Isolation and characterization of a novel parvovirus from a red-crowned crane, China, 2021.

BACKGROUND: Parvoviruses are icosahedral, nonenveloped viruses with single-stranded DNA genomes of approximately 5 kb in length. In recent years, parvoviruses have frequently mutated and expanded their host range to cause disease in many wild animals by altering their tissue tropism. Animal infection mainly results in acute enteritis and inflammation of other organs. In this study, we used a viral metagenomic method to detect a novel parvovirus species in a red-crowned crane that died due to severe diarrhea in China. RESULTS: The presence of the viral genome in the kidney, lung, heart, liver, and intestine were confirmed by PCR. Histopathological examination of the intestine showed a large number of infiltrated inflammatory cells. The JL21/10 strain of the red-crowned crane parvovirus was first isolated from the intestine. Whole-genome sequence analysis showed that JL21/10 shared high identity with the red-crowned crane Parvovirinae strains yc-8 at the nucleotide level (96.61%). Phylogenetic analysis of the complete genome and NS1 gene revealed that the JL21/10 strain clustered with strains in chicken and revealed a close genetic relationship with the red-crowned crane parvovirus strains.The complete of VP2 gene analysis showed that JL21/10 shared identity with the red-crowned crane yc-8 strains (97.7%), chicken (55.4%),ducks(31.0%) and geese(30.1%) at the amino acid level. The result showed that red-crowned crane parvovirus may be cross-species transmission to chicken. However, There is little possibility of transmission to ducks and geese. CONCLUSION: This is the first isolation and identification of a parvovirus in red-crowned crane that was associated with severe diarrhea.

Molecular characterization of emerging chicken and turkey parvovirus variants and novel strains in Guangxi, China.

Avian parvoviruses cause several enteric poultry diseases that have been increasingly diagnosed in Guangxi, China, since 2014. In this study, the whole-genome sequences of 32 strains of chicken parvovirus (ChPV) and 3 strains of turkey parvovirus (TuPV) were obtained by traditional PCR techniques. Phylogenetic analyses of 3 genes and full genome sequences were carried out, and 35 of the Guangxi ChPV/TuPV field strains were genetically different from 17 classic ChPV/TuPV reference strains. The nucleotide sequence alignment between ChPVs/TuPVs from Guangxi and other countries revealed 85.2-99.9% similarity, and the amino acid sequences showed 87.8-100% identity. The phylogenetic tree of these sequences could be divided into 6 distinct ChPV/TuPV groups. More importantly, 3 novel ChPV/TuPV groups were identified for the first time. Recombination analysis with RDP 5.0 revealed 15 recombinants in 35 ChPV/TuPV isolates. These recombination events were further confirmed by Simplot 3.5.1 analysis. Phylogenetic analysis based on full genomes showed that Guangxi ChPV/TuPV strains did not cluster according to their geographic origin, and the identified Guangxi ChPV/TuPV strains differed from the reference strains. Overall, whole-genome characterizations of emerging Guangxi ChPV and TuPV field strains will provide more detailed insights into ChPV/TuPV mutations and recombination and their relationships with molecular epidemiological features.

Prevalence of equine parvovirus-hepatitis in healthy broodmares in Ontario, Canada.

Equine parvovirus-hepatitis (EqPV-H) was first reported from the serum and liver tissue of a horse diagnosed with Theiler's disease in the United States in 2018. Theiler's disease, also known as equine serum hepatitis, is a severe hepatitis with fulminant hepatic necrosis. The disease has most frequently been reported following the administration of equine-origin biological products; however, it has also been reported in in-contact horses with no prior biologic administration. EqPV-H has been detected in clinically healthy horses in North America (USA, Canada), Europe (Germany, Austria, Slovenia), Asia (China, South Korea), and South America (Brazil). Previous prevalence studies conducted worldwide have shown the presence of EqPV-H DNA in serum or plasma ranging from 3.2 to 19.8%. This study investigated the prevalence of EqPV-H DNA in 170 healthy broodmares of various breeds located on 37 farms in southern Ontario, Canada. The occurrence of EqPV-H infection was determined by quantitative PCR for EqPV-H DNA in serum samples. The effects of age, breed, season, pregnancy status, and equine herpesvirus-1 (EHV-1) vaccination history on EqPV-H status were also investigated. There was a prevalence of 15.9% (27/170) with viral loads of EqPV-H ranging from detectable to 2900 copies/mL. Statistical analysis showed that increasing age was a significant factor in the detection of EqPV-H DNA. Neither breed, season, pregnancy status, nor EHV-1 vaccination history was significant in predicting EqPV-H infection status.

