Virology

The ubiquitin-conjugating enzyme UBE2J1 functions in the proteasomal degradation of proteins at the ER. Existing evidence suggests that it plays a role during viral infection, with elevated UBE2J1 levels generally associated with increased infection. This is particularly relevant for some RNA viruses; however, the regulation of UBE2J1 during infection has not been well studied. Here, we used a BHK21 cell model to demonstrate that UBE2J1 overexpression promotes the replication of Vesicular Stomatitis Virus (VSV), as indicated by a significant increase in viral titres. To better understand the underlying molecular processes, cells were co-transfected to express the VSV-G protein and wild-type UBE2J1 protein, and we observed a significant increase in the syncytial fusion area. This effect was not observed when catalytically inactive (C91S) or phospho-deficient (S184A) forms of the protein were used. Interestingly, overexpression of a truncated, non-ER localized form of UBE2J1 ({Delta}TM) led to the largest increase in the syncytial fusion area. This arose as a result of increased syncytia size, and may indicate an enhanced cellular role if soluble forms of UBE2J1 are not anchored to the ER. Additional studies using truncated, mutated and wild-type proteins confirmed that UBE2J1 increases VSV viral replication and is associated with an increase in the number of infection plaques. Considering the emerging evidence for UBE2J1 involvement in viral infection, our finding should help in understanding the role of this protein in viral pathogenesis and cellular processes linked to syncytialization.

Borealpox virus (BRPV; formerly Alaskapox) is an orthopoxvirus that has caused seven reported human infections in Alaska since 2015, including a fatal case in 2023. The natural reservoir of BRPV is unknown, although previous investigations have raised the possibility of wild small mammals transmitting the virus to humans, either through direct contact or via domestic cats and dogs. To understand which species may be involved in the maintenance and/or spillover of BRPV in Alaska, we trapped and sampled wild small mammals (including voles, shrews, and squirrels) in 2021 and 2024 near reported human case locations in Fairbanks and the Kenai Peninsula, respectively. We found evidence of previous exposure to orthopoxviruses in five species (including the House Mouse, Mus musculus) and detected BRPV DNA as well as viable virus in Northern Red-backed Voles (Clethrionomys rutilus). Further, screening of tissues from historical museum specimens revealed BRPV DNA in C. rutilus specimens collected in Denali National Park and Preserve in 1998 and 1999, 17 years before the first reported human case of BRPV. Phylogenomic analysis of all human and animal BRPV isolates strongly supports the hypothesis of local human infections through multiple spillover events. These findings suggest C. rutilus as a possible reservoir species for BRPV and indicate that BRPV has been present in Alaskan wild small-mammal populations for at least 25 years. Our study highlights the potential of museum collections to elucidate the temporal, spatial, and host ranges of emerging pathogens. Further museum- and field-based sampling will clarify the true geographic range of BRPV, which is closely related to Old World orthopoxviruses and may be circulating beyond North America.

Thogotoviruses are a group of tick-borne, six-segmented, negative-sense single-stranded RNA viruses. These viruses encode an RNA-dependent RNA polymerase that recognizes promoter sequences located at the genomic termini to initiate RNA synthesis. The 5' and 3' ends of the genome bind to the polymerase and function as a promoter. Outside the catalytic center, they base-pair with each other to form a double-stranded RNA structure. This structure is referred to as the distal duplex and plays an important role in RNA synthesis. In this study, we investigated how the RNA sequence of the distal duplex influences polymerase activity using minigenome systems of two thogotoviruses, Oz virus (OZV) and Dhori virus (DHOV). Each virus exhibits distinct activities among its six segments. In OZV, one determinant of these differences is the base pair at positions 5'12 and 3'11 within the distal duplex, where promoter activity varies depending on whether the base pair is G:C or A:U. In contrast, the DHOV polymerase is not affected by this difference. These results indicate that, even within the genus Thogotovirus, viruses differ in whether they possess a mechanism that modulates promoter activity based on subtle sequence differences within the distal duplex. Furthermore, phylogenetic analysis and comparison of promoter sequences suggest that thogotoviruses can be divided into groups that do or do not regulate intersegment promoter activity via the base pair at positions 5'12 and 3'11. HighlightsO_LIMinigenome systems of Oz virus and Dhori virus reveal segment-specific differences in promoter activity C_LIO_LIThe distal duplex sequence modulates RNA synthesis in a virus-dependent manner C_LIO_LIThe base pair at positions 5'12/3'11 determines promoter activity in Oz virus but not in Dhori virus C_LIO_LIThogotoviruses can be divided into groups that do or do not regulate promoter activity via distal duplex sequence variation at positions 5'12/3'11 C_LI

