Canine parvovirus: current perspective

The first evidence of Asian-like CPV-2b in Slovakia in a vaccinated dog with an acute fatal course of parvovirus infection: a case report

This study provides a comprehensive description of the clinical course of a fatal parvovirus infection in a vaccinated dachshund puppy, along with the first identification of a new CPV-2 variant in Slovakia, elucidated through molecular amino acid analysis of the VP2 gene. The dog exhibited clinical signs such as apathy, vomiting, and bloody diarrhea. After confirming CPV-2 infection with a commercial snap test, intensive therapy was initiated. The dog succumbed within 48 h of admission. A rectal swab sample was collected, CPV-2 was examined using the PCR method, and sequenced. The virus detected in the patient was related to strains of CPV-2c of Asian origin and unrelated to European CPV-2b strains. The sequence had genetic signatures typical of Asian strains (VP2: 5Gly, 267Tyr, 324Ile, 370Arg, and 440Thr). Phylogenetic analysis classified this strain as similar to Asian strains of CPV-2c. It is believed to be derived from an Asian strain similar to CPV-2c that acquired the 426Asp mutation. With this finding, we present the first evidence of an Asian-like CPV-2b strain in the territory of Slovakia.

Epidemiology, molecular prevalence and prevention on canine parvovirus in India: A review

Canine parvovirus (CPV) is a highly contagious and lethal virus that causes severe gastroenteritis and myocarditis in young dogs. In 1978, CPV has rapidly spread worldwide, resulting in outbreaks and high morbidity rates among dog populations. Over a decade, CPV has undergone genetic changes, leading to the emergence of different genotypes (CPV-2a, CPV-2b, and CPV-2c), which have expanded its host range to include cats and tissue culture cells. This review focuses on CPV-2 outbreaks in India from 2010 to 2023, analyzing gene lengths covering 274-438 amino acids in the VP2 gene which are collected from the NCBI database to investigate CPV epidemiology and diversity. The study highlighted substantial differences in seroprevalence over the period for CPV-2 (7%), CPV-2a (45%), CPV-2b (12%), and CPV-2c (36%). Our study found significant seroprevalence differences among CPV variants, with CPV-2a being the most prevalent, underscoring the need for effective diagnostic and preventive strategies.

Chaperonin TRiC/CCT subunit CCT7 is involved in the replication of canine parvovirus in F81 cells

Canine parvovirus (CPV) is one of the most common lethal viruses in canines. The virus disease is prevalent throughout the year, with high morbidity and mortality rate, causing serious harm to dogs and the dog industry. Previously, yeast two hybrid method was used to screen the protein chaperonin containing TCP-1 (CCT7) that interacts with VP2. However, the mechanism of interactions between CCT7 and VP2 on CPV replication remains unclear. In this study, we first verified the interaction between CCT7 and viral VP2 proteins using yeast one-to-one experiment and co-immunoprecipitation (CoIP) experiment. Laser confocal microscopy observation showed that CCT7 and VP2 were able to co-localize and were mostly localized in the cytoplasm. In addition, the study of VP2 truncated mutant found that the interaction region of VP2 with CCT7 was located between amino acids 231 and 320. Cycloheximide (CHX) chase experiments showed that CCT7 can improve the stability of VP2 protein. After further regulation of CCT7 expression in F81 cells, it was found that the expression level of VP2 protein was significantly reduced after knocking down CCT7 expression by RNA interference (RNAi) or HSF1A inhibitor, and increased after overexpressing host CCT7. The study reveals the role of VP2 interacting protein CCT7 in the replication process of CPV, which could provide a potential target for the prevention and control of CPV.

A novel lateral flow immunochromatographic assay using a recombinant VP2 antigen for total antibody detection of canine parvovirus-2

Canine parvovirus-2 (CPV-2) is a viral disease of dogs causing acute hemorrhagic gastroenteritis and myocarditis with high morbidity and mortality rates. The infection is still widespread all over the world. Vaccines developed against infection have great importance in preventing infection. However, it is difficult to recommend a practical vaccination program without knowing the antibody level of a puppy. Despite widespread vaccination, difficulties in detecting the maternal antibodies in puppies remain the main cause of vaccination failure. The hemagglutination inhibition (HAI) test is the gold standard to determine the immune status of dogs for canine parvovirus 2, but the HAI test has several disadvantages such as the need for fresh porcine blood, well-equipped laboratory, and long incubation periods. In this study, for the first time we developed a colloidal gold-based competitive lateral flow assay (cLFA) system for the rapid detection of total antibodies in canine serum using CPV-2b-VP2 derived from field isolates. The recombinantly expressed capsid protein of CPV-2 in the prokaryotic expression system was used as a labeled molecule in cLFA. We carried out studies on our cLFA system using the standard antibody solution and the clinical samples from vaccinated puppy serum. We compared the results of the LFAs with the HAI test. Competitive lateral flow assay results showed good correlation with the gold standard method, the HAI test. In the developed platform, the limit of detection of the standard antibody was determined to be 375 ng mL-1, while the cut-off level of antibodies was observed to be 1 : 40 HAI titer in clinical samples. Our reported system will be a strong alternative for CPV-2 antibody-based detection applications.

Immunoinformatics for Novel Multi-Epitope Vaccine Development in Canine Parvovirus Infections

Canine parvovirus (CPV-2) is one of the most important pathogens of dogs of all ages, causing pandemic infections that are characterized by fatal hemorrhagic enteritis. The CPV-2 vaccine is recommended as a core vaccine for pet animals. Despite the intensive practice of active immunization, CPV-2 remains a global threat. In this study, a multi-epitope vaccine against CPV-2 was designed, targeting the highly conserved capsid protein (VP2) via in silico approaches. Several immunoinformatics methods, such as epitope screening, molecular docking, and simulation were used to design a potential vaccine construct. The partial protein sequences of the VP2 gene of CPV-2 and protein sequences retrieved from the NCBI were screened to predict highly antigenic proteins through antigenicity, trans-membrane-topology screening, an allergenicity assessment, and a toxicity analysis. Homologous VP2 protein sequences typically linked to the disease were identified using NCBI BLAST, in which four conserved regions were preferred. Overall, 10 epitopes, DPIGGKTGI, KEFDTDLKP, GTDPDDVQ, GGTNFGYIG, GTFYFDCKP, NRALGLPP, SGTPTN, LGLPPFLNSL, IGGKTG, and VPPVYPN, were selected from the conserved regions to design the vaccine construct. The molecular docking demonstrated the higher binding affinity of these epitopes with dog leukocyte antigen (DLA) molecules. The selected epitopes were linked with Salmonella enterica flagellin FliC adjuvants, along with the PADRE sequence, by GGS linkers to construct a vaccine candidate with 272 nucleotides. The codon adaptation and in silico cloning showed that the generated vaccine can be expressed by the E. coli strain, K12, and the sequence of the vaccine construct showed no similarities with dog protein. Our results suggest that the vaccine construct might be useful in preventing canine parvoviral enteritis (CPE) in dogs. Further in vitro and in vivo experiments are needed for the validation of the vaccine candidate.

Recovery of complete genomes of canine parvovirus from clinical samples

Canine parvovirus (CPV) is a highly pathogenic virus that affects dogs, especially puppies. CPV is believed to have evolved from feline panleukopenia virus (FPV), eventually giving rise to three antigenic types, CPV-2a, 2b, and 2c. CPV-2 is recognized for its resilience in contaminated environments, ease of transmission among dogs, and pathogenicity for puppies. Despite the relevance of the virus, complete genome sequences of CPV available at GenBank, to date, are scarce. In the current study, we have developed a methodology to allow the recovery of complete CPV-2 genomes directly from clinical samples. For this, seven fecal samples from Gurupi, Tocantins, North Brazil, were collected from puppies with clinical signals of viral enteritis, and submitted to viral DNA isolation and amplification. Two multiplex PCR strategies were designed including primers targeting fragments of 400 base pairs (bp) and 1,000 bp along the complete genome. Sequencing was performed with the Nanopore® technology and results obtained with the two approaches were compared. Genome assembly revealed that the 400 bp amplicons generated larger numbers of reads, allowing a more reliable coverage of the whole genome than those attained with primers targeting the larger (1000 bp) amplicons. Nevertheless, both enrichment methodologies were efficient in amplification and sequencing. Viral genome sequences were of high quality and allowed more precise typing and subtyping of viral genomes compared to the commonly employed strategy relying solely on the analysis of the VP2 region, which is limited in scope. The CPV-2 genomes recovered in this study belong to the CPV2a and CPV-2c subtypes, closely related to isolates from the neighboring Amazonian region. In conclusion, the technique reported here may contribute to increase the number of full CPV genomes available, which is essential for understanding the genetic mechanisms underlying the evolution and spread of CPV-2.

