Global distribution, cross-species transmission, and receptor binding of canine parvovirus-2: Risks and implications for humans.

For canine parvovirus -2 (CPV-2), a zoonotic virus capable of cross-species transmission in animals, the amino acid changes of capsid protein VP2 are key factors when binding to other species' transferrin receptors (TfR). CPV-2 variants can spread from felines and canines, for example, to Carnivora, Artiodactyla, and Pholidota species, and CPV-2c variants are essential to spread from Carnivora to Artiodactyla and Pholidota species in particular. In our study, a CPV-2a variant maintained a relatively stable trend, and the proportion of CPV-2c gradually rose from 1980 to 2021. The VP2 amino acid sequence analysis showed that five amino acid mutations at 426E/D, 305H/D, and 297S may be necessary for the virus to bind to different host receptors. Meanwhile, receptor-binding loop regions and amino acid sites 87 L, 93 N, 232I, and 305Y were associated with CPV-2 cross-species transmission. The homology of TfRs in different hosts infected with CPV-2 ranged from 77.2 % to 99.0 %, and from pig to feline, canine, and humans was 80.7 %, 80.4 %, and 77.2 %, respectively. The amino acid residues of TfRs involved in the viral binding in those hosts are highly conserved, which suggests that CPV-2 may be capable of pig-to-human transmission. Our analysis of the origin, evolutionary trend, cross-species transmission dynamics, and genetic characteristics of CPV-2 when binding to host receptors provides a theoretical basis for further research on CPV-2's mechanism of cross-species transmission and for establishing an early warning and monitoring mechanism for the possible threat of CPV-2 to animal-human public security.

Opportunistic sampling of yellow canary (Crithagra flaviventris) has revealed a high genetic diversity of detected parvoviral sequences.

Parvoviruses are known to be significant viral pathogens that infect a wide range of species globally. However, little is known about the parvoviruses circulating in Australian birds, including yellow canaries. Here, we present four parvoviral sequences including three novel parvoviruses detected from 10 yellow canaries (Crithagra flaviventris), named canary chaphamaparvovirus 1 and -2 (CaChPV1 and CaChPV2), canary dependoparvovirus 1 and -2 (CaDePV1 and CaDePV2). The whole genome sequences of CaChPV1, CaChPV2, CaDePV1, and CaDePV2 showed the highest identity with other parvoviruses at 76.4%, 75.9%, 84.0%, and 59.1%, respectively. Phylogenetic analysis demonstrated that CaChPV1 and CaChPV2 were clustered within the genus Chaphamaparvovirus. Meanwhile, CaDePV1 and CaDePV2 fall within the genus Dependoparvovirus and have the closest evolutionary relationship to the bird-associated dependoparvoviruses. Overall, this study enriched our understanding of the genetic diversity among avian parvoviruses within the Parvoviridae family.

Development of a time-resolved fluorescence immunoassay kit for detecting canine coronavirus and parvovirus through double labeling.

OBJECTIVE: Canine enteric coronavirus (CCV) and canine parvovirus type 2 (CPV-2) are the main pathogens responsible for acute gastroenteritis in dogs, and both single and mixed infections are common. This study aimed to establish a double-labeling time-resolved fluorescence immunoassay (TRFIA) to test and distinguish CCV and CPV-2 diseases. METHODS: A sandwich double-labeling TRFIA method was established and optimized using europium(III) (Eu3+)/samarium(III) (Sm3+) chelates. CCV/CPV-2 antigens were first captured by the immobilized antibodies. Then, combined with Eu3+/Sm3+-labeled paired antibodies, the Eu3+/Sm3+ fluorescence values were detected after dissociation to calculate the CCV/CPV-2 ratios. The performance, clinical performance and methodology used for laboratory (sensitivity, specificity, accuracy and stability) testing were evaluated. RESULTS: A double-label TRFIA for CCV and CPV-2 detection was optimized and established. The sensitivity of this TRFIA kit was 0.51 ng/mL for CCV and 0.80 ng/mL for CPV-2, with high specificity for CCV and CPV-2. All the accuracy data were less than 10%, and the recovery ranged from 101.21 to 110.28%. The kits can be temporarily stored for 20 days at 4 °C and can be stored for 12 months at temperatures less than - 20 °C. Based on a methodology comparison of 137 clinically suspected patients, there was no statistically significant difference between the TRFIA kit and the PCR method. Additionally, for CCV detection, the clinical sensitivity was 95.74%, and the clinical specificity was 93.33%. For CPV-2 detection, the clinical sensitivity was 92.86%, and the clinical specificity was 96.97%. CONCLUSION: In this study, a double-label TRFIA kit was prepared for CCV and CPV-2 detection with high laboratory sensitivity, specificity, accuracy, stability, clinical sensitivity and specificity. This kit provides a new option for screening/distinguishing between CCV and CPV-2 and may help improve strategies to prevent and control animal infectious diseases in the future.

