Bacteriophages or bacteria infecting viruses are genetically diverse. Due to the emergence of antimicrobial-resistant bacteria, lytic bacteriophages are gaining enormous attention for treating superbug infections. Klebsiella pneumoniae is one of the eight most significant nosocomial pathogens and is addressed as a critical priority pathogen by WHO, requiring alternative treatment options. We reported two highly lytic bacteriophages, Klebsiella phage Kpn BM7 and the novel Klebsiella phage Kpn BU9, isolated from hospital wastewater and exhibiting lytic activity against different clinical isolates. Whole-genome analysis revealed that phages BM7 and BU9 belong to class Caudoviricetes. Phage BM7, with a genome length of 170,558 bp, is a member of the genus Marfavirus and the species Marfavirus F48. While phage BU9, with a genome length of 60,450 bp, remains unclassified. Neither phage harbors any lysogenic, toxin, or antimicrobial resistance genes. Both phages can steadily survive up to 40 °C and at pH 5-7. The optimal MOI was 0.1 for BM7 and 1 for BU9, with short latent periods of 10 and 25 min and burst sizes of 85 PFU/cell and 12 PFU/cell, respectively. This is the first carbapenem-resistant K. pneumoniae targeting lytic phages to be reported from Bangladesh. This study suggests that BM7 and BU9 are potential candidates for targeting carbapenem-resistant K. pneumoniae.

Glucocorticoid receptor (GR) activation enhances Human alpha-herpes virus 1 (HSV-1) replication and explant-induced reactivation from latency. Furthermore, GR and Krüppel-like factor 15 (KLF15) cooperatively transactivate cis-regulatory modules (CRMs) that drive expression of infected cell protein 0 (ICP0), ICP4, and ICP27. KLF and specificity protein (Sp) family members bind GC-rich or C-rich sequences and belong to the same super-family of transcription factors. Based on these observations, we hypothesized CRMs spanning the ICP0 promoter are transactivated by GR and Sp1 or Sp3. CRM-A (-800 to -635), CRM-B (-485 to -635), and CRM-D (-232 to -24), but not CRM-C, were significantly transactivated by GR, DEX, and Sp1 or Sp3 in mouse neuroblastoma cells (Neuro-2A). Mutagenesis of Sp1/Sp3 binding sites were important for transactivation of CRM-A and CRM-B. Chromatin immunoprecipitation studies revealed significantly higher levels of GR occupied ICP0 promoter sequences when Sp1 or Sp3 was over-expressed suggesting these transcriptions factors recruit GR to ICP0 CRM sequences. Mithramycin A, an antibiotic that preferentially binds GC-rich DNA and impairs Sp1/Sp3 dependent transactivation and reduced virus shedding during reactivation from latency in mice latently infected with HSV-1. These studies indicate GR and certain stress-induced cellular transcription factors preferentially bind GC rich DNA, which stimulates HSV-1 gene expression and reactivation from latency in trigeminal ganglia of latently infected mice.

Zika virus (ZIKV) is a major public health problem worldwide. After several reported outbreaks, the current extent of infections caused by this orthoflavivirus in the Sahel remains to be explored. We investigated the prevalence of neutralizing antibodies against ZIKV in the general population, in HIV-infected individuals and in livestock in Chad using a seroneutralization assay that ensures high specificity level. In this retrospective serological serosurveillance investigation, we estimated the neutralizing seroprevalence to be approximately 26 % (18/69) in healthy Chadian participants and 17 % (16/94) in HIV-infected individuals, with no statistical difference between these two subgroups or genders. In addition, we found an overall ZIKV prevalence of 14 % (8/59) in small ruminants (sheep and goats) living in the Lake Chad Basin area, demonstrating virus circulation in animals. Our pilot study shows for the first-time evidence of ZIKV circulation in humans and in livestock in Chad in close interaction with humans, and highlights the main challenges associated with this virus in Sahelian areas.

