E-Poster with pre-recorded video presentation Lorne Infection and Immunity 2021

Genetic characterisation of zoonotic rotavirus strains identified in children and adults with acute rotavirus gastroenteritis in Australia  (#303)

Celeste M Donato 1 2 3 , Elena Demosthenous 1 3 , Susie Roczo-Farkas 1 , Rhian Bonnici 1 , Sarah Thomas 1 , Paloma Moreno 1 , Carl D Kirkwood 1 2 4 , Julie E Bines 1 2 5
  1. Enteric Diseases, Murdoch Children's Research Institute, Parkville, Victoria, Australia
  2. Department of Paediatrics, University of Melbourne, Parkville, Victoria , Australia
  3. Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
  4. Enteric and Diarrheal Diseases, Global Health , Bill & Melinda Gates Foundation, Seattle, Washington, USA
  5. Department of Gastroenterology and Clinical Nutrition, Royal Children’s Hospital, Parkville, Victoria, Australia

 

Background

Rotavirus strains are classified into G and P genotypes based on the two outer capsid proteins. To date, 36 G types and 51 P types have been characterised from humans and animal species. Whole genome sequencing allows for the classification of all 11 rotavirus genes to describe genome constellations and reassortment events. Rotavirus is capable of infecting human and animal hosts, and zoonotic transmission occurs. Zoonotic transmissions have the potential to result in highly competitive viruses that circulate widely in the human population; antigenically distinct to human strains. The Australian Rotavirus Surveillance Program conducts an ongoing investigation of the rotavirus strains causing disease in Australia. The aim of this project was to investigate the genetic diversity and origins of unusual rotavirus strains.

 

Methods

Unusual rotavirus strains were selected between 2009 to 2019, from adult and paediatric patients with acute gastroenteritis. Following random amplification of viral RNA, whole genome sequencing was performed on an Illumina MiSeq platform. Sequence assemblies were performed using Geneious Prime. Maximum likelihood and Bayesian phylogenetic analysis was performed.

 

Results

In this study, G3P[3], G3P[8] and G3P[9] samples were identified as canine/feline-like and were derived via independent reassortment events between human and animal strains. These strains were detected over a number of years in multiple regions highlighting sustained human-to-human transmission. Several strains with bovine origins were detected including G6P[14], G8P[14], G10P[14], G8P[1], G8P[4]  and G10P[25]. These strains exhibited a highly conserved genome constellation. This suggests a highly conserved bovine-like strain has undergone several independent reassortment events and been introduced into the human population multiple times with widespread human-to-human transmission.  A number of strains also had genes that may have been derived from viruses circulating in bats, camels and other animal species.

 

Conclusions

This study highlights the diversity of rotavirus strains circulating in Australia and the wide potential for zoonotic transmission. The continued detection of unusual strains is of great importance in the era of routine rotavirus vaccination. While zoonotic transmissions often represent sporadic cases, the sustained circulation of antigenically novel strains has the potential to challenge vaccine efficacy.