Panleukopenia Research Articles

Prognostic value of neutrophil to lymphocyte ratio and platelet indices in cats with feline panleukopenia

The aim of this study was to ascertain the prognostic significance of the neutrophil to lymphocyte ratio (NLR) and platelet indices during hospital admission in cats with feline panleukopenia (FPV). A prospective observational study was conducted on 24 cats diagnosed with FPV. The results of the study demonstrated a significant decrease in NLR, platelet count (PLT), and platelet concentration (PCT) in the FPV survivor group compared to the control group. Furthermore, these parameters exhibited a notable decline in the FPV non-survivor group when compared to both the control group and the FPV survivor group. In contrast, mean platelet volume (MPV) and platelet distribution width (PDW) were significantly elevated in the FPV non-surviving cats compared to the control group. Moreover, receiver operating characteristic (ROC) curve analysis was employed to identify a prognostic cut-off value for predicting the prognosis of cats with FPV. The positive predictive values (PPVs) for survival were determined to be 90 %, 95 %, 85 %, 85 %, 85 %, and 75 %, respectively, using cut-off values of NLR (≤ 0.29), PLT (≤ 202.5 ×10³/µL), PCT (≤ 0.19 %), MPV (≥ 10.3 fL), and PDW (≥ 34.9 %). Based on the sensitivity, specificity and positive predictive values obtained from the ROC analysis, it was concluded that the NLR, MPV, and PLT are excellent biomarkers for determining prognosis in cats with FPV. Nevertheless, the PLT level is of greater significance, exhibiting a higher AUC.

Two novel sites determine genetic relationships between CPV-2 and FPV: an epidemiological survey of canine and feline parvoviruses in Changchun, China (2020)

Canine parvovirus (CPV-2) and feline parvovirus (FPV) cause severe hemorrhagic diarrhea disease in dogs, cats, and fur-bearing and wildlife carnivores worldwide, continuing to pose significant threats. In this study, 140 rectal swabs were collected from 70 domestic dogs and 70 cats with clinical diarrhea in veterinary clinics in Changchun during 2020. A total of 64.3% (45/70) of dogs and 55.7% (39/70) of cats tested positive for CPV-2 or FPV using colloidal gold strips. Amino acid (aa) sequence alignment of the VP2 protein from 39 CPV-2 and 36 FPV samples revealed that 79.5% (31/39) were CPV-2c, 17.9% (7/39) were a new CPV-2a, and 2.6% (1/39) were mink enteritis virus (MEV). and 8.3% (3/36) FPV from the cats was infected by CPV-2, which suggested that CPV-2c was the dominant variant in dogs and FPV was the major pathogen in cats in Changchun city. Phylogenetic relationships of VP2 genes showed that 26 parvoviruses were closely related to domestic strains previously published in China; however, 8 FPVs and CPV-JL-15/China/2020 were clustered in the lineage of South Asiatic and European countries, and 7 out of 8 FPVs were close to Italy. In addition to Q247H, I248Y, F544Y, and E/V545V/K, two novel site mutations of N23D or L630P in NS1 protein, associated with viral cross-species transmissions, were first found as a reminder of genetic relationships of CPV-2 variants and FPVs in the same branch. Thus, regular and massive virus surveillance of parvovirus is necessary to cope with its ongoing infection, circulation, mutations, and evolutions to new subtypes with strong survival abilities.

First Isolation and Characterization of Feline Panleukopenia Virus From Wild Raccoon Dogs in the Residential Area of Shanghai, China.

