Epidemiological and Molecular Investigation of Feline Panleukopenia Virus Infection in China

The feline panleukopenia virus (FPV) is a highly contagious virus that affects cats worldwide, characterized by leukopenia, high temperature and diarrhea. Recently, the continuous prevalence and variation of FPV have attracted widespread concern. The aim of this study was to investigate the isolation, genetic evolution, molecular characterization and epidemiological analysis of FPV strains among cats and dogs in China from 2019 to 2024. The 41 FPV strains, including 38 feline strains and 3 canine strains, were isolated from rectal swab samples by inoculating monolayer FK81 cells and performing a plaque purification assay. The viral and hemagglutination titers of these 41 FPV strains were 104.33~106.33 TCID50/0.1 mL and 7.0 log2~9.7 log2, respectively. Based on the complete VP2 gene, the nucleotide homology of these FPV strains was 98.91~100%, and the homology with 24 reference FPV strains from different countries and hosts was 98.85~100%. The phylogenetic analysis revealed that 41 FPV strains were more closely related to the FPV strains of Asian origin (Asian FPV strain group) than those of European and American origin (European and American FPV strain group). Furthermore, 12 mutation sites of the VP2 protein were found in these FPV strains, of which 91 and 232 amino acid sites were previously reported. Moreover, the 91 amino acid site was found to be a positive selection site with the highest dN/dS value in the selection pressure analysis. Importantly, 35 FPV strains with 91S substitution in the VP2 protein (FPV-VP2-91S strains) had formed obvious evolutionary branches in the Asian FPV strain group. The analysis of all available VP2 protein sequences of Chinese FPV strains in the GenBank database showed that the occurrence rate of FPV-VP2-91S strains had been increasing from 15.63% to 100% during 2017~2024, indicating that the FPV-VP2-91S substitution in the VP2 protein was a noteworthy molecular characteristic of the dominant FPV strains in China. These results contribute to a better understanding of their genetic evolution and renew the knowledge of FPV molecular epidemiology.

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.

Viral pathogens in domestic cats in southern Italy: A retrospective analysis in Sicily, 2020-2022

A retrospective study was carried out on selected feline viral pathogens detected in domestic cat in Sicily, southern Italy. Samples from 64 cats, collected from 2020 to 2022, were analysed for the presence of feline panleukopenia virus, canine parvovirus type 2 (CPV-2), feline coronavirus (FCoV), feline calicivirus (FCV), feline herpesvirus type 1, norovirus (NoV), and rotavirus (RoV). Single (45 %) or mixed (38 %) viral infections were detected. FPV, related with other Italian FPV strains, remains the main viral cause of infection (66 %). CPV-2c Asian lineage strains (3 %) were detected for the first time in domestic cats in Europe. FCoV (29.6 %), either enteric or systemic, and systemic FCV (18.7 %) infections were detected in positive cats. Less commonly reported viruses (GIV.2/GVI.2 NoVs, RoV), potentially related to the animal/human interface, were detected at lower rates as well (5 %). The present epidemiological data suggest the need to improve disease prevention, immunization, and biosecurity strategies.

Investigation of canine parvovirus occurrence in cats with clinical signs of feline panleukopenia in Slovakia - pilot study

Introduction

Feline panleukopenia is a contagious viral disease caused by the feline panleukopenia virus (FPV). A closely related pathogen is canine parvovirus (CPV), and amino acid substitutions in this virus allow it to acquire a feline host range. In feline hosts, the disease induced by CPV manifests with similar symptoms to those caused by FPV or milder ones, leading to its underdiagnosis. The aim of this study was to determine the presence of CPV type 2 (CPV-2) in cats with clinical symptoms of panleukopenia and to assess the use of commercial CPV antigen tests for the clinical diagnosis of FPV.

Material and Methods

Samples from 59 cats from central Slovakia were included in the study. Rectal swabs were collected and clinically tested for parvovirus infection using a commercial antigen test. Antigen-positive samples were confirmed by PCR targeting the viral VP2 gene. The sequences of the PCR products were established with the Sanger method.

Results

Of 59 samples, 23 were revealed to be positive for parvovirus infection by both antigen and PCR test (38.9%). Analysis with the National Center for Biotechnology Information BLASTn application showed 99.78-100% pairwise identity with FPV. The mortality rate of parvovirus-infected cats included in this study was 8.69% (2/23).

Conclusion

Although feline disease with CPV-2 was not confirmed, the CPV antigen test was able to detect FPV infection.

Genetic characterization of the parvovirus full-length VP2 gene in domestic cats in Brazil

Feline parvovirus (FPV) and canine parvovirus (CPV) are over 98% identical in their DNA sequences, and the new variants of CPV (2a/2b/2c) have gained the ability to infect and replicate in cats. The aim of this study was to determine the genetic diversity in the VP2 gene of parvovirus strains circulating in domestic cats in Brazil during a 10-year period (2008-2017). For parvovirus screening, specific PCR was performed, and 25 (34.7%) of 72 cats tested positive. The PCR-positive samples were further subjected to full-length VP2 sequencing (1755 bp), and eight sequences (36%) were characterized as FPV, seven (28%) as CPV-2a and (32%) nine (36%) as CPV-2b. One sequence (RJ1085/11) showing typical CPV amino acid (aa) at residues 80 R, 93 N, 103 A, 232 I, and 323 N could not be characterized at this time. The sequences in this study displayed aa changes previously described for FPV (A14T, A91S, I101T, N564S, and A568G) from cats and CPV-2a/2b (S297N and Y324L) from dogs. However, the Y324L mutation has not yet been reported in any CPV-2a/2b strains from cats. Phylogenetic analysis supported the division of these sequences into two well-defined clades, clade 1 for FPV and clade 2 for CPV2a/2b. Unusually, the sequence RJ1085/11 was grouped separately. Two recombination breakpoints were detected by Bootscan and 3Seq methods implemented in the RDP4. This study is the first report of CPV-2a/2b in cats in Brazil. The detection of FPV strains with mutations characteristic of CPV indicates that Brazilian FPV strains have undergone genetic changes.

Genetic characterization of parvoviruses identified in stray cats in Nigeria

Parvoviruses are a major cause of haemorrhagic gastroenteritis, leukopenia and high mortality in cats and dogs. In this study, the presence and genetic characteristics of parvoviruses circulating among cats in Nigeria are reported. Faecal samples of stray cats from live animal markets in southwestern (Oyo and Osun States) and north-central (Kwara State) Nigeria were screened for the presence of parvoviral DNA using a qPCR. Positive samples were further characterized using a qPCR based on minor groove binder probes. Overall, 85/102 (83.3 %) stray cats tested positive for feline panleukopenia virus (FPV) DNA and one cat was co-infected with canine parvovirus-2 type a. Sequence analysis of the complete capsid region of 15 Nigerian FPV strains revealed that they were up to 99.9 % similar to the American reference strain FPV-b at the nucleotide level, and three of them presented amino acid mutations in key capsid residues. This is the first report of identification and molecular characterization of FPV strains in cats in Nigeria. The high prevalence of the virus emphasizes the need for constant surveillance of the circulation of parvoviruses in Nigeria and underscores the need to deploy an effective vaccination strategy.

Genetic diversity and relatedness of feline parvovirus in Vietnam and its potential implications for canine-feline transmission

Feline panleukopenia, caused by feline parvovirus (FPV), has been studied worldwide, but there have been very few studies conducted in Vietnam. In this study, 19 rectal swab samples were collected from northern Vietnam in 2018-2019 and screened for the presence of FPV using PCR. Through sequence analysis of the full-length VP2 gene, it was found that the FPV strains detected in Vietnam were closely related to those obtained from dogs in Vietnam, Asia, Europe, and America. Moreover, the FPV strains found in Vietnam may constitute a distinct group, related to viruses sampled in China. Interestingly, most of the nucleotide changes identified were T-C substitutions.

