The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Joaquim Segales - One of the best experts on this subject based on the ideXlab platform.
-
best practice and future challenges for vaccination against Porcine Circovirus type 2
Expert Review of Vaccines, 2015Co-Authors: Joaquim SegalesAbstract:Porcine Circovirus type 2 (PCV2)-systemic disease (SD) (initially named as postweaning multisystemic wasting syndrome) was discovered as an occasional disease affecting postweaning pigs in North-America by mid-1990s. Soon afterward, it was noticed as a devastating disease worldwide. Such scenario prompted to develop vaccine prototypes that worked fairly well under experimental conditions. In spite of the multifactorial nature of the PCV2-SD, the first commercialized vaccines containing inactivated or chimeric PCV2 viruses or PCV2 Cap protein represented by far the best system to control the disease under farm conditions. Moreover, vaccination of non-clinically affected pigs demonstrated a significant improvement of average daily weight gain and, in consequence, the economic importance of the PCV2-subclinical infection. In the present review, a comprehensive overview on PCV2 vaccines and best practices on PCV2 vaccination strategies are presented and discussed.
-
Porcine Circovirus type 2 pcv2 infections clinical signs pathology and laboratory diagnosis
Virus Research, 2012Co-Authors: Joaquim SegalesAbstract:Clinical signs and pathological features are still the corner-stones to suspect and diagnose overt disease associated with PCV2 infection. The clinico-pathological scope of this viral infection has been expanded over time. From the initial description of postweaning multisystemic wasting syndrome, some enteric, respiratory and reproductive disorders have been subsequently linked with PCV2. Porcine dermatitis and nephropathy syndrome, an immunocomplex disease, has also been associated with infection by this virus. All together, these conditions have been grouped under the name of Porcine Circovirus diseases (PCVD) or Porcine Circovirus associated diseases (PCVAD). The precise mechanisms by which a PCV2 infected pig develops a PCV2 subclinical infection or a clinical PCVD/PCVAD are still to be fully elucidated, but inferences based upon clinical, gross and histologic findings from field cases of disease have been useful to suggest the pathogenesis of this viral infection. The objective of the present review is to update the current knowledge on the clinical and pathological scope of PCV2 infections, as well as on their diagnosis. Moreover, a proposal on a unified PCVD/PCVAD terminology and clearly defined diagnostic criteria for these conditions are also given.
-
recent advances in the epidemiology diagnosis and control of diseases caused by Porcine Circovirus type 2
Veterinary Journal, 2011Co-Authors: Llorenc Grauroma, Lorenzo Fraile, Joaquim SegalesAbstract:Post-weaning multisystemic wasting syndrome (PMWS) emerged as a significant disease affecting pig production in the 1990s although the causal agent, Porcine Circovirus type 2 (PCV2), and the disease itself, had existed in swine for many years prior to this. The important multifactorial 'triggers' of PMWS include the immune and infection status of the sow, the timing of PCV2 infection, variations in the virulence of PCV2, co-infections, immune modulation as well as host genetics and management factors. In terms of diagnosis, histopathological examination and the detection of PCV2 within lymphoid tissue remains the 'gold standard' as quantitative PCR techniques are currently not specific or sensitive enough. The recent commercial availability of PCV2 vaccines provides an excellent tool for reducing the impact of PMWS and other Porcine Circovirus-related diseases. This review assesses recent advances in the epidemiology, diagnosis and control of PMWS.
