RESUMO
Porcine circovirus type 2 (PCV2) causes postweaning multisystemic wasting syndrome in piglets. Differences in the infectivity and horizontal transmissibility of different isolates of PCV2a, PCV2b, and PCV2d in pigs were evaluated by HE and IHC staining, PCR, virus titration, and IPMA to determine their clinical symptoms, pathological changes, levels of virus and antibody, and cohabitation infectivity. In the cohabitation infection experiment, weak viremia and low levels of antibodies were detected in the pigs challenged with PCV2a-CL, whereas no viremia or antibodies were detected in the corresponding cohabiting pigs. Furthermore, no PCV2 was isolated from any organ of pigs that were challenged with PCV2a-CL, as well as from those of their cohabiting pigs. In contrast, persistent viremia and pathological changes, including swollen inguinal lymph nodes, were detected in both the challenged and cohabiting pigs after PCV2b-BY or PCV2d-LNHC infection. Alive PCV2 was detected in the tonsils, inguinal lymph nodes, spleen, and kidneys of the experimental pigs by virus titration, and the highest viral titer was detected in the tonsils, followed by the inguinal lymph nodes. In a comparative analysis of the challenged and cohabiting pigs, a 1-week delay in viremia and specific antibodies was observed in the cohabiting pigs. Moreover, the number of viruses isolated from the tonsils and inguinal lymph nodes of the pigs cohabiting with PCV2d-LNHC-challenged pigs was significantly greater than those in the pigs that were directly challenged with PCV2d-LNHC in cohabitation infection experiment (P<0.05). Together, these results indicated that the infectivity and horizontal transmissibility of the strains PCV2b-BY and PCV2d-LNHC were much greater than those of the strain PCV2a-CL and provided some insights into PCV2 pathogenicity.
Assuntos
Anticorpos Antivirais , Infecções por Circoviridae , Circovirus , Animais , Circovirus/patogenicidade , Circovirus/classificação , Circovirus/isolamento & purificação , Suínos , Infecções por Circoviridae/virologia , Infecções por Circoviridae/veterinária , Infecções por Circoviridae/transmissão , Anticorpos Antivirais/sangue , Viremia/transmissão , Viremia/virologia , Viremia/veterinária , Doenças dos Suínos/virologia , Doenças dos Suínos/transmissão , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/transmissão , Carga ViralRESUMO
Porcine circovirus type 3 (PCV3) has become an important pathogen in the global swine industry and poses a threat to pig health, but its pathogenic mechanism remains unknown. In this study, we constructed an innovative, linear infectious clone of PCV3 for rescuing the virus, and explored the transcriptome of infected cells to gain insights into its pathogenic mechanisms. Subsequently, an in vivo experiment was conducted to evaluate the pathogenicity of the rescued virus in pig. PCV3 nucleic acid was distributed across various organs, indicating systemic circulation via the bloodstream and viremia. Immunohistochemical staining also revealed a significant presence of PCV3 antigens in the spleen, lungs, and lymph nodes, indicating that PCV3 had tropism for these organs. Transcriptome analysis of infected ST cells revealed differential expression of genes associated with apoptosis, immune responses, and cellular metabolism. Notably, upregulation of genes related to the hypoxia-inducible factor-1 pathway, glycolysis, and the AGE/RAGE pathway suggests activation of inflammatory responses, ultimately leading to onset of disease. These findings have expanded our understanding of PCV3 pathogenesis, and the interplay between PCV3 and host factors.