Epidemiological and Molecular Approaches for a Fatal Feline Panleukopenia Virus Infection of Captive Siberian Tigers (Panthera tigris altaica) in the Republic of Korea

Feline panleukopenia virus (FPV), a member of the species Protoparvovirus carnivoran1, is one of the most fatal pathogens of domestic and wild carnivores. The virus endemically infects domestic carnivores worldwide and its cross-species transmission threatens endangered wild carnivores, including Siberian tigers. In this study, a fatal FPV infection in endangered Siberian tigers was investigated to trace the origin of the virus and elucidate the reason behind FPV's infection of the vaccinated tigers. Our genetic characterization and phylogenetic analysis revealed that the virus detected in the infected tigers, designated as the KTPV-2305 strain, was closely related to FPV strains circulating in Korean cats, suggesting that it might have been transmitted from stray cats wandering around the zoo. Compared with the prototype FPV reference strains, the KTPV-2305 strain carried three distinct amino acid (aa) mutations in the VP2 protein sequence (I101T, I232V, and L562V) in this study. These three mutations are commonly found in most global FPV strains, including Korean strains, indicating that these mutations are common evolutionary characteristics of currently circulating global FPVs. The reason why the vaccinated tigers were infected with FPV was most likely the insufficient protective immunity of the affected tigress or vaccine failure triggered by the interference of maternal-derived antibodies in the affected tiger cubs. These findings suggest that improved vaccination guidelines are urgently needed to save the lives of wild carnivores from this fatal virus.

Development and Application of nanoPCR Method for Detection of Feline Panleukopenia Virus

Feline panleukopenia (FP) is a severe viral illness caused by the feline panleukopenia virus (FPV), putting sectors like companion cat breeding and endangered feline conservation at risk. The virus has a high morbidity and fatality rate and is found all over the world. We created a novel FPV assay using nanoPCR technology and assessed the method's specificity and sensitivity. The approach amplified a 345 bp nucleic acid fragment with a minimum detection limit of 7.97 × 10² copies/μL, which is about 100 times greater than traditional PCR. We collected anal swabs from 83 cats suspected of FPV infection for practical application, and the FPV-positive rate determined by the nanoPCR approach was 77.1%. In conclusion, the approach is more sensitive than conventional PCR and more convenient and cost-effective than qPCR methodology and may be utilized for the clinical detection of FPV.

Transcriptomics analysis reveals key lncRNAs and genes related to the infection of feline kidney cell line by panleukopenia virus

Feline panleukopenia virus (FPV) can cause a viral disease and is responsible for severe leukopenia, gastroenteritis, and nervous signs with significant economic losses. Biochemically long non-coding RNAs (lncRNAs) can regulate the expression of mRNA in different ways, thereby causing the functional changes in host cells in response to viral infection. However, no attention has been paid until now to investigate the link between FPV pathogenesis and lncRNA. Here, through RNA sequencing, we performed a comprehensive analysis of lncRNA and mRNA in F81 cells after FPV-BJ04 strain infection. Consistent with previous studies, our data showed that lncRNAs have distinct features from mRNA. A total of 291 lncRNAs and 873 mRNAs were differentially expressed in F81 cells after FPV-BJ04 infection. GO and KEGG enrichment analysis showed that the differentially upregulated lncRNAs target genes were mainly involved in the positive regulation of transcription by RNA polymerase II and MAPK signaling pathway. The differentially downregulated lncRNAs target genes were mainly involved in the mRNA splicing and endocytosis. In addition, the differentially expressed immune pathway related genes that are targeted by lncRNA were also screened out to construct a lncRNA-miRNA-mRNA axes as a potential novel biomarkers in regulating the immune response of feline against FPV infection. Our results contribute to understand the basic role of lncRNA in F81 cells during FPV infection and lay the foundation for following research.

Metagenomic Analysis of DNA Viruses with Targeted Sequence Capture of Canine Lobular Orbital Adenomas and Normal Conjunctiva

Our study aims are: (1) to evaluate phenotypically normal canine conjunctival and orbital tissue and tissue from canine lobular orbital adenomas (CLOAs) for the presence of viral genomic material and (2) phylogenetically classify detected DNA viruses to determine if a DNA virus is associated with CLOAs. A total of 31 formalin fixed paraffin embedded CLOA tissue samples, 4 papillomas or sarcoid, and 10 fresh clinically normal conjunctival tissues were included in this study. Genomic DNA was isolated from all samples and sequencing libraries were prepared. The libraries were molecularly indexed and pooled and viral DNA was enriched via targeted sequence capture utilizing ViroCap. The libraries were sequenced on the Illumina HiSeq platform and compared to known viral DNA reference genomes to identify viral DNA. Carnivore parvovirus was identified in 6.4% and 20% of CLOA tissue and normal conjunctival samples, respectively. This study showed that conjunctival tissue from healthy dogs and CLOAs uncommonly harbor DNA viruses, and no DNA virus was associated with these tumors. Further studies are needed to evaluate the etiologic cause of CLOAs.

[Parvovirus infections in cats in animal shelters]

Due to widespread vaccination programs against feline panleukopenia virus (FPV), the disease associated with this virus infection, feline panleukopenia, is rarely seen in privately owned cats in Germany. In contrast, the situation in animal shelters differs due to the constant intake of new cats that are often unprotected. In such facilities, panleukopenia outbreaks are common and often accompanied by a high number of fatalities. Due to the high contagiosity of the virus, some shelters do not accept cats with clinical signs suspicious for panleukopenia, since these animals can pose a risk to the shelter population. However, not only cats with panleukopenia shed parvovirus, but also healthy, asymptomatic cats can and thus contribute to risk of infection. Nevertheless, the risk for panleukopenia outbreaks in animal shelters can be reduced by rigorous outbreak management. This includes hygiene measures using correctly applied cleaning and disinfection protocols, quarantine measures, separate isolation units, as well as specific prophylactic measures, such as identification of infected animals and immunization of susceptible groups.

Detection of Selected Canine Viruses in Nigerian Free-Ranging Dogs Traded for Meat Consumption

Animal trade favors the spreading of emerging and re-emerging pathogens. Concerns have been previously expressed regarding the risks of dog trade in spreading zoonotic pathogens in Nigeria. However, the role of these dogs in disseminating highly pathogenic canine viruses has not yet been explored. The present study aimed to identify selected canine viruses in dogs traded for meat consumption in Nigeria. A total of 100 blood samples were screened for carnivore protoparvovirus-1 (CPPV-1), canine adenovirus 1/2 (CAdV-1/2), canine circovirus (CaCV), and canine distemper virus (CDV) by using real-time PCR and conventional PCR and/or sequencing. CPPV-1 DNA was identified in 83% of canine samples while CaCV DNA and CDV RNA were detected in 14% and 17% of the dog samples, respectively. None of the dogs tested positive for CAdV-1/2. The CaCVs identified in this study clustered along with other European, Asian, and American strains. Moreover, CDV strains identified in Nigeria clustered in a separate lineage with the closest genetic relatedness to the Europe-South America-1 clade. Further surveys prior to and after arrival of dogs at the slaughtering points are required to clarify the real virus burden in these animals.

Molecular characterization of carnivore protoparvovirus strains circulating in cats in Turkey

ABSTRACT: Cats are susceptible to feline panleukopenia virus (FPV) and canine parvovirus type 2 (CPV-2). Therefore, coinfection and superinfection with multiple parvovirus strains may occur, resulting in high heterogeneity and recombination. Considering the importance of cats as a potential source of genetic diversity for parvoviruses, we investigated the frequency of parvovirus infection in cats using their blood and fecal samples and performed molecular characterization of parvovirus strains circulating in cat populations. Accordingly, the fecal and blood samples of 60 cats with gastroenteritis symptoms were collected from Turkey’s Burdur, Isparta, and Izmit provinces. Of these 15 fecal samples tested as parvovirus-positive by PCR, 14 were confirmed to have been infected with true FPV strains by sequencing analysis. Through the phylogeny analysis, those were located in the FPV cluster, closely related to CPV-2, and one was discriminated in the CPV-2b cluster. Additionally, sequence analysis of the VP2 gene of CPV and FPV revealed that the FPV strains detected in Turkey and the vaccine strains were highly related to each other, with a nucleotide identity of 97.7- 100%. Furthermore, 13 variable positions were detected in VP2 of the field and reference FPV strains. Three synonymous mutations were determined in the VP2 gene. Some amino acid mutations in the VP2 protein-affected sites were considered responsible for the virus’s biological and antigenic properties. The partial sequence analysis of the VP2 gene revealed that four FPV strains detected in Turkey have a single nucleotide change from T to G at the amino acid position 384 between the nucleotides 3939-3941, which was reported for the first time. Therefore, these four isolates formed a different branch in the phylogenetic tree. The results suggest that both FPV and CPV-2b strains are circulating in domestic cats in Turkey and cats should be considered as potential sources of new parvovirus variants for cats, dogs and other animals.