-
Porcine Circovirus diseases
Animal Health Research Reviews, 2005Co-Authors: Joaquim Segales, G. M. Allan, M DomingoAbstract:Porcine Circovirus type 2 (PCV2) is a member of the family Circoviridae, a recently established virus family composed of small, non-enveloped viruses, with a circular, single-stranded DNA genome. PCV2, which is found all over the world in the domestic pig and probably the wild boar, has been recently associated with a number of disease syndromes, which have been collectively named Porcine Circovirus diseases (PCVD). Postweaning multisystemic wasting syndrome (PMWS), Porcine dermatitis and nephropathy syndrome (PDNS) and reproductive disorders are the most relevant ones. Among them, only PMWS is considered to have a severe impact on domestic swine production. PMWS mainly affects nursery and/or fattening pigs; wasting is considered the most representative clinical sign in this disease. Diagnosis of this disease is confirmed by histopathological examination of lymphoid tissues and detection of a moderate to high amount of PCV2 in damaged tissues. Since PMWS is considered a multifactorial disease in which other factors in addition to PCV2 are needed in most cases to trigger the clinical disease, effective control measures have focused on the understanding of the co-factors involved in individual farms and the control or elimination of these triggers. PDNS, an immuno-complex disease characterized by fibrino-necrotizing glomerulonephritis and systemic necrotizing vasculitis, has been linked to PCV2, but a definitive proof of this association is still lacking. PCV2-associated reproductive disease seems to occur very sporadically under field conditions, but it has been characterized by late-term abortions and stillbirths, extensive fibrosing and/or necrotizing myocarditis in fetuses and the presence of moderate to high amounts of PCV2 in these lesions. Taking into account that scientific information on PCV2 and its associated diseases has been markedly expanded in the last 8 years, the objective of this review is to summarize the current state of knowledge of the most relevant aspects of PCV2 biology and PCVD.
-
epidemiological study on Porcine Circovirus type 2 pcv2 infection in the european wild boar sus scrofa
Veterinary Research, 2004Co-Authors: Joaquin Vicente, M Balasch, Joan Planaduran, Ursula Höfle, M Domingo, Joaquim Segales, Christian GortázarAbstract:Porcine Circovirus type 2 (PCV2) is considered as the causative agent of postweaning multisystemic wasting syndrome (PMWS) in domestic pigs, where the virus is ubiquitous as evidenced by serological surveys. We present the results of the first nationwide sero-survey on the presence of PCV2 antibodies in European wild boars, and report the first PMWS case in a wild boar from Spain. Sera from 656 hunter harvested wild boars from 45 different geographical sites and 22 additional imported animals were analysed by means of an immunoperoxidase monolayer assay (IPMA). We also examined the tissues from 55 healthy and one diseased wild boars for the presence of PCV2 nucleic acid and PMWS lesions by in situ hybridisation and histopathology, respectively. Additionally, abundance estimates of wild boars and field interviews were carried out on 30 sampling sites. The prevalence of medium to high PCV2 serological titres among the examined wild boars was 47.89 ± 1.9%. Seropositive wild boars appeared in all but one of the geographical regions analysed. Seroprevalence and titre of PCV2 antibodies were closely related to the management of the wild boar populations. Wild boars from intensively managed, farm-like populations had higher prevalence than wild boars living in more natural situations. The effect of wild boar abundance and management on PCV2 antibody prevalence was further evidenced by the high correlation existing between the relative abundance estimates of animals and the percentage of wild boars with medium to high levels of PCV2 antibodies. PCV2 nucleic acid was detected in the tissues of three wild boars. One of these was diagnosed as PMWS. The results, in addition to information on piglet mortalities, suggest a potential role of PMWS in piglet mortality in intensively managed wild boar populations. European wild boar / Porcine Circovirus type 2 / epidemiology / postweaning multisystemic wasting syndrome
Mariano Domingo - One of the best experts on this subject based on the ideXlab platform.
-
Pathological findings associated with naturally acquired Porcine Circovirus type 2 associated disease.
Veterinary Microbiology, 2004Co-Authors: Joaquim Segales, C. Rosell, Mariano DomingoAbstract:Porcine Circovirus type 2 (PCV2) is a novel virus of the Circoviridae family which is considered the cause of postweaning multisystemic wasting syndrome (PMWS). PCV2 has also been associated to a number of pathological conditions of pigs, including Porcine dermatitis and nephropathy syndrome, reproductive failure, Porcine respiratory disease complex, proliferative and necrotising pneumonia and congenital tremor type AII. Pathological studies have been used to describe and characterise PMWS and these emerging conditions associated with PCV2. The objective of this review is to concentrate on the gross, microscopic and ultrastructural pathology associated with natural cases of PCV2 associated disease, along with some speculations on the pathogenesis of naturally occurring PMWS.
