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1.
J Virol ; 94(14)2020 07 01.
Article in English | MEDLINE | ID: mdl-32404522

ABSTRACT

Autonomously replicating subgenomic Bungowannah virus (BuPV) RNAs (BuPV replicons) with deletions of the genome regions encoding the structural proteins C, ERNS, E1, and E2 were constructed on the basis of an infectious cDNA clone of BuPV. Nanoluciferase (Nluc) insertion was used to compare the replication efficiencies of all constructs after electroporation of in vitro-transcribed RNA from the different clones. Deletion of C, E1, E2, or the complete structural protein genome region (C-ERNS-E1-E2) prevented the production of infectious progeny virus, whereas deletion of ERNS still allowed the generation of infectious particles. However, those ΔERNS viral particles were defective in virus assembly and/or egress and could not be further propagated for more than three additional passages in porcine SK-6 cells. These "defective-in-third-cycle" BuPV ΔERNS mutants were subsequently used to express the classical swine fever virus envelope protein E2, the N-terminal domain of the Schmallenberg virus Gc protein, and the receptor binding domain of the Middle East respiratory syndrome coronavirus spike protein. The constructs could be efficiently complemented and further passaged in SK-6 cells constitutively expressing the BuPV ERNS protein. Importantly, BuPVs are able to infect a wide variety of target cell lines, allowing expression in a very wide host spectrum. Therefore, we suggest that packaged BuPV ΔERNS replicon particles have potential as broad-spectrum viral vectors.IMPORTANCE The proteins NPRO and ERNS are unique for the genus Pestivirus, but only NPRO has been demonstrated to be nonessential for in vitro growth. While this was also speculated for ERNS, it has always been previously shown that pestivirus replicons with deletions of the structural proteins ERNS, E1, or E2 did not produce any infectious progeny virus in susceptible host cells. Here, we demonstrated for the first time that BuPV ERNS is dispensable for the generation of infectious virus particles but still important for efficient passaging. The ERNS-defective BuPV particles showed clearly limited growth in cell culture but were capable of several rounds of infection, expression of foreign genes, and highly efficient trans-complementation to rescue virus replicon particles (VRPs). The noncytopathic characteristics and the absence of preexisting immunity to BuPV in human populations and livestock also provide a significant benefit for a possible use, e.g., as a vector vaccine platform.


Subject(s)
Pestivirus Infections/virology , Pestivirus/physiology , RNA, Viral , Viral Envelope Proteins/metabolism , Virus Replication , Gene Deletion , Gene Expression , Genes, Reporter , Genetic Engineering , Host-Pathogen Interactions , Pestivirus Infections/immunology , Replicon , Viral Envelope Proteins/genetics , Virion , Virus Assembly
2.
Arch Virol ; 166(10): 2733-2741, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34322722

ABSTRACT

Congenital tremor (CT) type A-II in piglets is a worldwide disease caused by an emerging atypical porcine pestivirus (APPV). Preparation and evaluation of vaccines in laboratory animals is an important preliminary step toward prevention and control of the disease. Here, virus-like particles (VLPs) of APPV were prepared and VLPs vaccine was evaluated in BALB/c mice. Purified Erns and E2 proteins expressed in E. coli were allowed to self-assemble into VLPs, which had the appearance of hollow spherical particles with a diameter of about 100 nm by transmission electron microscopy (TEM). The VLPs induced strong antibody responses and reduced the viral load in tissues of BALB/c mice. The data from animal challenge experiments, RT-PCR, and immunohistochemical analysis demonstrated that BALB/c mice are an appropriate laboratory model for APPV. These results suggest the feasibility of using VLPs as a vaccine for the prevention and control of APPV and provide useful information for further study of APPV in laboratory animals.


Subject(s)
Pestivirus Infections/prevention & control , Pestivirus/immunology , Vaccination/veterinary , Virus Replication/drug effects , Animals , Antibodies, Viral/blood , Disease Models, Animal , Mice , Mice, Inbred BALB C , Pestivirus Infections/virology , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Swine , Swine Diseases/prevention & control , Swine Diseases/virology , Vaccines, Virus-Like Particle/genetics , Vaccines, Virus-Like Particle/immunology , Viral Envelope Proteins/genetics , Viral Envelope Proteins/immunology , Viral Load , Viral Vaccines/genetics , Viral Vaccines/immunology
3.
Rev Med Virol ; 29(1): e2018, 2019 01.
Article in English | MEDLINE | ID: mdl-30411827