Whole genome sequence analysis of CPV-2 isolates from 1998 to 2020

Canine parvovirus-2 (CPV-2) is a virus with worldwide spread causing canine gastroenteritis. New strains of this virus have unique characteristics and are resistant to some vaccine strains. Therefore, understanding the root causes of resistance has proven to be of increasing concern to many scientists. This study collected 126 whole genome sequences of CPV-2 subtypes with specific collection dates from the NCBI data bank. The whole genome sequences of CPV-2 collected from different countries were analyzed to detect the new substitutions and update these mutations. The result indicated 12, 7, and 10 mutations in NS1, VP1, and VP2, in that respective order. Moreover, the A5G and Q370R mutations of VP2 are the most common changes in the recent isolates of the CPV-2C subtype, and the new N93K residue of VP2 is speculated to be the cause of vaccine failure. To summarize, the observed mutations, which are increasing over time, causes several changes in viral characteristic. A comprehensive understanding of these mutations can lead us to control potential future epidemics associated with this virus more efficiently.

Colloidal gold and fluorescent immunochromatographic test strips for canine parvovirus detection

Canine parvovirus (CPV) is an acute and highly infectious virus causing disease in puppies and, thus, affecting the global dog industry. The current CPV detection methods are limited by their sensitivity and specificity. Hence, the current study sought to develop a rapid, sensitive, simple, and accurate immunochromatographic (ICS) test to detect and control the spread and prevalence of CPV infection. More specifically, 6A8, a monoclonal antibody (mAb) with high specificity and sensitivity, was obtained by preliminary screening. The 6A8 antibody was labelled with colloidal gold particles. Subsequently, 6A8 and goat anti-mouse antibodies were coated onto a nitrocellulose membrane (NC) as the test and control lines, respectively. Furthermore, 6A8 and rabbit IgG antibodies were labelled with fluorescent microspheres and evenly sprayed onto a glass fibre membrane. Both strips could be prepared in 15 min with no noticeable cross-reactivity with other common canine intestinal pathogens. The strips were simultaneously used to detect CPV in 60 clinical samples using real-time quantitative PCR, hemagglutination, and hemagglutination inhibition assays. The colloidal gold (fluorescent) ICS test strip was stable for 6 (7) and 4 (5) months at 4 °C and room temperature (18-25 °C). Both test strips were easy to prepare and rapidly detected CPV with high sensitivity and specificity. Moreover, the results were easily interpretable. This study establishes a simple method for two CPV diseases, colloidal gold and fluorescent immunochromatographic (ICS) test strips. KEY POINTS: • CPV test strips do not exhibit cross-reactivity with other canine intestinal pathogens. • The strips are stable for months at 4 °C and at room temperature (18-25 °C). • These strips are a promising approach for the timely diagnosis and treatment of CPV.

Occurrence of canine parvovirus type 2c in diarrhoeic faeces of dogs in Kolkata, India

Canine parvovirus-2(CPV-2) causes a highly contagious disease of dogs characterised by acute hemorrhagic gastroenteritis, lethargy, vomiting, fever and usually bloody or mucoid diarrhoea. In the present study, 41 faecal samples collected from dogs exhibiting the signs of fever, vomition, bloody or mucoid diarrhoea in Kolkata, India were screened by haemagglutination test and PCR for detection of capsid protein coding VP2 gene. The viral genotype was detected by multiplex PCR and analysis of partial VP2 gene nucleotide sequences of selected PCR products with bioinformatics tool. Thirteen (31.71%) samples were found positive with HA titre ≥ 32 whereas 28 (68.29%) samples were positive by PCR of VP2 gene indicating higher sensitivity of PCR. Highest occurrence of CPV-2 was observed in the age group of 1-6 months (80.65%) and non-descript breeds with no history of vaccination (85%). Three samples were antigenic type CPV-2a, rest were CPV-2b/CPV 2c. Six CPV sequences were found to be highly similar to published CPV 2c sequences in BLAST analysis revealing a maximum identity of 99-100% with other CPV-2c strains and clustered together with CPV-2c strains of India and other countries in phylogenetic analysis. The present study highlights the need for continuous monitoring of samples to detect gradual changes in circulating CPV-2 genotypes in India.

Canine Parvovirus in Turkey: First Whole-Genome Sequences, Strain Distribution, and Prevalence

Canine parvovirus (CPV) is a significant pathogenic virus with up to 100% morbidity and 91% mortality rates, especially in unvaccinated puppies. The emergence of new strains, interspecies transmission, and vaccine effectiveness can be enabled by just a few base changes in the CPV genome. Therefore, to cope with CPV disease, it is important to identify the viral agent and regularly monitor vaccine effectiveness against new strains. The present study has investigated CPV's genetic profile in Turkey by collecting 80 samples from dogs in Turkey between 2020 and 2022. These samples and all sequences previously studied for CPV in Turkey were analyzed for whole-genome sequences, nationwide strain distribution over the two years, and the central Turkey prevalence rate. Next-generation sequencing was used for the genome study, Sanger sequencing for strain detection, and PCR for the prevalence analyses. The CPV-2 variants circulating in Turkey form their own cluster while being closely related to Egypt variants. Substantial amino acid changes were detected in antigenically important regions of the VP2 gene. Moreover, CPV-2b has become the most frequent genotype in this region, while the incidence of CPV-2c is predicted to increase gradually over the coming years. The prevalence of CPV in central Turkey was 86.27%. This study thus provides powerful insights to further our understanding of CPV's genetic profile in Turkey and suggests that up-to-date vaccination efficacy studies are urgently needed.

A comprehensive molecular survey of viral pathogens associated with canine gastroenteritis

Viral pathogens are the primary cause of canine gastroenteritis. However, few structured comprehensive studies on the viral etiology of canine gastroenteritis have been conducted. In this study, 475 rectal swabs collected over three years (2018-2021) from clinical canine gastroenteritis cases were screened for the presence of six major enteric viruses - canine parvovirus 2 (CPV-2), canine distemper virus (CDV), canine adenovirus 2 (CAdV-2), canine coronavirus (CCoV), canine astrovirus (CaAstV), and canine rotavirus (CRV) - by real-time PCR. The most frequently detected virus was CPV-2, which was present in 64.8% of the samples (subtype 2a, 21.1%; 2b, 77.4%; 2c, 1.5%), followed by CDV (8%), CaAstV (7.2%), CCoV (5.9%), and CAdV-2 (4.6%). Two to four of these viruses in different combinations were found in 16.8% of the samples, and CRV was not detected. The complete genome sequences of Indian isolates of CDV, CCoV, and CaAstV were determined for the first time, and phylogenetic analysis was performed. This study highlights the need for routine prophylactic vaccination with the appropriate vaccines. Notably, 70.3% of animals vaccinated with DHPPiL were found to be positive for at least one virus. Hence, regular molecular analysis of the prevalent viruses is crucial for addressing vaccination failures.

Experimental study of tropism of cultivated canine parvovirus in the immunogenesis organs of puppies

The immune system unites the organs and the tissues that protect the organism against genetically alien cells or substances entering the organism from the environment. Canine parvovirus is an etiologic agent of hemorrhagic gastroenteritis and causes a significant problem for veterinary medicine due to high level of morbidity and mortality, mostly among dogs, because of fast progression without immune-complement response. In this study, based on the results of our clinical, virological, histological, histochemical and morphological assays, we determined the pathogenetic role of parvovirus in sick dogs experimentally infected per os, specifically with isolated canine parvovirus (Antaeus) with titer of infectious activity equaling 3.80 ± 0.008 lg TCID50/cm, cultivated on heterological cell cultures. This allowed us to clarify, add to and generalize the data on the pathogenesis of the disease and determine pathohistological and histochemical changes in the immunogenesis, since the studied virus expresses immune-suppressive properties, leading to ruination of the locomotor ability of the organism and fast lethal outcome. The study of pathomorphological changes was carried out using pathoanatomical and histologic methods. Pathoanatomical material from the autopsy of puppies aged 45 days was fixed in 10% aqueous solution of neutral formaline and embedded in paraffin. Having parvoviral infection, dogs experience pathomorphologic changes in immune-complement organs, indicating inhibition of the immunogenesis function during an infectious disease of viral etiology. In the immunogenesis organs of puppies with the experimental reconstruction of parvoviral enteritis, we microscopically determined the following: edema of the cortex and medulla, disorganization of thymic corpuscules, and impairment of processes of differentiation of lymphocytes in the cortex and medulla of the thymic lobules; edema and large areas of accumulation of hemosiderin in the spleen as a result of breakdown of large amount of erythrocytes; acute inflammatory hyperemia of the parenchyma, swelling of sinuses, serous and serous-hemorrhagic lymphadenitis in lymph nodes. The complex of histologic changes in the immune protection organs, which we found in the conditions of experimental reconstruction of parvoviral infection, can be considered a distinct criterion for pathomorphologic differentiation diagnostics of parvoviral enteritis in dogs.