Characterization of the VP2 and NS1 genes from canine parvovirus type 2 (CPV-2) and feline panleukopenia virus (FPV) in Northern China

Canine parvovirus type 2 (CPV-2) and feline panleukopenia virus (FPV) cause severe disease in young animals, pups, and kittens. CPV-2 evolved from FPV by altering the species-specific binding of the viral capsid to the host receptor, i.e., the transferrin receptor (TfR), and CPV-2 genetic variants have been identified by specific VP2 amino acid residues (297, 426). Early studies focused on the main capsid protein VP2; however, there have been limited studies on the non-structural protein NS1. In this study, we identified the genetic variants of clinical samples in dogs and cats in northern China during 2019-2020. The genetic characterization and phylogenetic analyses of VP2 and NS1 gene were also conducted. The results revealed that the CPV-2c was identified as the major genetic variant. One new CPV-2b and two CPV-2c strains were collected from cats. Four mutation sites (60, 630, 443, and 545 amino acid residues) were located in the functional domains of the NS1 protein. The phylogenetic analysis of VP2 and NS1 genes showed that they were clustered by geographical regions and genotypes. The gene mutation rate of CPV-2 was increasing in recent years, resulting in a complex pattern of gene evolution in terms of host preference, geographical selection, and new genetic variants. This study emphasizes that continuous molecular epidemiological surveillance is required to understand the genetic diversity of FPV and CPV-2 strains.

A Retrospective Study of Viral Molecular Prevalences in Cats in Southern Italy (Campania Region)

From 2019 to 2021, a retrospective molecular study was conducted in the Campania region (southern Italy) to determine the prevalence of viral diseases in domestic cats. A total of 328 dead animals were analyzed by Real-Time PCR for the presence of feline panleukopenia virus (FPV), feline leukemia virus (FeLV), feline enteric coronavirus (FCoV), rotavirus (RVA), feline herpesvirus type 1 (FHV-1), and feline calicivirus (FCV). The possible presence of SARS-CoV-2 was also investigated by Real-Time PCR. The cats included in this study were specifically sourced and referred by local veterinarians and local authorities to the Zooprofilactic Experimental Institute of Southern Italy (IZSM) for pathological evaluation. The samples consisted of owners, catteries, and stray cats. Results revealed: 73.5% positive cats for FPV (189/257), 23.6% for FeLV (21/89), 21.5% for FCoV (56/266), 11.4% for RVA (16/140), 9.05% for FeHV-1 (21/232), and 7.04 for FCV (15/213). In contrast, SARS-CoV-2 was never detected. FPV was more prevalent in winter (p = 0.0027). FCoV FHV-1, FCV, and RVA predominated in autumn, whereas FeLV predominated in summer. As expected, viral infections were found more frequently in outdoor and shelter cats than in indoor ones, although no statistical association was found between animal lifestyle and viral presence. The study showed a high prevalence of FPV, FeLV, and FCoV and a moderate prevalence of RVA, FHV-1, and FCV. Moreover, the prevalence of these pathogens varied among the cat populations investigated.

Persistence of DNA from canine parvovirus modified-live virus in canine tissues

Canine parvovirus (CPV-2) modified-live virus vaccine strain can replicate in lymphoid tissues and intestinal mucosa after administration, being shed through canine faeces. Detection of vaccine strains has been reported in the bloodstream and faeces, potentially interfering with molecular diagnostic tests. The persistence of these strains in canine tissues has not yet been described. With this aim, canine tissues were tested during a molecular survey to screen for the presence of canine enteric viruses. Tissue samples from 165 dead dogs were tested by a conventional PCR assay. Positive samples and five commercial vaccines were subjected to sequence analysis. Vaccinal strains were detected and virus load was measured by using a set of real-time PCR assays using minor-groove binder (MGB) probes. Seventy-five dogs (45.4%) tested positive for CPV-2. Strains from 70 dogs were characterised as field variants. The presence of CPV sequences of vaccine origin was observed in the spleen, intestine, and mesenteric lymph nodes of five young dogs. Vaccinal strains were detected from 12 to 24 days after the last vaccine administration. Viral loads comprised between 6.3 × 10² and 9.95 × 10⁴ DNA copies/10 µl of template. This study confirms that CPV vaccinal strains can be detected in canine tissues after vaccination, so post-mortem diagnosis of CPV infection needs further molecular analyses to assess the viral type (vaccine or field strains). The present study updates the current information on the persistence of CPV vaccine strains in canine tissues and their possible interference with molecular assays.

Molecular characterization of carnivore protoparvovirus 1 circulating in domestic carnivores in Egypt

Canine parvovirus (CPV) and feline panleukopenia virus (FPV), now included in the unique species Carnivore protoparvovirus 1 (CPPV1), have been circulating in dogs and cats for several decades and are considered the causes of clinically important diseases, especially in young animals. While genetic evidence of the circulation of parvoviruses in Egyptian domestic carnivores has been provided since 2016, to date, all available data are based on partial fragments of the VP2 gene. This study reports the molecular characterization of CPPV strains from Egypt based on the full VP2 gene. Overall, 196 blood samples were collected from dogs and cats presented at veterinary clinics for routine medical assessment in 2019 in Egypt. DNA extracts were screened and characterized by real-time PCR. Positive samples were amplified by conventional PCR and then were sequenced. Nucleotide and amino acid changes in the sequences were investigated and phylogeny was inferred. Carnivore protoparvovirus DNA was detected in 18 out of 96 dogs (18.8%) and 7 of 100 cats (7%). Phylogenetic analyses based on the full VP2 gene revealed that 9 sequenced strains clustered with different CPV clades (5 with 2c, 2 with 2a, 1 with 2b, and 1 with 2) and 1 strain with the FPV clade. All three CPV variants were detected in dog and cat populations with a predominance of CPV-2c strains (7 of 18, 38.9%) in dog samples, thus mirroring the circulation of this variant in African, European, and Asian countries. Deduced amino acid sequence alignment revealed the presence of the previously unreported unique mutations S542L, H543Q, Q549H, and N557T in the Egyptian CPV-2c strains.

Carnivore protoparvovirus 1 in Peruvian dogs: Temporal/geographical and evolutionary dynamics of virus

Canine parvovirus (CPV) has been recognized all around the world as the causal agent of a contagious and highly mortal disease in domestic dogs. In Peru, the infection is endemic and unvaccinated animals and puppies are the most at risk. In order to analyze viral diversity and determine the evolutionary genetic relationships and transmission dynamic of Peruvian CPV-2, were collected during the period of 2016-2017 rectal swabs from puppies with parvovirosis compatible symptoms. Viral DNA was amplified by PCR using primers that flanked the ends of the viral genome and sequenced by Illumina Miseq platform. Twenty-six genomic sequences (NSP1-VP1) of CPV from several districts in Lima Metropolitan area were obtained. The VP2 gene analysis demonstrated the presence of the New CPV-2a, New CPV-2b and 2c variants. The phylodynamic analysis of the viral genomes determined that all Peruvian sequences were clustered into a big clade named South American clade that emerged from the west region of Europe (Italy). The Time to the Most Recent Common Ancestor (TMRCA) of the South American clade was dated to 1993. Peruvian sequences were distributed into three subclades, and the 92% of these sequences were related to Ecuadorian CPV-2. The results suggests that three independent introduction events of virus from other countries could have occurred, in two of these events, CPV-2 from Ecuador were introduced in Peru in 2003 and 2009, and another introduction event, in 2000, from Europe. Overall, these results indicate a viral genetic relationship between Peruvian with Ecuadorian and European virus, and the circulation of several viral subpopulations in Lima Metropolitan.