Detection and genetic characterization of circulating canine parvovirus from stray dogs in Shanghai, China.

Canine parvovirus (CPV) is the main cause of viral diarrhea in dogs. CPV became a global disease in 1978 and was endemic all over the world. CPV-2 was the first strain to be identified, but with genetic mutations, new genotypes such as CPV-2a/2b/2c/new-2a/new-2b have emerged. In this study, 128 fecal samples of stray dogs suspected of CPV-2 infection were collected from January to March 2021 in Shanghai, China. All samples were screened by PCR and further analyzed by VP2 gene. The positive rate of CPV-2 was 9.4% (12/128), of which 6 CPV-2 isolates were successfully isolated. Phylogenetic tree analysis showed that 4 isolates were CPV-2c genotype and 2 were new-CPV-2b genotype. VP-2 is a key protein that determines the antigenic properties, host range and receptor binding of cpv-2. The results of VP2 amino acid sequence analysis in this study showed that the CPV-2c isolated strain was the same as the previous strains reported in China, including F267Y, Y324I, Q370R and A5G mutations in addition to the typical N426E mutations. Similarly, in addition to the conventional N426D, S297A, F267Y and Y324I mutations, the new CPV-2b isolate also had a new mutation of T440A. This study further confirmed the prevalence of CPV-2c and new-CPV-2b in Shanghai, and also found a new mutation site of new-CPV-2c, which provided a theoretical basis for further enriching the epidemiological data of CPV-2 in Shanghai, as well as the development of vaccines and the prevention and control of the disease.

NS1-mediated enhancement of MVC transcription and replication promoted by KAT5/H4K12ac.

Histone modifications function in both cellular and viral gene expression. However, the roles of acetyltransferases and histone acetylation in parvoviral infection remain poorly understood. In the current study, we found the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), promoted the replication and transcription of parvovirus minute virus of canines (MVC). Notably, the expression of host acetyltransferases KAT5, GTF3C4, and KAT2A was increased in MVC infection, as well as H4 acetylation (H4K12ac). KAT5 is not only responsible for H4K12ac but also crucial for viral replication and transcription. The viral nonstructural protein NS1 interacted with KAT5 and enhanced its expression. Further study showed that Y44 in KAT5, which may be tyrosine-phosphorylated, is indispensable for NS1-mediated enhancement of KAT5 and efficient MVC replication. The data demonstrated that NS1 interacted with KAT5, which resulted in an enhanced H4K12ac level to promote viral replication and transcription, implying the epigenetic addition of H4K12ac in viral chromatin-like structure by KAT5 is vital for MVC replication.IMPORTANCEParvoviral genomes are chromatinized with host histones. Therefore, histone acetylation and related acetyltransferases are required for the virus to modify histones and open densely packed chromatin structures. This study illustrated that histone acetylation status is important for MVC replication and transcription and revealed a novel mechanism that the viral nonstructural protein NS1 hijacks the host acetyltransferase KAT5 to enhance histone acetylation of H4K12ac, which relies on a potential tyrosine phosphorylation site, Y44 in KAT5. Other parvoviruses share a similar genome organization and coding potential and may adapt a similar strategy for efficient viral replication and transcription.

Sensitivity of lateral flow technique for diagnosis of canine parvovirus.

In this study, we devised a nanogold lateral flow immunoassay (LFA-CPV antigen test) for detecting canine parvovirus (CPV) in living attenuated CPV vaccines. We conducted instrumental characterization of the prepared nanogold particles and the developed LFA-CPV antigen test was rigorously evaluated for its performance verification including limit of detection, sensitivity, specificity, selectivity and accuracy. The LFA-CPV antigen test demonstrated strong performance when assessed against qPCR using different batches of live attenuated CPV vaccines, indicated a sensitivity of 96.4%, specificity of 88.2%, and an overall accuracy of 95%. These results suggest that the developed LFA-CPV antigen test could serve as a viable alternative for evaluation live attenuated CPV vaccines, and provide it as a point of care test for CPV diagnosis, offering a potential substitute for traditional laboratory methods, particularly qPCR.