-
detection of Porcine Circovirus types 1 and 2 in serum and tissue samples of pigs with and without postweaning multisystemic wasting syndrome
Journal of Clinical Microbiology, 2002Co-Authors: Maria Calsamiglia, Joaquim Segales, C. Rosell, Mariano Domingo, Josefina QuintanaAbstract:Presence of Porcine Circovirus type 1 (PCV1) and PCV2 was studied in sera and superficial inguinal lymph nodes from postweaning multisystemic wasting syndrome (PMWS)-affected and non-PMWS-affected pigs by using in situ hybridization and PCR. PCV1 and PCV2 were found in less than 3% and more than 50% of the samples, respectively. The most sensitive technique and site was PCR in superficial inguinal lymph nodes, but in situ hybridization correlated better with presence of characteristic lesions.
Annette Mankertz - One of the best experts on this subject based on the ideXlab platform.
-
interaction of the replication proteins and the capsid protein of Porcine Circovirus type 1 and 2 with host proteins
Virology, 2009Co-Authors: Tim Finsterbusch, Tobias Steinfeldt, Kai Doberstein, Claudia Rodner, Annette MankertzAbstract:Porcine Circovirus type 2 (PCV2) is an important pathogen in swine, whereas Porcine Circovirus type 1 (PCV1) is apathogenic. To analyze the interactions between PCV and its host, we have used a yeast two-hybrid assay to identify cellular proteins interacting with Cap and Rep proteins of both PCV genotypes. Six cellular proteins were found to interact with Cap (MKRN1, gC1qR, Par-4, NAP1, NPM1 and Hsp40) and three with Rep (ZNF265, TDG and VG5Q). These interactions were confirmed by co-immunoprecipitation. Investigation of the localisation of the proteins by immunofluorescence revealed in some cases only limited spatial overlapping with Cap, while in others a clear co-localisation and prominent protein redistribution was observed. The nine cellular proteins are associated with distinct aspects of viral lifecycle and our data is likely to support future research in the field of PCV2 pathogenesis.
-
infection studies on human cell lines with Porcine Circovirus type 1 and Porcine Circovirus type 2
Xenotransplantation, 2004Co-Authors: Kim Hattermann, Claudia Roedner, Cornelia Schmitt, Tim Finsterbusch, Tobias Steinfeldt, Annette MankertzAbstract:: Background: The lack of human donor organs in allotransplantation has led to a proposal for the use of Porcine tissues and organs as alternative therapeutic material for humans. Besides immunological problems like graft rejection, one of the major concerns is the transmission of Porcine microorganisms as viruses, bacteria and fungi to a human recipient. Methods: Human cell lines have been infected with Porcine Circovirus type 1 (PCV1) and Porcine Circovirus type 2 (PCV2) to investigate whether PCV can infect and replicate in human epithelial cells and lymphocytes. Infection of PCV1 was observed with 293, Hela and Chang liver cells, infection with PCV2 only in Rd cells. In addition, religated viral DNA of PCV1 and PCV2 has been used to transfect adherent human cell lines. Results: PCV1 persisted in most cell lines without causing any visible changes, while PCV2-transfected cells showed a cytopathogenic effect. Presence of PCV DNA was detected in cells and supernatant by PCR, expression of viral proteins by an indirect immune fluorescence assay. A replication assay showed that the replication of PCV DNA was initiated at the origin of replication. When virus-free cells were inoculated with the supernatant of PCV-infected human cells, the infection was not passed. Conclusion: Although PCV gene expression and replication took place in human cells, the infection is non-productive. Alteration of protein localization suggests that protein targeting may be disturbed in human cells.