Feline Morbillivirus in Southern Italy: Epidemiology, Clinico-Pathological Features and Phylogenetic Analysis in Cats

Feline morbillivirus (FeMV) was isolated for the first time in 2012 with an association with chronic kidney disease (CKD) suggested. This study aimed at investigating in cats from southern Italy FeMV prevalence and risk factors for exposure to FeMV, including the relationship with CKD; sequencing amplicons and analyzing phylogeny of PCR positive samples. Blood serum, K₃EDTA blood and urine samples from 223 cats were investigated. Ten carcasses were also evaluated. FeMV RNA was detected in 2.4% (5/211) blood and 16.1% (36/223) urine samples. One carcass tested positive by qPCR_FeMV from kidney, urinary bladder, and submandibular lymph nodes. Antibodies against FeMV were detected in 14.5% (28/193) cats. We followed up 27 cats (13 FeMV positive cats) and documented in some cases urine shedding after up to 360 days. Older and foundling cats and cats living in rescue catteries, were more frequently infected with FeMV. A significant correlation between FeMV and higher serum creatinine values or low urine specific gravity was found. FeMV positivity was significantly associated with retroviral infection, and the presence of some clinical signs apart from CKD clinicopathological markers. Our study highlights the possibility of a link between FeMV exposure and CKD and a general impairment of feline health.

A virtual biobank for companion animals: A parvovirus pilot study

BACKGROUND

There is a lack of national population data concerning infectious disease in companion animals. Here, we piloted the feasibility of linking diagnostic laboratories, population surveillance and modern sequencing approaches to extract targeted diagnostic samples from laboratories before they were discarded, as a novel route to better understand national epidemiology of major small animal pathogens.

METHODS

Samples tested for canine or feline parvovirus were requested from a national veterinary diagnostic laboratory and analysed by Sanger or next generation sequencing. Samples were linked to electronic health data held in the SAVSNET database.

RESULTS

Sequences obtained from positive samples, together with associated metadata, provided new insights into the recent geographical distribution of parvovirus strains in circulation in the United Kingdom (UK).

CONCLUSIONS

This collaboration with industry represents a 'National Virtual Biobank' that can rapidly be called on, to efficiently add new layers of epidemiological information of relevance to animal, and potentially human, population health.

Emerging Parvoviruses in Domestic Cats

Parvovirus infections in cats have been well known for around 100 years. Recently, the use of molecular assays and metagenomic approaches for virus discovery and characterization has led to the detection of novel parvovirus lineages and/or species infecting the feline host. However, the involvement of emerging parvoviruses in the onset of gastroenteritis or other feline diseases is still uncertain.

Genetic Insights into Feline Parvovirus: Evaluation of Viral Evolutionary Patterns and Association between Phylogeny and Clinical Variables

Feline panleukopenia is a severe disease of cats caused by feline parvovirus (FPV), and marginally canine parvovirus (CPV). Despite being less rapid than CPV, FPV evolution deserves attention, especially since outbreaks of particular severity are currently reported. This apparently different virulence needs monitoring from genetic and clinical points of view. This manuscript explored FPV molecular epidemiology at both Italian and international levels and the possible association between viral phylogeny and disease severity. Sequences from clinical cases of feline panleukopenia in Italy were obtained from 2011 to 2019, and the etiological agent was characterized, distinguishing FPV from CPV. Phylogenetic and phylodynamic analyses were conducted on Italian and international sequences. Moreover, the association between the viral sequence and clinical variables was evaluated on a group of highly characterized patients. After its origin in the 1920s, FPV showed a constant population size until a more recent expansion since 2000. Few long-distance introduction events characterized FPV spreading, however, most of its evolution occurred locally. Although without a strong statistical association, several clinical variables appeared influenced by viral phylogeny, suggesting a differential virulence potentially characterizing FPV strains. These results stress the importance of the continuous study of viral evolution and its repercussions on the disease clinical aspects.

Molecular Epidemiological Survey of Canine Parvovirus Circulating in China from 2014 to 2019

The global distribution of canine parvovirus (CPV-2) derived from a closely related carnivore parvovirus poses a considerable threat to the dog population. The virus is continuously undergoing genetic evolution, giving rise to several variants. To investigate the prevalence of Chinese CPV-2 strains in recent years, a total of 30 CPV-2 strains were collected from 2018 to 2021 and the VP2 gene was sequenced and analyzed. Two variants, new CPV-2a (297Ala, 426Asn) and CPV-2c (426Glu), were identified. In contrast to previous reports, the CPV-2c variant has gained an epidemiological advantage over the new CPV-2a variant in China. To compensate for the relatively small sample size, 683 Chinese CPV-2 strains identified between 2014 and 2019 were retrieved from the GenBank database and previous publications, and analyses of these strains further supported our findings, which should be considered since the CPV-2c variant has been frequently associated with immune failure in adult dogs. VP2 protein sequence analysis revealed several amino acid substitutions, including Ala5Gly, Pro13Ser, Phe267Tyr, Tyr324Ile, Gln370Arg, Thr440Ala, and Lys570Arg. Phylogenetic analysis of full-length VP2 gene indicated a close relationship between Chinese strains and other Asian strains, suggesting mutual transmission between Asian countries. Furthermore, intercontinental transmission is a cause for concern. Surprisingly, two feline panleukopenia virus (FPV) strains with the Ile101Thr mutation in the VP2 protein were identified in canine fecal samples; FPV has been considered incapable of infecting dogs. This study clarified the epidemic characteristics of Chinese CPV-2 strains detected between 2014 and 2019, offering a reference for epidemic control. In addition, the detection of FPV in canine samples may provide information for future studies on the evolution of carnivore parvoviruses.

Genetic Characterization of Feline Parvovirus Isolate Fe-P2 in Korean Cat and Serological Evidence on Its Infection in Wild Leopard Cat and Asian Badger

Feline parvovirus (FPV) is a small, non-enveloped, single-stranded DNA virus that infects cats. We recently isolated a feline parvovirus Fe–P2 strain from a dead stray cat in Iksan, 2017. Its partial genomic sequence (4,643 bases) was obtained, and phylogenetic analysis based on the VP2 nucleotide sequence showed that the FPV Fe-P2 strain was closely related to the FPV isolate Gigucheon in cat, 2017 (MN400978). In addition, we performed a serum neutralization (SN) test with the FPV isolates in various mammalian sera. These were from raccoon dog, water deer, Eurasian otter, Korean hare, leopard cat, and Asian badger, which were kindly provided by Chungnam Wild Animal Rescue Center. Notably, serological evidence of its infection was found in Asian badger, Meles leucurus (2/2) and leopard cat, Prionailurus bengalensis (5/8) through SN tests, whereas there was no evidence in raccoon dog, water deer, Eurasian otter, and Korean hare based on the collected sera in this study. These findings might provide partial evidence for the possible circulation of FPV or its related viruses among wild leopard cat and Asian badger in Korea. There should be additional study to confirm this through direct detection of FPVs in the related animal samples.