Avian influenza viruses (AIVs) are endemic in the Americas and responsible for outbreaks in both domestic and wild birds that occasionally spill over into humans. We report the first known outbreak of AIV H9N2 in lesser rhea (Rhea pennata), also known as Darwins rhea, in the region of Puno-Peru. The animals in this study lived in an isolated conservation center located in remote highlands above 4,000 m.a.s.l. Between June and July 2025, a total of 46/92 animals were recorded sick, with symptoms including greenish diarrhea (100%), hyporexia (24%), dyspnea (76%), nasal discharge (42%), drowsiness (18%) and isolation from the flock (73%), and 94% later died. Gross pathology exams revealed septicemia characterized by severe hepatitis, pneumonia, tracheitis, enteritis, and encephalitis. Swab and necropsy samples tested positive for Influenza A by PCR and were later identified as H9N2 through whole genome sequencing. We generated complete H9N2 genomes for two individuals. No additional pathogens were found. Phylogenetic analysis across all eight segments revealed that the viruses were low pathogenicity H9N2 AIV strains of North American origin, which indicated this outbreak was a new introduction of the virus into South America. We also performed a comparative mutational analysis and identified multiple mutations previously associated with mammalian host adaptation, increased virulence, increased pathogenicity, and increased virus binding to 2-6 receptors, which may explain the high mortality rates observed despite the supposedly low pathogenicity of the strain. We also identified novel mutations specific to rhea viruses that will need to be experimentally validated. This is the first report of a natural H9N2 systemic infection in an avian host, highlighting a need for increased surveillance efforts for zoonotic influenza viruses with pandemic potential. Author SummaryAvian influenza viruses (AIVs) are endemic in the Americas and cause more than 7,600 infections annually in domestic and wild birds worldwide each year. We report detection of AIV H9N2 in lesser rhea during an outbreak that occurred in June-July 2025 in the Andean highlands of Puno in Peru. Multiple sick animals were reported with symptoms of respiratory and gastrointestinal disease and 94% of them later died. Samples collected tested positive for Influenza A and they were subtyped as H9N2 of low pathogenic origin from North America. This is the third time H9N2 enters South America from North America, presumably through wild birds, some of which migrate along the Pacific Flyway. Comparison with other H9N2 sequences revealed a total of 44 mutations of interest that may explain the elevated death rates observed. Surveillance in wild birds remains patchy at best and needs to be strengthened in order to prevent spillover events into other animals, including humans.

Avian influenza virus (AIV) epidemiology is well-documented in temperate regions but remains poorly understood in isolated ecosystems like tropical oceanic islands. On these islands, seabirds nest in dense interspecific colonies where the role of different species as reservoirs and dispersers of AIV may vary greatly. Here, we examine the role of noddies (Anous spp.) as potential reservoirs for low pathogenic AIV and evaluate their potential as sentinel species for highly pathogenic AIV introduction on tropical oceanic islands. We analyzed blood samples from 11 seabird species across eight islands in the southwestern Indian Ocean (2015-2020). Noddies exhibited high, stable seroprevalence (30-45%), comparable to reservoir host species in temperate regions. The detection of two N7-positive noddies, sampled the same year on two distinct islands, provided direct molecular evidence that AIV actively circulates on these island colonies. While most other species showed low exposure, Bridled Terns (Onychoprion anaethetus) had exceptionally high seroprevalence (80%), though their reservoir status requires further investigation due to limited sampling. Given noddies consistent exposure and regional distribution, we recommend prioritizing islands with large noddy populations for AIV surveillance. Continued investigation of viral dynamics within and among islands is now called for to elucidate the ecological drivers of AIV maintenance and transmission.