-
analysis of transcription of Porcine Circovirus type 1
Journal of General Virology, 2002Co-Authors: Annette Mankertz, Bernd HillenbrandAbstract:Porcine Circovirus type 1 (PCV1) contains two major open reading frames encoding the replication initiator proteins, Rep and Rep′, and the structural protein, Cap. The promoters of these two genes (P cap and P rep ) have been mapped. P cap is located within the rep open reading frame (nt 1328–1252). P rep has been mapped to the intergenic region immediately upstream of the rep gene (nt 640–796) and overlaps the origin of replication of PCV1. Although binding of both rep gene products to a fragment containing P rep and the overlapping origin of replication has been reported, only the full-length Rep protein repressed P rep , while the spliced isoform Rep′ did not. P rep repression is mediated by binding of the Rep protein to the two inner hexamers, H1 and H2, located in the origin of PCV1, whereas binding of Rep to hexamers H3 and H4 was not necessary. Use of Rep mutants indicated that the conserved rolling-circle replication domain II as well as the P loop are essential for repression of P rep . In contrast to P rep , transcription of P cap was not influenced by viral proteins. Additionally, the ratio of the rep and rep′ transcripts was analysed. Twelve hours after transfection of PK15 cells with an infectious clone of PCV1, similar amounts of both transcripts were detected, but later the amount of the two transcripts varied, indicating a balanced expression of the two rep transcripts.
-
identification of a protein essential for replication of Porcine Circovirus
Journal of General Virology, 1998Co-Authors: Annette Mankertz, Joachim Mankertz, Katarina Wolf, H J BuhkAbstract:The largest open reading frame of Porcine Circovirus (ORF 4) encodes a protein of 312 amino acids. The predicted gene product of ORF 4 shows similarities to Rep proteins of other plant Circoviruses and geminiviruses. Three motifs have been identified that are characteristic for proteins involved in rolling circle replication and the consensus sequence for a putative dNTP-binding box (GKS) has been found. In this paper, experimental evidence is presented which indicates that ORF 4 encodes the replication protein of Porcine Circovirus. After cloning of the ORF 4 gene product, it was supplied in trans in a transient replication assay. The ORF 4 gene product promoted the replication of plasmid pOP11, which carries the origin of DNA replication of Porcine Circovirus. Since pOP11 itself is unable to replicate in virus-free Porcine kidney cells, the ORF 4 gene product must be essential for replication of Porcine Circovirus.
-
Mapping and characterization of the origin of DNA replication of Porcine Circovirus.
Journal of virology, 1997Co-Authors: Annette Mankertz, F Persson, Joachim Mankertz, G Blaess, H J BuhkAbstract:The origin of DNA replication of Porcine Circovirus (PCV) was mapped to a 111-bp fragment. On top of a hairpin, a nonanucleotide (TAGTATTAC) homologous to nonanucleotides of other viruses was identified. Mutation of this element abolishes replication. PCV may be related to a virus family characterized by single-stranded circular DNA genomes, rolling-circle replication, and homology of their rep proteins.
Xiangjin Meng - One of the best experts on this subject based on the ideXlab platform.
-
Porcine Circovirus type 2 pcv2 pathogenesis and interaction with the immune system
Annual Review of Animal Biosciences, 2013Co-Authors: Xiangjin MengAbstract:Porcine Circovirus type 2 (PCV2) is the primary causative agent of Porcine Circovirus–associated disease (PCVAD). The virus preferentially targets the lymphoid tissues, which leads to lymphoid depletion and immunosuppression in pigs. The disease is exacerbated by immunostimulation or concurrent infections with other pathogens. PCV2 resides in certain immune cells, such as macrophage and dendritic cells, and modulates their functions. Upregulation of IL-10 and proinflammatory cytokines in infected pigs may contribute to pathogenesis. Pig genetics influence host susceptibility to PCV2, but the viral genetic determinants for virulence remain unknown. PCV2 DNA and proteins interact with various cellular genes that control immune responses to regulate virus replication and pathogenesis. Both neutralizing antibodies and cell-mediated immunity are important immunological correlates of protection. Despite the availability of effective vaccines, variant strains of PCV2 continue to emerge. Although tremendous progr...
