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In recent decades, many new flavi-like viruses have been discovered predominantly in different invertebrates and, as was recently shown, some of them may cause disease in humans. The Jingmenvirus (JMV) group holds a special place among flaviviruses and flavi-like viruses because they have a segmented ssRNA(+) genome. We detected Alongshan virus (ALSV), which is a representative of the JMV group, in ten pools of adult Ixodes persulcatus ticks collected in two geographically-separated Russian regions. Three of the ten strains were isolated in the tick cell line IRE/CTVM19. One of the strains persisted in the IRE/CTVM19 cells without cytopathic effect for three years. Most ALSV virions purified from tick cells were spherical with a diameter of approximately 40.5 nm. In addition, we found smaller particles of approximately 13.1 nm in diameter. We obtained full genome sequences of all four segments of two of the isolated ALSV strains, and partial sequences of one segment from the third strain. Phylogenetic analysis on genome segment 2 of the JMV group clustered our novel strains with other ALSV strains. We found evidence for the existence of a novel upstream open reading frame in the glycoprotein-coding segment of ALSV and other members of the JMV group.

A group of patients with a febrile illness and a history of tick bites was identified in northeastern China. A previously unknown virus was determined to be a possible etiologic agent. This virus was also found in ticks in the area.

Although segmented and unsegmented RNA viruses are commonplace, the evolutionary links between these two very different forms of genome organization are unclear. We report the discovery and characterization of a tick-borne virus—Jingmen tick virus (JMTV)—that reveals an unexpected connection between segmented and unsegmented RNA viruses. The JMTV genome comprises four segments, two of which are related to the nonstructural protein genes of the genus Flavivirus (family Flaviviridae), whereas the remaining segments are unique to this virus, have no known homologs, and contain a number of features indicative of structural protein genes. Remarkably, homology searching revealed that sequences related to JMTV were present in the cDNA library from Toxocara canis (dog roundworm; Nematoda), and that shared strong sequence and structural resemblances. Epidemiological studies showed that JMTV is distributed in tick populations across China, especially Rhipicephalus and Haemaphysalis spp., and experiences frequent host-switching and genomic reassortment. To our knowledge, JMTV is the first example of a segmented RNA virus with a genome derived in part from unsegmented viral ancestors.

Bussuquara virus (BSQV) was first discovered in the Brazilian Amazon in 1956. It is an arthropod-borne virus (arbovirus) in the genus Orthoflavivirus, family Flaviviridae. Since its discovery, BSQV has been sporadically detected across the South (Brazil, Columbia, and Argentina) and Central (Panama and Mexico) America and the Caribbean (Grenada), but there is minimal BSQV surveillance due to limited public health awareness and a lack of specific or sensitive diagnostics. BSQV exposure has been reported in a wide range of host and vector species, including humans. Little information is available in the literature and herein we summarize the published historical findings on BSQV and suggest a pathway for future studies to better understand its potential emergence into human populations.

Viral glycoproteins drive membrane fusion in enveloped viruses and determine host range, tissue tropism and pathogenesis 1 . Despite their importance, there is a fragmentary understanding of glycoproteins within the Flaviviridae 2 , a large virus family that include pathogens such as hepatitis C, dengue and Zika viruses, and numerous other human, animal and emergent viruses. For many flaviviruses the glycoproteins have not yet been identified, for others, such as the hepaciviruses, the molecular mechanisms of membrane fusion remain uncharacterized 3 . Here we combine phylogenetic analyses with protein structure prediction to survey glycoproteins across the entire Flaviviridae . We find class II fusion systems, homologous to the Orthoflavivirus E glycoprotein in most species, including highly divergent jingmenviruses and large genome flaviviruses. However, the E1E2 glycoproteins of the hepaciviruses, pegiviruses and pestiviruses are structurally distinct, may represent a novel class of fusion mechanism, and are strictly associated with infection of vertebrate hosts. By mapping glycoprotein distribution onto the underlying phylogeny, we reveal a complex evolutionary history marked by the capture of bacterial genes and potentially inter-genus recombination. These insights, made possible through protein structure prediction, refine our understanding of viral fusion mechanisms and reveal the events that have shaped the diverse virology and ecology of the Flaviviridae . Combined phylogenetic analyses and glycoprotein structure prediction across the Flaviviridae reveals divergent membrane fusion systems and provides insights into the complex evolutionary history within this family of viruses.

Equestrian sports play a significant economic role in the horse industry. In recent years, numerous equine viruses have emerged, among which are equine Pegiviruses and the re-emerging Equine coronavirus (ECoV). These viruses are distributed globally and primarily cause subclinical infections with unknown morbidity, even if ECoV can occasionally induce febrile and diarrheic episodes. To broaden the data on the Italian equine population, a study was conducted to assess their prevalence in two distinct horse populations belonging to the Carabinieri Corps (CC) and the Italian Army (IA) of the Italian Armed Forces (IAF). Samples consisted of blood serum and rectal swabs of 436 horses collected within the national surveillance program for equine infectious anemia and gastrointestinal parasite monitoring and analyzed for Pegivirus (caballi and equi) and ECoV by Real-Time RT PCR. The prevalence detected were 6.56% and 3.53%, respectively, for Pegivirus caballi and equi for the IA, while for the CC, they were 10.13% and 0.84%. Only one sample tested positive for ECoV belonging to a horse of the CC. Phylogenetic analyses were carried out on the PCR-positive samples that were sequenced using Sanger protocols. Understanding the epidemiology of these viruses is essential for evaluating the implementation of effective prevention strategies.