Hepatitis D virus (HDV) is a satellite virus that utilizes hepatitis B virus (HBV) as a helper for infectious particle formation. HDV was originally identified as a novel antigen in liver biopsies of HBV patients, and later studies showed the "delta" antigen (DAg) to be the sole protein encoded by HDV. Until the discovery of HDV-like agents in birds and snakes in 2018, HDV was a unique example of animal satellite viruses. We identified Swiss snake colony virus 1 (SwSCV-1) in the brain of a Boa constrictor, and through comparison we found the genome organization of SwSCV-1 to resemble that of HDV. However, in addition to the DAg open reading frame (ORF), the genome of SwSCV-1 includes another >500 nt ORF, "ORF2". To study whether the putative ORF2-encoded protein plays a role in the SwSCV-1 life cycle, we established an infectious clone of the virus with a point mutation in the methionine initiation codon of ORF2. The mutation did not significantly affect initiation of replication, establishment of persistent infection, or infectious particle formation upon superinfection with a helper virus. Using additional methods, we gathered further evidence confirming that ORF2 is not actively translated in boa constrictor cells. We further showed that unlike HDV, SwSCV-1 expresses a single form of the DAg. Although the proteins encoded by SwSCV-1 and HDV only include one and two forms of the DAg, respectively, whether other kolmioviruses express additional forms of DAg or related proteins in some cell types or host species merits further research. IMPORTANCEApproximately 40 years after the discovery of hepatitis D virus (HDV), satellite viruses with similar genome organization were found in various animals, thereby giving rise to family Kolmioviridae. HDV encodes a single protein, the delta antigen (DAg), which comes in small and approximately 20 amino acids longer large form. The genome of some HDV species and many of the newly found kolmioviruses contains additional open reading frames (ORFs), potentially enabling protein expression. Here, we studied the viral proteins expressed during Swiss snake colony virus 1 (SwSCV-1) infection of boa constrictor cells. Our findings show that unlike HDV, SwSCV-1 encodes only a single form of DAg. In addition, our study suggests that, like in HDV, the additional ORF in SwSCV-1 genome does not give rise to a protein. Although we could not demonstrate expression of additional viral proteins during SwSCV-1 infection, it is important to study the proteome of other kolmioviruses.

Bacteriophage (phage) collections are essential resources for studying virus-host interactions in bacterial species. Here, we report six Escherichia coli-infecting phages that expand the Lund Collection of Bacteriophages. These phages were isolated in 2025 within the framework of the School of Molecular and Theoretical Biology for high-school students, from samples collected in Lake Taldykol, Astana, Kazakhstan, using E. coli strains MG1655{Delta}RM and EV36 as hosts. The isolated phages comprise Taldykol (LuPh6), a member of the genus Kagunavirus; Aidakhar (LuPh7) of the genus Phapecoctavirus; Samruk (LuPh8) of the genus Tequintavirus; the T-odd-like phage Baiterek (LuPh9) of the genus Vequintavirus; and two T-even-like phages Tulpar (LuPh10) and Shurale (LuPh11) that belong to the Tequatrovirus genus. This expanded phage collection enhances the toolkit for investigating phage-host interactions and their molecular mechanisms and highlights the use of phage isolation as a component of high school research education. ImportancePhage collections are a key resource for studying phage biology, phage-bacteria interactions and bacterial immune systems. Here, we extend the Lund Phage Collection through the isolation and characterisation of six E. coli-infecting phages, including three novel species (LuPh6, LuPh8 and LuPh11) as well as a member of the genus Phapecoctavirus that not represented in widely used collections such as BASEL (LuPh7). This study expands the resources available for probing phage-host interactions and demonstrates an example of integrating phage research into education of high school students.

Insects are associated with diverse RNA viruses, including vertically transmitted viruses that form persistent infections without apparent symptoms. One of the first documented vertically transmitted viruses is sigmavirus (Rhabdoviridae) affecting fitness of Drosophila. Sigmaviruses and related rhabdoviruses have also been detected in pest fruit flies and other arthropods. However, their prevalence, transmission, tissue localisation and fitness effects remain poorly known, despite their potentially common infections in diverse hosts. We investigated Sigmavirus tryoni (BtSV) prevalence, load, transmission across multiple generations and host effects in Queensland fruit fly (Bactrocera tryoni), Australias most significant horticultural pest, which carries BtSV at low prevalence (13.7%) across field populations. We detected BtSV in 6 of 12 laboratory populations (prevalence 12.5% to 80.4%) where it was transmitted biparentally within embryos. Although incomplete, maternal transmission was more reliable and resulted in higher BtSV load than paternal transmission. Paternally transmitted BtSV was almost entirely lost after two generations. BtSV became detectable in most uninfected individuals cohabiting with infected flies, but this resulted in a low load that was subsequently transmitted to only few offspring. BtSV occurred across developmental stages, digestive and reproductive tissues, albeit its viral load was lower in reproductive tissues when received paternally than maternally, and lower in testes than ovaries. Furthermore, BtSV-infected individuals suffered paralysis and mortality when exposed to high CO2 concentrations, a Rhabdoviridae effect previously reported for several Drosophila species, a muscid fly and mosquitoes. Our study suggests that sigmavirus transmission dynamics and fitness effects may apply broadly to arthropod hosts and affect their management.

