Characterisation of a G2P[4] Rotavirus Outbreak in Western Australia, Predominantly Impacting Aboriginal Children

Area of Science:

• * Virology
• * Epidemiology
• * Public Health

Background:

• * An outbreak of rotavirus gastroenteritis occurred in May 2017, primarily affecting Aboriginal children under 4 years in Western Australia's Kimberley region.
• * The dominant circulating genotype was identified as G2P[4], with most samples showing a conserved electropherotype via polyacrylamide gel electrophoresis.

Purpose of the Study:

• * To characterize the full genome of the rotavirus strain responsible for the 2017 outbreak.
• * To analyze the phylogenetic relationship of the outbreak strain to other G2P[4] strains.
• * To assess the implications of the findings for the Australian rotavirus vaccination program.

Main Methods:

• * Full genome sequencing of representative rotavirus samples.
• * Phylogenetic analysis of all gene segments.
• * Comparison of the outbreak strain's G2 component with the RotaTeq vaccine.

Main Results:

• * The outbreak strain exhibited an archetypal DS-1-like genome constellation (G2-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2).
• * Phylogenetic analysis indicated close relatedness to contemporary Japanese G2P[4] strains and Australian/Hungarian strains from 2010, but not to strains from previous Northern Territory outbreaks.
• * Mutations were observed in antigenic regions of the G2 component compared to the RotaTeq vaccine, but these are common in contemporary G2P[4] strains.

Conclusions:

• * The 2017 rotavirus outbreak in the Kimberley region was caused by a G2P[4] strain closely related to contemporary international and past Australian strains.
• * Rotavirus outbreaks continue to occur in vaccinated populations, posing challenges, especially in remote areas.
• * Continuous surveillance and characterization of emerging rotavirus variants are crucial for the success of Australia's vaccination program.