Assuntos
Infecções por Circoviridae , Circovirus , Perfilação da Expressão Gênica , Doenças dos Suínos , Animais , Suínos , Circovirus/genética , Circovirus/patogenicidade , Circovirus/fisiologia , Infecções por Circoviridae/virologia , Infecções por Circoviridae/veterinária , Doenças dos Suínos/virologia , Transcriptoma , Linhagem Celular , Apoptose/genética , Pulmão/virologia , Pulmão/patologiaRESUMO
Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus (PCVs) are two major viruses that affect pigs. Coinfections between PRRSV and PCV2 are frequently reported in most outbreaks, with clinical presentations involving dyspnea, fever, reduced feed intake, weight loss, and death in fattening pigs. The NADC30-like PRRSV and PCV2d are the main circulating virus strains found in China. This study determines the impact of NADC30-like PRRSV and PCV2d mono-infection and coinfection on the immune system, organ pathology, and viral shedding in five-week-old post-weaned pigs. Pigs were randomly divided into six groups: PBS, PRRSV, PCV2, PRRSV-PCV2 coinfection (co), and PRRSV-PCV2 or PCV2-PRRSV sequential infections. Fever, dyspnea, decreased feed intake, weight loss, and pig deaths occurred in groups infected with PRRSV, Co-PRRSV-PCV2, and PRRSV-PCV2. The viral load was higher in Co-PRRSV-PCV2, PRRSV-PCV2, and PCV2-PRRSV than those mono-infected with PRRSV or PCV2. Additionally, cytokines (IFN-γ, TNF-α, IL-4, and IL-10) produced by pigs under Co-PRRSV-PCV2 and PRRSV-PCV2 groups were more intense than the other groups. Necropsy findings showed hemorrhage, emphysema, and pulmonary adhesions in the lungs of pigs infected with PRRSV. Smaller alveoli and widened lung interstitium were found in the Co-PRRSV-PCV2 and PRRSV-PCV2 groups. In conclusion, PRRSV and PCV2 coinfection and sequential infection significantly increased viral pathogenicity and cytokine responses, resulting in severe clinical signs, lung pathology, and death.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/fisiologia , Circovirus/patogenicidade , Coinfecção/virologia , Síndrome Respiratória e Reprodutiva Suína/virologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/fisiologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/patogenicidade , Animais , China , Infecções por Circoviridae/genética , Infecções por Circoviridae/imunologia , Infecções por Circoviridae/virologia , Circovirus/genética , Coinfecção/genética , Coinfecção/imunologia , Coinfecção/mortalidade , Feminino , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-4/genética , Interleucina-4/imunologia , Pulmão/imunologia , Pulmão/virologia , Masculino , Síndrome Respiratória e Reprodutiva Suína/genética , Síndrome Respiratória e Reprodutiva Suína/imunologia , Síndrome Respiratória e Reprodutiva Suína/mortalidade , Vírus da Síndrome Respiratória e Reprodutiva Suína/genética , Suínos , VirulênciaRESUMO
Porcine circovirus type 2 (PCV2) plays a key role in PCV2-associated disease (PCVAD) etiology and has yielded significant losses in the pig husbandry in the last 20 years. However, the impact of two recently described species of porcine circoviruses, PCV3 and PCV4, on the pork industry remains unknown. The presence of PCV3 has been associated with several clinical presentations in pigs. Reproductive failure and multisystemic inflammation have been reported most consistently. The clinical symptoms, anatomopathological changes and interaction with other pathogens during PCV3 infection in pigs indicate that PCV3 might be pathogenic for these animals and can cause economic losses in the swine industry similar to PCV2, which makes PCV3 worth including in the differential list as a cause of clinical disorders in reproductive swine herds. Moreover, subsequent studies indicate interspecies transmission and worldwide spreading of PCV3. To date, research related to PCV3 and PCV4 vaccine design is at early stage, and numerous aspects regarding immune response and virus characteristics remain unknown.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/isolamento & purificação , Doenças dos Suínos/virologia , Animais , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/transmissão , Infecções por Circoviridae/virologia , Circovirus/genética , Circovirus/imunologia , Circovirus/patogenicidade , Evolução Molecular , Genótipo , Especificidade de Hospedeiro , Humanos , Suínos , Doenças dos Suínos/epidemiologia , Desenvolvimento de Vacinas , Vacinas Virais , Zoonoses ViraisRESUMO
The recently discovered porcine circovirus 3 (PCV3) belongs to the Circovirus genus of the Circoviridae family together with the other three PCVs, PCV1, PCV2, and PCV4. As reported, PCV3 can infect pig, wild boar, and several other intermediate hosts, resulting in single or multiple infections in the affected animal. The PCV3 infection can lead to respiratory diseases, digestive disorders, reproductive disorders, multisystemic inflammation, and immune responses. Up to now, PCV3 infection, as well as the disease caused by PCV3, has been reported in many swine farms worldwide with high positive rates, which indicates that the virus may be another important pathogen in the swine industry. Therefore, we reviewed the current progress on epidemiology and pathobiology of PCV3, which may provide the latest knowledge of the virus and PCV3-related diseases.
