Search Results (175)

Porcine deltacoronavirus (PDCoV) is an emerging swine enteric coronavirus that causes severe diarrhea in piglets, leading to extensive economic losses in the global swine industry. Previous studies have reported that PDCoV can experimentally infect multiple animal species. However, the replication capability of PDCoV in non-natural host cell lines remains largely unknown. Herein, we investigated the effects of exogenous trypsin on PDCoV replication and systematically evaluated the susceptibility of various cell lines derived from human, murine, and feline to PDCoV. The results showed that highly permissive cell lines (H1299, Caco-2, MC-38) supported efficient viral replication without the requirement for exogenous trypsin, and high concentrations of trypsin induced prominent syncytia formation in infected H1299, U251, and Neuro-2a cells. Furthermore, this study also found that trypsin can enhance PDCoV replication in a concentration-dependent manner in semi-permissive cell lines. PDCoV can replicate in multiple cell lines of human, murine, and feline origin. Human cells (H1299, Caco-2) and murine MC-38 are highly susceptible to PDCoV infection, whereas MCF-7, TE-10, and KYSE-410 cells were completely non-permissive. The results also revealed a potential correlation between basal APN expression and cellular susceptibility to PDCoV. Collectively, this study provides a basis for assessing the interspecies transmission and zoonotic risk of PDCoV. Full article

Feline and canine coronaviruses (FCoVs and CCoVs) are widely prevalent in companion animals. The recent emergence of a highly virulent FCoV-CCoV recombinant virus, FCoV-23, caused a rapid feline infectious peritonitis (FIP) outbreak in Cyprus, which raises a serious concern about the cross-species transmission of CoVs among companion animals. Here, we evaluated the prevalence, transmission and evolution of FCoV and CCoV in the Jiangsu and Zhejiang provinces of China in 2025. A universal RT-qPCR assay for FCoV and CCoV was established and used for the detection of 700 clinical samples, including 501 from cats and 199 from dogs. A total of 92 samples (13.14%, 92/700) were detected as positive, containing 79 positive samples (15.76%, 79/501) from cats and 13 positive samples (6.5%, 13/199) from dogs. Ten complete S genes and two complete genomes were obtained from positive samples. Fragment comparison and phylogenetic analysis identified one CCoV-I sequence from a feline sample and one FCoV-II sequence from a canine sample. Furthermore, recombination analyses not only detected intra-species recombination events but also inter-species cross-over events. Collectively, this study, for the first time, revealed that cross-species transmission and recombination events occurred between FCoV and CCoV among companion animals in the Jiangsu–Zhejiang region of China in 2025. Full article

Feline Infectious Peritonitis (FIP) has been transformed from a fatal disease to a treatable condition following the introduction of GS-441524, a nucleoside analogue targeting feline coronavirus replication. However, the widespread use of unregulated compounded formulations and the absence of validated analytical tools for therapeutic drug monitoring (TDM) represent critical gaps in clinical FIP management. This study describes the development and full ICH M10-compliant validation of a high-throughput LC-MS/MS method for the quantification of GS-441524 in feline serum, incorporating an automated protein precipitation protocol and a PBS-BSA surrogate matrix in accordance with 3Rs principles. The method met all acceptance criteria across validated parameters, including linearity (0.1–50 µg/mL), accuracy (bias within ±12.5%), precision (CV ≤ 10.9%), selectivity, extraction recovery (87.5–107.9%), and stability under clinically relevant storage conditions. Matrix equivalence between PBS-BSA and authentic feline serum was confirmed, enabling routine calibration without animal-derived materials. The validated method was applied to clinical TDM in cats undergoing GS-441524 treatment for FIP, providing preliminary evidence of inter-individual pharmacokinetic variability. The compounded formulations administered to the TDM cohort were independently verified by LC-MS/MS, confirming drug content within ±15% of labelled claims and excluding pharmaceutical quality as a confounding factor in the interpretation of serum drug concentrations. Full article

