Search Results (53)

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 panleukopenia virus (FPLV) is the primary causative agent of a highly contagious and often fatal disease affecting domestic cats and other felids. The increasing isolation of species-specific FPLV variants from multiple host species has garnered considerable attention, highlighting the need to investigate their genetic diversity. In this study, three FPLV isolates were obtained and phylogenetically classified into two distinct FPLV-China groups within separate clusters. Compared to the prototype FPLV (M38246.1), these isolates exhibited seven amino acid substitutions in the NS1 (n = 6) and VP2 (n = 1) proteins. Further analysis of 157 NS1 sequences and 947 VP2 sequences retrieved from the NCBI database revealed 113 and 479 synonymous substitutions and 71 and 279 non-synonymous substitutions, respectively. Notably, the majority of these substitutions occurred as single events (57% in NS1, 40/71; 55% in VP2, 153/279) or were present in no more than five FPLV sequences (23% in NS1, 16/71; 32% in VP2, 89/279). However, three non-synonymous substitutions in the NS1 protein (Ile443Val, His595Gln, and Val596Leu) were detected in more than half of the 157 sequences analyzed. In the VP2 protein, six non-synonymous substitutions (Ala91Ser, Thr101Ile, Val232Ile, Lys93Asn, Asp323Asn, and Val562Leu) were each found in 20 to 40 FPLV sequences. Furthermore, ten sites in the NS protein and 224 sites in the VP2 protein exhibited both synonymous and non-synonymous substitutions simultaneously. Additionally, 75 sites in VP2 harbored multiple non-synonymous substitutions. These findings provide valuable insights for future research on the genetic determinants and vaccine development of FPLV. Full article

Feline panleukopenia (FPL) is a serious viral disease caused by Feline panleukopenia virus (FPV) that causes leukopenia, lymphopenia, and neutropenia, particularly in young or unvaccinated cats. There is no specific antiviral treatment available for FPL, and treatment protocols generally consist of fluid therapy and supportive care. This study evaluated the clinical and hematological efficacy of filgrastim, a granulocyte colony-stimulating factor (G-CSF) that has shown successful results in treating FPL in various studies, and the paraimmune activator-inactivated Parapoxvirus ovis (iPPVO) in 49 cats naturally infected with FPV. Cats were randomly assigned to four groups: low-dose filgrastim (5 µg/kg, n = 13), high-dose filgrastim (20 µg/kg, n = 14), iPPVO (n = 12), and standard supportive treatment (n = 10). Clinical signs and complete blood counts were assessed on days 0 and 7. By day 7, high-dose filgrastim showed greater increases in white blood cell, lymphocyte, monocyte, and neutrophil counts compared with the other groups (p < 0.05), whereas moderate improvements were observed in the iPPVO group. Leukopenia and lymphopenia resolved faster in the high-dose filgrastim group than in the low-dose filgrastim and standard treatment groups. Clinical recovery, including reduction in vomiting and lethargy, was more pronounced in the high-dose filgrastim and iPPVO groups. Survival rates did not differ significantly among groups (p = 0.615), although the high-dose filgrastim group showed the lowest mortality (42.9%). These findings suggest that high-dose filgrastim may contribute to cytopenias and promote hematological recovery in FPL, while iPPVO may serve as a supportive immunomodulatory therapy. However, it should be noted that the efficacy of filgrastim and/or iPPVO treatments has not been definitively confirmed, likely due to the small sample size and the lack of well-controlled randomized studies. Full article

Feline panleukopenia virus (FPV) is a major feline pathogen, but canine-derived FPV variants have recently been identified. Here, we compared the pathogenicity of a canine-derived FPV strain in cats with that of a lethal feline-derived FPV strain and evaluated the evolutionary significance of its NS1 mutations. Kittens infected with the canine-derived strain developed only mild, self-limiting diarrhea without fever or mortality, whereas those infected with the feline-derived strain developed severe disease and reached humane endpoints by 9 dpi. The canine-derived strain caused prolonged fecal shedding from 6 to 38 dpi but only low tissue viral loads (10¹–10³ copies/g), while the feline-derived strain reached markedly higher loads (10³–10⁶ copies/g), particularly in the ileum, jejunum, and lungs. Viral DNA levels in the lungs, ileum, caecum, and rectum were significantly higher in the feline-derived group. Sequence analysis identified four NS1 mutations, 115I, 132L, 247Q, and 595Q, which showed stepwise evolutionary accumulation and signatures of positive selection. These findings indicate that canine-derived FPV retains infectivity in cats but exhibits attenuated pathogenicity and reduced replication fitness, highlighting NS1 as a potential determinant of host adaptation. Full article