Assuntos
Infecções por Circoviridae/patologia , Infecções por Circoviridae/veterinária , Circovirus/patogenicidade , Doenças dos Suínos/patologia , Animais , Infecções por Circoviridae/transmissão , Circovirus/classificação , Filogenia , Suínos , Doenças dos Suínos/transmissão , Doenças dos Suínos/virologiaRESUMO
The nucleotide oligomerization domain (NOD)-like receptor 2 (NOD2) is an intracellular pattern recognition receptor that detects components of peptidoglycans from bacterial cell walls. NOD2 regulates bowel microorganisms, provides resistance against infections such as diarrhea, and reduces the risk of inflammatory bowel diseases in humans and mice. We previously demonstrated that a specific porcine NOD2 polymorphism (NOD2-2197A > C) augments the recognition of peptidoglycan components. In this study, the relationships between porcine NOD2-2197A/C genotypes affecting molecular functions and symptoms in a porcine circovirus 2b (PCV2b)-spreading Duroc pig population were investigated. The NOD2 allele (NOD2-2197A) with reduced recognition of the peptidoglycan components augmented the mortality of pigs at the growing stage in the PCV2b-spreading population. Comparison of NOD2 allele frequencies in the piglets before and after invasion of PCV2b indicated that the ratio of NOD2-2197A decreased in the population after the PCV2b epidemic. This data indicated that functional differences caused by NOD2-2197 polymorphisms have a marked impact on pig health and livestock productivity. We suggest that NOD2-2197CC is a PCV2 disease resistant polymorphism, which is useful for selective breeding by reducing mortality and increasing productivity.
Assuntos
Infecções por Circoviridae , Resistência à Doença/genética , Proteína Adaptadora de Sinalização NOD2/genética , Suínos/genética , Animais , Proteínas do Capsídeo/genética , Infecções por Circoviridae/genética , Infecções por Circoviridae/mortalidade , Infecções por Circoviridae/patologia , Infecções por Circoviridae/transmissão , Circovirus/genética , Circovirus/imunologia , Circovirus/patogenicidade , Feminino , Predisposição Genética para Doença , Genótipo , Interações Hospedeiro-Patógeno/genética , Masculino , Filogenia , Polimorfismo de Nucleotídeo Único , Suínos/virologia , Doenças dos Suínos/genética , Doenças dos Suínos/mortalidade , Doenças dos Suínos/patologia , Doenças dos Suínos/transmissãoRESUMO
The objective of this study was to determine the pathogenicity of porcine circovirus type 2d (PCV2d) in pigs inoculated intranasally with PCV2d alone, PCV2d in combination with Mycoplasma hyopneumoniae or PCV2d in combination with porcine reproductive and respiratory syndrome virus (PRRSV). Pigs infected with PCV2d alone were asymptomatic. All pigs inoculated with either M. hyopneumoniae and PCV2d or with PCV2d and PRRSV developed porcine circovirus-associated disease (PCVAD), as characterized by a sudden onset of clinical signs and disseminated granulomatous inflammation. Inflammation was mainly present in lymph nodes and spleen, and occasionally in liver and kidney. Pigs in both of these dually infected groups also had significantly higher (P <0.05) microscopic lymphoid lesion scores and a significantly higher (P <0.05) number of PCV2-positive cells in lymph node tissue than did pigs inoculated with PCV2d alone. The M. hyopneumoniae and PRRSV combination potentiated the PCV2d load in the blood. Co-infection with PRRSV and PCV2d resulted in a significantly higher blood load of PCV2d compared with the M. hyopneumoniae and PCV2d combination. Successful reproduction of PCVAD in pigs appears to require PCV2d with at least one additional infectious agent, such as M. hyopneumoniae or PRRSV, for the full manifestation of disease.