L'hépatite à parvovirus équin (EqPV-H) a été signalée pour la première fois à partir du sérum et du tissu hépatique d'un cheval diagnostiqué avec la maladie de Theiler aux États-Unis en 2018. La maladie de Theiler, également connue sous le nom d'hépatite sérique équine, est une hépatite sévère avec nécrose hépatique fulminante. La maladie a été le plus souvent rapportée à la suite de l'administration de produits biologiques d'origine équine; cependant, il a également été signalé chez des chevaux en contact sans administration préalable de produit biologique. EqPV-H a été détecté chez des chevaux cliniquement sains en Amérique du Nord (États-Unis, Canada), en Europe (Allemagne, Autriche, Slovénie), en Asie (Chine, Corée du Sud) et en Amérique du Sud (Brésil). Des études de prévalence antérieures menées dans le monde entier ont montré la présence d'ADN EqPV-H dans le sérum ou le plasma allant de 3,2 à 19,8 %. Cette étude a examiné la prévalence de l'ADN EqPV-H chez 170 poulinières en bonne santé de différentes races situées dans 37 fermes du sud de l'Ontario, au Canada. La survenue d'une infection par EqPV-H a été déterminée par PCR quantitative pour l'ADN d'EqPV-H dans des échantillons de sérum. Les effets de l'âge, de la race, de la saison, de l'état de grossesse et des antécédents de vaccination contre l'herpèsvirus équin-1 (EHV-1) sur le statut EqPV-H ont également été étudiés. Il y avait une prévalence de 15,9 % (27/170) avec des charges virales d'EqPV-H allant de détectable à 2900 copies/mL. L'analyse statistique a montré que l'augmentation de l'âge était un facteur significatif dans la détection de l'ADN EqPV-H. Ni la race, ni la saison, ni l'état de grossesse, ni les antécédents de vaccination contre l'EHV-1 n'étaient significatifs pour prédire l'état de l'infection par l'EqPV-H.(Traduit par Docteur Serge Messier).

Isolation, cloning and analysis of parvovirus-specific canine antibodies from peripheral blood B cells.

B-cell cloning methods enable the analysis of antibody responses against target antigens and can be used to reveal the host antibody repertoire, antigenic sites (epitopes), and details of protective immunity against pathogens. Here, we describe improved methods for isolation of canine peripheral blood B cells producing antibodies against canine parvovirus (CPV) capsids by fluorescence-activated cell sorting, followed by cell cloning. We cultured sorted B cells from an immunized dog in vitro and screened for CPV-specific antibody production. Updated canine-specific primer sets were used to amplify and clone the heavy and light chain immunoglobulin sequences directly from the B cells by reverse transcription and PCR. Monoclonal canine IgGs were produced by cloning heavy and light chain sequences into antibody expression vectors, which were screened for CPV binding. Three different canine monoclonal antibodies were analyzed, including two that shared the same heavy chain, and one that had distinct heavy and light chains. The antibodies showed broad binding to CPV variants, and epitopes were mapped to antigenic sites on the capsid. The methods described here are applicable for the isolation of canine B cells and monoclonal antibodies against many antigens.

Antiviral Activity of an Endogenous Parvoviral Element.