Protoparvoviruses are highly contagious pathogens that cause severe, often fatal diseases in both domestic and wild carnivores. Golden jackal (Canis aureus) populations have experienced expansion in recent years, increasingly occupying urban and peri-urban areas. Despite this, they remain largely overlooked in scientific research. This study aimed to detect and characterise Protoparvovirus carnivoran1 circulating in a golden jackal population in Croatia and to assess their role in the epidemiology of parvovirus infections in companion animals. Small intestines from 55 jackals hunted in 2024 and 2025 were tested for Protoparvovirus carnivoran1 using real-time PCR. Positive samples were found across all sampling sites, with an overall positivity rate of 40%. Based on characteristic amino acid residues within the VP2 protein, the viruses detected in jackals were classified as feline panleukopenia virus (FPV). Phylogenetic analysis of the VP2 protein demonstrated considerable genetic diversity among strains circulating in Croatia. Additionally, a distinct group was identified, shared exclusively by Croatian domestic cats and golden jackals. Amino acid analysis revealed the novel A91T mutation, found only in jackals, and the E411Q mutation, unique to Croatian FPV strains. Structural modelling of the VP2 protein indicates that the observed mutations are located on the protein surface, within the antibody-binding site. These findings highlight the potential role of wild carnivores in parvovirus epidemiology and underscore the importance of including them in future surveillance and research efforts. Full article

Background: Feline panleukopenia virus (FPV) causes acute and frequently fatal disease in cats, underscoring the urgent need for safe, rapidly effective, and scalable vaccines. While virus-like particle (VLP) vaccines are inherently safe and immunogenic, their development is constrained by low yields of recombinant protein in insect cell expression systems. Methods: An optimized baculovirus expression vector system (BEVS) incorporating the hr1-p6.9-p10 transcriptional enhancer and the Ac-ie-01 anti-apoptotic gene was employed to enhance recombinant protein production. VP2 expression levels, viral titers, and hemagglutination activity were quantified using qPCR, SDS-PAGE/Western blotting, transmission electron microscopy (TEM), and functional assays. Immunogenicity and protective efficacy were assessed in both mice and cats through serological analysis, neutralizing antibody detection, and post-challenge clinical monitoring. Results: The optimized BEVS enhanced recombinant protein transcription by 1.5-fold, viral titers by 3.7-fold, and hemagglutination activity by 15-fold. The purified protein self-assembled into uniform 25 nm virus-like particles (VLPs). Immunization elicited earlier responses compared to commercial vaccines. Vaccinated cats maintained normal body temperature, stable leukocyte counts, and minimal viral shedding following FPV challenge. Conclusions: This study validates an enhanced BEVS that effectively overcomes VP2 yield constraints and generates highly immunogenic FPV VLPs. The platform enables rapid-onset protection and offers a scalable strategy for next-generation FPV vaccine development. Full article

This study investigated the prevalence of 11 common pathogens in dogs and cats in Shenzhen, China, from January 2022 to March 2024, aiming to enhance the understanding of their epidemiological characteristics for improved disease control strategies. Diagnostic testing for the target pathogens was performed using polymerase chain reaction (PCR), colloidal gold test strips, or fluorescence immunoassay. Statistical analysis revealed that among 13,134 cats, Feline Panleukopenia Virus (FPV) showed the highest prevalence (35.83%), followed by Feline Calicivirus (FCV, 26.20%), Feline Infectious Peritonitis Virus (FIPV, 22.00%), and Feline Herpesvirus (FHV, 15.76%). Among 3626 dogs, Canine Parvovirus (CPV) and Canine Distemper Virus (CDV) were predominant, showing a prevalence of 54.55% and 42.83%, respectively. Risk factor analysis showed that most infections occurred in unvaccinated animals and young individuals (<1 year old), with higher incidences in winter and spring. Logistic regression indicated that sex, age, and season were significantly associated with FPV, FHV, and FIPV infections, while age and season were associated with FCV, CPV, and CDV infections (sex showed no association). This study contributes to the epidemiological knowledge of common infectious diseases in dogs and cats, providing a theoretical basis for disease prevention in dogs and cats. Full article