Infectious bronchitis virus (IBV) does not only cause disease in millions of chickens worldwide, but IBV-like viruses have also been detected or isolated from other domestic birds. We propose that the pheasant coronavirus (PhCoV) originates from IBV. Indeed, the IBV strains H120 and M41 can replicate but do not cause disease in pheasants. In this study, we found that three chicken nephropathogenic IBV strains, including ck/CH/LDL/091,021, ck/CH/LDL/140,520, and I0305/19, and the viruses recovered from the tissues of pheasants challenged with each IBV strain could replicate in some challenged pheasants with different capacities but could not cause disease. Overall, these viruses showed different capacities of replication and adaptation in pheasants, and the neutralizing antibody against each IBV strain could be detected in different numbers of pheasants challenged with each of the viruses, although the titers were generally low with large variation. Comparatively, ck/CH/LDL/140,520 and 20/P1-D5/Tr1 showed higher adaptation capacities in pheasants. Furthermore, the three IBV strains gained an increased capacity for adaptation when they passed in pheasants once, especially strain ck/CH/LDL/140,520, which gained an increased capacity for adaptation and extended tissue tropism when it was passaged in pheasants. Similar to IBV in chicken, the subpopulations within the virus were selected when the virus replicated and was passaged in pheasants, and the accumulation of mutations and deletions in the genome of each virus subpopulation accounted for the independent evolution of the virus in different tissues of pheasants. Taken together, we suggest that the phCoVs might originate from IBV through interspecies transmission from chickens to pheasants, before gaining increased tissue tropism, adaptation capacities, and disease-causing behaviors in pheasants during intraspecies transmission.

Equine infectious anemia virus (EIAV) is an equine lentivirus related to human immunodeficiency virus type 1 (HIV-1). Both viruses are related among the Retroviridae family, but their clinical manifestations are different as EIAV causes a long persistent infection with no progressive immune dysfunction in most cases. Today, no treatment is approved against EIAV, contrary to HIV-1, manageable through antiretroviral therapy, known as HAART (highly active antiretroviral therapy) or cART (combination antiretroviral therapy). No information about the efficacy of antiretroviral drugs against EIAV is available in the literature. This study evaluates the in vitro antiviral effect of eighteen FDA-approved antiretroviral compounds from different drug families, in an equine cells in vitro infection model with EIAV reference strain. Equine dermal cells, as well as equine peripheral blood mononuclear cells were treated with non-cytotoxic drug concentrations and infected with EIAV. Relative virus release in culture supernatants was assessed through relative quantification of viral RNA via RTqPCR and viral DNA comprising proviral integration in the cell genome was assessed through qPCR of infected cells, both after nucleic acid extractions. Out of eighteen tested drugs, thirteen showed a significant antiviral effect against EIAV in vitro, an interesting discovery showing the similarities between HIV-1 and EIAV and opening a possibility to treat equine infectious anemia to avoid the disease spread.

Wesselsbron is a neglected, mosquito-borne zoonotic disease transmitted by several species of virus-infected Aedes mosquitoes endemic to tropical regions in Africa. It affects primarily domestic livestock species with teratogenic effects, but can jump to humans. Herein, we investigated the molecular epidemiology of Wesselsbron virus in Africa using whole genome sequencing and structural analysis, and assessed its pathogenicity and tropism through in vivo experiments. A total of twenty-five isolates collected from three countries were successfully characterized. Our study is noteworthy by identifying, for the first time, inter-clade recombination events on the genome of Wesselsbron virus. However, more investigations on the precise molecular mechanisms conducting the occurrence of recombination on the genome of Wesselsbron virus, are warranted. The identification of polymorphisms on motifs of virulence and selection pressures on major proteins showed evidence of genetic evolution for Wesselsbron virus. The clade 1 was more pathogenic and neurotropic in suckling mice and the intramuscular route was found to be the best transmission mode. Our findings also provide new insights in the pathogenicity and tropism of Wesselsbron virus, which could be useful for prevention, preparedness and future outbreak response. Considering its high prevalence in mosquito populations and the increasing number of sporadic human cases, Wesselsbron virus merits more attention in terms of prevention and preparedness, as its mosquito vectors continue to globally expand and there is no vaccine.