Endogenous viral elements (EVEs) are genomic DNA sequences derived from viruses. Some EVEs have open reading frames (ORFs) that can express proteins with physiological roles in their host. Furthermore, some EVEs exhibit a protective role against exogenous viral infection in their host. Endogenous parvoviral elements (EPVs) are highly represented in mammalian genomes, and although some of them contain ORFs, their function is unknown. We have shown that the locus EPV-Dependo.43-ODegus, an EPV with an intact ORF, is transcribed in Octodon degus (degu). Here we examine the antiviral activity of the protein encoded in this EPV, named DeRep. DeRep was produced in bacteria and used to generate antibodies that recognize DeRep in western blots of degu tissue. To test if DeRep could protect against exogenous parvovirus, we challenged cells with the minute virus of mice (MVM), a model autonomous parvovirus. We observed that MVM protein expression, DNA damage induced by replication, viral DNA, and cytopathic effects are reduced when DeRep is expressed in cells. The results of this study demonstrate that DeRep is expressed in degu and can inhibit parvovirus replication. This is the first time that an EPV has been shown to have antiviral activity against an exogenous virus.

Liver virome of a Little Corella (Cacatua sanguinea) reveals coinfection with a novel parvovirus and two beak and feather disease viruses.

Emerging diseases are acknowledged as a growing threat to wildlife, with the continued identification of pathogenic and potentially pathogenic viruses in avian species resulting from ongoing advances in molecular diagnostic techniques. Parvoviruses under the genus Chaphamaparvovirus (subfamily Hamaparvovirinae) are highly divergent. The detection and characterisation of parvoviruses in psittacine birds is limited. This study reports a novel parvovirus, tentatively named psittaciform chaphamaparvovirus 3 (PsChV-3) under the genus Chaphamaparvovirus, identified in an Australian free-ranging little corella (Cacatua sanguinea). The PsChV-3 genome is 4277 bp in length and encompasses four predicted open-reading frames, including two major genes, a nonstructural replicase gene (NS1), and a structural capsid gene (VP1). The NS1 and VP1 genes showed the closest amino acid identities of 78.8% and 69.7%, respectively, with a recently sequenced psittaciform chaphamaparvovirus 2 from Australian Neophema species grass parrots. In addition, the presence of two complete novel beak and feather disease (BFDV) genomes, 1993 and 1868 nt in length, respectively, were detected from the same bird. Both these BFDV genomes contained two bidirectional ORFs encoding the putative Rep and Cap proteins. Phylogenetic analysis showed that the sequenced novel BFDV genomes clustered in a distinct subclade with other BFDVs isolated from Australian cockatoos. This study contributes to the characterisation chaphamaparvoviruses and BFDV in Australian parrots and supports the need for ongoing monitoring and molecular studies into the avian virome in native Australian psittacine bird species.

The Autonomous Parvovirus Minute Virus of Mice Localizes to Cellular Sites of DNA Damage Using ATR Signaling.

Minute Virus of Mice (MVM) is an autonomous parvovirus of the Parvoviridae family that replicates in mouse cells and transformed human cells. MVM genomes localize to cellular sites of DNA damage with the help of their essential non-structural phosphoprotein NS1 to establish viral replication centers. MVM replication induces a cellular DNA damage response that is mediated by signaling through the ATM kinase pathway, while inhibiting induction of the ATR kinase signaling pathway. However, the cellular signals regulating virus localization to cellular DNA damage response sites has remained unknown. Using chemical inhibitors to DNA damage response proteins, we have discovered that NS1 localization to cellular DDR sites is independent of ATM or DNA-PK signaling but is dependent on ATR signaling. Pulsing cells with an ATR inhibitor after S-phase entry leads to attenuated MVM replication. These observations suggest that the initial localization of MVM to cellular DDR sites depends on ATR signaling before it is inactivated by vigorous virus replication.

Bipartite genome and structural organization of the parvovirus Acheta domesticus segmented densovirus.

