E-Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2021

Genetic characterisation of zoonotic rotavirus strains identified in children and adults with acute rotavirus gastroenteritis in Australia   (#211)

Celeste M Donato 1 2 3 , Elena Demosthenous 1 2 , Susie  Roczo-Farkas 1 , Sarah Thomas 1 , Rhian Bonnici 1 , Nada Bogdanovic-Sakran 1 , Carl D Kirkwood 1 3 4 , Julie E Bines 1 3 5
  1. Enteric Diseases Group, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
  2. Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia
  3. Department of Paediatrics, University of Melbourne, Parkville, 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 is capable of infecting both human and animal hosts, and zoonotic transmissions between species can occur. Rotavirus strains are classified into G and P genotypes based on the two outer capsid proteins; with 36 G types and 51 P types characterised from humans and animal species. Whole genome sequencing allows for the classification of all 11 genes to describe genome constellations and reassortment events.  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 

Samples with unusual genotype combinations (N=100) 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.  Maximum likelihood and Bayesian phylogenetic analysis was performed.  

 

Results 

In this study, G3P[3] 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 effectiveness.