Carnivore parvovirus is commonly detected in canines and felines and results in a range of symptoms, including diarrhoea, with a high lethality rate. In recent years, the gradual restoration of urban ecosystems coupled with a lack of natural predators means that wild raccoon dogs have gradually entered residential neighbourhoods in Shanghai, and the carnivore parvovirus carried by such canines may seriously affect their health and that of dogs and cats in these neighbourhoods. Therefore, it is essential to monitor wild raccoon dogs for carnivore parvovirus. The wild raccoon samples were collected from the residential area of Shanghai and screened for parvovirus, followed by virus isolation and sequence comparison analysis. In this study, three strains of parvovirus, YSH1-2022, YSH2-2022 and GSW1-2023, were isolated from anal and pharyngeal swab mixtures of 42 live raccoon dogs and two dead raccoon dogs in Shanghai, China. After alignment, it was found that the three strains of parvovirus were all located in the same branch as feline panleukopenia virus (FPV), and the three VP2 genes had 100% homology with FPV VP2 genes isolated from Shanghai and Yangzhou, Jiangsu Province. The homology of the three NS1 genes with FPV NS1 isolated from Shanghai and other places was 99.9%-100%. This is the first report of FPV isolated from raccoon dogs. In this study, the host range and risk of infection of parvovirus were evaluated, providing data to support wildlife management and policy formulation in Shanghai.

Evolutionary Dynamics and Pathogenicity Analysis of Feline Panleukopenia Virus in Xinjiang, China

Feline panleukopenia virus (FPV), a globally pervasive and highly pathogenic pathogen, has garnered significant attention recently due to the cross-species transmission of its variants. Despite the vast body of research conducted on FPV, studies exploring its evolutionary history, dynamics, and the factors driving its evolution remain scarce. The pathogenicity of strains with the prevalent mutations (A91S and I101T) in the VP2 protein has also not been fully elucidated. This study conducted a comparative analysis of FPV VP2 sequences sourced from Xinjiang province in China, other provinces in China, and other countries. It was confirmed that the evolutionary rate of FPV approached that of RNA viruses, at approximately 1.13 × 10−4 substitutions/site/year. The study reconstructed molecular models of the VP2 protein with the A91S and I101T mutations and used viral strains carrying these mutations to perform the animal regression experiment. It was confirmed that isolates with the A91S and I101T mutations could cause typical leukopenia and acute enteritis symptoms, suggesting that the mutant strains still possess certain pathogenicity. This is the first study to report on the evolutionary dynamics of FPV in Xinjiang, China, and it emphasized the importance of continuously monitoring FPV evolutionary dynamics.

Molecular typing of Protoparvovirus carnivoran 1 in Egyptian cats diagnosed with feline panleukopenia

Feline panleukopenia (FPL) in cats is caused by either feline parvovirus (FPV) or canine parvovirus (CPV-2), which belong to the same species “Protoparvovirus carnivoran 1”. While FPV is widely recognized as the principal cause of FPL, CPV-2 has been detected at a higher rate than FPV in sick cats in a recent Egyptian study. To assess this conflict, the present study aimed to determine which Protoparvovirus carnivoran 1 is commonly associated with FPL in Egyptian cats. From Dec-2022 to Jan-2024, 43 cats presenting with acute gastroenteritis and testing positive for FPL using in-clinic assay, SNAP® parvo, were tested for Protoparvovirus carnivoran 1 DNA using conventional PCR. Typing of Protoparvovirus carnivoran 1 was conducted by partial VP2 gene sequencing. Additional epidemiological aspects of the disease were investigated, including seasonal pattern, case-fatality rate, median survival time to death, and the association between FPL outcomes and selected factors like age, sex, vaccination status, and clinical signs (vomiting and diarrhea). All cats tested positive for Protoparvovirus carnivoran 1 DNA and FPV was detected in all cats with strong PCR amplicons (n=39). The following seasonal pattern was recorded: cases emerging in autumn, peaking during winter, declining in spring, and disappearing in summer. The case-fatality rate was 41.6%, and the median time to death was two days. None of the studied factors affected FPL outcomes. In conclusion, FPL in Egyptian cat populations is primarily caused by FPV, not CPV-2, and is particularly prevalent in winter.

