Computation-driven discovery of a next-generation canine monoclonal antibody for canine parvovirus therapy.

Preparation of poloxamer-based CPV virus-like particle vaccine and its immunological evaluation in mice.

A recombinant full-length VP2-2b-based ELISA for evaluating immunoprotection against canine parvovirus-2: Expression, development and validation.

Necropsy and histopathology of a juvenile bobcat (Lynx rufus) revealed neuronal necrosis with nuclear inclusion bodies and vacuolation and immunolabeling with parvovirus immunohistochemistry. Infection with canine parvovirus was confirmed by PCR. This brain lesion is an uncommon manifestation of parvovirus in non-neonatal animals and is particularly rare in wild felids.

Emergence of epidemic viruses in new hosts threatens both human and other animal populations, and often involves virus evolution to overcome barriers that normally prevent efficient infection and spread in that host. After transfer the separated viruses will evolve in parallel as they spread within the original and new hosts. Here we examine the details of a virus involved in such a host-jumping event, where we define the natural evolution of feline panleukopenia virus (FPV) over 60 y, clarify the origins of the new pandemic canine parvovirus (CPV) that arose in the 1970s, and compare the separate evolution of those viruses over 47 y in cats or dogs. Several live-attenuated FPV vaccine viruses originated from early-1960s isolates or were a recombinant of an early virus, and many sequences in databases proved to be vaccine-derived. The sequences of wild viruses showed that FPV-like strains evolved at less than one-third the rate observed for CPV in dogs, and the higher rate of CPV evolution has been consistent since 1979, when a genetic variant became widespread. The common ancestor of the CPV lineage was related to FPVs from Europe and contained several unique host-adaptive capsid changes associated with canine transferrin receptor type-1 binding. Although the FPV vaccine strains are around 60 y old, little selection for antigenic variation was observed. The distinct evolutionary patterns of these closely related viruses circulating for decades in different hosts emphasize the complex evolution associated with viral epidemic emergence and spread in endemic and new hosts.

To compare canine parvovirus (CPV) antibody titers in sera of community blood-donor dogs using the hemagglutination inhibition (HI) assays from 2 state veterinary diagnostic laboratories (VDLs) and a dot-blot ELISA assay to determine intermethod agreement. Stored sera (-80-°C freezer) from 100 healthy community-based blood-donor dogs were selected. Dogs represented various breeds and ages. Available vaccination history was retrospectively assessed. Sera were thawed and delivered to the VDLs, with HI and the dot-blot ELISA assay performed the following day. Of 100 samples, 96 dot-blot ELISA results were within a 2-fold dilution of the corresponding HI titer from the Colorado State University VDL, and 92 were within a 2-fold dilution of the HI titer from the New York State VDL. The dot-blot ELISA assay demonstrated high sensitivity (96% and 97%) and strong agreement (Spearman ρ = 0.72 and 0.92). Of 43 dogs with vaccination history, 93% had protective titers. The 3 lowest titers occurred in dogs vaccinated within 1 year. CPV antibody titers in community blood-donor dogs showed strong agreement between HI assays and the dot-blot ELISA assay. A high concordance and strong correlation support the dot-blot ELISA assay as a reliable method for estimating CPV antibody titers. Accurate, rapid assessment of CPV titers is important for selecting plasma from community blood-donor dogs intended for passive immunotherapy in critically ill parvoviral patients. Demonstration of strong agreement between the dot-blot ELISA and reference HI assays supports the use of this assay for in-house donor screening and timely plasma selection.