While viral diseases of domestic cats (Felis catus) can threaten the recovery of the European wildcat (Felis s. silvestris), their epidemiology in wildcat populations remains poorly understood. Here, we analyzed 428 road-killed wildcats from Western and Central Germany for the presence of antibodies/antigens of six feline viruses. The presence of at least one viral antigen or antiviral antibody was detected in 53.3% of the animals. Antibodies against feline parvovirus (FPV) showed the highest seroprevalence (29.2%), while feline leukemia virus (FeLV) antigens were detected in 22.2% of the animals. Antibodies to feline coronavirus (FCoV), feline herpesvirus (FHV) and feline calicivirus (FCV) were detected in 10% or fewer of the wildcats. No antibodies to feline immunodeficiency virus (FIV) were detected. FeLV antigens clustered spatially, with prevalence declining from southwest to northeast, consistent with the geographic expansion of the virus antigens. Seroprevalence of FPV and prevalence of FeLV increased with age, suggesting cumulative exposure, while juvenile males were particularly unlikely to be seropositive for FPV. Proximity to built-up areas did not predict seroprevalence for any virus. FeLV and FPV in particular warrant further investigation as potential threats to wildcat recovery in Germany and highlight the need for longitudinal health monitoring alongside existing conservation efforts. Full article

This study aimed to evaluate the introduction of Protoparvovirus carnivoran1 (feline panleukopenia virus, FPV/canine parvovirus type 2, CPV-2) and feline coronavirus (FCoV) at admission in a public feline shelter, their molecular epidemiology, and potential associated risk factors. For this purpose, rectal swabs collected from a total number of 368 stray and colony cats were analyzed by a set of classical PCR assays for the detection, typing, and sequencing of FPV/CPV-2 (368 cats) and FCoV (198 cats). A statistical analysis (Chi-squared test or Fisher’s exact test) was performed to evaluate the association between FPV/FCoV positive results and associated data. FPV, CPV-2c, and FCoV-I were detected in 25.8%, 0.5%, and 30.8% of the tested cats, respectively. High degrees of nucleotide identity were observed with local, national, and international viral strains previously collected from cats, wild carnivores, and dogs. Presence of FPV was significantly more likely in male cats (p = 0.024; OR = 0.580) and in 6–12-month (p = 0.003; OR = 4.69) or 12–36-month (p = 0.004; OR = 2.4) cats, while presence of FCoV was higher in younger cats (<3 months) and in those showing respiratory signs (p = 0.046; OR = 2.76). Monitoring both viruses and their associated infection risk factors can help reduce the risks of introduction and transmission within feline colonies, veterinary clinics, or hospitals, supporting targeted measures and standards of care. Full article

Feline coronavirus (FCoV) is widespread in multi-cat environments. Although most infections are asymptomatic, FCoV may mutate into a virulent form responsible for feline infectious peritonitis (FIP), a progressive and mostly fatal systemic disease. Controlling FCoV circulation in multi-cat environments is challenging, but desirable for feline health and breeding management. In this study, we evaluated the impact of stepwise management protocols with increasing stringency on viral shedding in 20 catteries across Flanders, Belgium. Each cattery was allocated to one of three eradication protocols: voluntary (n = 10), stimulatory (n = 5) or obligatory (n = 5). Rectal swabs were collected at the start (T0) and twice after implementation (T6m = 6 months, T12m = 12 months) and tested by RT-qPCR. With the voluntary protocol, the proportion of shedders decreased significantly from 78.6% at T0 to 62.4% at T6m and 45.5% at T12m, though all catteries remained positive (minimum one shedder). The stimulatory protocol reduced shedding from 70.5% (T0) to 30.5% at T6m and 12.9% at T12m, with two of five catteries achieving a negative status. The obligatory eradication protocol achieved the most pronounced effect, with the shedding declining from 55.5% at the start to 17.1% at T6m and 2.5% at T12m, and four of five catteries testing negative by T12m. These findings demonstrate that cattery-level FCoV control is feasible, with an effectiveness depending on the stringency of management. At the end, FCoV-negative catteries can sell certified FCoV-negative kittens. Full article