Protoparvovirus carnivoran 1 (PPVC-1), Canine adenovirus type 1 and 2 (CAdV-1 and CAdV-2), and Canine circovirus (CanineCV) are highly diffusive viruses that affect domestic and wild carnivores worldwide, yet limited data are available on their circulation in Eastern European countries. In this retrospective study, the presence of these DNA viruses was investigated using molecular assays on fecal samples from 89 companion animals (56 dogs and 33 cats) collected in Romania between 2019 and 2021. The pathogens identified were analyzed genetically. Overall, 36/56 (64.3%) dogs and 5/33 (15.2%) cats tested positive for PPVC-1, 1/56 (1.8%) dogs for CAdV-1 and CAdV-2, and 15/56 (26.8%) dogs for CanineCV. In total, 40/56 (71.4%) dogs were positive for at least one of the screened pathogens. Novel findings in dogs included the frequent detection of canine parvovirus type 2c of Asian origin (Asian-like CPV-2c) and the first genetic data on CAdV-1 and CanineCV circulating in Romania. This study provides new insights into the epidemiology of DNA viruses in dogs and cats from Romania and highlights the need for ongoing monitoring of circulating pathogens to safeguard animal health, prevent outbreaks and limit potential transboundary spread. Full article

Feline herpesvirus type-1 (FHV-1), a double-stranded DNA virus, which is a highly infectious upper respiratory tract infection of felids, particularly in kittens. Droplet digital PCR (ddPCR) provides an absolute quantification method with high sensitivity and accuracy. This study aimed to develop a highly sensitive and accurate ddPCR assay for the detection of FHV-1. We designed primers and a probe targeting the FHV-1 glycoprotein D (gD) gene and evaluated the assay’s limit of detection (LOD), sensitivity, repeatability, and specificity in comparison to quantitative real-time PCR (qPCR). The developed ddPCR assay demonstrated a strong linear dynamic range (R² ≥ 0.99) and an exceptionally low LOD of 0.18 copies/μL, which was significantly more sensitive than the method qPCR (LOD ~10 copies/μL). Additionally, the assay exhibited high specificity with no cross-reactivity against other common feline pathogens (feline calicivirus, FCV; feline panleukopenia virus, FPV; feline infectious peritonitis virus, FIPV; Bordetella bronchiseptica and Chlamydia felis) and displayed outstanding repeatability (inter-run CV < 1.35). When applied to 118 clinical samples, the ddPCR assay achieved a significantly higher positive detection rate (27.4%) compared to qPCR (14.8%). In conclusion, we have successfully established a reliable ddPCR assay for the absolute quantification of FHV-1, providing a superior tool for laboratory diagnosis and research. Full article

Members of the Anelloviridae family are increasingly being recognized for their role in veterinary and public health, with domestic cats identified as potential carriers of anelloviruses and gyroviruses. This study aimed to investigate the prevalence and genetic characteristics of these viruses in diarrheic cats from Sivas, Türkiye. A total of 91 fecal samples were analysed, initially for feline panleukopenia virus using conventional PCR, followed by screening with our Anelloviridae panel. The results revealed that 19 (20.9%) samples were positive for TTFeV1, 32 (35.2%) for CAV, 67 (73.6%) for Avian gyrovirus 2, four (4.4%) for Gyrovirus 3, and three (3.3%) for Gyrovirus 4. Statistical analyses revealed frequent co-infections among parvoviruses, anelloviruses, and gyroviruses, with a significant association between Gyrovirus chickenanemia (CAV) and Gyrovirus galga1 (AvGyV2). Notably, Gyrovirus 4 (Gyrovirus homsa3) was identified in feline stool for the first time. Phylogenetic and genomic analyses, based on partial TATA box-ORF2 sequences for anelloviruses and VP1 sequences for gyroviruses, provided further insights into viral diversity. These findings expand current knowledge of anellovirus and gyrovirus circulation in feline populations, underscoring the importance of continued surveillance for feline and public health. Full article

