Isolation of Huangpi tick virus 1 and assessment of potential zoonotic relevance

BACKGROUND: The global burden of tick-borne viral diseases (TBVDs) has significantly increased in recent decades, emerging as a critical public health priority due to their diverse pathogenic profiles, severe disease outcomes, and therapeutic challenges. Within the expanding landscape of tick-borne pathogens, the Orthonairovirus genus has gained particular scientific attention for its members' zoonotic capacity and clinical virulence. Orthonairoviruses are arboviruses that infect humans and animals, posing a serious threat for the spread of zoonotic diseases. Huangpi tick virus 1 (HpTV-1), a member of the genus Orthonairovirus, has been detected in ticks. METHODS: Haemaphysalis longicornis collected in 2023 from Central China were pooled for RNA-seq and reverse transcription quantitative polymerase chain reaction (RT-qPCR) screening. Genomes were assembled and viruses isolated in suckling mice and Vero E6. Replication kinetics, mouse pathogenesis, and 223 livestock sera were assessed. RESULTS: In the present study, we isolated HpTV-1 from Haemaphysalis longicornis in Central China. Viral genome and phylogenetic analyses placed HpTV-1 in a distinct clade close to the Songling and Tamdy viruses within the Nairoviridae family. In vitro experiments demonstrated that HpTV-1 infects a wide range of animal and human cell lines. Importantly, all infected C57BL/6 mice survived without overt signs of severe disease while developing only minor pathological lesions in specific organs (liver, spleen, and lungs). Serological surveys revealed HpTV-1 antibodies, including neutralizing antibodies, in 16.1% of the goats, suggesting that HpTV-1 can infect livestock. CONCLUSIONS: These findings suggest that HpTV-1 is an Orthonairovirus capable of infecting animals, highlighting its potential risk and the need for enhanced surveillance and research, particularly in Central China and other endemic regions.