Correction: Isolation of a feline-derived feline panleukopenia virus with an A300P substitution in the VP2 protein and confirmation of its pathogenicity in dogs

Correction: Isolation of a feline-derived feline panleukopenia virus with an A300P substitution in the VP2 protein and confirmation of its pathogenicity in dogs

Preparation and preliminary application of fluorescent microsphere test strips for feline parvovirus antibodies

This study introduces a novel diagnostic modality for the detection of feline panleukopenia virus (FPV) antibodies in feline serum by using fluorescent microsphere immunochromatographic test strips (FM-ICTS). Leveraging the inherent specificity of antigen-antibody interactions, the FM-ICTS approach demonstrates considerable potential for efficient and accurate FPV antibody detection within a short timeframe. The FM-ICTS method demonstrates strong diagnostic performance, with consistent accuracy and stability over time. PBS buffer dilution enables detection across the range of FPV antibody haemagglutination inhibition (HI) titres in both healthy and immunized or infected cats. A high correlation (R² = 0.9733) between the T/C ratio and FPV antibody titres confirms the method’s effectiveness in quantifying these titres. Clinical validation with 84 samples supports its reliability by matching results with HI assays. Additionally, stability tests show that the test strips maintain performance during storage, with a coefficient of variation (CV) below 12% over three months at 25℃. This innovative FM-ICTS framework emerges as a promising avenue for expedient and dependable disease diagnosis within the realm of veterinary science, offering implications for timely disease management and surveillance.

Development of a recombinant Lactobacillus plantarum oral vaccine expressing VP2 protein for preventing feline panleukopenia virus

Feline panleukopenia virus (FPV) represents a significant health threat to the kittens. While traditional vaccines administered via subcutaneous or intramuscular injection are effective, they can induce stress and adverse reactions. Moreover, unvaccinated kittens visiting veterinary clinics risk exposure to FPV, increasing their susceptibility to infection. Therefore, there is an urgent need for a safer, more gentle vaccination method with streamlined administration. In this study, we developed a recombinant L. plantarum NC8/VP2 expressing the VP2 protein of the prevalent Chinese FPV strain, FPV-251. Our results show that L. plantarum NC8/VP2 effectively colonizes the feline intestinal tract and induces high levels of neutralizing antibodies through oral administration. Kittens exhibited significant protection against FPV-251 infection and associated illnesses or fatalities after 30 days of continuous dosing. These results highlight the potential of recombinant L. plantarum NC8/VP2 as a novel oral vaccine for FPV, presenting a promising approach for disease prevention in domestic cats.

Whole-genome sequence analysis of canine parvovirus reveals replacement with a novel CPV-2c strain throughout India.

Canine parvovirus (CPV) infection causes severe gastroenteritis in canines, with high mortality in puppies. This virus evolved from feline panleukopenia virus by altering its transferrin receptor (TfR), followed by the emergence of CPV-2 variants in subsequent years with altered immunodominant amino acid residues in the VP2 protein. While previous studies have focused on the VP2 gene, there have been fewer studies on non-structural protein (NS1 and NS2) genes. In the present study, CPV genome sequences from clinical samples collected from canines throughout India in 2023, previous Indian CPV isolates from 2009-2019, and the current Indian CPV vaccine strain were compared. The study showed that the CPV-2c (N426E) variant had almost completely replaced the previously dominant CPV-2a variant (N426) in India. The Q370R mutation of VP2 was the most common change in the recent CPV-2c strain (CPV-2c 370Arg variant). Phylogenetic analysis showed the existence of three clades among the recent CPV-2c strains, and sequence analysis identified several new sites of positive selection in the VP1 (N-terminus), VP2, NS1, and NS2 protein-encoding genes in recent CPV strains, indicating the emergence of new CPV-2c variants with varied antigenic and replication properties. The predominant 'CPV-2c 370Arg variants' were grouped with the Chinese and Nigerian CPV-2c strains but were separate from the CPV vaccine strain and earlier isolates from our repository. VP2 epitope analysis predicted nine amino acid variations (including two new variations) in four potential linear B-cell epitopes in the CPV-2c 370Arg variants that might make vaccine failure more likely. This pan-Indian study lays the foundation for further research concerning the dynamics of virus evolution and understanding genetic mutations.