Assuntos
Infecções por Circoviridae , Pneumonia Suína Micoplasmática , Síndrome Respiratória e Reprodutiva Suína , Doenças dos Suínos , Animais , Infecções por Circoviridae/veterinária , Circovirus/patogenicidade , Coinfecção/veterinária , Mycoplasma hyopneumoniae/patogenicidade , Vírus da Síndrome Respiratória e Reprodutiva Suína/patogenicidade , Suínos , VirulênciaRESUMO
Polarization of macrophages to different functional states is important for mounting responses against pathogen infections. Macrophages are the major target cells of porcine circovirus type 2 (PCV2), which is the primary causative agent of porcine circovirus-associated disease (PCVAD) leading to immense economic losses in the global swine industry. Clinically, PCV2 is often found to increase risk of other pathogenic infections yet the underlying mechanisms remain to be elusive. Here we found that PCV2 infection skewed macrophages toward a M1 status through reprogramming expression of a subset of M1-associated genes and M2-associated genes. Mechanistically, induction of M1-associated genes by PCV2 infection is dependent on activation of nuclear factor kappa B (NF-κB) and c-jun N-terminal kinase (JNK) signaling pathways whereas suppression of M2-associated genes by PCV2 is via inhibiting expression of jumonji domain containing-3 (JMJD3), a histone 3 Lys27 (H3K27) demethylase that regulates M2 activation of macrophages. Finally, we identified that PCV2 capsid protein (Cap) directly inhibits JMJD3 transcription to restrain expression of interferon regulatory factor (IRF4) that controls M2 macrophage polarization. Consequently, sustained infection of PCV2 facilitates bacterial infection in vitro. In summary, these findings showed that PCV2 infection functionally modulated M1 macrophage polarization via targeting canonical signals and epigenetic histone modification, which contributes to bacterial coinfection and virial pathogenesis.
Assuntos
Infecções por Actinobacillus/microbiologia , Actinobacillus pleuropneumoniae/patogenicidade , Infecções por Circoviridae/virologia , Circovirus/patogenicidade , Coinfecção , Macrófagos/microbiologia , Macrófagos/virologia , Infecções por Salmonella/microbiologia , Salmonella typhimurium/patogenicidade , Infecções por Actinobacillus/imunologia , Infecções por Actinobacillus/metabolismo , Actinobacillus pleuropneumoniae/imunologia , Animais , Células Cultivadas , Montagem e Desmontagem da Cromatina , Infecções por Circoviridae/imunologia , Circovirus/imunologia , Modelos Animais de Doenças , Epigênese Genética , Interações Hospedeiro-Patógeno , Fatores Reguladores de Interferon/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , NF-kappa B/metabolismo , Fenótipo , Infecções por Salmonella/imunologia , Infecções por Salmonella/metabolismo , Salmonella typhimurium/imunologia , Transdução de SinaisRESUMO
The clinical outcome of porcine circovirus 3 (PCV3) infection is still controversial. Herein, a novel PCV3 isolate (PCV3-China/DB-1/2017) with the molecular characterization of 24A and 27K in the Cap protein was used to inoculate three-week-old cesarean-derived, colostrum-deprived piglets. The nine PCV3 DB-1 inoculated piglets exhibited no obvious clinical symptoms or macroscopic lesions. PCV3 displayed a broad histotropism, including the heart, liver, spleen, lung, kidney, brain, lymph nodes, and tonsil, and the lungs and lymph nodes contained a higher quantity of viral genomes compared to that of the other organs. From 7 days after PCV3 DB-1 inoculation, the piglets showed obvious IgG antibody responses against PCV3 rCap-VLPs. The cumulative results demonstrated that PCV3 trend to low pathogenicity.
Assuntos
Infecções por Circoviridae/veterinária , Infecções por Circoviridae/virologia , Circovirus/patogenicidade , Doenças dos Suínos/virologia , Animais , Anticorpos Antivirais/metabolismo , Infecções Assintomáticas , Biomarcadores/metabolismo , China , Infecções por Circoviridae/imunologia , Infecções por Circoviridae/patologia , Circovirus/genética , Circovirus/imunologia , Circovirus/isolamento & purificação , Genoma Viral , Distribuição Aleatória , Sus scrofa , Suínos , Doenças dos Suínos/imunologia , Doenças dos Suínos/patologia , Carga Viral , Proteínas Virais/genética , Proteínas Virais/imunologiaRESUMO
In this study, we developed a real-time quantitative polymerase chain reaction (qPCR) assay based on a dual-labeled hydrolysis probe to simultaneously detect both duck circovirus (DuCV) 1 and DuCV-2. The reproducibility, sensitivity and specificity of the primer set and probe were evaluated using other duck pathogens. The detection limit was 20 copies per µL. The intra-assay coefficients of variation (CVs) were ≤ 0.73% and the inter-assay CVs were ≤ 1.89%. No cross-reaction occurred with other duck pathogens. In addition, the qPCR assay was successfully applied to the simultaneous detection of DuCV-1 and DuCV-2 in clinical field samples. Therefore, this assay will be useful for laboratory diagnosis and epidemiological field studies of DuCV.