Peste des petits ruminants (PPR) is a highly contagious viral disease of small ruminants caused by the peste des petits ruminants virus (PPRV), which is classified into four distinct genetic lineages (I-IV). A critical concern in the recent epidemiological history of PPRV is the rapid and widespread expansion of lineage IV (LIV) across West Africa over the past decade. This dominance suggests a potential adaptive advantage of circulating LIV strains in the regions current epidemiological context. In this study, we obtain the genome sequence of 26 new PPRV samples, including historical (pre-2000) and many recent African LIV isolates, offering the first opportunity to investigate the evolutionary history of LIV in Africa and identify genetic events potentially associated with its recent spread. Phylogenomic analyses implemented on a dataset of 167 curated PPRV genome sequences reveal that the most ancestral LIV group comprises strains circulating in Sub-Saharan Africa (designated clade LIVssa), providing robust evidence for an African origin of lineage IV. Our results further indicate that PPRV strains linked to the recent West African expansion of LIV belong to a specific LIVssa subgroup, termed NigB. We identified multiple signatures of selection pressure within the LIVssa sublineage, particularly in the NigB cluster. Several amino acid substitutions unique to LIVssa or NigB were detected, some of which may impact protein function and warrant prioritised investigation. Additional genomic data are required to confirm the association between the NigB group and the ongoing spread of LIV in West Africa. The evolutionary adaptations observed in LIVssa - potentially enhancing transmission efficiency, host range or pathogenicity - could undermine current disease control strategies in regions where PPR poses significant threats to food security and local economies. Author SummaryPeste des petits ruminants virus (PPRV) infects sheep and goats across Africa, Middle East, Asia and Europe, causing disease with major impact on global economy and food security. One genetic lineage of PPRV, called lineage IV (LIV), is at the origin of most recent expansion of the distribution of the disease, including replacement of other lineages in areas of African where PPRV is historically present. Here, we generated genome sequences from PPRV LIV isolates from different dates and places to study the evolution of this genetic lineage and explore whether its recent spread can be associated with the appearance of new mutations in the virus genome. Our results provide evidence that the PPRV LIV originated in Sub-Saharan Africa and identify mutations present only virus isolates currently spready in new regions of Africa. Further research should investigate the impact of these mutations on protein functions and capacity of transmission of PPRV.

This novel study detected persistent low level infections of Elephant Endotheliotropic Herpesviruses (EEHV), that can cause highly pathogenic Elephant Hemorrhagic Disease (EHD) in Loxodonta and Elephas, and co-infection of presumed less pathogenic Elephant Gammaherpesviruses (EGHV), in skin nodule biopsies, saliva and tissues collected from 43 wild L. africana (savannah elephant) in Botswana, Kenya, South Africa and Zimbabwe; in saliva from 25 wild L. cyclotis (forest elephant) in Gabon; and in saliva collected over seven years from 7 wild-born L.africana at Six Flags Safari Park, USA; and in saliva, blood and tissues from an additional 200 L. africana in USA zoos. DNA from these samples was extracted in our USA laboratories and amplified by conventional polymerase chain reaction using three-round nested primer sets designed specifically to screen for known EEHV and EGHV genes loci and to discover new species and subtypes. Sanger sequencing of purified DNA from nearly all samples yielded unambiguous positive genetic matches to previously known Loxodonta-associated EEHV2, EEHV3A, EEHV3B, EEHV6, EEHV7A, and EGHV1B, EGHV2, EGHV3B, EGHV4B, EGHV5B and discovered novel types EEHV3C-H and EEHV7B and the prototype EGHV1B. Many of the primer sets used could also have detected known Elephas-associated EEHV1A, EEHV1B, EEHV4, and EEHV5 if present in these samples, but they did not. Our extensive library of EEHV and EGHV sequences from wild and zoo Loxodonta, (as well as from 100 zoo Elephas maximus not discussed in this review), is a significant contribution to the elephant virology community, particularly for comparing subtypes types of EEHV found in pathogenic cases of EHD in zoos as well as determining and comparing species and subtypes of EEHV present in existing zoo herds, and in individual elephants being transported between zoos, and for importation of wild elephants into existing zoo herds.