ABSTRACT

Emerging porcine pestivirus diseases frequently challenge prevention and control strategies in the swine industry. Over the past decade, a few novel pestiviruses have been identified in pigs. This article focuses on the recently emerging atypical porcine pestivirus (APPV) that potentially threatens global swine herd health security. The virus was first identified in 2016, in the United States and thereafter, accumulated evidence shows that it is currently distributed in three continents. The clinical presentation of APPV-infected pigs is characterized by congenital tremor (CT) type A-II in piglets, while adult pigs may become persistent carriers and shedders. Here, a literature review is conducted to summarize the published findings in the virus genomic biology, transmission, epidemiology, pathogenesis, and diagnosis, which would shed light on acceleration of development of anti-APPV strategies.


Subject(s)
Communicable Diseases, Emerging/veterinary , Pestivirus Infections/veterinary , Pestivirus/classification , Pestivirus/isolation & purification , Swine Diseases/epidemiology , Swine Diseases/virology , Animal Husbandry , Animals , Carrier State/epidemiology , Carrier State/veterinary , Carrier State/virology , Communicable Diseases, Emerging/epidemiology , Communicable Diseases, Emerging/pathology , Communicable Diseases, Emerging/virology , Diagnostic Tests, Routine , Disease Transmission, Infectious , Global Health , Pestivirus/genetics , Pestivirus Infections/epidemiology , Pestivirus Infections/pathology , Pestivirus Infections/virology , Swine , Swine Diseases/pathology , Virus Shedding
4.
J Gen Virol ; 100(1): 84-88, 2019 01.
Article in English | MEDLINE | ID: mdl-30516465

ABSTRACT

Atypical porcine pestivirus (APPV) causes congenital tremor (CT) in piglets and has a wide geographical distribution. In this study, we evaluated APPV prevalence using 165 piglet sera from southwest China. Viral RNA was detectable by qRT-PCR in 43.6 % (17/39, 95 % CI 27.8-60.4 %) of piglets with CT, while viral RNA was not detected in the sera of any healthy piglets. The seven complete APPV genomes were obtained from distinct farms and were 11 269-11 459 nucleotides in length. The genomes of the seven strains shared 82.8-98 % identity with the APPV reference strains. Phylogenetic analysis of the complete genomes as well as E2 and Nrpo sequences revealed that the seven APPVs clustered into two groups: four strains belonged to genogroups A and D and three strains belonged to a novel APPV genotype, tentatively called genogroup E. This study provides important insights into the epidemiological features and genetic diversity of APPV.


Subject(s)
Genome, Viral , Genotype , Pestivirus Infections/veterinary , Pestivirus/classification , Pestivirus/genetics , Swine Diseases/epidemiology , Swine Diseases/virology , Animals , China/epidemiology , Pestivirus/isolation & purification , Pestivirus Infections/epidemiology , Pestivirus Infections/virology , Phylogeny , Prevalence , RNA, Viral/analysis , RNA, Viral/blood , Real-Time Polymerase Chain Reaction , Sequence Homology , Swine , Whole Genome Sequencing
5.
Arch Virol ; 164(10): 2519-2523, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31270607

ABSTRACT

A newly identified atypical porcine pestivirus (APPV) associated with congenital tremors in newborn piglets has been shown to have a worldwide geographic distribution. In view of the function of Erns in pestivirus infection and replication, the viral load and histological distribution of APPV in different tissues of naturally infected piglets were analyzed by quantitative RT-PCR and immunohistochemical detection using Erns as the target. The results showed that the viral copy number was higher in the cerebellum, submandibular lymph nodes, and thymus than in other tissues, indicating that these are important target organs of APPV. The histological distribution of APPV was mainly in the matrix and nerve fiber in nervous tissues, endothelial cells in lymphoid tissues, and epithelial cells in other tissues, suggesting that these cells were target cells of APPV. The results will provide basic data for elucidating the pathogenesis and deepening the understanding of this newly discovered pathogen.