Evaluation of feline mesenchymal stem cell susceptibility to feline viruses

Feline mesenchymal stem cells (fMSCs) are well known for their robust differentiation capabilities and are commonly used in studying immune-related diseases in cats. Despite their importance, the susceptibility of fMSCs to viral infections remains uncertain. This study aimed to assess the susceptibility of feline adipose-derived mesenchymal stem cells (fAD-MSCs) and feline umbilical cord-derived mesenchymal stem cells (fUC-MSCs) to common feline viruses, including feline coronavirus (FCoV), feline herpesvirus type 1 (FHV-1), and feline panleukopenia virus (FPV). The results demonstrated that both FCoV and FHV-1 were able to infect both types of cells, while FPV did not exhibit cytopathic effects on fUC-MSCs. Furthermore, all three viruses were successfully isolated from fAD-MSCs. These findings suggest that certain feline viruses can replicate in fMSCs, indicating potential limitations in using fMSCs for treating viral diseases caused by these specific viruses. This study has important clinical implications for veterinarians, particularly in the management of viral diseases.

Antibody response after feline panleukopenia virus vaccination in kittens with and without intestinal parasites.

Vaccinations should only be given to healthy cats, and deworming before vaccination is generally recommended; however, so far, no study has investigated the influence of intestinal parasitic infection on the immune response in kittens. The aim of this prospective study was to compare the antibody response to feline panleukopenia virus (FPV) vaccination in kittens with and without intestinal parasites. Overall, 74 healthy kittens were included. Of these, 17 had intestinal parasites (12/17 Toxocara cati, 6/17 Cystoisospora felis, 1/17 Capillaria species). Both kittens with and without (n = 57) parasites received two primary kitten vaccinations with modified live FPV vaccines in a 4-week interval starting at the age of 8-12 weeks. Anti-FPV antibodies were determined at the beginning of the study (week 0) and at week 8 (4 weeks after the second vaccination) by haemagglutination inhibition. A ⩾four-fold titre increase (week 8 vs week 0) was defined as a response to vaccination. Comparison of the immune response in the kittens with and without intestinal parasites was performed using Pearson's χ2 test. Pre-vaccination antibodies were present in 4/17 (23.5%) kittens with intestinal parasites and in 24/57 (42.1%) without parasites. A ⩾four-fold titre increase was seen in 13/17 (76.5%) kittens with parasites compared with 32/57 (56.1%) kittens without parasites. There was neither a significant difference in pre-vaccination antibodies (P = 0.17), nor in vaccination response (P = 0.13) between kittens with and without parasites. The results indicate that asymptomatic intestinal infections with endoparasites do not interfere with the immune response to kitten vaccination series. Parasitic infection (at least with T cati, C felis and Capillaria species) is therefore not a reason to postpone important vaccinations.

Illegal Wildlife Trade gives insights into suspected Feline Panleukopenia Virus (FPV) Occurrence in Puma concolor

Illegal Wildlife Trade gives insights into suspected Feline Panleukopenia Virus (FPV) Occurrence in Puma concolor

Identificación de genogrupos de protoparvovirus y sus variantes en leucocitos de gatos domésticos del Valle Central de Costa Rica

Carnivore protoparvovirus 1 (CPPV-1) includes feline parvovirus (or feline panleukopenia virus, FPV) and canine parvovirus 2 (CPV-2). Currently, although CPV-2 is not found in nature, its variants CPV-2a, CPV-2b, and CPV-2c are found and can infect cats as well. The objective of this research was to identify CPPV-1 and its variants as antibodies against CPPV-1 in the blood of domestic cats from the Central Valley of Costa Rica. Blood samples were collected from 155 cats, along with the following data: sex, age, breed, vaccination information, the environment where the animal lives (urban or rural), coexistence with other cats, health status, any chronic diseases, lifestyle (indoor or outdoor cat), and place of origin. Blood samples were analyzed by hemagglutination inhibition assay (HIA) and molecular techniques (polymerase chain reaction (PCR) and sequencing). Antibodies against CPPV-1 were detected using HIA in all cats; a total of 112 (72.3%) had protective titers (≥1:80). Using real-time PCR, CPPV-1 was detected in the blood of 42 (27.1%) cats, none of which presented anemia, leukopenia, or any chronic disease; five (11.9%) were vaccinated, and three (7.1%) had low body condition but showed appetite and had no other symptom or sign associated with CPPV-1. The group of qPCR-positive cats did not show significant differences compared to the qPCR-negative group regarding age, sex, lifestyle, coexistence with other cats, and antibody titers. Ten asymptomatic and healthy cats showed FPV (n=2) and CPV-2c (n=8) in blood with nucleotide similarities of 100% (GenBank M38246) and 99.8%-100% (GenBank AF401519), respectively.