Canine parvovirus is one of the most common causes of infectious enteritis in puppies worldwide. Although various biomarkers have been evaluated to predict prognosis in dogs with parvoviral enteritis (CPE), many are not feasible in routine practice. The neutrophil myeloperoxidase index (MPXI; derived from the Advia 2120 hematology analyzer, Siemens), has shown promise as a marker of inflammation and disease severity in other species. We compared the MPXI in 47 client-owned dogs with established prognostic indicators, including total WBC, neutrophil and lymphocyte count, and serum concentrations of total thyroxine, cortisol, and C-reactive protein (CRP). The MPXI in dogs with CPE did not differ significantly from healthy controls when measured at admission (p = 0.444), at 24 h (p = 0.332), or at 48 h (p = 0.279) after admission. At 24 h after admission, MPXI had a strong positive correlation with serum cortisol (r = 0.87; p < 0.001) and CRP (r = 0.71; p = 0.003) concentrations and a strong negative correlation with WBC (r = -0.82; p < 0.001), neutrophil (r = -0.77; p < 0.001), and lymphocyte (r = -0.90; p < 0.001) counts, as well as serum thyroxine concentration (r = -0.78; p < 0.001). MPXI did not distinguish between diseased and healthy animals. However, increased MPXI in dogs with parvoviral enteritis may indicate the presence of immunoparalysis and be associated with a worse prognosis. Larger prospective studies, including mortality data, are warranted to evaluate MPXI as an accessible and cost-effective prognostic biomarker in CPE.

To evaluate the efficacy of a novel spectrum-of-care fecal microbiota transplant (FMT) dosing regimen as an adjunctive therapy for canine parvovirus (CPV). 27 client-owned dogs naturally infected with CPV were enrolled from March to November 2023 in a prospective, double-blinded, placebo-controlled clinical trial. Patients were randomized into FMT-treated (n = 19) or placebo-treated (8) groups. Along with conventional treatments, CPV-infected dogs were administered FMT (single FMT enema, then 14 days of oral lyophilized FMT capsules) or placebo (single saline enema, then 14 days of oral placebo capsules) at admission. During hospitalization, dogs were monitored daily including fecal, clinical severity, and medication scores. Feces and serum were collected at admission, day 4, day 7, day 14, and day 21 for quantification of CPV viral shedding and immune response (bead-based multiplex of cytokines/chemokines). The primary outcome variable was length of hospitalization. Interim analysis revealed that placebo-treated dogs had excessive study withdrawals due to worsening clinical status when compared to FMT-treated dogs (37.5% compared to 0%, respectively), leading to ethical discontinuation of the placebo arm. Fecal microbiota transplant-treated dogs had significantly reduced hospitalization length and medications required for treatment (maximum medication score) compared to placebo-treated dogs. Fecal microbiota transplant did not reduce fecal viral shedding or elicit a host immune response. This novel FMT dosing regimen (single enema FMT followed by oral capsular FMT), designed to be feasible for inpatients or outpatients, accelerated clinical recovery from CPV. In-house and commercially available FMT products were effective in CPV-infected dogs, thus broadening the spectrum of care available to these patients.

This critically appraised topic (CAT) explored the association between body weight and survival in dogs with canine parvovirus (CPV). A systematic literature search identified six peer-reviewed studies published between 1978 and 2024 that met predefined inclusion criteria. Four of the six studies demonstrated a significant association between lower body weight and increased mortality. While some studies undertook multivariable analysis to account for confounders, limitations including inconsistencies in study design, retrospective data collection, and limited control for variables such as age, breed, and body condition score (BCS) reduce the overall strength of the conclusions. Overall, there is moderate evidence to suggest that lower body weight may be a negative prognostic factor in CPV survival. Further prospective research with standardised methodology is essential to validate these findings and disentangle the impact of confounders such as age, breed, and BCS.

Background: Canine Parvo virus (CPV) infection is one of the devastating diseases of viral etiology affecting all age group of dogs and most commonly its occurrence is seen in pups below eight weeks age causing nearly 90 percent mortality. Methods: In our study, 348 samples were collected from pet dogs with clinical symptoms such as bloody diarrhoea, gastro enteritis and lethargy over the period of 3 years (2020 to 2022) at Gujarat Veterinary Research and Diagnostic Centre, Ahmedabad and investigated further using Canine Parvovirus Rapid Antigen Test Kit (Ubio Biotechnology Systems). Results: Total 214 (61.49%) cases were reported to be positive. CPV infection was higher (89.72%) in age group with pet dogs less than 6 months, sex wise prevalence was higher in males (79.9%) whereas season wise higher rates were evident in winter (22%).