Subject(s)
Animal Structures/virology , Animals, Newborn , Pestivirus Infections/veterinary , Pestivirus/isolation & purification , Swine Diseases/virology , Swine , Viral Load , Animals , Immunohistochemistry , Pestivirus Infections/virology , Real-Time Polymerase Chain Reaction
6.
Virus Genes ; 55(3): 298-303, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30706196

ABSTRACT

Bungowannah virus, which belongs to the genus Pestivirus within the family Flaviviridae, has been associated with myocarditis and a high incidence of stillbirths in pigs. In 2003, the virus was initially detected in a large pig farming complex on two separate sites in New South Wales, Australia. Until now, it has not been detected at other locations. Despite a program of depopulation and disinfection, the virus could be only eradicated from one of the affected farm complexes, the Bungowannah unit, but became endemic on the second complex, the Corowa unit. In the present study, the genetic variability of virus isolates collected between 2003 and 2014 in the endemically infected population has been retrospectively investigated. Phylogenetic analysis carried out based on sequences of the E2 and NS5B coding regions and the full-length open-reading frame revealed that the isolates from the different farm sites are closely related, but that samples collected between 2010 and 2014 at the Corowa farm site clustered in a different branch of the phylogenetic tree. Since 2010, a high-genetic stability of this RNA virus within the Corowa farm complex, probably due to an effective adaptation of the virus to the affected pig population, could be observed.


Subject(s)
Pestivirus Infections/genetics , Pestivirus/genetics , Stillbirth/genetics , Swine Diseases/genetics , Animals , Australia , Disease Outbreaks , Pestivirus/pathogenicity , Pestivirus Infections/veterinary , Pestivirus Infections/virology , Retrospective Studies , Stillbirth/veterinary , Swine , Swine Diseases/virology
7.
BMC Vet Res ; 15(1): 202, 2019 Jun 14.
Article in English | MEDLINE | ID: mdl-31200717

ABSTRACT

BACKGROUND: Bovine viral diarrhea virus (BVDV) infects various ungulates and causes reproductive failure in infected goats. BVDV has been detected among goats in the Republic of Korea, but the route of transmission remains unclear. Here, we aimed to investigate whether BVDV-1b circulating among Korean cattle can be transmitted to Korean native goats (Capra aegagrus hircus) and characterize the outcomes of BVDV infection in these goats. RESULTS: Four goats were inoculated intranasally with the Korean noncytopathic (ncp) BVDV-1b strain. Two goats exhibited clinical signs of illness, including coughing and nasal discharge. Nasal swabs and blood were collected to screen for viral RNA and BVDV antibodies. Using the 5'-untranslated region (UTR), viral RNA was detected in the nasal swabs of two goats (Goat 1 and 3) on 12 day post-inoculation (dpi) and in the blood sample of one goat (Goat 1) on 7 and 19 dpi. Using the N-terminal protease (Npro) region, viral RNA was detected in the blood sample of Goat 1 on 7 and 12 dpi. Antibodies to BVDV were detected in Goats 1 and 3 on 16-21 dpi using enzyme-linked immunosorbent assay. Sequence analysis of the virus from nasal swabs and blood samples, which was detected via RT-PCR, using the 5'-UTR and Npro regions led to the identification of the strain as ncp BVDV-1b and revealed changes in the nucleotide sequence of these goats. CONCLUSIONS: Our results indicate that changes in the nucleotide sequence are associated with the establishment of BVDV infection in Korean native goats; these changes may be owing to a process required for the establishment of infection in a new host reservoir. Broadly, these findings highlight the importance of BVDV surveillance in ungulates other than cattle.


Subject(s)
Diarrhea Virus 1, Bovine Viral/genetics , Goat Diseases/virology , Pestivirus Infections/veterinary , 5' Untranslated Regions , Animals , Antibodies, Viral/blood , Diarrhea Virus 1, Bovine Viral/immunology , Diarrhea Virus 1, Bovine Viral/pathogenicity , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Goat Diseases/transmission , Goats , Nasal Mucosa/virology , Pestivirus Infections/genetics , Pestivirus Infections/virology , RNA, Viral/blood , RNA, Viral/genetics , Republic of Korea , Sequence Analysis, RNA
8.
J Virol ; 91(21)2017 11 01.
Article in English | MEDLINE | ID: mdl-28835495