Stray cats (Felis vaga) are key hosts for feline and zoonotic pathogens. From June to August 2024, we conducted a cross-sectional study across six districts in Shenzhen, China, involving 126 cats sampled from three types of sites. Multiple specimens were tested via quantitative real-time PCR (qPCR) for feline coronavirus type I (FCoV-I), feline calicivirus (FCV), feline herpesvirus type I (FHV-I), feline panleukopenia virus (FPV), and rabies virus (RABV); serum was analyzed for RABV-neutralizing antibodies by the fluorescent antibody virus neutralization (FAVN) assay. The overall pathogen positivity was 89.68%. FPV was most prevalent (61.90%), followed by FCV (57.14%), FCoV-I (46.83%), and FHV-I (23.02%). No RABV nucleic acid was detected. The co-infection rate reached 62.70%, primarily dual infections (33.33%). Geographical variation was observed, with significantly higher FCoV-I in Longgang than Futian (p < 0.05). RABV seropositivity was only 6.00%. FCV and FPV co-occurred most frequently (Jaccard = 0.456). All pathogen pairs had relative risk (RR) > 1, suggesting non-random co-infections, though not significant after correction. In summary, major feline pathogens are widespread with frequent co-infections among Shenzhen stray cats, while low rabies immunity indicates potential public health risk. Targeted control measures are warranted. Full article

Virus inactivation exhibits varying disinfection kinetics due to structural or genomic differences. Standard post-disinfection assessment relies on observing cytopathic effects in inoculated cell cultures, which are limited by sensitivity, availability, cost, and turnaround time. This study explores nucleic acid aptamers as molecular sensors to differentiate between intact and post-disinfection virus particles. To discover aptamers, 12 cycles of an automated SELEX (Systematic Evolution of Ligands by Exponential Enrichment) experiment were performed using recombinant (r)-VP2 protein of canine parvovirus (CPV). Enrichment of single stranded (ss) DNA binders was evaluated by sequencing the enriched libraries. The most abundant sequences were tested for binding with coated rVP2 and CPV (intact and treated with heat and peracetic acid (PAA) disinfectant) followed by detection using PCR. Binding specificity was assessed using intact and heat-treated feline panleukopenia virus (FPV) and porcine parvovirus (PPV). Sequencing of the DNA libraries from selection cycle 6 and cycle 12 products showed individual sequence enrichment with maximum frequencies of 2.14% and 8.65%, respectively. The top three abundant sequences from each cycle confirmed rVP2 binding. In the case of CPV, only heat-treated and PAA-treated CPV showed binding to the candidate sequences. However, reduced binding to the CPV-specific antibody was observed for rVP2 and treated CPV compared to intact CPV. No apparent binding of the tested sequences was observed for FPV and PPV. Aptamers binding to denatured but not intact CPV demonstrate the potential to distinguish between the two states, providing a basis for developing a molecular assay to assess disinfection efficacy. Full article