Parvoviruses (family Parvoviridae) are currently defined by a linear monopartite ssDNA genome, T = 1 icosahedral capsids, and distinct structural (VP) and non-structural (NS) protein expression cassettes within their genome. We report the discovery of a parvovirus with a bipartite genome, Acheta domesticus segmented densovirus (AdSDV), isolated from house crickets (Acheta domesticus), in which it is pathogenic. We found that the AdSDV harbors its NS and VP cassettes on two separate genome segments. Its vp segment acquired a phospholipase A2-encoding gene, vpORF3, via inter-subfamily recombination, coding for a non-structural protein. We showed that the AdSDV evolved a highly complex transcription profile in response to its multipartite replication strategy compared to its monopartite ancestors. Our structural and molecular examinations revealed that the AdSDV packages one genome segment per particle. The cryo-EM structures of two empty- and one full-capsid population (3.3, 3.1 and 2.3 Å resolution) reveal a genome packaging mechanism, which involves an elongated C-terminal tail of the VP, "pinning" the ssDNA genome to the capsid interior at the twofold symmetry axis. This mechanism fundamentally differs from the capsid-DNA interactions previously seen in parvoviruses. This study provides new insights on the mechanism behind ssDNA genome segmentation and on the plasticity of parvovirus biology.

Deciphering the Origin of DNA Viruses (Replication-Associated Parvo-NS1) That Infect Vertebrates from Invertebrate-Infecting Viruses.

DNA replication is a standard and essential function among DNA viruses; however, this functional domain's common ancestor, origin, and evolutionary path in invertebrate- and vertebrate-infecting viruses are not yet fully understood. Here, we present evidence, using a combination of phylogenetic relationships, coevolution, and CLANS (cluster analysis of sequences) analysis, that the parvo-NS1 domain (nonstructural protein NS1, DNA helicase domain) of these DNA viruses that infect vertebrates potentially originated from the invertebrate (Platyhelminthes) parvo-NS1 domain of parvovirus-related sequences (PRSs). Our results suggest that papillomaviruses and the parvovirus subfamilies Densovirinae and Hamaparvovirinae DNA helicase evolved directly from the Platyhelminthes NS1 domain (PRSs). Similarly, the parvovirus subfamily Parvovirinae NS1 domain displayed evolutionary heritage from the PRSs through Hamaparvovirinae. Further, our analysis also clarified that herpesviruses and adenoviruses independently obtained the parvo-NS1 domain from Dependoparvovirus (Parvovirinae). Furthermore, virus-host coevolution analysis revealed that the parvovirus NS1 domain has coevolved with hosts, from flatworms to humans, and it appears that the papillomavirus may have obtained the DNA helicase during the early stages of parvovirus evolution and later led to the development of the DNA helicase of adomavirus and polyomavirus. Finally, herpesviruses and adenoviruses likely inherited the parvo-NS1 domain from Dependoparvovirus in the later stages of evolution. To the best of our knowledge, this is the first evolutionary evidence to suggest that the DNA helicase of viruses that infect vertebrates originated from the invertebrate PRSs. IMPORTANCE DNA replication of DNA viruses is an essential function. This allows DNA replication of viruses to form virus particles. The DNA helicase domain is responsible for this primary function. This domain is present in parvoviruses, papillomaviruses, polyomaviruses, herpesviruses, and adenoviruses. But little is known about the common ancestor, origin, and evolutionary path of DNA helicase in invertebrate- and vertebrate-infecting viruses. Here, we report the possibility of the origin of DNA viruses (DNA helicase) infecting vertebrates from Platyhelminthes (invertebrate) PRSs. Our study established that the parvovirus subfamily Parvovirinae NS1 domain displayed evolutionary heritage from the Platyhelminthes PRSs through Hamaparvovirinae. Furthermore, our study suggests that the papillomavirus DNA helicase may have evolved in the early stages of parvovirus evolution and then led to the development of the adomavirus and polyomavirus. Our study suggests that the herpesviruses and adenoviruses likely inherited the parvo-NS1 domain through gene capture from Dependoparvovirus in the later stages of parvovirus evolution in their hosts.

Molecular detection and characterization of three novel parvoviruses belonging to two different subfamilies in zoo birds.

