May 29 2024 Xinyang flavivirus is a novel tick-borne Orthoflavivirus

What sets XiFV apart from many other flaviviruses is its apparent restriction to an arthropod-only life cycle. While most flaviviruses are transmitted between ticks and mammals or birds, XiFV shows no evidence of such transmission. Its genome exhibits traits similar to insect-specific flaviviruses, reinforcing the idea that it might be confined to ticks. Notably, XiFV and its close relatives lack a crucial protein cleavage site found in flaviviruses that infect vertebrates, further suggesting their life cycle is restricted to tick populations.

On a structural level, XiFV shares several characteristics with other orthoflaviviruses, particularly in the formation of complex RNA structures in its 3′ untranslated region. These structures are known to play a role in viral replication and evasion of host immune defenses. Our findings add to the growing understanding that a distinct group of tick-borne flaviviruses might not need a vertebrate host to survive, opening the door to further research into their ecology and interactions with other pathogens.

As this new virus continues to be studied, it highlights the importance of understanding the diverse life cycles and evolutionary pressures shaping tick-borne viruses, which could have broader implications for public health and virology.