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Results for “Virus Replication”

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At least 19 recordsLinked to original sources

PubMed2026

EIF4H and YBX1 are essential host factors for hepatitis E virus replication and pathogenesis.

Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis worldwide, responsible for approximately 20 million infections annually. Despite the availability of a vaccine in China, no direct-acting antivirals are approved, and host factors required for HEV replication remain poorly defined. Here, using a genome-wide CRISPR/Cas9 knockout screen in a replicon system, we identified Eukaryotic Translation Initiation Factor 4H (EIF4H) and Y-Box Binding Protein 1 (YBX1) as essential host factors for HEV replication and pathogenesis. Knockout of either factor markedly impaired replication of HEV genotypes 1, 3, and 4, as well as HEV infection and production in hepatocellular carcinoma cells and human induced pluripotent stem cell-derived hepatocyte-like cells, while leaving SARS-CoV-2, hepatitis B virus, hepatitis C virus, and Zika virus unaffected, underscoring their HEV-specific roles. Mechanistically, EIF4H interacts with ORF1 via its methyltransferase-Y-papain-like protease region, and EIF4H deficiency alters the composition of the ORF1-associated replication complex. By contrast, YBX1 is dispensable for ORF1 translation and RNA binding but is specifically required for ORF1 proteolytic processing, a prerequisite for assembling a functional replication machinery. EIF4H knockout rats and liver-specific YBX1 knockout rats were largely resistant to rat HEV-C1 infection, showing profound reductions in viral shedding, suppressed hepatic and intestinal viral loads, and protection from liver pathology. Together, our findings establish EIF4H and YBX1 as essential host factors for HEV infection and pathogenesis and reveal potential targets for antiviral intervention.

Virus Replication↗

PubMed2026

MARK1 suppresses infectious bursal disease virus replication via phosphorylating VP3.

Infectious bursal disease virus (IBDV) of the Birnaviridae family is a non-envelope, double-stranded RNA virus that encodes a VP3 protein with multiple functions, which controls viral genome replication, IFN-β production, and virus traffic in infected cells. Posttranslational modifications (PTMs), such as ubiquitination, of VP3 have been demonstrated for affecting its function and stability. To clarify the mechanism by which VP3 is regulated in IBDV infected cells, we focused on the phosphorylation of VP3. Mass spectrometry analysis identified that microtubule-affinity regulating kinases 1 (MARK1) was a kinase interacting protein of VP3. Inhibitory function of MARK1 in affecting viral replication was validated. We describe the phosphorylation event at the serine 130 (S130) and serine 163 (S163) residues of VP3 mediated by MARK1 via mass spectrometry analysis. Alanine replacement of the phosphorylation sites in VP3 significantly enhanced its RNA-binding activity. Additionally, the mutation of two serine residues led to remarkably improved in its polymerase-enhancing function. We then incorporated the two mutations to rescue recombinant IBDV. Viral growth curve analysis revealed that replication of mutant IBDV was significantly enhanced relative to wild type (WT) virus. In conclusion, we found that VP3 functions are specifically regulated by MARK1 mediated phosphorylation at S130 and S163 and that this regulation suppresses IBDV replication ultimately.

Infectious bursal disease virus↗

PubMed2026

PRMT3 restricts porcine epidemic diarrhea virus replication by disrupting the interaction between VAPA and the viral nucleocapsid protein.

Porcine epidemic diarrhea virus (PEDV) represents a severe threat to the global swine industry. Its infection process involves intricate virus-host interactions and immune evasion mechanisms, but effective therapeutic targets remain elusive. In this study, we identified protein arginine methyltransferase 3 (PRMT3) as a novel regulatory factor that significantly modulates PEDV infection via genome-wide CRISPR/Cas9 knockout library screening. Knockout or inhibition of PRMT3 markedly enhanced PEDV infection in multiple cell lines, including LLC-PK1, IPEC-J2, and primary porcine intestinal epithelial cells. Mechanistic investigations revealed that PRMT3 can restrict PEDV infection by interacting with vesicle-associated membrane protein-associated protein A (VAPA). Further analysis revealed that VAPA facilitates cholesterol transport through binding to oxysterol-binding protein (OSBP) and inhibits the autophagic degradation of the viral nucleocapsid (N) protein, with both processes being critical for promoting PEDV infection in host cells. A detailed analysis revealed that K52 within its major sperm protein (MSP) domain interacts with D404 and D405 in the two phenylalanines in an acidic tract (FFAT)-like motifs of the N protein, and these interactions proved essential for PEDV infection. In summary, this is the first study to identify and validate the PRMT3-VAPA-N protein autophagic degradation axis as a key pathway through which PRMT3 suppresses PEDV infection, with VAPA acting as an essential host factor for PEDV pathogenesis. These findings uncover novel signaling pathways and molecular targets for the development of anti-PEDV therapeutics.