Predominance and first complete genomic characterization of canine parvovirus 2b in Turkey

Viral enteritis is a significant threat to domestic dogs. The two primary pathogens that cause viral enteritis in dogs are canine coronavirus (CCoV) and canine parvovirus (CPV). In this study, we investigated the occurrence of CPV-2, CCoV, and canine circovirus coinfection by characterizing circulating subtypes of CPV-2 in faecal samples from symptomatic dogs admitted to veterinary clinics located in Ankara, Elazığ, Kayseri, and Kocaeli provinces of Turkey, between 2019 and 2022. Virus detection by PCR and RT-PCR revealed that CPV-2 was present in 48 (77.4%) samples, and no other agents were detected. Based on the occurrence of the codon GAT at positions 1276 to 1278 (coding for aspartate at residue 426) of VP2, all CPV-2 isolates were confirmed to be of the CPV-2b subtype. The complete genome sequences of two CPV-2b isolates showed a high degree of similarity to and phylogenetic clustering with Australian and East Asian strains/isolates. The predominant CPV strain circulating in the three different regions of Turkey was found to be a CPV-2b strain containing the amino acid substitutions at Y324I and T440A, which commonly contribute to immune escape. This is the first report of complete genomic analysis of CPV-2 isolates circulating in symptomatic domestic dogs in Turkey. The evolution of CPV-2 has raised questions about the efficacy of current vaccination regimes and highlights the importance of monitoring the emergence and spread of new CPV-2 variants.

Canine parvovirus-2: An Emerging Threat to Young Pets

Canine parvovirus-2 (CPV-2) is a highly contagious and key enteropathogen affecting the canine population around the globe by causing canine parvoviral enteritis (CPVE) and vomition. CPVE is one of the the leading causes of morbidity and mortality in puppies and young dogs. Over the years, five distinct antigenic variants of CPV-2, namely CPV-2a, CPV-2b, new CPV-2a, new CPV-2b, and CPV-2c, have emerged throughout the world. CPV-2 infects a diverse range of wild animals, and the newer variants of CPV-2 have expanded their host range to include felines. Despite the availability of highly specific diagnostics and efficacious vaccines, CPV-2 outbreaks have been reported globally due to the emergence of newer antigenic variants, expansion of the viral host range, and vaccination failures. The present chapter describes the latest information pertaining to virus properties and replication, disease manifestations in animals, and an additional recent updates on diagnostic, prevention and control strategies of CPV-2.

Molecular Investigation of Recent Canine Parvovirus-2 (CPV-2) in Italy Revealed Distinct Clustering

Canine parvovirus Type 2 (CPV-2) is a worldwide distributed virus considered the major cause of viral gastroenteritis in dogs. Studies on Italian CPV-2 are restricted to viruses circulating until 2017. Only one study provided more updated information on CPV-2 but was limited to the Sicily region. No information regarding the circulation and genetic characteristics of CPV-2 in Northeast Italy has been made available since 2015. The present study investigated the genetic characteristics of CPV-2 circulating in the dog population of Northeast Italy between 2013 and 2019. The VP2 gene of 67 CPV-2 was sequenced, and phylogenetic analysis was performed to identify patterns of distribution. Phylogenetic and molecular analysis highlighted unique characteristics of Northeast Italian CPV-2 and interestingly depicted typical genetic clustering of the Italian CPV-2 strains, showing the existence of distinct CPV-2 genetic groups. Such analysis provided insights into the origin of some Italian CPV-2 genetic clusters, revealing potential introductions from East European countries and the spread of CPV-2 from South/Central to North Italy. This is the first report that describes the genetic characteristics of recent Italian CPV-2. Tracking the genetic characteristics of CPV-2 nationally and globally may have impact on understanding the evolution and distribution of CPV-2, in particular in light of the current humanitarian emergency involving Ukraine, with the massive and uncontrolled movement of people and pet animals.

First report of canine bufavirus in India

Canine bufavirus (CBuV), a novel protoparvovirus of dogs that is associated with enteric and respiratory symptoms, has been reported only in Italy and China. The enteric prevalence of CBuV in India was investigated, and the nearly complete genome sequence (4292 bp) was amplified and reconstructed for one strain. A nucleotide sequence alignment indicated 93.42–98.81% identity to the other available CBuV sequences and 70.88–73.39% and 54.4–54.8% identity to human bufavirus and canine parvovirus 2 (CPV-2), respectively. The current strain is most closely related to Chinese CBuV strains, which together form an Asian lineage. This first report of the prevalence of CBuV in India emphasizes the need for further epidemiological surveillance.

Canine parvovirology - A brief updated review on structural biology, occurrence, pathogenesis, clinical diagnosis, treatment and prevention

Canine parvovirus (CPV) is a major cause of hemorrhagic diarrhea and mortality in puppies worldwide. There are 2 types of Parvovirus which affects canines: Canine parvovirus 2 (CPV-2) and Canine parvovirus 1 (CPV-1) or the Minute Virus of Canine (MVC). CPV-2 originated from Feline panleukopenia virus and has undergone genetic variation to give rise to its three variants (CPV-2a, CPV-2b and CPV-2c). Amino acid substitutions in VP2 capsid protein have led virus to adapt new host range. The original CPV-2 was known to be dominant in Japan, Belgium, Australia as well as USA and later circulated throughout the world. Clinically, CPV-2 infection is characterized by anorexia, lethargy, depression, vomiting, leukopenia and severe hemorrhagic diarrhea. Several diagnostic tests have been developed to detect parvoviral infections which are categorized into immunological tests (latex agglutination test, SIT-SAT and ELISA etc.) and molecular based tests (PCR, mPCR and RT-PCR etc.). To control and manage the disease several treatments like fluid therapies, antibiotics, and adjunctive treatments are available and some are in various stages of development. Apart from this, many vaccines are also commercially available and some are in developmental stages. The present review contains detailed information regarding structural biology, occurrence, pathogenesis, clinical diagnosis, treatments and prevention in order to understand the need and the growing importance of CPV-2.

Effect of sampling site on the diagnosis of canine parvovirus infection in dogs using polymerase chain reaction

Background

Accurate diagnosis is imperative in dogs with clinical signs of parvovirus infection (CPV‐2).

Objectives

To assess quantitative real‐time PCR (qRT‐PCR) for the diagnosis of CPV‐2 infection, and determine the optimal sampling site. Secondarily, to compare qRT‐PCR with a point‐of‐care PCR kit (PCRun), and to assess sensitivity of serology for CPV diagnosis.

Animals

Sixty dogs with naturally acquired parvovirus infection, 44 unvaccinated puppies, of which 16 were followed after first and second vaccination, 15 adult dogs, of which 10 were followed also after a booster vaccine, and 9 dogs with distemper virus infection.

Methods

Prospective study. Samples from the rectum, blood, and pharynx were obtained for PCR.

Results

All dogs with a clinical diagnosis of parvovirus infection were positive by qRT‐PCR in at least 1 sampling site (ie, rectum, blood, pharynx), and 50 (83%) of 60 were positive in all sites. qRT‐PCR was negative in 67 (99%) of 68 healthy puppies (before‐vaccination), puppies with distemper, and healthy adult dogs. Ten days after initial vaccination of puppies, 62% (fecal), 31% (blood), and 12% (pharyngeal) of samples were positive for CPV‐2 on qRT‐PCR. The proportion of positive pharyngeal samples decreased 20 days after vaccination and all sites were negative 12‐28 days after second vaccination. Vaccinated adults were negative before and after booster vaccination.

Conclusions and Clinical Importance

Molecular detection of CPV is sensitive, but specificity is hampered temporarily during the vaccination period. Blood, feces, and pharynx are suitable sampling sites. Fecal samples had the lowest sensitivity in sick dogs and highest positivity in puppies after vaccination.

Molecular diversity of the VP2 of Carnivore protoparvovirus 1 (CPV-2) of fecal samples from Bogotá

BACKGROUND

Carnivore protoparvovirus 1, also known as canine parvovirus type 2 (CPV-2), is the main pathogen in hemorrhagic gastroenteritis in dogs, with a high mortality rate. Three subtypes (a, b, c) have been described based on VP2 residue 426, where 2a, 2b, and 2c have asparagine, aspartic acid, and glutamic acid, respectively.

OBJECTIVES

This study examined the presence of CPV-2 variants in the fecal samples of dogs diagnosed with canine parvovirus in Bogotá.

METHODS

Fecal samples were collected from 54 puppies and young dogs (< 1 year) that tested positive for the CPV through rapid antigen test detection between 2014-2018. Molecular screening was developed for VP1 because primers 555 for VP2 do not amplify, it was necessary to design a primer set for VP2 amplification of 982 nt. All samples that were amplified were sequenced by Sanger. Phylogenetics and structural analysis was carried out, focusing on residue 426.