We prepared siRNA libraries against the H5N2 virus NP gene, and the PA, PB1 and PB2 genes that express the proteins that form the virus polymerase complex. The antiviral activity of the siRNA libraries in H5N2 virus infected cells was initially assessed by using qPCR to measure the corresponding mRNA levels in the siRNA-treated cells. In this way siRNA molecules within each library were identified that exhibited to a greater than 70% reduction in levels of each target mRNA. A selection of these siRNA molecules was further evaluated for their antiviral activity in a multi-cycle H5N2 MDCK cell model. The siRNA molecules identified were successful in blocking virus transmission and lead to a reduction in influenza virus progeny virus production. This antiviral activity correlated with both the inhibition of nuclear export of the newly formed RNP complexs that arise from the transcriptional activity of the input virus, and the inhibition of the polymerase activity of the newly formed virus polymerase complexes. This study highlights the potential use of siRNA as a strategy to block virus transmission by targeting the avian influenza virus polymerase complex.

RNA viruses are common in tephritid fruit flies including the Queensland fruit fly, Australias most significant horticultural pest. For many their transmission, tissue tropism and load across host development remain unexplored. Yet these factors are important for host biology, ecology and pest management. We investigated Bactrocera tryoni orbivirus (OV), Bactrocera tryoni xinmovirus (XV), Bactrocera tryoni toti-like virus (TLV) and Bactrocera tryoni iflavirus species 2 (IVsp.2) that commonly coinfect B. tryoni laboratory populations. OV and XV transmission was vertical within and on eggs, while TLV transmission was vertical within eggs. IVsp.2 was not detected in eggs but was present in adults; however, IVsp.2 was horizontally transmitted, with viral load increasing with cohabitation time with infected flies. Horizontal transmission was not observed for the other viruses. OV had a similar load across all tissues, while XV was consistently more abundant in ovaries. TLV had a high viral load in the brain whereas IVsp.2 was abundant in the thorax, foregut and midgut. Besides differences in eggs, the viruses were detected in all other developmental stages, but viral load patterns differed: viral load remained constant for TLV, fluctuated for OV and XV, and was low in pre-adult stages and high in adults for IVsp.2. Our findings demonstrate distinct transmission strategies and tissue tropism among the viruses, providing new insights into their epidemiology and role in host biology. Furthermore, contrary to prevailing views that viruses are generally horizontally transmitted, most known RNA viruses of B. tryoni are vertically transmitted affecting the evolution of host-virus interactions.

Defective interfering particles (DIPs) derived from the influenza A virus (IAV) are a promising antiviral agent due to their strong antiviral efficacy demonstrated in various animal models. OP7 is an unconventional IAV DIP with multiple point mutations in the viral RNA (vRNA) of genome segment 7, as opposed to the large internal genomic deletions typically found in conventional IAV DIPs. Further, OP7 showed an even higher interfering efficacy than conventional DIPs. However, the inhibitory effect of OP7 on standard virus (STV) replication has primarily been investigated in Madin-Darby Canine Kidney (MDCK) cells, which lack a functional myxovirus resistance (Mx)-mediated antiviral activity against IAV. In this study, we examined the antiviral activity and mechanism of antiviral action of OP7 in an interferon (IFN)-competent human lung carcinoma cell line (Calu-3) in vitro. We performed STV and OP7 co-infection experiments using a variety of infection conditions and measured the time-resolved dynamics in viral titer, vRNA, protein level, and host cell gene expression. We observed that OP7 co-infection results in enhanced type I IFN responses and markedly reduced infectious virus release, even at low doses. Additionally, we found that at a high STV multiplicity of infection (MOI), the replication interference of OP7, suppressing the replication of STV vRNA, appears to be the dominant mechanism of its antiviral action. At a low MOI, however, IFN induction seems to be more important. Furthermore, we examined the efficacious co-infection time window for potential prophylactic and therapeutic antiviral treatment. We observed an antiviral effect exerted by OP7 infection for up to seven days before STV infection and up to 24 hours after STV infection. Together, these findings demonstrate that OP7 is a potent antiviral DIP. Therefore, this work supports the further development of OP7 as a therapeutic and prophylactic antiviral agent.