Animals↗

PubMed2026

Transcriptomic and Metabolomic Profiling Identifies a Core Gene-Metabolite Axis Driving African Swine Fever Virus Replication in the Soft Tick Ornithodoros lahorensis.

African swine fever virus (ASFV) causes an incurable swine disease with nearly 100% mortality, posing a catastrophic threat to global pig production. The soft tick Ornithodoros lahorensis acts as a critical biological vector that sustains persistent ASFV replication and mediates long-distance viral transmission, yet the molecular mechanisms governing ASFV-tick interplay remain poorly understood. Here, we integrated transcriptomics and metabolomics to systematically dissect molecular changes in O. lahorensis across three infection stages: Uninfected control, early infection (7 days post-infection, dpi), and late persistent infection (21 dpi). Multi-omics integration revealed that ASFV extensively remodels tick host metabolism, predominantly activating purine/pyrimidine metabolism, lipid biosynthesis, and energy metabolism. We further characterized a conserved regulatory module consisting of 12 core genes and 8 signature metabolites that collectively support ASFV genome replication and virion assembly. Three hub metabolic genes (TK1, ATP5F1B, and IMPDH) were selected for functional validation via siRNA silencing in ticks; individual gene silencing suppressed ASFV loads by 89.2%, 91.5%, and 87.8%, respectively (p < 0.001***). This work represents the first comprehensive multi-omics investigation of ASFV infection in O. lahorensis. We identified tick-specific molecular targets to block vector-mediated ASFV spread and established a standardized multi-omics analytical pipeline for tick-virus interaction research. Our findings elucidate the mechanistic basis of long-term ASFV persistence in soft ticks and deliver novel actionable clues for developing vector-targeted ASF intervention strategies.

Animals↗

PubMed2025

Viral hijacking of host DDX60 promotes Crimean-Congo haemorrhagic fever virus replication via G-quadruplex unwinding.

Crimean-Congo haemorrhagic fever virus (CCHFV) is the most prevalent tick-borne zoonotic bunyavirus, causing severe hemorrhagic fever and fatality in humans. Currently, the absence of approved vaccines or therapeutics for CCHFV infection necessitates the development of innovative therapeutic strategies. Here, we identify a guanine (G)-rich sequence located within the mRNA of the glycoprotein precursor in the medium (M) segment of the CCHFV genome, designated as M-PQS-1664(+). M-PQS-1664(+) can form stable G-quadruplex (G4) structure and functions as a negative regulatory element for viral replication. Host DDX60 is up-regulated in response to CCHFV infection, thereby it is hijacked to unwind M-PQS-1664(+) G4 for facilitating viral replication. The FDA-approved drug Cepharanthine (CEP), which competes with DDX60 to specifically stabilize M-PQS-1664(+) G4 without a global induction of host cellular G4s formation, exhibits remarkable antiviral activity in vitro and in vivo. More importantly, CEP possesses antiviral activity (50% inhibitory concentration ~ 0.2 μM) that having ~ 88 × the potency of ribavirin. Our findings underscore the CCHFV G4s as a promising target for drug development and highlight the significant potential of CEP in combating CCHFV.

Hemorrhagic Fever Virus, Crimean-Congo↗

PubMed2025

Hepatocyte-Enriched miRNA-193b-3p Promotes Hepatitis B Virus Replication by Dual Activation of Viral Core Promoter Activity and Autophagy Induction by Targeting IGF-1R.