Clinical and inflammatory response to antiviral treatments in dogs with parvoviral enteritis.

BACKGROUND: Canine parvoviral enteritis (CPE) is a fatal disease worldwide. The treatment of CPE is based mainly on supportive and symptomatic treatment. Antiviral addition to the treatment may result in a higher survival. OBJECTIVES: This study evaluated the effects of antiviral treatments with a standardized treatment (ST) on the clinical and inflammatory response of dogs with naturally occurring CPE. METHODS: Twenty-eight dogs with CPE caused by canine parvovirus type 2 were divided randomly into treatment groups. The ST group received fluid, antibiotic, antiemetic, and deworming treatments. The antiviral treatment groups received the same ST with an additional antiviral drug, recombinant feline interferon omega (rFeIFN-ω), oseltamivir (OSEL) or famciclovir (FAM). RESULTS: Compared to the healthy control, the tumor necrosis factor-α, interleukin-1ß, interferon (IFN)-α, IFN-γ, haptoglobin, and C-reactive protein values were high (p < 0.05) on day zero. At presentation, mild lymphopenia, neutropenia, and a high neutrophil to lymphocyte (LYM) ratio (NLR) were also observed. Adding rFeIFN-ω to the ST produced the best improvement in the clinical score with a decreased NLR, while leucocytes remained low and inflammatory markers stayed high on day three. The survival rates of the groups were 85.7% in ST+IFN, 71.4% in ST+OSEL, 71.4% in ST+FAM, and 57.1% in ST groups on day seven. CONCLUSIONS: Antiviral drugs may be valuable in treating CPE to improve the clinical signs and survival. In addition, the decrease in NLR in favor of LYM may be an indicator of the early prognosis before the improvement of leukocytes, cytokines, and acute phase proteins in CPE.

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.

First detection and genetic characterization of canine bufavirus in domestic dogs, Thailand.

Canine bufavirus (CBuV) was reported in domestic dogs worldwide. We conducted a survey of canine bufavirus in domestic dogs in Thailand from September 2016 to October 2022. Rectal swab samples (n = 531) were collected from asymptomatic dogs and dogs with gastroenteritis signs. The samples were tested for CBuV using PCR with specific primers to the VP1/VP2 gene, and 9.42% (50/531) was CBuV positive. Our findings showed that CBuVs could be detected in both symptomatic and healthy dogs. The Thai CBuVs were found in dogs from different age groups, with a significant presence in those under 1 year (12.60%) and dogs aged 1-5 years (7.34%) (p < 0.05), suggesting a high prevalence of Thai CBuVs in dogs under 5 years of age. We performed complete genome sequencing (n = 15) and partial VP1/VP2 sequencing (n = 5) of Thai CBuVs. Genetic and phylogenetic analyses showed that whole genomes of Thai CBuVs were closely related to Chinese and Italian CBuVs, suggesting the possible origin of Thai CBuVs. The analysis of VP1 and VP2 genes in Thai CBuVs showed that 18 of them were placed in subgroup A, while only 2 belonged to subgroup B. This study is the first to report the detection and genetic characterization of CBuVs in domestic dogs in Thailand. Additionally, surveillance and genetic characterization of CBuVs in domestic animals should be further investigated on a larger scale to elucidate the dynamic, evolution, and distribution of CBuVs.

Molecular Survey on Porcine Parvoviruses (PPV1-7) and Their Association with Major Pathogens in Reproductive Failure Outbreaks in Northern Italy.