Assuntos
Infecções por Circoviridae/diagnóstico , Circovirus/isolamento & purificação , Reação em Cadeia da Polimerase , Doenças das Aves Domésticas/diagnóstico , Animais , Infecções por Circoviridae/genética , Infecções por Circoviridae/virologia , Circovirus/genética , Circovirus/patogenicidade , DNA Viral/genética , Genótipo , Hidrólise , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/virologia , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Porcine circovirus 3 (PCV3) is a novel circovirus detected in pigs suffering from porcine dermatitis and nephropathy syndrome (PDNS), reproductive failure, and multisystemic infection. In this study, we identified PCV3 infection in aborted fetuses and reported the full-length genome sequence of a PCV3 strain identified from southern Vietnam. The complete genome of this PCV3 strain is 2000 nucleotides in length. We found that it shares 98.5-99.25% sequence identity with other reference sequences and that it clusters with the PCV3b subtype. Several specific mutated sites were found to be unique to this Vietnamese PCV3b strain, including I14M in the Rep protein and K139R, I150F, and P169T in the Cap protein. The sequence data that have been made publically available as part of this study will help investigators to better understand the molecular characteristics, genetic diversity, and evolutionary history of PCV3. Careful and in-depth investigations into the epidemiology, pathogenicity, and the evolution of this novel virus is a matter of urgent economic and agricultural interest in Vietnam.
Assuntos
Circovirus/genética , Genoma Viral/genética , Síndrome Definhante Multissistêmico de Suínos Desmamados/genética , Sequenciamento Completo do Genoma , Animais , Circovirus/patogenicidade , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Suínos/virologia , VietnãRESUMO
Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are two of the most significant pathogens affecting swine. Co-infections are common and result in respiratory disease and reduced weight gain in growing pigs. Although PRRS modified live virus (MLV) vaccines are widely used to decrease PRRS-associated losses, they are generally considered inadequate for disease control. The gut microbiome provides an alternative strategy to enhance vaccine efficacy and improve PRRS control. The objective of this study was to identify gut microbiome characteristics associated with improved outcome in pigs immunized with a PRRS MLV and co-challenged with PRRSV and PCV2b. Twenty-eight days after vaccination and prior to co-challenge, fecal samples were collected from an experimental population of 50 nursery pigs. At 42 days post-challenge, 20 pigs were retrospectively identified as having high or low growth outcomes during the post-challenge period. Gut microbiomes of the two outcome groups were compared using the Lawrence Livermore Microbial Detection Array (LLMDA) and 16S rDNA sequencing. High growth outcomes were associated with several gut microbiome characteristics, such as increased bacterial diversity, increased Bacteroides pectinophilus, decreased Mycoplasmataceae species diversity, higher Firmicutes:Bacteroidetes ratios, increased relative abundance of the phylum Spirochaetes, reduced relative abundance of the family Lachnospiraceae, and increased Lachnospiraceae species C6A11 and P6B14. Overall, this study identifies gut microbiomes associated with improved outcomes in PRRS vaccinated pigs following a polymicrobial respiratory challenge and provides evidence towards the gut microbiome playing a role in PRRS vaccine efficacy.
Assuntos
Circovirus/imunologia , Coinfecção/veterinária , Microbioma Gastrointestinal , Síndrome Respiratória e Reprodutiva Suína/prevenção & controle , Vírus da Síndrome Respiratória e Reprodutiva Suína/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/sangue , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Infecções por Circoviridae/virologia , Circovirus/patogenicidade , Coinfecção/virologia , Síndrome Respiratória e Reprodutiva Suína/imunologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/patogenicidade , Suínos , Doenças dos Suínos/prevenção & controle , Doenças dos Suínos/virologia , Vacinação , Potência de Vacina , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia , Vacinas Virais/administração & dosagemRESUMO
A total of 289 cloacal swabs from pigeons from 29 different breeders in Germany were collected. In addition, samples from pigeons exhibited at shows were collected. The detailed health status of the pigeon flocks was recorded. Samples were analysed for the presence of the recently discovered pigeon rotavirus and pigeon circovirus. Pigeon rotavirus was found in 10.3% and pigeon circoviruses was found in 65.5% of sampled pigeon lofts. The study revealed a strong relationship between the attendance of shows and the occurrence of different clinical signs. The higher prevalence of pigeon rotavirus in exhibited animals indicates that exhibitions are a risk factor for the transmission of this pathogen.