ABSTRACT

The nonstructural protein NS3 from the Flaviviridae family is a multifunctional protein that contains an N-terminal protease and a C-terminal helicase, playing essential roles in viral polyprotein processing and genome replication. Here we report a full-length crystal structure of the classical swine fever virus (CSFV) NS3 in complex with its NS4A protease cofactor segment (PCS) at a 2.35-Å resolution. The structure reveals a previously unidentified ∼2,200-Å2 intramolecular protease-helicase interface comprising three clusters of interactions, representing a "closed" global conformation related to the NS3-NS4A cis-cleavage event. Although this conformation is incompatible with protease trans-cleavage, it appears to be functionally important and beneficial to the helicase activity, as the mutations designed to perturb this conformation impaired both the helicase activities in vitro and virus production in vivo Our work reveals important features of protease-helicase coordination in pestivirus NS3 and provides a key basis for how different conformational states may explicitly contribute to certain functions of this natural protease-helicase fusion protein.IMPORTANCE Many RNA viruses encode helicases to aid their RNA genome replication and transcription by unwinding structured RNA. Being naturally fused to a protease participating in viral polyprotein processing, the NS3 helicases encoded by the Flaviviridae family viruses are unique. Therefore, how these two enzyme modules coordinate in a single polypeptide is of particular interest. Here we report a previously unidentified conformation of pestivirus NS3 in complex with its NS4A protease cofactor segment (PCS). This conformational state is related to the protease cis-cleavage event and is optimal for the function of helicase. This work provides an important basis to understand how different enzymatic activities of NS3 may be achieved by the coordination between the protease and helicase through different conformational states.


Subject(s)
DNA Helicases/metabolism , Pestivirus/enzymology , RNA Helicases/metabolism , Serine Endopeptidases/metabolism , Viral Nonstructural Proteins/metabolism , Amino Acid Sequence , Animals , Cells, Cultured , Crystallography, X-Ray , DNA Helicases/chemistry , Models, Molecular , Pestivirus Infections/metabolism , Pestivirus Infections/virology , Protein Conformation , RNA Helicases/chemistry , Sequence Homology , Serine Endopeptidases/chemistry , Substrate Specificity , Swine , Viral Nonstructural Proteins/chemistry
9.
Microb Pathog ; 123: 264-268, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30040999

ABSTRACT

Hobi-like viruses (HobiPeV) comprise a novel, recently classified species of bovine pestiviruses, originally identified in commercial fetal bovine serum of Brazilian origin and, subsequently, isolated from diseased animals in several countries. Although frequently isolated from clinical cases, most HobiPeV isolates failed to reproduce overt disease in cattle upon experimental inoculation. Herein, we describe the outcome of experimental infection of four to six months-old seronegative calves with two Brazilian HobiPeV isolates. Calves inoculated intranasally with isolate SV478/07 developed viremia between days 2 and 9 post-inoculation (pi) and shed virus in nasal secretions up to day 11pi. These animals presented hyperthermia (day 7 to 10-11 pi) and lymphopenia from days 4 to 8pi. Clinically, all four calves developed varied degrees of apathy, anorexia, mild to moderate respiratory signs (nasal secretion, hyperemia), ocular discharge and pasty diarrhea in the days following virus inoculation. In contrast, calves inoculated with isolate SV757/15 presented only hyperthermia (days 3 to 10-11 pi) and lymphopenia (days 4-8 pi), without other apparent clinical signs. In these animals, viremia was detected up to day 9 pi and virus shedding in nasal secretions lasted up to day 12-14 pi. Both groups seroconverted to the inoculated viruses, developing virus neutralizing (VN) titers from 320 to 5120 at day 28pi. These results extend previous findings that experimental infections of calves with HobiPeV are predominantly mild, yet they also indicate that field isolates may differ in their ability to cause disease in susceptible animals.


Subject(s)
Bovine Virus Diarrhea-Mucosal Disease/virology , Cattle Diseases/virology , Cattle/virology , Diarrhea Viruses, Bovine Viral/classification , Diarrhea Viruses, Bovine Viral/pathogenicity , Fever/virology , Lymphopenia/virology , Pestivirus Infections/virology , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Body Temperature , Bovine Virus Diarrhea-Mucosal Disease/immunology , Bovine Virus Diarrhea-Mucosal Disease/physiopathology , Brazil , Diarrhea Viruses, Bovine Viral/isolation & purification , Disease Models, Animal , Male , Pestivirus Infections/immunology , Pestivirus Infections/veterinary , Time Factors , Viral Load , Viremia/virology , Virus Shedding
10.
Virol J ; 15(1): 115, 2018 07 28.
Article in English | MEDLINE | ID: mdl-30055639