Bluetongue (BT) and Epizootic Hemorrhagic Disease (EHD) are two notifiable animal diseases transmitted to ruminants by small hematophagous midges belonging to the Culicoides genus. The etiological agents, Bluetongue virus (BTV) and Epizootic hemorrhagic disease virus (EHDV), are both members of the Sedoreoviridae family and Orbivirus genus, which include double-stranded (ds) RNA segmented genomes (10 segments). By the end of the summer 2023, first's outbreaks of EHD were reported from the south west of France, concurrently with unexpectedly severe BT cases in Central France and Corsica. Within a few weeks, numerous BT and EHD outbreaks were recorded with significant sanitary and economic impact on cattle and sheep farms (no sanitary impact of EHD for sheep). Using a customized SISPA approach and the nanopore sequencing technology we successfully recovered genomic sequences from viral isolates and blood samples from infected animals from EHD and BT outbreaks. Three different viruses were responsible for these outbreaks: EHDV-8, BTV-8 and BTV-4. The EHDV-8 strain detected in France corresponded to the strain circulating in Tunisia, Sardinia and Spain since 2021 and 2022. A new BTV-8 strain of unknown origin, clearly different from the enzootic strain circulating in France since 2015, was responsible of the BT outbreaks in domestic ruminants in 2023 on both mainland France and Corsica. A second BTV, BTV-4, also involved in BT outbreaks in Corsica, corresponded to a BTV-4 strain occasionally detected on Corsica island since 2016, suggesting either a new introduction of this strain or a silent circulation on the field. The exceptional nature of orbivirus epizootics in France in 2023, including new introduction, emergence or incursions, raises numerous questions regarding BTV and EHDV dynamics and epidemiology and stresses out the need to identify factors involved in these emergences.

Dengue virus infection, caused by a single positive-stranded RNA virus from the Flaviviridae family, represents a significant public health challenge in tropical and subtropical regions. This virus has four serotypes (DENV-1, 2, 3, and 4), primarily transmitted by Aedes mosquitoes. Despite extensive research, effective antiviral treatments and vaccines remain elusive due to the viral diversity and the complex mechanisms such as antibody-dependent enhancement (ADE). In the current study, NS1-positive serum samples from dengue cases in Pakistan (2023-2024), were analyzed to determine the predominant serotype and characterize the envelope (E) gene for further exploration of antiviral targets. Out of 100 samples, 63 (63%) tested positive for DENV-2, indicating its predominance during this period, while two samples showed mixed infections with DENV-2 and DENV-3. The envelope gene was successfully amplified using nested PCR, validated through gel electrophoresis and sanger sequencing. Phylogenetic analysis revealed high similarity of the DENV-2 isolates to strains from China and India. Computational modeling of the envelope protein structure identified potential antiviral binding sites and further molecular docking studies suggested that specific antiviral compounds like Arbidol and Quercetin can inhibit early steps in viral infection. Additionally, BepiPred-3.0 predicted several B-cell epitopes, which could be useful for vaccine development. These findings enhance our understanding of dengue epidemiology in Pakistan and contribute to the development of targeted antiviral therapies, potentially informing future vaccination strategies and outbreak management.

Zinc finger proteins (ZFPs) play an important role in the host-virus interplay. Zinc finger protein 36 is a member of the zinc finger protein 36 family, which includes two other paralogs, namely ZFP36L1 and ZFP36L2. Studies have demonstrated that ZFP36L1 acts as a host defender against influenza A virus and flaviviruses. However, the role of ZFP36 in host-virus interactions has not been thoroughly investigated. Here, we demonstrated that human zinc finger protein 36 (hZFP36) exhibited potent pro-viral activity during Senecavirus A infection. Overexpression of ZFP36 facilitated Senecavirus A infection, while hZFP36 knockdown inhibited viral replication. The ZF motifs of hZFP36 are key for promoting viral proliferation. hZFP36 stabilized Senecavirus A VP1 by binding to it. Furthermore, hZFP36 inhibited SeV-mediated IFN-β production through inducing caspase-dependent cleavage for MAVS. These findings provide insights into the mechanism of action of ZFP36 in host-virus interactions.