Canine parvovirus type 2 (CPV-2) infection is reported in vaccinated puppies in Egypt, yet contributing factors remain poorly investigated. This study evaluated the role of vaccination practices and CPV-2 antigenic variation in disease occurrence in puppies whose primary vaccination series was recorded as finished by attending veterinarians. Puppies with clinical signs of parvoviral enteritis at three veterinary clinics in Giza, Egypt (June–October 2020) were enrolled if vaccination history was documented. All non-vaccinated puppies were included, whereas among vaccinated puppies, only those with a stamped finished primary vaccination series regardless of whether international guidelines had been followed were included. Rectal swabs were collected for PCR and VP2 gene sequencing. For vaccinated puppies, associations between PCR positivity and different aspects of vaccination practices, including age at finishing the vaccination series, number of doses, and vaccinal strain, were assessed. The finishing age was categorized as recommended (the final dose was given at ≥ 16 weeks of age, according to international guidelines) or early (< 16 weeks of age). CPV-2 variant distribution among vaccinated and non-vaccinated puppies was also evaluated. Fifty-eight puppies met the inclusion criteria (41 vaccinated, 17 non-vaccinated). CPV-2 was PCR-positive in 28/41 vaccinated and 13/17 non-vaccinated puppies. Early finishing of the primary vaccination series was significantly associated with CPV-2 infection (P < 0.001), whereas vaccinal strain and number of doses were not. Disease developed within one month of vaccination, including six puppies within one week. Sequencing identified 35 new CPV-2a, 3 CPV-2b, and 3 CPV-2c variants, with no significant difference in variant distribution between vaccinated and non-vaccinated puppies (P = 0.16). Finishing the primary vaccination series at ≥ 16 weeks of age, in accordance with international guidelines, is critical to overcome maternally derived antibody interference. Antigenic variation appears to play a minor role in disease occurrence in this setting. CPV-2 Infection after the perceived finishing of vaccination highlights a safety gap, where the veterinary stamp occurs before the 16-week threshold required for effective protection.

Canine parvovirus 2 (CPV-2) remains a leading cause of acute infectious gastroenteritis with high global morbidity in dogs. While murine neutralizing monoclonal antibodies (mAbs) are widely used for antiviral therapy, their efficacy is limited by immune rejection in canine recipients. Here, we developed an efficient single B-cell cloning platform to generate canine-derived neutralizing mAbs against CPV-2 and characterized their germline gene usage patterns. Specifically, using biotinylated CPV-2 virions as bait, CPV-2-binding B cells were singly isolated via fluorescence-activated cell sorting (FACS) from peripheral blood mononuclear cells of immunized dogs. The heavy and light chain variable region (VH/VL) sequences were amplified through nested RT-PCR from single B cells, and cloned into canine immunoglobulin heavy/light chain (IgH/IgL) expression vectors. A total of 22 canine-derived mAbs were successfully expressed and purified from suspended ExpiCHO-S cells, and 20 of which demonstrated CPV-2-binding reactivity in enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence assay (IFA). Among these, 13 mAbs exhibited neutralizing activity (IC50 < 25μg/mL) against a CPV-2c strain in F81 cells by virus micro-neutralization assays. Notably, the clone B11 showed potent virus neutralization activity with an IC50 of 0.06μg/mL. Furthermore, germline gene usage analysis revealed preferential utilization of IGHV3-5, IGHD1, and IGHD3 in the heavy chain, and IGLV1-46, IGLV1-48, and IGLJ4/9 in the light chain in these CPV-2-specific canine antibodies. These canine-derived mAbs show promise for clinical diagnostics and therapeutics, overcoming the limitations of murine antibodies. Our platform establishes a framework for developing canine mAbs against other pathogens. KEY POINTS: Efficient single B-cell platform developed for rapid canine mAb generation. Potent canine mAb identified with an IC50 of 0.06μg/mL against CPV-2c. Preferential germline gene usage revealed in canine antibody response to CPV-2.