ABSTRACT

BACKGROUND: Bovine viral diarrhea virus (BVDV) causes significant economic losses worldwide in the cattle industry through decrease in productive performance and immunosuppression of animals in herds. Recent studies conducted by our group showed that mice can be infected with BVDV-1 by the oral route. The purpose of this study was to assess the clinical signs, hematological changes, histopathological lesions in lymphoid tissues, and the distribution of the viral antigen after oral inoculation with a Korean noncytopathic (ncp) BVDV-2 field isolate in mice. METHODS: Mice were orally administered a low or high dose of BVDV-2; blood and tissue samples were collected on days 2, 5, and 9 postinfection (pi). We monitored clinical signs, hematological changes, histopathological lesions, and tissue distribution of a viral antigen by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) and then compared these parameters with those in ncp BVDV-1 infections. RESULTS: None of the infected mice developed any clinical signs of the illness. Significant thrombocytopenia was found in both low- and high-dose-inoculated mice on day 2 pi. Leukopenia was apparent only in low-dose-inoculated mice on day 2 pi, whereas lymphopenia was not observed in any ncp BVDV-2-infected animal. Viral RNA was found in the spleen in of low- and high-dose-inoculated mice by RT-PCR. According to the results of IHC, the viral antigen was consistently detected in lymphocytes of bone marrow and spleen and less frequently in bronchus-associated lymphoid tissue (BALT), mesenteric lymph nodes, and Peyer's patches. Despite the antigen detection in BALT and mesenteric lymph nodes, histopathological lesions were not observed in these tissues. Lympholysis, infiltration by inflammatory cells, and increased numbers of megakaryocytes were seen in Peyer's patches, spleens, and bone marrow, respectively. In contrast to ncp BVDV-1 infection, lympholysis was found in the spleen of ncp BVDV-2-infected mice. These histopathological lesions were more severe in high-dose-inoculated mice than in low-dose-inoculated mice. CONCLUSIONS: Our results provide insight into the pathogenesis of ncp BVDV-2 infection in mice. Collectively, these results highlight significant differences in pathogenesis between ncp BVDV-1 and ncp BVDV-2 infections in a murine model.


Subject(s)
Bone Marrow/pathology , Diarrhea Virus 2, Bovine Viral/physiology , Megakaryocytes/pathology , Megakaryocytes/virology , Pestivirus Infections/pathology , Pestivirus Infections/virology , Animals , Cattle , Disease Models, Animal , Hemorrhagic Syndrome, Bovine/blood , Hemorrhagic Syndrome, Bovine/pathology , Hemorrhagic Syndrome, Bovine/virology , Mice , Pestivirus Infections/blood , Peyer's Patches/pathology , Peyer's Patches/virology , RNA, Viral , Spleen/pathology , Spleen/virology , Viral Load
11.
Virus Genes ; 54(4): 603-607, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29909436

ABSTRACT

Natural Pestivirus H infections in cattle have been reported worldwide; however, only a few cases of Pestivirus H have been described in non-bovine ruminants such as goats. A new Pestivirus H HN1507 strain was isolated from an infected goat in 2015 and the genome sequence was determined. The full-length genome sequence was 12,556 nucleotides. Phylogenetic analysis, based on the complete genome and Npro fragments, revealed that the isolate belonged to Pestivirus H and was closely related to strains from Italy. Two unique amino acid substitutions were found in the C-terminal of the E2 protein. To the best of our knowledge, this is first report determining the complete genome of a Pestivirus H strain from goat.


Subject(s)
Goat Diseases/virology , Pestivirus Infections/veterinary , Pestivirus/classification , Pestivirus/isolation & purification , Animals , China , Cluster Analysis , Genome, Viral , Genotype , Goats , Mutation, Missense , Pestivirus/genetics , Pestivirus Infections/virology , Phylogeny , Sequence Analysis, DNA , Sequence Homology , Viral Envelope Proteins/genetics , Whole Genome Sequencing
13.
J Gen Virol ; 98(8): 2106-2112, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28786787

ABSTRACT

We propose the creation of seven new species in the genus Pestivirus (family Flaviviridae) in addition to the four existing species, and naming species in a host-independent manner using the format Pestivirus X. Only the virus species names would change; virus isolates would still be referred to by their original names. The original species would be re-designated as Pestivirus A (original designation Bovine viral diarrhea virus 1), Pestivirus B (Bovine viral diarrhea virus 2), Pestivirus C (Classical swine fever virus) and Pestivirus D (Border disease virus). The seven new species (and example isolates) would be Pestivirus E (pronghorn pestivirus), Pestivirus F (Bungowannah virus), Pestivirus G (giraffe pestivirus), Pestivirus H (Hobi-like pestivirus), Pestivirus I (Aydin-like pestivirus), Pestivirus J (rat pestivirus) and Pestivirus K (atypical porcine pestivirus). A bat-derived virus and pestiviruses identified from sheep and goat (Tunisian sheep pestiviruses), which lack complete coding region sequences, may represent two additional species.