Hepatitis B virus (HBV) infection is a principal cause of severe liver disease in humans and is associated with increased levels of specific serum or intracellular microRNAs (miRNAs). Among these, miR-193b-3p is a liver-enriched miRNA; however, its role in HBV replication remains unknown. This study aimed to investigate the influence of chronic HBV infection on miR-193b-3p levels in the peripheral blood and liver tissues of patients with chronic hepatitis B (CHB), evaluate the effect of miR-193b-3p on HBV replication both in vitro and in vivo, and elucidate the potential underlying mechanisms. We showed that hepatic miR-193b-3p levels in patients with CHB were significantly elevated compared with those in healthy controls. Ectopic expression of miR-193b-3p significantly enhanced HBV replication and transcription in different hepatoma cell lines. Furthermore, we identified IGF-1R as a direct target through which miR-193b-3p regulates HBV replication. Mechanistically, miR-193b-3p increased HBV core promoter activity via the IGF-1R/FXRα axis, thereby enhancing HBV transcription. Additionally, miR-193b-3p increased IGF-1R/Akt/MDM2/p53 signaling-mediated autophagy induction, which in turn facilitated increased HBV post-transcriptional activity. Collectively, hepatocyte-enriched miR-193b-3p exerts a proviral effect on HBV replication through dual synergistic mechanisms, offering novel insights into its role in HBV replication and potential therapeutic implications in CHB infection.

Humans↗

PubMed2026

The Differential Effects of Immunosuppressants on Hepatitis E Virus Replication and the Triggered Inflammatory Responses in Macrophages.

Organ transplant recipients are at high risk of developing chronic infection when exposed to hepatitis E virus (HEV), which can rapidly progress to liver fibrosis and cirrhosis. Macrophages play a key role in the response to the infection and disease progression. However, the interactions amongst immunosuppressants, macrophages, the course of HEV infection and activation of inflammatory response remain unclear. In this study, we generated M0, M1 and M2 macrophages from the human THP-1 cell line. These macrophages were then infected with HEV and treated with different immunosuppressants. We visualised viral infection using laser confocal microscopy, and quantitatively analysed viral replication and inflammatory responses by bulk sequencing, RT-qPCR, ELISA and Western blotting. We found that the M1 inflammatory macrophages exhibited the highest, while M2 macrophages had the lowest levels of viral RNA. Genome-wide transcriptome analysis indicated that viral, inflammation and immunity-related pathways were predominantly upregulated by HEV infection. Dexamethasone exerted potent inhibitory effects on inflammatory response in macrophages. Mycophenolic acid (MPA) demonstrated inhibitory effects on viral replication, IL-1β and TNF-α expression, whereas mTOR inhibitors had the opposite effects, and tacrolimus showed no clear effect. In conclusion, immunosuppressants can differentially affect HEV replication and the subsequent inflammatory responses in macrophages.

Humans↗

PubMed2025

Dengue Virus Replicative-Form dsRNA Is Recognized by Both RIG-I and MDA5 to Activate Innate Immunity.

RIG-I like receptors (RLRs) are a family of cytosolic RNA sensors that sense RNA virus infection to activate innate immune response. It is generally believed that different RNA viruses are recognized by either RIG-I or MDA5, two important RLR members, depending on the nature of pathogen-associated molecular patterns (PAMPs) that are generated by RNA virus replication. Dengue virus (DENV) is an important RNA virus causing serious human diseases. Despite extensive investigations, the molecular basis of the DENV PAMP recognized by the host RLR has been poorly defined. Here, we demonstrated that the DENV infection-induced interferon response is dependent upon both RIG-I and MDA5, with RIG-I playing a predominant role. Next we purified the DENV PAMP RNA from the DENV-infected cells, and demonstrated that the purified DENV PAMP is viral full-length double-stranded RNA bearing 5'ppp modifications, likely representing the viral replicative-form RNA. Finally, we confirmed the nature of the DENV PAMP by reconstituting the viral replicative-form RNA from in vitro synthesized DENV genomic RNA. In conclusion, our work not only defined the molecular basis of the RLR-PAMP interaction during DENV infection, but also revealed the previously underappreciated recognition of a distinct moiety of the same PAMP by different RLRs in innate immunity against RNA viruses.

Interferon-Induced Helicase, IFIH1↗

PubMed2026

Acrocomia aculeata (Mbokaja) Kernel Oil Inhibits Herpes Simplex Virus 1 Replication and Promotes Cutaneous Wound Healing in Infected Mice.