Feline infectious peritonitis virus (FIPV) remains one of the most challenging viral diseases in veterinary medicine, largely owing to the absence of a consistently effective and safe vaccine. Despite widespread feline coronavirus infection, only a subset of infected cats progresses to feline infectious peritonitis, indicating that host immune responses are key determinants of disease outcomes. Accumulating evidence indicates that disease severity is driven not only by viral replication but also by macrophage- and monocyte-centered immune signaling, leading to excessive inflammation and systemic immunopathology in the host. Previous vaccine approaches against FIPV have failed to provide consistent protection and, in some cases, have been associated with enhanced disease. These outcomes suggest that vaccine-induced immune responses that recapitulate pathogenic signaling patterns may exacerbate disease rather than confer protection. In this review, we discuss the current knowledge of immune cell signaling pathways implicated in FIPV infection, including innate sensing through Toll-like receptors, downstream mitogen-activated protein kinases and NF-κB signaling, cytokine production profiles, Fc receptor-associated processes, and intracellular pathways such as autophagy, and how these mechanisms shape vaccine-induced immunity. By integrating insights from immune signaling kinetics, antibody functionality, adjuvant-driven pathway engagement, and platform-specific immune signatures, this review emphasizes the need to reframe FIPV vaccine development strategies that actively shape host immune responses. Rather than maximizing immunogenicity, successful vaccine design is likely to depend on limiting sustained macrophage activation and pro-inflammatory cytokine amplification while supporting antiviral immune functions, thereby reducing the risk of antibody-dependent enhancement and immunopathology. Beyond feline diseases, these considerations provide broader lessons for vaccine design in settings where immune-mediated pathology contributes to disease severity. Full article

In 2023, Cyprus experienced a large-scale epizootic of feline infectious peritonitis (FIP) temporally associated with the emergence of a novel feline coronavirus, FCoV-23. While molecular investigations have elucidated the recombinant origin of FCoV-23, field-based clinical and other epidemiological data from FIP cases reported during the epizootic period were needed to characterize the outbreak better. A prospective study was conducted using a structured 31-item questionnaire embedded in veterinary management software to characterize FIP cases diagnosed during the epizootic period (late 2022–2025). Data were voluntarily submitted by registered veterinarians across Cyprus. Cases were included based on a clinical diagnosis of FIP; virological confirmation of FCoV-23 infection was not required for inclusion. Data from 68 FIP cases reported by 22 clinics (response rate 21.0%) were analyzed. Affected cats were older than typically reported for FIP (mean age 3.9 years; median 3.0; range 0.4–12.9 years; SD 3.41). Most cases were documented in Limassol (51.5%) and Nicosia (25.0%). The most frequently reported clinical signs were non-specific, like anorexia (60.3%) and weight loss (54.4%), while a variety of neurological and mental manifestations were documented in 35.3% of cases. An albumin-to-globulin ratio < 0.8 was observed in 86.8% of tested cats. Antiviral therapy (GS-441524 or molnupiravir) was administered in 92.2% of cases, with reported clinical improvement of 88.9%. These findings demonstrate the value of questionnaire-based surveillance in documenting outbreak-associated FIP patterns. Although individual cases were not uniformly confirmed as FCoV-23 infections, the increased proportion of neurological presentations among FIP cases reported during the epizootic period supports previous molecular evidence suggesting that neurological involvement was associated with FCoV-23 circulation. Full article

Feline infectious peritonitis (FIP) is a disease arising as a result of feline coronavirus infection. It used to be regarded a fatal disease, with euthanasia commonly recommended following diagnosis due to its very poor prognosis. The availability of effective antiviral therapies, particularly nucleoside analogues such as oral GS-441524, has fundamentally changed the outlook for cats with FIP. FIP is now a treatable and frequently curable disease. In these revised guidelines, the European Advisory Board on Cat Diseases (ABCD) presents an update on the treatment of FIP, incorporating the findings of new studies including the range of available treatments (such as GS-441524, remdesivir and molnupiravir (EIDD-2801) and its active metabolite EIDD-1931), which varies globally, as well as suggestions for monitoring and prognostic indicators. Tables are used to present easy-to-find information on antiviral and supportive treatments for cats with FIP. GS-441524 is the most extensively studied antiviral for FIP with treatment success rates often exceeding 90%. Remdesivir is primarily reserved as an injectable antiviral for severely affected cats unable to tolerate oral medication; it is usually replaced by oral medication as soon as, and when, possible. Although 84-day treatment courses have historically been used, emerging evidence suggests that shorter regimens of 42 days can be equally effective. Full article