Successful reproductive performance is key to farm competitiveness in the global marketplace. Porcine parvovirus 1 (PPV1) has been identified as a major cause of reproductive failure, and since 2001 new species of porcine parvoviruses, namely PPV2-7, have been identified, although their role is not yet fully understood yet. The present study aimed to investigate PPVs' presence in reproductive failure outbreaks occurring in 124 farms of northern Italy. Fetuses were collected from 338 sows between 2019 and 2021 and tested for PPVs by real-time PCR-based assays and for other viruses responsible for reproductive disease. At least one PPV species was detected in 59.7% (74/124) of the tested farms. In order, PPV1, PPV5, PPV6, PPV7 and PPV4 were the most frequently detected species, whereas fewer detections were registered for PPV2 and PPV3. Overall, the new PPV2-7 species were detected in 26.6% (90/338) of the cases, both alone or in co-infections: PCV-2 (7.1%, 24/338), PCV-3 (8.2%, 28/338), and PRRSV-1 (6.2%, 21/338) were frequently identified in association with PPVs. Single PPVs detections or co-infections with other agents commonly responsible for reproductive failure should encourage future studies investigating their biological, clinical, and epidemiological role, for a better preparedness for potential emerging challenges in intensive pig production.

Early administration of canine parvovirus monoclonal antibody prevented mortality after experimental challenge.

OBJECTIVE: To evaluate the effectiveness of canine parvovirus monoclonal antibody (CPMA) as a treatment against canine parvovirus (CPV-2)-induced mortality and to support USDA product licensure. ANIMALS: 28 purpose-bred Beagle dogs aged 8 weeks were randomized to the treated (n = 21) or control (7) group. METHODS: Dogs were challenged intranasally with 104.2 TCID50 virulent CPV-2b on Day 0 and monitored for 14 days for fecal viral shed and clinical disease. All dogs began shedding CPV-2 on Day 4 and were treated intravenously with a single dose of either CPMA (0.2 mL/kg) or saline (equal volume). No additional treatments were given to either group. Feces and sera were collected for quantitative analysis of fecal viral shed (hemagglutination) and antibody responses (hemagglutination inhibition and dot-blot ELISA), respectively. Dogs were monitored twice daily for parameters including lymphopenia, fever, vomiting, abnormal feces, inappetence, and lethargy. Humane endpoints triggered euthanasia by a veterinarian masked to treatment groups. The primary outcome variable was prevention of mortality as compared to controls. RESULTS: Mortality was prevented in all CPMA-treated dogs compared to 57% mortality in the control group (P = .0017, Fisher exact test). Canine parvovirus monoclonal antibody-treated dogs also experienced less severe and/or shorter durations of diarrhea, fever, vomiting, CPV-2 shedding in feces, and lymphopenia. Both groups showed similar immunoglobulin M responses as measured by semiquantitative analysis. CLINICAL RELEVANCE: Intravenous administration of CPMA can effectively improve clinical outcome when administered early in CPV-2 disease. Canine parvovirus monoclonal antibody treatment after proven infection does not interfere with adaptive immunity.

Identification and in vitro characterization of a novel porcine parvovirus 6 in Russia.

Porcine parvovirus 6 (PPV6) was first identified in aborted swine fetuses in China in 2014. Since its identification, an increased number of PPV6 cases have been reported in many countries with developed pig breeding. In this study, the first identification of porcine parvovirus 6 in Russia, its phylogenetic analysis, and its characterization in vitro are reported. During the investigation, 521 serum samples collected from pigs of different ages from seven regions of the Russian Federation were tested. In four regions, the DNA of the virus was detected. The overall prevalence of porcine parvovirus 6 in Russia was 9.4%. Fattening pigs were the group with the most frequent detection of the virus genome. Phylogenetic analysis of the Russian isolate detected in a domestic boar indicated high homology with strains from Spain. In vitro studies revealed that the most promising cell cultures for PPV6 isolation are SPEV and SK. Our results demonstrated that PPV6 induced typical apoptotic features in cells, including DNA fragmentation, chromatin margination, nuclear condensation, pyknosis of nuclei, symplast formation, and various pathological mitoses.

Canine bufavirus (Carnivore protoparvovirus-3) infection in dogs with respiratory disease.