Background/Objectives: Herpes simplex virus type 1 (HSV-1) is a global and prevalent pathogen, presenting significant clinical challenges because of its recurring infections, the development of drug resistance and severe clinical complications. This study evaluated the antiviral efficacy against HSV-1 of Acrocomia aculeata (A. aculeata) kernel oil, a Neotropical palm native to the Americas. Methods: The chemical profile of A. aculeata kernel oil was determined by gas chromatography with flame ionization detection (GC-FID). Antiviral activity was assessed using dose-response curves, time-of-addition assays, and quantification of intracellular viral genomes, viral gene transcripts, and IL-6 expression. A. aculeata kernel oil's antiviral effect was also evaluated using an in vivo HSV-1 cutaneous infection model. Results: GC-FID analysis revealed lauric, oleic, and myristic acids as predominant components in the kernel oil. A. aculeata kernel oil exhibited potent antiviral activity against HSV-1. The oil inhibited HSV-1 early step post-entry, reducing the mRNA levels of the immediate-early genes ICP4 and ICP22, leading to the downregulation of early and late viral gene expression and intracellular viral genome. Furthermore, the oil suppressed IL-6 expression in infected cells. Importantly, A. aculeata kernel oil promoted the healing of cutaneous lesions in HSV-1-infected mice. Conclusions: These findings demonstrate that A. aculeata kernel oil is a promising candidate for developing novel antiviral and topical therapies against HSV-1.

Animals↗

PubMed2025

Argonaute 2 targets viral transcripts but not genomes of RNA viruses during antiviral RNA interference in Drosophila.

RNA interference (RNAi) mediated by the small interfering RNA (siRNA) pathway is a major antiviral mechanism in insects. This pathway is triggered when double-stranded RNA (dsRNA) produced during virus replication is recognized by Dicer-2, leading to the formation of virus-derived siRNA duplexes. These siRNAs are loaded onto the programmable nuclease Argonaute-2 (AGO2), with one strand serving as a guide to target and cleave fully complementary sequences of viral RNAs. While siRNAs are generated from viral dsRNA, the specific viral RNA species targeted for silencing during RNA virus replication remains unclear. In this study, we characterized the primary viral RNA targets of the Drosophila siRNA pathway during infections caused by negative and positive RNA viruses, namely Vesicular stomatitis virus (VSV) and Sindbis virus (SINV). Our findings reveal that polyadenylated transcripts of VSV and SINV are the major targets of silencing by the siRNA pathway during infection, likely when they are poised for translation. Consistent with earlier findings, we show that AGO2 is associated with ribosomes in control and virus infected cells. Therefore, we propose that the inhibition of the replication of RNA viruses in Drosophila results from the silencing of incoming viral transcripts, facilitated by the association of AGO2 with ribosomes.

Animals↗

PubMed2024

Human parainfluenza virus 3 vaccine candidates attenuated by codon-pair deoptimization are immunogenic and protective in hamsters.

Human parainfluenza virus type 3 (HPIV3) is a major pediatric respiratory pathogen lacking available vaccines or antiviral drugs. We generated live-attenuated HPIV3 vaccine candidates by codon-pair deoptimization (CPD). HPIV3 open reading frames (ORFs) encoding the nucleoprotein (N), phosphoprotein (P), matrix (M), fusion (F), hemagglutinin-neuraminidase (HN), and polymerase (L) were modified singly or in combination to generate 12 viruses designated Min-N, Min-P, Min-M, Min-FHN, Min-L, Min-NP, Min-NPM, Min-NPL, Min-PM, Min-PFHN, Min-MFHN, and Min-PMFHN. CPD of N or L severely reduced growth in vitro and was not further evaluated. CPD of P or M was associated with increased and decreased interferon (IFN) response in vitro, respectively, but had little effect on virus replication. In Vero cells, CPD of F and HN delayed virus replication, but final titers were comparable to wild-type (wt) HPIV3. In human lung epithelial A549 cells, CPD F and HN induced a stronger IFN response, viral titers were reduced 100-fold, and the expression of F and HN proteins was significantly reduced without affecting N or P or the relative packaging of proteins into virions. Following intranasal infection in hamsters, replication in the nasal turbinates and lungs tended to be the most reduced for viruses bearing CPD F and HN, with maximum reductions of approximately 10-fold. Despite decreased in vivo replication (and lower expression of CPD F and HN in vitro), all viruses induced titers of serum HPIV3-neutralizing antibodies similar to wt and provided complete protection against HPIV3 challenge. In summary, CPD of HPIV3 yielded promising vaccine candidates suitable for further development.

Animals↗

PubMed2025

A Quantitative Real-Time PCR Assay for Measuring Poxvirus Replication and Cell Binding.