Hydrangea ringspot virus (HdRSV) is an emerging plant virus infecting ornamental hydrangea species worldwide, yet its genomic diversity and host associations remain poorly understood. To expand the available genomic resources and assess HdRSV variability, we screened 210 publicly available Hydrangea spp. transcriptomes from diverse tissues, complemented with four newly generated H. macrophylla transcriptomes from Colombia. Viral genomes were assembled from infected samples and analyzed to infer phylogenetic relationships, lineage distribution, and relative viral RNA abundance. Two well-supported phylogenetic lineages (HdRSV-L1 and HdRSV-L2) were recovered from both full-genome and replicase coding sequence (CDS) analyses. HdRSV was detected across all host tissues examined, with the highest median viral loads in roots, followed by stems and leaves. H. macrophylla harbored both viral lineages, while H. serrata was exclusively infected by HdRSV-L1. Cultivar-level analysis revealed marked differences in viral abundance, with lineages showing distinct tissue preferences but no co-infection patterns, except in the Bailer cultivar. Comparative analysis of the replicase CDS identified a single lineage-defining nonsynonymous mutation (C1578T; Thr[->]Ile), fixed in 90% of HdRSV-L2 genomes, corresponding to a polar-to-nonpolar amino acid change potentially associated with structural adaptation. Together, these findings provide the most comprehensive overview to date of HdRSV genomic diversity, host and tissue distribution, and molecular variation, offering new insights into the evolution and epidemiology of this understudied plant virus.

Dairy cattle have emerged as a prolific amplifying host for highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b and a new source for cross-species and zoonotic transmission. Independent introductions of H5N1 with unclear exposure routes have been reported in several dairy herds across the U.S. These events escalate the pandemic potential of HPAIV H5N1 as transmission within and between mammalian species present opportunities for mammalian adapted H5N1 viruses to emerge. Although more than 1000 herds have been infected, bovine H5N1 influenza virus pathogenesis, transmission, and evolution in dairy cattle remains not well characterized. Working with H5N1-infected lactating cattle in high containment has been a major challenge due to the required infrastructure and logistics associated with housing, husbandry, and waste management for this model. Thus, developing alternative bovine models that maintain biological relevance while reducing operational complexity is warranted. Here we evaluate the susceptibility of lactating Jersey cattle in the dry-off period and characterize the effect of inoculation dose on the mammary pathogenicity of HPAIV H5N1 genotype B3.13. The results of this study demonstrate that dairy cows 21 days into the dry-off period are highly susceptible to HPAIV H5N1, recapitulating the severe clinical and pathological outcomes observed in infected lactating cows under experimental conditions and in field cases. We also observed an association between virus dose and the onset and severity of mastitis in individual udder-quarters and compartmentalized clonal expansion of variant populations. Overall, this study demonstrates that dry cows can provide a feasible model to study H5N1 virology, pathology, and humoral immunology in dairy cows.

We recently reported the identification of endogenous viral elements (EVEs) originating from the Caulimoviridae family within the alfalfa (Medicago sativa L.) genome. Our subsequent identification of ubiquitous rhabdoviral elements in infected and healthy alfalfa tissues by high throughput sequencing prompted us to suggest that the alfalfa genome might be populated with integrated rhabdoviruses as well. Bioinformatics analysis using 26 publicly available alfalfa genomes proved the suggestion accurate. We found multiple non-retroviral segments of the Rhabdoviridae family belonging to the genera Betanucleorhabdovirus and Betacytorhabdovirus that appeared to be stable constituents of the host genome. In that capacity they could potentially acquire functional roles in alfalfas development and response to environmental stresses. We believe this study reveals the first documented case of rhabdoviruses integrated into the alfalfa genome.

Tomato brown rugose fruit virus (Tobamovirus fructirugosum) is an emerging virus that affects tomatoes, capsicum, and chili. Since its first detection in Jordan in 2015, the virus was reported in more than 40 countries across all the continents. In Morocco, the virus was reported for the first time in October 2021. However, its genetic diversity remains unexplored. In this work, we used a collection of tomato fruits from local markets to investigate the variability of the virus in the country. We explored the different pressures acting on the N-terminus of the RNA-dependent RNA polymerase, the movement protein, and the coat protein genes. Then, we used haplotype network analyses to reveal the population structure within the Moroccan isolates and studied their relationships with the ones from the world. We found that genetic diversity is low, which is consistent with the global situation. No signatures of diversifying selection were detected across the analyzed genes. However, the virus sequences from Morocco showed a clear geographic structure, suggesting that geographic factors probably combined with agricultural practices may contribute to shaping the population structure of ToBRFV in Morocco.