Isolation and genetic characterization of parvoviruses from domestic cats reveals emergence of CPV-2c in India: A first report.

The objective of the present study was to isolate and characterize the VP2 gene of parvoviruses from domestic cats in India. For that, 38 fecal samples were screened by PCR with 36.84% positivity. Sequence analysis of those isolates showed canine parvovirus type-2c (CPV-2c) as the predominant variant, followed by feline panleukopenia virus (FPV) and 2a. Phylogenetic analysis of the CPV-2c sequences revealed clustering with Singaporean, South Korean, Mongolian and Bangladeshi dog 2c sequences. Phylogenetic analysis of the 2a isolate (MZC 2) was found to be clustered with Indian, Thai and Singaporean dog 2a isolates. Similarly, all the four FPV sequences were ancestrally related to Indian dog and cat FPV sequences hinting towards interspecies transmission between dogs and cats. Both synonymous and non-synonymous mutations were evident in CPV-2c, 2a and FPV sequences indicative of active evolution. In cell culture medium, CPV-2 showed cytopathogenic effects at the third passage level. In conclusion, the study provided the first report of CPV-2c in cats from India, which demands for extensive epidemiological surveillance to monitor interspecies spread and to shed more light on viral phylogenomics, their distribution in the country and in the Southeast Asian region and usage of current vaccines.

Causes of shelter cats mortality in the Czech Republic

Awareness of the causes of mortality in shelter cats can contribute to its effective reduction. The aim of this study was to investigate the causes of mortality in cat shelters in the Czech Republic, taking into account the age of the animals and their length of stay in the shelter facilities until natural death or euthanasia. A cooperation with two private no-kill shelters in the Czech Republic was established. The subject of the study were records of 3047 cats admitted to the selected shelters in the period from 2013 to 2023. A total of 357 (11.7 %) out of 3047 cats died or had to be euthanized in two monitored shelters. No significant difference (p > 0.05) in the cat mortality was found between the two shelters (11.5 % and 12 %). The median length of stay of cats in the shelter until death or euthanasia was 23 days. The highest mortality was recorded in the youngest cats (≤ 6 months). The most common causes of death or euthanasia of cats in both shelters were feline infectious peritonitis (21.6 %), panleukopenia (18.5 %) and upper and lower respiratory tract infections (17.5 %). Adult and older cats were significantly (p < 0.05) more prone to death due to renal failure and cancer than young animals and kittens. The results of the study contribute to the knowledge on the health of cat population in shelters in the Czech Republic and can serve as a basis for further work that will target mortality reduction strategies in at-risk categories.

The coding complete genomic sequence of a feline panleukopenia virus detected from a domestic cat (Felis catus) in Chattogram, Bangladesh.

The coding complete genome sequence of the feline panleukopenia virus (FPLV), detected from an indigenous cat in Bangladesh, has been determined. The genome spans 4,842 bp and contains four protein-coding genes. The genome will contribute to a comprehensive understanding of the genetic traits and evolutionary trends of FPLV.

Molecular Detection of Viral and Bacterial Pathogens in Red Foxes (Vulpes vulpes) from Italy.