Subject(s)
Pestivirus Infections/veterinary , Pestivirus/classification , Pestivirus/isolation & purification , Animals , Cattle , Goats , Pestivirus/genetics , Pestivirus/physiology , Pestivirus Infections/virology , Phylogeny , Rats , Sheep , Swine
14.
Arch Virol ; 162(10): 3025-3034, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28669036

ABSTRACT

'HoBi'-like viruses comprise a putative new species within the genus Pestivirus of the family Flaviviridae. 'HoBi'-like viruses have been detected worldwide in batches of fetal calf serum, in surveillance programs for bovine pestiviruses and from animals presenting clinical signs resembling bovine viral diarrhea virus (BVDV)-associated diseases. To date, few complete genome sequences of 'HoBi'-like viruses are available in public databases. Moreover, detailed analyses of such genomes are still scarce. In an attempt to expand data on the genetic diversity and biology of pestiviruses, two genomes of 'HoBi'-like viruses recovered from Brazilian cattle were described and characterized in this study. Analysis of the whole genome and antigenic properties of these two new 'HoBi'-like isolates suggest that these viruses are genetically close to recognized pestiviruses. The present data provide evidence that 'HoBi'-like viruses are members of the genus Pestivirus and should be formally recognized as a novel species.


Subject(s)
Antigens, Viral/genetics , Genomics , Pestivirus/genetics , Amino Acid Sequence , Animals , Cell Line , Dogs , Genome, Viral , Pestivirus Infections/veterinary , Pestivirus Infections/virology , Phylogeny , RNA, Viral/genetics , Species Specificity , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/metabolism , Virus Cultivation
15.
Arch Virol ; 162(11): 3473-3480, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28795249

ABSTRACT

Naïve pregnant cattle exposed to pestiviruses between 40-125 days of gestation can give birth to persistently infected (PI) calves. Clinical presentation and survivability, in PI cattle, is highly variable even with the same pestivirus strain whereas the clinical presentation in acute infections is more uniform with severity of symptoms being primarily a function of virulence of the infecting virus. The aim of this study was to compare thymic depletion, as measured by comparing the area of the thymic cortex to the medulla (corticomedullary ratio), in acute and persistent infections of the same pestivirus isolate. The same general trends were observed with each pestivirus isolate. Thymic depletion was observed in both acutely and persistently infected calves. The average thymic depletion observed in acutely infected calves was greater than that in age matched PI calves. PI calves, regardless of infecting virus, revealed a greater variability in amount of depletion compared to acutely infected calves. A trend was observed between survivability and depletion of the thymus, with PI calves surviving less than 5 weeks having lower corticomedullary ratios and greater depletion. This is the first study to compare PI and acutely infected calves with the same isolates as well as to evaluate PI calves based on survivability. Further, this study identified a quantifiable phenotype associated with potential survivability.


Subject(s)
Diarrhea Virus 1, Bovine Viral , Diarrhea Virus 2, Bovine Viral , Lymphocytes/pathology , Pestivirus Infections/veterinary , Pestivirus/classification , Thymus Gland/cytology , Animals , Cattle , Diarrhea Virus 1, Bovine Viral/pathogenicity , Diarrhea Virus 2, Bovine Viral/pathogenicity , Pestivirus/pathogenicity , Pestivirus Infections/pathology , Pestivirus Infections/virology , Thymus Gland/pathology , Thymus Gland/virology , Virulence
16.
Virus Genes ; 53(2): 233-239, 2017 Apr.
Article in English | MEDLINE | ID: mdl-27866318

ABSTRACT

In this study, we constructed for the first time a full-length cDNA clone of pig-original bovine viral diarrhea virus 2 (BVDV-2) strain SH-28, modified the cDNA clone (pASH28) for mutant pASHΔNpro and derived virus strain vASHΔNpro by deleting the genomic region encoding the Npro polypeptide, and examined significance of protein Npro for antiviral responses in vitro. Data showed that Npro-deletion mutant virus vASHΔNpro led to significant overexpression of oligo adenylate synthetase (OAS), myxovirus-resistant protein 1 (Mx1), and ubiquitin-like protein 15 (ISG15). Data also revealed that overexpression of Npro, but not NS2 and NS3 proteins, resulted in significant down-regulation of OAS, Mx1, and ISG15 production (p ≤ 0.05) in bovine cells as well as porcine cells transfected with Npro recombinant eukaryotic expression plasmids. Npro (but not NS2 and NS3) was also found to inhibit poly(IC) from inducing production of type I interferon (IFN-I). These results indicated that protein Npro may play multiple roles in regulating antiviral response in host cells interfered by pig BVDV-2 strain, and provided useful information to understand better the mechanism of BVDV-2 persistent infection in pigs.