Molecular survey of parvovirus, astrovirus, coronavirus, and calicivirus in symptomatic dogs

Gastrointestinal disorders caused by enteric viruses are frequently reported in dogs worldwide, with significant mortality rates in unvaccinated individuals. This study reports the identification and molecular characterization of Canine parvovirus (CPV-2), Canine coronavirus (CcoV), Canine astrovirus (AstV), and Canine calicivirus (CcaV) in a panel of dogs showing severe enteric clinical signs sampled in a typical Mediterranean environment (Sardinia, Italy). At least one of these viral species was detected in 92.3% samples. CPV-2 was the most frequently detected virus (87.2%), followed by AsTv (20.5%), CCoV-IIa (18%), and CCoV-I (10.3%). CCoV-IIb and CaCV were not detected in any sample. Single infection was detected in 24 samples (66.7%), mainly related to CPV-2 (91.7%). Coinfections were present in 33.3% samples with constant detection of CPV-2. Canine coronavirus was present only in coinfected animals. The VP2 sequence analysis of CPV-2 positive samples confirmed the presence of all variants, with CPV-2b most frequently detected. Phylogeny based on the CcoV-IIa spike protein (S) gene allowed to identify 2 different clades among Sardinian isolates but failed to distinguish enteric from pantropic viruses. Study on presence and prevalence of enteroviruses in dogs increase our knowledge about the circulation of these pathogens in the Mediterranean area and highlight the need for dedicated routine vaccine prophylaxis. Molecular analyses of enteric viruses are fundamental to avoid failure of vaccines caused by frequent mutations observed in these enteroviruses.

Circulation of diverse protoparvoviruses in wild carnivores, Italy

Protoparvovirus is a monophyletic viral genus that includes the species Carnivore protoparvovirus-1 infecting domestic and wild carnivores. In this paper, the results of an epidemiological survey for Carnivore protoparvovirus-1 in wild carnivores in Italy are reported. Overall, 34 (11.4%) out of 297 tested animals were positive for Carnivore protoparvovirus-1, but the frequency of detection was much higher in intestine (54%) than in spleen samples (2.8%), thus suggesting that the intestine is the best sample to collect from wild animals for parvovirus detection. Feline panleukopenia virus (FPV) was detected in red foxes (Vulpes vulpes) (2.8%, 7/252) and Eurasian badgers (Meles meles) (10%, 1/10), whilst canine parvovirus (CPV) was found in wolves (54.3%, 19/35), Eurasian badgers (60%, 6/10) and one beech marten (Martes foina) (100%, 1/1), with more than one parvovirus type detected in some animals. Protoparvoviral DNA sequences from this study were found to be related to CPV/FPV strains detected in Asia and Europe, displaying some amino acid changes in the main capsid protein VP2 in comparison with other parvovirus strains from wildlife. In particular, the two most common mutations were Ile418Thr and Ala371Gly, which were observed in 6/12 (50%) and 5/12 (41.7%) of the CPV sequences from this study. Continuous surveillance for parvoviruses in wild carnivores and genetic analysis of the detected strains may help obtain new insight into the role of these animals in the evolution and epidemiology of carnivore parvoviruses.

Genetic characterization of feline panleukopenia virus from dogs in Vietnam reveals a unique Thr101 mutation in VP2

Background

Canine parvovirus type 2 (CPV-2) and feline parvovirus (FPV) are known as the main causes of several serious diseases and have a severe impact on puppies and kittens, respectively. FPV and new CPV-2 variants are all able to infect cats, causing diseases indistinguishable from feline panleukopenia. However, FPV only replicates efficiently in feline cells in vitro and replicates in dogs in the thymus and bone marrow without being shed in feces. In our previous study, the genotypes of six parvoviral isolates were unable to be identified using a SimpleProbe^® real-time PCR assay.

Methods

In the present study, we characterized previously unidentified FPV-like viruses isolated from dogs in Vietnam. The six isolates were utilized to complete VP2 gene sequencing and to conduct phylogenetic analyses.

Results

Sequence analysis of the six parvoviral strains identified the species as being similar to FPV. Phylogenetic analysis demonstrated that the complete VP2 genes of the strains are similar to those of FPV. The FPV-like strains contain a Thr101 mutation in the VP2 protein, which is different from prototype FPV strains.

Discussion

Our data provide evidence for the existence of changes in the charge, protein contact potential and molecular surface of the core of the receptor-binding size with an Ile101 to Thr101 mutation. This is also the first study to provide reliable evidence that FPV may be a threat to the Vietnamese dog population.

The increasing prevalence of CPV-2c in domestic dogs in China

Background

Canine parvovirus type 2 (CPV-2), a serious pathogen, leads to high morbidity and mortality in dogs and several wild carnivore species. Although it is a DNA virus, it evolves particularly rapidly, with a genomic substitution rate of approximately 10⁻⁴ substitutions/site/year, close to that of some RNA viruses. Tracing the prevalence of CPV-2 in dogs is significant.

Methods

In this study, an aetiological survey was carried out from 2016 to 2019 in Guangdong Province, China, involving Guangzhou, Shenzhen and Dongguan. Furthermore, to systematically analyse the prevalence of CPV-2 in China, the VP2 gene sequences of all Chinese isolates were downloaded from the NCBI nucleotide database in December 2019, and changes in CPV-2 variants were examined.

Results

A total of 55.7% (34/61) of samples were CPV-2 positive by PCR detection and virus isolation. In addition to different variants circulating in dogs, coinfection with multiple variants was identified, as was coinfection with other canine enteric pathogens in some cases. Two previously reported amino acid sites, A5G and Q370R of CPV-2c mutants, reported in variants in China were assessed, and several CPV-2 isolates with P13S and K582N mutations were detected in this study. Finally, we speculate on the prevalence of different CPV-2 variants in China. According to the VP2 gene sequence obtained from the NCBI nucleotide database, the proportion of different variants in China has changed, and CPV-2c appears to be growing rapidly. In conclusion, this aetiology survey suggests that CPV-2 continues to be common in China and that the prevalence of CPV-2c is increasing.

Molecular characteristics of the capsid protein VP2 gene of canine parvovirus type 2 amplified from raccoon dogs in Hebei province, China

Canine parvovirus type 2 (CPV-2) is currently circulating in domestic and wild animals, but our knowledge about CPV-2 infections in raccoon dogs is limited. In this study, VP2 gene sequences of CPV-2 were amplified from rectal swabs of 14 diarrhetic raccoon dogs (Nyctereutes procyonoides) in Hebei province, China, in 2016 and 2017. Phylogenetic analysis of the VP2 gene sequences revealed that most of these sequences (11 of 14) belonged to the same subclade as raccoon dog strain CPV-2/Raccoon_Dog/China/DP-1/16 isolated from Shandong province in 2016. A comparison of deduced amino acid sequences revealed presence of the substitutions S297A and S27T in 11 of those 14 sequences. I418T was observed in a minority of the sequences (4 of 14). In addition, A300D and T301I, P13S and I219V, and N419K were found in three of the sequences. This study shows that CPV-2 strains with different substitutions in their VP2 amino acid sequences were spreading among raccoon dogs in Hebei during 2016 and 2017 and suggests that further studies are needed to monitor the distribution of these strains in China.

Analysis of canine parvoviruses circulating in Australia reveals predominance of variant 2b and identifies feline parvovirus-like mutations in the capsid proteins

Canine parvovirus (CPV) is a major enteric pathogen of dogs worldwide that emerged in the late 1970s from a feline parvovirus (FPV)-like ancestral virus. Shortly after its emergence, variant CPVs acquired amino acid (aa) mutations in key capsid residues, associated with biological and/or antigenic changes. This study aimed to identify and analyse CPV variants and their capsid mutations amongst Australian dogs, to gain insights into the evolution of CPV in Australia and to investigate relationships between the disease and vaccination status of dogs from which viruses were detected. CPV VP2 sequences were amplified from 79 faecal samples collected from dogs with parvoviral enteritis at 20 veterinary practices in five Australian states. The median age at diagnosis was 4 months (range 1-96 months). Only 3.7% of dogs with vaccination histories had completed recommended vaccination schedules, while 49% were incompletely vaccinated and 47.2% were unvaccinated. For the first time, CPV-2b has emerged as the dominant antigenic CPV variant circulating in dogs with parvoviral enteritis in Australia, comprising 54.4% of viruses, while CPV-2a and CPV-2 comprised 43.1% and 2.5%, respectively. The antigenic variant CPV-2c was not identified. Analysis of translated VP2 sequences revealed a vast repertoire of amino acid (aa) mutations. Several Australian CPV strains displayed signatures in the VP2 protein typical of Asian CPVs, suggesting possible introduction of CPV strains from Asia, and/or CPV circulation between Asia and Australia. Canine parvoviruses were identified containing aa residues typical of FPV at key capsid (VP2) positions, representing reverse mutations or residual mutations retained from CPV-2 during adaptation from an FPV-like ancestor, suggesting that evolutionary intermediates between CPV-2 and FPV are circulating in the field. Similarly, intermediates between CPV-2a-like viruses and CPV-2 were also identified. These findings help inform a better understanding of the evolution of CPV in dogs.