Animals, including wildlife, are part of One-Health concept since many infectious diseases can affect both humans and animals. In this study, 126 red foxes (Vulpes vulpes) from Northern Italy in 2022-2023 were tested by molecular assays for Protoparvovirus carnivoran 1 (PPVC-1), Canine adenovirus type 1 and 2 (CAdV-1 and CAdV-2), Circovirus canine (CanineCV), Canine distemper virus (CDV), and Leptospira spp. A total of 39 of 126 (30.9%) red foxes were infected with at least one pathogen and five of these were coinfected: 20/126 (15.9%) red foxes tested positive for PPVC-1, 3/126 (2.4%) for CAdV, 20/126 (15.9%) for CanineCV, and 2/126 (1.6%) for Leptospira spp. DNA. No foxes tested positive for CDV RNA. The pathogens identified were genetically analysed. New findings were reported such as a fox with multiple feline panleukopenia virus (FPV) and canine parvovirus type 2b (CPV-2b) infection associated with quasispecies dynamics, typical genetic characteristics of the identified CanineCV, and the first detection in red foxes of Leptospira ST198 related to L. interrogans serogroup Australis. Further studies are necessary to investigate the transmission between domestic animals and wildlife and to understand the role of red foxes in the maintenance of these pathogens not only in the wild but also in urban and peri-urban environments.

Molecular Characterization of Feline Parvovirus from Domestic Cats in Henan Province, China from 2020 to 2022.

Carnivore protoparvovirus-1, feline parvovirus (FPV), and canine parvovirus (CPV) continue to spread in companion animals all over the world. As a result, FPV and CPV underwent host-to-host transfer in carnivorous wild-animal hosts. Here, a total of 82 fecal samples of suspected cat FPV infections were collected from Henan Province from 2020 to 2022. The previously published full-length sequence primers of VP2 and NS1 genes were used to amplify the targeted genes of these samples, and the complete gene sequences of 11 VP2 and 21 NS1 samples were obtained and analyzed. Analysis showed that the amino acid homology of the VP2 and NS1 genes of these isolates was 96.1-100% and 97.6-100%, respectively. The phylogenetic results showed that the VP2 and NS1 genes of the local isolates were mainly concentrated in the G1 subgroup, while the vaccine strains were distributed in the G3 subgroup. Finally, F81 cells were inoculated with the local endemic isolate Luoyang-01 (FPV-LY strain for short) for virus amplification, purification, and titer determination, and the pathogenesis of FPV-LY was detected. After five generations of blind transmission in F81 cells, cells infected with FPV-LY displayed characteristic morphological changes, including a round, threadlike, and wrinkled appearance, indicative of viral infection. The virus titer associated with this cytopathic effect (CPE) was measured at 1.5 × 106 TCID50/mL. Subsequent animal regression tests confirmed that the virus titer of the PFV-LY isolate remained at 1.5 × 106 TCID50/mL, indicating its highly pathogenic nature. Cats exposed to the virus exhibited typical clinical symptoms and pathological changes, ultimately succumbing to the infection. These results suggest that the gene mutation rate of FPV is increasing, resulting in a complex pattern of gene evolution in terms of host preference, geographical selection, and novel genetic variants. The data also indicate that continuous molecular epidemiological surveillance is required to understand the genetic diversity of FPV isolates.

Clinical efficacy studies of the vaccine against feline panleukopenia, calicivirus infection and viral rhinotracheitis Carnifel PCH in kittens

Clinical efficacy studies of the vaccine against feline panleukopenia, calicivirus infection and viral rhinotracheitis Carnifel PCH in kittens

Rapid lateral flow immunoassay for fluorescence detection of canine distemper virus (CDV).

Canine distemper virus (CDV) is a highly contagious and potentially lethal virus that affects dogs and other members of the Canidae family, including wolves, foxes, and coyotes. Here, we present a fluorescent lateral flow immunoassay (FLFA) platform for the detection of CDV, which utilizes fluorescent microspheres - fusion protein monoclonal antibody (mAb)-labeled monoclonal antibody. The assay detected CDV within 5 min, with a detection limit threshold of 3 × 102 TCID50/mL. Notably, the assay demonstrated no cross-reactivity with canine parvovirus, canine coronavirus, canine adenovirus, feline calicivirus, feline herpesvirus, or feline parvovirus. Field and clinical applicability of the assay was evaluated using 63 field samples, including 30 canine fecal samples, 18 swab samples, and 15 blood samples. The coincidence rate between the detection results of clinical samples obtained through FLFA and reverse transcription polymerase chain reaction (RT-PCR) was 96.83%. Thus, this assay offers a significant advancement for the rapid diagnosis of CDV at the point of care.