Canine parvoviral gastroenteritis is one of the most common viral diseases found in dogs and caused by canine parvovirus (CPV) type 2. Young dogs are highly susceptible to the disease with high morbidity and mortality. The present study was conducted at the Department of Veterinary Medicine, Veterinary College, Bengaluru to know the occurrence pattern of CPV infection among PCR positive dogs under one year of age presenting with signs of gastroenteritis. The occurrence of CPV infection was high in puppies less than three months old, non-descript, male, irregularly dewormed, unvaccinated dogs weighing between four andeight kilograms, acquired from breeding kennels and housed indoors in a multi-pet household. These epidemiologic patterns highlighted the need for timely vaccination, deworming and biosecurity measures to mitigate CPV burden and improve survival in puppies.

Feline herpesvirus-1 is a local contact-infectious pathogen that causes acute upper respiratory tract infections in cats. This virus exclusively affects felines, with a clinical incidence rate of nearly 100%, particularly in young cats. To address this health concern, this study aimed to develop a rapid fluorescence microsphere immunochromatography assay (FM-ICA) for the direct detection of Feline herpesvirus-1 (FHV-1) antigen. This method utilizes a fusion protein and fluorescent nanoparticle-labelled monoclonal antibody to detect FHV-1 within 10min, achieving a detection limit of 2.5 × 102 TCID50/mL. Critically, the assay exhibited excellent specificity with cross-reactivity against canine distemper virus, canine parvovirus, canine adenovirus, canine coronavirus, feline plague virus, feline calicivirus, or feline infectious peritonitis virus. The field and clinical applicability of the method was evaluated using 100 clinical samples, including 30 faecal samples and 70 nasopharyngeal secretion samples from cats. The coincidence rate between the FM-ICA test results and the polymerase chain reaction (PCR) test results of the clinical samples was 99%.

Cytokine dysregulation and lymphopenia in dogs naturally infected with canine parvovirus type 2c.

In 2023, a total of 450 fecal samples were collected from healthy cats and those suspected of being infected with Feline Panleukopenia Virus (FPV) in Harbin, China. The FPV VP2 gene was detected using polymerase chain reaction (PCR). Positive samples were then subjected to VP2 sequence analysis, phylogenetic analysis, recombination analysis, and selective pressure analysis. VP2 sequence analysis showed that the nucleotide similarity of the full-length VP2 gene ranged from 98.7 to 100%, with 19 amino acid mutations observed compared to the 2008 Felocell vaccine strain (GenBank: EU49868.1). Phylogenetic analysis demonstrated that all 42 detected FPV strains clustered with recent domestic isolates. Recombination analysis identified two strains (HRB2312 and HRB2324) as recombinants between FPV and Canine Parvovirus type 2c (CPV-2c). Selective pressure analysis did not detect any positively selected sites. The findings suggest that the FPV lineages circulating in China have remained relatively stable in recent years, with evolution influenced by both random genetic drift and gene recombination. This study provides insights into the genetic diversity of FPV in Harbin, highlighting point mutations and recombination events. Further investigation is warranted to determine the antigenic compatibility of circulating recombinant strains with traditional vaccine strains.

Minute virus of canines (MVC) is an autonomous canine parvovirus that causes severe pathological outcomes, including embryo mortality, spontaneous abortion, and congenital malformations in neonatal puppies. Although MVC infection has been shown to induce host cell cycle arrest and apoptosis, the underlying regulatory mechanisms that coordinate cell proliferation and control apoptotic responses during viral replication remain poorly understood. Sirtuin 1 (SIRT1) is an NAD+-dependent deacetylase that plays a critical role in regulating cell cycle progression, DNA damage responses, and apoptosis. However, its involvement in MVC infection has not been fully elucidated. Herein, we show that MVC infection markedly upregulates the mRNA and protein expression levels of SIRT1 in a time-dependent manner. MVC infection activates the SIRT1-p53 signaling axis and modulates the acetylation status of p53. In addition, MVC alters the subcellular distribution of SIRT1, promoting its nuclear translocation and colocalization with the viral protein VP2. Functional analyses demonstrated that pharmacological activation of SIRT1 enhanced the viability of MVC-infected WRD cells (virus-tropic cell), promoting viral replication, prolonging S-phase arrest, and reducing apoptosis. Conversely, inhibition of SIRT1 produced the opposite effects, which were closely associated with regulation of the SIRT1-p53 signaling axis. Moreover, SIRT1 knockdown accelerated apoptosis and attenuated S-phase arrest, whereas SIRT1 overexpression further strengthened S-phase retention. Collectively, our findings identify the SIRT1-p53 signaling axis as an important regulator of cell cycle progression and apoptosis during MVC infection, highlighting SIRT1 as a key host factor that supports viral replication and persistence and a potential target for antiviral intervention.

