Distribution and Genetic Diversity of Hepatitis E Virus in Wild and Domestic Rabbits in Australia.

Maria Jenckel,Tanja Strive,Peter West,Ina Smith,Patrick L Taggart,Tegan King,Robyn N Hall

doi:10.3390/pathogens10121637

Abstract

In 2020, Hepatitis E virus (HEV) was detected for the first time in Australian rabbits. To improve our understanding of the genetic diversity and distribution of the virus, 1635 rabbit liver samples from locations across Australia were screened via RT-qPCR for HEV. HEV genomes were amplified and sequenced from 48 positive samples. Furthermore, we tested 380 serum samples from 11 locations across Australia for antibodies against HEV. HEV was detected in rabbits from all states and territories, except the Northern Territory. Seroprevalence varied between locations (from 0% to 22%), demonstrating that HEV is widely distributed in rabbit populations across Australia. Phylogenetic analyses showed that Australian HEV sequences are genetically diverse and that HEV was likely introduced into Australia independently on several occasions. In summary, this study broadens our understanding of the genetic diversity of rabbit HEV globally and shows that the virus is endemic in both domestic and wild rabbit populations in Australia.

Highlights

Hepatitis E virus (HEV) is a positive sense RNA virus in the genus Orthohepevirus
To investigate the presence of HEV in Australian rabbits, 1635 RNA samples extracted from Australian wild and domestic rabbit liver or bone marrow samples were screened for HEV via room temperature (RT)-qPCR
We found a 3.4% positivity based on RT-qPCR screening of tissue samples

Summary

Introduction

Hepatitis E virus (HEV) is a positive sense RNA virus in the genus Orthohepevirus. The genome is approximately 7200 bases in length and contains three open reading frames (ORF1, ORF2, ORF3), which encode two polyproteins (ORF1 and ORF2) and a small 113–115 amino acid protein (ORF3) [1]. While genotype 1 and 2 infections are only reported from humans, genotypes 3 and 4 can infect animals (pigs, rabbits, wild boar, deer) and are considered zoonotic [4]. Case fatality rates of 20–25% have been observed in pregnant patients infected with HEV genotypes 1 or 2 [5]. The main route of transmission is faecaloral. In developing countries human infections normally occur through contaminated water, while in developed countries the main route of transmission is via consumption of undercooked meat (usually pork) [6]. The identification of rabbit HEV (HEV3ra) in immunocompromised patients in France without any link to the consumption of rabbit meat suggests possible alternative routes of transmission that have not yet been identified [7,8]

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