Cellular microRNA, miR-1343-5p, modulates IFN-I responses to facilitate feline panleukopenia virus replication by directly targeting IRAK1 gene

Feline panleukopenia is an acute, highly contagious, and fatal infectious disease caused by feline panleukopenia virus (FPV) and has led to severe consequences on pets, economically important animals, and the wildlife industry. MicroRNAs (miRNAs) play significant roles in the host-pathogen interaction by modulating cellular factors expression which are essential for viral replication or host innate immune response to infection. However, the role of host miRNA response in FPV infection remains to be discovered. In this study, we screened nine host miRNAs associated with FPV infection that were previously implicated in innate immunity or antiviral functions. We found that miR-1343-5p overexpression strongly promoted FPV-BJ04 genomic DNA. Subsequently, the expression of host miR-1343-5p was upregulated by FPV-BJ04 infection in vitro and in vivo. In addition, we demonstrated that miR-1343-5p was a negative regulator of the IFN-I signaling pathway, thereby promoting FPV infection. Bioinformatic analysis combined with molecular biological assay indicated that interleukin-1 receptor-associated kinase 1 (IRAK1) is a putative target of miR-1343-5p. Collectively, our findings emphasize the importance of miR-1343-5p in host defense against FPV, thus, enhancing our understanding of its pathogenic mechanism.

Regional adaptations and parallel mutations in Feline panleukopenia virus strains from China revealed by nearly-full length genome analysis

Protoparvoviruses, widespread among cats and wild animals, are responsible for leukopenia. Feline panleukopenia virus (FPLV) in domestic cats is genetically diverse and some strains may differ from those used for vaccination. The presence of FPLV in two domestic cats from Hebei Province in China was identified by polymerase chain reaction. Samples from these animals were used to isolate FPLV strains in CRFK cells for genome sequencing. Phylogenetic analysis was performed to compare our isolates with available sequences of FPLV, mink parvovirus (MEV) and canine parvovirus (CPV). The isolated strains were closely related to strains of FPLV/MEV isolated in the 1960s. Our analysis also revealed that the evolutionary history of FPLV and MEV is characterized by local adaptations in the Vp2 gene. Thus, it is likely that new FPLV strains are emerging to evade the anti-FPLV immune response.

Distinct Lineages of Feline Parvovirus Associated with Epizootic Outbreaks in Australia, New Zealand and the United Arab Emirates

Feline panleukopenia (FPL), a frequently fatal disease of cats, is caused by feline parvovirus (FPV) or canine parvovirus (CPV). We investigated simultaneous outbreaks of FPL between 2014 and 2018 in Australia, New Zealand and the United Arab Emirates (UAE) where FPL outbreaks had not been reported for several decades. Case data from 989 cats and clinical samples from additional 113 cats were obtained to determine the cause of the outbreaks and epidemiological factors involved. Most cats with FPL were shelter-housed, 9 to 10 weeks old at diagnosis, unvaccinated, had not completed a primary vaccination series or had received vaccinations noncompliant with current guidelines. Analysis of parvoviral VP2 sequence data confirmed that all FPL cases were caused by FPV and not CPV. Phylogenetic analysis revealed that each of these outbreaks was caused by a distinct FPV, with two virus lineages present in eastern Australia and virus movement between different geographical locations. Viruses from the UAE outbreak formed a lineage of unknown origin. FPV vaccine virus was detected in the New Zealand cases, highlighting the difficulty of distinguishing the co-incidental shedding of vaccine virus in vaccinated cats. Inadequate vaccination coverage in shelter-housed cats was a common factor in all outbreaks, likely precipitating the multiple re-emergence of infection events.

Molecular epidemiology of canine parvovirus type 2 in Italy from 1994 to 2017: recurrence of the CPV-2b variant

Background

Canine parvovirus type 2 (CPV-2) is the most important enteric virus infecting canids. It is a rapidly evolving virus; after its emergence in the 1970s, new antigenic variants (called CPV-2a, 2b and 2c) emerged and replaced the original antigenic type. The three antigenic variants are globally distributed with different frequencies and levels of genetic variability. This study focused on VP2 gene sequence analysis and the phylodynamics of CPV-2 which were detected in 123 dogs showing clinical signs of gastroenteritis collected in Italy from 1994 to 2017.

Results

For the most part, the sick dogs were young, and a third of them (32.5%) had been vaccinated. No statistical association was found between the CPV-2 antigenic variants, and sex, age, breed and vaccination status. Sequence analysis showed that all three antigenic types circulated in Italy; the CPV-2a type was the prominent genotype, followed by CPV-2c and CPV-2b, with notable differences regarding regional bases and significant fluctuations over time. Nucleotide sequence data showed high genetic heterogeneity with 67 nucleotide sequence types (ntSTs) identified, corresponding to 21 amino acid sequence types (aaSTs). The aaSTs and ntSTs obtained were distributed differently among the three CPV-2 antigenic variants: CPV-2a grouped 12/21 (57.1%) aaSTs and 41/67 (61.2%) ntSTs; CPV-2b grouped 5/21 (23.8%) aaSTs and 6/67 (8.9%) ntSTs, and CPV-2c grouped 4/21 (19.1%) aaSTs and 20/67 (29.9%) ntSTs. Canine parvovirus 2a was characterised by the highest genetic variability while CPV-2c was characterised by notable stability with a predominant amino acid profile during the entire sampling time. Canine parvovirus 2b re-emerged in recent years, showing a new and distinctive amino acid profile of the VP2 protein.

Conclusions

The findings of the present study provided new insights regarding the phylodynamics and evolution of CPV-2 in Italy, pointing out notable differences at the local level in the distribution of the CPV-2 variants and the selection of genetic subtypes. The evolution of CPV-2 has raised questions regarding the efficacy of vaccination; therefore, continuous monitoring regarding the evolution and spread of new CPV-2 variants should be a key aim of ongoing research.

Isolation and identification of tiger parvovirus in captive siberian tigers and phylogenetic analysis of VP2 gene

To better understand the prevalence and molecular epidemiology of parvovirus, this study reports the isolation and characterization of a tiger parvovirus (TPV) named CHJL-Siberian Tiger-01/2017 from a captive Siberian tiger in Jilin Province, China. A phylogenetic tree based on the full-length VP2 nucleotide sequence was constructed using the isolated strain in this study and 56 reference strains. The results showed that all the parvoviruses can be grouped into two large branches: the canine parvovirus (CPV) branch and the feline parvovirus (FPV) branch. FPV strains comprised TPVs, FPVs, blue fox parvoviruses (BFPVs), mink enteritis viruses (MEVs), and raccoon feline parvoviruses (RFPVs), and CPV strains comprised CPVs and raccoon dog parvoviruses (RDPVs). RFPVs are also often very closely related to those sampled from other carnivorous species, and raccoons may represent conduits for parvovirus transmission to other hosts. The results of amino acid changes in the VP2 protein of the isolated strain showed that amino acid Ile 101 was mutated to Thr (I 101T). Taken together, a field TPV strain CHJL-Siberian Tiger-01/2017 was isolated, which may be suitable for future studies on FPV infection, replication and vaccine development. This study provided new important findings about the evolution of parvovirus infection in tigers.