RESULTS

As a result 47 out of 54 samples tested positive for VP1 screening, and 34/47 samples tested positive for VP2 980 primers as subtype 2a (n = 30) or 2b (n = 4); subtype 2c was not detected. All VP2 sequences had the amino acid, T, at 440, and most Colombian sequences showed an S514A substitution, which in the structural modeling is located in an antigenic region, together with the 426 residue.

CONCLUSIONS

The 2c variant was not detected, and these findings suggest that Colombian strains of CPV-2 might be under an antigenic drift.

Increased survival in puppies affected by Canine Parvovirus type II using an immunomodulator as a therapeutic aid

Canine parvovirus type II (CPV-2) infection induces canine parvoviral enteritis (CPE), which in turn promotes sepsis and systemic inflammatory response syndrome (SIRS). Mortality in this disease is usually registered within 48-72 h post-hospitalization, the critical period of the illness. It has been recently described that the use of an immunomodulator, whose major component is monomeric ubiquitin (mUb) without the last two glycine residues (Ub∆GG), in pediatric human patients with sepsis augments survival. It is known that CXCR4 is the cell receptor of extracellular ubiquitin in humans. This work aimed to explore the effect of one immunomodulator (human Dialyzable Leukocyte Extract-hDLE) as a therapeutic auxiliary in puppies with sepsis and SIRS induced by CPE. We studied two groups of puppies with CPV-2 infection confirmed by polymerase chain reaction. The first group received conventional treatment (CT) and vehicle (V), while the second group received CT plus the immunomodulator (I). We assessed both groups' survival, clinical condition, number of erythrocytes, neutrophils, and lymphocytes during the hospitalization period. In addition, hematocrit, hemoglobin, plasma proteins and cortisol values, as well as norepinephrine/epinephrine and serotonin concentration were determined. Puppies treated with CT + I showed 81% survival, mild clinical signs, and a significant decrease in circulating neutrophils and lymphocytes in the critical period of the treatment. In contrast, the CT + V group presented a survival of 42%, severe clinical status, and no improvement of the parameters evaluated in the critical period of the disease. We determined in silico that human Ub∆GG can bind to dog CXCR4. In conclusion, the administration of a human immunomodulator (0.5 mg/day × 5 days) to puppies with CPE under six months of age reduces the severity of clinical signs, increases survival, and modulates inflammatory cell parameters. Further studies are necessary to take full advantage of these clinical findings, which might be mediated by the human Ub∆GG to canine CXCR4 interaction.

Isolation and Genetic Characterization of Canine Parvovirus in a Malayan Tiger

Naïve Felidae in the wild may harbor infectious viruses of importance due to cross-species transmission between the domesticated animals or human–wildlife contact. However, limited information is available on virus shedding or viremia in the captive wild felids, especially in Malaysia. Four infectious viruses of cat, feline herpesvirus (FHV), feline calicivirus (FCV), canine distemper virus (CDV), and canine parvovirus (CPV), were screened in leopards, feral cats, and tigers in Malaysia based on virus isolation in Crandell-Rees feline kidney (CRFK) cells, PCR/RT-PCR, and whole-genome sequencing analysis of the positive isolate. From a total of 36 sera collected, 11 samples showed three consecutive cytopathic effects in the cell culture and were subjected to PCR using specific primers for FHV, FCV, CDV, and CPV. Only one sample from a Malayan tiger was detected positive for CPV. The entire viral genome of CPV (UPM-CPV15/P. tigris jacksoni; GenBank Accession number MW380384) was amplified using the Sanger sequencing approach. Genome sequencing of the isolate revealed 99.13, 98.65, and 98.40% close similarity to CPV-31, CPV-d Cornell #320, and CPV-15 strains, respectively, and classified as CPV-2a. Time-scaled Bayesian Maximum Clade Credibility tree for the non-structural (NS) genes of CPV showed a close relationship to the isolates CPV-CN SD6_2014 and KSU7-SD_2004 from China and USA, respectively, while the capsid gene showed the same ancestor as the FPV-BJ04 strain from China. The higher evolution rate of the capsid protein (CP) (VP 1 and VP2) [1.649 × 10⁻⁵ (95% HPD: 7.626 × 10⁻³ to 7.440 × 10⁻³)] as compared to the NS gene [1.203 × 10⁻⁴ (95% HPD: 6.663 × 10⁻³ to 6.593 × 10⁻³)] was observed in the CPV from this study, and fairly higher than other parvovirus species from the Protoparvovirus genus. Genome sequencing of the isolated CPV from a Malayan tiger in the present study provides valuable information about the genomic characteristics of captive wild felids, which may add information on the presence of CPV in species other than dogs.

A novel one-step amplification refractory mutation system PCR (ARMS-PCR) for differentiation of canine parvovirus-2 variants

Enteritis caused by CPV-2 antigenic variants (CPV-2a, 2b, and 2c) is frequently reported in dogs worldwide leading to significant morbidity and mortality. Here, we describe about a simple, single-step, ARMS-PCR strategy targeting the mutant 426 amino acid of VP2 to differentiate CPV-2 antigenic types. A total of 150 fecal samples were subjected to ARMS-PCR of which 18 were typed as CPV-2a, 79 were typed as CPV-2b, and 6 were typed as CPV-2c. The ARMS-PCR results were validated by randomly sequencing partial VP2 gene of 14 samples. Phylogenetic analysis of partial VP2 gene sequencing of each of the CPV-2 variants revealed that CPV-2a and CPV-2b isolates formed a separate clade of Indian lineage, while CPV-2c shared common evolutionary origin with Asian lineage. The developed technique is first of its kind, one-step, rapid, sequencing independent method for typing of CPV-2 antigenic variants.

Genetic diversity of canine parvovirus variants circulating in Nigeria

Canine parvovirus (CPV) is a fast-evolving single-stranded DNA virus that causes severe and fatal gastrointestinal disease in dogs. Lately, several mutations affecting viral protein (VP) capsid resulting in highly pathogenic variants with distinctive immunological and clinicopathological characteristics abound. This study involved screening stools of 44 randomly selected clinical cases of canine gastroenteritis from 4 cities (Ibadan, Jos, Makurdi, and Zaria) in Nigeria for CPV antigen using an on-the-spot immunoassay test kit, as well as, molecular detection of viral nucleic acid by polymerase chain reaction. Subsequently, nucleic acid sequencing of 1195-bp amplicons encompassing the VP2 encoding region was done. The resultant 40 high-quality amino acid sequences obtained were analysed for the identification and grouping of the viruses into their discrete variants - CPV-2a, CPV-2b, or CPV-2c, using key amino acids substitutions - Asn, Asp, or Glu respectively at position 426 of the VP2 gene. One-third (11/40; 27.5%) of the analysed sequences were identified as CPV-2a and two-third (29/40; 72.5%) as CPV-2c. The original CPV and CPV-2b were not detected. Also, the "new CPV-2a variant" with mutation S297A identified had two additional mutations (Y324I and T440A) associated with selective pressure and vaccination failure in their sequences. Similarly, unique CPV-2c mutants carrying genetic markers (S297A, Y324I, and Q370R) that are highly related to CPVs of Asian origin were observed. These findings revealed a high level of divergence of existing CPVs in circulation; suggesting that CPV is rapidly evolving in Nigeria lately.

Concepts to Reveal Parvovirus-Nucleus Interactions

Parvoviruses are small single-stranded (ss) DNA viruses, which replicate in the nucleoplasm and affect both the structure and function of the nucleus. The nuclear stage of the parvovirus life cycle starts at the nuclear entry of incoming capsids and culminates in the successful passage of progeny capsids out of the nucleus. In this review, we will present past, current, and future microscopy and biochemical techniques and demonstrate their potential in revealing the dynamics and molecular interactions in the intranuclear processes of parvovirus infection. In particular, a number of advanced techniques will be presented for the detection of infection-induced changes, such as DNA modification and damage, as well as protein-chromatin interactions.

Molecular characterization of canine parvovirus from domestic dogs in Nigeria: Introduction and spread of a CPV-2c mutant and replacement of older CPV-2a by the "new CPV-2a" strain

Canine parvovirus (CPV) is a contagious and highly pathogenic virus of dogs. After its first report in 1978, the CPV original type (CPV-2) was rapidly and totally replaced by three antigenic variants named CPV-2a, CPV-2b and CPV-2c that circulate in various countries at different frequencies and recently reported in Nigeria. This study describes the molecular characterization of 28 CPV strains in dogs presenting with gastroenteritis in veterinary clinics at Lagos and Ibadan, Nigeria. The results show the predominance (92.8%) of CPV-2a, while CPV-2c was found only in two samples. Phylogenetic analyses revealed that the CPV Nigerian strains were closely related to Asian strains and 26 CPV-2a out of 28 CPV sequences fell into 2 different subclades consistent with predicted amino acid mutations at position 267, 321, 324 and 440. Lys321Asn was evident in all the Nigerian strains whilst Phe267Tyr and Tyr324Ile were observed in 96.4% of the sequences, respectively. Thr440Ala occurred in 89.3% of sequences from this study. The new CPV-2a was predominant and appears to have replaced other CPV-2a strains in South-western Nigeria whilst the CPV-2c strain which is identical to the isolate recently reported in Northern Nigeria, may have been introduced in this country at the time of this study. Monitoring virus epidemiology is important to better understand the dynamics of CPV evolution and the eventual need to change or improve existing vaccination strategies.