-
efficacy and future prospects of commercially available and experimental vaccines against Porcine Circovirus type 2 pcv2
Virus Research, 2012Co-Authors: Nathan M Beach, Xiangjin MengAbstract:Porcine Circovirus type 2 (PCV2) is the causative agent of an economically significant collection of disease syndromes in pigs, now known as Porcine Circovirus associated diseases (PCVADs) in the United States or Porcine Circovirus diseases (PCVDs) in Europe. Inactivated and subunit vaccines based on PCV2a genotype are commercially available and have been shown to be effective at decreasing mortality and increasing growth parameters in commercial swine herds. Since 2003, there has been a drastic global shift in the predominant prevalence of PCV2b genotype in swine populations, concurrently in most but not all cases with increased severity of clinical disease. Although the current commercial vaccines based on PCV2a do confer cross-protection against PCV2b, novel experimental vaccines based on PCV2b genotype such as modified live-attenuated vaccines are being developed and may provide a superior protection and reduce vaccine costs. In this review, we discuss the current understanding of the impact of PCV2 infection on the host immune response, review the efficacy of the currently available commercial PCV2 vaccines in experimental and field conditions, and provide insight into novel experimental approaches that are useful in the development of next generation vaccines against PCV2.
-
replacement of the replication factors of Porcine Circovirus pcv type 2 with those of pcv type 1 greatly enhances viral replication in vitro
Journal of Virology, 2010Co-Authors: Nathan M Beach, Nicole M Juhan, Laura Cordoba, Xiangjin MengAbstract:Porcine Circovirus type 1 (PCV1), originally isolated as a contaminant of PK-15 cells, is nonpathogenic, whereas Porcine Circovirus type 2 (PCV2) causes an economically important disease in pigs. To determine the factors affecting virus replication, we constructed chimeric viruses by swapping open reading frame 1 (ORF1) (rep) or the origin of replication (Ori) between PCV1 and PCV2 and compared the replication efficiencies of the chimeric viruses in PK-15 cells. The results showed that the replication factors of PCV1 and PCV2 are fully exchangeable and, most importantly, that both the Ori and rep of PCV1 enhance the virus replication efficiencies of the chimeric viruses with the PCV2 backbone.
-
Porcine Circovirus Type 2 and Porcine Circovirus-Associated Disease
Journal of Veterinary Internal Medicine, 2009Co-Authors: J. Gillespie, Tanja Opriessnig, Xiangjin Meng, K. Pelzer, Virginia Buechner-maxwellAbstract:Porcine Circovirus type 2 (PCV2) belongs to the viral family Circoviridae and to the genus Circovirus. Circoviruses are small, single-stranded nonenveloped DNA viruses that have an unsegmented circular genome. PCV2 is the primary causative agent of several syndromes collectively known as Porcine Circovirus-associated disease (PCVAD). Many of the syndromes associated with PCVAD are a result of coinfection with PCV2 virus and other agents such as Mycoplasma and Porcine reproductive and respiratory syndrome virus. PCV2 infection is present in every major swine-producing country in the world, and the number of identified cases of PCVAD is rapidly increasing. In the United States, the disease has cost producers an average of 3-4 dollars per pig with peak losses ranging up to 20 dollars per pig. The importance of this disease has stimulated investigations aimed at identifying risk factors associated with infection and minimizing these risks through modified management practices and development of vaccination strategies. This paper provides an overview of current knowledge relating to PCV2 and PCVAD with an emphasis on information relevant to the swine veterinarian.
Tanja Opriessnig - One of the best experts on this subject based on the ideXlab platform.
-
Novel Circovirus species identified in farmed pigs designated as Porcine Circovirus 4, Hunan province, China.
Transboundary and emerging diseases, 2019Co-Authors: Hui-hui Zhang, Tian-ning Liu, Ji‐yong Zhou, Chao-ting Xiao, Tanja OpriessnigAbstract:In pigs, three Circovirus species within the genus Circovirus have been identified so far, including the non-pathogenic Porcine Circovirus 1 (PCV1), the pathogenic Porcine Circovirus 2 (PCV2) and the recently identified Porcine Circovirus 3 (PCV3). In April 2019, a new Circovirus with a distinct relationship to other Circoviruses was identified in several pigs with severe clinical disease in Hunan province, China. The size of the viral genome, tentatively designated as Porcine Circovirus type 4 (PCV4), is 1,770 nucleotides (nt). PCV4 shows the highest genomic identity to mink Circovirus (66.9%) and has identities of 43.2%-51.5% to the other PCV genomes. Two major genes, a replicase (Rep) gene spanning 891 nt and a capsid (Cap) gene spanning 687 nt, were predicted. Furthermore, a TaqMan® real-time polymerase chain reaction (PCR) targeting the replicase gene was developed to investigate the prevalence of PCV4 in 187 clinical samples from Hunan province, China. The results revealed an overall PCV4 prevalence of 12.8%, with the highest positive rates in nasal swabs (28.5%, 6/21) followed by serum samples (13.4%, 11/82). The clinical significance and pathogenesis of this virus needs further investigation.