Porcine respiratory coronavirus (PRCV) typically causes subclinical or mild respiratory infections in pigs, but may lead to more severe disease with other factors. PRCV infection in Denmark was initially detected in 1984, but data are lacking about its current prevalence and diversity. Antibodies against PRCV were detected in about 75 % of recent pig sera from Denmark. In addition, pig nasal swab samples were screened for PRCV and 12 other respiratory pathogens using a high-throughput RT-qPCR system. All targeted pathogens were detected but at different prevalences. Significant associations were found between the presence of PRCV and certain other pathogens. From PRCV positive samples, partial spike gene sequences and complete nucleocapsid coding sequences were determined. In phylogenetic analyses, these PRCVs clustered with earlier European PRCVs and were distinct from transmissible gastroenteritis virus. We conclude that PRCV is widespread within the pig population in Denmark. Further studies on the significance of PRCV are warranted.

Porcine epidemic diarrhea virus (PEDV) is a highly contagious virus that poses a serious threat to the global pig industry. Despite extensive efforts, the mechanism underlying virus entry for PEDV remains elusive. In this study, we first identified PEDV-susceptible and non-susceptible cell lines by using PEDV spike pseudotyped vesicular stomatitis virus. Subsequently, we conducted a comprehensive transcriptomic analysis on these cell lines. Through integrating differential expression gene analysis with weighted gene co-expression network analysis, we identified the key pathways that are correlated with the PEDV entry. Our analysis revealed a strong correlation between cholesterol, sterols, and lipid transport with PEDV entry, suggesting a potential role for cholesterol transport in the PEDV entry. For further investigation, we treated Huh7, Vero and LLC-PK1 cells with a cholesterol transport inhibitor, ezetimibe, and observed a significant inhibition of PEDV entry and subsequent viral replication in these cells. Interestingly, pre-treating Huh7 cells with ezetimibe resulted in an increase in the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Middle East respiratory syndrome coronavirus (MERS-CoV) pseudoviruses. Moreover, we found that cholesterol could facilitate the entry of PEDV into Huh7 and Vero cells, and this promoting effect can be blocked by ezetimibe. These findings suggest that targeting cholesterol transport specifically inhibits PEDV entry into susceptible cells. Our study offers novel insights into the mechanism of PEDV entry and the development of new therapeutic strategies against this economically important virus.

Rotavirus A (RVA) is one of the major viral causes of acute gastroenteritis in calves globally. Bovine RVA can represent a public health concern as it is capable of zoonotic transmission. We assessed the burden, genotype distribution, and zoonotic potential of RVA among calves in Amhara National Regional State, Ethiopia. A multi-center cross-sectional study was conducted involving a total of 266 calves. Clinical data and fecal samples were collected by trained veterinarians. Total RNA was extracted using QIAamp viral RNA mini kit and RVA was detected by One-step qRT-PCR. Amplification and Sanger sequencing of VP7 and VP4 genes were performed to determine G-types and P-types of the circulating RVA, respectively. The prevalence of RVA among calves was 41/266 (15.4 %, 95 % CI = 11.3 %-19.5 %). The circulating G-types were G6, G8, and G10, while the circulating P-types were P[1], P[4], P[8], P[11], P[13] and P[14]. G10P[11] (37.5 %) followed by G6P[14] (18.8 %), and G6P[1] (12.5 %) were the dominant G/P combinations circulating among calves in the study area. The circulating bovine RVA strains including human-like bovine (GxP[4] and GxP[8]) and porcine-like bovine (G8P[13]) P-genotypes identified in calves were closely related to RVA strains globally reported from bovine, human, caprine, porcine, and other hosts. Our data reveal that the prevalence of RVA in calves is significant with diverse genotypes circulating in the study area with a potential for zoonosis and/or reverse zoonosis. Hence, continuous surveillance of the circulating RVA genotypes is crucial to curb the RVA-associated morbidity and mortality in cattle and human populations.