Quantitative real-time PCR (qPCR) is a fast and reliable method to quantify viral genomes as a surrogate to titering on monolayers of cells for measuring virus replication. Whether it be for determining the number of virions released, the total number of genomes produced during infection, or the number of virions bound to a cell, qPCR assays can be adapted to quickly enumerate total viral genomes in a broad range of experiments comparing virus replication under different conditions. In addition, qPCR offers several advantages compared to plaque assays including time, linearity over 9 logs, and scalability from tens-to-hundreds of samples, depending on the qPCR machine. Here we describe a qPCR assay for quantifying vaccinia virus' dsDNA genome that can be used to determine the total number of virions produced. Furthermore, we describe a straightforward protocol for a cell-binding assay that is sensitive enough to use with small concentrations of inoculating virions. This protocol is suitable for measuring the cell-binding ability of mutations that affect virus production and infectivity.

Virus Replication↗

PubMed2025

Proximity interactome of alphavirus replicase component nsP3 includes proviral host factors eIF4G and AHNAK.

All positive-strand RNA viruses replicate their genomes in association with modified intracellular membranes, inducing either membrane invaginations termed spherules, or double-membrane vesicles. Alphaviruses encode four non-structural proteins nsP1-nsP4, all of which are essential for RNA replication and spherule formation. To understand the host factors associated with the replication complex, we fused the efficient biotin ligase miniTurbo with Semliki Forest virus (SFV) nsP3, which is located on the cytoplasmic surface of the spherules. We characterized the proximal proteome of nsP3 in three cell lines, including cells unable to form stress granules, and identified >300 host proteins constituting the microenvironment of nsP3. These included all the nsPs, as well as several previously characterized nsP3 binding proteins. However, the majority of the identified interactors had no previously identified roles in alphavirus replication, including 39 of the top 50 interacting proteins. The most prominent biological processes involving the proximal proteins were nucleic acid metabolism, translational regulation, cytoskeletal rearrangement and membrane remodeling. siRNA silencing confirmed six novel proviral factors, USP10, AHNAK, eIF4G1, SH3GL1, XAB2 and ANKRD17, which are associated with distinct cellular functions. All of these except SH3GL1 were also important for the replication of chikungunya virus. We discovered that the small molecule 4E1RCat, which inhibits the interaction between the canonical translation initiation factors eIF4G and eIF4E, exhibits antiviral activity against SFV. Since the same molecule was previously found to inhibit coronaviruses, this suggest the possibility that translation initiation factors could be considered as targets for broadly acting antivirals.

Viral Nonstructural Proteins↗

PubMed2025

Transcription- and Replication-Competent Virus-like Particle Systems for Marburg Virus.

Here, we describe the transcription- and replication-competent virus-like particle (trVLP) system for Marburg virus (MARV), which recapitulates transcription and replication of the viral genome in addition to viral particle assembly, egress, and entry. This protocol includes instructions for transfections for producer and acceptor cells and the use of trVLPs for infection.

Marburgvirus↗

PubMed2026

Bergamottin, a bioactive component of bergamot: dual inhibition of Japanese encephalitis virus internalization and genome replication.

Japanese encephalitis virus (JEV) is associated with high mortality and severe neurological sequelae, and existing prevention and control strategies remain insufficient. Therefore, the development of novel antiviral agents is of critical public health importance. This study systematically evaluated the antiviral activity and underlying mechanism of bergamottin, a natural product. Bergamottin exhibited significant dose-dependent inhibitory effects against JEV in multiple cell lines, including BHK-21, HuH-7, and Vero cells, demonstrating potent antiviral efficacy. Mechanistic investigations revealed that bergamottin primarily targeted the internalization and replication stages of the JEV life cycle, thereby effectively suppressing viral proliferation. Additionally, adaptive mutation screening indicated that the D389G mutation in envelope protein E confers drug resistance by potentially changing E protein conformation or reducing endocytic efficiency. In vivo experiment, bergamottin significantly reduced viral loads in mouse brain tissue and effectively improved the survival rate of infected mice. Our findings indicated that bergamottin exerted antiviral activity by dual targeting of key steps in the viral life cycle, making it a highly promising candidate for anti-JEV therapy. Further exploration of the antiviral properties of bergamottin is expected to facilitate its clinical development as a treatment for JEV infection.

Animals↗

PubMed2025

Spatiotemporal profile of an optimal host response to virus infection in the primate central nervous system.