Feline infectious peritonitis (FIP) is a highly lethal disease caused by feline infectious peritonitis virus (FIPV), which poses significant diagnostic challenges in clinical practice. FIPV is divided into two serotypes (serotype I and serotype II) based on distinct serological responses driven by substantial sequence divergence in the spike (S) protein. Serotype I predominates in Europe and North America, whereas serotype II is more common in Asia. In this study, we developed a triplex reverse transcription quantitative PCR (RT-qPCR) assay for simultaneous detection and serotyping of FIPV. Primers and TaqMan probes were designed to target the conserved nucleocapsid (N) gene and serotype-specific regions within the S gene. After systematic optimization of reaction conditions, the final assay employed an annealing temperature of 64 °C and optimized primer–probe concentrations. The assay exhibited excellent linearity (R² > 0.99 for all targets), with amplification efficiencies ranging from 97.39% to 109.97%. No cross-reactivity was observed with other common feline pathogens, confirming high specificity. The limit of detection was as low as 0.5 copies/µL, and intra-assay repeatability showed coefficients of variation below 2.1%. Clinical validation using 63 feline samples revealed an overall FIPV positivity rate of 21.63%, with serotype II (17.46%) markedly more prevalent than serotype I (3.17%). Collectively, this triplex RT-qPCR assay demonstrates high sensitivity, exceptional specificity, and robust reproducibility, making it a valuable tool for rapid clinical diagnosis through the simultaneous detection of feline coronavirus (FCoV) and serotyping of FIPV. Full article

Feline infectious peritonitis (FIP) is a fatal disease driven by feline coronavirus induced immune dysregulation and excessive inflammatory cytokine production. Immunomodulatory agents capable of rebalancing this response are therefore of increasing interest. Phallus indusiatus (P. indusiatus), an edible mushroom containing diverse bioactive compounds, has previously demonstrated antiviral and anti-inflammatory potential. This study investigated the immunomodulatory effects of P. indusiatus extract on peripheral blood mononuclear cells (PBMCs) from healthy cats and FIP cats and characterized its chemical constituents using liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). PBMCs were isolated from whole blood and FIP fluid. Cytotoxicity screening identified 19 µg/mL as a non-toxic concentration for subsequent assays. Cytokine responses (IL-1β, IFN-γ, and IL-10) were evaluated following LPS stimulation in PBMCs from whole blood and under basal conditions in PBMCs from FIP fluid after treatment with P. indusiatus extract and dexamethasone. LC–MS/MS profiling combined with STITCH analysis was used to identify bioactive metabolites and their predicted molecular targets. PBMCs derived from FIP fluid exhibited markedly elevated IL-1β and IFN-γ, indicating strong baseline immune activation. P. indusiatus significantly reduced IL-1β and IFN-γ in PBMCs from FIP fluid and suppressed LPS-induced IL-1β and IL-10 in whole-blood PBMCs, demonstrating immunomodulatory patterns comparable to dexamethasone. LC–MS/MS analysis identified compounds including adenosine, phenylalanine, tyrosine, cystathionine, arginine, and sialic acid, which were linked to inflammatory signaling. Overall, the extract exhibited context-dependent modulation of pro- and anti-inflammatory cytokines, suggesting that P. indusiatus may serve as a promising natural adjunctive candidate for managing immune imbalance in cats with FIP. Full article

The rapid evolution of coronaviruses (CoVs) requires researchers to develop specific yet broad-spectrum detection methods to monitor their constant genomic changes. The goal of the present study was to establish a current pan-coronavirus RT-PCR system capable of detecting a wide variety of CoVs and useful for the investigation of virus diversity and host spectrum. For optimization, one-step and two-step nested RT-PCRs with three RT enzymes were examined, amplifying a ~600 bp long product of the RNA-dependent RNA polymerase. As templates, the in vitro transcribed RNA of ten pathogenic CoVs (SARS-CoV, SARS-CoV-2, NL-63, OC43, feline CoV, porcine epidemic diarrhea virus or PEDV, transmissible gastroenteritis virus or TGEV, canine CoV, bat CoV, and infectious bronchitis virus) were applied instead of the often-used DNA standards. A limit of detection of 5–50 copies/reaction was achieved with a random hexamer-primed two-step RT-PCR and a touchdown cycling profile, representing a lower detection limit and higher specificity compared to previously published primer sets. Swine origin pooled samples (n = 121), collected from apparently healthy herds in Hungary, were tested with the novel RT-PCR system. Sequences of porcine respiratory CoV/TGEV and porcine hemagglutinating encephalomyelitis virus were identified in 24 oral fluid and nasal swab pools, demonstrating the circulation of these viruses in this country, as well as the suitability of the new PCR for their detection. The results highlighted the importance of adequate RT enzyme selection and the use of RNase inhibitors in sample preparation and conservation. Full article