Domestic Dogs and Wild Foxes Interactions in a Wildlife-Domestic Interface of North-Central Chile: Implications for Multi-Host Pathogen Transmission

Domestic dogs (Canis familiaris) often cohabite at interfaces shared by humans and wildlife, interacting with wild canids as predators, prey, competitors and reservoirs of several multi-host pathogens, such as canid-borne micro and macro parasites that could impact on wildlife, livestock and public health. However, spatio-temporal patterns of indirect interactions as promoters of pathogen transfer between domestic and wild canids are largely unknown. In this study, we used camera traps to describe the activity patterns and habitat use of dogs, chilla (Lycalopex griseus) and culpeo (Lycalopex culpaeus) foxes and identify the local-scale factors that may affect the frequency of dog-fox interactions through an anthropization gradient of the Coquimbo region, Chile. We assessed local-scale variables that may predict the number of interactions between dogs and foxes, and compared the time interval between dog-culpeo and dog-chilla interactions. Our findings suggested that closeness to urbanized zones predicts the frequency of indirect interactions between dogs and foxes. We found higher number of dog-fox interactions (60 interactions) at a periurban site adjacent to two coastal towns (Tongoy and Guanaqueros), compared to other two more undisturbed sites (12 interactions) increasingly distanced from urbanized areas. We showed that dogs interacted more frequently with chilla foxes (57 interactions) than with culpeo foxes (15 interactions), and the first interaction type occurred almost exclusively at the periurban site, where dogs and chillas were more frequently detected than in the other sites. We detected a marked temporal segregation between dogs and foxes, but dog-chilla interactions resulted in shorter time intervals (2.5 median days) compared to dog-culpeo interactions (7.6 median days), suggesting a higher potential risk of pathogen spillover between the first species pairing. Based on previous studies, we suggest periurban zones may constitute a potential focus of pathogen exposure between dog and fox populations in the study area. Our research contributes to improving the knowledge on the spatio-temporal patterns of interspecific contact between invasive and native carnivores within the context of multi-host pathogen dynamics. Our outcomes will inform theoretical epidemiological models designed to predict and minimize the contact risk between domestic and threatened species, guiding effective control strategies at the wildlife-domestic interface.

First detection of canine parvovirus 2b DNA in a crab-eating fox pup (Cerdocyon thous, Linnaeus, 1766)

The crab-eating fox (Cerdocyon thous) is a small wild mammal present in all Brazilian biomes and in some countries of South America. This study aimed to verify the involvement of viral infectious agents in the death of a wild crab-eating fox pup (Cerdocyon thous) in Brazil. The Center for Medicine and Research of Wild Animals of the Universidade Estadual Paulista received a free-living crab-eating fox aged approximately 21 days and apparently healthy. After 13 days, the animal presented anorexia, diarrhea, fever, prostration, and neurological signs progressing to death with an inconclusive diagnosis. In a retrospective study, tissue fragments stored at - 80 °C were used to identify nucleic acids from major canine viruses, such as canine parvovirus-2 (CPV-2), canine adenovirus A types 1 and 2, canid alphaherpesvirus 1, and canine distemper virus. The amplified product with the expected length for CPV-2 was obtained from the heart fragment. After performing nucleotide (nt) sequencing of the amplicon, it was possible to demonstrate that the crab-eating fox strain exhibited high (99.8%) nt identity with the CPV-2b prototype (CPV-39 strain). Additionally, deduced amino acid (aa) sequence analysis showed the GAT codon for the aa Asp (D) at position 426 of the CPV-2 viral protein VP2, which characterizes the subtype 2b. To the best of the authors' knowledge, this report describes the first detection of CPV-2b DNA in tissue fragments from a crab-eating fox.

Molecular characterisation of canine parvoviruses from clinical samples and vaccines in Nigeria

Canine parvovirus (CPV) the causative agent of canine parvovirus enteritis is an intractable pathogen of dogs characterised by mutations, evolutionary changes and eventual vaccine failure. The disease is a serious problem in dogs with limited studies conducted in Nigeria. Therefore, this study was designed to characterise the subtypes of CPV isolates in six commonly used vaccines and 157 clinical samples collected from seven states in Nigeria from June 2016 to March 2018. Faecal samples collected from the clinical cases were subjected to in-clinic immunoassay to detect viral antigens. Polymerase chain reaction (PCR) was used to amplify viral VP2 gene in the samples and commonly used vaccines in Nigeria. Thereafter, PCR products were sequenced and analysed. The result showed that 93.0% of the dogs tested positive for CPV in both assays; 72.8% were puppies less than six months old, with 58.3% of them vaccinated. Partial VP2 gene sequence and phylogenetic analysis of 11 random clinical samples showed that CPV-2c 7(63.6%) and CPV-2a 4(36.4%) were the predominant subtypes in Nigeria; with genetic signatures that are 98.7% to 99.9% closely related to Asian and European strains, respectively. No CPV-2b was detected. Amino acid mutation analysis divulged some imperative transmutation sites: D305Y, Y324I, Q370R, N375D, T440A, Y444S, I447M and Y451C in the isolates. The viruses in the vaccines were characterised as the wild-type CPV. The genetic variability, viral population heterogeneity and phylogenetic linkage with isolates from other countries probably suggest transboundary migrations and local differentiations are contributing to continuous CPV evolution and vaccine failure in Nigeria.

Assessment of certain biomarkers for predicting survival in response to treatment in dogs naturally infected with canine parvovirus

Canine parvovirus (CPV) enteritis is an important cause of morbidity and mortality in puppies despite aggressive treatment. Identification of reliable biomarkers for CPV enteritis is essential to determine the severity, duration of hospitalization, and predict the clinical outcome. Meanwhile, the biomarkers will assist in decision-making with clients about the further course of treatment or euthanasia. The present study was conducted to evaluate the changes of total leukocyte count (TLC), neutrophil count, and serum concentrations of creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), intestinal fatty acid binding protein-2 (IFABP-2), albumin, ceruloplasmin (Cp), cortisol, free triiodothyronine (FT₃) and free thyroxine (FT₄) in survivors and non-survivors as a predictor of the clinical outcome. Marked leukopenia, neutropenia, hypoalbuminemia, elevated levels of CK-MB, IFABP-2, Cp, and cortisol were noticed in CPV-infected dogs than healthy dogs but, LDH, FT₃ and FT₄ concentrations did not differ significantly. The CPV-infected non-survivors had persistent leukopenia, neutropenia and elevated CK-MB, IFABP-2, Cp and cortisol concentrations at 72 h of commencement of treatment. In CPV-infected survivors, TLC and neutrophil count were significantly increased, and CK-MB, IFABP-2, Cp and cortisol concentrations were significantly decreased at 72 h of commencement of treatment. The positive predictive values (PPVs) for survival using cut-off value of TLC (>3.2 × 10³/μL), neutrophil count (>1.65 × 10³/μL), CK-MB (≤234.50 U/L), IFABP-2 (≤7.61 ng/mL), Cp (≤0.605 g/L) and cortisol (≤16.90 ng/mL) were determined as 89.47%, 88.88%, 94.73%, 93.33%, 94.44% and 89.47%, respectively with better area under receiver operating characteristic (ROC) curve as well as sensitivity. The magnitude of decrease in TLC, neutrophil count, and increase in CK-MB, IFABP-2, Cp and cortisol concentrations at 72 h of initiation of treatment in dogs with parvoviral enteritis could be useful indicators for the prognosis of the disease. Based on sensitivity (%) and specificity (%) from ROC curve analysis and PPV (%), it is concluded that serum CK-MB concentration will serve as the most useful biomarker followed by Cp and absolute neutrophil count.