Viral infections of the central nervous system (CNS) are a major cause of morbidity largely due to lack of prevention and inadequate treatments. While mortality from viral CNS infections is significant, nearly two thirds of the patients survive. Thus, it is important to understand how the human CNS can successfully control virus infection and recover. Since it is not possible to study the human CNS throughout the course of viral infection at the cellular level, here we analyzed a non-lethal viral infection in the CNS of nonhuman primates (NHPs). We inoculated NHPs intracerebrally with a high dose of La Crosse virus (LACV), a bunyavirus that can infect neurons and cause encephalitis primarily in children, but with a very low (≤ 1%) mortality rate. To profile the CNS response to LACV infection, we used an integrative approach that was based on comprehensive analyses of (i) spatiotemporal dynamics of virus replication, (ii) identification of types of infected neurons, (iii) spatiotemporal transcriptomics, and (iv) morphological and functional changes in CNS intrinsic and extrinsic cells. We identified the location, timing, and functional repertoire of optimal transcriptional and translational regulation of the primate CNS in response to virus infection of neurons. These CNS responses involved a well-coordinated spatiotemporal interplay between astrocytes, lymphocytes, microglia, and CNS-border macrophages. Our findings suggest a multifaceted program governing an optimal CNS response to virus infection with specific events coordinated in space and time. This allowed the CNS to successfully control the infection by rapidly clearing the virus from infected neurons, mitigate damage to neurophysiology, activate and terminate immune responses in a timely manner, resolve inflammation, restore homeostasis, and initiate tissue repair. An increased understanding of these processes may provide new therapeutic opportunities to improve outcomes of viral CNS diseases in humans.

Animals↗

PubMed2024

TMPRSS2-mediated SARS-CoV-2 uptake boosts innate immune activation, enhances cytopathology, and drives convergent virus evolution.

The accessory protease transmembrane protease serine 2 (TMPRSS2) enhances severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uptake into ACE2-expressing cells, although how increased entry impacts downstream viral and host processes remains unclear. To investigate this in more detail, we performed infection assays in engineered cells promoting ACE2-mediated entry with and without TMPRSS2 coexpression. Electron microscopy and inhibitor experiments indicated TMPRSS2-mediated cell entry was associated with increased virion internalization into endosomes, and partially dependent upon clathrin-mediated endocytosis. TMPRSS2 increased panvariant uptake efficiency and enhanced early rates of virus replication, transcription, and secretion, with variant-specific profiles observed. On the host side, transcriptional profiling confirmed the magnitude of infection-induced antiviral and proinflammatory responses were linked to uptake efficiency, with TMPRSS2-assisted entry boosting early antiviral responses. In addition, TMPRSS2-enhanced infections increased rates of cytopathology, apoptosis, and necrosis and modulated virus secretion kinetics in a variant-specific manner. On the virus side, convergent signatures of cell-uptake-dependent innate immune induction were recorded in viral genomes, manifesting as switches in dominant coupled Nsp3 residues whose frequencies were correlated to the magnitude of the cellular response to infection. Experimentally, we demonstrated that selected Nsp3 mutations conferred enhanced interferon antagonism. More broadly, we show that TMPRSS2 orthologues from evolutionarily diverse mammals facilitate panvariant enhancement of cell uptake. In summary, our study uncovers previously unreported associations, linking cell entry efficiency to innate immune activation kinetics, cell death rates, virus secretion dynamics, and convergent selection of viral mutations. These data expand our understanding of TMPRSS2's role in the SARS-CoV-2 life cycle and confirm its broader significance in zoonotic reservoirs and animal models.

SARS-CoV-2↗

PubMed2025

Tissue tropism, pathology, and pathogenesis of West Nile virus infection in saltwater crocodile (Crocodylus porosus).

West Nile virus (WNV) is one of the leading causes of economic losses to the saltwater crocodile farming industry due to skin lesions, known as "pix", induced by the infection. Our previous study suggested a possible immunopathological pathway causing these lesions. We therefore resolved to investigate the kinetics of WNV-infection and the elicited immune responses in experimentally challenged saltwater crocodile hatchlings. Employing virus isolation, quantitation of viral genome loads in tissues by RT-qPCR and immunohistochemistry, we demonstrated that upon infection, the virus replicates in the spleen, liver and later in the pancreas. Transcriptomic analysis, based on RNA sequencing and RT-qPCR of kidney and liver tissues, revealed that the early host response is primarily via alteration of cellular structure and metabolism. As the infection progresses, the response becomes predominantly inflammatory and antiviral. The results suggest that the kidney and gastrointestinal tract are primary nidi of viral replication leading to cloacal shedding, but a link to skin lesion development remains to be fully clarified.

Animals↗