Feline infectious peritonitis (FIP) is a major disease of cats which, unless promptly diagnosed and treated, is invariably fatal. Although it has long been recognised that the condition is the result of an aberrant immune response to infection with feline coronavirus, there remain significant gaps in our understanding of its pathogenesis. Consequently, diagnosis is complex and relies on the combined interpretation of numerous clinical signs and laboratory biomarkers, many of which are non-specific. In the case of effusive FIP, a commonly encountered acute form of the disease where body cavity effusions develop; the interpretation of fluid analysis results is key to diagnosing the condition. We hypothesised that machine learning could be applied to fluid analysis test data in order to help diagnose effusive FIP. Thus, historical test records from a veterinary laboratory dataset of 718 suspected cases of effusive disease were identified, representing 336 cases of FIP and 382 cases that were determined not to be FIP. This dataset was used to train an ensemble model to predict disease status based on clinical observations and laboratory features. Our model predicts the correct disease state with an accuracy of 96.51%, an area under the receiver operator curve of 96.48%, a sensitivity of 98.85% and a specificity of 94.12%. This study demonstrates that machine learning can be successfully applied to the interpretation of fluid analysis results to accurately detect cases of effusive FIP. Thus, this method has the potential to be utilised in a veterinary diagnostic laboratory setting to standardise and improve service provision. Full article

The development of eco-friendly antimicrobial materials is essential for addressing antibiotic resistance, while reducing environmental impact. In this study, bio-derived anionic and cationic cellulose nanofibers (a-CNF and c-CNF) were employed as templating matrices for the in situ hydrothermal synthesis of cellulose/ZnO nanohybrids. Physicochemical characterization confirmed efficient cellulose functionalization and high-quality nanofibrillation, as well as the formation of uniformly dispersed ZnO nanoparticles (≈10–20 nm) strongly integrated within the cellulose network. The ZnO content was 30 and 20 wt. % for a-CNF/ZnO and c-CNF/ZnO, respectively. Antibacterial evaluation against Escherichia coli and Staphylococcus aureus revealed enhanced activity for both hybrids, with c-CNF/ZnO displaying the lowest MIC/MBC values (50/100 μg/mL). Antiviral assays revealed complete feline calicivirus inactivation at 100 μg/mL for c-CNF/ZnO, while moderate activity was observed against bovine coronavirus, highlighting the role of surface charge. Cytotoxicity assays on mammalian cells demonstrated high biocompatibility at antimicrobial concentrations. Life cycle assessment showed that c-CNF/ZnO exhibits a lower overall environmental burden than a-CNF/ZnO, with electricity demand being the main contributor, indicating clear opportunities for further reductions through process optimization and scale-up. Overall, these results demonstrate that CNF/ZnO nanohybrids effectively combine renewable biopolymers with ZnO antimicrobial functionality, offering a sustainable and safe platform for biomedical and environmental applications. Full article

The ongoing emergence of antiviral drug resistance underscores the critical need for new broad-spectrum antiviral agents. Sulfonamides and their derivatives have emerged as promising candidates for the development of new antiviral therapeutics. In this study, a series of camphor-10-sulfonamide derivatives was synthesized through a feasible and sustainable synthetic approach starting from naturally available precursors and evaluated for antiviral properties. Their activity was examined against three structurally distinct viruses—herpes simplex virus type 1 (HSV-1), human coronavirus (HCoV-OC43), and feline calicivirus (FCV)—representing both DNA and RNA, enveloped and non-enveloped types. The compounds were examined for their effects on viral replication, the stage of viral adsorption to the cell, and extracellular virions. The weakest cytotoxicity and the most pronounced activity of all the tested substances was demonstrated by the tryptophan derivative 7a. A time-dependent inhibition of the stage of adsorption of HCoV-OC43 (Δlg = 2.0 at 120 min) and FCV (Δlg = 1.75 at 60 min) to susceptible cells was established, as well as virucidal activity on the three types of virions tested, with the most pronounced effect at 120 min—for HSV-1 (Δlg = 2.75) and Δlg = 2.0 for HCoV-OC43 and FCV. Molecular docking studies performed using Glide (Schrödinger) provided insights into the active conformations of the most effective ligands and predicted possible interactions with relevant viral targets, supporting their potential as lead structures for further therapeutic development. Full article