Carnivore Parvovirus Ecology in the Serengeti Ecosystem: Vaccine Strains Circulating and New Host Species Identified

Carnivore parvoviruses infect wild and domestic carnivores, and cross-species transmission is believed to occur. However, viral dynamics are not well understood, nor are the consequences for wild carnivore populations of the introduction of new strains into wild ecosystems. To clarify the ecology of these viruses in a multihost system such as the Serengeti ecosystem and identify potential threats for wildlife conservation, we analyzed, through real-time PCR, 152 samples belonging to 14 wild carnivore species and 62 samples from healthy domestic dogs. We detected parvovirus DNA in several wildlife tissues. Of the wild carnivore and domestic dog samples tested, 13% and 43%, respectively, were positive for carnivore parvovirus infection, but little evidence of transmission between the wild and domestic carnivores was detected. Instead, we describe two different epidemiological scenarios with separate routes of transmission: first, an endemic feline parvovirus (FPV) route of transmission maintained by wild carnivores inside the Serengeti National Park (SNP) and, second, a canine parvovirus (CPV) route of transmission among domestic dogs living around the periphery of the SNP. Twelve FPV sequences were characterized; new host-virus associations involving wild dogs, jackals, and hyenas were discovered; and our results suggest that mutations in the fragment of the vp2 gene were not required for infection of different carnivore species. In domestic dogs, 6 sequences belonged to the CPV-2a strain, while 11 belonged to the CPV-2 vaccine-derived strain. This is the first description of a vaccine-derived parvovirus strain being transmitted naturally.IMPORTANCE Carnivore parvoviruses are widespread among wild and domestic carnivores, which are vulnerable to severe disease under certain circumstances. This study furthers the understanding of carnivore parvovirus epidemiology, suggesting that feline parvoviruses are endemic in wild carnivores in the Serengeti National Park (SNP), with new host species identified, and that canine parvoviruses are present in the dog population living around the SNP. Little evidence of transmission of canine parvoviruses into wild carnivore species was found; however, the detection of vaccine-derived virus (described here for the first time to be circulating naturally in domestic dogs) highlights the importance of performing epidemiological research in the region.

Analysis of the microRNA expression profiles in feline kidney cell line infected with feline panleukopenia virus

MicroRNAs (miRNAs) play crucial roles in post-transcriptional regulation of gene expression in many biological processes. Feline panleukopenia virus (FPV) is a highly infectious pathogen that can cause severe disease in pets, economically important animals and wildlife. In this study, miRNAs associated with FPV infection were identified using high-throughput sequencing. Our results showed that 673 known miRNAs and 278 novel miRNAs were identified and 57 significantly differential expression miRNAs were found post-FPV infection in feline kidney cell line. Stem-loop qRT-PCR was applied to validate the expression of the randomly selected miRNAs; the results were consistent with the sequencing data. Furthermore, the target genes of differential expression miRNAs were analyzed and predicated by GO and KEGG pathway. Altogether, our analysis provides a potential link between miRNA expression and the pathogenesis of FPV infection.

Carnivore Parvovirus Ecology in the Serengeti Ecosystem: Vaccine Strains Circulating and New Host Species Identified

Carnivore parvoviruses infect wild and domestic carnivores, and cross-species transmission is believed to occur. However, viral dynamics are not well understood, nor are the consequences for wild carnivore populations of the introduction of new strains into wild ecosystems. To clarify the ecology of these viruses in a multihost system such as the Serengeti ecosystem and identify potential threats for wildlife conservation, we analyzed, through real-time PCR, 152 samples belonging to 14 wild carnivore species and 62 samples from healthy domestic dogs. We detected parvovirus DNA in several wildlife tissues. Of the wild carnivore and domestic dog samples tested, 13% and 43%, respectively, were positive for carnivore parvovirus infection, but little evidence of transmission between the wild and domestic carnivores was detected. Instead, we describe two different epidemiological scenarios with separate routes of transmission: first, an endemic feline parvovirus (FPV) route of transmission maintained by wild carnivores inside the Serengeti National Park (SNP) and, second, a canine parvovirus (CPV) route of transmission among domestic dogs living around the periphery of the SNP. Twelve FPV sequences were characterized; new host-virus associations involving wild dogs, jackals, and hyenas were discovered; and our results suggest that mutations in the fragment of the vp2 gene were not required for infection of different carnivore species. In domestic dogs, 6 sequences belonged to the CPV-2a strain, while 11 belonged to the CPV-2 vaccine-derived strain. This is the first description of a vaccine-derived parvovirus strain being transmitted naturally.IMPORTANCE Carnivore parvoviruses are widespread among wild and domestic carnivores, which are vulnerable to severe disease under certain circumstances. This study furthers the understanding of carnivore parvovirus epidemiology, suggesting that feline parvoviruses are endemic in wild carnivores in the Serengeti National Park (SNP), with new host species identified, and that canine parvoviruses are present in the dog population living around the SNP. Little evidence of transmission of canine parvoviruses into wild carnivore species was found; however, the detection of vaccine-derived virus (described here for the first time to be circulating naturally in domestic dogs) highlights the importance of performing epidemiological research in the region.

Feline Panleukopenia: A Re-emergent Disease

Feline panleukopenia (FPL) is caused by a Carnivore protoparvovirus infection. Feline parvovirus (FPV) causes most cases. When Canine parvovirus 2 (CPV-2) first emerged, it could not replicate in cats. All current CPV variants (CPV-2a-c) can infect cats to cause subclinical disease or FPL. Feline panleukopenia has re-emerged in Australia in shelter cats associated with failure to vaccinate. Parvoviruses can remain latent in mononuclear cells post-infection. Molecular methods such as polymerase chain reaction are used to determine the infecting strain. Current perspectives on causes, epidemiology, diagnosis, treatment, prognostic indicators, and management of outbreaks in shelters are reviewed.

Molecular Characterization and Evolutionary Analyses of Carnivore Protoparvovirus 1 NS1 Gene

Carnivore protoparvovirus 1 is the etiological agent of a severe disease of terrestrial carnivores. This unique specie encompasses canine parvovirus type 2 (CPV-2) and feline panleukopenia virus (FPLV). Studies widely analyzed the main capsid protein (VP2), but limited information is available on the nonstructural genes (NS1/NS2). This paper analyzed the NS1 gene sequence of FPLV and CPV strains collected in Italy in 2009–2017, along with worldwide related sequences. Differently from VP2, only one NS1 amino-acid residue (248) clearly and constantly distinguished FPLV from CPV-2, while five possible convergent amino-acid changes were observed that may affect the functional domains of the NS1. Some synonymous mutation in NS1 were non-synonymous in NS2 and vice versa. No evidence for recombination between the two lineages was found, and the predominance of negative selection pressure on NS1 proteins was observed, with low and no overlap between the two lineages in negatively and positively selected codons, respectively. More sites were under selection in the CPV-2 lineage. NS1 phylogenetic analysis showed divergent evolution between FPLV and CPV, and strains were clustered mostly by country and year of detection. We highlight the importance of obtaining the NS1/NS2 coding sequence in molecular epidemiology investigations.

Development of a reverse genetics system for a feline panleukopenia virus

Feline panleukopenia virus (FPV) infects cats and can be fatal to kittens. There is evidence that canine parvovirus originated from FPV, which makes FPV important in studies of the family Parvoviridae. In the present study, the entire genome of FPV strain HH-1/86 was converted into a full-length infectious clone (pFPV). The FPV strain HH-1/86 has a 5123-nt single stranded DNA genome with a Y-shaped inverted 3' terminal repeat (ITR) and a U-shaped inverted 5' ITR. Feline kidney cells (F81) were transfected with the pFPV clone which contained a genetic marker, and a rescued virus was obtained (rFPV). The rFPV was identified by its cytopathic effects, indirect immunofluorescence, growth curve analysis, western blot assay and hemagglutination, and was indistinguishable from the parent virus. The FPV infectious clone will facilitate the study of pathogenicity and viral replication of FPV and the inter-species transmission of parvoviruses.

