Alongshan virus in the virome of Ixodes hexagonus ticks in the United Kingdom

Ticks host a vast spectrum of viruses, including many known pathogens and a growing number of virus species with unknown pathogenic potential. In this study we analysed the virome of Ixodes hexagonus ticks collected from European hedgehogs. Nucleic acids were extracted from the ticks, and a selection of hedgehog organs and RNA samples from three ticks were subjected to next generation sequencing. Sequence reads were de novo assembled and screened using viral detection software. Sequences flagged as potential viruses were compared to the NCBI virus database to identify the closest known viruses. In three I. hexagonus, the complete sequence of all four segments of Alongshan virus (ALSV) could be assembled. Previous phylogenetic analysis of ALSV isolates identified three clades derived from Europe, Central Asia and Eastern Asia. The ALSVs identified in the UK clustered phylogenetically within the European clade of ALSV and appear to be basal within this group. Subsequent RT-PCR screening of RNA samples from I. hexagonus, Ixodes ricinus and hedgehog tissues only detected ALSV RNA in I. hexagonus samples. Alongshan virus is a recently described segmented virus classified within the Jingmenvirus group (Family Flaviviridae) and has zoonotic potential. The virus was first detected in China in a human patient with febrile illness and encephalitis following a tick bite. Findings of this study suggest that I. hexagonus ticks carry ALSV and the virus is established in multiple locations in the UK. Importantly, I. hexagonus occasionally bites humans and companion animals and therefore poses a zoonotic risk.