-
complete genome sequence of a novel Porcine Circovirus type 2b variant present in cases of vaccine failures in the united states
Journal of Virology, 2012Co-Authors: Chao-ting Xiao, Patrick G Halbur, Tanja OpriessnigAbstract:Two genomes of a new Porcine Circovirus type 2 (PCV2) strain associated with cases of perceived failure of PCV2 vaccination were sequenced and analyzed. Based on the genome, this is the first report of this mutant of PCV2b in the United States. The genomic knowledge of this mutant PCV2b will improve understanding of the epidemiology of PCV and potentially inform the development of new and more effective vaccines for PCV2.
-
concurrent infections are important for expression of Porcine Circovirus associated disease
Virus Research, 2012Co-Authors: Tanja Opriessnig, Patrick G HalburAbstract:Porcine Circovirus type 2 (PCV2) is the essential component of Porcine Circovirus disease (PCVD) as the disease syndrome is referred to in Europe and Porcine Circovirus associated disease (PCVAD) as it is referred to in North America. Singular PCV2 infection rarely results in clinical disease; however, PCVAD is often accelerated in onset, enhanced in severity and prolonged in duration by concurrent viral or bacterial infections. Due to its effect on the immune system, PCV2 has also been shown to enhance protozoal, metazoal, and fungal infections. Several retrospective or cross-sectional studies have investigated the presence and prevalence of various infectious agents associated with PCVAD under field conditions. Experimental models confirm that PCV2 replication and associated lesions can be enhanced by concurrent infection with other viruses or bacteria. The exact mechanisms by which concurrent pathogens upregulate PCV2 are unknown. Co-infections may promote PCV2 infection by increasing immune host cell replication and accumulation in tissues thereby enhancing targets for PCV2 replication. It has also been proposed that co-infections interfere with PCV2 clearance by alteration of cytokine production and profiles. The outcome of differences in timing of co-infections in PCV2-infected pigs is also likely very important and is an area where more research is needed. Given the current knowledge base, it is important that veterinarians do a thorough diagnostic investigation on herds where PCVAD is a recurrent problem in order to implement the most appropriate and cost effective intervention strategies.
-
Porcine Circovirus Type 2 and Porcine Circovirus-Associated Disease
Journal of Veterinary Internal Medicine, 2009Co-Authors: J. Gillespie, Tanja Opriessnig, Xiangjin Meng, K. Pelzer, Virginia Buechner-maxwellAbstract:Porcine Circovirus type 2 (PCV2) belongs to the viral family Circoviridae and to the genus Circovirus. Circoviruses are small, single-stranded nonenveloped DNA viruses that have an unsegmented circular genome. PCV2 is the primary causative agent of several syndromes collectively known as Porcine Circovirus-associated disease (PCVAD). Many of the syndromes associated with PCVAD are a result of coinfection with PCV2 virus and other agents such as Mycoplasma and Porcine reproductive and respiratory syndrome virus. PCV2 infection is present in every major swine-producing country in the world, and the number of identified cases of PCVAD is rapidly increasing. In the United States, the disease has cost producers an average of 3-4 dollars per pig with peak losses ranging up to 20 dollars per pig. The importance of this disease has stimulated investigations aimed at identifying risk factors associated with infection and minimizing these risks through modified management practices and development of vaccination strategies. This paper provides an overview of current knowledge relating to PCV2 and PCVAD with an emphasis on information relevant to the swine veterinarian.