Subject(s)
Diarrhea Virus 2, Bovine Viral/genetics , Myxovirus Resistance Proteins/genetics , Pestivirus Infections/genetics , Viral Nonstructural Proteins/genetics , Animals , Cattle , Cell Line , Diarrhea Virus 2, Bovine Viral/pathogenicity , Gene Expression Regulation, Viral , Myxovirus Resistance Proteins/biosynthesis , Pestivirus Infections/virology , Swine/virology , Ubiquitins/biosynthesis , Ubiquitins/genetics , Viral Nonstructural Proteins/biosynthesis
17.
Trop Anim Health Prod ; 49(6): 1149-1156, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28504301

ABSTRACT

Despite reports of BVDV infection in several domestic and wild ruminants, no information exists for mithun (Bos frontalis) species. Hence, this study was undertaken to determine prevalence of BVDV infection in mithuns, which contribute significantly to local economy in the North Eastern region of India. Blood and serum samples were collected between 2013 and 2016 from mithuns (n = 466) belonging to the states of Nagaland, Mizoram, and Arunachal Pradesh. Serum samples were tested for BVDV antibodies by a commercial ELISA and leukocytes were tested for BVDV by real-time RT-PCR. The overall true seroprevalence rate was 13.1% (95% confidence interval, CI: 6.9-17.8%) with higher prevalence in mithuns reared under semi-intensive system (27.5%) than in free-ranging mithuns (7.6%). Among the three states, seroprevalence (16.2%) was highest in Nagaland, while prevalence rates varied markedly among geographical locations. Age-wise data showed highest seroprevalence rate in >6-year-old animals (20.6%) than 2-6 years old (16.9%), 6 months-2 years old (8.5%), and <6-month-old animals (11.3%). The seroprevalence was higher in males (20.9%) than in females (12.1%). Among the four mithun strains, higher prevalence was evident in Manipur (30.3%) than Arunachal (21.3%), Nagaland (11.7%), and Mizoram strain (10.2%). However, no BVDV genomic RNA could be detected. The results provide first serological evidence of BVDV infection in mithun species and extend the knowledge on BVDV host range. The baseline data will help further investigations on epidemiology of BVD in mithun and its impact on mithun production.


Subject(s)
Animal Husbandry , Diarrhea Viruses, Bovine Viral/isolation & purification , Pestivirus Infections/veterinary , Ruminants , Animals , Female , India/epidemiology , Male , Pestivirus Infections/epidemiology , Pestivirus Infections/virology , Prevalence , Seroepidemiologic Studies
18.
Arch Virol ; 161(9): 2527-35, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27376375

ABSTRACT

Previously, our study showed that oral inoculation of mice with cytopathic (cp) bovine viral diarrhea virus (BVDV) led to lymphocyte depletion and increased numbers of megakaryocytes in the spleen as well as thrombocytopenia and lymphopenia. In the present study, to investigate the possible differences in the detection of viral antigen, histopathological lesions, and hematologic changes between non-cytopathic (ncp) BVDV1 and cp BVDV1, mice were orally administered low and high doses of ncp BVDV1 and were necropsied at days 0, 2, 5, and 9 postinfection (pi). None of the ncp BVDV1-infected mice exhibited clinical signs of illness, unlike those infected with cp BVDV1. Statistically significant thrombocytopenia was observed during ncp BVDV1 infection, and lymphopenia was found only in mice infected with a high dose at day 9 pi. Interestingly, ncp BVDV1 infection increased the numbers of basophils, eosinophils, neutrophils, and monocytes in some infected mice. Viral antigen was detected in the lymphocytes of the spleen, mesenteric lymph nodes, Peyer's patches, and bone marrow by immunohistochemistry. Lymphoid depletion was evident in the mesenteric lymph nodes of mice infected with a high dose and also found in the Peyer's patches of some infected mice. Infiltration of inflammatory cells, including neutrophils and monocytes, and an increased number of megakaryocytes were seen in the spleen. These results suggest that the distribution of viral antigens is not associated with the presence of histopathological lesions. Inflammatory cell infiltration was observed in the spleens as a result of viral replication and may be attributable to the host reaction to ncp BVDV1 infection. Together, these findings support the possibility that mice can be used as an animal model for BVDV infection.