Canine bufavirus (CBuV) or Carnivore protoparvovirus-3, a nonenveloped DNA virus belonging to the genus Protoparvovirus, family Parvoviridae, has been identified in dogs with respiratory and enteric diseases. Although CBuV detection has been reported in multiple countries, descriptions of pathologic findings associated with infection have not yet been provided. In this study, the authors necropsied 14 dogs (12 puppies and 2 adult dogs) from a breeding colony that died during multiple outbreaks of respiratory diseases. Postmortem investigations revealed extensive bronchointerstitial pneumonia with segmental type II pneumocyte hyperplasia in all necropsied puppies but less severe lesions in adults. With negative results of common pathogen detection by ancillary testing, CBuV DNA was identified in all investigated dogs using a polymerase chain reaction (PCR). Quantitative PCR demonstrated CBuV DNA in several tissues, and in situ hybridization (ISH) indicated CBuV tissue localization in the lung, tracheobronchial lymph node, and spinal cord, suggesting hematogenous spread. Dual CBuV ISH and cellular-specific immunohistochemistry were used to determine the cellular tropism of the virus in the lung and tracheobronchial lymph node, demonstrating viral localization in various cell types, including B-cells, macrophages, and type II pneumocytes, but not T-cells. Three complete CBuV sequences were successfully characterized and revealed that they clustered with the CBuV sequences obtained from dogs with respiratory disease in Hungary. No additional cases were identified in small numbers of healthy dogs. Although association of the bufavirus with enteric disease remains to be determined, a contributory role of CBuV in canine respiratory disease is possible.

Seroprevalence, Blood Chemistry, and Patterns of Canine Parvovirus, Distemper Virus, Plague, and Tularemia in Free-Ranging Coyotes (Canis latrans) in Northern New Mexico, USA.

Wildlife diseases have implications for ecology, conservation, human health, and health of domestic animals. They may impact wildlife health and population dynamics. Exposure rates of coyotes (Canis latrans) to pathogens such as Yersinia pestis, the cause of plague, may reflect prevalence rates in both rodent prey and human populations. We captured coyotes in north-central New Mexico during 2005-2008 and collected blood samples for serologic surveys. We tested for antibodies against canine distemper virus (CDV, Canine morbillivirus), canine parvovirus (CPV, Carnivore protoparvovirus), plague, tularemia (Francisella tularensis), and for canine heartworm (Dirofilaria immitis) antigen. Serum biochemistry variables that fell outside reference ranges were probably related to capture stress. We detected antibodies to parvovirus in 32/32 samples (100%), and to Y. pestis in 26/31 (84%). More than half 19/32 (59%) had antibodies against CDV, and 5/31 (39%) had antibodies against F. tularensis. We did not detect any heartworm antigens (n = 9). Pathogen prevalence was similar between sexes and among the three coyote packs in the study area. Parvovirus exposure appeared to happen early in life, and prevalence of antibodies against CDV increased with increasing age class. Exposure to Y. pestis and F. tularensis occurred across all age classes. The high coyote seroprevalence rates observed for CPV, Y. pestis, and CDV may indicate high prevalence in sympatric vertebrate populations, with implications for regional wildlife conservation as well as risk to humans via zoonotic transmission.

Development and application of a multiplex PCR method for the simultaneous detection of goose parvovirus, waterfowl reovirus, and goose astrovirus in Muscovy ducks.

A multiplex polymerase chain reaction (PCR) method was developed to detect and distinguish goose parvovirus (GPV), waterfowl reovirus (WRV), and goose astrovirus (GAstV). Three pairs of primers were designed based on conserved regions in the genomic sequences of these enteric viruses and were used to specifically amplify targeted fragments of 493 bp from the viral protein 3 (VP3) gene of GPV, 300 bp from the sigma A-encoding gene of WRV, and 156 bp from the capsid protein-encoding gene of GAstV. The results showed that the primers can specifically amplify target fragments, without any cross-amplification with other viruses, indicating that the method had good specificity. A sensitivity test showed that the detection limit of the multiplex PCR method was 1 × 103 viral copies. A total of 102 field samples from Muscovy ducks with clinically suspected diseases were evaluated using the newly developed multiplex PCR method. The ratio of positive samples to total samples for GPV, WRV, and GAstV was 73.53% (75/102) for multiplex PCR and was 73.53% (75/102) for routine PCR. Seventy-five positive samples were detected by both methods, for a coincidence ratio of 100%. This multiplex PCR method can simultaneously detect GPV, WRV, and GAstV, which are associated with viral enteritis, thereby providing a specific, sensitive, efficient, and accurate new tool for clinical diagnosis and laboratory epidemiological investigations.

Survey of Common Infectious Diseases in Urban Foxes (Vulpes spp.) in Southeastern Iran.