Assuntos
Doenças das Aves/virologia , Columbidae/virologia , Infecções por Rotavirus/virologia , Animais , Infecções por Circoviridae/virologia , Circovirus/patogenicidade , Alemanha , Prevalência , Fatores de Risco , Rotavirus/patogenicidadeRESUMO
Porcine circovirus type 4 (PCV4), a novel circovirus, was identified in pigs with serious symptoms, including porcine dermatitis and nephropathy syndrome (PDNS)-like signs, in China in 2019. This study investigated the prevalence and genome diversity of PCV4 in pigs from Guangxi Province, China, between 2015 and 2019. Thirteen of 257 (5.1%) samples were positive for PCV4, 9 of these (69.2%) PCV4-positive samples were coinfected with PCV2 or PCV3, and one PCV4-positive sample was coinfected with both PCV2 and PCV3. Three complete PCV4 genomes shared 36.9-73.8% nucleotide similarity with other representative circovirus genomes. Phylogenetic analysis indicated that PCV4 was most closely related to bat-associated circovirus and mink circovirus. In summary, this is the first epidemiological investigation and evolutionary analysis of PCV4 in Guangxi Province, China, and the results provide insight into the molecular epidemiology of PCV4.
Assuntos
Infecções por Circoviridae/genética , Circovirus/genética , Filogenia , Doenças dos Suínos/genética , Animais , Proteínas do Capsídeo/genética , China/epidemiologia , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/patologia , Infecções por Circoviridae/veterinária , Circovirus/patogenicidade , Genoma Viral/genética , Humanos , Suínos/genética , Suínos/virologia , Doenças dos Suínos/epidemiologia , Proteínas Virais/genéticaRESUMO
Recently, a novel PCV species (PCV3) has been detected in cases associated with sow mortality, lesions consistent with porcine dermatitis and nephropathy syndrome, reproductive failure and multisystemic inflammation. The pathogenesis and clinical significance of PCV3 is still unclear. In this study, we investigated the immunopathogenesis of PCV3 in CD/CD pigs. Four treatment groups, PCV3 (n=6), PCV3-KLH (n=6), control (n=3) and control-KLH (n=3), were included with PCV3-positive tissue homogenate (gc=3.38×1012 ml-1 and gc=1.04×1011 ml-1), confirmed by quantitative PCR (qPCR) and next-generation sequencing. Clinical signs, viremia, viral shedding, systemic cytokines, humoral (IgG) and T-cellular response were evaluated for 42 days. At necropsy, tissues were collected for histological evaluation and PCV3 detection by qPCR and in situ hybridization. No significant clinical signs were observed through the study. Viremia was detected in both PCV3-inoculated groups from 3 days post-inoculation (p.i.) until the end of the study. Nasal shedding was detected from 3 to 28 days p.i. and faecal shedding was transient. PCV3 induced an early (7 days p.i.) and sustained (42 days p.i.) IgG response. No significant T-cell response was observed. Histological evaluation demonstrated lesions consistent with multisystemic inflammation and perivasculitis. All tissues evaluated were positive by qPCR and virus replication was confirmed by positive in situ hybridization. This study demonstrated the potential role of PCV3 in subclinical infection, producing a mild, multisystemic inflammatory response, prolonged viremia detectable for 42 days p.i., presence of IgG humoral response and viral shedding in nasal secretions. More research is required to understand and elucidate potential co-factors necessary in the manifestation and severity of clinical disease.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/patogenicidade , Doenças dos Suínos/imunologia , Doenças dos Suínos/patologia , Animais , Anticorpos Antivirais/sangue , Infecções por Circoviridae/imunologia , Infecções por Circoviridae/patologia , Infecções por Circoviridae/virologia , Circovirus/fisiologia , Imunoglobulina G/sangue , Inflamação , Nariz/virologia , Suínos , Doenças dos Suínos/virologia , Viremia/veterinária , Viremia/virologia , Replicação Viral , Eliminação de Partículas ViraisRESUMO