Subject(s)
Diarrhea Virus 1, Bovine Viral/pathogenicity , Leukocytes/physiology , Pestivirus Infections/virology , Spleen/cytology , Animals , Mice , Mice, Inbred BALB C , Pestivirus Infections/pathology , Specific Pathogen-Free Organisms , Spleen/virology
19.
Arch Virol ; 161(2): 395-403, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26586332

ABSTRACT

Bovine viral diarrhea virus (BVDV) is an economically important pathogen that causes development of mild to severe clinical signs in wild and domesticated ruminants. We previously showed that mice could be infected by BVDV. In the present study, we infected mice intraperitoneally with non-cytopathic (ncp) BVDV1 or ncp BVDV2, harvested the blood and organs of the infected mice at days 4, 7, 10 and 14 postinfection (pi), and performed immunohistochemical analyses to confirm BVDV infection. Viral antigens were detected in the spleens of all infected mice from days 4 through 14 and were also found in the mesenteric lymph nodes, gut-associated lymphoid tissue (GALT), heart, kidney, intestine, and bronchus-associated lymphoid tissue (BALT) of some infected mice. In ncp BVDV2-infected mice, flow cytometric analysis revealed markedly fewer CD4(+) and CD8(+) T lymphocytes and lower expression of costimulatory molecules CD80 (B7-1) and CD86 (B7-2) and major histocompatibility complex (MHC) class II (I-A/I-E) than those in ncp BVDV1-infected mice. Production of the cytokines interleukin (IL)-6 and monocyte chemotactic protein (MCP)-1 was higher in the plasma of ncp BVDV2-infected mice than that in that of ncp BVDV1-infected mice. Our results demonstrate that ncp BVDV1 and ncp BVDV2 interact differently with the host innate immune response in vivo. These findings highlight an important distinction between ncp BVDV1 and ncp BVDV2 and suggest that ncp BVDV2 impairs the host's ability to control the infection and enhances virus dissemination.


Subject(s)
Diarrhea Virus 2, Bovine Viral/immunology , Diarrhea Virus 2, Bovine Viral/pathogenicity , Pestivirus Infections/pathology , Pestivirus Infections/virology , Animal Structures/virology , Animals , Antigens, Viral/analysis , Disease Models, Animal , Flow Cytometry , Immune Tolerance , Immunohistochemistry , Injections, Intraperitoneal , Mice , Pestivirus Infections/immunology , T-Lymphocyte Subsets/immunology
20.
BMC Vet Res ; 12(1): 181, 2016 Sep 05.
Article in English | MEDLINE | ID: mdl-27596263

ABSTRACT

BACKGROUND: Bovine viral diarrhea virus (BVDV) is a pathogen of domestic and wildlife animals worldwide and is associated with several diseases. In China, there are many reports about genotyping of BVDV strains originated from cattle and pigs, and some of them focused on the geographical distributions of BVDV. Currently, the goat industry in Jiangsu province of China is under going a rapid expansion. Most of these goat farms are backyard enterprises and in close proximity to pig and cattle farms. However, there was very limited information about BVDV infections in goats. The objective of this study was to assess the frequency of BVDV infections of goats, the relationship of these infections to clinical signs and determine what BVDV genotypes are circulating in Jiangsu province. RESULTS: From 236 goat sera collected from six regions in Jiangsu province between 2011 and 2013, BVDV-1 was identified in 29 samples from the five regions by RT-PCR. The BVDV-1 infections occurred with/without clinical signs. Eight different BVDV-1 strains were identified from these positive samples based on the 5'-untranslated region (5'-UTR) sequences, and further clustered into four BVDV-1 subtypes on the phylogenetic analysis. Three were BVDV-1b, two BVDV-1m, two BVDV-1o, and one BVDV-1p, respectively. CONCLUSIONS: To our knowledge, this is the first report to investigate the occurrence of BVDV and the genotypes of BVDV infecting goats in China. The results indicated that BVDV-1 infections were indeed present and the viruses were with genetic variations in Chinese goat herds. The information would be very useful for prevention and control of BVDV-1 infections in China.


Subject(s)
Diarrhea Virus 1, Bovine Viral/genetics , Diarrhea Virus 1, Bovine Viral/isolation & purification , Goat Diseases/virology , Molecular Epidemiology , Pestivirus Infections/veterinary , Animals , China/epidemiology , Goat Diseases/epidemiology , Goats , Pestivirus Infections/epidemiology , Pestivirus Infections/virology , Phylogeny
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