Criniviruses are emerging pathogens responsible for significant disease outbreaks worldwide. Among them, blackberry yellow vein-associated virus (BYVaV) is prevalent in blackberry-producing areas of the United States and, when present in the blackberry yellow vein disease complex with other viruses, can lead to substantial crop losses. To better understand BYVaV biology and its role in virus complex disease development, we developed a BYVaV-derived infectious clone and a virus-induced gene silencing (VIGS) vector. The infectious clone successfully induced systemic infection and symptom development in Nicotiana benthamiana. Additionally, transmission of the recombinant virus to indicator plants was confirmed using the whitefly vector Trialeurodes vaporariorum. The infectious clone was subsequently modified into a VIGS vector, with the foreign insert remaining stable for the length of the study. This work provides essential tools for advancing the study of BYVaV biology and conducting genomic studies in its natural hosts.

From 1988-2023, Pará accounted for the highest proportion of deforestation among all states in the Brazilian Amazon. Specifically, 57.20 % of the territory in the Santa Bárbara municipality was deforested as of 2023. Since 2017, the Hantaviridae family has included viruses identified in nonrodent vertebrates, such as mobatviruses (from moles and bats). In the current metagenomic analysis of a pool of multiple organs of a Carollia brevicauda bat, we obtained sequences for three segments of the previously described Buritiense virus (BURV); to date, only the L segment had been sequenced for this mobatvirus. This study provides the first description of BURV in the Amazon region and provides information on the S and M segments of the virus. These findings corroborate the presence of BURV in Brazil in an area far from the site of the first detection and in another bat species.

Zika virus (ZIKV), a Flaviviridae family member, has been linked to severe neurological disorders. Despite detailed studies on recent outbreaks, the early evolutionary history of ZIKV remains partially unclear. This study elucidates ZIKV origin and evolutionary dynamics, focusing on recombination events, early lineage diversification, and virus spread across continents.

Porcine epidemic diarrhea virus (PEDV) is a harmful coronavirus infecting pigs, which is resulting in substantial financial losses in the global pig industry. The lack of effective vaccines or treatments underscores the pressing need for new antiviral strategies. Antimicrobial peptides (AMPs), specifically cathelicidins such as LL-37, have demonstrated promising activity against a range of viruses. This study aims to elucidate the antiviral mechanisms of cathelicidins by examining their inhibitory capabilities against PEDV in vitro. Four pig-derived antimicrobial peptides (PMAP-36, PMAP-23, PR-39, and PG-1), together with chicken-derived CATH-B1 and human-derived LL-37 were analyzed for their anti-PEDV activity. Flow cytometry and fluorescent microscopy confirmed that LL-37 and CATH-B1 had strong inhibitory effects at non-toxic concentrations of 5 and 10 µM, significantly reducing GFP-PEDV infection of Vero cells both in co- and pre-incubation setups. In contrast, none of the porcine peptides exhibited any inhibitory effects, even at higher doses. Fluorogenic LL-37 was shown to enter VERO cells, indicative of a possible immunomodulatory antiviral mode of action. However, transmission electron microscopy clearly indicated that both LL-37 and CATH-B1 affected virus morphology and caused aggregation of viral particles, showing that peptide-virus interaction caused reduced virus infectivity. In conclusion, this analysis highlights the potential of LL-37 and CATH-B1 as inhibitors against PEDV, suggesting promising directions for innovative therapeutic antiviral strategies.

