Global epidemiology of tick-borne Alpharhabdovirinae: a meta-analysis

The Alpharhabdovirinae subfamily of the family Rhabdoviridae encompasses a diverse and expanding group of tick-borne viruses, some of which pose potential risks as emerging human pathogens. Despite increasing detection through metagenomic surveillance, the global diversity, phylogenetic relationships, and taxonomic framework of tick-borne Alpharhabdovirinae (TBA) remain poorly characterized.

This study conducted a comprehensive meta-analysis of all publicly available TBA sequences based on phylogenetic analysis of five structural proteins (N, P, M, G, L), combined with host associations and geographic distributions.

345 TBA strains were classified into 12 distinct phylogenetic clusters, each exhibiting unique evolutionary and ecological characteristics. These clusters include: (1) seven species-level lineages within the genus Alpharicinrhavirus, predominantly associated with Hyalomma and Haemaphysalis ticks across Eurasia; (2) a cluster related to Manly virus, widely distributed in Amblyomma, Haemaphysalis, and Rhipicephalus ticks acrossAustralia and China, exhibiting additional protein-coding genes of unknown function; (3) the genus Ledantevirus (21 species), characterized by broad host tropism including bats, rodents, and humans, with some members displaying phosphoprotein phylogenetic anomalies suggestive of recombination; (4) the genus Lostrhavirus, together with Tongliao Rhabd tick virus 1, forming a cluster associated with Hyalomma and Amblyomma ticks; (5) a Mononegavirus cluster comprising Alpharicinrhavirus heilongjiang, Alpharicinrhavirus skanevik (Norway mononegavirus 1), and Mononegavirales sp. specifically associated with Ixodesticks in Eurasia; and (6) one clusters with incomplete protein repertoires and uncertain taxonomic positions, including Tahe rhabdovirus 3 and Yanbian Rhabd tick virus 1 which lacks phosphoprotein entirely. This study provide a refined phylogenetic framework for TBA viruses, clarify their evolutionary relationships, and highlight critical knowledge gaps, including numerous uncharacterized hypothetical proteins and incomplete genomes that warrant further investigation.

This study underscores the importance of enhanced global surveillance and genomic characterization to assess the emergence potential and public health threat posed by this diverse group of tick-borne viruses.