Detection and Characterization of Homologues of Human Hepatitis Viruses and Pegiviruses in Rodents and Bats in Vietnam

Van Nguyen, Dung; Van Nguyen, Cuong; Bonsall, David; Ngo, Tue Tri; Carrique-Mas, Juan; Pham, Anh Hong; Bryant, Juliet E.; Thwaites, Guy; Baker, Stephen; Woolhouse, Mark; Simmonds, Peter

The high prevalence of hepacivirus in bamboo rats also indicates the need to reconsider transmission routes of hepaciviruses. Among hepaciviruses, the transmission route of HCV has been relatively well studied, while those of other hepaciviruses are mostly speculative [38, 39] . As a bloodborne virus, HCV is thought to be mainly transmitted through injections or blood transfusion. However, this does not explain how a range of divergent HCV strains have been maintained for centuries in some rural populations in central Africa and southeast Asia [40] . Equine hepacivirus has been shown to be transmittable via direct inoculation [41] and via vertical transmission [42] . Rodent hepacivirus may utilize a similar transmission route as experimental intravenous injection of the supernatants of homogenised liver tissues from infected rats lead to viraemia [43] . The high prevalence of hepacivirus in bamboo rats (in this study) and commensal Rattus norvegicus (23.3% in Firth et al. 2014 [18] ) indicates other more efficient transmission routes may exist such as via saliva and bites, The zoonotic potential of the detected viruses is unknown and requires further investigation. While the identified rodent hepaciviruses appear host species specific, four rodent species were infected with highly similar HEV homologues, which were phylogenetically interspersed, indicative of low host species specificity. This is a characteristic that may lead to their establishment and emergence in new hosts. Understanding the receptor usage for cell entry of HEV in rodents and other host species would potentially help predict the host range of the virus. Furthermore, a surrogate assay with pseudotyped viruses carrying surface/envelope proteins of the identified viruses may be useful in assessing their potential to infect human liver cells. Such an assay was used to show that a bat HBV could infect primary human hepatocytes [6] .