The red fox (Vulpes vulpes) is one of the most common species of wild Canidae and is relatively abundant in Iran. Foxes (Vulpes spp.) transmit many zoonotic diseases, the most important of which are visceral leishmaniasis, rabies, hydatidosis, toxocariasis, and trichinellosis. In this study, visceral leishmaniasis, rabies, ectoparasites, canine gastrointestinal helminths, dermatophytosis, distemper, parvovirus infection, and heartworm infections were evaluated among live-trapped and rescued foxes injured by traffic road accidents referred to the teaching hospital of Kerman, Iran, veterinary faculty. Skin scraping and direct microscopic examination were used to detect ectoparasites and dermatophytosis. Immunochromatography rapid kits were used to detect dirofilariasis, parvovirus infection, and distemper. Necropsy was used to check for gastrointestinal parasites. Rabies and visceral leishmaniosis were screened for with direct fluorescent antibody test and ELISA methods, respectively. Gastrointestinal helminth infections, including Toxocara canis, Taenia taeniaeformis, Dipylidium caninum, Joyeuxiella echinorhyncoids, Toxascaris leonina, Taenia hydatigena, Echinococcus granulosus, Rictolaria spp., Oxynema spp., Macracanthorhynchus hirudinaceus, and Physaloptera spp., were detected. Skin scrapings showed dermatophytosis and various ectoparasites, including Rhipicephalus sanguineus, Ctenocephalides canis and Ctenocephalides felis, and Sarcoptes scabiei, in foxes with dermal lesions. Distemper and parvovirus infection (26.66%) were the common viral diseases, and rabies infection rate was quite high (16.66%). Dirofilariasis and leishmaniasis were detected in 10% of the population. This study showed that urban foxes which often cohabit with humans and domestic animals are carriers of many different pathogens. This interaction may facilitate indirect cross-species transmission of zoonotic disease. Periodic health monitoring and multidisciplinary cooperation for the diagnosis, control, and prevention of these zoonoses is highly recommended.

The Novel Porcine Parvoviruses: Current State of Knowledge and Their Possible Implications in Clinical Syndromes in Pigs.

Parvoviruses (PVs) affect various animal species causing different diseases. To date, eight different porcine parvoviruses (PPV1 through PPV8) are recognized in the swine population, all of which are distributed among subfamilies and genera of the Parvoviridae family. PPV1 is the oldest and is recognized as the primary agent of SMEDI, while the rest of the PPVs (PPV2 through PPV8) are called novel PPVs (nPPVs). The pathogenesis of nPPVs is still undefined, and whether these viruses are putative disease agents is unknown. Structurally, the PPVs are very similar; the differences occur mainly at the level of their genomes (ssDNA), where there is variation in the number and location of the coding genes. Additionally, it is considered that the genome of PVs has mutation rates similar to those of ssRNA viruses, that is, in the order of 10-5-10-4 nucleotide/substitution/year. These mutations manifest mainly in the VP protein, constituting the viral capsid, affecting virulence, tropism, and viral antigenicity. For nPPVs, mutation rates have already been established that are similar to those already described; however, within this group of viruses, the highest mutation rate has been reported for PPV7. In addition to the mutations, recombinations are also reported, mainly in PPV2, PPV3, and PPV7; these have been found between strains of domestic pigs and wild boars and in a more significant proportion in VP sequences. Regarding affinity for cell types, nPPVs have been detected with variable prevalence in different types of organs and tissues; this has led to the suggestion that they have a broad tropism, although proportionally more have been found in lung and lymphoid tissue such as spleen, tonsils, and lymph nodes. Regarding their epidemiology, nPPVs are present on all continents (except PPV8, only in Asia), and within pig farms, the highest prevalences detecting viral genomes have been seen in the fattener and finishing groups. The relationship between nPPVs and clinical manifestations has been complicated to establish. However, there is already some evidence that establishes associations. One of them is PPV2 with porcine respiratory disease complex (PRDC), where causality tests (PCR, ISH, and histopathology) lead to proposing the PPV2 virus as a possible agent involved in this syndrome. With the other nPPVs, there is still no clear association with any pathology. These have been detected in different systems (respiratory, reproductive, gastrointestinal, urinary, and nervous), and there is still insufficient evidence to classify them as disease-causing agents. In this regard, nPPVs (except PPV8) have been found to cause porcine reproductive failure (PRF), with the most prevalent being PPV4, PPV6, and PPV7. In the case of PRDC, nPPVs have also been detected, with PPV2 having the highest viral loads in the lungs of affected pigs. Regarding coinfections, nPPVs have been detected in concurrence in healthy and sick pigs, with primary PRDC and PRF viruses such as PCV2, PCV3, and PRRSV. The effect of these coinfections is not apparent; it is unknown whether they favor the replication of the primary agents, the severity of the clinical manifestations, or have no effect. The most significant limitation in the study of nPPVs is that their isolation has been impossible; therefore, there are no studies on their pathogenesis both in vitro and in vivo. For all of the above, it is necessary to propose basic and applied research on nPPVs to establish if they are putative disease agents, establish their effect on coinfections, and measure their impact on swine production.

