Occurrence and genetic diversity of the zoonotic rat hepatitis E virus in small mammal species, Spain

Abstract

Rat hepatitis E virus (ratHEV-C1) is a newly zoonotic and globally distributed virus of increasing public health concern. Although rats of the genus Rattus are the main reservoir of this emerging virus, the role of other small mammals in the epidemiology of ratHEV-C1 in Europe is unknown as large-scale survey studies specifically assessing the circulation of ratHEV-C1 in these species have not yet been conducted. In this study, we examined active ratHEV-C1 infection in 514 animals from seven different small mammal species sampled throughout Spain. The presence of viral RNA was evaluated for ratHEV-C1 infection using RT-qPCRs in liver tissue. Sequencing and analysis of ratHEV-C1 shedding in faeces were carried out in positive animals. Viral RNA was detected in 15 individuals (mean Ct value: 34.5), supposing a frequency of 2.9% (95% CI: 1.8-4.8). We confirmed ratHEV infection in house mice (14.5%; 11/76), common voles (0.7%; 2/288) and garden dormice (25.0%; 2/8) and viral shedding in faeces in 36.4% (4/11) of positive house mice. Infected animals were detected in urban areas, small ruminant farms and rural areas throughout Spain. Our sequences showed a considerable genetic diversity, and they were closely related with ratHEV-C1 strains detected in human and rats from Spain, Germany and Hungary. Our study confirms that ratHEV is not limited to Rattus genus, identifying other rodents' species as potential host of ratHEV-C1 in Europe. Our results highlight the importance of continued surveillance in animals to fully understand the dynamics of ratHEV-C1 and its impact on public health.

Keywords: Rocahepevirus ratti; emerging; hepeviruses; host range; surveillance; zoonoses.

Figure 1

Phylogenetic tree constructed using the Neighbor Joining method (1000 replicates) with seqPCR-1 (A) or seqPCR-2 and 3 (B). The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. Only bootstrap values higher than 50 are shown. Circles indicate the sequences obtained in the present study, and each color represents a different animal species.