Canine parvovirus (CPV) is a virus of veterinary health significance and a member of the Parvoviridae family. Despite its clinical significance and global distribution, surveillance is often limited to cases serious enough to result in veterinary visit and/or hospitalization, thereby limiting our understanding of its evolution and diversity. In this study, we coupled wastewater surveillance (WWS), long-range polymerase chain reaction (PCR) and long-read sequencing and demonstrate the utility of this approach for community-level monitoring of parvovirus diversity. We screened archived viral concentrates from wastewater (WW) collected monthly from July 2022 to June 2023 as part of a previous virus surveillance study from a population of ~500,000 people in Maricopa County, Arizona, USA. Using long-range PCR, the coding-complete sequences (~4.5 kb) were amplified as single contigs and sequenced on a long-read sequencer (MinION). Reads were trimmed, assembled, and contigs subjected to a bioinformatics workflow that includes phylogenetics, immuno-informatics and protein structure modelling. The ~4.5 kb amplicons were amplified from all the samples and sequenced. Twelve contigs (length: 4555 nt to 4675 nt: GC%: 35% to 36%) were assembled from 86,858 trimmed and size-selected reads (length 4400 nt–4900 nt) and all typed as parvoviruses. Overall, there were 11 CPV variants (2a, 2b and 2c) and 1 feline panleukopenia virus (FPV) variant. The FPV was 100% similar in the VP2 genomic region to the 1964 Johnson snow leopard strain present in the Felocell vaccine, suggesting recent shedding post-vaccination. For the CPVs, our analysis showed multiple amino acid substitutions in the VP2 and NS1 proteins, suggestive of host immune pressure and viral adaptation, respectively. The CPV variants clustered predominantly with North and South American variants, suggesting transboundary viral movement and multiple CPV-2c transmission chains seem evident. To the best of our knowledge, we here document the first detection of vaccine-origin FPV in WW. We show the presence of CPV-2a, 2b and 2c in the population sampled and provide evidence that suggests transmission of CPVs across the Americas. Our results also show that WWS coupled with long-range PCR and long-read sequencing is a feasible population-level complement to clinical case surveillance that also facilitates detection of vaccine-origin virus variants. The model we demonstrate here for tracking parvoviruses can also be easily extended to other DNA viruses of human and veterinary health significance. Full article

Wild carnivores can harbor pathogens affecting wildlife conservation and domestic animal health. This study surveyed major viral pathogens in free-ranging wolves, red foxes, stone martens, and Eurasian badgers in Northwestern Italy. Duodenal samples from 140 carcasses were screened by consensus PCR for members of the species Protoparvovirus carnivoran1 and for canine adenoviruses (CAdV-1/2). PCR-positive samples underwent sequence-independent amplification and Oxford Nanopore sequencing. Canine parvovirus type 2 (CPV-2) and feline panleukopenia virus (FPV) DNAs were identified in three wolves (6.4%) and one badger (4.3%), whereas CAdV-1 was detected in one red fox (1.8%). Nanopore sequencing yielded near-complete genomes of two CPV-new 2a, one CPV-2c, and one FPV strains, along with partial CAdV-1 sequences. Furthermore, the complete genome of a canine circovirus (CaCV) strain in co-infection with a CPV-2c-positive wolf and partial sequences of a canine kobuvirus (CaKoV) strain were also obtained. Phylogenetic analysis placed these viruses within known European lineages and linked them to domestic and wild hosts. These findings revealed the circulation of multiple viral pathogens among wild carnivores, reflecting ongoing cross-species spillover. Continuing molecular surveillance at the wildlife–domestic interface is recommended. Full article

Feline panleukopenia virus (FPLV) is a significant causative agent of disease in both domestic cats and wild carnivores that poses a considerable threat to their health. Despite its clinical importance, the mechanisms underlying FPLV–host interactions remain poorly understood. In this study, we conducted a systematic analysis of transcriptomic changes in feline kidney cells (F81) infected with a Chinese FPLV strain using RNA-seq. The down-regulated differentially expressed genes (DEGs) were majorly enriched in the regulation of the cell cycle, cell growth, or cell senescence, while the up-regulated DEGs were found to be significantly associated with cellular pathways involved in cell cycle regulation, extrinsic apoptotic signaling, and key host immune responses, including Toll-like receptor, JAK-STAT, IL-17, and TNF signaling pathways. By validating the RNA-seq data with RT-qPCR (real-time quantitative PCR) results, we identified potentially important immune-associated genes involved in the host immune response to feline panleukopenia virus, including IGSF6, IFI44L, IFI6, IFITM10, IL1R1, and JAK3. Overall, our results provide valuable insights into the mechanisms underlying feline panleukopenia virus and its interactions with its host, laying the foundation for future research on this significant virus and its impact on feline health. Full article