Research on viral agents associated with feline reproductive problems reveals a high association with feline panleukopenia virus

Although reproductive failures (RF) such as abortion, stillbirth and neonatal mortality in cats are still under researched, it is known that many RF are caused by viral agents. This research surveyed the viral agent prevalence in queens with RF. Queens were excluded from the study if their RF was caused by issues other than infection, such as genetic, traumatic, hormonal or nutritional problems, or if they had a history of RF. Blood samples from 26 pregnant females with RF were collected for complete blood counts (BCC), renal/hepatic biochemistry and glycaemic analysis. Ultrasonography was performed to evaluate gestational age and foetal viability. When possible, placentas, humours and foetal tissues were collected. Blood samples were tested by PCR and qPCR for feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), feline alphaherpesvirus 1 (FeHV-1) and carnivore protoparvovirus 1 (CPPV-1). All maternal samples were negative for FeLV, FIV and FeHV-1 and positive for CPPV-1. In addition, foetuses from one queen and three females were positive for CPPV-1 by qPCR and for feline panleukopenia virus (FPV) through DNA sequencing. The BCC and biochemistry results revealed significant neutrophilia, lymphopenia, monocytosis, and liver enzymes. These results provide the first description of an FPV agent causing only RF-related clinical signs in queens.

Epidemiology and diagnosis of feline panleukopenia virus in Egypt: Clinical and molecular diagnosis in cats

Aim:

This work aimed to study epidemiology and diagnosis of feline panleukopenia virus (FPV) using clinical examination, direct ELISA, RNA viral isolation and identification, and knowing phylogenetic tree of our isolate.

Materials and Methods:

One hundred and sixty-five cats of different ages and sex were examined. Each cat was examined clinically to detect the clinical manifestations of the disease showing symptoms suggestive of feline panleukopenia (FP) as well as ELISA, and polymerase chain reaction (PCR) amplification analyses were conducted.

Results:

Our finding includes (a) clinical signs detected in 165 of 165 cats were in the form of lethargy, fever, anorexia, thirst, vomiting, diarrhea, dehydration, and leukopenia. (b) ELISA results revealed that 66 of all examined cats were positive for FPV. (c) The amplification products from all positive samples were confirmed as FPV (VP1) gene by nucleotide sequences analysis, in which 75 samples were positive using PCR amplification for the FPV. (d) Statistical evaluation of ELISA results in comparison to PCR findings. ELISA showed 88%, 100%, and 94.5% for sensitivity, specificity, and accuracy, respectively, while the prevalence of FP among the examined population was 45%. No effect of sex, breed, and age on ELISA results as recorded using Chi-square analysis.

Conclusion:

The results of the sequence analysis indicated that PCR products of the FPV cDNA exhibited very low variation in their nucleotide sequence of all isolates compared with the published FPV genome, which could be suggested that FPV appears to be genomically stasis compared with other Parvoviruses. The genome sequence of FPLV strain in this study has been deposited in GenBank under the accession number KY466003. Our isolate closely related 100% to isolates from Portugal, which might be the origin of infection to Egypt through importation of cats.

Molecular analysis of carnivore Protoparvovirus detected in white blood cells of naturally infected cats

Background

Cats are susceptible to feline panleukopenia virus (FPV) and canine parvovirus (CPV) variants 2a, 2b and 2c. Detection of FPV and CPV variants in apparently healthy cats and their persistence in white blood cells (WBC) and other tissues when neutralising antibodies are simultaneously present, suggest that parvovirus may persist long-term in the tissues of cats post-infection without causing clinical signs. The aim of this study was to screen a population of 54 cats from Sardinia (Italy) for the presence of both FPV and CPV DNA within buffy coat samples using polymerase chain reaction (PCR). The DNA viral load, genetic diversity, phylogeny and antibody titres against parvoviruses were investigated in the positive cats.

Results

Carnivore protoparvovirus 1 DNA was detected in nine cats (16.7%). Viral DNA was reassembled to FPV in four cats and to CPV (CPV-2b and 2c) in four cats; one subject showed an unusually high genetic complexity with mixed infection involving FPV and CPV-2c. Antibodies against parvovirus were detected in all subjects which tested positive to DNA parvoviruses.

Conclusions

The identification of FPV and CPV DNA in the WBC of asymptomatic cats, despite the presence of specific antibodies against parvoviruses, and the high genetic heterogeneity detected in one sample, confirmed the relevant epidemiological role of cats in parvovirus infection.

Feline Panleukopenia Virus Is Not Associated With Myocarditis or Endomyocardial Restrictive Cardiomyopathy in Cats

Canine parvovirus-2 (CPV-2) is nearly indistinguishable from feline panleukopenia virus (FPV) and is a well-known cause of viral myocarditis in young puppies; however, it is not known whether either FPV or CPV-2 naturally infects feline cardiomyocytes and causes myocarditis. Endomyocarditis (EMC) and left ventricular endomyocardial fibrosis (LVEF), clinically known as "endomyocardial restrictive cardiomyopathy," are important feline heart diseases suspected to have an infectious etiology. A continuum is suggested with EMC representing the acute reaction to an unknown infectious agent and LVEF the chronic manifestation of repair. The purpose of this study was to determine (1) whether there is natural parvovirus infection of the feline myocardium and (2) whether parvoviral infection is associated with feline EMC and/or LVEF. In a retrospective study, polymerase chain reaction and sequencing for the parvovirus VP1/2 gene was performed on archived heart tissue from cats with endomyocardial disease and controls. Similar methods were used prospectively on myocardial tissues from shelter-source kittens. Although 8 of 36 (22%; 95% confidence interval [CI], 11%-40%) shelter kittens had parvoviral DNA in myocardial tissue, VP1/2 DNA was not detected in 33 adult cases or 34 controls (95% CI, 0% to ∼11%). These findings were confirmed by in situ hybridization: adult cats did not have detectable parvovirus DNA, although rare intranuclear signal was confirmed in 7 of 8 shelter-source kittens. In kittens, parvovirus was not significantly associated with myocarditis, and in situ hybridization signal did not colocalize with inflammation. Although infection of cardiomyocytes was demonstrated in kittens, these data do not support a role for parvovirus in EMC-LVEF.

Canine parvoviral enteritis: an update on the clinical diagnosis, treatment, and prevention

Canine parvovirus type 2 is the cause of a highly contagious acute enteritis associated with high morbidity and mortality, with very low survival rates in untreated dogs. Although severe clinical disease typically occurs in dogs younger than 6 months of age, adults with insufficient immunity may potentially be affected. In this article, the current state of knowledge is reviewed regarding the diagnostic aspects of parvoviral enteritis, with special emphasis placed on the clinical relevance of the detection of viral antigens in the feces, detection of viral antibodies in the serum, or the polymerase chain reaction-based amplification of the viral DNA in the feces. In addition, the components of the supportive and symptomatic treatment aiming to optimize the outcome of the disease in the clinical setting are thoroughly reviewed. Immunization guidelines for the prevention of the disease are also updated.

A Ten-Year Molecular Survey on Parvoviruses Infecting Carnivores in Bulgaria

Parvoviruses represent the most important infectious agents that are responsible for severe to fatal disease in carnivores. This study reports the results of a 10‐year molecular survey conducted on carnivores in Bulgaria (n = 344), including 262 dogs and 19 cats with gastroenteritis, and 57 hunted wild carnivores. Real‐time polymerase chain reaction (qPCR), followed by virus characterization by minor groove binder (MGB) probe assays, detected 216 parvovirus positive dogs with a predominance of canine parvovirus type 2a (CPV‐2a, 79.17%) over CPV‐2b (18.52%) and CPV‐2c (2.31%). Rottweilers and German shepherds were the most frequent breeds among CPV‐positive pedigree dogs (n = 96). Eighteen cats were found to shed parvoviruses in their faeces, with most strains being characterized as FPLV (n = 17), although a single specimen tested positive for CPV‐2a. Only two wild carnivores were parvovirus positive, a wolf (Canis lupus) and a red fox (Vulpes vulpes), both being infected by CPV‐2a strains.