Pathological, Bacteriological and Virological Findings in Sudden and Unexpected Deaths in Young Dogs

Simple Summary

“Sudden death” has been defined by the World Health Organization as a non-violent, unexpected death occurring less than 24 h from the onset of symptoms. The causes of sudden death have been widely investigated in human forensic medicine. In contrast, few studies have been reported in the veterinary literature. This study aimed to investigate the frequency of sudden deaths in young dogs in different age ranges. A secondary aim was to collect information regarding clinical symptoms, and pathological and microbiological findings related to sudden death in young dogs. The results of the present study demonstrate that the highest frequency of sudden death occurs in animals in an age range from 10 days to 1 month and from 6 to 12 months. The most frequently observed clinical symptoms in cases of sudden death were acute respiratory symptoms. Furthermore, Canine parvovirus type 2, E. coli, Canine Distemper Virus, Clostridium perfringens type A, and Pasteurella spp. were the main causes of death observed in the present study. The results reported in the present study could provide a reference basis to better investigate sudden death in veterinary clinical practice.

Abstract

In human medicine, “sudden death” has been defined by the World Health Organization (WHO) as a non-violent, unexpected death occurring less than 24 h from the onset of symptoms. The aims of this study were: (1) to estimate the proportional mortality ratio for “sudden and unexpected death” (SUD) in young dogs; (2) to investigate the pathological and microbiological findings in SUD cases in young dogs. For these purposes, a retrospective study of a total of 145 cases of young dead dogs was performed. For each case, we collected information about the age, medical history and the gross and microbiological findings of the animals. The results of this study found 21 cases of SUD. The most frequently observed clinical symptoms in the cases of sudden death were acute respiratory symptoms, followed by acute gastroenteric symptoms, non-specific symptoms and neurological symptoms. The evaluation of necropsy reports allowed us to observe enteritis in 18 out of 21 cases and pneumonia in seven out of 21 cases. Viral infection with Canine parvovirus type 2 was the most common cause of SUD observed. These results could provide a valuable tool for the investigation of sudden death in young dogs.

Canine parvovirus prevention-What influence do socioeconomics, remoteness, caseload and demographics have on veterinarians' perceptions and behaviors?

Canine parvovirus (CPV) is a cause of severe disease in dogs globally, yet is preventable by vaccination. A range of vaccination protocols are used by veterinary practitioners with evidence suggesting some protocols provide better protection than others in high infection-risk situations. This study investigated associations between veterinarians' vaccination recommendations and hospital remoteness, socioeconomic disadvantage, CPV caseload, and veterinarian perceptions and demographics. A national Australian veterinary survey in 2017 received 569 practitioner responses from 534 unique hospitals (23.6 % response rate). Respondents from major city hospitals had the lowest perceptions of the national CPV caseload (p < 0.0001). Those from hospitals with mild to moderate caseloads (6-40 cases per annum) recommended more frequent puppy revaccination - which is considered more protective - than those with the highest caseload (p = 0.0098), which might increase vaccination failure risk. Respondents from the most socioeconomically disadvantaged regions were over-represented in recommending annual revaccination of adult dogs; those from the least disadvantaged regions were over-represented in recommending triennial revaccination (p < 0.0001). Hospitals with higher CPV caseloads, greater socioeconomic disadvantage or increased remoteness did not favor two puppy vaccination protocols that are considered more protective (younger first vaccination age or older final vaccination age), despite these regions presenting higher CPV caseload risk. Titer testing to determine whether to revaccinate was more likely to be used in major city hospitals (p = 0.0052) and less disadvantaged areas (p = 0.0550). University of graduation was associated with CPV caseload, remoteness and level of socioeconomic disadvantage of the region where the graduate worked. University of graduation was significantly associated with age for final puppy vaccination and titer-testing recommendations. Graduates from one university were over-represented in recommending an earlier (10-week) finish protocol and titer testing, compared to all other universities. Year and university of graduation, and respondent's age were associated with a number of vaccination protocol recommendations suggesting that inherent biases might affect veterinarians' decisions. Emphasis on currently recommended vaccination protocols in undergraduate curricula and more protective vaccination protocol use in higher-risk regions could reduce immunization failure and CPV caseload.

Lifestyle as Risk Factor for Infectious Causes of Death in Young Dogs: A Retrospective Study in Southern Italy (2015-2017)

Infectious diseases are a common cause of death in young dogs. Several factors are thought to predispose young dogs to microbiological infections. Identifying the cause of death is often a challenge, and broad diagnostic analysis is often needed. Here, we aimed to determine the infectious causes of death in young dogs aged up to 1 year, examining how it relates to age (under and over 6 months), lifestyle (owned versus ownerless), breed (purebred and crossbreed), and gender. A retrospective study was conducted in a 3-year period (2015-2017) on 138 dead dogs that had undergone necropsy and microbiological diagnostics. Enteritis and pneumonia were the most commonly observed lesions. Polymicrobism was more prevalent (62.3%) than single-agent infections and associated with a higher rate of generalised lesions. Ownerless dogs showed over a three-fold higher predisposition to viral coinfections than owned dogs. Above all, canine parvovirus was the most prevalent agent (77.5%), followed by canine coronavirus (31.1%) and canine adenovirus (23.9%); ownerless pups had a higher predisposition to these viruses. Escherichia coli (23.9%), Clostridium perfringens type A (18.1%), and Enterococcus spp. (8.7%) were the most commonly identified bacteria, which mostly involved in coinfections. A lower prevalence of CDV and Clostridium perfringens type A was observed in puppies under 6 months of age. In conclusion, this study is the first comprehensive survey on a wide panel of microbiological agents related to necropsy lesions. It lays the groundwork for future studies attempting to understand the circulation of infectious agents in a determined area.

A Decade of Treatment of Canine Parvovirus in an Animal Shelter: A Retrospective Study

Here, we present 11.5 years of monthly treatment statistics showing an overall intake of 5127 infected dogs between June 2008 and December 2019, as well as more detailed datasets from more recent, less protracted time periods for the examination of mortality risk, seasonality, and resource requirements in the mass treatment of canine parvovirus (CPV) in a private animal shelter. The total survival rate of animals during the study period was 86.6% (n = 4438/5127 dogs survived) with the probability of survival increasing to 96.7% after five days of treatment (with 80% of fatalities occurring in that period). A distinct parvovirus season peaking in May and June and troughing in August, September, December, and January was observed, which could have contributed as much as 41 animals peak-to-trough in the monthly population (with a potential, smaller season occurring in October). Low-weight and male animals were at higher risk for death, whereas age was not a significant contributing factor. Treatment time averaged 9.03 h of total care during a seven-day median treatment duration. These findings, taken together, demonstrate that canine parvovirus can be successfully treated in a sustainable manner within a shelter setting using a largely volunteer workforce.

Risk, prognosis and causality of parvo viral enteritis in dogs in Sri Lanka

We studied the causal variation, prognosis and risk factors of parvo viral enteritis using both molecular and statistical analysis. A multivariate factor analysis was performed to see the effect of the breed, age, vaccination status and the leukocyte counts on disease severity and survival. Twenty PCR amplicons (partial VP2 gene) from vaccinated dogs were sequenced to identify the variants. A total of 109 samples were positive for parvo viral DNA, 71 of which were from dogs who have received at least one dose of CPV-2 vaccine. Over 90% were leukopenic on 2^nd and 3^rd day of diarrhoea. Age < 6 months was negatively correlated with leukocyte count and the leukocyte count was negatively correlated with survival. Dobermans and Labradors showed significant negative correlation with survival. All variants of parvovirus affected dogs with the 2c being the predominant (2c = 12, 2a = 7, 2b = 1). All 20 strains harboured three additional amino acid substitutions (i.e. Phe267Tyr, Ser297Ala and Tyr324Ile) and warrant further studies on potential changes of the antigenicity of the virus.

Canine parvovirus 2b in fecal samples of asymptomatic free-living South American coatis (Nasua nasua, Linnaeus, 1766)

Canine parvovirus type 2 (CPV-2) is classified into three subtypes (CPV-2a, CPV-2b, and CPV-2c) and is the main cause of enteritis and myocarditis in young domestic and wild animals. This study aimed to evaluate the presence of CPV-2 in the feces of asymptomatic free-living coatis from Garden Forest Reserve, Palmital city, SP, Brazil. Fecal samples from 21 coatis (both sexes, different ages, and different aspects of feces) were collected in August 2014 and March 2015. The nucleic acid extracted was submitted to a polymerase chain reaction (PCR) assay to amplify a fragment of the VP2 gene of CPV-2. Eight (38%) fecal samples were positive in the PCR assay and were confirmed by sequencing. The 7 nucleotide (nt) sequences analyzed showed 100% nt identity with the prototype strain of CPV-2b (CPV-39 strain). The analysis of the deduced amino acid (aa) sequence revealed the presence of the GAT codon (aa D-Asp) at position 426 of the VP2 viral protein (subtype 2b). This study describes for the first time the identification of CPV-2b in asymptomatic free-living coatis (Nasua nasua) and suggests that coatis are susceptible to Carnivore protoparvovirus 1 infection and are important as a reservoir and an asymptomatic carrier to other wild and domestic animal species.