Sudan virus (SUDV) is a member of the family Filoviridae, which comprises highly pathogenic viruses associated with unusually high case fatality rates. The development of medical countermeasures against filoviruses, including antivirals, vaccines, and therapeutic antibodies, requires preclinical evaluation in suitable animal models. C57BL/6J IFNAR-/- mice, which lack the type I interferon (IFN-/{beta}) receptor, have been reported to be susceptible to filovirus infections, although their impaired innate immune response may represent a potential limitation of the model. Here, we show that IFNAR-/- mice constitute a suitable model for SUDV infection. Following infection, animals developed a clear clinical disease characterized by significant weight loss and pronounced changes in behaviour and appearance. Mice reached the predefined clinical endpoint 3-5 days post infection. Post mortem analysis of terminal samples revealed high viral loads and viral genome copies in all tested organs as well as in serum, indicating widespread systemic dissemination. Importantly, infection was associated with a marked increase in several key chemokines and cytokines linked to systemic inflammation, consistent with the development of a cytokine storm-like response. Together, these findings demonstrate that SUDV infection in IFNAR-/- mice induces systemic viral dissemination and a pronounced inflammatory response, supporting the suitability of this model for investigating filovirus pathogenesis and infection-associated immune dysregulation.

The yerba mate psyllid (Gyropsylla spegazziniana) poses a significant threat to yerba mate crops, causing extensive economic losses. While some ecological aspects as well as control strategies have been studied, its associated viral diversity remains unexplored. Here, by generating the first RNA high-throughput analysis (HTS) of this pest, we explored the G. spegazziniana virome, revealing novel and diverse RNA viruses. We characterized five new viral members belonging to distinct families, with evolutionary cues of beny-like viruses (Benyviridae), picorna-like viruses (Picornaviridae), and sobemo-like viruses (Solemoviridae); which were tentatively named Gyropsylla spegazziniana beny-like virus 1 (GSBlV1), Gyropsylla spegazziniana picorna-like virus 1 (GSPlV1), and Gyropsylla spegazziniana sobemo-like virus 1-3 (GSSlV1-3), respectively. Phylogenetic analysis of the bi-segmented and highly divergent sobemo-like viruses showed a distinctive evolutionary trajectory of its encoding proteins at the periphery of recently reported invertebrate Sobelivirales. The beny-like virus belonged to a cluster of insect-associated beny-like viruse; while the picorna-like virus clustered together with psyllid-associated picorna-like viruses. These results highlight the existence of a complex virome within G. spegazziniana and establish the basis for future studies investigating the ecological roles, evolutionary dynamics, and potential biocontrol applications of these viruses in the G. spegazziniana -yerba mate eco-systems.

Recent advances in sequencing technology and transcriptome mining have revealed highly divergent hepaciviruses in birds. However, only a limited number of avian hepaciviruses have been identified to date, leaving their diversity and evolutionary history poorly understood. Moreover, deep phylogenetic gaps among known avian hepaciviruses suggest that additional lineages remain undiscovered. Here, we screened publicly available RNA-seq data and identified three previously undescribed hepaciviruses from rock pigeon (Columba livia), rusty-margined flycatcher (Myiozetetes cayanensis), and Hispaniolan amazon (Amazona ventralis), named rock pigeon hepacivirus (RpHV), rusty-margined flycatcher hepacivirus (RfHV), and Hispaniolan amazon hepacivirus (HaHV). Although these three viruses meet the ICTV species demarcation criteria relative to their closest known relatives, the NS5B-based criterion was not satisfied between RfHV and HaHV. Notably, however, their genome sequence identity is low at 43.2%, and their hosts differ at the order level, suggesting that their classification warrants further consideration. Our phylogenetic analysis showed that avian hepaciviruses, including those found in this study, are monophyletic, but phylogenetic incongruence was observed between avian hepaciviruses and their hosts, suggesting past cross-species transmission among avian hepaciviruses. Overall, this study provides novel insights into the diversity and evolution of hepaciviruses.