Birds carry a large number of viruses that may cause diseases in animals or humans. At present, information about the virome of zoo birds is limited. In this study, using viral metagenomics, we investigated the fecal virome of zoo birds collected from a zoo in Nanjing, Jiangsu Province, China. Three novel parvoviruses were obtained and characterized. The genomes of the three viruses are 5,909, 4,411, and 4,233 nt in length, respectively, and contain four or five ORFs. Phylogenetic analysis showed that these three novel parvoviruses clustered with other strains and formed three different clades. Pairwise comparison of NS1 amino acid sequences showed that Bir-01-1 shared 44.30-74.92% aa sequence identity with other parvoviruses belonging to the genus Aveparvovirus, while Bir-03-1 and Bir-04-1 shared less than 66.87% and 53.09% aa sequence identity, respectively, with other parvoviruses belonging to the genus Chaphamaparvovirus. Each of these three viruses was identified as a member of a novel species based on the species demarcation criteria for parvoviruses. These findings broaden our knowledge of the genetic diversity of parvoviruses and provide epidemiological data regarding potential outbreaks of parvovirus disease in birds.

Genomes of the autonomous parvovirus minute virus of mice induce replication stress through RPA exhaustion.

The oncolytic autonomous parvovirus Minute Virus of Mice (MVM) establishes infection in the nuclear environment by usurping host DNA damage signaling proteins in the vicinity of cellular DNA break sites. MVM replication induces a global cellular DNA Damage Response (DDR) that is dependent on signaling by the ATM kinase and inactivates the cellular ATR-kinase pathway. However, the mechanism of how MVM generates cellular DNA breaks remains unknown. Using single molecule DNA Fiber Analysis, we have discovered that MVM infection leads to a shortening of host replication forks as infection progresses, as well as induction of replication stress prior to the initiation of virus replication. Ectopically expressed viral non-structural proteins NS1 and NS2 are sufficient to cause host-cell replication stress, as is the presence of UV-inactivated non-replicative MVM genomes. The host single-stranded DNA binding protein Replication Protein A (RPA) associates with the UV-inactivated MVM genomes, suggesting MVM genomes might serve as a sink for cellular stores of RPA. Overexpressing RPA in host cells prior to UV-MVM infection rescues DNA fiber lengths and increases MVM replication, confirming that MVM genomes deplete RPA stores to cause replication stress. Together, these results indicate that parvovirus genomes induce replication stress through RPA exhaustion, rendering the host genome vulnerable to additional DNA breaks.

A Novel Dependoparvovirus Identified in Cloacal Swabs of Monk Parakeet (Myiopsitta monachus) from Urban Areas of Spain.

The introduction of invasive birds into new ecosystems frequently has negative consequences for the resident populations. Accordingly, the increasing population of monk parakeets (Myiopsitta monachus) in Europe may pose a threat because we have little knowledge of the viruses they can transmit to native naïve species. In this study, we describe a new dependoparvovirus detected by metagenomic analysis of cloacal samples from 28 apparently healthy individuals captured in urban areas of Madrid, Spain. The genomic characterization revealed that the genome encoded the NS and VP proteins typical of parvoviruses and was flanked by inverted terminal repeats. No recombination signal was detected. The phylogenetic analysis showed that it was closely related to a parvovirus isolated in a wild psittacid in China. Both viruses share 80% Rep protein sequence identity and only 64% with other dependoparvoviruses identified in Passeriformes, Anseriformes, and Piciformes and are included in a highly supported clade, which could be considered a new species. The prevalence was very low, and none of the additional 73 individuals tested positive by PCR. These results highlight the importance of exploring the viral genome in invasive species to prevent the emergence of novel viral pathogenic species.

Progress in the study of parvovirus entry pathway.

A group of DNA viruses called parvoviruses that have significant effects on cancer therapy and genetic engineering applications. After passing through the cell membrane to reach the cytosol, it moves along the microtubule toward the nuclear membrane. The nuclear localization signal (NLS) is recognized by importin-beta (impß) and other proteins from the complex outside the nuclear membrane and binds to enter the nucleus via the nuclear pore complex (NPC). There are two main pathways for viruses to enter the nucleus. The classical pathway is through the interaction of imp α and impß with NLS via NPC. The other is the NPC mediated by the combination of impß and it. While the capsid is introduced into the nucleus through classical nuclear transduction, there is also a transient nuclear membrane dissolution leading to passive transport into the nucleus, which has been proposed in recent years. This article mainly discusses several nuclear entry pathways and related proteins, providing a reference for subsequent research on viral entry pathways.