Murine and related chapparvoviruses are nephro-tropic and produce novel accessory proteins in infected kidneys

Mouse kidney parvovirus (MKPV) is a member of the provisional genus Chapparvovirus that causes renal disease in immune-compromised mice, with a disease course reminiscent of polyomavirus-associated nephropathy in immune-suppressed kidney transplant patients. Here we map four major MKPV transcripts, created by alternative splicing, to a common initiator region, and use mass spectrometry to identify “p10” and “p15” as novel chapparvovirus accessory proteins produced in MKPV-infected kidneys. p15 and the splicing-dependent putative accessory protein NS2 are conserved in all near-complete amniote chapparvovirus genomes currently available (from mammals, birds and a reptile). In contrast, p10 may be encoded only by viruses with >60% amino acid identity to MKPV. We show that MKPV is kidney-tropic and that the bat chapparvovirus DrPV-1 and a non-human primate chapparvovirus, CKPV, are also found in the kidneys of their hosts. We propose, therefore, that many mammal chapparvoviruses are likely to be nephrotropic.

Parvoviruses are small, genetically simple single-strand DNA viruses that remain viable outside their hosts for very long periods of time. They cause disease in several domesticated species and in humans. Mouse kidney parvovirus (MKPV) is a causative agent of kidney failure in immune-compromised mice and is the only member of the provisional Chapparvovirus genus for which the complete genome including telomeres is known. Here, we show that MKPV propagates almost exclusively in the kidneys of mice infected naturally, wherein it produces novel accessory proteins whose coding regions are conserved in amniote-associated chapparvovirus sequences. We assemble a closely related complete viral genome present in DNA extracted from the kidney of a wild Cebus imitator monkey, and show that another related chapparvovirus is preferentially found in kidneys of the vampire bat Desmodus rotundus. We conclude that many mammal-hosted chapparvovirus are adapted to the kidney niche and may therefore cause disease following kidney stress in multiple species.

Detection of canine parvovirus types 2b and 2c in canine faecal samples contaminating urban thoroughfares in Brazil

Canine parvovirus type 2 (CPV-2) is a highly contagious virus that causes acute gastroenteritis in dogs all over the world. Because of its stability in the environment, CPV-2 can remain infective for a long time, especially if protected in organic matter. To demonstrate CPV-2's potential as an environmental hazard for nonimmunized susceptible hosts, we investigated 50 faecal samples collected from public areas in a municipality of Paraná state, Brazil. Seven samples tested positive for CPV by a PCR assay targeting the partial VP2 gene, with three strains being confirmed as CPV-2b variant and one as CPV-2c variant by sequence analysis. These findings were supported by phylogenetic analysis, and the species identity of faecal samples source was confirmed by canine mitochondrial DNA amplification and sequencing. Our results demonstrate the presence of CPV in canine faeces contaminating urban thoroughfares and reinforce the importance of environmental control to reduce the potential exposure risks to susceptible hosts.

Development of Dog Immune System: From in Uterus to Elderly

Immune system recognize and fight back foreign microorganisms and inner modifications that lead to deficient cell and tissue functions. During a dog's life, the immune system needs to adapt to different physiological conditions, assuring surveillance and protection in a careful and controlled way. Pregnancy alters normal homeostasis, requiring a balance between immunity and tolerance. The embryos and fetus should be protected from infections, while the female dog must tolerate the growing of semi-allografts in her uterus. After birth, newborn puppies are at great risk of developing infectious diseases, because their immune system is in development and immune memory is absent. Passive transfer of immunity through colostrum is fundamental for puppy survival in the first weeks of life, but hampers the development of an active immune response to vaccination. At the end of life, dogs experience a decline in the structure and functional competence of the immune system, compromising the immune responses to novel antigenic challenges, such as infections and vaccines. Therefore, the current article reviews the general processes related to the development of the dog´s immune system, providing an overview of immune activity throughout the dog's life and its implications in canine health, and highlighting priority research goals.

Molecular and restriction fragment length polymorphism analysis of canine parvovirus 2 (CPV-2) in dogs in southeast Anatolia, Turkey

Canine parvovirus-2 (CPV-2) is the aetiological agent of an infectious viral disease of dogs, characterised by diarrhoea and vomiting. Mutations of the CPV-2 genome have generated new variants circulating worldwide. This article reports the molecular analysis of CPV-2 variants collected in the dog population in southeast Anatolia, Turkey. Twenty blood samples previously taken for the laboratory diagnosis of dogs with suspected parvovirus were screened for CPV-2 by polymerase chain reaction (PCR). Of the 20 samples, 18 tested positive for CPV-2. Partial VP2 gene sequencing and restriction fragment length polymorphism (RFLP) analysis revealed CPV-2a (n = 1), CPV-2b (n = 16) and CPV-2c (n = 1) variants. Phylogenetic analysis based on the partial length VP2 gene showed that CPV-2b (n = 15) variants showed sequences clustering separately in the phylogenetic tree. The CPV-2c sample was phylogenetically related to Chinese strains and Indonesia strain, whereas the CPV-2a sample was phylogenetically related to the Portuguese strain. These results, which are the first to demonstrate the presence of CPV-2c in the dog population of southeast Anatolia, Turkey, indicate that CPV-2a/2b/2c variants co-exist in Turkey’s dog population.

Chapparvovirus DNA Found in 4% of Dogs with Diarrhea

Feces from dogs in an unexplained outbreak of diarrhea were analyzed by viral metagenomics revealing the genome of a novel parvovirus. The parvovirus was named cachavirus and was classified within the proposed Chapparvovirus genus. Using PCR, cachavirus DNA was detected in two of nine tested dogs from that outbreak. In order to begin to elucidate the clinical impact of this virus, 2,053 canine fecal samples were screened using real-time PCR. Stool samples from 203 healthy dogs were positive for cachavirus DNA at a rate of 1.47%, while 802 diarrhea samples collected in 2017 and 964 samples collected in 2018 were positive at rates of 4.0% and 4.66% frequencies, respectively (healthy versus 2017-2018 combined diarrhea p-value of 0.05). None of 83 bloody diarrhea samples tested positive. Viral loads were generally low with average real-time PCR Ct values of 36 in all three positive groups. The species tropism and pathogenicity of cachavirus, the first chapparvovirus reported in feces of a placental carnivore, remains to be fully determined.

First detection and phylogenetic analysis of porcine circovirus type 2 in raccoon dogs

Background

Porcine circovirus type 2 (PCV2) is a major emerging virus of porcine circovirus-associated disease (PCVAD), which has brought huge economic losses to the global pig industry. Pigs are well known as the natural reservoir of PCV2. Recently, many researchers have revealed PCV2 could infect many other mammals like mice, calves, minks, dogs and goats. In 2018, our laboratory has admitted six cases of raccoon dogs from Qinhuangdao city of China, which were characterized by inappetence, lethargy, depression, abortion, and sterility.

Results

At last, six raccoon dog-origin PCV2 strains were isolated in this study. Pairwise-sequence comparisons demonstrated that the six raccoon dog-origin PCV2 strains shared a nucleotide similarity of 92.1–99.8% among 40 PCV2 representative strains. Phylogenetic analysis indicated these PCV2 isolates belonged to Chinese epidemic genotypes PCV2b and PCV2d. And aborted or sterile symptom was significantly associated with PCV2 infection in raccoon dogs by the chi-square test (χ² = 87.3, p < 0.001). The retrospective study revealed that raccoon dog-origin PCV2 strains shared 100% sequence similarity with the PCV2 stains isolated from pig farms around these raccoon dog farms, respectively.

Conclusion

In this study, the first supported evidence of PCV2 prevalence in raccoon dog farms of China was documented. PCV2 may be one of the most significant causative agents resulting in the reproductive failure of farmed raccoon dogs, implying that PCV2 could transmit from pigs to raccoon dogs. That indicated that PCV2 cross-species transmission will be a serious threat to China’s fur animal farming industry.

Diagnostics and genotyping of Canine parvovirus type 2 (CPV-2) from disease cases in south-eastern Poland

Canine parvovirus type 2 is one of the most common causes of death among puppies. Despite preventive vaccination, the disease continues to be diagnosed. The aim of the study was to provide a molecular characterization of CPV-2 isolates found in southeastern Poland. Genetic CPV-2 material was isolated from the blood (n=10) and feces (n=50) of infected dogs. The presence of CPV-2 was confirmed by amplification of sequences coding both VP1 and VP2 protein. The products of the PCR reaction with primers amplifying VP2 protein were sequenced and used for genotyping. Bioinformatics analysis of the sequenced PCR product was performed to determine the phylogenetic relationships with variants recorded in the public databases. Based on the analysis of polymorphism in the nucleotide sequence 7 nucleotide variants were detected and assigned into four amino acid groups. Representatives of three groups contained asparagine at amino acid position 426 of the VP2 protein, which is characteristic of CPV-2a. The variant from the fourth group belonged to type CPV-2b. CPV-2a is the dominant antigenic type of CPV-2 in Poland. The pathogen’s high degree of polymorphism is manifested not only by the presence of numerous variants within the type, but also by the presence of representatives of type CPV-2b. Further studies of the molecular epidemiology of CPV-2 are necessary to optimize the effectiveness of preventive measures.