The emergence and spread of novel viral pathogens is a major threat to human health, particularly in the context of climate and human-induced change in land use. Alongshan virus (ALSV) is a tick-borne virus associated with human disease, which was first identified in northeast China. More recently, several studies reported the emergence of ALSV in mammalian and arthropod hosts in multiple different countries outside of Asia, and the first viral genome sequencing data has become available. ALSV is a member of the Jingmenvirus group closely related to the family. Unusually, the positive-sense, single-stranded RNA genome of ALSV is segmented and consists of four distinct segments, two of which show homology with the NS3 and NS5 protein encoding regions of non-segmented flaviviruses. Transmission of arthropod-borne pathogens will likely increase in the future due to environmental change mediated by a variety of environmental and ecological factors and increasing human encroachment into wild animal habitats. In this review, we present current knowledge of global ALSV distribution and emergence patterns, highlight genetic diversity, evolution and susceptible species. Finally, we discuss the role of this emerging tick-borne virus in the context of urbanization and global health.

Pestiviruses are plus-stranded RNA viruses belonging to the family Flaviviridae. They comprise several important pathogens like classical swine fever virus and bovine viral diarrhea virus that induce economically important animal diseases. In 2017, the last update of pestivirus taxonomy resulted in demarcation of 11 species designated Pestivirus A through Pestivirus K. Since then, multiple new pestiviruses have been reported including pathogens associated with disease in pigs or small ruminants. In addition, pestivirus sequences have been found during metagenomics analysis of different non-ungulate hosts (bats, rodents, whale, and pangolin), but the consequences of this pestivirus diversity for animal health still need to be established. To provide a systematic classification of the newly discovered viruses, we analyzed the genetic relationship based on complete coding sequences (cds) and deduced polyprotein sequences and calculated pairwise distances that allow species demarcation. In addition, phylogenetic analysis was performed based on a highly conserved region within the non-structural protein NS5B. Taking into account the genetic relationships observed together with available information about antigenic properties, host origin, and characteristics of disease, we propose to expand the number of pestivirus species to 19 by adding eight additional species designated Pestivirus L through Pestivirus S.

Orthoflaviviruses and alphaviruses are arboviruses responsible for human diseases in tropical and subtropical countries. We aimed to detect infections with arboviruses and to evaluate the ecological patterns related to these infections among non-human primates (NHPs) in southeastern Brazil. Of the 248 molecularly screened NHPs, 30 were infected with orthoflaviviruses, which highlighted hotspots of arboviruses. We identified genome fragments of orthoflaviviruses Orthoflavivirus denguei 1 (DENV-1), 2 (DENV-2) and 3 (DENV-3), Orthoflavivirus louisense (SLEV), Orthoflavivirus zikaense (ZIKV), and Orthoflavivirus flavi (YFV). No alphaviruses were detected. Amid a human outbreak of YFV, black-tufted marmoset ( Callithrix penicillata ) was identified as being infected. SLEV and ZIKV were found in saliva samples and rectal swabs obtained from NHPs, a potential route for non-vector transmission of these viruses. This is the first report of infection with SLEV in the golden-handed tamarin ( Saguinus midas ) as well as coinfections with ZIKV and DENV-3 in C. penicillata and with ZIKV and SLEV in black howler monkey ( Alouatta caraya ). The isolation of ZIKV and SLEV from the saliva of NHPs may suggest an alternative mechanism for the maintenance of these viruses within NHP communities, in addition to the conventional transmission by mosquitoes. These findings are fundamental to support public health policy decisions and to foster ongoing eco-epidemiological surveillance of arboviruses in the context of the human-animal interface.

Jingmen virus (JMV) is a group of viruses that belong to the Flaviviridae family. These viruses have been shown to cause widespread infections in various hosts and can lead to febrile illnesses in humans. Jingmen tick virus (JMTV) as an important member of the JMV group, has been detected in multiple countries worldwide and poses a significant threat to public health. This study utilized metagenomic sequencing technology to detect JMV in tick samples collected in Jiangsu Province. The results demonstrated the presence of JMTV in Jiangsu and identified two complete genomes (ZJ-7-4-2 and ZJ-7-9) from Haemaphysalis campanulate ticks. These gene sequences exhibited the highest sequence similarity to the known Japanese isolate of JMTV. Phylogenetic analysis showed that the JMTV identified in this study clustered within the same clade as the Japanese JMTV. In summary, this study reported for the first time that JMTV is prevalent in Jiangsu Province, China. These findings expand the known geographic distribution and genetic diversity of JMTV, providing new insights into its epidemiology and viral evolution.