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.

Noticeable immune dysregulation-and-suppression in parvovirus affected dogs.

Canine parvovirus type 2 (CPV-2) is one of the most common causes of infectious diarrhea in small animals, with high mortality and morbidity. Information on the specific treatment option(s) for CPV diseases (CPVD) is unachievably little. So, the treatment is mainly supportive one. Disruption of dog's innate immune system in viral diseases simply occurs; presumably, the CPV-2 may change the level of some TLRs, interleukins, CD4 and CD8 in the leukocytes of CPVD dogs, and disruptive activities of these immune molecules might be attributable to severe CPVD in dogs. Study on the role of the key immune molecules in CPVD is rare. Herein, by conducting and relating the clinical, para-clinical, immunological and molecular diagnostic tests, we tried to establish how some key immune molecules behave in blood of parvovirus affected dogs. As such, in the 1st study, the mRNA levels of TLR2, TLR4, TLR9, IL-1ß, IL-6, CD4 and CD8 genes in the leukocytes of CPVD were assessed with quantitative (q)RT-PCR along with CPV-2 detection by rapid immunochromatography and PCR tests. In a 2nd study, the same measurements as in the 1st study were evaluated in two groups of mild versus severe clinical signs of CPVD. Both in the 1st and the 2nd studies leukopenia, much more pronounced in the severe CPVD, and immune dysregulation were observed. In the 1st study, a noticeable increase in the mRNA levels of TLR2 and TLR4 was detected with a slight decrease in TLR9 and a significant decrease in the expression of IL-1ß, IL-6, CD4 and CD8 in leukocytes of CPV-infected dogs. Compared to the mild CPVD, the intense of downregulating effects on those immune molecules in the 2nd study was remarkably much more pronounced in the severe CPVD. Overall, it proves strong immune dysregulation and suppression/incompetence and potential T-cells exhaustion in severely CPV-2-affected dogs. Technically and clinically, this would be substantially applicable in canine medicine. By targeting those key immune molecules and their signaling pathways, new clinicodiagnostic approaches for CPVD can be evolved, and biotechnicoclinically this would be substantially applicable in all physiopathological conditions of dogs.

Detection and genetic evolution analysis of porcine parvovirus type 7 (PPV7) in Fujian Province.

Porcine parvovirus (PPV) is an important pathogen causing reproductive disorders in sows, with clinical symptoms including stillbirth, mummified fetuses, embryonic dysplasia and death, and sow infertility. Porcine parvovirus 7 (PPV7) is a recently discovered type of PPV and its widespread distribution and rapid evolution has caused huge economic losses in the pig industry. To investigate the molecular epidemiology of PPV7 in Fujian Province, China, we collected 491 blood samples and 72 tissue samples from diseased pigs in large-scale pig farms across selected areas of Fujian Province from 2019 to 2022. PPV7 infection was determined using real-time quantitative PCR, and positive samples underwent whole-genome amplification, sequencing, and subsequent homology, phylogenetic, and recombination analyses. The PPV7 positive detection rate was 25.73% (145/563) in Fujian Province, among which the positive rate of blood and tissue samples was 26.47% (130/491) and 20.83% (15/72), respectively. The nucleotide sequence homology among the 29 PPV7 whole-genome sequences obtained in this study was 90.0%-97.2%, whereas that with 128 reference strains from China and other countries was 88.9%-98.1%. Six strains had partial nucleotide deletions or insertions. Phylogenetic analysis based on the whole-genome sequences classified the 29 PPV7 strains and 128 reference strains into eight subtypes (PPV7a-PPV7h), and PPV7h was the predominant subtype in Fujian Province. Recombination analysis revealed evidence of inferred recombination events in the genomes of four strains. This study provides significant insights into the molecular characteristics of PPV7 in Fujian Province and serves as a crucial foundation for further advancements in PPV7 prevention and control strategies.