Transmission ecology of canine parvovirus in a multi-host, multi-pathogen system

Understanding multi-host pathogen maintenance and transmission dynamics is critical for disease control. However, transmission dynamics remain enigmatic largely because they are difficult to observe directly, particularly in wildlife. Here, we investigate the transmission dynamics of canine parvovirus (CPV) using state-space modelling of 20 years of CPV serology data from domestic dogs and African lions in the Serengeti ecosystem. We show that, although vaccination reduces the probability of infection in dogs, and despite indirect enhancement of population seropositivity as a result of vaccine shedding, the vaccination coverage achieved has been insufficient to prevent CPV from becoming widespread. CPV is maintained by the dog population and has become endemic with approximately 3.5-year cycles and prevalence reaching approximately 80%. While the estimated prevalence in lions is lower, peaks of infection consistently follow those in dogs. Dogs exposed to CPV are also more likely to become infected with a second multi-host pathogen, canine distemper virus. However, vaccination can weaken this coupling, raising questions about the value of monovalent versus polyvalent vaccines against these two pathogens. Our findings highlight the need to consider both pathogen- and host-level community interactions when seeking to understand the dynamics of multi-host pathogens and their implications for conservation, disease surveillance and control programmes.

First detection and genetic analysis of fox-origin porcine circovirus type 2

Porcine circovirus type 2 (PCV2) is a causative agent of porcine circovirus-associated disease (PCVAD), which is a serious problem in the swine industry worldwide. In recent years, nonporcine-origin PCV2 has attracted more and more attention of the researchers. This study reported on the first identification of PCV2 in farmed foxes with reproductive failure. Three fox-origin PCV2 strains were successfully isolated, sequenced, and designated as FoxHB1, FoxHB2, and FoxHB3 respectively. Pairwise-sequence comparisons of the complete genomes revealed that three fox-origin PCV2 strains had nucleotide identities varied from 91.9% to 99.7% with representative strains of PCV2 different genotypes. Meanwhile, phylogenetic analysis based on complete genomes of 44 PCV2 strains indicated that the fox-origin PCV2 strains belonged to Chinese epidemic genotypes PCV2b and PCV2d. These results provided the first supported evidence that PCV2 could infect foxes, implying that the cross-species transmission of PCV2 would be a big threat to Chinese fur animal-bearing industry.

Origin and genetic diversity of canine parvovirus 2c circulating in Mexico

Canine parvovirus type 2 (CPV-2) emerged in the late 1970 s as a pathogen that is capable of causing high rates of morbidity and mortality in dogs. Currently, three genetic variants circulate worldwide (CPV 2a, 2b, and 2c); however, epidemiological studies have not been conducted in all countries to identify its variants. The objectives of this work were to determine which genotypes of CPV-2 circulate in Mexico and to identify the genetic relationships between CPV-2 sequences from Mexico and those from other parts of the world. Samples from five geographical regions of Mexico were analysed by PCR for identification of CPV-2. Here, 1638 bp of the VP2 gene were amplified and sequenced from 50 CPV-2-positive samples, and a phylogenetic network was assembled using these 50 sequences and 150 others obtained from GenBank, representing different countries around the world. The network showed that the most common genotype circulating in the geographic zones of Mexico was CPV-2c. In the network, the 50 samples were organised into two clusters: cluster I, derived from a group of samples of European origin, which belong to genotype 2c, and cluster II, derived from samples belonging to genotype 2b from the USA. Our data suggest that the CPV-2 strains circulating in Mexico originated from two possible virus introduction events. In addition, high genetic diversity was observed among the CPV-2c-derived sequences, which correspond exclusively to the presence of Mexican CPV-2c haplotypes.

Identification and genetic characterization of a novel parvovirus associated with serum hepatitis in horses in China

A novel equine parvovirus, equine parvovirus-hepatitis (EqPV-H), was first discovered in a horse that died of equine serum hepatitis in the USA in 2018. EqPV-H was shown to be a novel etiological agent associated with equine serum hepatitis. Following this initial report, no additional studies on EqPV-H have been published. In this study, a total of 143 serum samples were collected from racehorses at 5 separate farms in China and were analyzed to detect EqPV-H DNA via nested PCR. The results indicated a high prevalence of EqPV-H (11.9%, 17/143) in the studied animals. In addition, a remarkably high coinfection rate (58.8%, 10/17) with 2 equine flaviviruses (equine hepacivirus and equine pegivirus) was observed in the EqPV-H positive equines. However, all equines tested negative for Theiler’s disease-associated virus, an etiological agent associated with equine serum hepatitis. The genomes of six field EqPV-H strains were sequenced and analyzed, with the results indicating that the Chinese EqPV-H strains have low genetic diversity and high genetic similarity with the USA EqPV-H strain BCT-01. A phylogenetic analysis demonstrated that the Chinese EqPV-H strains clustered with BCT-01 in the genus Copiparvovirus but were distantly related to another equine parvovirus identified in horse cerebrospinal fluid. In addition, liver enzyme levels were detected in the EqPV-H positive serum samples, and all the values were in the normal range, indicating that infection can occur without concurrent liver disease. This study will promote an understanding of the geographical distribution, genetic diversity, and pathogenicity of EqPV-H.

Diagnosis and characterization of canine parvovirus-2 affecting canines of South Gujarat, India

The present study was carried out in the region of South Gujarat, India, to determine the prevalence and predisposing factors of canine parvovirus-2 (CPV-2) infection in acute gastroenteritis of pups. Further, haemagglutination (HA) test, enzyme linked immunosorbent assay (ELISA), polymerase chain reaction (PCR) and rapid immunochromatography test were compared for diagnosis and prevalent CPV-2 types were ascertained. A total of 73 diarrhoea samples were collected and out of those 32, 33 and 35 were found positive via HA, ELISA and PCR, respectively. In rapid test, 26/52 samples were found positive. Among different age-groups, 11/24 and 13/21 animals were positive in pups aged 4–8 and 8–12 weeks, respectively. All but one (34/35) positive samples were from unvaccinated animals. Labrador was found to be the most susceptible breed (n = 13) to infection. Considering PCR as the best test, 47.94% (35/73) prevalence of CPV was recorded. Among PCR positive samples, 3 and 32 belonged to type CPV-2a and CPV-2b, respectively. Type CPV-2c was not detected among the examined samples. Sequencing analysis of 9/10 CPV-2b isolates revealed single nucleotide polymorphism (SNP) (A-G) at position 4106 (alanine to threonine) and suggested the occurrence of mutant, new CPV-2b in this area. As other major pathogen canine coronavirus was detected in 7/38 CPV negative samples. Conclusively, CPV-2 infection was detected in 47.97% cases of AGE of pups which warrants search for other pathogens in the diagnostic procedure. This work is among the few recent reports which depict the occurrence of a novel mutant (new CPV-2b) in India.

Assessment of acute kidney injury in canine parvovirus infection: Comparison of kidney injury biomarkers with routine renal functional parameters

Dogs with naturally occurring canine parvovirus (CPV) infection are at risk of developing acute kidney injury (AKI) due to several factors, including severe dehydration, hypotension and sepsis. Serum creatinine (sCr) and serum urea are insensitive markers for the assessment of early kidney injury. Therefore, the aim of this study was to investigate potential kidney injury in dogs with CPV infection using both routine renal functional parameters and several kidney injury biomarkers. Twenty-two dogs with CPV infection were prospectively enrolled and compared with eight clinically healthy control dogs. Urinary immunoglobulin G (uIgG) and C-reactive protein (uCRP) were measured to document glomerular injury, whereas urinary retinol-binding protein (uRBP) and neutrophil gelatinase-associated lipocalin (uNGAL) served as markers for tubular injury. These biomarkers were compared to routine renal functional parameters, including sCr, serum urea, urinary protein:creatinine ratio (UPC) and urine specific gravity (USG). Dogs with CPV infection had significantly higher concentrations of uIgG, uCRP, uRBP and uNGAL compared to healthy dogs. In contrast, sCr was significantly lower in dogs with CPV infection compared to controls, while serum urea was not significantly different. UPC and USG were both significantly higher in CPV-infected dogs. This study demonstrated that dogs with CPV infection had evidence of AKI, which remained undetected by the routine functional markers sCr and serum urea, but was revealed by UPC, uIgG, uCRP, uRBP and uNGAL. These results emphasize the added value of novel urinary kidney injury biomarkers to detect canine patients at risk of developing AKI.