Oral DNA vaccine adjuvanted with cyclic peptide nanotubes induced a virus-specific antibody response in ducklings against goose parvovirus.

BACKGROUND: Cyclic peptide nanotubes (cPNTs) formed from the spontaneous beta-sheet stacking of peptide rings may serve as a safe and effective oral delivery vehicle/adjuvant for DNA vaccines. AIM: In this study, we sought to determine if a DNA vaccine expressing the VP2 protein of goose parvovirus, adjuvanted with cPNTs, may elicit virus-specific antibody response through oral vaccination. MATERIAL AND METHODS: Forty 20-day-old Muscovy ducks were randomly assigned to two groups of 20 ducks each and vaccinated. Ducks were orally vaccinated (Day 0) and boosted (Day 1 and Day 2) or were mock-vaccinated with saline as the negative control. For immunohistochemical staining, the primary antibody used comprised a rabbit anti-GPV antibody, and the secondary antibody was a goat anti-rabbit antibody. Goat-anti-mouse-IgG was used as a tertiary antibody. IgG and IgA antibody titers in serum were analyzed by the GPV virus-coated ELISA. For IgA antibody analysis, intestine lavage was harvested too. RESULTS: A DNA vaccine, coated with cPNTs, can induce a significant antibody response in ducklings. Immunohistochemical staining of tissues from vaccinated ducklings showed that VP2 proteins can be detected in the intestines and livers for up to six weeks, confirming the antigen expression by the DNA vaccine. Antibody analysis found that this vaccine formulation was very efficient at inducing IgA antibodies in the serum and the intestinal tract. CONCLUSION: A DNA vaccine adjuvanted with cPNTs can effectively express the antigen and can significantly induce an antibody response against goose parvovirus through oral vaccination.

Clinico-epidemiological survey of feline parvovirus circulating in three Egyptian provinces from 2020 to 2021.

Feline parvovirus infection, caused by feline parvovirus and canine parvovirus 2, is a highly contagious, life-threatening disease affecting cats. The available epidemiological data on parvovirus infection in cats in Egypt is limited. Therefore, the aim of the current study was to provide data concerning the epidemiological profile of cats infected with parvovirus, including the prevalence of parvovirus infection in cats in three Egyptian provinces (Sohag, Assiut, and Cairo) and the associated risk factors. Using rapid antigen tests of fecal samples and conventional PCR, the overall prevalence of parvovirus infection in cats was found to be 35% (35/100) and 43% (43/100), respectively. Anorexia, bloody diarrhea, severe dehydration, hypothermia, and vomiting were the most common clinical findings significantly associated with parvovirus-infected cats. The geographical location (Sohag) and the season (winter) were both statistically significant risk factors for parvovirus infection. These findings indicate that parvoviruses are circulating in different regions of Egypt. Our study provides baseline epidemiological data for future preventive and control measures against parvovirus infection, as well as highlighting the need for future genomic surveillance studies involving a large study population from various parts of Egypt in order to better shape the epidemiological picture of parvovirus infection.

Novel Chaphamaparvovirus in Insectivorous Molossus molossus Bats, from the Brazilian Amazon Region.

Chaphamaparvovirus (CHPV) is a recently characterized genus of the Parvoviridae family whose members can infect different hosts, including bats, which constitute the second most diverse order of mammals and are described worldwide as important transmitters of zoonotic diseases. In this study, we identified a new CHPV in bat samples from the municipality of Santarém (Pará state, North Brazil). A total of 18 Molossus molossus bats were analyzed using viral metagenomics. In five animals, we identified CHPVs. These CHPV sequences presented the genome with a size ranging from 3797 to 4284 bp. Phylogenetic analysis-based nucleotide and amino acid sequences of the VP1 and NS1 regions showed that all CHPV sequences are monophyletic. They are also closely related to CHPV sequences previously identified in bats in southern and southeast Brazil. According to the International Committee on Taxonomy of Viruses (ICTV) classification criteria for this species (the CHPV NS1 gene region must have 85% identity to be classified in the same species), our sequences are likely a new specie within the genus Chaphamaparvovirus, since they have less than 80% identity with other CHPV described earlier in bats. We also make some phylogenetic considerations about the interaction between CHPV and their host. We suggest a high level of specificity of CPHV and its hosts. Thus, the findings contribute to improving information about the viral diversity of parvoviruses and show the importance of better investigating bats, considering that they harbor a variety of viruses that may favor zoonotic events.