The Yellow Fever virus (YFV) wild-type strains studied until now have little or no ability to evade the Syrian hamster interferon antiviral response. Thus, evaluating the susceptibility of this model to new YFV isolates is paramount to aid in the understanding of their viscerotropic phenotype. To this end, Syrian hamsters were inoculated intraperitoneally with two Brazilian wild-type YFV isolates originated from dying or dead howler monkeys obtained during outbreaks in the states of Rio Grande do Sul in 2008 (PR4408) and Rio de Janeiro in 2019 (RJ155). The results were compared with a YFV experimental vaccine strain (17DD). The main findings observed for animals infected with the PR4408 strain were progressive weight loss and persistent viremia (at least up to day seven post-infection), associated with viral RNA detection in the liver, and hepatic, splenic, and pancreatic histological alterations consistent with YF. The infection was eliminated seven days post-infection in animals inoculated with the RJ155 strain. No changes were observed for animals infected with 17DD virus. The findings indicate that both Brazilian isolates are able to infect Syrian hamsters, resulting in histopathological changes compatible with the YF pathology observed in humans. Furthermore, the PR4408 strain exhibited increased virulence in this mammalian model, despite causing a non-fatal infection.

Norovirus, belonging to the Caliciviridae family, is a non-enveloped, positive-sense single-stranded RNA virus. It is widely acknowledged as a significant etiological agent responsible for non-bacterial acute gastroenteritis and considered a major cause thereof. Norovirus is primarily tranmitted via fecal-oral route, but can also be transmitted via airborne routes. Clinical manifestations often include symptoms associated with acute gastroenteritis, like nausea, vomiting, watery diarrhea, stomach cramps, and others. Due to the specific pathogenic mechanism of the virus, and genomic diversity, there are currently no preventive vaccines or effective antiviral drugs available for treating norovirus-induced acute gastroenteritis infections. The management of such infections mainly relies on oral rehydration therapy while prevention necessitates adherence to personal hygiene measures. The present paper discusses the nature, transmission route, clinical manifestations, immune response mechanism, and vaccine research of Norovirus. The objective of this review manuscript is to systematically gather, analyze, and summarize recent research and investigations on norovirus in order to enhance our understanding of its characteristics and pathogenesis. This not only facilitates subsequent researchers in acquiring a more expedited and comprehensive grasp of the existing knowledge about norovirus but also provides clearer directions and goals for future studies.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) pandemic, posing serious threats to global health. Effective broad-spectrum antiviral drugs for the treatment of COVID-19 are not sufficiently available. In the present study, we investigated the antiviral activity of the natural lignan diphyllin (PubChem CID 100492) against different SARS-CoV-2 variants and explored the underlying molecular mechanisms. We found that diphyllin dose-dependently inhibits the SARS-CoV-2 spike (S)-mediated entry into different types of cells. The potent inhibition was evident against spike proteins derived from the original SARS-CoV-2 and from variants of concern such as Alpha, Beta, Delta or Omicron. Accordingly, diphyllin also significantly inhibited the in vitro infection of a clinical SARS-CoV-2 virus isolate. Mechanistically, diphyllin simultaneously inhibited the endosomal entry of SARS-CoV-2 by neutralizing the endosomal acidification and reducing the activity of the cysteine protease cathepsin L (CTSL) as well as S-meditated cell surface entry by impairing furin activity. Collectively, our findings establish diphyllin as novel inhibitor of CTSL and furin proteases, resulting in a double-pronged attack on SARS-CoV-2 entry along endosomal as well as cell surface routes. Therefore, diphyllin has the potential to be advanced as an inhibitor of SARS-CoV-2 entry.

New and emerging viral problems may be contributing to blueberry decline. In this research we described a new virus detected in Oregon blueberry production field and surveyed the region for its potential spread. The complete genome sequence of a putative new member of the genus Luteovirus was obtained from blueberry (Vaccinium corymbosum L.) by high throughput sequencing and 5'/3'-RACE. The new virus was tentatively named blueberry virus M (BlVM). Its genome is 5,018 nt long with four putative open reading frames. Similarly to some recently discovered luteoviruses, BlVM does not possess any movement protein (MP). Phylogenetic analysis confirmed clustering of BlVM with the group of non-MP luteoviruses, showing blueberry virus L as the most similar species. Through a small-scale high throughput sequencing survey we obtained 14 additional near complete genomic sequences. A larger survey of 2,654 samples by RT-PCR in Oregon and Washington (USA) found 52 BlVM-positive plants collected from four locations in Oregon. These findings will facilitate monitoring virus distribution and assessment of potential disease associated with this new and emerging blueberry virus.