Viral pathogens are being increasingly described in association with mass morbidity and mortality events in reptiles. However, our knowledge of reptile viruses remains limited. Herein, we describe the meta-transcriptomic investigation of a mass morbidity and mortality event in a colony of central bearded dragons (Pogona vitticeps) in 2014. Severe, extensive proliferation of the respiratory epithelium was consistently found in affected dragons. Similar proliferative lung lesions were identified in bearded dragons from the same colony in 2020 in association with increased intermittent mortality. Total RNA sequencing identified two divergent DNA viruses: a reptile-infecting circovirus, denoted bearded dragon circovirus (BDCV), and the first exogeneous reptilian chaphamaparvovirus-bearded dragon chaphamaparvovirus (BDchPV). Phylogenetic analysis revealed that BDCV was most closely related to bat-associated circoviruses, exhibiting 70% amino acid sequence identity in the Replicase (Rep) protein. In contrast, in the nonstructural (NS) protein, the newly discovered BDchPV showed approximately 31%-35% identity to parvoviruses obtained from tilapia fish and crocodiles in China. Subsequent specific PCR assays revealed BDCV and BDchPV in both diseased and apparently normal captive reptiles, although only BDCV was found in those animals with proliferative pulmonary lesions and respiratory disease. This study expands our understanding of viral diversity in captive reptiles.
Assuntos
Circovirus/isolamento & purificação , Parvoviridae/isolamento & purificação , Répteis/virologia , Infecções Respiratórias/veterinária , Animais , China/epidemiologia , Circovirus/classificação , Circovirus/genética , Circovirus/patogenicidade , Genoma Viral/genética , Lagartos/virologia , Pulmão/patologia , Parvoviridae/classificação , Parvoviridae/genética , Parvoviridae/patogenicidade , Filogenia , Prevalência , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/patologia , Infecções Respiratórias/virologia , Proteínas Virais/genéticaRESUMO
Porcine circovirus type 3 (PCV3) infection causes substantial economic losses in pig populations since its discovery in 2016. However, PCV3 molecular epidemiology remains need further study. In order to assess the prevalence of PCV3 infection in China, 4094 clinical samples from 271 pig farms in 10 provinces of China were evaluated by PCR. It was shown that the overall prevalence of PCV3 infection was 29.3 % (1200/4094) and 74.2 % (201/271) at sample and farm levels respectively, suggesting that PCV3 infection is prevalent in China. Furthermore, a statistical analysis showed PCV3 might exacerbate PCV2 and PRRSV infection rate and have a potential association with pig clinical disease. In addition, we sequenced the entire genome of 57 PCV3 strains; homology analysis showed that PCV3 strains have more than 96 % similarities at the nucleotide level, and PCV3 shares less than 60 % similarities with other circoviruses. By comparing the total 673 PCV3 strains from the NCBI GenBank, we found the major of amino acid mutations are located in predicted epitope regions and the mutations ratio changed during PCV3 evolution. Phylogenetic analysis revealed that all isolates belonged to PCV3a and PCV3b, and increasing PCV3a and decreasing PCV3b trends were observed during PCV3 evolution. Overall, this study provides important insights for understanding PCV3 prevalence, pathogenesis, and evolution and will guide future efforts to develop effective preventive and control measures.
