Study:

• To fully elucidate the genome and evolutionary history of G8P[4] rotavirus strains identified in Rwanda.
• To investigate potential genetic factors contributing to vaccine evasion in African rotavirus strains.

Main Methods:

• Whole-genome sequencing using Illumina technology was performed on twenty-one Rwandan G8P[4] rotavirus strains.
• Phylogenetic analysis was employed to determine the evolutionary relationships of the sequenced strains with known human and animal rotavirus strains.

Main Results:

• Twenty of the twenty-one Rwandan G8P[4] strains possessed a DS-1-like genotype constellation, with one exhibiting a reassortant genotype.
• Significant amino acid differences were found at neutralization sites compared to vaccine strains, indicating potential neutralization escape.
• Phylogenetic analysis linked five genome segments to East African human rotavirus strains, two NSP4 segments to bovine strains, and VP1/VP3 sequences to the RotaTeq™ vaccine WC3 bovine genes.

Conclusions:

• The evolution of Rwandan G8P[4] rotavirus strains, particularly VP1 and VP3 segments, may involve reassortment with bovine genes from the RotaTeq™ vaccine.
• Close phylogenetic ties with G8P[4] strains in Kenya and Uganda suggest co-circulation across East Africa.
• Continuous whole-genomic surveillance is essential for understanding G8P[4] strain evolution, especially post-rotavirus vaccine introduction.