Herpesviruses, polyomaviruses, parvoviruses, papillomaviruses, and anelloviruses in vestibular schwannoma.

Etiology of vestibular schwannoma (VS) is unknown. Viruses can infect and reside in neural tissues for decades, and new viruses with unknown tumorigenic potential have been discovered. The presence of herpesvirus, polyomavirus, parvovirus, and anellovirus DNA was analyzed by quantitative PCR in 46 formalin-fixed paraffin-embedded VS samples. Five samples were analyzed by targeted next-generation sequencing. Viral DNA was detected altogether in 24/46 (52%) tumor samples, mostly representing anelloviruses (46%). Our findings show frequent persistence of anelloviruses, considered normal virome, in VS. None of the other viruses showed an extensive presence, thereby suggesting insignificant role in VS.

A comparison of the Sepsis-2 and Sepsis-3 definitions for assessment of mortality risk in dogs with parvovirus.

OBJECTIVE: To evaluate the use of a modified Sepsis-3 (mSepsis-3) definition compared to the currently used modified Sepsis-2 (mSepsis-2) definition to determine whether the mSepsis-2 or mSepsis-3 stratifications were able to identify populations of dogs ultimately more likely to die from canine parvovirus (CPV) infection. DESIGN: Retrospective, January 2009 to March 2020. SETTING: A private, small animal, urban, referral emergency and specialty hospital. ANIMALS: Fifty-nine client-owned dogs hospitalized for treatment of CPV. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Dogs were divided into mSepsis-2 and mSepsis-3 categories based on the highest level of illness severity reached during hospitalization. Greater illness severity based on mSepsis-2 criteria (ie, sepsis, severe sepsis, septic shock) was associated with an increase in average length of stay (P < 0.001), increase in average cost of stay (P < 0.01), and presence of leukopenia (P < 0.05). An increase in illness severity within the mSepsis-2 criteria was not associated with hyperlactatemia (P = 0.29), presence of neutropenia (P = 0.12), or mortality (P = 0.35). Greater illness severity based on mSepsis-3 criteria (ie, infection only, sepsis, septic shock) was associated with an increase in mortality (P < 0.05), increase in average length of stay (P < 0.001), increase in average cost of stay (P < 0.01), presence of leukopenia (P < 0.01), and presence of neutropenia (P < 0.05). The mSepsis-3 criteria were not associated with the presence of hyperlactatemia (P = 0.68). There was no significant difference between survivors and nonsurvivors in the presence of leukopenia (P = 0.19), neutropenia (P = 0.67), or hyperlactatemia (P = 0.58). CONCLUSIONS: The mSepsis-3 diagnostic criteria appear to better identify dogs with CPV at higher risk for mortality compared to the mSepsis-2 criteria.

Exploring nucleic acid condensation and release from individual parvovirus particles with different physicochemical cues.

In the infection cycle, viruses release their genome in the host cell during uncoating. Here we use a variety of physicochemical procedures to induce and monitor the in vitro uncoating of ssDNA from individual Minute Virus of Mice (MVM) particles. Our experiments revealed two pathways of genome release: i) filamentous ssDNA appearing around intact virus particles when using gradual mechanical fatigue and heating at moderate temperature (50 °C). ii) thick structures of condensed ssDNA appearing when the virus particle is disrupted by mechanical nanoindentations, denaturing agent guanidinium chloride and high temperature (70 °C). We propose that in the case of filamentous ssDNA, when the capsid integrity is conserved, the genome is externalized through one channel of the capsid pores. However, the disruption of virus particles revealed a native structure of condensed genome. The mechanical analysis of intact particles after DNA strands ejection confirm the stabilization role of ssDNA in MVM.