Assuntos
Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/veterinária , Circovirus/genética , Circovirus/patogenicidade , Evolução Molecular , Doenças dos Suínos/epidemiologia , Animais , China/epidemiologia , Circovirus/classificação , Fazendas , Genoma Viral , Gado/virologia , Mutação , Filogenia , Prevalência , Suínos , Doenças dos Suínos/virologia , Proteínas Virais/genética , Sequenciamento Completo do GenomaRESUMO
Porcine circovirus type 2 (PCV2) is an important pathogen of the current pig industry. The Wnt signalling pathway plays an important role in the growth of young animals. In this study, we mainly elucidated the relationship between PCV2 and the Wnt signalling pathway. In an in vivo experiment in mice, we demonstrated the downregulatory effects of PCV2 infection on expression levels of downstream components of the Wnt signalling pathway. Weight loss in mice was reversed by activating the Wnt signalling pathway, and the body weight was still significantly higher than that in mice infected with PCV2. We detected levels of growth hormone (GH) in the liver and sera, which showed that GH was also downregulated in mice challenged with PCV2. Lithium chloride, the activator of Wnt signalling, upregulated GH, albeit to a significantly lesser degree than that in corresponding non-stimulated mock mice. In vitro studies showed that PCV2 infection downregulated protein expression of ß-catenin and mRNA expression of matrix metallopeptidase-2 (Mmp2), downregulated protein expression of ß-catenin in the cytoplasm and nucleus, and reduced the activity of the TCF/LEF promoter, demonstrating that PCV2 inhibited activation of the Wnt signalling pathway in vitro. Finally, we found that Rep protein of PCV2 might be responsible for the inhibitory effect.
Assuntos
Circovirus/patogenicidade , Via de Sinalização Wnt , Animais , Linhagem Celular , Núcleo Celular/metabolismo , Núcleo Celular/virologia , Circovirus/classificação , Citoplasma/metabolismo , Citoplasma/virologia , Feminino , Hormônio do Crescimento/antagonistas & inibidores , Hormônio do Crescimento/genética , Metaloproteinase 2 da Matriz/genética , Camundongos , Camundongos Endogâmicos ICR , Suínos , Ativação Transcricional , Redução de Peso , beta Catenina/genéticaRESUMO
BACKGROUND: Dysfunction of endothelial cells and vascular system is one of the most important pathological changes of porcine circovirus disease (PCVD) caused by porcine circovirus type 2 (PCV2). PCV2-infected endothelial cells can upregulate the production of endothelial-derived IL-8, which can inhibit the maturation of dendritic cells. Endothelial-derived IL-8 has different structural and biological characteristics compared with monocyte-derived IL-8. However, the mechanism of endothelial-derived IL-8 production is still unclear. RESULTS: Key molecules of RIG-I-like signaling pathway RIG-I, MDA-5, MAVS and a key molecule of JNK signaling pathway c-Jun in PCV2-infected porcine iliac artery endothelial cells (PIECs) were upregulated significantly detected with quantitative PCR, Western blot and fluorescence confocal microscopy, while no significant changes were found in NF-κB signaling pathway. Meanwhile, the expression of endothelial-derived IL-8 was downregulated after RIG-I, MDA-5, or MAVS genes in PIECs were knocked down and PIECs were treated by JNK inhibitor. CONCLUSIONS: PCV2 can activate RIG-I/MDA-5/MAVS/JNK signaling pathway to induce the production of endothelial-derived IL-8 in PIECs, which provides an insight into the further study of endothelial dysfunction and vascular system disorder caused by PCV2.
Assuntos
Infecções por Circoviridae/veterinária , Células Endoteliais/virologia , Interleucina-8/metabolismo , Transdução de Sinais , Animais , Células Cultivadas , Infecções por Circoviridae/metabolismo , Circovirus/patogenicidade , Células Endoteliais/metabolismo , Técnicas de Silenciamento de Genes/métodos , Técnicas de Silenciamento de Genes/veterinária , Artéria Ilíaca/metabolismo , Artéria Ilíaca/virologia , Interleucina-8/genética , Suínos , Doenças dos Suínos/metabolismo , Doenças dos Suínos/virologiaRESUMO
Porcine circovirus 3 (PCV3) has been detected in major pig-producing countries around the world since its first report in the US in 2016. Most current studies have focused on epidemiological investigations and detection methods of PCV3 because of lack of live virus strains for research on its pathogenesis in porcine cells or even in pigs. We constructed a recombinant plasmid pCMV-Cap carrying the PCV3 orf2 gene to investigate the effects of capsid (Cap) protein expression on autophagic response in human embryonic kidney cell line 293T (HEK293T). We demonstrate that PCV3 Cap protein induced complete autophagy shown as formation of autophagosomes and autophagosome-like vesicles as well as LC3-II conversion from LC3-I via inhibiting phosphorylation of the mammalian target of rapamycin (mTOR) in HEK293T cells. The ubiquitin-proteasome pathway is also involved in the autophagy process. These findings provide insight for further exploration of PCV3 pathogenetic mechanisms in porcine cells.