Background: To date, no effective therapeutic interventions for viral infectious diseases have yet been established. A recently reported herbal medicine-based therapeutic known as “Marecipe AV” has demonstrated potent efficacy in managing viral infectious diseases. Aim: This review aimed to introduces an herbal therapy with demonstrated potent and clinically satisfactory efficacy against viral infections, and presents its therapeutic and preventive outcomes across multiple species under real-world conditions. Methods: This review summarizes the therapeutic outcomes of the Marecipe AV herbal remedy for various viral infectious diseases. Results: The findings indicate that Marecipe AV exhibits significant clinical benefits in treating a range of viral diseases, including COVID-19, African swine fever, porcine reproductive and respiratory syndrome, Newcastle disease, avian influenza, canine distemper, canine parvovirus infection, feline panleukopenia, koi herpesvirus disease, herpesviral hematopoietic necrosis disease, grass carp hemorrhagic disease, and largemouth bass ranavirus. The application of Marecipe AV herbal therapy has reduced the mortality rate associated with these lethal viral diseases from nearly 100% to close to 0%. Additionally, Marecipe AV herbal therapy has shown promising therapeutic efficacy in managing certain chronic viral infections, as well as some acute but non-fatal viral diseases, including Herpes Zoster, postherpetic neuralgia, chronic hepatitis B, feline acquired immunodeficiency syndrome, feline infectious peritonitis, feline chronic gingivostomatitis, and ulceration and erosion lesions in largemouth bass. However, the Marecipe AV herbal therapy appears to only inhibit the virus but cannot completely eliminate it. The long-term effectiveness of Marecipe AV herbal therapy in managing certain chronic viral diseases requires further investigation for validation. Conclusion: Marecipe AV herbal therapy shows potential as a groundbreaking approach to treating and managing a broad spectrum of viral infectious diseases.

The swift fox (Vulpes velox) is a small canid species occupying mixed and short-grass prairie ecosystems across western North America. Populations have declined across a large portion of their historical habitat distribution, mainly due to anthropogenic influences. Although some populations appear to be rebounding, the swift fox is classified as a species of greatest conservation need in Wyoming, USA, due to threats from predation, vehicular collisions, and habitat alterations that increase potential contact with humans and domestic animals. This potential contact with other species puts swift foxes at risk from infectious disease transmission, potentially resulting in morbidity or mortality. There are few published studies about disease seroprevalence and presence of parasites from swift foxes within Wyoming. Serum samples (n=103) and fecal samples (n=113) from live swift foxes were opportunistically collected from southeastern Wyoming (2009 and 2020-24) and submitted for testing. Serum samples were assessed for antibodies using an indirect fluorescent antibody test, canine parvovirus (CPV), and virus neutralization tests, canine distemper virus (CDV) and canine adenovirus (CAV). Fecal samples were tested using a standard fecal float and a real-time PCR for Echinococcus spp. and Echinococcus multilocularis. Not all samples could be tested for every assay. Overall, 58 (73%; n=80) foxes were seropositive for CPV, 5 (19%; n=27) for CAV, and 1 (2%; n=53) for CDV. Toxascaris leonina was the most commonly detected (31%; n=44) gastrointestinal parasite, and Echinococcus spp. was detected in one individual (0.9%; n=113). These results reveal previously unidentified levels of seroprevalence and lack of difference between age and sex in this species. Continued exploration and surveillance is needed to assist in determining associated morbidity and mortality and to identify risk factors (e.g., domestic canid, other wild canid comingling) contributing to disease transmission within this population.

A replication-defective bivalent adenovirus-vectored vaccine provides robust and durable protection against both canine distemper virus and canine parvovirus.